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New structural units in molybdenum oxyfluoride chemistry

2013-06-18T09:01:02Z

Abstract: The solvothermal syntheses and crystal structures of five new molybdenum oxyfluorides are presented. These exhibit three novel structural units, each containing Mo in a reduced oxidation state: a dimeric [MO2O4F2(C2H8N2)(2)] unit (Mo4+), a tetrameric [Mo4O8F10](6-) unit (Mo5+) and an infinite chain [MoOF3](-) unit (Mo4+). Mo-Mo bonding is observed in each of the new building units. Description: This article was supported with EPSRC funding.

An ionothermally prepared S=1/2 vanadium oxyfluoride kagome lattice

2013-06-16T04:31:22Z

Abstract: Frustrated magnetic lattices offer the possibility of many exotic ground states that are of great fundamental importance. Of particular significance is the hunt for frustrated spin-1/2 networks as candidates for quantum spin liquids, which would have exciting and unusual magnetic properties at low temperatures. The few reported candidate materials have all been based on d9 ions. Here, we report the ionothermal synthesis of [NH4]2[C7H14N][V7O6F18], an inorganic-organic hybrid solid that contains a S = 1/2 kagome network of d1 V4+ ions. The compound exhibits a high degree of magnetic frustration, with significant antiferromagnetic interactions but no long-range magnetic order or spin-freezing above 2 K, and appears to be an excellent candidate for realizing a quantum spin liquid ground state in a spin-1/2 kagome network.

Two-dimensional magnetohydrodynamic turbulence in the small Prandtl number limit

2013-06-16T00:34:44Z

Abstract: In this paper we introduce a new method for computations of two-dimensional magnetohydrodynamic (MHD) turbulence at low magnetic Prandtl number $\Pra=\nu/\eta$. When $\Pra \ll 1$, the magnetic field dissipates at a scale much larger than the velocity field. The method we utilise is a novel hybrid contour--spectral method, the ``Combined Lagrangian Advection Method'', formally to integrate the equations with zero viscous dissipation. The method is compared with a standard pseudo-spectral method for decreasing $\Pra$ for the problem of decaying two-dimensional MHD turbulence. The method is shown to agree well for a wide range of imposed magnetic field strengths. Examples of problems for which such a method may prove invaluable are also given.

Root traits for infertile soils

2013-06-13T14:31:00Z

Abstract: Crop production is often restricted by the availability of essential mineral elements. For example, the availability of N, P, K, and S limits low-input agriculture, the phytoavailability of Fe, Zn, and Cu limits crop production on alkaline and calcareous soils, and P, Mo, Mg, Ca,and K deficiencies, together with proton, Al and Mn toxicities, limit crop production on acid soils. Since essential mineral elements are acquired by the root system, the development of crop genotypes with root traits increasing their acquisition should increase yields on infertile soils. This paper examines root traits likely to improve the acquisition of these elements and observes that, although the efficient acquisition of a particular element requires a specific set of root traits, suites of traits can be identified that benefit the acquisition of a group of mineral elements. Elements can be divided into three Groups based on common trait requirements. Group 1 comprises N, S, K, B, and P. Group 2 comprises Fe, Zn, Cu, Mn, and Ni. Group 3 contains mineral elements that rarely affect crop production. It is argued that breeding for a limited number of distinct root ideotypes,addressing particular combinations of mineral imbalances, should be pursued.

'Verde di migrazione' : L'estetica perturbante dell'enstrangement ne La mano che non mordi di Ornela Vorpsi

2013-06-13T10:01:01Z

Abstract: Questo articolo analizza la rappresentazione degli effetti dell’alienazione provocati dalla migrazione ne La mano che non mordi di Ornela Vorpsi tramite il legame che essa crea tra frammentazione dell’io e l’incontro con l’estetica. L’arte, nella stessa maniera della soggettività dissociata dalla migrazione, crea un mondo fittizio, e promuove la rimozione della realtà personale – qualcosa che puo’ rivelarsi distruttivo della stabilità psicologica dell’individuo. Nella presente novella, un tale incontro con un’estetica perturbante (eco dell’episodio parallelo nel Ritratto di Dorian Gray di Oscar Wilde) si allinea con l’esperienza del ritorno dei migranti al loro paese d’origine, e crea una schiera di personaggi segnati persino fisicamente dalla perdita della stabilità precedente della loro identità. Description: Special issue: Les mouvements migratoires entre réalité et représentation

Female putty-nosed monkeys use experimentally altered contextual information to disambiguate the cause of male alarm calls

2013-06-12T15:01:01Z

Abstract: Many animal vocal signals are given in a wide range of contexts which can sometimes have little in common. Yet, to respond adaptively, listeners must find ways to identify the cause of a signal, or at least rule out alternatives. Here, we investigate the nature of this process in putty-nosed monkeys, a forest primate. In this species, adult males have a very restricted repertoire of vocalizations which are given in response to a wide variety of events occurring under conditions of limited visibility. We carried out a series of field playback experiments on females (N = 6) in a habituated group in Gashaka Gumti National Park, Nigeria, in which male alarm/loud calls were presented either alone, or following acoustic information that simulated the occurrence of natural disturbances. We demonstrate that listeners appear to integrate contextual information in order to distinguish among possible causes of calls. We conclude that, in many cases, pragmatic aspects of communication play a crucial role in call interpretation and place a premium on listeners' abilities to integrate information from different sources.

On energetics and inertial range scaling laws of two-dimensional magnetohydrodynamic turbulence

2013-06-11T23:31:04Z

Abstract: We study two-dimensional magnetohydrodynamic turbulence, with an emphasis on its energetics and inertial range scaling laws. A detailed spectral analysis shows that dynamo triads (those converting kinetic into magnetic energy) are associated with a direct magnetic energy flux while anti-dynamo triads (those converting magnetic into kinetic energy) are associated with an inverse magnetic energy flux. As both dynamo and anti-dynamo interacting triads are integral parts of the direct energy transfer, the anti-dynamo inverse flux partially neutralizes the dynamo direct flux, arguably resulting in relatively weak direct energy transfer and giving rise to dynamo saturation. This result is consistent with a qualitative prediction of energy transfer reduction owing to Alfv\'en wave effects by the Iroshnikov--Kraichnan theory (which was originally formulated for magnetohydrodynamic turbulence in three dimensions). We numerically confirm the correlation between dynamo action and direct magnetic energy flux and investigate the applicability of quantitative aspects of the Iroshnikov--Kraichnan theory to the present case, particularly its predictions of energy equipartition and $k^{-3/2}$ spectra in the energy inertial range. It is found that for turbulence satisfying the Kraichnan condition of magnetic energy at large scales exceeding total energy in the inertial range, the kinetic energy spectrum, which is significantly shallower than $k^{-3/2}$, is shallower than its magnetic counterpart. This result suggests no energy equipartition. The total energy spectrum appears to depend on the energy composition of the turbulence but is clearly shallower than $k^{-3/2}$ for $r\approx2$, even at moderate resolutions. Here $r\approx2$ is the magnetic-to-kinetic energy ratio during the stage when the turbulence can be considered fully developed. The implication of the present findings is discussed in conjunction with further numerical results on the dependence of the energy dissipation rate on resolution. Description: L. Blackbourn was supported by an EPSRC post-graduate studentship.

Locating South China in Rodinia and Gondwana : A fragment of greater India lithosphere?

2013-06-10T16:01:02Z

Abstract: From the formation of Rodinia at the end of the Mesoproterozoic to the commencement of Pangea breakup at the end of the Paleozoic, the South China craton first formed and then occupied a position adjacent to Western Australia and northern India. Early Neoproterozoic suprasubduction zone magmatic arc-backarc assemblages in the craton range in age from ca. 1000 Ma to 820 Ma and display a sequential northwest decrease in age. These relations suggest formation and closure of arc systems through southeast-directed subduction, resulting in progressive northwestward accretion onto the periphery of an already assembled Rodinia. Siliciclastic units within an early Paleozoic succession that transgresses across the craton were derived from the southeast and include detritus from beyond the current limits of the craton. Detrital zircon age spectra require an East Gondwana source and are very similar to the Tethyan Himalaya and younger Paleozoic successions from Western Australia, suggesting derivation from a common source and by inference accumulation in linked basins along the northern margin of Gondwana, a situation that continued until rifting and breakup of the craton in the late Paleozoic. Description: This work was supported by NERC [Grant ID NE/J021822/1]

‘“Hier ist die Grenze […] Wollen wir darüber hinaus?” : Borders and Ambiguity in Fontane’s "Unwiederbringlich"

2013-05-31T12:31:01Z

Abstract: Theodor Fontane’s „Unwiederbringlich“ may be productively read as an exploration of boundaries. The historical context creates a distinction between bordered and unbordered spaces, between crossing thresholds and staying within limits. This double focus mirrors the text’s thematics, in which clear thresholds in morality and time are balanced against exhortations to relativism. The represented landscape reproduces this antithesis and functions as a symbolic map against which Holk’s and Christine’s actions and feelings may be read, charting trespass and ironic misunderstanding. A study of boundaries in the text reveals a complex and multifaceted spatial symbol appropriate to a literary exploration of thresholds in human life. Description: Sonderheft "Grenzen im Raum, Grenzen in der Literatur"

Bread and Cinema : Baghdad in al-Nakhla wa-'l-jiran by Gha'ib Tu'ma Farman

2013-05-31T11:31:03Z

Abstract: Al-Nakhla wa-'l-jīrān (‘The Palm Tree and the Neighbours', 1966) has been largely neglected outside the Arab world, despite being hailed as ‘the true beginning’ of the Iraqi novel. After an introduction to Farmān and the intellectual climate in which he started writing, the article goes on to discuss: the sophisticated realism of the novel, by contrasting it to that of its alleged sources, including Naguib Mahfouz's Zuqāq al-midaqq; and the depiction of Baghdad through a detailed analysis of how space is evoked in the text (with reference to the readings of the novel by Arab critics and also to the writings of Auerbach and Bachelard). The representations of Baghdad range from lyrical evocations to humorous and poignant dramatisations of the city during the British occupation in World War II. Space is seen lived, imagined and reinvented by its inhabitants through traditional storytelling and the world of cinema in a way that gives life and meaning to the much abused literary term of realism.

From subduction to collision in the northern Tibetan plateau : evidence from the early Silurian clastic rocks, northwestern China

2013-05-31T09:31:02Z

Abstract: The Qilian Orogen records early Paleozoic collisional suturing of the Qaidam Block and the Central Qilian Block to the North China Craton. The composition and U-Pb age of detrital zircons and the composition of Cr-spinels from the Early Silurian Lujiaogou and Angzanggou formations in the northern part of orogen indicate derivation from evolving oceanic and continental source terranes. Heavy-mineral chemistry indicates the incorporation of suprasubduction zone-type ophiolitic detritus in addition to continent-derived material. Integrating these chemical and age data with regional data on the duration of subduction-related magmatic activity, syn- and postcollisional granitic rocks, and high-pressure metamorphic rocks constrains the transformation from oceanic subduction to continental collision to 450-440 Ma. The collision resulted in a flood of detritus into the northern part of the orogen from the Central Qilian Block, which masked input from the intervening magmatic arc, implying rapid exposure of the block.

khushub musannada (Q 63:4) and ESA m{s1,s3}nd.

2013-05-30T12:31:04Z

Abstract: This paper will enquire into the possibility of a relationship between musannadah in QurΜān 63. 4 and musnad (Epigraphic South Arabian (ESA) mчnd), which is used to denote Epigraphic Arabic scripts and inscriptions. The question to be dealt with here is whether and how different interpretations evolved. In addition, the paper considers whether musannadah can be interpreted in the light of Epigraphic South Arabian mчnd —and, subsequently, Arabic musnad denoting Ancient Arabian scripts —or, more specifically, the Ancient South Arabian monumental script. This would constitute a new interpretation and show the hypocrites to be corroded by fear like carved or rotten timbers; therefore lexicographical and exegetical as well as relevant secondary literature will be surveyed diachronically. The discussion will include proposed etymologies for the term musnad and its description in early Arabic sources such as Hamdānī’s Iklīl, the Gharīb literature, Дadīth collections, and historical works such as Jawād ΚAlī’s alMufa ΒΒal fītārīkh al-Κarab qabl al-islām.

The continental record and the generation of continental crust

2013-05-30T12:01:02Z

Abstract: Continental crust is the archive of Earth history. The spatial and temporal distribution of Earth's record of rock units and events is heterogeneous; for example, ages of igneous crystallization, metamorphism, continental margins, mineralization, and seawater and atmospheric proxies are distributed about a series of peaks and troughs. This distribution reflects the different preservation potential of rocks generated in different tectonic settings, rather than fundamental pulses of activity, and the peaks of ages are linked to the timing of supercontinent assembly. The physio-chemical resilience of zircons and their derivation largely from felsic igneous rocks means that they are important indicators of the crustal record. Furthermore, detrital zircons, which sample a range of source rocks, provide a more representative record than direct analysis of grains in igneous rocks. Analysis of detrital zircons suggests that at least ∼60%–70% of the present volume of the continental crust had been generated by 3 Ga. Such estimates seek to take account of the extent to which the old crustal material is underrepresented in the sedimentary record, and they imply that there were greater volumes of continental crust in the Archean than might be inferred from the compositions of detrital zircons and sediments. The growth of continental crust was a continuous rather than an episodic process, but there was a marked decrease in the rate of crustal growth at ca. 3 Ga, which may have been linked to the onset of significant crustal recycling, probably through subduction at convergent plate margins. The Hadean and Early Archean continental record is poorly preserved and characterized by a bimodal TTG (tonalites, trondhjemites, and granodiorites) and greenstone association that differs from the younger record that can be more directly related to a plate-tectonic regime. The paucity of this early record has led to competing and equivocal models invoking plate-tectonic– and mantle-plume–dominated processes. The 60%–70% of the present volume of the continental crust estimated to have been present at 3 Ga contrasts markedly with the <10% of crust of that age apparently still preserved and requires ongoing destruction (recycling) of crust and subcontinental mantle lithosphere back into the mantle through processes such as subduction and delamination.

Detrital zircon record and tectonic setting

2013-05-30T12:01:01Z

Abstract: Detrital zircon spectra reflect the tectonic setting of the basin in which they are deposited. Convergent plate margins are characterized by a large proportion of zircon ages close to the depositional age of the sediment, whereas sediments in collisional, extensional and intracratonic settings contain greater proportions with older ages that reflect the history of the underlying basement. These differences can be resolved by plotting the distribution of the difference between the measured crystallization ages (CA) of individual zircon grains present in the sediment and the depositional age (DA) of the sediment. Application of this approach to successions where the original nature of the basin and/or the link to source are no longer preserved constrains the tectonic setting in which the sediment was deposited.

Ecological causes of morphological evolution in the three-spined stickleback

2013-05-30T11:31:02Z

Abstract: The central assumption of evolutionary theory is that natural selection drives the adaptation of populations to local environmental conditions, resulting in the evolution of adaptive phenotypes. The three-spined stickleback (Gasterosteus aculeatus) displays remarkable phenotypic variation, offering an unusually tractable model for understanding the ecological mechanisms underpinning adaptive evolutionary change. Using populations on North Uist, Scotland we investigated the role of predation pressure and calcium limitation on the adaptive evolution of stickleback morphology and behavior. Dissolved calcium was a significant predictor of plate and spine morph, while predator abundance was not. Stickleback latency to emerge from a refuge varied with morph, with populations with highly reduced plates and spines and high predation risk less bold. Our findings support strong directional selection in three-spined stickleback evolution, driven by multiple selective agents.

Unravelling the structure of viral replication complexes at super-resolution

2013-05-30T11:31:01Z

Abstract: During infection, many RNA viruses produce characteristic inclusion bodies that contain both viral and host components. These structures were first described over a century ago and originally termed “X-bodies,” as their function was not immediately appreciated. Whilst some inclusion bodies may represent cytopathic by-products of viral protein over-accumulation, X-bodies have emerged as virus “factories,” quasi-organelles that coordinate diverse viral infection processes such as replication, protein expression, evasion of host defenses, virion assembly, and intercellular transport. Accordingly, they are now generally referred to as viral replication complexes (VRCs). We previously used confocal fluorescence microscopy to unravel the complex structure of X-bodies produced by Potato virus X (PVX). Here we used 3D-structured illumination (3D-SIM) super-resolution microscopy to map the PVX X-body at a finer scale. We identify a previously unrecognized membrane structure induced by the PVX “triple gene block” (TGB) proteins, providing new insights into the complex interplay between virus and host within the X-body.

Two-stage threshold representations

2013-06-04T08:31:01Z

Abstract: We study two-stage choice procedures in which the decision maker first preselects the alternatives whose values according to a criterion pass a menu-dependent threshold, and then maximizes a second criterion to narrow the selection further. This framework overlaps with several existing models that have various interpretations and impose various additional restrictions on behavior. We show that the general class of procedures is characterized by acyclicity of the revealed "first-stage separation relation."

Dissociation or cyclization : options for a triad of radicals released from oxime carbamates

2013-05-30T09:01:04Z

Abstract: A set of oxime carbamates, having N-alkyl- and N,N-dialkyl-substituents, was prepared via carbonyldiimidazole intermediates. It was shown by EPR spectroscopy that they underwent clean homolysis of their NO bonds on UV photolysis. During photolysis of acetophenone O-allylcarbamoyl oxime the corresponding oxazolidin-2-onylmethyl radical was detected by EPR spectroscopy, providing the first evidence that N-mono-substituted carbamoyloxyl radicals can hold their structural integrity. N,N-Di-substituted carbamoyloxyl radicals dissociated rapidly at the lowest accessible temperatures. Above room temperature both types of oxime carbamate acted as selective new precursors for aminyl and iminyl radicals. Rate parameters were measured for 5-exo-cyclization of N-benzyl-N-pent-4-enylaminyl radicals; the rate constant was smaller than for C-centered and O-centered analogs. Oxime carbamates derived from the volatile diethylamine afforded aryl-iminyl radicals that proved convenient for phenanthridine preparations.

Auditory same/different concept learning and generalization in black-capped chickadees (Poecile atricapillus)

2013-05-29T15:01:02Z

Abstract: Abstract concept learning was thought to be uniquely human, but has since been observed in many other species. Discriminating same from different is one abstract relation that has been studied frequently. In the current experiment, using operant conditioning, we tested whether black-capped chickadees (Poecile atricapillus) could discriminate sets of auditory stimuli based on whether all the sounds within a sequence were the same or different from one another. The chickadees were successful at solving this same/different relational task, and transferred their learning to same/different sequences involving novel combinations of training notes and novel notes within the range of pitches experienced during training. The chickadees showed limited transfer to pitches that was not used in training, suggesting that the processing of absolute pitch may constrain their relational performance. Our results indicate, for the first time, that black-capped chickadees readily form relational auditory same and different categories, adding to the list of perceptual, behavioural, and cognitive abilities that make this species an important comparative model for human language and cognition.

Emmanuel de Martonne et la naissance de la Grande Roumanie

2013-05-29T15:01:01Z

Abstract: The research of Emmanuel de Martonne (1873–1955) in the field of physical goegraphy, in its many forms, made him the leading geographer, not only in France, but on an international level. His immense body of work also covers human geography : La Valachie, a doctoral thesis published in 1902, remains a model of the Vidalian regional monograph. But it must be pointed out that de Martonne’s work is not limited to a strictly scientific and disinterested domain. By its very nature, his geographical work is bound up with history, and therefore political circumstances, something which is clearly displayed in his long and passionate relationship with Romania. It is before the Great War, on the frontier between Hungary and Romania, that Emmanuel de Martonne begins his work as a geographer. Enamoured of a landscape and a people, this eminent scholar will serve the cause of ‘Greater Romania’ : firstly as a supporter of Romanian intervention in the European conflict, then as a ‘drawer of frontiers’ at the Versailles Peace Conference. Here we see how geography can be used in political projects, rivalries over territories and debates on identity.

Associative learning in insects : evolutionary models, mushroom bodies, and a neuroscientific conundrum

2013-05-29T14:31:02Z

Abstract: Environmental predictability has for many years been posited to be a key variable in whether learning is expected to evolve in particular species, a claim revisited in two recent papers. However, amongst many researchers, especially neuroscientists, consensus is building for a very different view, namely that learning ability may be an emergent property of nervous systems and, thus, all animals with nervous systems should be able to learn. Here we explore these differing views, sample research on associative learning in insects, and review our own work demonstrating learning in larval antlions (Neuroptera: Myrmeleontidae), a highly unlikely insect candidate. We conclude by asserting that the capacity for associative learning is the default condition favored by neuroscientists: Whenever selection pressures favor evolution of nervous systems, the capacity for associative learning follows ipso facto. Nonetheless, to reconcile these disparate views, we suggest that (a) models for the evolution of learning may instead be models for conditions overriding behavioral plasticity; and, (b) costs of learning in insects may be, in fact, costs associated with more complex cognitive skills, skills that are just beginning to be discovered, rather than simple associative learning.

What hummingbirds can tell us about cognition in the wild.

2013-05-29T14:31:02Z

Abstract: Here we review around 20 years of experimental data that we have collected during tests of cognitive abilities of free-living, wild rufous hummingbirds Selasphorus rufus at their breeding grounds in southwestern Alberta. Because these birds are readily trained to feed from artificial flowers they have proved a useful system for testing cognitive abilities of an animal outside the box wherein animal cognitive abilities are so often tested in the laboratory. And, although these data all come from a single species in a single location, the long-term aim of this work is to make a contribution to our understanding of the evolution of cognitive abilities, by examining the relationship between the ecological demands these birds face and their cognitive abilities. Testing predictions based on our knowledge of their ecology we have found that, while these birds aggressively defend a territory and display to females during the time we train and test them, they can learn and remember the locations of rewarded flowers, what those flowers look like, and when they are likely to contain food. Small-brained though they may be, these 3g hummingbirds appear to have cognitive capabilities that are not only well matched to their ecological demands, they are in at least some instances better (more capacious) than those of animals tested in the laboratory.

