Pastagens em sistemas silvipastoris.

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Distribuição de raízes de coqueiro anão verde sob sistemas de irrigação localizada em solo dos tabuleiros costeiros.

Um dos principais problemas no agronegócio do coqueiro anão verde no Distrito de Irrigação Platô de Neópolis, em Sergipe, está relacionado às características físicas e hídricas dos solos dos tabuleiros costeiros. Por serem pobres em nutrientes, apresentarem baixa capacidade de armazenamento de água e, muitas vezes, forte adensamento nas camadas subsuperficiais, esses solos têm grande influência na distribuição do sistema radicular das plantas, sendo esta variável das mais importantes para a definição de sistemas de irrigação eficientes e ajustados ao meio ambiente. O experimento foi conduzido em parceria com a Empresa União, em cuja propriedade é cultivado, entre outras fruteiras, o coqueiro anão verde para produção de água de coco. Foram selecionadas 18 plantas para avaliação do sistema radicular, após 4 anos de aplicação de sistemas de irrigação localizada por gotejamento, gotejamento enterrado e microaspersão. Os resultados do estudo permitiram concluir que os sistemas gotejamento superficial e enterrado são potencialmente mais promissores do que a microaspersão quanto à possibilidade de aprofundamento do sistema radicular do coqueiro anão verde.bitstream/item/33959/1/bp-06.pd

Influence of earth's conductivity and permittivity frequency dependence on overhead transmission lines: analysis for the one - conductor case

In this paper the influence of earth's conductivity and permittivity frequency dependence are evaluated when calculating transversal and longitudinal transmission lines' parameters. The aim is to compare results calculated from the complex plane method and Carson's modified expressions on longitudinal parameters and also between Carson's modified potential-coefficient correction factors and results from approximations methods for transversal admittance parameters. The importance of properly considering the frequency-dependent soil model is presented for oneconductor case, in order to compare the longitudinal and transversal parameters considering the earth's conductivity and permittivity frequency dependence soil model in relation to the common soil representation with a constant conductivity and a permittivity that can be neglected assuming a low frequency approximation.Este trabalho enquadra-se na linha de pesquisa que tem como objetivo a busca de modelos mais precisos para cálculo de parâmetros de linhas aéreas de transmissão na faixa de frequência 0 a 2 MHz. Esta faixa de frequência cobre a maioria das perturbações eletromagnéticas nos sistemas elétricos (manobras, ocorrências de faltas, rejeições de carga, descargas atmosféricas, perturbações harmônicas). Entre 1 Hz e 2 MHz o solo pode ter a condutividade elétrica da mesma ordem de grandeza que o produto entre a constante dielétrica e a frequência angular do sinal incidente no solo, em função da dependência desses parâmetros com a frequência. Consequentemente, as suposições de baixa frequência tradicionalmente adotadas - condutividade do solo constante e permissividade desprezível - podem levar a modelos que não representam de forma adequada a resposta da linha no caso de transitórios rápidos (com espectro de frequência acima de 1 kHz). É apresentado um estudo dos parâmetros de uma linha formada por um único condutor acima de solo condutor imperfeito, - onde a impedância e a admitância de retorno pelo solo são avaliadas através de métodos tradicionais de cálculo e através de integração numérica das formulações de Carson modificadas para inclusão do modelo de solo com parâmetros dependentes da frequência.506522Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

Isotope Shifts of the 6d\,^2D3/2 _{3/2}\, - 7p\,^2P1/2 _{1/2}\, Transition in Trapped Short-Lived 209−214^{209-214}Ra+^+

Laser spectroscopy of short-lived radium isotopes in a linear Paul trap has been performed. The isotope shifts of the 6d\,^2D$_{3/2}\,$ - 7p\,^2P$_{1/2}\,$ transition in $^{209-214}$Ra$^+$ were measured, which are sensitive to the short range part of the atomic wavefunctions. The results are essential experimental input for improving the precision of atomic structure calculation. This is indispensable for parity violation in Ra$^+$ aiming at the determination of the weak mixing angle.Comment: Accepted for publication in Physical Review A as a Rapid Communicatio

First Test of Lorentz Invariance in the Weak Decay of Polarized Nuclei

A new test of Lorentz invariance in the weak interactions has been made by searching for variations in the decay rate of spin-polarized 20Na nuclei. This test is unique to Gamow-Teller transitions, as was shown in the framework of a recently developed theory that assumes a Lorentz symmetry breaking background field of tensor nature. The nuclear spins were polarized in the up and down direction, putting a limit on the amplitude of sidereal variations of the form |(\Gamma_{up} - \Gamma_{down})| / (\Gamma_{up} + \Gamma_{down}) < 3 * 10^{-3}. This measurement shows a possible route toward a more detailed testing of Lorentz symmetry in weak interactions.Comment: 11 pages, 6 figure

Atributos físicos e hídricos de solos cultivados com coqueiro anão verde irrigado no Platô de Neópolis: resultados de pesquisas.

