Bats respond to polarity of a magnetic field

Bats have been shown to use information from the Earth's magnetic field during orientation. However, the mechanism underlying this ability remains unknown. In this study we investigated whether bats possess a polarity- or inclination-based compass that could be used in orientation. We monitored the hanging position of adult Nyctalus plancyi in the laboratory in the presence of an induced magnetic field of twice Earth-strength. When under the influence of a normally aligned induced field the bats showed a significant preference for hanging at the northern end of their roosting basket. When the vertical component of the field was reversed, the bats remained at the northern end of the basket. However, when the horizontal component of the field was reversed, the bats changed their positions and hung at the southern end of the basket. Based on these results, we conclude that N. plancyi, unlike all other non-mammalian vertebrates tested to date, uses a polarity-based compass during orientation in the roost, and that the same compass is also likely to underlie bats' long-distance navigation abilities.

Sivers effect and transverse single spin asymmetry in e+p(up arrow) -> e+J/psi+X

We discuss the possibility of using electroproduction of J/psi as a probe of gluon Sivers function by measuring single spin asymmetry (SSA) in experiments with transversely polarized protons and electron beams. We estimate SSA for JLab, HERMES, COMPASS, and eRHIC energies using the color evaporation model of charmonium production and find asymmetry up to 25% for certain choices of model parameters which have been used earlier for estimating SSA in the SIDIS and Drell-Yan processes.

Transverse single spin asymmetry in e plus p(up arrow) -> e plus J/psi plus X and transverse momentum dependent evolution of the Sivers function

We extend our analysis of transverse single spin asymmetry in electroproduction of J/psi to include the effect of the scale evolution of the transverse momentum dependent (TMD) parton distribution functions and gluon Sivers function. We estimate single spin asymmetry for JLab, HERMES, COMPASS, and eRHIC energies using the color evaporation model of charmonium production, using an analytically obtained approximate solution of TMD evolution equations discussed in the literature. We find that there is a reduction in the asymmetry compared with our predictions for the earlier case considered by us, wherein the Q(2) dependence came only from DGLAP evolution of the unpolarized gluon densities and a different parametrization of the TMD Sivers function was used.

Transverse single spin asymmetry in e+p↑→e+J/ψ+X and transverse momentum dependent evolution of the Sivers function

We extend our analysis of transverse single spin asymmetry in electroproduction of J/ψ to include the effect of the scale evolution of the transverse momentum dependent (TMD) parton distribution functions and gluon Sivers function. We estimate single spin asymmetry for JLab, HERMES, COMPASS, and eRHIC energies using the color evaporation model of charmonium production, using an analytically obtained approximate solution of TMD evolution equations discussed in the literature. We find that there is a reduction in the asymmetry compared with our predictions for the earlier case considered by us, wherein the Q2 dependence came only from DGLAP evolution of the unpolarized gluon densities and a different parametrization of the TMD Sivers function was used.

Transverse single spin asymmetry in e plus p up arrow -> e plus J/psi plus X and Q(2) evolution of Sivers function-II

We present estimates of single spin asymmetry in the electroproduction of J/psi taking into account the transverse momentum-dependent (TMD) evolution of the gluon Sivers function. We estimate single spin asymmetry for JLab, HERMES, COMPASS and eRHIC energies using the color evaporation model of J/psi. We have calculated the asymmetry using recent parameters extracted by Echevarria et al. using the Collins-Soper-Sterman approach to TMD evolution. These recent TMD evolution fits are based on the evolution kernel in which the perturbative part is resummed up to next-to-leading logarithmic accuracy. We have also estimated the asymmetry by using parameters which had been obtained by a fit by Anselmino et al., using both an exact numerical and an approximate analytical solution of the TMD evolution equations. We find that the variation among the different estimates obtained using TMD evolution is much smaller than between these on one hand and the estimates obtained using DGLAP evolution on the other. Even though the use of TMD evolution causes an overall reduction in asymmetries compared to the ones obtained without it, they remain sizable. Overall, upon use of TMD evolution, predictions for asymmetries stabilize.