Acoustic mechanisms of a species-based discrimination of the chick-a-dee call in sympatric black-capped (Poecile atricapillus) and mountain chickadees (P. gambeli)

2013-05-29T12:01:03Z

Abstract: Previous perceptual research with black-capped and mountain chickadees has demonstrated that these species treat each other’s namesake chick-a-dee calls as belonging to separate, open-ended categories. Further, the terminal dee portion of the call has been implicated as the most prominent species marker. However, statistical classification using acoustic summary features suggests that all note-types contained within the chick-a-dee call should be sufficient for species classification. The current study seeks to better understand the note-type based mechanisms underlying species-based classification of the chick-a-dee call by black-capped and mountain chickadees. In two, complementary, operant discrimination experiments, both species were trained to discriminate the species of the signaler using either entire chick-a-dee calls, or individual note-types from chick-a-dee calls. In agreement with previous perceptual work we find that the D note had significant stimulus control over species-based discrimination. However, in line with statistical classifications, we find that all note-types carry species information. We discuss reasons why the most easily discriminated note-types are likely candidates to carry species-based cues.

Specialized learning in antlions (Neuroptera: Myrmeleontidae), pit-digging predators, shortens vulnerable larval stage

2013-05-29T12:01:01Z

Abstract: Unique in the insect world for their extremely sedentary predatory behavior, pit-dwelling larval antlions dig pits, and then sit at the bottom and wait, sometimes for months, for prey to fall inside. This sedentary predation strategy, combined with their seemingly innate ability to detect approaching prey, make antlions unlikely candidates for learning. That is, although scientists have demonstrated that many species of insects possess the capacity to learn, each of these species, which together represent multiple families from every major insect order, utilizes this ability as a means of navigating the environment, using learned cues to guide an active search for food and hosts, or to avoid noxious events. Nonetheless, we demonstrate not only that sedentary antlions can learn, but also, more importantly, that learning provides an important fitness benefit, namely decreasing the time to pupate, a benefit not yet demonstrated in any other species. Compared to a control group in which an environmental cue was presented randomly vis-à-vis daily prey arrival, antlions given the opportunity to associate the cue with prey were able to make more efficient use of prey and pupate significantly sooner, thus shortening their long, highly vulnerable larval stage. Whereas ‘‘median survival time,’’ the point at which half of the animals in each group had pupated, was 46 days for antlions receiving the Learning treatment, that point never was reached in antlions receiving the Random treatment, even by the end of the experiment on Day 70. In addition, we demonstrate a novel manifestation of antlions’ learned response to cues predicting prey arrival, behavior that does not match the typical ‘‘learning curve’’ but which is well-adapted to their sedentary predation strategy. Finally, we suggest that what has long appeared to be instinctive predatory behavior is likely to be highly modified and shaped by learning. Description: Formal Correction: This article has been formally corrected to address the following errors. Figures 2 and 3 were switched in production. The image listed as Figure 3 is actually Figure 2, and the image listed as Figure 2 is actually Figure 3. The legends are correct.

Imprint of climate and climate change in alluvial riverbeds : Continental United States, 1950-2011

2013-05-29T08:31:04Z

Abstract: Alluvial riverbed elevation responds to the balance between sediment supply and transport capacity, which is largely dependent on climate and its translation into fluvial discharge. We examine these relations using U.S. Geological Survey streamflow and channel measurements in conjunction with basin characteristics for 915 reference ("least disturbed") measurement stations across the conterminous United States for the period A.D. 1950–2011. We find that (1) 68% of stations have bed elevation change (BEC) trends (p < 0.05) with median values of +0.5 cm/yr for aggradation and –0.6 cm/yr for degradation, with no obvious relation to drainage basin structure, physiography, or lithology; (2) BEC correlates with drainage basin area; (3) high-flow variability (Q90/Q50, where Q is discharge and 90 and 50 are annual flow percentiles) translates directly into the magnitude, though not the direction, of BEC, after accounting for the scale dependence; (4) Q90/Q50 declines systematically from dry to wet climates, producing disproportionately high rates of BEC in drier regions; and (5) marked increases in precipitation and streamflow occurred disproportionately at dry sites, while streamflow declined disproportionately at wet sites. Climatic shifts in streamflow have the potential to increase/decrease sediment flux and thus affect riverbed elevation by altering flood frequency. These unforeseen responses of bed elevation to climate and climate change have important implications for sediment budgets, longitudinal profiles, ecology, and river management. Description: This work was partially supported by a Natural Environment Research Council Ph.D. studentship to Slater.

From God's peace to the king's order : late medieval limitations on non-royal warfare

2013-05-29T08:31:02Z

Evidence of improving antiretroviral therapy treatment delays : an analysis of eight years of programmatic outcomes in Blantyre, Malawi

2013-05-28T15:31:01Z

Abstract: Abstract Background: Impressive achievements have been made towards achieving universal coverage of antiretroviral therapy (ART) in sub-Saharan Africa. However, the effects of rapid ART scale-up on delays between HIV diagnosis and treatment initiation have not been well described. Methods: A retrospective cohort study covering eight years of ART initiators (2004–2011) was conducted at Queen Elizabeth Central Hospital (QECH) in Blantyre, Malawi. The time between most recent positive HIV test and ART initiation was calculated and temporal trends in delay to initiation were described. Factors associated with time to initiation were investigated using multivariate regression analysis. Results: From 2004–2011, there were 15,949 ART initiations at QECH (56% female; 8% children [0–10 years] and 5% adolescents [10–20 years]). Male initiators were likely to have more advanced HIV infection at initiation than female initiators (70% vs. 64% in WHO stage 3 or 4). Over the eight years studied, there were declines in treatment delay, with 2011 having the shortest delay at 36.5 days. On multivariate analysis CD4 count <50 cells/μl (adjusted geometric mean ratio [aGMR]: aGMR: 0.53, bias-corrected accelerated [BCA] 95% CI: 0.42-0.68) was associated with shorter ART treatment delay. Women (aGMR: 1.12, BCA 95% CI: 1.03-1.22) and patients diagnosed with HIV at another facility outside QECH (aGMR: 1.61, BCA 95% CI: 1.47-1.77) had significantly longer treatment delay. Conclusions: Continued improvements in treatment delays provide evidence that universal access to ART can be achieved using the public health approach adopted by Malawi However, the longer delays for women and patients diagnosed at outlying sites emphasises the need for targeted interventions to support equitable access for these groups.

Szkoła w Koźlu-Rogach a racja stanu, czyli nowy słoń a sprawa polska

2013-05-28T15:01:02Z

Multistable processes and localizability

2013-05-28T14:01:03Z

Abstract: We use characteristic functions to construct alpha-multistable measures and integrals, where the measures behave locally like stable measures, but with the stability index alpha(x) varying with x. This enables us to construct alpha-multistable processes on R, that is processes whose scaling limit at time t is an alpha(t)-stable process. We present several examples of such multistable processes and examine their localisability.

Structure of the archaeal Cascade subunit Csa5 : Relating the small subunits of CRISPR effector complexes

2013-05-24T11:01:02Z

Abstract: The Cascade complex for CRISPR-mediated antiviral immunity uses CRISPR RNA (crRNA) to target invading DNA species from mobile elements such as viruses, leading to their destruction. The core of the Cascade effector complex consists of the Cas5 and Cas7 subunits, which are widely conserved in prokaryotes. Cas7 binds crRNA and forms the helical backbone of Cascade. Many archaea encode a version of the Cascade complex (denoted Type I-A) that includes a Csa5 (or small) subunit, which interacts weakly with the core proteins. Here, we report the crystal structure of the Csa5 protein from Sulfolobus solfataricus. Csa5 comprises a conserved α-helical domain with a small insertion consisting of a weakly conserved β-strand domain. In the crystal, the Csa5 monomers have multimerized into infinite helical threads. At each interface is a strictly conserved intersubunit salt bridge, deletion of which disrupts multimerization. Structural analysis indicates a shared evolutionary history among the small subunits of the CRISPR effector complexes. The same α-helical domain is found in the C-terminal domain of Cse2 (from Type I-E Cascade), while the N-terminal domain of Cse2 is found in Cmr5 of the CMR (Type III-B) effector complex. As Cmr5 shares no match with Csa5, two possibilities present themselves: selective domain loss from an ancestral Cse2 to create two new subfamilies or domain fusion of two separate families to create a new Cse2 family. A definitive answer awaits structural studies of further small subunits from other CRISPR effector complexes. Description: This work was funded by a grant from the Biotechnology and Biological Sciences Research Council (BBSRC) (REF: BB/G011400/1) to M.F.W. and J.H.N. and a BBSRC-funded studentship to J.R.

The genome of the obligate intracellular parasite Trachipleistophora hominis : new insights into microsporidian genome dynamics and reductive evolution

2013-06-02T04:01:01Z

Abstract: The dynamics of reductive genome evolution for eukaryotes living inside other eukaryotic cells are poorly understood compared to well-studied model systems involving obligate intracellular bacteria. Here we present 8.5 Mb of sequence from the genome of the microsporidian Trachipleistophora hominis, isolated from an HIV/AIDS patient, which is an outgroup to the smaller compacted-genome species that primarily inform ideas of evolutionary mode for these enormously successful obligate intracellular parasites. Our data provide detailed information on the gene content, genome architecture and intergenic regions of a larger microsporidian genome, while comparative analyses allowed us to infer genomic features and metabolism of the common ancestor of the species investigated. Gene length reduction and massive loss of metabolic capacity in the common ancestor was accompanied by the evolution of novel microsporidian-specific protein families, whose conservation among microsporidians, against a background of reductive evolution, suggests they may have important functions in their parasitic lifestyle. The ancestor had already lost many metabolic pathways but retained glycolysis and the pentose phosphate pathway to provide cytosolic ATP and reduced coenzymes, and it had a minimal mitochondrion (mitosome) making Fe-S clusters but not ATP. It possessed bacterial-like nucleotide transport proteins as a key innovation for stealing host-generated ATP, the machinery for RNAi, key elements of the early secretory pathway, canonical eukaryotic as well as microsporidian-specific regulatory elements, a diversity of repetitive and transposable elements, and relatively low average gene density. Microsporidian genome evolution thus appears to have proceeded in at least two major steps: an ancestral remodelling of the proteome upon transition to intracellular parasitism that involved reduction but also selective expansion, followed by a secondary compaction of genome architecture in some, but not all, lineages.

Fantasising the self, fantasising the other : memory and re-visions in Mario Martone's L'amore molesto

2013-05-21T11:31:01Z

“The ‘Ars vivendi’ of Laura Mañà’s Morir en San Hilario/To Die in San Hilario (2005)”

2013-05-21T08:31:02Z

Abstract: Over the past decade Spanish-Language Cinema has established itself beside Spanish and Latin American Cinema, and Morir en San Hilario is a good example of these new flexible collaborations rather than a strict transnational co-production. Billed as a comedy, the film could also be described as a variation on the road film, a circular journey to Utopia, a Spanish village/pueblo film, and a twenty-first-century ‘Ars moriendi’ developing the topos of ‘Homo viator’. This is not a frequent combination to be found on cinema screens and Laura Mañà’s gamble was to integrate these ingredients and create a fable to reflect on life and death. She does this through comedy, exaggerations, parody and a narrative style identified as magic realism. Her originality, however, overlaps with the lasting legacy of the fifteenth-century Castilian soldier-poet, Jorge Manrique (c.1440-1479) and his ‘Stanzas written upon the death of his father’, a landmark of Spanish Literature.

Two-dimensional magnetohydrodynamic turbulence in the limits of infinite and vanishing magnetic Prandtl number

2013-06-19T10:01:00Z

Abstract: We study both theoretically and numerically two-dimensional magnetohydrodynamic turbulence at infinite and zero magnetic Prandtl number $Pm$ (and the limits thereof), with an emphasis on solution regularity. For $Pm=0$, both $\norm{\omega}^2$ and $\norm{j}^2$, where $\omega$ and $j$ are, respectively, the vorticity and current, are uniformly bounded. Furthermore, $\norm{\nabla j}^2$ is integrable over $[0,\infty)$. The uniform boundedness of $\norm{\omega}^2$ implies that in the presence of vanishingly small viscosity $\nu$ (i.e. in the limit $Pm\to0$), the kinetic energy dissipation rate $\nu\norm{\omega}^2$ vanishes for all times $t$, including $t=\infty$. Furthermore, for sufficiently small $Pm$, this rate decreases linearly with $Pm$. This linear behaviour of $\nu\norm{\omega}^2$ is investigated and confirmed by high-resolution simulations with $Pm$ in the range $[1/64,1]$. Several criteria for solution regularity are established and numerically tested. As $Pm$ is decreased from unity, the ratio $\norm{\omega}_\infty/\norm{\omega}$ is observed to increase relatively slowly. This, together with the integrability of $\norm{\nabla j}^2$, suggests global regularity for $Pm=0$. When $Pm=\infty$, global regularity is secured when either $\norm{\nabla\u}_\infty/\norm{\omega}$, where $\u$ is the fluid velocity, or $\norm{j}_\infty/\norm{j}$ is bounded. The former is plausible given the presence of viscous effects for this case. Numerical results over the range $Pm\in[1,64]$ show that $\norm{\nabla\u}_\infty/\norm{\omega}$ varies slightly (with similar behaviour for $\norm{j}_\infty/\norm{j}$), thereby lending strong support for the possibility $\norm{\nabla\u}_\infty/\norm{\omega}<\infty$ in the limit $Pm\to\infty$. The peak of the magnetic energy dissipation rate $\mu\norm{j}^2$ is observed to decrease rapidly as $Pm$ is increased. This result suggests the possibility $\norm{j}^2<\infty$ in the limit $Pm\to\infty$. We discuss further evidence for the boundedness of the ratios $\norm{\omega}_\infty/\norm{\omega}$, $\norm{\nabla\u}_\infty/\norm{\omega}$ and $\norm{j}_\infty/\norm{j}$ in conjunction with observation on the density of filamentary structures in the vorticity, velocity gradient and current fields. Description: LAKB was supported by an EPSRC post-graduate studentship.

Note on solution regularity of the generalized magnetohydrodynamic equations with partial dissipation

2013-05-20T16:01:01Z

Abstract: In this brief note we study the $n$-dimensional magnetohydrodynamic equations with hyper-viscosity and zero resistivity. We prove global regularity of solutions when the hyper-viscosity is sufficiently strong.

The state of affairs : critical performativity and the online dating industry

2013-05-20T15:31:03Z

Abstract: In this paper we pursue a dialogue between Callon’s (1998) ‘performativity thesis’ and Critical Management Studies (CMS). We make use of the performativity thesis to elaborate on the construction of a market and the generation of calculative and rational economic agency in a specific empirical setting: the markets for relationships offered by dating services. We find evidence for ‘effective’ performativity, where technical processes and outcomes are shaped by academic theory. We link the performativity analysis with three critical perspectives: a novel enclosure in the commodification and sale of relationships; the politics of standardisation, classification, expertise and responsibility; and the enactment of instrumentally rational, self-interested social relations through the individualist assumptions of matching systems. We argue that a performativity analysis must begin with a critical politics: what kind of world would we like to see performed?

Solar magnetic carpet III : coronal modelling of synthetic magnetograms

2013-05-20T15:31:02Z

Teaching and understanding of quantum interpretations in modern physics courses

2013-05-20T15:01:04Z

Abstract: Just as expert physicists vary in their personal stances on interpretation in quantum mechanics, instructors vary on whether and how to teach interpretations of quantum phenomena in introductory modern physics courses. In this paper, we document variations in instructional approaches with respect to interpretation in two similar modern physics courses recently taught at the University of Colorado, and examine associated impacts on student perspectives regarding quantum physics. We find students are more likely to prefer realist interpretations of quantum-mechanical systems when instructors are less explicit in addressing student ontologies. We also observe contextual variations in student beliefs about quantum systems, indicating that instructors who choose to address questions of ontology in quantum mechanics should do so explicitly across a range of topics.

Refined characterization of student perspectives on quantum physics

2013-05-20T15:01:03Z

Abstract: The perspectives of introductory classical physics students can often negatively influence how those students later interpret quantum phenomena when taking an introductory course in modern physics. A detailed exploration of student perspectives on the interpretation of quantum physics is needed, both to characterize student understanding of physics concepts, and to inform how we might teach traditional content. Our previous investigations of student perspectives on quantum physics have indicated they can be highly nuanced, and may vary both within and across contexts. In order to better understand the contextual and often seemingly contradictory stances of students on matters of interpretation, we interviewed 19 students from four introductory modern physics courses taught at the University of Colorado. We find that students have attitudes and opinions that often parallel the stances of expert physicists when arguing for their favored interpretations of quantum mechanics, allowing for more nuanced characterizations of student perspectives in terms of three key interpretive themes. We present a framework for characterizing student perspectives on quantum mechanics, and demonstrate its utility in interpreting the sometimes contradictory nature of student responses to previous surveys. We further find that students most often vacillate in their responses when what makes intuitive sense to them is not in agreement with what they consider to be a correct response, underscoring the need to distinguish between the personal and the public perspectives of introductory modern physics students.

Coherent control of plasmonic nanoantennas using optical eigenmodes

2013-05-20T11:31:06Z

Abstract: The last decade has seen subwavelength focusing of the electromagnetic field in the proximity of nanoplasmonic structures with various designs. However, a shared issue is the spatial confinement of the field, which is mostly inflexible and limited to fixed locations determined by the geometry of the nanostructures, which hampers many applications. Here, we coherently address numerically and experimentally single and multiple plasmonic nanostructures chosen from a given array, resorting to the principle of optical eigenmodes. By decomposing the light field into optical eigenmodes, specifically tailored to the nanostructure, we create a subwavelength, selective and dynamic control of the incident light. The coherent control of plasmonic nanoantennas using this approach shows an almost zero crosstalk. This approach is applicable even in the presence of large transmission aberrations, such as present in holographic diffusers and multimode fibres. The method presents a paradigm shift for the addressing of plasmonic nanostructures by light.

Research-based course materials and assessments for upper-division electrodynamics (E&M II)

2013-05-16T11:31:03Z

Abstract: Favorable outcomes from ongoing research at the University of Colorado Boulder on student learning in junior-level electrostatics (E&M I) have led us to extend this work to upper-division electrodynamics (E&M II). We describe here our development of a set of research-based instructional materials designed to actively engage students during lecture (including clicker questions and other in-class activities); and an instrument for assessing whether our faculty-consensus learning goals are being met. We also discuss preliminary results from several recent implementations of our transformed curriculum, plans for the dissemination and further refinement of these materials, and offer some insights into student difficulties in advanced undergraduate electromagnetism.

Development of quantum perspectives in modern physics

2013-05-16T11:31:01Z

Abstract: Introductory undergraduate courses in classical physics stress a perspective that can be characterized as realist; from this perspective, all physical properties of a classical system can be simultaneously specified and thus determined at all future times. Such a perspective can be problematic for introductory quantum physics students, who must develop new perspectives in order to properly interpret what it means to have knowledge of quantum systems. We document this evolution in student thinking in part through pre- and post-instruction evaluations using the Colorado Learning Attitudes about Science Survey. We further characterize variations in student epistemic and ontological commitments by examining responses to two essay questions, coupled with responses to supplemental quantum attitude statements. We find that, after instruction in modern physics, many students are still exhibiting a realist perspective in contexts where a quantum-mechanical perspective is needed. We further find that this effect can be significantly influenced by instruction, where we observe variations for courses with differing learning goals. We also note that students generally do not employ either a realist or a quantum perspective in a consistent manner.

Interpretive themes in quantum physics : curriculum development and outcomes

2013-05-16T07:31:02Z

Abstract: A common learning goal for modern physics instructors is for students to recognize a difference between the experimental uncertainty of classical physics and the fundamental uncertainty of quantum mechanics. Our prior work has shown that student perspectives on the physical interpretation of quantum mechanics can be characterized, and are differentially influenced by the myriad ways instructors approach interpretive themes in their introductory courses. We report how a transformed modern physics curriculum (recently implemented at the University of Colorado) has positively impacted student perspectives on quantum physics, by making questions of classical and quantum reality a central theme of the course, but also by making the beliefs of students (and not just those of scientists) an explicit topic of discussion.

Interpretation in quantum physics as hidden curriculum

2013-05-15T21:31:01Z

Abstract: Prior research has demonstrated how the realist perspectives of classical physics students can translate into specific beliefs about quantum phenomena when taking an introductory modern physics course. Student beliefs regarding the interpretation of quantum mechanics often vary by context, and are most often in alignment with instructional goals in topic areas where instructors are explicit in promoting a particular perspective. Moreover, students are more likely to maintain realist perspectives in topic areas where instructors are less explicit in addressing interpretive themes, thereby making such issues part of a hidden curriculum. We discuss various approaches to addressing student perspectives and interpretive themes in a modern physics course, and explore the associated impacts on student thinking.

Student perspectives in quantum physics

2013-05-15T21:01:08Z

Abstract: Introductory courses in classical physics are promoting in students a realist perspective, made up in part by the belief that all physical properties of a system can be simultaneously specified, and thus determined at all future times. Such a perspective can be problematic for introductory quantum physics students, who must develop new framings of epistemic and ontological resources in order to properly interpret what it means to have knowledge of quantum systems. We document this evolution in student thinking in part through pre/post instruction evaluations using the CLASS attitude survey. We further characterize variations in student epistemic and ontological commitments by examining responses to an essay question, coupled with responses to supplemental quantum attitude statements. We find that, after instruction in modern physics, many students are still exhibiting a realist perspective in contexts where a quantum perspective is needed. We also find that this effect can be significantly influenced by instruction, where we observe variations for courses with differing learning goals.

Quantum interpretations in modern physics instruction

2013-05-15T21:01:07Z

Abstract: Just as expert physicists vary in their personal stances on interpretation in quantum mechanics, instructors hold different views on teaching interpretations of quantum phenomena in introductory modern physics courses. There has been relatively little research in the physics education community on the variation in instructional approaches with respect to quantum interpretation, and how instructional choices impact student thinking. We compare two modern physics courses taught at the University of Colorado with similar learning environments, but where the instructors held different views on how to teach students about interpretations of quantum processes. We find significant differences in how students from these two courses responded to a survey on their beliefs about quantum mechanics; findings also suggest that instructors who choose to address student ontologies should do so across a range of topics.

El pronunciamiento mexicano del siglo XIX. Hacia una nueva tipología

2013-05-12T02:32:03Z

Abstract: Tras la guerra de Independencia (1810-1821) estallaron más de 1 500 pronunciamientos entre el Plan de Iguala de 1821 y el Plan de Tuxtepec de 1876. En varios casos degeneraron en enfrentamientos de una violencia atroz como el saqueo del Parián en la ciudad de México de 1828. En otros resultaron en guerras civiles brutales (1832, 1854-1855, 1858-1860). En muchos casos, sin embargo, sus demandas fueron atendidas o sofocadas dependiendo de cuántos pronunciamientos de adhesión recibieron. Este artículo busca redefinir la práctica del pronunciamiento en México, haciendo hincapié en el protagonismo que tuvieron grupos e instituciones civiles al adoptar este medio legítimo, aunque no constitucional, para forzar cambios políticos tanto a nivel regional como nacional durante las primeras décadas nacionales.