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Differences between <i>Trypanosoma brucei gambiense</i> groups 1 and 2 in their resistance to killing by Trypanolytic factor 1

&lt;p&gt;&lt;b&gt;Background:&lt;/b&gt; The three sub-species of &lt;i&gt;Trypanosoma brucei&lt;/i&gt; are important pathogens of sub-Saharan Africa. &lt;i&gt;T. b. brucei&lt;/i&gt; is unable to infect humans due to sensitivity to trypanosome lytic factors (TLF) 1 and 2 found in human serum. &lt;i&gt;T. b. rhodesiense&lt;/i&gt; and &lt;i&gt;T. b. gambiense&lt;/i&gt; are able to resist lysis by TLF. There are two distinct sub-groups of &lt;i&gt;T. b. gambiense&lt;/i&gt; that differ genetically and by human serum resistance phenotypes. Group 1 &lt;i&gt;T. b. gambiense&lt;/i&gt; have an invariant phenotype whereas group 2 show variable resistance. Previous data indicated that group 1 &lt;i&gt;T. b. gambiense&lt;/i&gt; are resistant to TLF-1 due in-part to reduced uptake of TLF-1 mediated by reduced expression of the TLF-1 receptor (the haptoglobin-hemoglobin receptor (&lt;i&gt;HpHbR&lt;/i&gt;)) gene. Here we investigate if this is also true in group 2 parasites.&lt;/p&gt; &lt;p&gt;&lt;b&gt;Methodology:&lt;/b&gt; Isogenic resistant and sensitive group 2 &lt;i&gt;T. b. gambiense&lt;/i&gt; were derived and compared to other T. brucei parasites. Both resistant and sensitive lines express the &lt;i&gt;HpHbR&lt;/i&gt; gene at similar levels and internalized fluorescently labeled TLF-1 similar fashion to &lt;i&gt;T. b. brucei&lt;/i&gt;. Both resistant and sensitive group 2, as well as group 1 &lt;i&gt;T. b. gambiense&lt;/i&gt;, internalize recombinant APOL1, but only sensitive group 2 parasites are lysed.&lt;/p&gt; &lt;p&gt;&lt;b&gt;Conclusions:&lt;/b&gt; Our data indicate that, despite group 1 &lt;i&gt;T. b. gambiense&lt;/i&gt; avoiding TLF-1, it is resistant to the main lytic component, APOL1. Similarly group 2 &lt;i&gt;T. b. gambiense&lt;/i&gt; is innately resistant to APOL1, which could be based on the same mechanism. However, group 2 &lt;i&gt;T. b. gambiense&lt;/i&gt; variably displays this phenotype and expression does not appear to correlate with a change in expression site or expression of &lt;i&gt;HpHbR&lt;/i&gt;. Thus there are differences in the mechanism of human serum resistance between &lt;i&gt;T. b. gambiense&lt;/i&gt; groups 1 and 2.&lt;/p&gt

Trypanosome Lytic Factor, an Antimicrobial High-Density Lipoprotein, Ameliorates Leishmania Infection

Innate immunity is the first line of defense against invading microorganisms. Trypanosome Lytic Factor (TLF) is a minor sub-fraction of human high-density lipoprotein that provides innate immunity by completely protecting humans from infection by most species of African trypanosomes, which belong to the Kinetoplastida order. Herein, we demonstrate the broader protective effects of human TLF, which inhibits intracellular infection by Leishmania, a kinetoplastid that replicates in phagolysosomes of macrophages. We show that TLF accumulates within the parasitophorous vacuole of macrophages in vitro and reduces the number of Leishmania metacyclic promastigotes, but not amastigotes. We do not detect any activation of the macrophages by TLF in the presence or absence of Leishmania, and therefore propose that TLF directly damages the parasite in the acidic parasitophorous vacuole. To investigate the physiological relevance of this observation, we have reconstituted lytic activity in vivo by generating mice that express the two main protein components of TLFs: human apolipoprotein L-I and haptoglobin-related protein. Both proteins are expressed in mice at levels equivalent to those found in humans and circulate within high-density lipoproteins. We find that TLF mice can ameliorate an infection with Leishmania by significantly reducing the pathogen burden. In contrast, TLF mice were not protected against infection by the kinetoplastid Trypanosoma cruzi, which infects many cell types and transiently passes through a phagolysosome. We conclude that TLF not only determines species specificity for African trypanosomes, but can also ameliorate an infection with Leishmania, while having no effect on T. cruzi. We propose that TLFs are a component of the innate immune system that can limit infections by their ability to selectively damage pathogens in phagolysosomes within the reticuloendothelial system