Single Spin Asymmetry in Charmonium Production

We present estimates of single spin asymmetry (SSA) in the electroproduction of taking into account the transverse momentum dependent (TMD) evolution of the gluon Sivers function and using Color Evaporation Model of charmonium production. We estimate SSA for JLab, HERMES, COMPASS and eRHIC energies using recent parameters for the quark Sivers functions which are fitted using an evolution kernel in which the perturbative part is resummed up to next-to-leading logarithms accuracy. We find that these SSAs are much smaller as compared to our first estimates obtained using DGLAP evolution but are comparable to our estimates obtained using TMD evolution where we had used approximate analytical solution of the TMD evolution equation for the purpose.

Rational molecular dynamics scheme for predicting optimum concentration loading of nano-additive in phase change materials

The present study deals with the diffusion and phase transition behaviour of paraffin reinforced with carbon nano-additives namely graphene oxide (GO) and surface functionalized single walled carbon nanotubes (SWCNT). Bulk disordered systems of paraffin hydrocarbons impregnated with carbon nano-additives have been generated in realistic equilibrium conformations for potential application as latent heat storage systems. Ab initio molecular dynamics(MD) in conjugation with COMPASS forcefield has been implemented using periodic boundary conditions. The proposed scheme allows determination of optimum nano-additive loading for improving thermo-physical properties through analysis of mass, thermal and transport properties; and assists in determination of composite behaviour and related performance from microscopic point of view. It was observed that nanocomposites containing 7.8% surface functionalised SWCNT and 55% GO loading corresponds to best latent heat storage system. The propounded methodology could serve as a by-pass route for economically taxing and iterative experimental procedures required to attain the optimum composition for best performance. The results also hint at the large unexplored potential of ab-initio classical MD techniques for predicting performance of new nanocomposites for potential phase change material applications. (C) 2015 Author(s).

生物分子在Ni纳米膜表面吸附的力学特性:分子动力学模拟

采用COMPASS力场,通过分子动力学模拟,研究了Ni纳米薄膜的弹性模量的尺寸效应,以及生物分子吸附在Ni表面对其力学性能的影响.计算结果表明,随着厚度的增大,吸附强度也在增强;Ni纳米薄膜的弹性模量随着膜厚的减小而减小.氨基酸在Ni表面的吸附能够提高其弹性模量1～2 GPa,并且表明分子的取向是重要的影响因素.

Workshop governança de processos para os escritórios setoriais de gestão

Relato a respeito do encontro com representantes dos Escritórios Setoriais de Gestão, cujo objetivo foi apresentar os conceitos de governança de processos e sua consequente implementação na ferramenta IBM Compass.

复合材料及其结构的力学进展 （第四册）

Sea-level rise in Hawaii: Implications for future shoreline locations and Hawaii coastal management

Management of coastal development in Hawaii is based on the location of the certified shoreline, which is representative of the upper limit of marine inundation within the last several years. Though the certified shoreline location is significantly more variable than long-term erosion indicators, its migration will still follow the coastline's general trend. The long-term migration of Hawaii’s coasts will be significantly controlled by rising sea level. However, land use decisions adjacent to the shoreline and the shape and nature of the nearshore environment are also important controls to coastal migration. Though each of the islands has experienced local sea-level rise over the course of the last century, there are still locations across the islands of Kauai, Oahu, and Maui, which show long- term accretion or anomalously high erosion rates relative to their regions. As a result, engineering rules of thumb such as the Brunn rule do not always predict coastal migration and beach profile equilibrium in Hawaii. With coastlines facing all points of the compass rose, anthropogenic alteration of the coasts, complex coastal environments such as coral reefs, and the limited capacity to predict coastal change, Hawaii will require a more robust suite of proactive coastal management policies to weather future changes to its coastline. Continuing to use the current certified shoreline, adopting more stringent coastal setback rules similar to Kauai County, adding realistic sea-level rise components for all types of coastal planning, and developing regional beach management plans are some of the recommended adaptation strategies for Hawaii. (PDF contains 4 pages)

Concerning the current conditions and transport of sand in the shallow water areas off the coast of the south-eastern North Sea [Translation from: Hamburger Kustenforschung 29 [pages 41-43 only], 1974]