Primi influssi culturali italo-veneti sull'inglese : la testimonianza dei venezianismi in Florio, Coryate e Jonson

2013-05-10T20:31:01Z

Abstract: This article demonstates that the earliest body of Italianisms in English, in the sixteenth and early seventeenth centuries, was in large measure of Venetian origin. After establishing and dating the fifty Venetianisms that entered English in this period the study goes on to analyse Venetian lexical influence in John Florio's Italian-English dictionaries (1598 and 1611), in Thomas Coryate's travel book (the "Crudities") (1611) and in Ben Jonson's play "Volpone" (1607) set in Venice.

Double time : Facing the future in migration’s past

2013-05-10T19:31:03Z

Abstract: Interpretations of Italian films about migration tend to refer to the historical experience of emigration or of colonialism as the historical coordinates through which these films are best understood. This article looks at four recent films featuring migrants in prominent roles that appear to elide such an interpretive framework. While the past and its intrusive effects do feature strongly in these films, it is difficult to produce a predictable linear and causal narrative that would link past, present, and future in predictable ways. Stylistically, the four films also represent a notable move away from the realist political agenda and aesthetic that has tended to dominate Italian film production on the topic of migration. This article argues that their adoption of the features that recall those of film noir (in its Italian manifestation) suggests a new range of thematic and social concerns that refer as much to possible futures as well as known pasts. There is a particular focus on the topic of bodily reproduction which is no longer limited to the sphere of the sexual. The opportunities offered by technology for the body to reproduce in new ways alters the parameters of how the nation might be imagined.

Perceptions of France : French books in the early libraries of South Australia, 1848-1884

2013-05-10T19:31:01Z

Abstract: In 1848, the South Australian Library and Mechanics’ Institute came into existence. It was the first stable library in South Australia. In 1856 its books passed to the library of the South Australian Institute, whose holdings continued to grow until 1883, when many of the books were transferred to the fledgling Public Library, forerunner of today’s State Library. Between 1848 and 1883 the two early libraries built up a collection of nearly 20,000 works of which a little over 500 were by French authors, and almost half of those books were in French. This paper follows the growth of the collection of French books and examines the nature of the books that were acquired. In doing so it highlights the place which French culture continued to occupy within the intellectual life of early South Australia and illustrates the gradual change of taste as an elite culture was displaced by the demands of a more popular readership.

Scotland for Franco : Charles Saroléa v. The Red Duchess

2013-05-10T19:01:03Z

What counts as good evidence

2013-05-10T17:01:04Z

Abstract: Making better use of evidence is essential if public services are to deliver more for less. Central to this challenge is the need for a clearer understanding about standards of evidence that can be applied to the research informing social policy. This paper reviews the extent to which it is possible to reach a workable consensus on ways of identifying and labelling evidence. It does this by exploring the efforts made to date and the debates that have ensued. Throughout, the focus is on evidence that is underpinned by research, rather than other sources of evidence such as expert opinion or stakeholder views.

Henry Hallam revisited

2013-05-12T04:36:34Z

Abstract: Although Henry Hallam (1777–1859) is best known for his Constitutional History of England (1827) and as a founder of ‘whig’ history, to situate him primarily as a mere critic of David Hume or as an apprentice to Thomas Babington Macaulay does him a disservice. He wrote four substantial books of which the first, his View of the state of Europe during the middle ages (1818), deserves to be seen as the most important; and his correspondence shows him to have been integrated into the contemporary intelligentsia in ways that imply more than the Whig acolyte customarily portrayed by commentators. This article re-situates Hallam by thinking across both time and space and depicts a significant historian whose filiations reached to Europe and North America. It proposes that Hallam did not originate the whig interpretation of history but rather that he created a sense of the past resting on law and science which would be reasserted in the age of Darwin.

Constructing the retail investor : performativity and power in the market for investment services

2013-05-09T16:31:17Z

Abstract: This paper examines retail investment as a practice performed by marketing knowledge and highlights the power effects of market devices. Using a qualitative study of retail investors in the United Kingdom, it considers the devices and discourses that structure investment behaviour. It draws attention to parallels between the precepts of the market studies programme and the Foucauldian literature of governance technologies in neo-liberal capitalism. Market devices and heterodox ways of understanding the financial market constitute investors as docile consumers of investment services. Self-discipline and confession are normalising technologies that help investors cope with difficulties and losses in the market.

Structural insights into the mechanism and inhibition of the beta-Hydroxydecanoyl-Acyl carrier protein dehydratase from pseudomonas aeruginosa

2013-05-03T13:01:03Z

Abstract: Fatty acid biosynthesis is an essential component of metabolism in both eukaryotes and prokaryotes. The fatty acid biosynthetic pathway of Gram-negative bacteria is an established therapeutic target. Two homologous enzymes FabA and FabZ catalyze a key step in fatty acid biosynthesis; both dehydrate hydroxyacyl fatty acids that are coupled via a phosphopantetheine to an acyl carrier protein (ACP). The resulting trans-2-enoyl-ACP is further polymerized in a processive manner. FabA, however, carries out a second reaction involving isomerization of trans-2-enoyl fatty acid to cis-3-enoyl fatty acid. We have solved the structure of Pseudomonas aeruginosa FabA with a substrate allowing detailed molecular insight into the interactions of the active site. This has allowed a detailed examination of the factors governing the second catalytic step. We have also determined the structure of FabA in complex with small molecules (so-called fragments). These small molecules occupy distinct regions of the active site and form the basis for a rational inhibitor design program. (C) 2012 Elsevier Ltd. All rights reserved.

Mechanistic insights into the triazolylidene-catalysed Stetter and benzoin reactions : role of the N-aryl substituent

2013-05-03T12:31:02Z

Abstract: The in situ observation, isolation and reversible formation of intermediate 3-(hydroxybenzyl) azolium salts derived from NHC addition to a range of substituted benzaldehydes is probed. Equilibrium constants for the formation of these 3-(hydroxybenzyl) azolium salts, as well as rate constants of hydrogen-deuterium exchange (k(ex)) at C(alpha) of these intermediates for a range of N-aryl triazolinylidenes is reported. These combined studies give insight into the preference of N-pentafluorophenyl NHCs to participate in benzoin and Stetter reaction processes.

An efficient route for the synthesis of phosphorus-selenium macro-heterocycles

2013-05-03T12:01:02Z

Abstract: Four-membered ring [PhP(Se)(mu-Se)](2) (Woollins' reagent, WR) reacts with disodium alkenyl-diols followed by in situ ring-closure reaction with appropriate dibromoalkanes affording a series of unusual nine-to fifteen-membered organoselenophosphorus macrocycles bearing the O-P-Se-C-n-Se-P-O or O-P-Se-C-n-O-P-Se linkage.

Violets and abolition : The discourse on slavery in Faustina Saez de Melgar's magazine La Violeta (1862-1866)

2013-05-12T04:08:34Z

Abstract: Although the commitment of several nineteenth-century Spanish women writers to abolitionism is a well-established fact, not much is known about the concrete forms their engagement took in a society in which the bourgeois ideology of woman as the angel in the house played a prominent role. The close study of the weekly magazine La Violeta (1862-66), directed by Faustina Sáez de Melgar, shows how the active and public support for this international cause was linked to the development of a model of compassionate intervention by women, most notably formulated by the magazine's regular contributor Rogelia León in response to the very mixed reviews of the foundational meeting of a ladies' abolitionist society. The press coverage of this event clearly demonstrates how political conflict is cast in terms of gender and class and used to threaten middle-class women who step into the political sphere. The analysis of the discourse on slavery reveals an equal importance of both categories in La Violeta, together with the patronising and casual racism of its authors.

The privilege of poverty. Clare of Assisi, Agnes of Prague, and the struggle for a Franciscan rule for women

2013-05-03T09:01:07Z

Living like the laity? The negotiation of religious status in the cities of late medieval Italy

2013-05-12T02:05:17Z

Abstract: Framed by consideration of images of treasurers on the books of the treasury in thirteenth-century Siena, this article uses evidence for the employment of men of religion in city offices in central and northern Italy to show how religious status (treated as a subset of ‘clerical culture’) could become an important object of negotiation between city and churchmen, a tool in the repertoire of power relations. It focuses on the employment of men of religion as urban treasurers and takes Florence in the late thirteenth and early fourteenth centuries as a principal case study, but also touches on the other tasks assigned to men of religion and, very briefly, on evidence from other cities (Bologna, Brescia, Como, Milan, Padua, Perugia and Siena). It outlines some of the possible arguments deployed for this use of men of religion in order to demonstrate that religious status was, like gender, more contingent and fluid than the norm-based models often relied on as a shorthand by historians. Despite the powerful rhetoric of lay–clerical separation in this period, the engagement of men of religion in paid, term-bound urban offices inevitably brought them closer to living like the laity.

Models incorporating chromatin modification data identify functionally important p53 binding sites

2013-05-01T15:01:03Z

Abstract: Genome-wide prediction of transcription factor binding sites is notoriously difficult. We have developed and applied a logistic regression approach for prediction of binding sites for the p53 transcription factor that incorporates sequence information and chromatin modification data. We tested this by comparison of predicted sites with known binding sites defined by chromatin immunoprecipitation (ChIP), by the location of predictions relative to genes, by the function of nearby genes and by analysis of gene expression data after p53 activation. We compared the predictions made by our novel model with predictions based only on matches to a sequence position weight matrix (PWM). In whole genome assays, the fraction of known sites identified by the two models was similar, suggesting that there was little to be gained from including chromatin modification data. In contrast, there were highly significant and biologically relevant differences between the two models in the location of the predicted binding sites relative to genes, in the function of nearby genes and in the responsiveness of nearby genes to p53 activation. We propose that these contradictory results can be explained by PWM and ChIP data reflecting primarily biophysical properties of protein–DNA interactions, whereas chromatin modification data capture biologically important functional information.

Short and long supports for constraint propagation

2013-05-01T09:31:02Z

Abstract: Special-purpose constraint propagation algorithms frequently make implicit use of short supports -- by examining a subset of the variables, they can infer support (a justification that a variable-value pair may still form part of an assignment that satisfies the constraint) for all other variables and values and save substantial work -- but short supports have not been studied in their own right. The two main contributions of this paper are the identification of short supports as important for constraint propagation, and the introduction of HaggisGAC, an efficient and effective general purpose propagation algorithm for exploiting short supports. Given the complexity of HaggisGAC, we present it as an optimised version of a simpler algorithm ShortGAC. Although experiments demonstrate the efficiency of ShortGAC compared with other general-purpose propagation algorithms where a compact set of short supports is available, we show theoretically and experimentally that HaggisGAC is even better. We also find that HaggisGAC performs better than GAC-Schema on full-length supports. We also introduce a variant algorithm HaggisGAC-Stable, which is adapted to avoid work on backtracking and in some cases can be faster and have significant reductions in memory use. All the proposed algorithms are excellent for propagating disjunctions of constraints. In all experiments with disjunctions we found our algorithms to be faster than Constructive Or and GAC-Schema by at least an order of magnitude, and up to three orders of magnitude.

Decadal-interdecadal climate variability over Antarctica and linkages to the tropics : analysis of ice core, instrumental, and tropical proxy data

2013-04-30T23:22:18Z

Abstract: The Antarctic continent contains the majority of the global ice volume and plays an important role in a changing climate. The nature and causes of Antarctic climate variability are, however, poorly understood beyond interannual time scales due to the paucity of long, reliable meteorological observations. This study analyzes decadal-interdecadal climate variability over Antarctica using a network of annually resolved ice core records and various instrumental and tropical proxy data for the 19th and 20th centuries. During the 20th century, Antarctic ice core records indicate strong linkages to sea surface temperature (SST) variations in the tropical Pacific and Atlantic on decadal-interdecadal time scales. Antarctic surface temperature anomalies inferred from the ice cores are consistent with the associated changes in atmospheric circulation and thermal advection. A set of atmospheric general circulation model experiments supports the idea that decadal SST variations in the tropics force atmospheric teleconnections that affect Antarctic surface temperatures. When coral and other proxies for tropical climate are used to extend the analysis back to 1799, a similar Antarctic-tropical Pacific linkage is found, with evidence for a weaker connection during the first half of the 19th century. Over the past 50 years, a change in the phase of Pacific and Atlantic interdecadal variability may have contributed to the rapid warming of the Antarctic Peninsula and West Antarctica.

Stressed but stable : Canopy loss decreased species synchrony and metabolic variability in an intertidal hard-bottom community

2013-04-28T13:31:02Z

Abstract: The temporal stability of aggregate community properties depends on the dynamics of the component species. Since species growth can compensate for the decline of other species, synchronous species dynamics can maintain stability (i.e. invariability) in aggregate properties such as community abundance and metabolism. In field experiments we tested the separate and interactive effects of two stressors associated with storminess–loss of a canopy-forming species and mechanical disturbances–on species synchrony and community respiration of intertidal hard-bottom communities on Helgoland Island, NE Atlantic. Treatments consisted of regular removal of the canopy-forming seaweed Fucus serratus and a mechanical disturbance applied once at the onset of the experiment in March 2006. The level of synchrony in species abundances was assessed from estimates of species percentage cover every three months until September 2007. Experiments at two sites consistently showed that canopy loss significantly reduced species synchrony. Mechanical disturbance had neither separate nor interactive effects on species synchrony. Accordingly, in situ measurements of CO2-fluxes showed that canopy loss, but not mechanical disturbances, significantly reduced net primary productivity and temporal variation in community respiration during emersion periods. Our results support the idea that compensatory dynamics may stabilise aggregate properties. They further suggest that the ecological consequences of the loss of a single structurally important species may be stronger than those derived from smaller-scale mechanical disturbances in natural ecosystems.

Multi-task research and research joint ventures

2013-04-26T09:01:03Z

Abstract: The paper shows that, whenever the completion of a research project requires the overcoming of more than one research obstacle, then Research Joint Ventures enjoy an intrinsic advantage relative to independent firms. This advantage, which has hitherto escaped attention in the RJV literature, relates to the RJV’s ability to organize research more efficiently than independent firms. The fact that RJVs can be both more profitable and yield higher expected net welfare than independent firms is surprising because it is derived from a model in which RJVs do not optimize over R&D investment. The paper exploits a basic result in systems reliability theory to establish the organizational superiority of RJVs.

Estimating animal population density using passive acoustics

2013-04-26T08:31:02Z

Abstract: Reliable estimation of the size or density of wild animal populations is very important for effective wildlife management, conservation and ecology. Currently, the most widely used methods for obtaining such estimates involve either sighting animals from transect lines or some form of capture-recapture on marked or uniquely identifiable individuals. However, many species are difficult to sight, and cannot be easily marked or recaptured. Some of these species produce readily identifiable sounds, providing an opportunity to use passive acoustic data to estimate animal density. In addition, even for species for which other visually based methods are feasible, passive acoustic methods offer the potential for greater detection ranges in some environments (e.g. underwater or in dense forest), and hence potentially better precision. Automated data collection means that surveys can take place at times and in places where it would be too expensive or dangerous to send human observers. Here, we present an overview of animal density estimation using passive acoustic data, a relatively new and fast-developing field. We review the types of data and methodological approaches currently available to researchers and we provide a framework for acoustics-based density estimation, illustrated with examples from real-world case studies. We mention moving sensor platforms (e.g. towed acoustics), but then focus on methods involving sensors at fixed locations, particularly hydrophones to survey marine mammals, as acoustic-based density estimation research to date has been concentrated in this area. Primary among these are methods based on distance sampling and spatially explicit capture-recapture. The methods are also applicable to other aquatic and terrestrial sound-producing taxa. We conclude that, despite being in its infancy, density estimation based on passive acoustic data likely will become an important method for surveying a number of diverse taxa, such as sea mammals, fish, birds, amphibians, and insects, especially in situations where inferences are required over long periods of time. There is considerable work ahead, with several potentially fruitful research areas, including the development of (i) hardware and software for data acquisition, (ii) efficient, calibrated, automated detection and classification systems, and (iii) statistical approaches optimized for this application. Further, survey design will need to be developed, and research is needed on the acoustic behaviour of target species. Fundamental research on vocalization rates and group sizes, and the relation between these and other factors such as season or behaviour state, is critical. Evaluation of the methods under known density scenarios will be important for empirically validating the approaches presented here

Evolutionary origins of human handedness : evaluating contrasting hypotheses

2013-04-24T16:01:02Z

Abstract: Variation in methods and measures, resulting in past dispute over the existence of population handedness in nonhuman great apes, has impeded progress into the origins of human right-handedness and how it relates to the human hallmark of language. Pooling evidence from behavioral studies, neuroimaging and neuroanatomy, we evaluate data on manual and cerebral laterality in humans and other apes engaged in a range of manipulative tasks and in gestural communication. A simplistic human/animal partition is no longer tenable, and we review four (nonexclusive) possible drivers for the origin of population-level right-handedness: skilled manipulative activity, as in tool use; communicative gestures; organizational complexity of action, in particular hierarchical structure; and the role of intentionality in goal-directed action. Fully testing these hypotheses will require developmental and evolutionary evidence as well as modern neuroimaging data.

Estimating prevalence of injecting drug users and associated heroin-related death rates in England by using regional data and incorporating prior information

2013-04-24T14:31:03Z

Abstract: Injecting drug users (IDUs) have a direct social and economic effect yet can typically be regarded as a hidden population within a community. We estimate the size of the IDU population across the nine different Government Office regions of England in 2005–2006 by using capture–recapture methods with age (ranging from 15 to 64 years) and gender as covariate information. We consider a Bayesian model averaging approach using log-linear models, where we can include explicit prior information within the analysis in relation to the total IDU population (elicited from the number of drug-related deaths and injectors’ drug-related death rates). Estimation at the regional level allows for regional heterogeneity with these regional estimates aggregated to obtain a posterior mean estimate for the number of England's IDUs of 195840 with 95% credible interval (181700, 210480). There is significant variation in the estimated regional prevalence of current IDUs per million of population aged 15–64 years, and in injecting drug-related death rates across the gender × age cross-classifications. The propensity of an IDU to be seen by at least one source also exhibits strong regional variability with London having the lowest propensity of being observed (posterior mean probability 0.21) and the South West the highest propensity (posterior mean 0.46).

Paradoxical consequences of prohibitions

2013-05-28T14:31:00Z

Abstract: Explanations based in attribution theory claim that strong external controls such as parental restrictiveness and punishment undermine moral internalization. In contrast, three studies provide evidence that parental punishment does socialize morality, but of a particular sort: a morality focused on prohibitions (i.e., proscriptive orientation), rather than positive obligations (i.e., prescriptive orientation). Study 1 found young adults’ accounts of parental restrictiveness and punishment activated their sensitivity to prohibitions and predicted a proscriptive orientation. Consistent with the greater potency of temptations for proscriptively-oriented children, as well as past research linking shame to proscriptive morality, Study 2 found that restrictive parenting was also associated with greater suppression of temptations. Finally, Studies 3a and 3b found that suppressing these immoral thoughts is paradoxically harder for those with strong proscriptive orientations; more specifically, priming a proscriptive (versus prescriptive) orientation and inducing mental suppression of “immoral” thoughts led to the most ego depletion for those with restrictive parents. Overall, individuals who had restrictive parents had the lowest self-regulatory ability to resist their “immoral” temptations after prohibitions were activated. In contrast to common attributional explanations, these studies suggest that harsh external control by parents does not undercut moral socialization, but rather undermines individuals’ ability to resist temptation.

The traitor as patriot : Guy Burgess, Englishness and camp in Another Country and An Englishman Abroad

2013-04-24T13:31:02Z

Abstract: This article focuses on the representation of the spy Guy Burgess, one of the famous Cambridge ring, in two very successful British heritage films, An Englishman Abroad (John Schlesinger, UK, 1983) and Another Country (Marek Kanievska, UK, 1984). The article argues that the films rely on popular notions of Englishness as politically safe and non-extremist, thus fabricating a view of the past that misrepresents Burgess in the effort to normalize him. Similarly, stereotypical views of gay men as frivolous and non-ideological are amply exploited in the films' portrayal of their protagonist. Burgess's upper-class English roots are used to package him as part of the heritage experience, while his homosexuality is not only presented as the reason for spying, but it is also constructed as a camp performance, effectively defusing the threat of ideological commitment and political betrayal. The radical, lethal and devoutly Marxist Burgess is thus stripped of his ideology and turned into a safe national icon.

Near-infrared spectroscopy study of tourniquet-induced forearm ischaemia in patients with coronary artery disease

2013-05-12T04:15:36Z

Abstract: Near-Infrared Spectroscopy (NIR) can be employed to monitor local changes in haemodynamics and oxygenation of human tissues. A preliminary study has been performed in order to evaluate the NIRS transmittance response to induced forearm ischaemia in patients with coronary artery disease (CAD). The population consists in 40 patients with cardiovascular risk factors and angiographically documented CAD, compared to a group of 13 normal subjects. By inflating and subsequently deflating a cuff placed around the patient arm, an ischaemia has been induced and released, and the patients have been observed until recovery of the basal conditions. A custom LAIRS spectrometer (IRIS) has been used to collect the backscattered light intensities from the patient forearm throughout the ischaemic and the recovery phase. The time dependence of the near-infrared transmittance on the control group is consistent with the available literature. On the contrary, the magnitude and dynamics of the NIRS signal on the CAD patients show deviations from the documented normal behavior, which can be tentatively attributed to abnormal vessel stiffness. These preliminary results, while validating the performance of the IRIS spectrometer, are strongly conducive towards the applicability of the NIRS technique to ischaemia analysis and to endothelial dysfunction characterization in CAD patients with cardiovascular risk factors.

