989 resultados para 1748-1809


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Pesquisar sobre escritoras portuguesas do século XIX não é tarefa das mais simples. A barreira maior é a escassez de fontes, que se deve, principalmente, ao papel que cabia à mulher na sociedade de oitocentos. Sem direitos políticos e restrita ao espaço privado, deveria estar sempre sob a dependência de um homem. Ao penetrar num espaço que não era o seu, é compreensível que as mulheres que ousaram se afirmar como escritoras o tenham feito a princípio sob o signo do anonimato. É o caso de Maria Peregrina de Sousa (1809-1894). Teve participação profunda nos periódicos literários da época, nos quais publicou romances, poemas e contos populares, utilizando pseudônimos como Uma obscura portuense, Mariposa ou suas iniciais, D. M. P. Por meio de um diálogo com a História, estudamos as obras Retalho do mundo (1859), Maria Isabel (1866), Henriqueta: romance original (1876) e Pepa (1846), da qual também fizemos a edição. Nosso objetivo é investigar, nesses textos, como o discurso do senso comum ora se confirma às vezes, ora é desestabilizado, e como algumas personagens poderiam contornar os interditos sociais. Ao trazer essa obscura portuense à luz, pretendemos também refletir sobre como uma autora pensava a sua realidade e qual o reflexo disso na sua produção literária.

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O intelectual Thomáz Antônio Gonzaga é aqui tema de uma pesquisa aprofundada, mais ainda no que diz respeito às suas concepções políticas filosóficas e às suas atitudes enquanto vassalo da coroa portuguesa, num esforço de reconstruí-lo para a historiografia, já que, a principio, foi enxergado como um revolucionário nacionalista e como um dos maiores adeptos das ideias ilustradas da América portuguesa. Com um olhar mais apurado em seus escritos, principalmente se estes forem analisados dentro de suas respectivas conjunturas e, por outro lado, sem deixar de se considerar um desenvolvimento intelectual e acadêmico linear, é possível conhecer as bases teóricas utilizadas pelo poeta, bases estas adquiridas durante a sua vida. Tanto da época e que foi aluno em Coimbra (e até mesmo antes, estudou com os jesuítas me Salvador), quanto de suas atuações como ouvidor em Vila Rica. Thomáz Antônio Gonzaga e sua filosofia, portanto, vêm representar justamente a presença de concepções que foram de encontro às ideias revolucionárias, demonstrando o quanto fora hibrido esta época de transformações. Como homem de letras e que obtém sua formação acadêmica em Coimbra para exercer depois cargos oficiais em nome da coroa, é, a principio, representativo de um grupo que envolveu-se com a filosofia iluminista para promover um levante em Minas Gerais. Porém, aprofundando a pesquisa em seus escritos filosóficos, principalmente no que aborda em seu Tratado de Direito Natural, identifica-se um intelectual que possuía uma base teórica muito especifica que pouco tinha haver com a filosofia revolucionária.

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首次报道了云南元谋盆地(虎跳滩土林、湾堡土林和新华土林)晚上新世的硅化木材植物群和山西太谷盆地晚上新世的炭屑木材植物群,分析了这两个盆地当时的植被、环境和气候,为认识我国西南地区和北方中部地区晚上新世气候变化提供了生物学证据。 1。云南元谋盆地晚上新世沙沟组(相当于钱方等1991元谋组下部一、二段)化石木植物群包括:裸子植物1种,归属于三尖杉科(Cephalotaxaceae)三尖杉属(Cephalotaxus)或红豆杉科(Taxaceae)穗花杉属(Amentotaxus);被子植物11种,分别归属于楝科(Meliaceae)香椿属(Toona)、大戟科(Euphorbiaceae)秋枫属(Bischofia)、榆科(Ulmaceae)榉属(Zelkova)、豆科(Fabaceae)黄檀属(Dalbergia)、壳斗科(Fagaceae)锥属(Castanopsis)、青冈属(Cyclobalanopsis)、 千屈菜科(Lythraceae)紫薇属(Lagerstroemia)、桑科(Moraceae)桑属(Morus)、胡桃科(Juglandaceae)、豆科和壳斗科。其中三尖杉属或穗花杉属、楝科香椿属、豆科黄檀属、壳斗科锥属、青冈属、千屈菜科紫薇属、桑科桑属、胡桃科和壳斗科的化石木在我国为首次报道。依据植物群的组成,当时该盆地周围山地上的森林是以锥属、青冈属和三尖杉属或穗花杉属为主要分子的常绿针阔混交林,盆地内的树木包括楝科香椿属、大戟科秋枫属、豆科和千屈菜科紫薇属等植物;当时的气候为亚热带气候,温暖湿润。与印度同时代植物群相比,元谋植物群不具有典型的热带雨林分子如龙脑香科植物,而在印度晚第三纪则常见热带雨林分子。这种差异可能是因为中印植物区系起源不同,以及地质历史时期青藏高原的隆升造成区域气候分异,从而导致中印古植物区系不同。 2.山西太谷盆地晚上新世小白组化石木植物群包括榆科(Ulmaceae)榆属(Ulmus)、蔷薇科(Rosaceae)李属(Prunus)和桑科柘属(Cudrania),它们的标本保存为炭屑木材。该化石木群的发现,以及综合通过孢粉学研究得出的古气候研究结果,表明当时当地属于典型的温带气候。化石木清晰的生长轮表明当时气候具明显的季节性。现代生态木材解剖学研究发现温带干旱地区植物群中导管分子壁的螺纹加厚比例较高、且明显。化石木标本导管分子壁具明显的螺纹加厚也表明盆地内为温带的气候类型。孢粉学研究和地层中丰富的石膏层也表明当时气候具有明显的干湿波动,地层中多层炭屑的存在证明了当时气候条件下森林火频繁发生。这些炭屑木材的发现丰富了太谷盆地晚上新世植物群,为古植被重建和古环境恢复提供了新的证据

