1,785 research outputs found

    Is high prevalence of Echinococcus multilocularis in wild and domestic animals associated with disease incidence in humans?

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    We investigated a focus of highly endemic Echinococcus multilocularis infection to assess persistence of high endemicity in rural rodents, explore potential for parasite transmission to domestic carnivores, and assess (serologically) putative exposure versus infection frequency in inhabitants of the region. From spring 1993 to spring 1998, the prevalence of E. multilocularis in rodents was 9% to 39% for Arvicola terrestris and 10% to 21% for Microtus arvalis. From June 1996 to October 1997, 6 (7%) of 86 feral dogs and 1 of 33 cats living close to the region tested positive for intestinal E. multilocularis infection. Testing included egg detection by coproscopy, antigen detection by enzyme-linked immunosorbent assay (ELISA), and specific parasite DNA amplification by polymerase chain reaction. Thus, the presence of infected domestic carnivores can increase E. multilocularis exposure risk in humans. A seroepidemiologic survey of 2,943 blood donors in the area used specific Em2-ELISA. Comparative statistical analyses of seroprevalence and clinical incidence showed an increase in Em2-seroprevalence from 1986 and 1996-97 but no increase in clinical incidence of alveolar hydatid disease

    Effects of different humic substances concentrations on root anatomy and Cd accumulation in seedlings of Avicennia germinans (black mangrove).

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    This study explores, in controlled conditions, the effect of humic substances on Avicennia germinans seedlings, with or without cadmium contamination. Humic compounds significantly changed plant root architecture, and, when coupled with cadmium, root anatomy and Cortex to Vascular Cylinder diameter ratio

    Resposta de diferentes genótipos de tomateiro micro-Tom à adubação com fertilizante organomineral.

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    Com a finalidade de determinar se a utilização do fertilizante organomineral (FOM) resulta em incremento de produção no tomateiro, realizou-se um experimento em em casa de vegetação com tomateiro 'Micro-Tom' WT (WILD TYPE) como genótipo controle e o mutante dgt (diageotropica) pouco sensível ao hormômio auxina (AIA)

    Precision Measurement of the Neutron Spin Asymmetry A1nA_1^n and Spin-Flavor Decomposition in the Valence Quark Region

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    We have measured the neutron spin asymmetry A1nA_1^n with high precision at three kinematics in the deep inelastic region at x=0.33x=0.33, 0.47 and 0.60, and Q2=2.7Q^2=2.7, 3.5 and 4.8 (GeV/c)2^2, respectively. Our results unambiguously show, for the first time, that A1nA_1^n crosses zero around x=0.47x=0.47 and becomes significantly positive at x=0.60x=0.60. Combined with the world proton data, polarized quark distributions were extracted. Our results, in general, agree with relativistic constituent quark models and with perturbative quantum chromodynamics (pQCD) analyses based on the earlier data. However they deviate from pQCD predictions based on hadron helicity conservation.Comment: 5 pages, 2 figures, this is the final version appeared in Phys. Rev. Let

    Precision Measurement of the Neutron Spin Asymmetries and Spin-dependent Structure Functions in the Valence Quark Region

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    We report on measurements of the neutron spin asymmetries A1,2nA_{1,2}^n and polarized structure functions g1,2ng_{1,2}^n at three kinematics in the deep inelastic region, with x=0.33x=0.33, 0.47 and 0.60 and Q2=2.7Q^2=2.7, 3.5 and 4.8 (GeV/c)2^2, respectively. These measurements were performed using a 5.7 GeV longitudinally-polarized electron beam and a polarized 3^3He target. The results for A1nA_1^n and g1ng_1^n at x=0.33x=0.33 are consistent with previous world data and, at the two higher xx points, have improved the precision of the world data by about an order of magnitude. The new A1nA_1^n data show a zero crossing around x=0.47x=0.47 and the value at x=0.60x=0.60 is significantly positive. These results agree with a next-to-leading order QCD analysis of previous world data. The trend of data at high xx agrees with constituent quark model predictions but disagrees with that from leading-order perturbative QCD (pQCD) assuming hadron helicity conservation. Results for A2nA_2^n and g2ng_2^n have a precision comparable to the best world data in this kinematic region. Combined with previous world data, the moment d2nd_2^n was evaluated and the new result has improved the precision of this quantity by about a factor of two. When combined with the world proton data, polarized quark distribution functions were extracted from the new g1n/F1ng_1^n/F_1^n values based on the quark parton model. While results for Δu/u\Delta u/u agree well with predictions from various models, results for Δd/d\Delta d/d disagree with the leading-order pQCD prediction when hadron helicity conservation is imposed.Comment: A typing error in A_\parallel(3He) at x=0.47 in Table VII of Phys. Rev. C has been noticed and correcte

    Mycorrhizal association in wheat genotypes submitted to variable irrigation in the Brazilian Cerrado.

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    Mycorrhizal association contributes to plant growth, influencing tolerance to abiotic stresses such as water deficit. There is considerable variation in infection by arbuscular mycorrhizal fungi (AMF) in cultivars of the same crop, but there is little information regarding these differences in wheat. The objective of this work was to evaluate the influence of water deficit on the arbuscular mycorrhizal association in wheat genotypes in the Cerrado region and the association between soil attributes and mycorrhizal colonization. The experiment was conducted in a no-till system, using different water regimes. The experimental design was a randomized block with subdivided plots scheme, with 12 treatments and 3 repetitions. The plots consisted of 4 wheat genotypes and the subplots included 3 water regimes. Mycorrhizal colonization, soil microbial biomass carbon, total soil organic carbon, easily extractable glomalin-related soil protein, spore number and AMF species diversity were evaluated. Mycorrhizal colonization was not influenced by wheat genotypes, but it was favored by the higher water regime, being 44.8% higher when compared to the lower water regime. The soil moisture was positively correlated with the soil attributes with the exception of the number of AMF spores. The community of AMF associated with wheat genotypes was similar, comprising of 12 species, predominantly Claroideoglomus etunicatum and Glomus macrocarpum. The low variation among wheat genotypes for AMF diversity suggests no selective influence of the plants on the AMF community in the area of the study. Water regime was shown to be a dominant factor in mycorrhizal association

    Measurement of Semileptonic Branching Fractions of B Mesons to Narrow D** States

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    Using the data accumulated in 2002-2004 with the DO detector in proton-antiproton collisions at the Fermilab Tevatron collider with centre-of-mass energy 1.96 TeV, the branching fractions of the decays B -> \bar{D}_1^0(2420) \mu^+ \nu_\mu X and B -> \bar{D}_2^{*0}(2460) \mu^+ \nu_\mu X and their ratio have been measured: BR(\bar{b}->B) \cdot BR(B-> \bar{D}_1^0 \mu^+ \nu_\mu X) \cdot BR(\bar{D}_1^0 -> D*- pi+) = (0.087+-0.007(stat)+-0.014(syst))%; BR(\bar{b}->B)\cdot BR(B->D_2^{*0} \mu^+ \nu_\mu X) \cdot BR(\bar{D}_2^{*0} -> D*- \pi^+) = (0.035+-0.007(stat)+-0.008(syst))%; and (BR(B -> \bar{D}_2^{*0} \mu^+ \nu_\mu X)BR(D2*0->D*- pi+)) / (BR(B -> \bar{D}_1^{0} \mu^+ \nu_\mu X)\cdot BR(\bar{D}_1^{0}->D*- \pi^+)) = 0.39+-0.09(stat)+-0.12(syst), where the charge conjugated states are always implied.Comment: submitted to Phys. Rev. Let
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