Tissue surface as the reference arm in Fourier domain optical coherence tomography

2013-05-26T00:35:00Z

Abstract: We present a simple method applicable to common-path Fourier domain optical coherence tomography (OCT) in which the tissue surface is used as the reference arm. We propose using aluminium hydroxide powder as a potential tissue surface diffuser to allow wider application of this method. This technique allows one to avoid placing a reference arm reflective element, such as glass plate, on tissue, and intrinsically avoids both coherent and complex conjugate mirror artifacts associated with glass plates. Aluminium hydroxide can be sprayed onto tissue using spray nozzles commonly found in endoscopes. The sensitivity of the tissue reference arm common-path OCT image is 94 dB for a 50-mu s charge-coupled device integration time, and 97.5 dB for a 200-mu s CCD integration time. (C) 2012 Society of Photo-Optical Instrumentation Engineers (SPIE). [DOL 10.1117/1.JBO.17.7.071305]

A hybrid organic semiconductor/silicon photodiode for efficient ultraviolet photodetection

2013-05-26T00:34:28Z

Abstract: A method employing conjugated polymer thin film blends is shown to provide a simple and convenient way of greatly enhancing the ultraviolet response of silicon photodetectors. Hybrid organic semiconductor/silicon photodetectors are demonstrated using fluorene copolymers and give a quantum efficiency of 60% at 200 nm. The quantum efficiency is greater than 34% over the entire 200-620 nm range. These devices show promise for use in high sensitivity, low cost UV-visible photodetection and imaging applications. (C) 2007 Optical Society of America

Memorability of pre-designed and user-defined gesture sets

2013-04-18T09:01:02Z

The Letter of the law : literacy and orality in S. A. Panov's Murder in Medveditsa Village

2013-05-12T02:32:02Z

Abstract: This article takes as its subject a nineteenth-century detective story: S.A. Panov’s Murder in Medveditsa Village (1872). Panov’s work is remarkable amongst its contemporaries for the way in which it interrogates the relative authority of the written and the spoken word in the criminal investigation and, in so doing, foregrounds the role and status that detective fiction assigns to language. The aim of the present article is to discuss the ambiguously nuanced illustration Panov provides of the relative power of written, spoken and non-verbal language in the particular context of the functioning of the law and the pursuit of the ‘truth’, two cornerstones of detective fiction. Language, and especially the written word, is thus shown to play the decisive role in structuring the various networks of authority operating in and around the fictional world.

Paul Valéry and the search for poetic rhythm

2013-05-12T02:04:57Z

Abstract: Throughout his theoretical writings, Valéry insists on two fundamental principles: poetic rhythm is undefinable and yet it is central to poetry. Although his verse practice evolves from irregularity to regularity, Valéry insists that predictable metrical forms are no guarantee of poeticity, and rejects the Romantic model of rhythmic mimesis based on the cosmos, nature or the human body. It is not by confirming the meaningfulness of regular patterns, therefore, that poetic rhythm signifies; rather, the complex overlapping of multiple, elusive and unanalysable rhythms provides a source of questions to which the answer is constantly deferred; and that, for Valéry, is the definition of poetry.

Variation in sexual dimorphism and assortative mating do not predict genetic divergence in the sexually dimorphic Goodeid fish Girardinichthys multiradiatus

2013-04-17T10:01:02Z

Abstract: Sexual dimorphism is often used as a proxy for the intensity of sexual selection in comparative studies of sexual selection and diversification. The Mexican Goodeinae are a group of livebearing freshwater fishes with large variation between species in sexual dimorphism in body shape. Previously we found an association between variation in morphological sexual dimorphism between species and the amount of gene flow within populations in the Goodeinae. Here we have examined if morphological differentiation within a single dimorphic species is related to assortative mating or gene flow between populations. In the Amarillo fish Girardinichthys multiradiatus studies have shown that exaggerated male fins are targets of female preferences. We find that populations of the species differ in the level of sexual dimorphism displayed due to faster evolution of differences in male than female morphology. However, this does not predict variation in assortative mating tests in the laboratory; in fact differences in male morphology are negatively correlated with assortative mating. Microsatellite markers reveal significant genetic differences between populations. However, gene flow is not predicted by either morphological differences or assortative mating. Rather, it demonstrates a pattern of isolation by distance with greater differentiation between watersheds. We discuss the caveats of predicting behavioural and genetic divergence from so-called proxies of sexual selection [Current Zoology 58 (3): 440-452, 2012].

Measuring the effect of the reflection of sound from the lips in brass musical instruments

2013-04-17T09:31:03Z

Abstract: The lips of the player are often assumed to perfectly reflect sounds that strike them. Experimental and theoretical calculations of input impedance demonstrate the pressure that would build up if a flat, perfectly reflecting volume velocity source were used to excite the air into vibration. In reality the lips should project slightly into the instrument mouthpiece and absorb a small amount of the energy that strikes them and this study will quantify this effect using wave separation/impedance apparatus. For closed lips it is expected that the strength of resonances will be reduced, but that the correction will be small. The condition for reflection from lips that are not fully closed will differ more significantly from perfect reflection and it is anticipated that this data will be useful for integration into physical models of brass instruments.

Non-linear dynamics of a driven nanomechanical single electron transistor

2013-04-17T09:31:02Z

Abstract: We analyze the response of a nanomechanical resonator to an external drive when it is also coupled to a single-electron transistor (SET). The interaction between the SET electrons and the mechanical resonator depends on the amplitude of the mechanical motion leading to a strongly non-linear response to the drive which is similar to that of a Duffing oscillator. We show that the average dynamics of the resonator is well-described by a simple effective model which incorporates damping and frequency renormalization terms which are amplitude dependent. We also find that for a certain range of parameters the system displays interesting bistable dynamics in which noise arising from charge fluctuations causes the resonator to switch slowly between different dynamical states. Description: This work was supported by EPSRC [Grant number EP/I017818/1]

Decomposition tables for experiments. II. Two–one randomizations

2013-04-15T14:01:04Z

Abstract: We investigate structure for pairs of randomizations that do not follow each other in a chain. These are unrandomized-inclusive, independent, coincident or double randomizations. This involves taking several structures that satisfy particular relations and combining them to form the appropriate orthogonal decomposition of the data space for the experiment. We show how to establish the decomposition table giving the sources of variation, their relationships and their degrees of freedom, so that competing designs can be evaluated. This leads to recommendations for when the different types of multiple randomization should be used.

Decomposition tables for experiments I. A chain of randomizations

2013-04-15T14:01:03Z

Abstract: One aspect of evaluating the design for an experiment is the discovery of the relationships between subspaces of the data space. Initially we establish the notation and methods for evaluating an experiment with a single randomization. Starting with two structures, or orthogonal decompositions of the data space, we describe how to combine them to form the overall decomposition for a single-randomization experiment that is "structure balanced." The relationships between the two structures are characterized using efficiency factors. The decomposition is encapsulated in a decomposition table. Then, for experiments that involve multiple randomizations forming a chain, we take several structures that pairwise are structure balanced and combine them to establish the form of the orthogonal decomposition for the experiment. In particular, it is proven that the properties of the design for Such an experiment are derived in a straightforward manner from those of the individual designs. We show how to formulate an extended decomposition table giving the sources of variation, their relationships and their degrees of freedom, so that competing designs can be evaluated.

Buying biosafety - is the price right?

2013-04-15T13:31:02Z

Willin, an upstream component of the Hippo signaling pathway, orchestrates mammalian peripheral nerve fibroblasts

2013-06-02T00:31:51Z

Abstract: Willin/FRMD6 was first identified in the rat sciatic nerve, which is composed of neurons, Schwann cells, and fibroblasts. Willin is an upstream component of the Hippo signaling pathway, which results in the inactivation of the transcriptional coactivator YAP through Ser127 phosphorylation. This in turn suppresses the expression of genes involved in cell growth, proliferation and cancer development ensuring the control of organ size, cell contact inhibition and apoptosis. Here we show that in the mammalian sciatic nerve, Willin is predominantly expressed in fibroblasts and that Willin expression activates the Hippo signaling cascade and induces YAP translocation from the nucleus to the cytoplasm. In addition within these cells, although it inhibits cellular proliferation, Willin expression induces a quicker directional migration towards scratch closure and an increased expression of factors linked to nerve regeneration. These results show that Willin modulates sciatic nerve fibroblast activity indicating that Willin may have a potential role in the regeneration of the peripheral nervous system.

Embodiment in the war film : Paradise Now and The Hurt Locker

2013-04-10T11:31:03Z

Abstract: In this article I compare two recent films that foreground the body at risk in the new wars of the twenty-first century. Paradise Now (Abu-Assad, 2005) and The Hurt Locker (Bigelow, 2008) convey the subject of the body in war from what would seem to be opposing perspectives, the first representing the experience of a resistance fighter, a suicide bomber in present-day Palestine, and the latter rendering the perceptions of a US soldier, the leader of a bomb disposal squad in Iraq. Seeming opposites, antitheses of each other, the two protagonists and the two films can be set face to face in a way that brings the changing nature of modern war into frame. No longer defined by the ideology of total war that shaped the grand narratives of twentieth-century combat, the new imagery of war and resistance, of insurgency and counter-insurgency, is crystallized here in a new symbolic iteration of the body at risk.

Development of a contact call in black-capped chickadees (Poecile atricapillus) hand-reared in different acoustic environments

2013-04-06T20:31:02Z

Abstract: The tseet contact call, common to black-capped (Poecile atricapillus) and mountain chickadees (P. gambeli), is the most frequently produced vocalization of each species. Previous work has characterized the tseet call of black-capped and mountain chickadees from different geographic locations in terms of nine acoustic features. In the current study, using similar methods, the tseet call of black-capped chickadees that were hand reared with either conspecifics, heterospecifics (mountain chickadees), or in isolation from adult chickadees are described. Analysis of call features examined which acoustic features were most affected by rearing environment, and revealed that starting frequency and the slope of the descending portion of the tseet call differed between black-capped chickadees reared with either conspecific or heterospecific adults. Birds reared in isolation from adults differed from the other hand-reared groups on almost every acoustic feature. Chickadee tseet calls are more individualized when they are reared with adult conspecifics or heterospecifics compared to chickadees that are reared in isolation from adults. The current results suggest a role of learning in this commonly used contact call.

The theory and practice of narrative in Plato

2013-04-05T09:31:01Z

Man and boy : Montgomery Clift as a queer star in Wild River

2013-05-12T03:32:55Z

Abstract: Montgomery Clift has been underexplored by film scholars, who have mostly focused on his early career. This article uses queer theory to examine Clift's later work, focusing on Wild River (dir. Elia Kazan, 1960); it argues that in this film Clift's narrative role, performance, and star persona radically challenge normative masculinity and heterosexuality.

Why coercion is wrong when it’s wrong

2013-04-04T13:31:02Z

Abstract: It is usually thought that wrongful acts of threat-involving coercion are wrong because they involve a violation of the freedom or autonomy of the targets of those acts. I argue here that this cannot possibly be right, and that in fact the wrongness of wrongful coercion has nothing at all to do with the effect such actions have on their targets. This negative thesis is supported by pointing out that what we say about the ethics of threatening (and thus the ethics of coercion) constrains what we can say about the ethics of warning and offering. Importantly, our favoured explanation of the wrongness of certain kinds of threatening should not commit us to condemning as wrong parallel cases of warning and offering. My positive project is to show how this can be done. I defend the claim that wrongful coercion is nothing more than the issuing of a conditional threat to do wrong, and that an agent's issuing of a conditional threat to do wrong is wrong because it constitutes motivation for that agent to adopt the announced intention to do wrong. The idea of explaining the wrongness of wrongful coercion in this way has gone unnoticed because we have thus far been mistaken about what a threat is. In this essay I present my moral analysis of coercion only after presenting a careful descriptive analysis of threats. On my view, it is essential to a threat that the announced intention is one that the agent does not possess before announcing it. This analysis makes it possible to elucidate the descriptive differences between threats, warnings and offers, which sets up the later project of elucidating the moral differences between them.

Differential timing of gene expression regulation between leptocephali of the two Anguilla eel species in the Sargasso Sea

2013-04-03T09:31:04Z

Abstract: The unique life-history characteristics of North Atlantic catadromous eels have long intrigued evolutionary biologists, especially with respect to mechanisms that could explain their persistence as two ecologically very similar but reproductively and geographically distinct species. Differential developmental schedules during young larval stages have commonly been hypothesized to represent such a key mechanism. We performed a comparative analysis of gene expression by means of microarray experiments with American and European eel leptocephali collected in the Sargasso Sea in order to test the alternative hypotheses of (1) differential timing of gene expression regulation during early development versus (2) species-specific differences in expression of particular genes. Our results provide much stronger support for the former hypothesis since no gene showed consistent significant differences in expression levels between the two species. In contrast, 146 genes showed differential timings of expression between species, although the observed expression level differences between the species were generally small. Consequently, species-specific gene expression regulation seems to play a minor role in species differentiation. Overall, these results show that the basis of the early developmental divergence between the American and European eel is probably influenced by differences in the timing of gene expression regulation for genes involved in a large array of biological functions.

Lateral entorhinal cortex is critical for novel object-context recognition

2013-06-09T01:02:09Z

Abstract: Episodic memory incorporates information about specific events or occasions including spatial locations and the contextual features of the environment in which the event took place. It has been modeled in rats using spontaneous exploration of novel configurations of objects, their locations, and the contexts in which they are presented. While we have a detailed understanding of how spatial location is processed in the brain relatively little is known about where the nonspatial contextual components of episodic memory are processed. Initial experiments measured c-fos expression during an object-context recognition (OCR) task to examine which networks within the brain process contextual features of an event. Increased c-fos expression was found in the lateral entorhinal cortex (LEC; a major hippocampal afferent) during OCR relative to control conditions. In a subsequent experiment it was demonstrated that rats with lesions of LEC were unable to recognize object-context associations yet showed normal object recognition and normal context recognition. These data suggest that contextual features of the environment are integrated with object identity in LEC and demonstrate that recognition of such object-context associations requires the LEC. This is consistent with the suggestion that contextual features of an event are processed in LEC and that this information is combined with spatial information from medial entorhinal cortex to form episodic memory in the hippocampus. © 2013 Wiley Periodicals, Inc.

Stochastic choice and consideration sets

2013-04-03T09:01:05Z

Abstract: We model a boundedly rational agent who su¤ers from limited attention. The agent considers each feasible alternative with a given (unobservable) probability, the attention parameter, and then chooses the alternative that maximises a prefer- ence relation within the set of considered alternatives. We show that this random choice rule is the only one for which the impact of removing an alternative on the choice probability of any other alternative is asymmetric and menu independent. Both the preference relation and the attention parameters are identi…ed uniquely by stochastic choice data.

Competing conservation objectives for predators and prey : estimating killer whale prey requirements for Chinook salmon

2013-05-12T04:08:58Z

Abstract: Ecosystem-based management (EBM) of marine resources attempts to conserve interacting species. In contrast to single-species fisheries management, EBM aims to identify and resolve conflicting objectives for different species. Such a conflict may be emerging in the northeastern Pacific for southern resident killer whales (Orcinus orca) and their primary prey, Chinook salmon (Oncorhynchus tshawytscha). Both species have at-risk conservation status and transboundary (Canada–US) ranges. We modeled individual killer whale prey requirements from feeding and growth records of captive killer whales and morphometric data from historic live-capture fishery and whaling records worldwide. The models, combined with caloric value of salmon, and demographic and diet data for wild killer whales, allow us to predict salmon quantities needed to maintain and recover this killer whale population, which numbered 87 individuals in 2009. Our analyses provide new information on cost of lactation and new parameter estimates for other killer whale populations globally. Prey requirements of southern resident killer whales are difficult to reconcile with fisheries and conservation objectives for Chinook salmon, because the number of fish required is large relative to annual returns and fishery catches. For instance, a U.S. recovery goal (2.3% annual population growth of killer whales over 28 years) implies a 75% increase in energetic requirements. Reducing salmon fisheries may serve as a temporary mitigation measure to allow time for management actions to improve salmon productivity to take effect. As ecosystem-based fishery management becomes more prevalent, trade-offs between conservation objectives for predators and prey will become increasingly necessary. Our approach offers scenarios to compare relative influence of various sources of uncertainty on the resulting consumption estimates to prioritise future research efforts, and a general approach for assessing the extent of conflict between conservation objectives for threatened or protected wildlife where the interaction between affected species can be quantified.

Estimating seasonal abundance of a central place forager using counts and telemetry data

2013-05-12T01:32:43Z

Abstract: Obtaining population estimates of species that are not easily observed directly can be problematic. However, central place foragers can often be observed some of the time, e.g. when seals are hauled out. In these instances, population estimates can be derived from counts, combined with information on the proportion of time that animals can be observed. We present a modelling framework to estimate seasonal absolute abundance using counts and information from satellite telemetry data. The method was tested on a harbour seal population in an area of southeast Scotland. Counts were made monthly, between November 2001 and June 2003, when seals were hauled out on land and were corrected for the proportion of time the seals were at sea using satellite telemetry. Harbour seals (n=25) were tagged with satellite relay data loggers between November 2001 and March 2003. To estimate the proportion of time spent hauled out, time at sea on foraging trips was modelled separately from haul-out behaviour close to haul-out sites because of the different factors affecting these processes. A generalised linear mixed model framework was developed to capture the longitudinal nature of the data and the repeated measures across individuals. Despite seasonal variability in the number of seals counted at haul-out sites, the model generated estimates of abundance, with an overall mean of 846 (95% CI: 767 to 979). The methodology shows the value of using count and telemetry data collected concurrently for estimating absolute abundance, information that is essential to assess interactions between predators, fish stocks and fisheries. Description: R.J.S. was supported by a Natural Environment Research Council studentship.

Photo-grammetric measurements of swimming speed and body length of basking sharks observed around the Hebrides, Scotland

2013-05-12T04:33:52Z

Abstract: Photo-grammetric techniques developed for measuring body length and small scale movement patterns of cetaceans were applied to surface swimming basking sharks off the west coast of Scotland. These methods removed the need for close approaches, reducing the likelihood of disturbing the focal animal. Average swimming speed was calculated from the total path length between shark locations measured at approximately one minute intervals. These average speeds varied from 0.49 to 0.73 ms−1 for tracks of between 30 and 170 minutes' duration. Body length measurements ranged between 2.35 and 6.43 m. For ten sharks where body length and swimming speed were measured there was a significant correlation between body length (L) and swimming speed (V) expressed as V = 0.36L033.

Synthesis of phosphonate and phostone analogues of ribose-1-phosphates

2013-05-12T04:10:23Z

Abstract: The synthesis of phosphonate analogues of ribose-1-phosphate and 5-fluoro-5-deoxyribose-1-phosphate is described. Preparations of both the alpha- and beta-phosphonate anomers are reported for the ribose and 5-fluoro-5-deoxyribose series and a synthesis of the corresponding cyclic phostones of each alpha-ribose is also reported. These compounds have been prepared as tools to probe the details of fluorometabolism in S. cattleya.

Three step synthesis of single diastereoisomers of the vicinal trifluoro motif

2013-05-12T04:10:18Z

Abstract: A three step route to single diastereoisomers of the vicinal trifluoromethyl motif is described. The route starts from either syn- or anti-alpha,beta-epoxy alcohols and takes a direct approach in that each of the three steps introduces a fluorine atom in a regio- and stereospecific manner. Starting from either the syn- or the anti-alpha,beta-epoxy alcohol, stereospecific reactions generate two separate diastereoisomeric series of this motif. The route is a significant improvement on an earlier six step strategy.

Passively mode locked femtosecond Tm:Sc2O3 laser at 2.1 mu m

2013-05-12T04:36:25Z

Abstract: We report on the passive mode locking of a Tm3+:Sc2O3 laser at 2.1 mu m using a semiconductor saturable absorber mirror based on InGaAsSb quantum wells. Transform-limited 218 fs pulses are generated with an average power of 210 mW. A maximum output power of 325 mW is produced during mode locking with the corresponding pulse duration of 246 fs at a pulse repetition frequency of 124.3 MHz. A Ti:sapphire laser is used as the pump source operating at 796 nm. (C) 2012 Optical Society of America Description: This work was supported by EPSRC

Algorithm-based continuous pulse duration tuning and performance control of a mode-locked laser diode

2013-05-12T04:36:24Z

Abstract: A control algorithm is presented that addresses the stability issues inherent to the operation of monolithic mode-locked laser diodes. It enables a continuous pulse duration tuning without any onset of Q-switching instabilities. A demonstration of the algorithm performance is presented for two radically different laser diode geometries and continuous pulse duration tuning between 0.5 ps to 2.2 ps and 1.2 ps to 10.2 ps is achieved. With practical applications in mind, this algorithm also facilitates control over performance parameters such as output power and wavelength during pulse duration tuning. The developed algorithm enables the user to harness the operational flexibility from such a laser with 'push-button' simplicity. (C) 2012 Optical Society of America

Crenarchaeal chromatin proteins Cren7 and Sul7 compact DNA by inducing rigid bends

2013-03-27T16:01:02Z

Abstract: Archaeal chromatin proteins share molecular and functional similarities with both bacterial and eukaryotic chromatin proteins. These proteins play an important role in functionally organizing the genomic DNA into a compact nucleoid. Cren7 and Sul7 are two crenarchaeal nucleoid-associated proteins, which are structurally homologous, but not conserved at the sequence level. Co-crystal structures have shown that these two proteins induce a sharp bend on binding to DNA. In this study, we have investigated the architectural properties of these proteins using atomic force microscopy, molecular dynamics simulations and magnetic tweezers. We demonstrate that Cren7 and Sul7 both compact DNA molecules to a similar extent. Using a theoretical model, we quantify the number of individual proteins bound to the DNA as a function of protein concentration and show that forces up to 3.5 pN do not affect this binding. Moreover, we investigate the flexibility of the bending angle induced by Cren7 and Sul7 and show that the protein-DNA complexes differ in flexibility from analogous bacterial and eukaryotic DNA-bending proteins.

hSSB1 interacts directly with the MRN complex stimulating its recruitment to DNA double-strand breaks and its endo-nuclease activity

2013-06-16T00:33:52Z

Abstract: hSSB1 is a recently discovered single-stranded DNA binding protein that is essential for efficient repair of DNA double-strand breaks (DSBs) by the homologous recombination pathway. hSSB1 is required for the efficient recruitment of the MRN complex to sites of DSBs and for the efficient initiation of ATM dependent signalling. Here we explore the interplay between hSSB1 and MRN. We demonstrate that hSSB1 binds directly to NBS1, a component of the MRN complex, in a DNA damage independent manner. Consistent with the direct interaction, we observe that hSSB1 greatly stimulates the endo-nuclease activity of the MRN complex, a process that requires the C-terminal tail of hSSB1. Interestingly, analysis of two point mutations in NBS1, associated with Nijmegen breakage syndrome, revealed weaker binding to hSSB1, suggesting a possible disease mechanism.

hSSB1 rapidly binds at the sites of DNA double-strand breaks and is required for the efficient recruitment of the MRN complex

2013-06-16T00:33:48Z

Abstract: hSSB1 is a newly discovered single-stranded DNA (ssDNA)-binding protein that is essential for efficient DNA double-strand break signalling through ATM. However, the mechanism by which hSSB1 functions to allow efficient signalling is unknown. Here, we show that hSSB1 is recruited rapidly to sites of double-strand DNA breaks (DSBs) in all interphase cells (G1, S and G2) independently of, CtIP, MDC1 and the MRN complex (Rad50, Mre11, NBS1). However expansion of hSSB1 from the DSB site requires the function of MRN. Strikingly, silencing of hSSB1 prevents foci formation as well as recruitment of MRN to sites of DSBs and leads to a subsequent defect in resection of DSBs as evident by defective RPA and ssDNA generation. Our data suggests that hSSB1 functions upstream of MRN to promote its recruitment at DSBs and is required for efficient resection of DSBs. These findings, together with previous work establish essential roles of hSSB1 in controlling ATM activation and activity, and subsequent DSB resection and homologous recombination (HR).

