5,909 research outputs found

    Sistema de gestão territorial da faixa de fronteira para a defesa agropecuária.

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    This article presents a technical note about the initiatives developed by Embrapa Satellite Monitoring and the Office of the Secretary of Agricultural Defense - SDA of the Agriculture, Livestock farming and Supplying - MAPA. Those actions are going to structure a system of territorial management of Brazilian borderlands aimaing to support efforts toward the prevention, monitoring and control of the incidence of sanitary risks

    Influência do sistema de produção sobre a formação de osteodermos no couro em jacaré do Pantanal (Caiman yacare, Daudin).

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    Com o objetivo de identificar a influência do sistema de criação na acumulação de cálcio no interior do couro de jacaré do Pantanal, foram obtidos dez animais de cada um dos criatórios situados em Cáceres, MT: Coocrijapan, Jacarepan e Aguacerito. Após o abate e a esfola, as peles foram conservadas por salmouragem e salga, embaladas em sacos de polipropileno e armazenadas em refrigerador a zero grau Celcius. O curtimento foi realizado após o alvejamento e abrandamento dos osteodermos. Foram retiradas amostras do centro da região dorsal dos couros e preparadas para análise em microscopia eletrônica de varredura. As eletromicrografias indicaram remanescentes de estruturas ósseas atacadas por produtos químicos descalcificantes, apresentando vários espaços vazios. Tais estruturas encontram-se envoltas por rede de feixes de fibras de colágeno, formando a derme superior e inferior, e ocupam, aproximadamente, metade da espessura total do couro. Os osteodermos das peles dos animais do criatório Coocrijapan foram mais facilmente atacados quimicamente e resultaram em couros mais macios quando comparados com os couros dos animais dos criatórios Jacarepan e Aguacerito. O sistema de criação adotado pelos criatórios comerciais interfere na formação de cálcio no interior das peles, resultando em peles com osteodermos mais ou menos suscetíveis ao ataque químico e, conseqüentemente, couros com diferentes graus de maciez

    Manejo da irrigação em pivôs centrais no cerrado de Minas Gerais.

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    Anharmonic transitions in nearly dry L-cysteine I

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    Two special dynamical transitions of universal character have been recently observed in macromolecules at TD180220T_{D}\sim 180 - 220 K and T100T^{*}\sim 100 K. Despite their relevance, a complete understanding of the nature of these transitions and their consequences for the bio-activity of the macromolecule is still lacking. Our results and analysis concerning the temperature dependence of structural, vibrational and thermodynamical properties of the orthorhombic polymorph of the amino acid L-cysteine (at a hydration level of 3.5%) indicated that the two referred temperatures define the triggering of very simple and specific events that govern all the biochemical interactions of the biomolecule: activation of rigid rotors (T<TT<T^{*}), phonon-phonon interactions with phonons of water dimer (T<T<TDT^{*}<T<T_{D}), and water rotational barriers surpassing (T>TDT>T_{D}).Comment: 4 pages, 4 figures, submitted to Physical Review Letter

    Immunization and Aging: a Learning Process in the Immune Network

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    The immune system can be thought as a complex network of different interacting elements. A cellular automaton, defined in shape-space, was recently shown to exhibit self-regulation and complex behavior and is, therefore, a good candidate to model the immune system. Using this model to simulate a real immune system we find good agreement with recent experiments on mice. The model exhibits the experimentally observed refractory behavior of the immune system under multiple antigen presentations as well as loss of its plasticity caused by aging.Comment: 4 latex pages, 3 postscript figures attached. To be published in Physical Review Letters (Tentatively scheduled for 5th Oct. issue

    Application of Pseudo-Hermitian Quantum Mechanics to a Complex Scattering Potential with Point Interactions

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    We present a generalization of the perturbative construction of the metric operator for non-Hermitian Hamiltonians with more than one perturbation parameter. We use this method to study the non-Hermitian scattering Hamiltonian: H=p^2/2m+\zeta_-\delta(x+a)+\zeta_+\delta(x-a), where \zeta_\pm and a are respectively complex and real parameters and \delta(x) is the Dirac delta function. For regions in the space of coupling constants \zeta_\pm where H is quasi-Hermitian and there are no complex bound states or spectral singularities, we construct a (positive-definite) metric operator \eta and the corresponding equivalent Hermitian Hamiltonian h. \eta turns out to be a (perturbatively) bounded operator for the cases that the imaginary part of the coupling constants have opposite sign, \Im(\zeta_+) = -\Im(\zeta_-). This in particular contains the PT-symmetric case: \zeta_+ = \zeta_-^*. We also calculate the energy expectation values for certain Gaussian wave packets to study the nonlocal nature of \rh or equivalently the non-Hermitian nature of \rH. We show that these physical quantities are not directly sensitive to the presence of PT-symmetry.Comment: 22 pages, 4 figure

    Never injected, but hepatitis C virus-infected: a study among self-declared never-injecting drug users from the Amsterdam Cohort Studies

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    The aim of this study was to gain insight in transmission routes of hepatitis C virus (HCV) infection among never-injecting drug users (DU) by studying, incidence, prevalence, determinants and molecular epidemiology of HCV infection. From the Amsterdam Cohort Studies among DU, 352 never-injecting DU were longitudinally tested for HCV antibodies. Logistic regression was used to identify factors associated with antibody prevalence. Part of HCV NS5B was sequenced to determine HCV genotype and for phylogenetic analyses, in which sequences were compared with those from injecting DU. HCV antibody prevalence was 6.3% and HCV incidence was 0.49/1000 PY. HIV-positive status, female sex and starting injection drug use during follow-up (a putative marker of past injection drug use), were independently associated with HCV prevalence. The main genotypes found were genotype 3a (50%) and 1a (30%). Phylogenetic analysis revealed that HCV strains in never-injecting DU did not cluster together and did not differ from HCV strains circulating in injecting DU. We found a higher HCV prevalence in never-injecting DU than in the general population. Phylogenetic analysis shows a strong link with the injecting DU population. The increased risk could be related to underreporting of injecting drug use or to household or sexual transmission from injectors to noninjectors. Our findings stress the need for HCV testing of DU who report never injecting, especially given the potential to treat HCV infection effectively

    Draft genome sequences of <i>Pantoea agglomerans</i> and <i>Pantoea vagans</i> isolates associated with termites

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    The genus Pantoea incorporates many economically and clinically important species. The plant-associated species, Pantoea agglomerans and Pantoea vagans, are closely related and are often isolated from similar environments. Plasmids conferring certain metabolic capabilities are also shared amongst these two species. The genomes of two isolates obtained from fungus-growing termites in South Africa were sequenced, assembled and annotated. A high number of orthologous genes are conserved within and between these species. The difference in genome size between P. agglomerans MP2 (4,733,829 bp) and P. vagans MP7 (4,598,703 bp) can largely be attributed to the differences in plasmid content. The genome sequences of these isolates may shed light on the common traits that enable P. agglomerans and P. vagans to co-occur in plant- and insect-associated niches.The Danish Council for Independent Research, Natural Sciences (STENO grant: Michael Poulsen), the National Research Foundation (NRF) (RCA Fellowship: Pieter De Maayer) and the NRF/Dept. of Science and Technology Centre of Excellence in Tree Health Biotechnology (CTHB), South Africa.http://www.standardsingenomics.org/index.php/sigenam2016Forestry and Agricultural Biotechnology Institute (FABI)Microbiology and Plant Patholog
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