701 resultados para Monsoy 8757


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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Durante o processo de envelhecimento, as sementes sofrem alterações degenerativas que influenciam o seu potencial fisiológico. Entre estas alterações podem estar as modificações anatômicas nas camadas celulares da testa da semente. Objetivou-se, com este trabalho, verificar a relação entre a anatomia da testa de sementes de soja, cultivar Monsoy 8400 e a germinação, após o envelhecimento acelerado, pelo fato da testa apresentar um papel fundamental na conservação do potencial fisiológico das sementes. As sementes foram envelhecidas a 42ºC e 100% UR do ar por períodos de zero, 24, 48, 72 e 96 horas. Avaliaram-se os teores de água e a germinação, posteriormente à secagem, seções transversais da testa de 10 sementes de cada tratamento foram eletromicrografadas, com microscópio eletrônico de varredura,,observando-se as camadas das células paliçádicas, ampulhetas e parenquimáticas A germinação declinou com o aumento dos períodos de envelhecimento. Houve redução da espessura das camadas da testa nos períodos de 48, 72 e 96 horas deste processo. Observou-se que, principalmente, para os períodos de envelhecimento de 72 e 96 horas, que as células da camada hipodérmica apresentaram um aspecto de colapso, sendo este acentuado para o período de 96 horas. A redução da espessura das camadas sugere a ocorrência de um colapso das células que compõem tais camadas, sendo um fator causador da redução do potencial germinativo.

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We extend Aumann's [3] theorem deriving correlated equilibria as a consequence of common priors and common knowledge of rationality by explicitly allowing for non-rational behavior. We replace the assumption of common knowledge of rationality with a substantially weaker notion, joint p-belief of rationality, where agents believe the other agents are rational with probabilities p = (pi)i2I or more. We show that behavior in this case constitutes a constrained correlated equilibrium of a doubled game satisfying certain p-belief constraints and characterize the topological structure of the resulting set of p-rational outcomes. We establish continuity in the parameters p and show that, for p su ciently close to one, the p-rational outcomes are close to the correlated equilibria and, with high probability, supported on strategies that survive the iterated elimination of strictly dominated strategies. Finally, we extend Aumann and Dreze's [4] theorem on rational expectations of interim types to the broader p-rational belief systems, and also discuss the case of non-common priors.

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浸入边界法(Immersed Boundary Method)是计算流体力学中求解具有复杂、移动边界流动问题的一类有效途径,该方法在笛卡尔坐标系上离散求解流体控制方程,并通过在控制方程中添加相应源相来代表浸入边界。尽管浸入边界法借助其简单、高效的显著特点在计算流体力学应用中显示出极强的生命力,特别是针对复杂的实际流动及动边界流动问题有着无可比拟的优势,但仍有许多问题需要进一步的研究。 本论文基于浸入边界方法及多矩VSIAM3(Volume/Surface Integrated Average Multi-Moment Method)格式提出了一种不可压缩流体求解数值格式。不可压N-S方程使用VSIAM3格式进行法进行离散,引入浸入边界法处理复杂、移动流动边界条件,使用虚拟网格方法计算动量方程修正项,同时还考虑了对连续方程的修正。VSIAM3格式是一种基于多矩的有限体积法,在方程的离散中总是使用两种或两种以上的矩,如:VIA(Volume Integrated Average)和SIA(Surface Integrated Average)。而不同的矩在求解过程中依据不同形式的控制方程使用不同的离散方法进行更新。VSIAM3格式更多的局地自由度及同时使用交错网格和同位网格的特点使浸入边界法的实施更加便利、高效。研究中,浸入边界法不仅应用于处理动力边界条件,同样可以处理热动力边界条件。 研究中对大量经典算例进行了数值实验,包括一维线性初始问题、方腔流问题、二维绕静止及振荡圆柱流动、三维绕球流动及热对流问题等。数值结果同实验值及其它计算结果保持一致,该算法可准确、高效处理具有复杂、移动边界及存在热对流的不可压流动问题,为实际应用打下了基础。