Crystallization of Ranasmurfin, a blue coloured protein from Polypedates leucomystax

2013-05-12T02:01:33Z

Abstract: Ranasmurfin, a previously uncharacterized similar to 13 kDa blue protein found in the nests of the frog Polypedates leucomystax, has been purified and crystallized. The crystals are an intense blue colour and diffract to 1.51 angstrom with P2(1) symmetry and unit-cell parameters a = 40.9, b = 59.9, c = 45.0 angstrom, beta = 93.3 degrees. Self-rotation function analysis indicates the presence of a dimer in the asymmetric unit. Biochemical data suggest that the blue colour of the protein is related to dimer formation. Sequence data for the protein are incomplete, but thus far have identified no model for molecular replacement. A fluorescence scan shows a peak at 9.676 keV, indicating that the protein binds zinc and suggesting a route for structure solution.

Extortion and the ethics of "topping up"

2013-03-26T16:31:02Z

Consequentialism's double-edged aword

2013-03-26T16:31:01Z

Abstract: Recent work on consequentialism has revealed it to be more flexible than previously thought. Consequentialists have shown how their theory can accommodate certain features with which it has long been considered incompatible, such as agent-centered constraints. This flexibility is usually thought to work in consequentialism's favor. I want to cast doubt on this assumption. I begin by putting forward the strongest statement of consequentialism's flexibility: the claim that, whatever set of intuitions the best non-consequentialist theory accommodates, we can construct a consequentialist theory that can do the same while still retaining whatever is compelling about consequentialism. I argue that if this is true then most likely the non-consequentialist theory with which we started will turn out to have that same compelling feature. So while this extreme flexibility, if indeed consequentialism has it (a question I leave to the side), makes consequentialism more appealing, it makes non-consequentialism more appealing too.

Facial skin coloration affects perceived health of human faces

2013-05-12T04:02:30Z

Abstract: Numerous researchers have examined the effects of skin condition, including texture and color, on the perception of health, age, and attractiveness in human faces. They have focused on facial color distribution, homogeneity of pigmentation, or skin quality. We here investigate the role of overall skin color in determining perceptions of health from faces by allowing participants to manipulate the skin portions of color-calibrated Caucasian face photographs along CIELab color axes. To enhance healthy appearance, participants increased skin redness (a*), providing additional support for previous findings that skin blood color enhances the healthy appearance of faces. Participants also increased skin yellowness (b*) and lightness (L*), suggesting a role for high carotenoid and low melanin coloration in the healthy appearance of faces. The color preferences described here resemble the red and yellow color cues to health displayed by many species of nonhuman animals. Description: I stephen was funded by a BBSRC Studentship. M Stirrat was funded by an EPSRC Studentship.

Skin blood perfusion and oxygenation colour affect affect perceived human health

2013-03-26T16:01:04Z

Abstract: Skin blood perfusion and oxygenation depends upon cardiovascular, hormonal and circulatory health in humans and provides socio-sexual signals of underlying physiology, dominance and reproductive status in some primates. We allowed participants to manipulate colour calibrated facial photographs along empirically-measured oxygenated and deoxygenated blood colour axes both separately and simultaneously, to optimise healthy appearance. Participants increased skin blood colour, particularly oxygenated, above basal levels to optimise healthy appearance. We show, therefore, that skin blood perfusion and oxygenation influence perceived health in a way that may be important to mate choice. Description: I Stephen was funded by a BBSRC Studentship.

Trust, distrust and commitment

2013-05-12T04:34:00Z

Runaway sexual selection without genetic correlations : social environments and flexible mate choice initiate and enhance the Fisher process

2013-06-09T01:02:01Z

Abstract: Female mating preferences are often flexible, reflecting the social environment in which they are expressed. Associated indirect genetic effects (IGEs) can affect the rate and direction of evolutionary change, but sexual selection models do not capture these dynamics. We incorporate IGEs into quantitative genetic models to explore how variation in social environments and mate choice flexibility influence Fisherian sexual selection. The importance of IGEs is that runaway sexual selection can occur in the absence of a genetic correlation between male traits and female preferences. Social influences can facilitate the initiation of the runaway process and increase the rate of trait elaboration. Incorporating costs to choice do not alter the main findings. Our model provides testable predictions: (1) genetic covariances between male traits and female preferences may not exist, (2) social flexibility in female choice will be common in populations experiencing strong sexual selection, (3) variation in social environments should be associated with rapid sexual trait divergence, and (4) secondary sexual traits will be more elaborate than previously predicted. Allowing feedback from the social environment resolves discrepancies between theoretical predictions and empirical data, such as why indirect selection on female preferences, theoretically weak, might be sufficient for preferences to become elaborated.

You are what you eat : Within-subject increases in fruit and vegetable consumption confer beneficial skin-color changes

2013-06-02T04:01:00Z

Abstract: Background: Fruit and vegetable consumption and ingestion of carotenoids have been found to be associated with human skin-color (yellowness) in a recent cross-sectional study. This carotenoid-based coloration contributes beneficially to the appearance of health in humans and is held to be a sexually selected cue of condition in other species. Methodology and Principal Findings: Here we investigate the effects of fruit and vegetable consumption on skin-color longitudinally to determine the magnitude and duration of diet change required to change skin-color perceptibly. Diet and skin-color were recorded at baseline and after three and six weeks, in a group of 35 individuals who were without makeup, self-tanning agents and/or recent intensive UV exposure. Six-week changes in fruit and vegetable consumption were significantly correlated with changes in skin redness and yellowness over this period, and diet-linked skin reflectance changes were significantly associated with the spectral absorption of carotenoids and not melanin. We also used psychophysical methods to investigate the minimum color change required to confer perceptibly healthier and more attractive skin-coloration. Modest dietary changes are required to enhance apparent health (2.91 portions per day) and attractiveness (3.30 portions). Conclusions: Increased fruit and vegetable consumption confers measurable and perceptibly beneficial effects on Caucasian skin appearance within six weeks. This effect could potentially be used as a motivational tool in dietary intervention. Description: R Whitehead was funded by an ESRC Studentship.

Single-molecule chemical denaturation of riboswitches

2013-04-18T11:31:04Z

Abstract: To date, single-molecule RNA science has been developed almost exclusively around the effect of metal ions as folding promoters and stabilizers of the RNA structure. Here, we introduce a novel strategy that combines single-molecule Förster resonance energy transfer (FRET) and chemical denaturation to observe and manipulate RNA dynamics. We demonstrate that the competing interplay between metal ions and denaturant agents provides a platform to extract information that otherwise will remain hidden with current methods. Using the adenine-sensing riboswitch aptamer as a model, we provide strong evidence for a rate-limiting folding step of the aptamer domain being modulated through ligand binding, a feature that is important for regulation of the controlled gene. In the absence of ligand, the rate-determining step is dominated by the formation of long-range key tertiary contacts between peripheral stem-loop elements. In contrast, when the adenine ligand interacts with partially folded messenger RNAs, the aptamer requires specifically bound Mg2+ ions, as those observed in the crystal structure, to progress further towards the native form. Moreover, despite that the ligand-free and ligand-bound states are indistinguishable by FRET, their different stability against urea-induced denaturation allowed us to discriminate them, even when they coexist within a single FRET trajectory; a feature not accessible by existing methods.

Remarkable transition from rocksalt/perovskite layered structure to fluorite/rocksalt layered structure in rapidly cooled Ln2CuO4

2013-05-13T12:31:04Z

Abstract: Lanthanide cuprates of formula Ln2CuO4 exist in two principal forms, T and T′ which are renowned for their exhibition at low temperatures of hole and electronic types of superconductivity, respectively. These structures differ primarily in the arrangement of oxygen between the perovskite layers and also in nature of the copper oxygen planes. The Cu-O distance in the T structure (~1.90 Å) is much shorter than the T′ (1.97Å), reflecting a transition between partial Cu+ and partial Cu3+ character. In seeking to find compositions that bridge these two structure/electron carrier types, we observed the transition from a T structure to a T′ type structure, resulting in the metastable form T″ with slightly larger volume but similar character to T′. This transition from T to T″ is associated with 5% increase in a and a 5% decrease in c parameters of the tetragonal unit cells, which results in disintegration of ceramic bodies. Description: This work was supported by EPSRC

Synthesis of ammonia directly from air and water at ambient temperature and pressure

2013-03-26T14:01:01Z

Abstract: The N equivalent to Nbond (225 kcal mol(-1)) in dinitrogen is one of the strongest bonds in chemistry therefore artificial synthesis of ammonia under mild conditions is a significant challenge. Based on current knowledge, only bacteria and some plants can synthesise ammonia from air and water at ambient temperature and pressure. Here, for the first time, we report artificial ammonia synthesis bypassing N-2 separation and H-2 production stages. A maximum ammonia production rate of 1.14 x 10(-5) mol m(-2) s(-1) has been achieved when a voltage of 1.6 V was applied. Potentially this can provide an alternative route for the mass production of the basic chemical ammonia under mild conditions. Considering climate change and the depletion of fossil fuels used for synthesis of ammonia by conventional methods, this is a renewable and sustainable chemical synthesis process for future.

Weak Te,Te interactions through the looking glass of NMR spin-spin coupling

2013-05-12T04:36:59Z

Abstract: Across the bay: J(125Te,125Te) spin–spin coupling is a highly sensitive probe into the electronic and geometric structure of 1,8-peri-substituted naphthalene tellurium derivatives. The coupling is related to the onset of multicenter bonding in these systems.

Isolable phosphanylidene phosphorane with a sterically accessible two-coordinate phosphorus atom

2013-06-02T04:31:25Z

Simultaneous control of regioselectivity and enantioselectivity in the hydroxycarbonylation and methoxycarbonylation of vinyl arenes

2013-03-26T12:01:03Z

Abstract: Using a family of novel mononuclear and dinuclear palladium complexes of phanephos ligands, the simultaneous control of regioselectivity and enantioselectivity in the hydroxycarbonylation and alkoxycarbonylation of styrene derivatives has been realised for the first time.

Iso-seco-tanapartholides : isolation, synthesis and biological evaluation

2013-06-16T04:31:24Z

Abstract: The isolation, identification and total synthesis of two plant-derived inhibitors of the NF-kappa B signaling pathway from the iso-seco-tanapartholide family of natural products is described. A key step in the efficient reaction sequence is a late-stage oxidative cleavage reaction that was carried out in the absence of protecting groups to give the natural products directly. A detailed comparison of the synthetic material with samples of the natural products proved informative. Biological studies on synthetic material confirmed that these compounds act late in the NF-kappa B signaling pathway. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)

The timing of asset trade and optimal policy in dynamic open economies

2013-03-22T14:01:02Z

Abstract: Using a standard open economy DSGE model, it is shown that the timing of asset trade relative to policy decisions has a potentially important impact on the welfare evaluation of monetary policy at the individual country level. If asset trade in the initial period takes place before the announcement of policy, a national policymaker can choose a policy rule which reduces the work effort of households in the policymaker’s country in the knowledge that consumption is fully insured by optimally chosen international portfolio positions. But if asset trade takes place after the policy announcement, this insurance is absent and households in the policymaker’s country bear the full consumption consequences of the chosen policy rule. The welfare incentives faced by national policymakers are very different between the two cases. Numerical examples confirm that asset market timing has a significant impact on the optimal policy rule.

Identification through technical analysis : A study of charting and UK non-professional investors

2013-05-12T03:37:11Z

Abstract: The usefulness of technical analysis, or charting, has been questioned because it flies in the face of the 'random walk' and tests present conflicting results. We examine chartists' decision-making techniques and derive a taxonomy of charting strategies based on investors' market ontologies and calculative strategies. This distinguishes between trend-seekers and pattern-seekers, and trading as a system or an art. We argue that interpretative activity plays a more important role than previously thought and suggest that charting's main appeal for users lies in its power as a heuristic device regardless of its effectiveness at generating returns.

Morality, adapted

2013-03-21T17:01:02Z

Abstract: Over the last few decades, scientists have been busy debunking the myth that nonhuman animals relate to each other in a primarily competitive, aggressive way. What they have found is that many species of animal, including many of those most closely related to humans, display a remarkable range of cooperative, "prosocial" behavior. In fact, it appears that some animal societies adhere to a moral code. What is preventing us, then, from saying that the members of these societies are moral beings? Nothing important, according to a recent book. Probing further into this question, I suggest that in fact quite a lot is at risk in making this move. To integrate nonhuman animals fully into the moral domain, we may have to adapt our conception of morality in some very troublesome ways.

The opportunity costs of aid

2013-03-20T21:31:01Z

Description: Responce to Helena Watson, Aid, aid everywhere but still not a drop in the sink. BMJ 2009; 338: a3136

Will prescriptions for cultural change improve the NHS?

2013-03-20T16:01:03Z

Abstract: The recent Francis report diagnoses serious cultural deficiencies in the NHS and recommends fundamental cultural change. Huw Davies and Russell Mannion examine what research tells us about the likelihood of success.

Transnational families and the family nexus : perspectives of Indonesian and Filipino children left behind by migrant parent(s)

2013-06-04T11:01:00Z

Abstract: As a significant supplier of labour migrants, Southeast Asia presents itself as an important site for the study of children in transnational families who are growing up separated from at least one migrant parent and sometimes cared for by ‘other mothers’. Through the often-neglected voices of left-behind children, this paper investigates the impact of parental migration and the resulting reconfiguration of care arrangements on the subjective well-being of migrants’ children in two Southeast Asian countries, Indonesia and the Philippines. We theorise the child’s position in the transnational family nexus through the framework of the ‘care triangle’, representing interactions between three subject groups – ‘left-behind’ children, non-migrant parents/other carers, and migrant parent/s. Using both quantitative (from 1,010 households) and qualitative (from 32 children) data from a study of Child Health and Migrant Parents in South-East Asia (CHAMPSEA), we examine relationships within the caring spaces of both home and transnational spaces. The interrogation of different dimensions of care reveals the importance of contact with parents (both migrant and non-migrant) to subjective child well-being, and the diversity of experiences and intimacies among children in the two study countries.

On global regularity of 2D generalized magnetohydrodynamic equations

2013-05-21T09:01:01Z

Abstract: In this article we study the global regularity of 2D generalized magnetohydrodynamic equations (2D GMHD), in which the dissipation terms are $- \nu \left( - \triangle \right)^{\alpha} u$ and $- \kappa \left( - \triangle \right)^{\beta} b$. We show that smooth solutions are global in the following three cases: $\alpha \geqslant 1 / 2, \beta \geqslant 1$; $0 \leqslant \alpha < 1 / 2, 2 \alpha + \beta > 2$; $\alpha \geqslant 2, \beta = 0$. We also show that in the inviscid case $\nu = 0$, if $\beta > 1$, then smooth solutions are global as long as the direction of the magnetic field remains smooth enough.

The unbearable emptiness of entrepreneurship

2013-03-16T14:01:02Z

Abstract: Review of 'Unmasking the Entrepreneur' by Campbell Jones and Andre Spicer, Edward Elgar, 2009

Sharp global nonlinear stability for a fluid overlying a highly porous material

2013-05-12T03:05:05Z

Abstract: The stability of convection in a two-layer system in which a layer of fluid with a temperature-dependent viscosity overlies and saturates a highly porous material is studied. Owing to the difficulties associated with incorporating the nonlinear advection term in the Navier-Stokes equations into a stability analysis, previous literature on fluid/porous thermal convection has modelled the fluid using the linear Stokes equations. This paper derives global stability for the full nonlinear system, by utilizing a model proposed by Ladyzhenskaya. The nonlinear stability boundaries are shown to be sharp when compared with the linear instability thresholds.

Nonlinear stability of the one-domain approach to modelling convection in superposed fluid and porous layers

2013-05-12T02:32:50Z

Abstract: Studies of the nonlinear stability of fluid/porous systems have been developed very recently. A two-domain modelling approach has been adopted in previous works, but was restricted to specific configurations. The extension to the more general case of a Navier–Stokes modelled fluid over a porous material was not achieved for the two-domain approach owing to the difficulties associated with handling the interfacial boundary conditions. This paper addresses this issue by adopting a one-domain approach, where the governing equations for both regions are combined into a unique set of equations that are valid for the entire domain. It is shown that the nonlinear stability bound, in the one-domain approach, is very sharp and hence excludes the possibility of subcritical instabilities. Moreover, the one-domain approach is compared with an equivalent two-domain approach, and excellent agreement is found between the two.

Instability in internal solitary waves with trapped cores

2013-05-12T04:12:21Z

Abstract: A numerical method that employs a combination of contour advection and pseudo-spectral techniques is used to investigate instability in internal solitary waves with trapped cores. A three-layer configuration for the background stratification in which the top two layers are linearly stratified and the lower layer is homogeneous is considered throughout. The strength of the stratification in the very top layer is chosen to be sufficient so that waves of depression with trapped cores can be generated. The flow is assumed to satisfy the Dubriel-Jacotin-Long equation both inside and outside of the core region. The Brunt-Vaisala frequency is modelled such that it varies from a constant value outside of the core to zero inside the core over a sharp but continuous transition length. This results in a stagnant core in which the vorticity is zero and the density is homogeneous and approximately equal to that at the core boundary. The time dependent simulations show that instability occurs on the boundary of the core. The instability takes the form of Kelvin-Helmholtz billows. If the instability in the vorticity field is energetic enough, disturbance in the buoyancy field is also seen and fluid exchange takes place across the core boundary. Occurrence of the Kelvin-Helmholtz billows is attributed to the sharp change in the vorticity field at the boundary between the core and the pycnocline. The numerical scheme is not limited by small Richardson number unlike the other alternatives currently available in the literature which appear to be.

Shear induced breaking of large amplitude internal solitary waves

2013-05-12T01:33:26Z

Convectively induced shear instability in large amplitude internal solitary waves

2013-05-12T01:33:25Z

Abstract: Laboratory study has been carried out to investigate the instability of an internal solitary wave of depression in a shallow stratified fluid system. The experimental campaign has been supported by theoretical computations and has focused on a two layered stratification consisting of a homogeneous dense layer below a linearly stratified top layer. The initial background stratification has been varied and it is found that the onset and intensity of breaking are affected dramatically by changes in the background stratification. Manifestations of a combination of shear and convective instability are seen on the leading face of the wave. It is shown that there is an interplay between the two instability types and convective instability induces shear by enhancing isopycnal compression. Variation in the upper boundary condition is also found to have an effect on stability. In particular, the implications for convective instability are shown to be profound and a dramatic increase in wave amplitude is seen for a fixed (as opposed to free) upper boundary condition.

To ping or not to ping : the use of active acoustic devices in mitigating interactions between small cetaceans and gillnet fisheries

2013-03-15T12:01:02Z

Abstract: Active sound emitters (‘pingers’) are used in several gillnet fisheries to reduce bycatch of small cetaceans, and/or to reduce depredation by dolphins. Here, we review studies conducted to determine how effective these devices may be as management tools. Significant reductions in bycatch of harbour porpoise Phocoena phocoena, franciscana Pontoporia blainvillei, common Delphinus delphis and striped dolphin Stenella coeruleoalba, and beaked whales as a group have been demonstrated. For harbour porpoise this result has been replicated in 14 controlled experiments in North America and Europe, and appears to be due to porpoises avoiding the area ensonified by pingers. Two gillnet fisheries (California-Oregon driftnet fishery for swordfish; New England groundfish fishery) with mandatory pinger use have been studied for over a decade. Bycatch rates of dolphins/porpoises have fallen by 50 to 60%, and there is no evidence of bycatch increasing over time due to habituation. In both fisheries, bycatch rates were significantly higher in nets sparsely equipped with pingers or in which pingers had failed, than in nets without any pingers at all. Studies of pinger use to reduce depredation by bottlenose dolphins Tursiops truncatus generally show small and inconsistent improvements in fish catches and somewhat reduced net damage. Dolphin bycatch in these fisheries is rare, but still occurs in nets with pingers. Taken together, these studies suggest that the most promising candidates for bycatch reduction via pinger use will be gillnet fisheries in developed countries in which the bycaught cetaceans are generally neophobic species with large home ranges. We offer a set of lessons learned from the last decade of bycatch management.

Embodied metaphors and emotions in the moralization of restrained eating practices

2013-03-15T10:31:02Z

Abstract: Moralization is the process whereby preferences are converted to values (Rozin, 1999). Two studies used an embodied metaphor approach, in which moral metaphors are grounded in one’s sense of physical cleanliness, to investigate whether restrained eating practices are moralized among women. Specifically, we predicted that the regulation of food intake by women is embodied in their feelings of physical cleanliness. Study 1 found that failures of restrained eating (i.e., overeating) increased accessibility of physical cleanliness-related words for women, but not men. Study 2 found that increased negative moral emotions fully mediated the effect of overeating on a desire for physical cleanliness. Overall, the studies argue for the importance of morality in restrained eating and in the central role of emotions in the embodiment of cognitive metaphors.

