11,206 research outputs found

    Assessment of seismic performance of adobe structures in Pakistan and Portugal

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    Adobe buildings exist in different parts of the world. The construction of these buildings can be carried out economically, using locally available materials and skills that do not require use of modern machinery. Therefore, adobe buildings provide an economic housing option. The construction of adobe structures is carried out based on traditional construction practices which vary from region to region. This paper presents the results of a study which was conducted to study the construction practices of adobe buildings in Pakistan and Portugal in the context of their seismic vulnerability. The adobe buildings in both these countries were found to be subjected to seismic hazard levels which, although is low in some regions, may cause significant damages. Lack of essential elements or details for the adequate seismic performance was found in the adobe buildings in both regions

    Estimations for the Single Diffractive production of the Higgs boson at the Tevatron and the LHC

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    The single diffractive production of the standard model Higgs boson is computed using the diffractive factorization formalism, taking into account a parametrization for the Pomeron structure function provided by the H1 Collaboration. We compute the cross sections at next-to-leading order accuracy for the gluon fusion process, which includes QCD and electroweak corrections. The gap survival probability () is also introduced to account for the rescattering corrections due to spectator particles present in the interaction, and to this end we compare two different models for the survival factor. The diffractive ratios are predicted for proton-proton collisions at the Tevatron and the LHC for the Higgs boson mass of MHM_H = 120 GeV. Therefore, our results provide updated estimations for the diffractive ratios of the single diffractive production of the Higgs boson in the Tevatron and LHC kinematical regimes.Comment: 20 pages, 6 figures, 3 table

    Mechanism of Reconnection on Kinetic Scales Based on Magnetospheric Multiscale Mission Observations

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    We examine the role that ions and electrons play in reconnection using observations from the Magnetospheric Multiscale (MMS) mission on kinetic ion and electron scales, which are much shorter than magnetohydrodynamic scales. This study reports observations with unprecedented high resolution that MMS provides for magnetic eld (7.8 ms) and plasma (30 ms for electrons and 150 ms for ions). We analyze and compare approaches to the magnetopause in 2016 November, to the electron diffusion region in the magnetotail in 2017 July followed by a current sheet crossing in 2018 July. Besides magnetic eld reversals, changes in the direction of the ow velocity, and ion and electron heating, MMS observed large uctuations in the electron ow speeds in the magnetotail. As expected from numerical simulations, we have veried that when the eld lines and plasma become decoupled a large reconnecting electric eld related to the Hall current (110 mV/m) is responsible for fast reconnection in the ion diffusion region. Although inertial accelerating forces remain moderate (12 mV/m), the electric elds resulting from the divergence of the full electron pressure tensor provide the main contribution to the generalized Ohms law at the neutral sheet (as large as 200 mV/m). In our view, this illustrates that when ions decouple electron physics dominates. The results obtained on kinetic scales may be useful for better understanding the physical mechanisms governing reconnection processes in various magnetized laboratory and space plasmas

    Qualidade e diferenciação em torno do café: modelos em concorrência.

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    O objetivo deste trabalho consiste em discutir dois enfoques divergentes em torno da cafeicultura com vistas a fornecer elementos de análise para uma pesquisa acerca das dinâmicas territoriais, agricultura e sociedade. Cada vez mais, oportunidades se desenham para uma revalorização da cafeicultura, particularmente em sintonia com as idéias de fortalecer a agricultura familiar, de promover as dinâmicas territoriais e de preservar o meio ambiente. Porém, estas oportunidades concorrem com um modelo dominante de conceber os sistemas agro-alimentares no Brasil, no qual a agricultura consiste apenas em suporte para a produção de commodities indiferenciadas, baratas e abundantes

    Dynamics of a Generalized Cosmological Scalar-Tensor Theory

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    A generalized scalar-tensor theory is investigated whose cosmological term depends on both a scalar field and its time derivative. A correspondence with solutions of five-dimensional Space-Time-Matter theory is noted. Analytic solutions are found for the scale factor, scalar field and cosmological term. Models with free parameters of order unity are consistent with recent observational data and could be relevant to both the dark-matter and cosmological-"constant" problems.Comment: 13 page

    Metodologia para determinação da peroxidase e da polifenol oxidase em plantas.

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    Identificação de dinâmicas sociais e econômicas na construção territorial de cafés de qualidade diferenciada no Sul de Minas.

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    O Sul de Minas é a maior região produtora de café do país e o espaço geográfico de Machado, Poço Fundo e Campestre, aí localizado, compreende um dos mais destacados conjuntos de municípios sob o ponto de vista do cultivo. A base técnica e social sob a qual a cultura do café destas três áreas se desenvolveu historicamente é caracterizada por numerosas e pequenas explorações familiares. O café é de toda evidência responsável por uma identidade territorial aí existente, o que torna pertinente uma pesquisa nestes municípios do Sul de Minas Gerais, com ênfase nos conhecimentos, práticas e representações utilizadas na produção, usos, difusão e conservação de recursos do território. O objetivo da pesquisa é buscar respostas aos problemas do desenvolvimento territorial sustentável e, para tal, destacou inicialmente o município de Poço Fundo, dentre os três mencionados. A partir da conclusão do mapeamento de projetos coletivos, atores sociais e programas públicos, esta fase da pesquisa, aqui em destaque, buscou identificar as dinâmicas sociais e econômicas capazes de caracterizar o processo de construção de território junto a gestores públicos e atores representativos dos projetos coletivos, por intermédio do uso de entrevistas apoiadas em um roteiro único semi-estruturado

    Coasting cosmologies with time dependent cosmological constant

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    The effect of a time dependent cosmological constant is considered in a family of scalar tensor theories. Friedmann-Robertson-Walker cosmological models for vacumm and perfect fluid matter are found. They have a linear expansion factor, the so called coasting cosmology, the gravitational "constant" decreace inversely with time; this model satisfy the Dirac hipotesis. The cosmological "constant" decreace inversely with the square of time, therefore we can have a very small value for it at present time.Comment: 7 pages, latex file (ijmpal macro), accepted for publication in Int. Mod. Phys.

    Estudo de retenção de carotenoides totais em híbridos de mandioca cozida.

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    O consumo culinário das raízes de mandioca é bastante generalizado em todo o mundo, sendo que a forma de processamento mais utilizada na América Latina e África é o cozimento. As raízes de mandioca ainda podem ser integradas a pratos mais complexos. O melhoramento e a seleção de matérias primas de origem vegetal com altos conteúdos de micronutrientes vêm sendo realizada nos países em desenvolvimento com a finalidade de minimizar carências nutricionais
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