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Management agencies often use geopolitical boundaries as proxies for biological boundaries. In Hawaiian waters a single stock is recognized of common bottlenose dolphins, Tursiops truncatus, a species that is found both in open water and near-shore among the main Hawaiian Islands. To assess population structure, we photo-identified 336 distinctive individuals from the main Hawaiian Islands, from 2000 to 2006. Their generally shallow-water distribution, and numerous within-year and between-year resightings within island areas suggest that individuals are resident to the islands, rather than part of an offshore population moving through the area. Comparisons of identifications obtained from Kaua‘i/Ni‘ihau, O‘ahu, the “4-island area,” and the island of Hawai‘i showed no evidence of movements among these island groups, although movements from Kaua‘i to Ni‘ihau and among the “4-islands” were documented. A Bayesian analysis examining the probability of missing movements among island groups, given our sample sizes for different areas, indicates that interisland movement rates are less than 1% per year with 95% probability. Our results suggest the existence of multiple demographically independent populations of island-associated common bottlenose dolphins around the main Hawaiian islands.

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The seismic performance of waterfront cantilever sheet pile retaining walls is of continuing interest to geotechnical engineers as these structures suffer severe damage and even complete failure during earthquakes. This is often precipitated by liquefaction of the surrounding soil, either in the backfill or in front of the wall. This paper presents results from a series of small-scale plane strain models that were tested on a 1-g shaking table and recorded using a high-speed, high-resolution digital camera. The technique of Particle Image Velocimetry (PIV) was applied in order to allow the failure mechanisms to be visualised. It is shown that using PIV analyses it is possible to obtain failure mechanisms for a cantilever wall in liquefiable soil. These failure mechanisms are compared with those obtained for a cantilever wall in dry soil, previously carried out at a similar scale. It was observed that seismic liquefaction causes significant displacement in much larger zones of soil near the retaining wall compared to an equivalent dry case. The failure mechanism for a cantilever wall with liquefiable backfill, but with a remediated zone designed not to liquefy, is also presented and compared to the unremediated case.

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This paper describes four centrifuge tests investigating the performance of non-structural inclined micro-piles as a liquefaction remediation method for existing buildings. Two soil profiles with the same superstructure founded on each were tested under earthquakes of different magnitudes and durations. The first profile consisted of a deep, homogeneous layer of loose, liquefiable sand. The second comprised a shallow layer of loose sand overlying dense sand. Centrifuge tests were carried out with and without inclined micro-piles in each soil profile. The superstructure was modelled as an idealised single degree of freedom (SDOF) system. It is found that the micro-piles have no detrimental effect on the performance of the structure during and after earthquakes. It is also possible that their presence may decrease structural settlements in earthquakes which cause liquefaction to a depth less than that of the improved zone. However, no conclusive evidence is obtained to show that the micro-piles significantly restrain lateral soil movement due to monotonic shearing from the structure or impede the migration of excess pore pressures from the free field to the foundation zone. Both these processes have critical effects on structural settlement. The use of inclined micro-piles for liquefaction remediation should therefore be considered with caution.