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When studying physical systems, it is common to make approximations: the contact interaction is linear, the crystal is periodic, the variations occurs slowly, the mass of a particle is constant with velocity, or the position of a particle is exactly known are just a few examples. These approximations help us simplify complex systems to make them more comprehensible while still demonstrating interesting physics. But what happens when these assumptions break down? This question becomes particularly interesting in the materials science community in designing new materials structures with exotic properties In this thesis, we study the mechanical response and dynamics in granular crystals, in which the approximation of linearity and infinite size break down. The system is inherently finite, and contact interaction can be tuned to access different nonlinear regimes. When the assumptions of linearity and perfect periodicity are no longer valid, a host of interesting physical phenomena presents itself. The advantage of using a granular crystal is in its experimental feasibility and its similarity to many other materials systems. This allows us to both leverage past experience in the condensed matter physics and materials science communities while also presenting results with implications beyond the narrower granular physics community. In addition, we bring tools from the nonlinear systems community to study the dynamics in finite lattices, where there are inherently more degrees of freedom. This approach leads to the major contributions of this thesis in broken periodic systems. We demonstrate the first defect mode whose spatial profile can be tuned from highly localized to completely delocalized by simply tuning an external parameter. Using the sensitive dynamics near bifurcation points, we present a completely new approach to modifying the incremental stiffness of a lattice to arbitrary values. We show how using nonlinear defect modes, the incremental stiffness can be tuned to anywhere in the force-displacement relation. Other contributions include demonstrating nonlinear breakdown of mechanical filters as a result of finite size, and the presents of frequency attenuation bands in essentially nonlinear materials. We finish by presenting two new energy harvesting systems based on our experience with instabilities in weakly nonlinear systems.

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Multiyear ichthyoplankton surveys used to monitor larval fish seasonality, abundance, and assemblage structure can provide early indicators of regional ecosystem changes. Numerous ichthyoplankton surveys have been conducted in the northern Gulf of Mexico, but few have had high levels of temporal resolution and sample replication. In this study, ichthyoplankton samples were collected monthly (October 2004–October 2006) at a single station off the coast of Alabama as part of a long-term biological survey. Four seasonal periods were identified from observed and historic water temperatures, including a relatively long (June–October) “summer” period (water temperature >26°C). Fish egg abundance, total larval abundance, and larval taxonomic diversity were significantly related to water temperature (but not salinity), with peaks in the spring, spring–summer, and summer periods, respectively. Larvae collected during the survey represented 58 different families, of which engraulids, sciaenids, carangids, and clupeids were the most prominent. The most abundant taxa collected were unidentified engraulids (50%), sand seatrout (Cynoscion arenarius, 7.5%), Atlantic bumper (Chloroscombrus chrysurus, 5.4%), Atlantic croaker (Micropogonias undulatus, 4.4%), Gulf menhaden (Brevoortia patronus, 3.8%), and unidentified gobiids (3.6%). Larval concentrations for dominant taxa were highly variable between years, but the timing of seasonal occurrence for these taxa was relatively consistent. Documented increases in sea surface temperature on the Alabama shelf may have various implications for larval fish dynamics, as indicated by the presence of tropical larval forms (e.g., fistularids, labrids, scarids, and acanthurids) in our ichthyoplankton collections and in recent juvenile surveys of Alabama and northern Gulf of Mexico seagrass habitats.

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O presente trabalho consiste em analisar as características mais marcantes da tribo urbana Emo, cuja origem se encontra no estilo musical emocore. Trata-se de um estudo que pontua basicamente a música, sexualidade, moda e sentimentalidades no imaginário emo, apresentadas como elementos que se configuram em élans comunitários da tribo. Dentro da perspectiva da Pós-modernidade, a pesquisa não objetiva encontrar razões ou justificativas para o comportamento dos jovens da tribo, apenas ponderar algumas temáticas sob a ótica do imaginário, tribalismo urbano e conceitos de corpo dentro do viés já explorado em pesquisas de Comunicação Social. Tendo a rede social Facebook como principal terreno para realização da netnografia, foram analisadas publicações em perfis e fan pages desmistificando a tribo e mostrando as diversas facetas destes jovens. Ao abordar temas polêmicos como bissexualidade, androginia, suicídio e automutilação, o estudo mostra como os emos se colocam socialmente dentre suas lógicas subversivas e contraditórias elucidando outras formas de ver o mundo. Os conceitos de tribalismo urbano de Maffesoli (1987) guiaram os passos deste estudo que se valeu da ótica deste e de outros autores que tratam questões da Pós-modernidade

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