The Life-and-Death Journey of the Soul : Interpreting the Myth of Er

2013-03-14T12:34:11Z

Tissue-specific transcriptomics in the field cricket Teleogryllus oceanicus

2013-03-14T12:33:17Z

Abstract: Field crickets (family Gryllidae) frequently are used in studies of behavioral genetics, sexual selection, and sexual conflict, but there have been no studies of transcriptomic differences among different tissue types. We evaluated transcriptome variation among testis, accessory gland, and the remaining whole-body preparations from males of the field cricket, Teleogryllus oceanicus. Non-normalized cDNA libraries from each tissue were sequenced on the Roche 454 platform, and a master assembly was constructed using testis, accessory gland, and whole-body preparations. A total of 940,200 reads were assembled into 41,962 contigs, to which 36,856 singletons (reads not assembled into a contig) were added to provide a total of 78,818 sequences used in annotation analysis. A total of 59,072 sequences (75%) were unique to one of the three tissues. Testis tissue had the greatest proportion of tissue-specific sequences (62.6%), followed by general body (56.43%) and accessory gland tissue (44.16%). We tested the hypothesis that tissues expressing gene products expected to evolve rapidly as a result of sexual selection—testis and accessory gland—would yield a smaller proportion of BLASTx matches to homologous genes in the model organism Drosophila melanogaster compared with whole-body tissue. Uniquely expressed sequences in both testis and accessory gland showed a significantly lower rate of matching to annotated D. melanogaster genes compared with those from general body tissue. These results correspond with empirical evidence that genes expressed in testis and accessory gland tissue are rapidly evolving targets of selection. Description: This work was supported by a Natural Environment Research Council Junior Postdoctoral Fellowship (NE/G014906/1) and Pacific Rim Foundation funding (08-T-PRRP-05-0029) to N.W.B.

Migration or immigration? : Ireland’s new and unexpected Polish-language community

2013-03-11T12:31:02Z

Amousia : living without the Muses

2013-03-08T09:01:05Z

Generating transformation semigroups using endomorphisms of preorders, graphs, and tolerances

2013-05-12T03:34:25Z

Abstract: Let ΩΩ be the semigroup of all mappings of a countably infinite set Ω. If U and V are subsemigroups of ΩΩ, then we write U≈V if there exists a finite subset F of ΩΩ such that the subsemigroup generated by U and F equals that generated by V and F. The relative rank of U in ΩΩ is the least cardinality of a subset A of ΩΩ such that the union of U and A generates ΩΩ. In this paper we study the notions of relative rank and the equivalence ≈ for semigroups of endomorphisms of binary relations on Ω. The semigroups of endomorphisms of preorders, bipartite graphs, and tolerances on Ω are shown to lie in two equivalence classes under ≈. Moreover such semigroups have relative rank 0, 1, 2, or d in ΩΩ where d is the minimum cardinality of a dominating family for NN. We give examples of preorders, bipartite graphs, and tolerances on Ω where the relative ranks of their endomorphism semigroups in ΩΩ are 0, 1, 2, and d. We show that the endomorphism semigroups of graphs, in general, fall into at least four classes under ≈ and that there exist graphs where the relative rank of the endomorphism semigroup is 2ℵ0.

Workforce development and challenging behaviour : training staff to treat, to manage or to cope?

2013-06-02T00:31:24Z

Abstract: Staff working directly with adults challenging behaviours in learning disability services need to be very good at what they do. They also need to want to do the job. A theory-practice gap exists, however, between what is known about effective, evidence-based approaches and whether and how these are used in person-centred, community services. Many front line staff working with people with the most serious challenging behaviours do not have the skills to implement programmes to change behaviour. This discussion paper reviews workforce development in the context of clinical and service guidelines and asks whether the legitimate purview of frontline staff is a balance of treating challenging behaviour, managing it or to simply coping with it on a daily basis, whilst maintaining the best quality of life possible for service users.

Safeguarding adults at risk of harm in Scotland : legislation, policy and practice

2013-03-07T17:01:06Z

Description: Special Issue: Safeguarding adults at risk of harm in Scotland.

Reducing health inequalities in Scotland : the involvement of people with learning disabilities as national health service reviewers

2013-05-12T02:31:31Z

Abstract: Reducing health inequalities is a key priority for the Scottish Government. Health authorities are expected to meet quality targets. The involvement of people with learning disabilities in health service review teams has been one of the initiatives used in by NHS Quality Improvement Scotland to empower patients and improve health services. This paper describes this initiative, how it was planned, and an evaluation by health staff, carers and people with learning disabilities. Recommendations are made to ensure the future success of this type of initiative in Scotland and elsewhere. This initiative was evaluated positively and tested traditional assumptions, challenging the power imbalance in patient-provider relationships. The theory and the practice of including people with learning disabilities as “expert patient” reviewers are discussed.

Assessment of interpersonal risk (AIR) in adults with learning disabilities and challenging behaviour – piloting a new risk assessment tool

2013-05-12T04:11:45Z

Abstract: A new risk assessment tool, Assessment of Interpersonal Risk (AIR), was piloted and evaluated to measure risk factors and compatibility between individuals living in an assessment and treatment unit in one NHS area. The adults with learning disabilities in this unit had severe and enduring mental health problems and/or behaviour that is severely challenging. The aims of this small-scale research project were to estimate the reciprocal risk to and from each individual across five main risk domains and to enhance professional judgement to make defensible decisions about interpersonal risk. Data were recorded on incidents involving five individuals over a period of 6 months. Individual Rating Profiles were incorporated into existing Individual Risk Management Plans, together with interpersonal profiles, recording risk evaluations between named individuals across the five risk domains. Results showed that the AIR tool may be a useful addition to existing effective risk management, to inform assessments and future discharge planning. Description: This article is a report on a research project funded by the Knowledge Transfer Partnership. This research was a joint project with NHS Fife. The accelerated long-stay Learning Disability Hospital closure programme in Scotland throughout the late 1990s and from 2000 onwards, resulted in the movement of residents both within and out-with these Hospitals to either community based housing models or to community based In-patient services. The legacy and impact of this residential service re-provision was that individuals experienced changes in those they lived with, and those who supported them. This process took place against the back-drop and dynamic of associated changes in environmental, procedural, situational and interpersonal risk. It was in recognition of the challenge that this change programme presented to care services in terms of defensible risk assessment and management that the Assessment of Interpersonal Risk tool was developed.

A pilot project : evaluating community nurses' knowledge and understanding of the Adult Support and Protection (Scotland) Act 2007

2013-05-12T04:07:19Z

Abstract: Purpose: To evaluate understanding and knowledge of the Adult Support and Protection (Scotland) Act 2007 in a sample of community nurses working in learning disability services in Scotland. Design: Ten community nurses who worked in learning disability services in one NHS area were tested at two time points, four months apart using a questionnaire designed for this study by researchers and practitioners. Level of previous national training in the Adult Support and Protection Act, and length of time working with people with learning disabilities were recorded. Three domains of adult protection were included in the questionnaire: Principles of the Act and definitions; Adults at Risk of Harm; Protection, Assessment, Removal and Banning Orders. Findings: Questionnaire scores varied widely overall and across the three domains. There was no correlation between individual scores and training or length of work experience. The level of knowledge was below what might have been expected for this group, given the level of training and experience. Carefully designed verification of the impact of nationally approved Adult Support and Protection training is needed. Originality/Value: There is an absence of research in evaluating the impact of the approved Scottish Government training materials on staff knowledge and understanding of the 2007 Act, with staff attendance being taken as the main measure of training compliance. This was a small scale, pilot study and recommendations are made for the scope and methods of evaluation. Description: This research was funded from a grant from Queens Nursing Institute Scotland. Special Issue: Safeguarding adults at risk of harm in Scotland. Guest editor(s): Martin Campbell, James Hogg and Bridget Penhale.

Number of degrees of freedom and energy spectrum of surface quasi-geostrophic turbulence

2013-05-12T04:14:15Z

Abstract: We study both theoretically and numerically surface quasi-geostrophic turbulence regularized by the usual molecular viscosity, with an emphasis on a number of classical predictions. It is found that the system's number of degrees of freedom N, which is defined in terms of local Lyapunov exponents, scales as Re-3/2, where R e is the Reynolds number expressible in terms of the viscosity, energy dissipation rate and system's integral scale. For general power-law energy spectra k(-alpha), a comparison of N with the number of dynamically active Fourier modes, i.e. the modes within the energy inertial range, yields alpha = 5/3. This comparison further renders the scaling Re-1/2 for the exponential dissipation rate at the dissipation wavenumber. These results have been predicted on the basis of Kolmogorov's theory. Our approach thus recovers these classical predictions and is an analytic alternative to the traditional phenomenological method. The implications of the present findings are discussed in conjunction with related results in the literature. Support for the analytic results is provided through a series of direct numerical simulations. Description: L.A.K.B. was supported by an EPSRC post-graduate studentship.

Mg structural state in coral aragonite and implications for the paleoenvironmental proxy

2013-05-12T02:35:46Z

Abstract: Thermodynamic calculations and inorganic precipitation experiments indicate a relationship between aragonite Mg/Ca and water temperature. This offers a route to reconstruct seawater temperatures from fossil corals. Fundamental to this is the assumption that Mg2+ exchanges for Ca2+ within carbonate. We present X-ray Absorption Fine Structure (XAFS) data to indicate the structural state of Mg in modern Porites coral skeletons. We show Mg is not in aragonite, but hosted by a disordered Mg-bearing material. Mg may be predominantly hosted in organic materials or as a highly disordered inorganic phase, e. g., a nanoparticulate form of Mg carbonate or hydroxide. Reported correlations between seawater temperature and coral Mg/Ca are unlikely to be consistent between corals and hence analysis of Mg/Ca in fossils is unlikely to produce accurate climate reconstructions. We anticipate XAFS will be applied widely to environmental proxies and become an important tool in identifying those that reconstruct accurate climates.

Staff training and challenging behaviour : Who needs it?

2013-05-12T01:34:43Z

Abstract: Staff working directly with people who have challenging behaviour in learning disability services need to be D good at what they do. These staff are trained by their employers to manage and to treat challenging behaviours and to improve the quality of life of people in their care. While such training is generally well evaluated by care staff, there is limited evidence that training alone changes poor attitudes or improves staff performance. Training has not been linked to quality of outcomes for service users. From research on treating challenging behaviour, achieving maintenance of behavioural gains after treatment has been discontinued is the exception rather than the rule. Can the same be said for maintaining gains achieved through staff training in the area of challenging behaviour? This discussion article reviews the value of training for staff working with people with challenging behaviour.

Dimer-dimer stacking interactions are important for nucleic acid binding by the archaeal chromatin protein Alba

2013-06-16T04:31:11Z

Abstract: Archaea use a variety of small basic proteins to package their DNA. One of the most widespread and highly conserved is the Alba (Sso10b) protein. Alba interacts with both DNA and RNA in vitro, and we show in the present study that it binds more tightly to dsDNA (double-stranded DNA) than to either ssDNA (single-stranded DNA) or RNA. The Alba protein is dimeric in solution, and forms distinct ordered complexes with DNA that have been visualized by electron microscopy studies; these studies suggest that, on binding dsDNA, the protein forms extended helical protein fibres. An end-to-end association of consecutive Alba dimers is suggested by the presence of a dimer-dimer interface in crystal structures of Alba from several species, and by the strong conservation of the interface residues, centred on Are and Phe(60). In the present study we map perturbation of the polypeptide backbone of Alba upon binding to DNA and RNA by NMR, and demonstrate the central role of Phe(60) in forming the dimer dimer interface. Site-directed spin labelling and pulsed ESR are used to confirm that an end-to-end, dimer dimer interaction forms in the presence of dsDNA.

Coronal heating by the partial relaxation of twisted loops

2013-03-05T09:31:06Z

Abstract: Context: Relaxation theory offers a straightforward method for estimating the energy that is released when a magnetic field becomes unstable, as a result of continual convective driving. Aims: We present new results obtained from nonlinear magnetohydrodynamic (MHD) simulations of idealised coronal loops. The purpose of this work is to determine whether or not the simulation results agree with Taylor relaxation, which will require a modified version of relaxation theory applicable to unbounded field configurations. Methods: A three-dimensional (3D) MHD Lagrangian-remap code is used to simulate the evolution of a line-tied cylindrical coronal loop model. This model comprises three concentric layers surrounded by a potential envelope; hence, being twisted locally, each loop configuration is distinguished by a piecewise-constant current profile. Initially, all configurations carry zero-net-current fields and are in ideally unstable equilibrium. The simulation results are compared with the predictions of helicity conserving relaxation theory. Results: For all simulations, the change in helicity is no more than 2% of the initial value; also, the numerical helicities match the analytically-determined values. Magnetic energy dissipation predominantly occurs via shock heating associated with magnetic reconnection in distributed current sheets. The energy release and final field profiles produced by the numerical simulations are in agreement with the predictions given by a new model of partial relaxation theory: the relaxed field is close to a linear force free state; however, the extent of the relaxation region is limited, while the loop undergoes some radial expansion. Conclusions: The results presented here support the use of partial relaxation theory, specifically, when calculating the heating-event distributions produced by ensembles of kink-unstable loops.

Seasonal inflow of warm water onto the southern Weddell Sea continental shelf, Antarctica

2013-05-12T04:14:28Z

Abstract: To capture the austral summer to winter transition in water mass properties over the southern Weddell Sea continental shelf and slope region Weddell seals were tagged with miniaturized conductivity–temperature–depth sensors in February 2011. During the following 8 months the instruments yielded about 9000 temperature–salinity profiles from a previously undersampled area. This allows, for the first time, a description of the seasonality of warm water intrusions onto the shelf. A temperature section across the Filchner Depression and eastern shelf shows a pronounced decrease in warm water inflow from summer to winter, further supported by an almost 3–year long time series from a shelf–break mooring. The seasonal variability is related to the surface wind stress and an associated deepening of the off–shore core of Warm Deep Water.

Los hombres-perro de Felisberto Hernández

2013-02-28T11:01:01Z

Fitting complex ecological point process models with integrated nested Laplace approximation

2013-02-26T13:01:04Z

Abstract: Summary 1. We highlight an emerging statistical method, integrated nested Laplace approximation (INLA), which is ideally suited for fitting complex models to many of the rich spatial data sets that ecologists wish to analyse. 2. INLA is an approximation method that nevertheless provides very exact estimates. In this article, we describe the INLA methodology highlighting where it offers opportunities for drawing inference from (spatial) ecological data that would previously have been too complex to make practical model fitting feasible. 3. We use INLA to fit a complex joint model to the spatial pattern formed by a plant species, Thymus carnosus, as well as to the health status of each individual. 4. The key ecological result revealed by our spatial analysis of these data, relates to the distance-to-water covariate. We find that T. carnosus plants are generally healthier when they are further away from the water. 5. We suggest that this may be the result of a combination of (1) plants having alternative rooting strategies depending on how close to water they grow and (2) the rooting strategy determining how well the plants were able to tolerate an unusually dry summer. 6. We anticipate INLA becoming widely used within spatial ecological analysis over the next decade and suggest that both ecologists and statisticians will benefit greatly from working collaboratively to further develop and apply these emerging statistical methods.

Genetic analysis of life-history constraint and evolution in a wild ungulate population

2013-06-02T00:31:43Z

Abstract: Trade-offs among life-history traits are central to evolutionary theory. In quantitative genetic terms, trade-offs may be manifested as negative genetic covariances relative to the direction of selection on phenotypic traits. Although the expression and selection of ecologically important phenotypic variation are fundamentally multivariate phenomena, the in situ quantification of genetic covariances is challenging. Even for life-history traits, where well-developed theory exists with which to relate phenotypic variation to fitness variation, little evidence exists from in situ studies that negative genetic covariances are an important aspect of the genetic architecture of life-history traits. In fact, the majority of reported estimates of genetic covariances among life-history traits are positive. Here we apply theory of the genetics and selection of life histories in organisms with complex life cycles to provide a framework for quantifying the contribution of multivariate genetically based relationships among traits to evolutionary constraint. We use a Bayesian framework to link pedigree-based inference of the genetic basis of variation in life-history traits to evolutionary demography theory regarding how life histories are selected. Our results suggest that genetic covariances may be acting to constrain the evolution of female life-history traits in a wild population of red deer Cervus elaphus: genetic covariances are estimated to reduce the rate of adaptation by about 40%, relative to predicted evolutionary change in the absence of genetic covariances. Furthermore, multivariate phenotypic (rather than genetic) relationships among female life-history traits do not reveal this constraint.

Vocal copying of individually distinctive signature whistles in bottlenose dolphins

2013-03-17T19:01:00Z

Abstract: Vocal learning is relatively common in birds but less so in mammals. Sexual selection and individual or group recognition have been identified as major forces in its evolution. While important in the development of vocal displays, vocal learning also allows signal copying in social interactions. Such copying can function in addressing or labelling selected conspecifics. Most examples of addressing in non-humans come from bird song, where matching occurs in an aggressive context. However, in other animals, addressing with learned signals is very much an affiliative signal. We studied the function of vocal copying in a mammal that shows vocal learning as well as complex cognitive and social behaviour, the bottlenose dolphin (Tursiops truncatus). Copying occurred almost exclusively between close associates such as mother–calf pairs and male alliances during separation and was not followed by aggression. All copies were clearly recognizable as such because copiers consistently modified some acoustic parameters of a signal when copying it. We found no evidence for the use of copying in aggression or deception. This use of vocal copying is similar to its use in human language, where the maintenance of social bonds appears to be more important than the immediate defence of resources.

A class of 5-nitro-2-furancarboxylamides with potent trypanocidal activity against Trypanosoma brucei in vitro

2013-05-12T04:36:57Z

Abstract: Recently, the World Health Organization approved the nifurtimox–eflornithine combination therapy for the treatment of human African trypanosomiasis, renewing interest in nitroheterocycle therapies for this and associated diseases. In this study, we have synthesized a series of novel 5-nitro-2-furancarboxylamides that show potent trypanocidal activity, 1000-fold more potent than nifurtimox against in vitro Trypanosoma brucei with very low cytotoxicity against human HeLa cells. More importantly, the most potent analogue showed very limited cross-resistance to nifurtimox-resistant cells and vice versa. This implies that our novel, relatively easy to synthesize and therefore cheap, 5-nitro-2-furancarboxylamides are targeting a different, but still essential, biochemical process to those targeted by nifurtimox or its metabolites in the parasites. The significant increase in potency (smaller dose probably required) has the potential for greatly reducing unwanted side effects and also reducing the likelihood of drug resistance. Collectively, these findings have important implications for the future therapeutic treatment of African sleeping sickness.

Fast silencing reveals a lost role for reciprocal inhibition in locomotion

2013-02-18T10:01:02Z

Abstract: Summary Alternating contractions of antagonistic muscle groups during locomotion are generated by spinal “half-center” networks coupled in antiphase by reciprocal inhibition. It is widely thought that reciprocal inhibition only coordinates the activity of these muscles. We have devised two methods to rapidly and selectively silence neurons on just one side of Xenopus tadpole spinal cord and hindbrain, which generate swimming rhythms. Silencing activity on one side led to rapid cessation of activity on the other side. Analyses reveal that this resulted from the depression of reciprocal inhibition connecting the two sides. Although critical neurons in intact tadpoles are capable of pacemaker firing individually, an effect that could support motor rhythms without inhibition, the swimming network itself requires ∼23 min to regain rhythmic activity after blocking inhibition pharmacologically, implying some homeostatic changes. We conclude therefore that reciprocal inhibition is critical for the generation of normal locomotor rhythm.

The role of endosymbionts in the evolution of haploid-male genetic systems in scale insects (Coccoidea)

2013-02-13T10:31:02Z

Abstract: There is an extraordinary diversity in genetic systems across species, but this variation remains poorly understood. In part, this is because the mechanisms responsible for transitions between systems are often unknown. A recent hypothesis has suggested that conflict between hosts and endosymbiotic microorganisms over transmission could drive the transition from diplodiploidy to systems with male haploidy (haplodiploidy, including arrhenotoky and paternal genome elimination [PGE]). Here, we present the first formal test of this idea with a comparative analysis across scale insects (Hemiptera: Coccoidea). Scale insects are renowned for their large variation in genetic systems, and multiple transitions between diplodiploidy and haplodiploidy have taken place within this group. Additionally, most species rely on endosymbiotic microorganisms to provide them with essential nutrients lacking in their diet. We show that species harboring endosymbionts are indeed more likely to have a genetic system with male haploidy, which supports the hypothesis that endosymbionts might have played a role in the transition to haplodiploidy. We also extend our analysis to consider the relationship between endosymbiont presence and transitions to parthenogenesis. Although in scale insects there is no such overall association, species harboring eukaryote endosymbionts were more likely to be parthenogenetic than those with bacterial symbionts. These results support the idea that intergenomic conflict can drive the evolution of novel genetic systems and affect host reproduction.

Functional analysis of Leishmania cyclopropane fatty acid synthetase

2013-02-11T16:31:06Z

Abstract: The single gene encoding cyclopropane fatty acid synthetase (CFAS) is present in Leishmania infantum, L. mexicana and L. braziliensis but absent from L. major, a causative agent of cutaneous leishmaniasis. In L. infantum, usually causative agent of visceral leishmaniasis, the CFAS gene is transcribed in both insect (extracellular) and host (intracellular) stages of the parasite life cycle. Tagged CFAS protein is stably detected in intracellular L. infantum but only during the early log phase of extracellular growth, when it shows partial localisation to the endoplasmic reticulum. Lipid analyses of L. infantum wild type, CFAS null and complemented parasites detect a low abundance CFAS-dependent C19 Delta fatty acid, characteristic of a cyclopropanated species, in wild type and add-back cells. Sub-cellular fractionation studies locate the C19 Delta fatty acid to both ER and plasma membrane-enriched fractions. This fatty acid is not detectable in wild type L. major, although expression of the L. infantum CFAS gene in L. major generates cyclopropanated fatty acids, indicating that the substrate for this modification is present in L. major, despite the absence of the modifying enzyme. Loss of the L. infantum CFAS gene does not affect extracellular parasite growth, phagocytosis or early survival in macrophages. However, while endocytosis is also unaffected in the extracellular CFAS nulls, membrane transporter activity is defective and the null parasites are more resistant to oxidative stress. Following infection in vivo, L. infantum CFAS nulls exhibit lower parasite burdens in both the liver and spleen of susceptible hosts but it has not been possible to complement this phenotype, suggesting that loss of C19 Delta fatty acid may lead to irreversible changes in cell physiology that cannot be rescued by re-expression. Aberrant cyclopropanation in L. major decreases parasite virulence but does not influence parasite tissue tropism.

