989 resultados para 174-1074
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目的:探讨采用工程材料力学中抗弯梁的力学模型,通过兔胫骨三点弯测试,获得整骨材料力学测试方法实用的力学参数。方法:采用10只正常成年大耳白兔下肢骨标本,共10对胫骨,行三点弯力学测试。作为骨的三维实体模型建立后,虚拟加载的一种实验对比模式。支承跨距为80mm。结果:得到10对正常大耳白兔胫骨抗弯力学参数。胫骨最大载荷所对应的加载点挠度平均值右侧(2.737±0.262)mm,左侧(2.739±0.233)mm;胫骨的最大载荷(代表抗弯强度)的平均值右侧(17.803±2.675)kg,左侧(18.366±2.653)kg;胫骨最大载荷前载荷-挠度曲线下面积平均值右侧(23.829±4.413)kg·mm,左侧(24.725±4.101)kg·mm;胫骨载荷 ̄挠度曲线线性部分斜率(代表抗弯刚性)平均值右侧(7.545±1.310)kg/mm,左侧(7.631±1.174)kg/mm。结论:正常家兔胫骨个体间差异较大,建议三点弯测试实验中采用双侧配对比较。
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Background: Metabolic syndrome (MS) is a clustering of cardiometabolic risk factors that is considered a predictor of cardiovascular disease, type 2 diabetes and mortality. There is no consistent evidence on whether the MS construct works in the same way in different populations and at different stages in life. Methods: We used confirmatory factor analysis to examine if a single-factor-model including waist circumference, triglycerides/HDL-c, insulin and mean arterial pressure underlies metabolic syndrome from the childhood to adolescence in a 6-years follow-up study in 174 Swedish and 460 Estonian children aged 9 years at baseline. Indeed, we analyze the tracking of a previously validated MS index over this 6-years period. Results: The estimates of goodness-of-fit for the single-factor-model underlying MS were acceptable both in children and adolescents. The construct stability of a new model including the differences from baseline to the end of the follow-up in the components of the proposed model displayed good fit indexes for the change, supporting the hypothesis of a single factor underlying MS component trends. Conclusions: A single-factor-model underlying MS is stable across the puberty in both Estonian and Swedish young people. The MS index tracks acceptably from childhood to adolescence.
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Tracking the evolution of research in waste recycling science (WRS) can be valuable for environmental agencies, as well as for recycling businesses. Maps of science are visual, easily readable representations of the cognitive structure of a branch of science, a particular area of research or the global spectrum of scientific production. They are generally built upon evidence collected from reliable sources of information, such as patent and scientific publication databases. This study uses the methodology developed by Rafols et al. (2010) to make a “double overlay map” of WRS upon a basemap reflecting the cognitive structure of all journal-published science, for the years 2005 and 2010. The analysis has taken into account the cognitive areas where WRS articles are published and the areas from where it takes its intellectual nourishing, paying special attention to the growing trends of the key areas. Interpretation of results lead to the conclusion that extraction of energy from waste will probably be an important research topic in the future, along with developments in general chemistry and chemical engineering oriented to the recovery of valuable materials from waste. Agricultural and material sciences, together with the combined economics, politics and geography field, are areas with which WRS shows a relevant and ever increasing cognitive relationship.
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应用半权函数法求解双材料界面裂纹的应力强度因子,得到以半权函数对参考位移与应力加权积分的形式表示的应力强度因子.针对特征值为复数λ的双材料界面裂纹裂尖应力和位移场,设置与之对应特征值为-λ的位移函数,即半权函数.半权函数的应力函数满足平衡方程,应力应变关系,界面的连续条件以及在裂纹面上面力为0;半权函数与裂纹体的几何尺寸无关,对边界条件没有要求.由功的互等定理得到应力强度因子K_Ⅰ和K_Ⅱ的积分形式表达式.本文计算了多种情况下界面裂纹应力强度因子的算例,与文献结果符合得很好.由于裂尖应力的振荡奇异性已经在积分中避免,只需考虑绕裂尖远场的任意路径上位移和应力,即使采用该路径上较粗糙的参考解也可以得到较精确的结果.
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[EN] Progress in methodology in specific fields is usually very closely linked to the technological progress in other areas of knowledge. This justifies the fact that lexicographical techniques have had to wait for the arrival of the IT era of the last decades of the 20th century in order to be able to create specialised electronic dictionaries which can house and systemise enormous amounts of information which can later be dealt with quickly and efficiently. This study proposes a practical-methodological model which aims to solve the grammatical treatment of adverbs in Ancient Latin. We have suggested a list of 5 types, in a decreasing order from a greater to lesser degree of specialisation; technical (T), semi-technical (S-T), instrumental-valued (I-V), instrumental- descriptive (I-D), instrumental-expository (I-E).
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Anejos de Veleia, Series Minor, 26. Editado por Vitalino Valcárcel.
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Lei n. 9.503, de 23 de setembro de 1997, e legislação correlata.
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La situación del entorno actual, marcado por el efecto de la globalización, conduce a buscar nuevos enfoques organizacionales para ofrecer soluciones prácticas a la creciente dinamización del mercado. Clientes, proveedores, subcontratistas, competidores, centros de investigación, universidades… tienden a interrelacionarse configurando el concepto de “empresa extendida”: red de nodos ágiles, flexibles, con conexiones mundiales y con capacidad de reconfiguración permanente, características vitales para mantenerse competitivo. En este artículo se ha realizado una labor de estudio y análisis de teorías organizacionales consideradas seminales y se ha evaluado su idoneidad en el contexto competitivo actual. El resultado ha sido el diseño de un modelo de gestión basado en un enfoque proactivo que se sustenta en la gestión del conocimiento organizacional y que aboga por valores como el desequilibrio constante, la relación con otras organizaciones buscando efectos sinérgicos y la compartición del saber, entre otros.