With the aid of the German Research Association in the central programme 'Sand movements in the German coastal region', an investigation into the current conditions in the shallow water areas of the coasts of the south-eastern North Sea between Sylt and the Weser estuary was carried out by the author. Foundations of the work are 19 continuous current recordings in five profiles normal to the coast from years 1971 to 1973. Off the coasts of the south-eastern North Sea varying tidal currents impinge; they are currents whose directions may vary periodically through all points of the compass. They are caused by the circulating tides in the North Sea (Amphidromien). The turning flow movement experiences a deformation in the very shallow coastal waters, and as it happens the flow turning movement in the case of high tide continues right up onto the outer flats, while here and in the fore-lying shallow water areas around the time of low water (on account of the small depths of waters), there prevails a more variable current. A result of this hydrodynamical procedure is the development of counter currents. This partial translation of the original paper provides the summary of this study of of the mudflat areas between the Elbe and Weser.

Comportamento de pares fêmea-filhote de baleias-franca-austral, Eubalaena australis (Desmoulins, 1822) no litoral centro-sul de Santa Catarina

O litoral centro-sul do estado de Santa Catarina representa a mais importante área de concentração reprodutiva das baleias-franca-austral, Eubalaena australis, no Brasil. O objetivo deste estudo é caracterizar o padrão comportamental dos pares fêmea-filhote que migram para essas áreas ao longo de 10 temporadas reprodutivas (2003 a 2012). Observações realizadas em pontos fixos foram conduzidas de Julho a Novembro, entre 2003 e 2012, de seis a sete vezes por semana, entre as 6:00h e 17:00h. Os dados foram coletados com auxilio de binóculos Pentax 12x55 mm, bússola, relógio digital, e registrados em fichas de campo padronizadas. Os estados comportamentais (natação, descanso e ativo) foram registrados em intervalos de cinco minutos e a frequência de eventos registrada em cada intervalo de cinco minutos. Natação foi o estado comportamental que prevaleceu tanto para fêmeas e filhotes, seguido de descanso e ativo para as fêmeas e seguido de ativo e descanso para os filhotes. A natação e o descanso são importantes para as fêmeas pois exigem menos energia, já que precisam usá-la para atividades das quais a sobrevivência da espécie depende, como parir, amamentar e cuidar dos filhotes. Para os filhotes, o comportamento ativo é mais importante para o seu desenvolvimento motor e preparação para o processo migratório. Os eventos mais expressados por ambos fêmea e filhote foram exposições indefinidas, estas sendo duas vezes maior para os filhotes. Os filhotes apresentaram comportamentos aéreos em taxas maiores do que as fêmeas, o que denota a importância de tais comportamentos no auxílio ao desenvolvimento da coordenação e na aptidão motora e no fortalecimento da musculatura, melhorando a resistência para a migração. A taxa de ocorrência de eventos aéreos para as fêmeas foi geralmente mais baixa, provavelmente na tentativa de desencorajar os comportamentos ativos realizados pelos filhotes. Esses resultados reforçam a importância da área de estudo como área reprodutiva para a espécie. O número de baleias-franca está crescendo na área, bem como o potencial conflito com atividades humanas. Entender os padrões comportamentais dos pares fêmea-filhote de baleias-franca-austral no litoral de Santa Catarina podem servir como valiosas ferramentas para a elaboração de planos de manejo, contribuindo para a conservação da espécie no litoral brasileiro

Caracterização de um sistema digital de aquisição de imagens radiográficas utilizando nêutrons térmicos e raios gama para a inspeção de componentes mecânicos.