New phosphine-diamine and phosphine-amino-alcohol tridentate ligands for ruthenium catalysed enantioselective hydrogenation of ketones and a concise lactone synthesis enabled by asymmetric reduction of cyano-ketones

2013-02-11T16:31:05Z

Abstract: Enantioselective hydrogenation of ketones is a key reaction in organic chemistry. In the past, we have attempted to deal with some unsolved challenges in this arena by introducing chiral tridentate phosphine-diamine/Ru catalysts. New catalysts and new applications are presented here, including the synthesis of phosphine-amino-alcohol P,N,OH ligands derived from (R,S)-1-amino-2-indanol, (S,S)-1-amino-2-indanol and a new chiral P,N,N ligand derived from (R,R)-1,2-diphenylethylenediamine. Ruthenium pre-catalysts of type [RuCl2(L)(DMSO)] were isolated and then examined in the hydrogenation of ketones. While the new P,N,OH ligand based catalysts are poor, the new P,N,N system gives up to 98% e.e. on substrates that do not react at all with most catalysts. A preliminary attempt at realising a new delta lactone synthesis by organocatalytic Michael addition between acetophenone and acrylonitrile, followed by asymmetric hydrogenation of the nitrile functionalised ketone is challenging in part due to the Michael addition chemistry, but also since Noyori pressure hydrogenation catalysts gave massively reduced reactivity relative to their performance for other acetophenone derivatives. The Ru phosphine-diamine system allowed quantitative conversion and around 50% e.e. The product can be converted into a delta lactone by treatment with KOH with complete retention of enantiomeric excess. This approach potentially offers access to this class of chiral molecules in three steps from the extremely cheap building blocks acrylonitrile and methyl-ketones; we encourage researchers to improve on our efforts in this potentially useful but currently flawed process.

The AEROPATH project targeting Pseudomonas aeruginosa : crystallographic studies for assessment of potential targets in early-stage drug discovery

2013-05-07T14:38:46Z

Abstract: Bacterial infections are increasingly difficult to treat owing to the spread of antibiotic resistance. A major concern is Gram-negative bacteria, for which the discovery of new antimicrobial drugs has been particularly scarce. In an effort to accelerate early steps in drug discovery, the EU-funded AEROPATH project aims to identify novel targets in the opportunistic pathogen Pseudomonas aeruginosa by applying a multidisciplinary approach encompassing target validation, structural characterization, assay development and hit identification from small-molecule libraries. Here, the strategies used for target selection are described and progress in protein production and structure analysis is reported. Of the 102 selected targets, 84 could be produced in soluble form and the de novo structures of 39 proteins have been determined. The crystal structures of eight of these targets, ranging from hypothetical unknown proteins to metabolic enzymes from different functional classes (PA1645, PA1648, PA2169, PA3770, PA4098, PA4485, PA4992 and PA5259), are reported here. The structural information is expected to provide a firm basis for the improvement of hit compounds identified from fragment-based and high-throughput screening campaigns.

A small-molecule inhibitor of T. gondii motility induces the posttranslational modification of myosin light chain-1 and inhibits myosin motor activity

2013-05-12T04:33:58Z

Abstract: Toxoplasma gondii is an obligate intracellular parasite that enters cells by a process of active penetration. Host cell penetration and parasite motility are driven by a myosin motor complex consisting of four known proteins: TgMyoA, an unconventional Class XIV myosin; TgMLC1, a myosin light chain; and two membrane-associated proteins, TgGAP45 and TgGAP50. Little is known about how the activity of the myosin motor complex is regulated. Here, we show that treatment of parasites with a recently identified small-molecule inhibitor of invasion and motility results in a rapid and irreversible change in the electrophoretic mobility of TgMLC1. While the precise nature of the TgMLC1 modification has not yet been established, it was mapped to the peptide Val46-Arg59. To determine if the TgMLC1 modification is responsible for the motility defect observed in parasites after compound treatment, the activity of myosin motor complexes from control and compound-treated parasites was compared in an in vitro motility assay. TgMyoA motor complexes containing the modified TgMLC1 showed significantly decreased motor activity compared to control complexes. This change in motor activity likely accounts for the motility defects seen in the parasites after compound treatment and provides the first evidence, in any species, that the mechanical activity of Class XIV myosins can be modulated by posttranslational modifications to their associated light chains.

A family of spatial biodiversity measures based on graphs

2013-05-12T04:01:53Z

Abstract: While much research in ecology has focused on spatially explicit modelling as well as on measures of biodiversity, the concept of spatial (or local) biodiversity has been discussed very little. This paper generalises existing measures of spatial biodiversity and introduces a family of spatial biodiversity measures by flexibly defining the notion of the individuals’ neighbourhood within the framework of graphs associated to a spatial point pattern. We consider two non-independent aspects of spatial biodiversity, scattering, i.e. the spatial arrangement of the individuals in the study area and exposure, the local diversity in an individual’s neighbourhood. A simulation study reveals that measures based on the most commonly used neigh-bourhood defined by the geometric graph do not distinguish well between scattering and exposure. This problem is much less pronounced when other graphs are used. In an analysis of the spatial diversity in a rainforest, the results based on the geometric graph have been shown to spuriously indicate a decrease in spatial biodiversity when no such trend was detected by the other types of neighbourhoods. We also show that the choice neighbourhood markedly impacts on the classification of species according to how strongly and in what way different species spatially structure species diversity. Clearly, in an analysis of spatial or local diversity an appropriate choice of local neighbourhood is crucial in particular in terms of the biological interpretation of the results. Due to its general definition, the approach discussed here offers the necessary flexibility that allows suitable and varying neighbourhood structures to be chosen.

Scripts and politics in modern Central Europe

2013-02-08T15:31:01Z

Abstract: At present two scripts are employed in Central Europe, Latin and Cyrillic, or three,if we include Greece in the region. In this article I set out to problematise this oversimplisticpicture drawing at examples from the past and pointing to various politicaland identificational uses of scripts today. Until the mid-20th century, also other scripts(and different types of the Latin and Cyrillic script, for that matter) were used forofficial purposes and in book production, namely Arabic, Armenian, Church Cyrillic,Gothic and Hebrew. In addition, Glagolitic and Runes (both Nordic and Hungarian)were sometimes recalled for ideological reasons. Each of these scripts was used forwriting in numerous languages. Initially, script choices were dictated by religion(Latin letters for Western Christianity, Church Cyrillic for Slavophone OrthodoxChristians, or the Arabic writing system for Muslims), usually connected to a holybook in an ecclesiastical language committed to parchment in a specific script. Whenvernaculars began to make an appearance in writing, especially in the 16th centuryand later, their users stuck to the scripts of their holy books. Two factors, the processof building ethnolinguistically defined nation-states and changing ideas about whatmodernity should be about in the sphere of culture, radically limited the number ofscripts in official and de facto use. Only in Bosnia-Hercegovina, Kosovo, Macedonia,Moldova, Montenegro and Ukraine are two scripts in official use, to varying degrees inthe different countries. The European Union already uses three official scripts, Cyrillic,Greek and Latin; if its actions follow its words and it admits some or all of thesestates to membership, it stands a good chance of reviving the tradition of Europeanmultiscripturality, alongside its legally enshrined commitment to multilingualism.

Multispecies functional response of the minke whale Balaenoptera acutorostrata based on small-scale foraging studies

2013-05-12T02:03:26Z

Abstract: Atlantic minke whales are important predators in the Barents Sea ecosystem; capelin Mallotus villosus, krill Thysanoessa sp. and Meganyctephanes norvegica and herring Clupea harengus are their major prey. Their consumption of commercial species may present an economic problem for the local fishery. In order to estimate this consumption and understand the potential consequences for prey dynamics, it is essential to determine the multispecies functional response of the whales. The parameterisation of a functional response requires measurements of consumption rates and prey availability. In this localised study, undigested stomach contents were used to assess the amount of each prey that had been consumed immediately prior to capture. To determine the availability of prey to the whales, standard acoustic surveys were run in the same area within 2 d of the capture of the whales. The spatial distribution of prey was modelled using generalised additive models (GAMs). In order to generate a measure of prey availability and the uncertainty in this value, a simple model was assumed for whale movement, and prey abundance was sampled over space according to a Gaussian kernel. A multispecies functional response (MSFR) model was then fitted to the consumption and prey availability data using Bayesian methods. Simple simulations, based on the fitted MSFR, indicate that minke whales may deplete local capelin aggregations at small spatial scales. This is the first time that a multispecies functional response has been fitted for a cetacean predator, and the methods outlined here may prove useful for modelling marine mammal-fish interactions in other systems.

Estimating demographic parameters for capture-recapture data in the presence of multiple mark types

2013-05-19T00:32:10Z

Abstract: In mark-recapture studies, various techniques can be used to uniquely identify individual animals, such as ringing, tagging or photo-identification using natural markings. In some long-term studies more than one type of marking procedure may be implemented during the study period. In these circumstances, ignoring the different mark types can produce biased survival estimates since the assumption that the different mark types are equally catchable (homogeneous capture probability across mark types) may be incorrect.We implement an integrated approach where we simultaneously analyse data obtained using three different marking techniques, assuming that animals can be cross-classified across the different mark types. We discriminate between competing models using the AIC statistic. This technique also allows us to estimate both relative mark-loss probabilities and relative recapture efficiency rates for the different marking methods.We initially perform a simulation study to explore the different biases that can be introduced if we assume a homogeneous recapture probability over mark type, before applying the method to a real dataset. We make use of data obtained from an intensive long-term observational study of UK female grey seals (Halichoerus grypus) at a single breeding colony, where three different methods are used to identify individuals within a single study: branding, tagging and photo-identification based on seal coat pattern or pelage.

Evolution of ancient functions in the vertebrate insulin-like growth factor system uncovered by study of duplicated salmonid fish genomes

2013-02-07T15:01:03Z

Abstract: Whole genome duplication (WGD) was experienced twice by the vertebrate ancestor (2 rounds; 2R), again by the teleost fish ancestor (3R) and most recently in certain teleost lineages (4R). Consequently, vertebrate gene families are often expanded in 3R and 4R genomes. Arguably, many types of ‘functional divergence’ present across 2R gene families will exceed that between 3R/4R paralogues of genes comprising 2R families. Accordingly, 4R offers a form of replication of 2R. Examining if this concept has implications for molecular evolutionary research, we studied insulin-like growth factor (IGF) binding proteins (IGFBPs), whose six 2R family members carry IGF hormones and regulate interactions between IGFs and IGF1-receptors (IGF1Rs). Using phylogenomic approaches, we resolved the complete IGFBP repertoire of 4R-derived salmonid fishes (nineteen genes; thirteen more than human) and established evolutionary relationships/nomenclature with respect to WGDs. Traits central to IGFBP action were determined for all genes, including atomic interactions in IGFBP-IGF1/IGF2 complexes regulating IGF-IGF1R binding. Using statistical methods, we demonstrate that attributes of these protein interfaces are overwhelming a product of 2R IGFBP family membership, explain 49-68% of variation in IGFBP mRNA concentration in several different tissues and strongly predict the strength and direction of IGFBP transcriptional regulation under differing nutritional-states. The results support a model where vertebrate IGFBP family members evolved divergent structural attributes to provide distinct competition for IGFs with IGF1Rs, pre-disposing different functions in the regulation of IGF-signaling. Evolution of gene expression acted to ensure the appropriate physiological production of IGFBPs according to their structural specializations, leading to optimal IGF-signaling according to nutritional-status and the endocrine/local mode of action. This study demonstrates that relatively recent gene family expansion can facilitate inference of functional evolution within ancient genetic systems. Description: This work was supported by the Marine Alliance for Science and Technology for Scotland pooling initiative, funded by the Scottish Funding Council (grant number HR09011) and contributing institutions.

Every group is a maximal subgroup of the free idempotent generated semigroup over a band

2013-02-07T12:34:51Z

Abstract: Given an arbitrary group G we construct a semigroup of idempotents (band) BG with the property that the free idempotent generated semigroup over BG has a maximal subgroup isomorphic to G. If G is finitely presented then BG is finite. This answers several questions from recent papers in the area.

On disjoint unions of finitely many copies of the free monogenic semigroup

2013-05-28T15:01:01Z

Abstract: Every semigroup which is a finite disjoint union of copies of the free monogenic semigroup (natural numbers under addition) is finitely presented and residually finite.

Damping of kink waves by mode coupling : I. Analytical treatment

2013-02-07T12:34:46Z

Abstract: Aims. To investigate the spatial damping of propagating kink waves in an inhomogeneous plasma. In the limit of a thin tube surrounded by a thin transition layer, an analytical formulation for kink waves driven in from the bottom boundary of the corona is presented. Methods. The spatial form for the damping of the kink mode was investigated using various analytical approximations. When the density ratio between the internal density and the external density is not too large, a simple di.erential-integral equation was used. Approximate analytical solutions to this equation are presented. Results. For the first time, the form of the spatial damping of the kink mode is shown analytically to be Gaussian in nature near the driven boundary. For several wavelengths, the amplitude of the kink mode is proportional to (1 + exp(-z2 /L2 g))/2, where L2g = 16/ǫκ2 k2 . Although the actual value of 16 in Lg depends on the particular form of the driver, this form is very general and its dependence on the other parameters does not change. For large distances, the damping profile appears to be roughly linear exponential decay. This is shown analytically by a series expansion when the inhomogeneous layer width is small enough.

Determination of the spring constants of the higher flexural modes of microcantilever sensors

2013-04-24T14:01:02Z

Abstract: A method for the simultaneous calibration of the spring constants of all flexural modes of microcantilevers is presented. It is based on a flow of gas from a microchannel that interacts with the microcantilever. The gas flow causes a measurable shift in the resonance frequencies of thermal noise spectra of the flexural modes. From the magnitude of the frequency shifts of the individual modes the spring constants can be determined with high accuracy and precision. The method is non-invasive and does not risk damage to the cantilever. Experimental data is presented for several V-shaped and rectangular cantilevers with nominal fundamental spring constants in the range of 0.03-1.75 N/m. The spring constants of the fundamental modes compare favorably to those obtained using the Sader method. The higher modes of oscillation are readily calibrated with experimental uncertainties of 5-10%.

The influence of a fluid-porous interface on solar pond stability

2013-02-07T12:07:19Z

Abstract: The linear instability of the gradient zone of a solar pond containing a fluidporous interface is investigated. It is found that the gradient zone can retain the same stability for lower values of the solute Rayleigh number with the introduction of a porous material compared with a purely fluid layer, whilst maintaining the same lower convective zone temperature. Interestingly, it is also shown that for certain parameter values the penetration of a porous medium into the gradient zone can cause the temperature of the lower convective zone to rise. However, for certain parameter ranges, when the fluid-porous interface is towards the top of the gradient zone, the solar pond can become highly unstable.

Excavating the borders of literary Anglo-Saxonism in nineteenth-century Britain and Australia

2013-02-06T22:01:08Z

Abstract: Comparing nineteenth-century British and Australian Anglo-Saxonist literature enables a "decentered" exploration of Anglo-Saxonism's intersections with national, imperial, and colonial discourses, challenging assumption that this discourse was an uncritical vehicle of English nationalism and British manifest destiny. Far from reflecting a stable imperial center, evocations of 'ancient Englishness' in British literature were polyvalent and self-contesting, while in Australian literature they offered a response to colonization and emerging knowledge about the vast age of Indigenous Australian cultures.

Towards moral and authentic generalization : humanity, individual human beings and distortion

2013-01-29T18:01:02Z

Abstract: The article treats the issue of generality. How may one conceive of the relationship between the uniqueness of individuality and the commonality of the human (species and society) without reduction? Can generalization be made moral – es-chewing stereotypes in society – and can it be made authentic – enacting a human science which treats the individual as a thing-in-itself? Simmel’s seminal inter-vention was to see generality as a necessary kind of distortion. In contrast, this article offers rational models of the one and the whole which expect to retain the uniqueness of the one; and it suggests characteristics of human embodiment (ca-pacities, potentialities) that speak to individuality and generality at the same time. The article ends with a reconsideration of distortion as a humane artistic represen-tation, by way of the work of Stanley Spencer.

Ideals and finiteness conditions for subsemigroups

2013-01-29T17:31:02Z

Abstract: In this paper we consider a number of finiteness conditions for semigroups related to their ideal structure, and ask whether such conditions are preserved by sub- or supersemigroups with finite Rees or Green index. Specific properties under consideration include stability, D=J and minimal conditions on ideals.

Development temperature has persistent effects on muscle growth responses in gilthead sea bream

2013-01-25T14:31:02Z

Abstract: Initially we characterised growth responses to altered nutritional input at the transcriptional and tissue levels in the fast skeletal muscle of juvenile gilthead sea bream. Fish reared at 21–22°C (range) were fed a commercial diet at 3% body mass d−1 (non-satiation feeding, NSF) for 4 weeks, fasted for 4d (F) and then fed to satiation (SF) for 21d. 13 out of 34 genes investigated showed consistent patterns of regulation between nutritional states. Fasting was associated with a 20-fold increase in MAFbx, and a 5-fold increase in Six1 and WASp expression, which returned to NSF levels within 16h of SF. Refeeding to satiation was associated with a rapid (<24 h) 12 to 17-fold increase in UNC45, Hsp70 and Hsp90α transcripts coding for molecular chaperones associated with unfolded protein response pathways. The growth factors FGF6 and IGF1 increased 6.0 and 4.5-fold within 16 h and 24 h of refeeding respectively. The average growth in diameter of fast muscle fibres was checked with fasting and significant fibre hypertrophy was only observed after 13d and 21d SF. To investigate developmental plasticity in growth responses we used the same experimental protocol with fish reared at either 17.5–18.5°C (range) (LT) or 21–22°C (range) (HT) to metamorphosis and then transferred to 21–22°C. There were persistent effects of development temperature on muscle growth patterns with 20% more fibres of lower average diameter in LT than HT group of similar body size. Altering the nutritional input to the muscle to stimulate growth revealed cryptic changes in the expression of UNC45 and Hsp90α with higher transcript abundance in the LT than HT groups, whereas there were no differences in the expression of MAFbx and Six1. It was concluded that myogenesis and gene expression patterns during growth are not fixed, but can be modified by temperature during the early stages of the life cycle.

Prins fluorination cyclisations : Preparation of 4-fluoro-pyran and -piperidine heterocycles

2013-05-12T04:10:08Z

Abstract: The Prins reaction was investigated using BF3 center dot OEt2 as a Lewis acid. It has been recently demonstrated, that if BF3 center dot OEt2 is used in stoichiometric amounts then these reactions generate fluorinated products where the BF3 center dot OEt2 contributes fluoride ion to quench the intermediate carbocations. In this study oxa- and aza-Prins reactions for the synthesis of 4-fluoro-pyrans and -piperidines were investigated. The products were obtained in good yields, but only with moderate diastereoselectivity. These Prins fluorination reactions can be accelerated under microwave conditions. The study extends the Prins fluorination methodology for the generation of the C-F bond in heterocycles.

Living history with Open Virtual Worlds : Reconstructing St Andrews Cathedral as a stage for historic narrative

2013-01-24T10:01:16Z

Abstract: St Andrews Cathedral is located on the East Coast of Scotland, construction started in 1160 and spanned Romanesque and Gothic architectural styles. It was consecrated in 1318, four years after the battle of Bannockburn in the presence of King Robert the Bruce. For several hundred years, the Cathedral was one of the most important religious buildings in Europe and the centre of religious life in Scotland. During the Scottish Reformation, John Knox lead reformers in divesting the Cathedral of much of its finery. Thereafter it fell into disuse and decline. Today the impressive remains only hint at the former glory of this important building. Cultural Heritage encompasses physical aspects such as architecture and artifacts along with less tangible culture such as music, songs and stories. Open virtual worlds offer an extensible collaborative environment for developing historic scenes against the background of which material and ephemeral aspects of cultural heritage associated with a site may be explored through engagement with historic narratives. They offer the potential to reconstruct within a 3D computer environment both the physical structures of the past and important aspects of the light, music and life that once filled those structures. Virtual reconstructions enable scenarios to be created where individual pieces of art can be located and appreciated within the audio, visual and spacial contexts for which they were originally created. Bringing together architecture, sculpture, illumination, stained-glass, music, procession and lighting into a scene which can be explored from multiple spatial perspectives enables holistic experience and appreciation. Historic reconstructions may be created upon virtual stages allowing new and engaging Cultural Heritage perspectives to be accessible to diverse audiences. Through the example of St Andrews Cathedral reconstruction this paper presents an example of Open Virtual Worlds as a technology for supporting the creation and use of virtual reconstructions as a platform that promotes understanding of and engagement with Cultural Heritage. The use contexts discussed range from research based exploration of 3D spaces, to primary schools students using the reconstructions as a backdrop for tag. The digital literacies of the audience and goals of the use case impact on the appropriateness of the user interface. A range of interfaces are explored including games controllers, touch screens, tablets that provide location aware views into the model and hands free gesture control systems.

Optical recombination of biexcitons in semiconductors

2013-01-22T19:31:35Z

Abstract: We calculate the photoluminescence spectrum and lifetime of a biexciton in a semiconductor using Fermi's golden rule. Our biexciton wavefunction is obtained using a Quantum Monte Carlo calculation. We consider a recombination process where one of the excitons within the biexciton annihilates. For hole masses greater than or equal to the electron mass, we find that the surviving exciton is most likely to populate the ground state. We also investigate how the confinement of excitons in a quantum dot would modify the lifetime in the limit of a large quantum dot where confinement principally affects the centre of mass wavefunction. The lifetimes we obtain are in reasonable agreement with experimental values. Our calculation can be used as a benchmark for comparison with approximate methods. Description: 6 pages, 2 figures

Unusual features of pomoviral RNA movement

2013-01-21T16:31:02Z

Abstract: Potato mop-top pomovirus (PMTV) is one of a few viruses that can move systemically in plants in the absence of the capsid protein (CP). Pomoviruses encode the triple gene block genetic module of movement proteins (TGB 1, 2, and 3) and recent research suggests that PMTV RNA is transported either as ribonucleoprotein (RNP) complexes containing TGB1 or encapsidated in virions containing TGB1. Furthermore, there are different requirements for local or systemic (long-distance) movement. Research suggests that nucleolar passage of TGB1 may be important for the long-distance movement of both RNP and virions. Moreover, and uniquely, the long-distance movement of the CP-encoding RNA requires expression of both major and minor CP subunits and is inhibited when only the major CP sub unit is expressed. This paper reviews pomovirus research and presents a current model for RNA movement.

