4,278 research outputs found

    Estudo da diversidade de begomovirus em tomateiro cultivado na região da caatinga do Brasil.

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    O presente trabalho teve como objetivo analisar a diversidade de begomovirus infectando tomateiro no Nordeste brasileiro.Resumo 673-

    Pathophysiological mechanisms in neurodevelopmental disorders caused by rac GTPases dysregulation: What’s behind neuro-RACopathies

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    Rho family guanosine triphosphatases (GTPases) regulate cellular signaling and cytoskele-tal dynamics, playing a pivotal role in cell adhesion, migration, and cell cycle progression. The Rac subfamily of Rho GTPases consists of three highly homologous proteins, Rac 1–3. The proper function of Rac1 and Rac3, and their correct interaction with guanine nucleotide-exchange factors (GEFs) and GTPase-activating proteins (GAPs) are crucial for neural development. Pathogenic variants affecting these delicate biological processes are implicated in different medical conditions in humans, primarily neurodevelopmental disorders (NDDs). In addition to a direct deleterious effect produced by genetic variants in the RAC genes, a dysregulated GTPase activity resulting from an abnormal function of GEFs and GAPs has been involved in the pathogenesis of distinctive emerging conditions. In this study, we reviewed the current pertinent literature on Rac-related disorders with a primary neurological involvement, providing an overview of the current knowledge on the pathophysiological mechanisms involved in the neuro-RACopathies

    Incidência de begomovírus de tomateiro em amostras de soja coletadas durante o período do vazio fitossanitário em 2013/2014.

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    O objetivo deste trabalho foi avaliar a incidência de Tomato severe rugose virus (ToSRV), o principal begomovírus de tomateiro, em amostras de soja coletadas durante o período de vazio fitossanitário do tomateiro (novembro a janeiro).Resumo 15

    A one-sided Prime Ideal Principle for noncommutative rings

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    Completely prime right ideals are introduced as a one-sided generalization of the concept of a prime ideal in a commutative ring. Some of their basic properties are investigated, pointing out both similarities and differences between these right ideals and their commutative counterparts. We prove the Completely Prime Ideal Principle, a theorem stating that right ideals that are maximal in a specific sense must be completely prime. We offer a number of applications of the Completely Prime Ideal Principle arising from many diverse concepts in rings and modules. These applications show how completely prime right ideals control the one-sided structure of a ring, and they recover earlier theorems stating that certain noncommutative rings are domains (namely, proper right PCI rings and rings with the right restricted minimum condition that are not right artinian). In order to provide a deeper understanding of the set of completely prime right ideals in a general ring, we study the special subset of comonoform right ideals.Comment: 38 page

    Theory of Low Temperature Electron Spin Resonance in Half-integer Spin Antiferromagnetic Chains

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    A theory of low temperature (T) electron spin resonance (ESR) in half-integer spin antiferromagnetic chains is developed using field theory methods and avoiding previous approximations. It is compared to experiments on Cu benzoate. Power laws are predicted for the line-width broadening due to various types of anisotropy. At T -> 0, zero width absorption peaks occur in some cases. The second ESR peak in Cu benzoate, observed at T<.76K, is argued not to indicate Neel order as previously claimed, but to correspond to a sine-Gordon "breather" excitation.Comment: 4 pages, REVTEX, 3 PostScript figures embedded in tex

    Modes of ejecta emplacement at Martian craters from laboratory experiments of an expanding vortex ring interacting with a particle layer

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    International audience[1] Ejecta morphologies of many Martian craters indicate fluidized emplacement which differs from ballistic emplacement in dry, airless environments. Double Layered Ejecta craters possess particularly interesting ejecta morphologies: two lobes and radial lineations on their surface, which probably result from gas-dominated radial flow during the emplacement. To examine how a radial flow interacts with surface particles to generate some of the observed morphologies on Mars, we have conducted water tank experiments in which a vortex ring encounters a particle layer. The threshold of particle motion and three interaction modes are described by two dimensionless numbers: particle Shields' parameter and particle Reynolds number. Our results show that gas-dominated flows are possible during cratering and could be used to constrain the ancient Martian environment from observations. Citation: Suzuki, A., I. Kumagai, Y. Nagata, K. Kurita, and O. S. Barnouin-Jha (2007), Modes of ejecta emplacement at Martian craters from laboratory experiments of an expanding vortex ring interacting with a particle layer, Geophys

    EoS of finite density QCD with Wilson fermions by Multi-Parameter Reweighting and Taylor expansion

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    The equation of state (EoS), quark number density and susceptibility at nonzero quark chemical potential μ\mu are studied in lattice QCD simulations with a clover-improved Wilson fermion of 2-flavors and RG-improved gauge action. To access nonzero μ\mu, we employ two methods : a multi-parameter reweighting (MPR) in μ\mu and β\beta and Taylor expansion in μ/T\mu/T. The use of a reduction formula for the Wilson fermion determinant enables to study the reweighting factor in MPR explicitly and heigher-order coefficients in Taylor expansion free from errors of noise method, although calculations are limited to small lattice size. As a consequence, we can study the reliability of the thermodynamical quantities through the consistency of the two methods, each of which has different origin of the application limit. The thermodynamical quantities are obtained from simulations on a 83×48^3\times 4 lattice with an intermediate quark mass(mPS/mV=0.8)m_{\rm PS}/m_{\rm V}=0.8). The MPR and Taylor expansion are consistent for the EoS and number density up to μ/T0.8\mu/T\sim 0.8 and for the number susceptibility up to μ/T0.6\mu/T \sim 0.6. This implies within a given statistics that the overlap problem for the MPR and truncation error for the Taylor expansion method are negligible in these regions. In order to make MPR methods work, the fluctuation of the reweighting factor should be small. We derive the equation of the reweighting line where the fluctuation is small, and show that the equation of the reweighting line is consistent with the fluctuation minimum condition.Comment: 20 pages, 11 figures. Accepted to JHEP. Discussions are added. Figures for Taylor coefficients (Fig. 7) are modifie

    LHR band emissions at mid-latitude and their relationship to ionospheric ELF hiss and relativistic electrons

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    LHR band emissions observed at mid-latitude were investigated using data from the EXOS-C (Ohzora) satellite. A typical feature of the LHR band emissions is a continuous banded structure without burst-like and cut-off features whose center frequency decreases as the satellite moves to higher latitudes. A statistical analysis of the occurrence characteristics of the phenomena showed that mid-latitude LHR emissions are distributed inside the plasmapause during magnetically quiet periods, and the poleward boundary of the emission region moves to lower latitudes as the magnetic activity increases. The altitude distribution of the waves suggests that the propagation in the LHR duct formed horizontally in the mid-latitude upper-ionosphere. The emission is closely related to the occurrence of ionospheric ELF hiss. It is also shown that LHR emissions are commonly observed in the slot region of the radiation belt, and they sometimes accompany the enhancement of the ionospheric electron temperature. The generation of the LHR band emissions is discussed based on the observed characteristics
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