Ensaio não destrutivo é uma ferramenta essencial quando um equipamento, dispositivo ou componente não pode ser submetido a procedimentos destrutivos ou invasivos devido a razões de segurança, alto custo ou outras restrições físicas ou logísticas. Dentro deste quadro radiografias por transmissão com raios gama e nêutrons térmicos são técnicas singulares para inspecionar um objeto e desvendar sua estrutura interna devido à capacidade de atravessar uma vasta gama de materiais utilizados na indústria. Grosso modo, raios gama são mais atenuados por materiais pesados enquanto nêutrons térmicos são mais atenuados por materiais mais leves, tornando-as ferramentas complementares. Este trabalho apresenta os resultados obtidos na inspeção de vários componentes mecânicos, através da radiografia por transmissão com nêutrons térmicos e raios gama. O fluxo de nêutrons térmicos de 4,46x105 n.cm-2.s-1 disponível no canal principal do reator de pesquisa Argonauta do Instituto de Engenharia Nuclear foi usado como fonte para as imagens radiográficas com nêutrons. Raios dekeV emitidos pelo 198Au, também produzido no reator, foram usados como fonte de radiação para radiografias . Imaging Plates, especificamente produzidos para operar com nêutrons térmicos ou com raios X, foram empregados como detectores e dispositivos de armazenamento e captação de imagens para cada uma dessas radiações. Esses dispositivos exibem varias vantagens quando comparados ao filme radiográfico convencional. Com efeito, além de maior sensibilidade e serem reutilizáveis não são necessários câmaras escuras e processamento químico para a revelação. Em vez disso, ele é lido por um feixe de laser que libera elétrons armadilhados na rede cristalina durante a exposição à radiação, fornecendo uma imagem final digital. O desempenho de ambos os sistemas de aquisição de imagens, assim constituído, foi avaliado com respeito à sensibilidade, resolução espacial, linearidade e range dinâmico, incluído uma comparação com sistemas radiográficos com nêutrons empregando filmes e folhas de gadolínio como conversor de nêutrons em partículas carregadas. Além desta caracterização, diversos equipamentos e componentes foram radiografados com ambos os sistemas visando-se avaliar suas capacidades de desvendar a estrutura interna desses objetos e detectar estruturas e estados anormais. Dentro desta abordagem, uma neutrongrafia detectou a presença de material cerâmico remanescente empregado como molde no processo de fabricação nos canais de refrigeração de uma aleta do estator de uma turbina tipo turbo-fan, que deveria estar livre desse material. O reostato danificado de um sensor de pressão automotivo, foi identificado por neutrongrafia, embora nesse caso a radiografia também conseguiu realizar essa tarefa com melhor resolução, corroborando assim as curvas de resolução espacial obtidas na caracterização dos dois sistemas. A homogeneidade da distribuição do material encapsulado em uma gaxeta explosiva de chumbo utilizada na indústria aeroespacial foi igualmente verificada por neutrongrafia porque esse metal é relativamente transparente para nêutrons, mas suficientemente opaco para o explosivo rico em hidrogênio. Diversos outros instrumentos e componentes tais como variômetro, altímetro, bússola aeronáutica, injetor automotivo de combustível, foto-camera, disco rígido de computador, motor de passo, conectores eletrônicos e projéteis foram radiografados com ambos os sistemas visando avaliar suas habilidades em desvendar diferentes peculiaridades em função do agente interrogador.

A practical demonstration of scalable, parallel mesh generation

Cambridge Flow Solutions Ltd, Compass House, Vision Park, Cambridge, CB4 9AD, UK Real-world simulation challenges are getting bigger: virtual aero-engines with multistage blade rows coupled with their secondary air systems & with fully featured geometry; environmental flows at meta-scales over resolved cities; synthetic battlefields. It is clear that the future of simulation is scalable, end-to-end parallelism. To address these challenges we have reported in a sequence of papers a series of inherently parallel building blocks based on the integration of a Level Set based geometry kernel with an octree-based cut-Cartesian mesh generator, RANS flow solver, post-processing and geometry management & editing. The cut-cells which characterize the approach are eliminated by exporting a body-conformal mesh driven by the underpinning Level Set and managed by mesh quality optimization algorithms; this permits third party flow solvers to be deployed. This paper continues this sequence by reporting & demonstrating two main novelties: variable depth volume mesh refinement enabling variable surface mesh refinement and a radical rework of the mesh generation into a bottom-up system based on Space Filling Curves. Also reported are the associated extensions to body-conformal mesh export. Everything is implemented in a scalable, parallel manner. As a practical demonstration, meshes of guaranteed quality are generated for a fully resolved, generic aircraft carrier geometry, a cooled disc brake assembly and a B747 in landing configuration. Copyright © 2009 by W.N.Dawes.