Phasing of muscle gene expression with fasting-induced recovery growth in Atlantic salmon

2013-05-12T03:31:39Z

Abstract: Background: Many fish species experience long periods of fasting in nature often associated with seasonal reductions in water temperature and prey availability or spawning migrations. During periods of nutrient restriction, changes in metabolism occur to provide cellular energy via catabolic processes. Muscle is particularly affected by prolonged fasting as myofibrillar proteins act as a major energy source. To investigate the mechanisms of metabolic reorganisation with fasting and refeeding in a saltwater stage of Atlantic salmon (Salmo salar L.) we analysed the expression of genes involved in myogenesis, growth signalling, lipid biosynthesis and myofibrillar protein degradation and synthesis pathways using qPCR. Results: Hierarchical clustering of gene expression data revealed three clusters. The first cluster comprised genes involved in lipid metabolism and triacylglycerol synthesis (ALDOB, DGAT1 and LPL) which had peak expression 3-14d after refeeding. The second cluster comprised ADIPOQ, MLC2, IGF-I and TALDO1, with peak expression 14-32d after refeeding. Cluster III contained genes strongly down regulated as an initial response to feeding and included the ubiquitin ligases MuRF1 and MAFbx, myogenic regulatory factors and some metabolic genes. Conclusion: Early responses to refeeding in fasted salmon included the synthesis of triacylglycerols and activation of the adipogenic differentiation program. Inhibition of MuRF1 and MAFbx respectively may result in decreased degradation and concomitant increased production of myofibrillar proteins. Both of these processes preceded any increase in expression of myogenic regulatory factors and IGF-I. These responses could be a necessary strategy for an animal adapted to long periods of food deprivation whereby energy reserves are replenished prior to the resumption of myogenesis.

"Adaptive response" - some underlying mechanisms and open questions

2013-01-10T12:01:02Z

Abstract: Organisms are affected by different DNA damaging agents naturally present in the environment or released as a result of human activity. Many defense mechanisms have evolved in organisms to minimize genotoxic damage. One of them is induced radioresistance or adaptive response. The adaptive response could be considered as a nonspecific phenomenon in which exposure to minimal stress could result in increased resistance to higher levels of the same or to other types of stress some hours later. A better understanding of the molecular mechanism underlying the adaptive response may lead to an improvement of cancer treatment, risk assessment and risk management strategies, radiation protection, e. g. of astronauts during long-term space flights. In this mini-review we discuss some open questions and the probable underlying mechanisms involved in adaptive response: the transcription of many genes and the activation of numerous signaling pathways that trigger cell defenses - DNA repair systems, induction of proteins synthesis, enhanced detoxification of free radicals and antioxidant production.

How neurons generate behavior in a hatchling amphibian tadpole : an outline

2013-01-10T11:31:02Z

Abstract: Adult nervous systems are so complex that understanding how they produce behavior remains a real challenge. We chose to study hatchling Xenopus tadpoles where behavior is controlled by a few thousand neurons but there is a very limited number of types of neuron. Young tadpoles can flex, swim away, adjust their trajectory, speed-up and slow-down, stop when they contact support and struggle when grasped. They are sensitive to touch, pressure, noxious stimuli, light intensity and water currents. Using whole-cell recording has led to rapid progress in understanding central networks controlling behavior. Our methods are illustrated by an analysis of the flexion reflex to skin touch. We then define the seven types of neuron that allow the tadpole to swim when the skin is touched and use paired recordings to investigate neuron properties, synaptic connections and activity patterns. Proposals on how the swim network operates are evaluated by experiment and network modeling. We then examine GABAergic inhibitory pathways that control swimming but also produce tonic inhibition to reduce responsiveness when the tadpole is at rest. Finally, we analyze the strong alternating struggling movements the tadpole makes when grasped. We show that the mechanisms for rhythm generation here are very different to those during swimming. Although much remains to be explained, study of this simple vertebrate has uncovered basic principles about the function and organization of vertebrate nervous systems.

Ontogeny of neural circuits underlying spatial memory in the rat

2013-06-04T15:31:00Z

Abstract: Spatial memory is a well-characterized psychological function in both humans and rodents. The combined computations of a network of systems including place cells in the hippocampus, grid cells in the medial entorhinal cortex and head direction cells found in numerous structures in the brain have been suggested to form the neural instantiation of the cognitive map as first described by Tolman in 1948. However, while our understanding of the neural mechanisms underlying spatial representations in adults is relatively sophisticated, we know substantially less about how this network develops in young animals. In this article we briefly review studies examining the developmental time scale that these systems follow. Electrophysiological recordings from very young rats show that directional information is at adult levels at the outset of navigational experience. The systems supporting allocentric memory, however, take longer to mature. This is consistent with behavioral studies of young rats which show that spatial memory based on head direction develops very early but that allocentric spatial memory takes longer to mature. We go on to report new data demonstrating that memory for associations between objects and their spatial locations is slower to develop than memory for objects alone. This is again consistent with previous reports suggesting that adult like spatial representations have a protracted development in rats and also suggests that the systems involved in processing non-spatial stimuli come online earlier.

Aberrant NF-kappaB expression in autism spectrum condition : a mechanism for neuroinflammation

2013-06-16T00:33:55Z

Abstract: Autism spectrum condition (ASC) is recognized as having an inflammatory component. Post-mortem brain samples from patients with ASC display neuroglial activation and inflammatory markers in cerebrospinal fluid, although little is known about the underlying molecular mechanisms. Nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) is a protein found in almost all cell types and mediates regulation of immune response by inducing the expression of inflammatory cytokines and chemokines, establishing a feedback mechanism that can produce chronic or excessive inflammation. This article describes immunodetection and immunofluorescence measurements of NF-κB in human post-mortem samples of orbitofrontal cortex tissue donated to two independent centers: London Brain Bank, Kings College London, UK (ASC: n = 3, controls: n = 4) and Autism Tissue Program, Harvard Brain Bank, USA (ASC: n = 6, controls: n = 5). The hypothesis was that concentrations of NF-κB would be elevated, especially in activated microglia in ASC, and pH would be concomitantly reduced (i.e., acidification). Neurons, astrocytes, and microglia all demonstrated increased extranuclear and nuclear translocated NF-κB p65 expression in brain tissue from ASC donors relative to samples from matched controls. These between-groups differences were increased in astrocytes and microglia relative to neurons, but particularly pronounced for highly mature microglia. Measurement of pH in homogenized samples demonstrated a 0.98-unit difference in means and a strong (F = 98.3; p = 0.00018) linear relationship to the expression of nuclear translocated NF-κB in mature microglia. Acridine orange staining localized pH reductions to lysosomal compartments. In summary, NF-κB is aberrantly expressed in orbitofrontal cortex in patients with ASC, as part of a putative molecular cascade leading to inflammation, especially of resident immune cells in brain regions associated with the behavioral and clinical symptoms of ASC.

Two independent mechanisms for motion-in-depth perception : evidence from individual differences

2013-06-09T00:34:37Z

Abstract: Our forward-facing eyes allow us the advantage of binocular visual information: using the tiny differences between right and left eye views to learn about depth and location in three dimensions. Our visual systems also contain specialized mechanisms to detect motion-in-depth from binocular vision, but the nature of these mechanisms remains controversial. Binocular motion-in-depth perception could theoretically be based on first detecting binocular disparity and then monitoring how it changes over time. The alternative is to monitor the motion in the right and left eye separately and then compare these motion signals. Here we used an individual differences approach to test whether the two sources of information are processed via dissociated mechanisms, and to measure the relative importance of those mechanisms. Our results suggest the existence of two distinct mechanisms, each contributing to the perception of motion-in-depth in most observers. Additionally, for the first time, we demonstrate the relative prevalence of the two mechanisms within a normal population. In general, visual systems appear to rely mostly on the mechanism sensitive to changing binocular disparity, but perception of motion-in-depth is augmented by the presence of a less sensitive mechanism that uses interocular velocity differences. Occasionally, we find observers with the opposite pattern of sensitivity. More generally this work showcases the power of the individual differences approach in studying the functional organization of cognitive systems.

Optical trapping with "on-demand" two-photon luminescence using Cr:LiSAF laser with optically addressed saturable Bragg reflector

2013-05-12T04:36:25Z

Abstract: We demonstrate a diode-pumped Cr:LiSAF laser with controllable and reliable fast switching between its continuous-wave and mode-locked states of operation using an optically-addressed semiconductor Bragg reflector, permitting dyed microspheres to be continuously trapped and monitored using a standard microscope imaging and on-demand two-photon-excited luminescence techniques. (C) 2012 Optical Society of America

Broadly tunable femtosecond mode-locking in a Tm:KYW laser near 2 mu m

2013-05-12T04:36:26Z

Abstract: Efficient mode-locking in a Tm:KY(WO4)(2) laser is demonstrated by using InGaAsSb quantum-well SESAMs. Self-starting ultrashort pulse generation was realized in the 1979-2074 nm spectral region. Maximum average output power up to 411 mW was produced around 1986 nm with the corresponding pulse duration and repetition rate of 549 fs and 105 MHz respectively. Optimised pulse durations of 386 fs were produced with an average power of 235 mW at 2029 nm. (C) 2011 Optical Society of America

While crowding memories came : Edwin Morgan, Old English and nostalgia

2013-01-07T17:01:02Z

Ślōnsk się traci : Silesia is Perishing

2013-01-07T16:41:09Z

Abstract: Afterword

Poland and the Silesians : Minority rights à la carte?

2013-01-07T16:37:07Z

Abstract: The Silesians are an ethnic or national group that coalesced in the nineteenth century. During the subsequent century, they survived repeated divisions of their historical region of Upper Silesia among the nation-states of Czechoslovakia (or today its western half, that is, the Czech Republic), Germany, and Poland, which entailed Czechization, Germanization, and Polonization, respectively. The ideal of ethnolinguistic homogeneity, a typical goal of Central European nationalism, was achieved in post-war Poland. After the end of communism (1989) and the country‟s accession to the European Union (2004), this ideal is still aspired to, though it appears to stand in direct conflict with the values of democracy and rule of law. The Silesians are the largest minority in today‟s Poland and Silesian speakers are the second largest speech community in this country after Polish-speakers. Despite the Silesians‟ wish to be recognized as a minority, expressed clearly in their grassroots initiatives and in the Polish censuses of 2002 and 2011, Poland neither recognizes them nor their language. This inflexible attitude may amount to a breach of the spirit (if not the letter) of the Council of Europe‟s Framework Convention for the Protection of National Minorities and the European Charter for Regional or Minority Languages, both of which Poland signed and ratified. The case of the Silesians is a litmus test of the quality of Polish democracy. In order to resolve the debacle, the article proposes a genuine dialogue between representatives of Silesian organizations and the Polish administration under the guidance of observers and facilitators from the Council of Europe and appropriate international non-governmental organizations.

Mechanisms of gene duplication and translocation and progress towards understanding their relative contributions to animal genome evolution

2013-01-07T16:36:18Z

Abstract: Duplication of genetic material is clearly a major route to genetic change, with consequences for both evolution and disease. A variety of forms and mechanisms of duplication are recognised, operating across the scales of a few base pairs upto entire genomes. With the ever-increasing amounts of gene and genome sequence data that are becoming available, our understanding of the extent of duplication is greatly improving, both in terms of the scales of duplication events as well as their rates of occurrence. An accurate understanding of these processes is vital if we are to properly understand important events in evolution as well as mechanisms operating at the level of genome organisation. Here we will focus on duplication in animal genomes and how the duplicated sequences are distributed, with the aim of maintaining a focus on principles of evolution and organisation that are most directly applicable to the shaping of our own genome.

How many seals were there? The global shelf loss during the Last Glacial Maximum and its effect on the size and distribution of grey seal populations

2013-06-18T15:31:01Z

Abstract: Predicting how marine mammal populations act to habitat changes will be essential for developing conservation management strategies by marine mammal ecologists in the 21st century. Responses to previous environmental change may be informative in the development of predictive models. Here we describe the likely effects of the last ice age on grey seal population size and distribution. We use satellite telemetry data to define grey seal foraging habitat in terms of the temperature and depth ranges exploited by the contemporary populations. We estimate the available extent of such habitat in the North Atlantic at present and at the last glacial maximum (LGM); taking account of glacial and seasonal sea-ice coverage, estimated reductions of sea-level (123m) and seawater temperature hind-casts from GLAMAP-2000. Most of the extensive continental shelf waters (North Sea, Baltic Sea and Scotian Shelf), currently supporting >95% of grey seals, were unavailable at the LGM. A combination of lower sea-level and extensive ice-sheets, massively increased seasonal sea-ice coverage and southerly extent of cold water would have pushed grey seals into areas with no significant shelf waters. The habitat during the LGM might have been as small as 4%, when compared to today’s extent and grey seal populations may have fallen to similarly. An alternative scenario involving a major change to a pelagic/bathy-pelagic foraging niche cannot be discounted. However, hooded seals that appear to out-compete and effectively exclude grey seals from such habitat currently dominate that niche. If as seems likely, the grey seal population fell to very low levels it would have remained low for several thousand years before expanding into current habitats over the last 12000 years or so.

Variation in female grey seal (Halichoerus grypus) reproductive performance correlates to proactive-reactive behavioural types

2013-03-14T16:31:12Z

Abstract: Consistent individual differences (CIDs) in behaviour, indicative of behavioural types or personalities, have been shown in taxa ranging from Cnidaria to Mammalia. However, despite numerous theoretical explanations there remains limited empirical evidence for selective mechanisms that maintain such variation within natural populations. We examined behavioural types and fitness proxies in wild female grey seals at the North Rona breeding colony. Experiments in 2009 and 2010 employed a remotely-controlled vehicle to deliver a novel auditory stimulus to females to elicit changes in pup-checking behaviour. Mothers tested twice during lactation exhibited highly repeatable individual pup-checking rates within and across breeding seasons. Observations of undisturbed mothers (i.e. experiencing no disturbance from conspecifics or experimental test) also revealed CIDs in pup-checking behaviour. However, there was no correlation between an individuals’ pup-checking rate during undisturbed observations with the rate in response to the auditory test, indicating plasticity across situations. The extent to which individuals changed rates of pup-checking from undisturbed to disturbed conditions revealed a continuum of behavioural types from proactive females, who maintained a similar rate throughout, to reactive females, who increased pup-checking markedly in response to the test. Variation in maternal expenditure (daily mass loss rate) was greater among more reactive mothers than proactive mothers. Consequently pups of more reactive mothers had more varied growth rates centred around the long-term population mean. These patterns could not be accounted for by other measured covariates as behavioural type was unrelated to a mother’s prior experience, degree of inter-annual site fidelity, physical characteristics of their pupping habitat, pup sex or pup activity. These findings are consistent with the hypothesis that variation in behavioural types is maintained by spatial and temporal environmental variation combined with limits to phenotype-environment matching.

Coordinatively unsaturated ruthenium complexes as efficient alkyne-azide cycloaddition catalysts

2013-05-12T04:10:51Z

Abstract: The performance of 16-electron ruthenium complexes with the general formula Cp*Ru(L)X (in which L = phosphine or N-heterocyclic carbene ligand; X = Cl or OCH2CF3) was explored in azide−alkyne cycloaddition reactions that afford the 1,2,3- triazole products. The scope of the Cp*Ru(PiPr3)Cl precatalyst was investigated for terminal alkynes leading to new 1,5-disubstituted 1,2,3-triazoles in high yields. Mechanistic studies were conducted and revealed a number of proposed intermediates. Cp*Ru- (PiPr3)(η2-HCCPh)Cl was observed and characterized by 1H, 13C, and 31P NMR at temperatures between 273 and 213 K. A rare example of N,N-κ2-phosphazide complex, Cp*Ru(κ2-iPr3PN3Bn)Cl, was fully characterized, and a single-crystal X-ray diffraction structure was obtained. DFT calculations describe a complete map of the catalytic reactivity with phenylacetylene and/or benzylazide.

Czyżby straszliwe języków pomieszanie w jednoczącej się Europie?

2012-12-19T13:31:01Z

What is biodiversity?

2013-05-12T04:04:03Z

The geometric mean of relative abundance indices : a biodiversity measure with a difference

2012-12-19T11:01:02Z

Abstract: The 2010 Biodiversity Target of the Convention on Biological Diversity (CBD), set in 2002, which stated that there should be ‘a significant reduction of the current rate of biodiversity loss' by 2010, highlighted the need for informative and tractable metrics that can be used to evaluate change in biological diversity. While the subsequent Aichi 2020 targets are more wide-ranging, they also seek to reduce the rate of biodiversity loss. The geometric mean of relative abundance indices, G, is increasingly being used to examine trends in biological diversity and to assess whether biodiversity targets are being met. Here, we explore the mathematical and statistical properties of G that make it useful for judging temporal change in biological diversity, and we discuss its advantages and limitations relative to other measures. We demonstrate that the index reflects trends in both abundance and evenness, and that it is not prone to bias when detectability of individuals varies by species. We note that it allows data from different surveys to be combined to generate a composite index. However, the index exhibits high variance and unstable behaviour when rarely-recorded species are included in the analyses. Read More: http://www.esajournals.org/doi/abs/10.1890/ES11-00186.1

Local and regional rarity in a diverse tropical fish assemblage

2013-05-12T04:14:38Z

Abstract: Because most species in an ecological assemblage are rare, much of the species richness we value is due to taxa with few individuals or a restricted distribution. It has been apparent since the time of ecological pioneers such as Bates and Darwin that tropical systems have disproportionately large numbers of rare species, yet the distribution and abundance patterns of these species remain largely unknown. Here, we examine the diversity of freshwater fish in a series of lakes in the Amazonian várzea, and relate relative abundance, both as numbers of individuals and as biomass, to the occurrence of species in space and time. We find a bimodal relationship of occurrence that distinguishes temporally and spatially persistent species from those that are infrequent in both space and time. Logistic regression reveals that information on occurrence helps distinguish those species that are rare in this locality but abundant elsewhere, from those that are rare throughout the region. These results form a link between different approaches used to evaluate commonness and rarity. In doing so, they provide a tool for identifying species of high conservation priority in poorly documented but species rich localities.

The global regime of language recognition

2012-12-18T17:01:02Z

Abstract: There is no universally accepted working linguistic definition of a language; the distinction between a dialect and a language is a political question. On the basis of a discussion of this problem, the article proposes that the ISO 639 family of standards, issued by the International Organization for Standardization (ISO), amounts to the backbone of an emerging global regime of language recognition. This regime is being rapidly coaxed into being by the booming IT industry and by the Internet, both of which require clear-cut and uniform standards on languages and their scripts in order to function efficiently and profitably. A potentially undesirable and divisive foundation of the regulatory regime, stemming from and meeting the distinctive sectoral purposes of the world of Evangelicalism and Bible translation, is a hurdle to be overcome in achieving a universally accepted system of language standards. Despite efforts by other actors, there is no viable secular alternative in prospect, because the religiously-grounded system has an established and substantial “first mover” advantage in the field.

Contracting institutions and development

2012-12-17T17:31:01Z

Abstract: The quality of contracting institutions has been thought to be of second-order importance next to the impact that good property rights institutions can have on long- run growth. Using a large range of proxies for each type of institution, we find a robust $negative$ link between the quality of contracting institutions and long-run growth when we condition on property rights and a number of additional macroeconomic variables. Although the result remains something of a puzzle, we present evidence which suggests that only when property rights institutions are good do contracting institutions appear also to be good for development. Good contracting institutions can reduce long-run growth when property rights are not secured, presumably because the gains from the (costly) contracting institutions cannot be realised. This suggests that contracting institutions can benefit growth, and that the sequence of institutional change can matter.

Using INLA to fit a complex point process model with temporally varying effects – a case study

2012-12-17T16:01:01Z

Abstract: Integrated nested Laplace approximation (INLA) provides a fast and yet quite exact approach to fitting complex latent Gaussian models which comprise many statistical models in a Bayesian context, including log Gaussian Cox processes. This paper discusses how a joint log Gaussian Cox process model may be fitted to independent replicated point patterns. We illustrate the approach by fitting a model to data on the locations of muskoxen (Ovibos moschatus) herds in Zackenberg valley, Northeast Greenland and by detailing how this model is specified within the R-interface R-INLA. The paper strongly focuses on practical problems involved in the modelling process, including issues of spatial scale, edge effects and prior choices, and finishes with a discussion on models with varying boundary conditions.

A Bayesian approach to fitting Gibbs processes with temporal random effects

2013-05-12T02:32:19Z

Abstract: We consider spatial point pattern data that have been observed repeatedly over a period of time in an inhomogeneous environment. Each spatial point pattern can be regarded as a “snapshot” of the underlying point process at a series of times. Thus, the number of points and corresponding locations of points differ for each snapshot. Each snapshot can be analyzed independently, but in many cases there may be little information in the data relating to model parameters, particularly parameters relating to the interaction between points. Thus, we develop an integrated approach, simultaneously analyzing all snapshots within a single robust and consistent analysis. We assume that sufficient time has passed between observation dates so that the spatial point patterns can be regarded as independent replicates, given spatial covariates. We develop a joint mixed effects Gibbs point process model for the replicates of spatial point patterns by considering environmental covariates in the analysis as fixed effects, to model the heterogeneous environment, with a random effects (or hierarchical) component to account for the different observation days for the intensity function. We demonstrate how the model can be fitted within a Bayesian framework using an auxiliary variable approach to deal with the issue of the random effects component. We apply the methods to a data set of musk oxen herds and demonstrate the increased precision of the parameter estimates when considering all available data within a single integrated analysis.

Electron microscopic studies of growth of nanoscale catalysts and soot particles in a candle flame

2012-12-17T11:31:02Z

Abstract: Scanning electron microscopy and high-resolution transmission electron microscopy have been used to investigate non-classic crystal growth of catalytic nanoparticles, such as zeolites, perovskites, metal and alloy particles. Growth mechanisms of some crystals with novel morphologies, for example, BiOBr flower-like particles and ZnO twin-crystals, have also been studied. A development of sampling method for soot particles inside a candle flame allows us to reveal all four well-known carbon forms, amorphous, graphitic, fullerenic and nanodiamond particles. This article demonstrates that electron microscopy is a powerful tool to study the microstructures of small particles, giving us more freedom to develop new materials.