Supercurrent induced domain wall motion

We study the dynamics of a magnetic domain wall, inserted in, or juxtaposed to, a conventional superconductor, via the passage of a spin polarized current through a FSF junction. Solving the Landau-Lifshitz-Gilbert equation of motion for the magnetic moments we calculate the velocity of the domain wall and compare it with the case of a FNF junction. We find that in several regimes the domain wall velocity is larger when it is driven by a supercurrent.Comment: 10 pages, 8 figure

Temperature dependence of the coercive field in single-domain particle systems

The magnetic properties of Cu97Co3 and Cu90Co10 granular alloys were measured over a wide temperature range (2 to 300K). The measurements show an unusual temperature dependence of the coercive field. A generalized model is proposed and explains well the experimental behavior over a wide temperature range. The coexistence of blocked and unblocked particles for a given temperature rises difficulties that are solved here by introducing a temperature dependent blocking temperature. An empirical factor gamma arise from the model and is directly related to the particle interactions. The proposed generalized model describes well the experimental results and can be applied to other single-domain particle system.Comment: 7 pages, 8 figures, revised version, accepted to Physical Review B on 29/04/200

Marine ecosystem services: Linking indicators to their classification

© 2014 Elsevier Ltd. All rights reserved. There is a multitude of ecosystem service classifications available within the literature, each with its own advantages and drawbacks. Elements of them have been used to tailor a generic ecosystem service classification for the marine environment and then for a case study site within the North Sea: the Dogger Bank. Indicators for each of the ecosystem services, deemed relevant to the case study site, were identified. Each indicator was then assessed against a set of agreed criteria to ensure its relevance and applicability to environmental management. This paper identifies the need to distinguish between indicators of ecosystem services that are entirely ecological in nature (and largely reveal the potential of an ecosystem to provide ecosystem services), indicators for the ecological processes contributing to the delivery of these services, and indicators of benefits that reveal the realized human use or enjoyment of an ecosystem service. It highlights some of the difficulties faced in selecting meaningful indicators, such as problems of specificity, spatial disconnect and the considerable uncertainty about marine species, habitats and the processes, functions and services they contribute to

Scaling solutions from interacting fluids

We examine the dynamical implications of an interaction between some of the fluid components of the universe. We consider the combination of three matter components, one of which is a perfect fluid and the other two are interacting. The interaction term generalizes the cases found in scalar field cosmologies with an exponential potential. We find that attracting scaling solutions are obtained in several regions of parameter space, that oscillating behaviour is possible, and that new curvature scaling solutions exist. We also discuss the inflationary behaviour of the solutions and present some of the constraints on the strength of the coupling, namely those arising from nucleosynthesis.Comment: RevTeX, 21 pages, 8 figure

A density-functional approach to fermionization in the 1D Bose gas

A time-dependent Kohn-Sham scheme for 1D bosons with contact interaction is derived based on a model of spinor fermions. This model is specifically designed for the study of the strong interaction regime close to the Tonks gas. It allows us to treat the transition from the strongly-interacting Tonks-Girardeau to the weakly-interacting quasicondensate regime and provides an intuitive picture of the extent of fermionization in the system. An adiabatic local-density approximation is devised for the study of time-dependent processes. This scheme is shown to yield not only accurate ground-state properties but also overall features of the elementary excitation spectrum, which is described exactly in the Tonks-gas limit.Comment: 15 pages, 3 figures, misprints (of published version) correcte

Coleta de germoplasma de leguminosas no Semi-Árido do Estado da Bahia.

A tradição das famílias rurais do semi-árido nordestino de produzir e guardar sua própria semente em casa tem se consolidado ao longo das décadas, através das práticas de conservação da diversidade agrícola, pela adaptação e seleção de materiais, troca e experimentação do germoplasma, com a comercialização do excedente de produção na comunidade ou em feiras livre. Com o objetivo de coletar essas variedades, ampliando a amostragem dos Bancos de Germoplasma de Feijão, Caupi e Fava, localizados na Embrapa, e identificando preferências das famílias dessa região realizou-se a expedição a Bahia, com apoio da EBDA. Foram coletadas amostras de 91 acessos de germoplasma de feijão, feijão de corda e fava, mantidos por agricultores locais, principalmente para consumo familiar e eventuais trocas com outros agricultores. Observou-se uma grande perda de variabilidade nos últimos anos, decorrente, principalmente, de alterações no regime de chuvas. Ficou evidente, também, a preferência desses consumidores por suas variedades tradicionais, seja por suas características de sabor, seja pelas qualidades agronômicas, e a necessidade de buscar meios para garantir a conservação, em melhores condições técnicas, dos materiais com características de interesse

Produção de óleo de copaíba na região do Tapajós.

bitstream/item/59296/1/CPATU-ComTec103.pd

Consórcio de milho safrinha com espécies forrageiras e adubo verde em Mato Grosso do Sul.

bitstream/item/65313/1/29898.pdfOrganizado por Gessi Ceccon e Luiz Alberto Staut

Static Configurations of Dark Energy and Dark Matter

We study static configurations of dark matter coupled to a scalar field responsible for the dark energy of the Universe. The dark matter is modelled as a Fermi gas within the Thomas-Fermi approximation. The mass of the dark matter particles is a function of the scalar field. We analyze the profile of the dark matter halos in galaxies. In this case our framework is equivalent to the model of the isothermal sphere. In the presence of a scalar field, the velocity of a massive object orbiting the galaxy is not of the order of the typical velocity of the dark matter particles, as in the conventional picture. Instead, it is reduced by a factor that quantifies the dependence of the dark matter mass on the scalar field. This has implications for dark matter searches. We derive new solutions of the Einstein equations which describe compact objects composed of dark matter. Depending on the scale of the dark matter mass, the size of these objects can vary between microscopic scales and cosmological distances. We determine the mass to radius relation and discuss the similarities with conventional neutron stars and exotic astrophysical objects.Comment: 23 pages, 3 figures, minor additions to the tex

Chemical and biological evaluation of rejects from the wood industry.

Este estudo visa a caracterização química e a avaliação da atividade antimicrobiana de extratos obtidos a partir de rejeitos resultantes do beneficiamento de madeiras nobres comercializadas no Paraná: Peroba-Rosa (Aspidosperma sp.), Roxinho (Peltogyne sp.), Jatobá (Hymenaea sp.), Curupixá (Micropholis sp.), Itaúba (Mezilaurus sp.), Cedrilho (Erisma sp.) e Imbúia-do-Norte (Licaria sp.), cujas identificações botânicas basearam-se em estudos anatômicos. Os extratos foram preparados com diversos solventes, analisados por CCD e espectrometria UV/VIS, testando-se contra: Proteus mirabilis ATCC15290, Escherichia coli ATCC25922, Enterobacter aerogenes ATCC13048, Staphylococcus aureus ATCC25923, Micrococcus luteus ATCC9341, Klebsiella pneumoniae ATCC13883, Pseudomonas aeroginosa ATCC27853, e Staphylococcus aureus, Streptococcus mutans e Bacillus cereus isolados da clínica. O extrato etanólico de Peroba-Rosa, contendo alcalóides, apresentou atividade contra P. mirabilis. Os extratos metanólicos do Jatobá, Itaúba e Imbúia, contendo fenóis, e o extrato de Roxinho obtido com acetato de etila contendo fenóis e terpenóides, foram ativos contra K. pneumoniae, M. luteus, E. coli, S. aureus e P. mirabilis. Nenhum dos extratos foi ativo contra P. aeroginosa, S. mutans e E. aerogenes