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The seismic behaviour of anchored sheet pile walls is a complex soil-structure interaction problem. Damaged sheet pile walls are very expensive to repair and their seismic behaviour needs to be investigated in order to understand their possible mechanisms of failure. The research described in this paper involves both centrifuge testing and Finite Element (FE) analyses aimed at investigating the seismic behaviour of an anchored sheet pile wall in dry sand. The model wall is tied to the backfill with two tie rods connected to an anchor beam. The accelerations of the sheet pile wall, the anchor beam and the soil around the wall were measured using miniature piezoelectric accelerometers. The displacement at the tip of the wall was also measured. Stain gauges at five different locations on the wall were used to measure the bending moments induced in the the wall. The anchor forces in the tie rods were also measured using load cells. The results from the centrifuge tests were compared with 2-D, plane strain FE analyses conducted using DIANA-SWANDYNE II and the observed seismic behaviour was explained in the light of these findings. © 2011 Taylor & Francis.

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本发明提供一种具有止血功能的尖吻蝮蛇毒凝血酶Ⅰ及其生产方法。经阴离子交换剂柱层析法分离纯化和快速蛋白纯化工作站程序再纯化,本发明从我国特产尖吻蝮(Agkistrodon acutus)的蛇毒中得到纯度在97%以上的尖吻蝮蛇毒凝血酶Ⅰ;经测定,该酶Ⅰ由A、B两个亚基(链)组成,其中,A亚基含有135个氨基酸,B亚基含有126个氨基酸。与现有蛇毒凝血酶(如Reptilase)相比,它是一个全新的新型酶止血剂;经药理、毒理、药代等研究表明,本发明的尖吻蝮蛇毒凝血酶Ⅰ是一个见效快、副作用小、安全有效的新型止血剂。

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Ferroic-order parameters are useful as state variables in non-volatile information storage media because they show a hysteretic dependence on their electric or magnetic field. Coupling ferroics with quantum-mechanical tunnelling allows a simple and fast readout of the stored information through the influence of ferroic orders on the tunnel current. For example, data in magnetic random-access memories are stored in the relative alignment of two ferromagnetic electrodes separated by a non-magnetic tunnel barrier, and data readout is accomplished by a tunnel current measurement. However, such devices based on tunnel magnetoresistance typically exhibit OFF/ON ratios of less than 4, and require high powers for write operations (>1 × 10 6 A cm -2). Here, we report non-volatile memories with OFF/ON ratios as high as 100 and write powers as low as ∼1 × 10 4A cm -2 at room temperature by storing data in the electric polarization direction of a ferroelectric tunnel barrier. The junctions show large, stable, reproducible and reliable tunnel electroresistance, with resistance switching occurring at the coercive voltage of ferroelectric switching. These ferroelectric devices emerge as an alternative to other resistive memories, and have the advantage of not being based on voltage-induced migration of matter at the nanoscale, but on a purely electronic mechanism. © 2012 Macmillan Publishers Limited. All rights reserved.

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Computer modelling approaches have significant potential to enable decision-making about various aspects of responsive manufacturing. In order to understand the system prior to the selection of any responsiveness strategy, multiple process segments of organisations need to be modelled. The article presents a novel systematic approach for creating coherent sets of unified enterprise, simulation and other supporting models that collectively facilitate responsiveness. In this approach, enterprise models are used to explicitly define relatively enduring relationships between (i) production planning and control (PPC) processes, that implement a particular strategy and (ii) process-oriented elements of production systems, that are work loaded by the PPC processes. Coherent simulation models, can in part be derived from the enterprise models, so that they computer execute production system behaviours. In this way, time-based performance outcomes can be simulated; so that the impacts of alternative PPC strategies on the planning and controlling historical or forecasted patterns of workflow, through (current and possible future) production system models, can be analysed. The article describes the unified modelling approach conceived and its application in a furniture industry case study small and medium enterprise (SME). Copyright © 2010 Inderscience Enterprises Ltd.

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用原位杂交技术,以地高辛标记的反义RNA为探针,检测了金鱼(Carassiusauratus)DEAD box家族基因vasa在卵子及精子发生中的分布及表达。结果表明在金鱼卵子发生中,在各个时期的卵母细胞的胞质中均有金鱼vasaRNA的杂交信号表达。在Ⅰ、Ⅱ期卵母细胞中vasaRNA的杂交信号强烈,均匀地分布在整个胞质。随着卵母细胞的生长发育及卵黄的积累,Ⅲ、Ⅳ期卵母细胞胞质中vasaRNA的杂交信号急剧减弱,而外周皮层区域,其阳性信号仍较强。在金鱼精子发生中,在精原细胞和初级精母细胞中可检测到金鱼vas