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Este artículo se ha realizado en el marco de los Proyectos de Investigación titulados “Los sistemas integrados de gestión (SIG) en las empresas españolas” (SEC2006-06682/ECON) financiado por el Ministerio de Educación y Ciencia dentro de la convocatoria de ayuda a proyectos de I+D y “Análisis de la implantación de los Sistemas de Gestión Medioambiental en las empresas de la CAPV: generación de propuestas innovadoras para su integración organizativa”, financiado por la UPV-EHU en su convocatoria general de Proyectos de Investigación de 2006.
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The migratory population of striped bass (Morone saxatilis) (>400 mm total length[TL]) spends winter in the Atlantic Ocean off the Virginia and North Carolina coasts of the United States. Information on trophic dynamics for these large adults during winter is limited. Feeding habits and prey were described from stomach contents of 1154 striped bass ranging from 373 to 1250 mm TL, collected from trawls during winters of 1994-96, 2000, and 2002-03, and from the recreational fishery during 2005-07. Nineteen prey species were present in the diet. Overall, Atlantic menhaden (Brevoortia tyrannus) and bay anchovy (Anchoa mitchilli) dominated the diet by boimass (67.9%) and numerically (68.6%). The percent biomass of Atlantic menhaden during 1994-2003 to 87.0% during 2005-07. Demersal fish species such as Atlantic croaker (Micropogonias undulatus) and spot (Leiostomus xanthurus) represented <15% of the diet biomass, whereas alosines (Alosa spp.) were rarely observed. Invertebrates were least important, contributing <1.0% by biomass and numerically. Striped bass are capable of feeding on a wide range of prey sizes (2% to 43% of their total length). This study outlines the importance of clupeoid fishes to striped bass winter production and also shows that predation may be exerting pressure on one of their dominant prey, the Atlantic menhaden.
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The communities associated with Mytilus californianus (mussel) beds from 20 geographic sites in southern California were examined. The study areas included six mainland sites - Government Point, Goleta Point, Ventura, Corona del Mar, Carlsbad, and San Diego,and two sites on opposite sides of seven offshore islands - San Miguel Island, Santa Rosa Island, Santa Cruz Island, Anacapa Island, San Nicholas Island, Santa Cruz Island and San Clemente Island. : The mussel communities from all areas contributed to the master species list which now encompasses conservatively, 610 species of animals and 141 species of algae. The most diverse collection came from Cat Rock, Anacapa Island where the mussel beds supported 174 species of invertebrates. The lowest diversity was recorded for mussel beds from Ben Weston, Santa Catalina Island which contained 46 species. In general, the island mussel beds supported a greater diversity of both animals and plants. Mussel community samples were collected from upper and lower intertidal areas occupied by the mussel beds within a locality. Community differences in both composition and abundance were associated with these collections. Overall. community similarity analysis revealed five major patterns which corresponded to characteristic species assemblages occupying the mussel beds from the various geographic areas. The patterns included: (1) clusters of localities which display a north-south geographic pattern with respect to the similarity of their respective mussel communities, (2) a separation of selected island and mainland communities because of dissimilarities in their species composition, (3) differences between mussel communities. on opposite sides of the offshore islands, (4) clusters of species whose highest abundances characterize selected localities, (5) species groups ubiquitous to all mussel beds examined. The results of the community analysis further suggest that predictions can be made delineating the probable mussel community inhabitants of areas not sampled. The species distribution patterns observed appear to correspond in part to the influence of currents and water masses which bear planktonic larvae and impinge on selected localities. The most important mussel bed features associated with community differences were quantitative and qualitative differences in the potential microhabitats. Those features associate~ with greater species diversity include the pore base of coarse fraction shell and rock debris, skewness and kurtosis of the sediment grain-size distributions and mussel bed thickness. Those features associated with lower species diversity included the quantity of tar. and rock and shell debris trapped within the mussel bed. (PDF contains 51 pages)
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A história Bibliográfica de Sertum palmarum brasiliensium... é a seguinte: em 1900, o Deputado Federal por São Paulo, D. Augusto César Miranda Azevedo, apresentou ao Congresso Nacional uma emenda à proposta orçamentária para 1901, autorizando o Poder Executivo "a mandar imprimir na Imprensa Nacional o texto e as estampas da monografia sobre palmeiras do botânico brasileiro Dr. João Barbosa Rodrigues..." Entretanto, a autorização não pôde ser efetivada porque a Imprensa Nacional não dispunha de equipamento para a reprodução de estampas. Em 1901, o Senador pelo Estado do Pará, Dr. Lauro Sodré, apresentou emenda à proposta orçamentária para 1902, cuja lei estabeleceu no art. 6º : "é o Governo autorizado a mandar imprimir na Europa ou em país onde houver mais vantagem, a obra Sertum palmarum..., abrindo para tal fim o necessário crédito, e de acordo com o autor". O crédito -- duzentos contos de réis -- foi finalmente, aberto o Decreto nº 4.428, de 12 de junho de 1902, assinado por Campos Sales e referendado por Sabino Barroso, Ministro da Justiça. A obra foi impressa em Bruxelas sob a direção do próprio Barbosa Rodrigues, que, para esse fim ali se demorou nove meses. Trata-se de trabalho gráfico de primeira ordem, tanto pela reprodução colorida das estampas, como pelo texto e encadernação.