773 resultados para Cia. do Quintal - Companhia teatral


Relevância:

10.00% 10.00%

Publicador:

Resumo:

模态图是谓词μ演算的一种有效的图形表示形式。证明了谓词μ演算和模态图的语义一致性,详细讨论了谓词μ演算公式、嵌套谓词等式系和模态图之间的关系,并给出了一种优化的从线性公式到嵌套谓词等式系的转换算法。

Relevância:

10.00% 10.00%

Publicador:

Resumo:

National Natural Science Foundation of China; Public Administration and Civil Service Bureau of Macau SAR; Companhia de Telecomunicacoes de Macau S.A.R.L.; Macau SAR Government Tourist Office

Relevância:

10.00% 10.00%

Publicador:

Resumo:

National Natural Science Foundation of China; Public Administration and Civil Service Bureau of Macau SAR; Companhia de Telecomunicacoes de Macau S.A.R.L.; Macau SAR Government Tourist Office

Relevância:

10.00% 10.00%

Publicador:

Resumo:

National Natural Science Foundation of China; Public Administration and Civil Service Bureau of Macau SAR; Companhia de Telecomunicacoes de Macau S.A.R.L.; Macau SAR Government Tourist Office

Relevância:

10.00% 10.00%

Publicador:

Resumo:

National Natural Science Foundation of China; Public Administration and Civil Service Bureau of Macau SAR; Companhia de Telecomunicacoes de Macau S.A.R.L.; Macau SAR Government Tourist Office

Relevância:

10.00% 10.00%

Publicador:

Resumo:

提出了一个用于描述异步π-演算中移动进程的时态和空间性质的模态逻辑.该逻辑具有基于谓词变量的递归构造.建立了这一逻辑的语义理论,并证明了语义的单调性,从而保证了不动点的存在.还设计了一个算法来自动地检测移动进程是否具有用该逻辑公式所描述的性质,并证明了该算法的正确性.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

National Natural Science Foundation of China; Public Administration and Civil Service Bureau of Macau SAR; Companhia de Telecomunicacoes de Macau S.A.R.L.; Macau SAR Government Tourist Office

Relevância:

10.00% 10.00%

Publicador:

Resumo:

National Natural Science Foundation of China; Public Administration and Civil Service Bureau of Macau SAR; Companhia de Telecomunicacoes de Macau S.A.R.L.; Macau SAR Government Tourist Office

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Investigating the interplay between continental weathering and erosion, climate, and atmospheric CO2 concentrations is significant in understanding the mechanisms that force the Cenozoic global cooling and predicting the future climatic and environmental response to increasing temperature and CO2 levels. The Miocene represents an ideal test case as it encompasses two distinct extreme climate periods, the Miocene Climatic Optimum (MCO) with the warmest time since 35 Ma in Earth's history and the transition to the Late Cenozoic icehouse mode with the establishment of the east Antarctic ice sheet. However the precise role of continental weathering during this period of major climate change is poorly understood. Here we show changes in the rates of Miocene continental chemical weathering and physical erosion, which we tracked using the chemical index of alteration ( CIA) and mass accumulation rate ( MAR) respectively from Ocean Drilling Program (ODP) Site 1146 and 1148 in the South China Sea. We found significantly increased CIA values and terrigenous MARs during the MCO (ca. 17-15 Ma) compared to earlier and later periods suggests extreme continental weathering and erosion at that time. Similar high rates were revealed in the early-middle Miocene of Asia, the European Alps, and offshore Angola. This suggests that rapid sedimentation during the MCO was a global erosion event triggered by climate rather than regional tectonic activity. The close coherence of our records with high temperature, strong precipitation, increased burial of organic carbon and elevated atmospheric CO2 concentration during the MCO argues for long-term, close coupling between continental silicate weathering, erosion, climate and atmospheric CO2 during the Miocene. Citation: Wan, S., W. M. Kurschner, P. D. Clift, A. Li, and T. Li (2009), Extreme weathering/ erosion during the Miocene Climatic Optimum: Evidence from sediment record in the South China Sea, Geophys. Res. Lett., 36, L19706, doi: 10.1029/2009GL040279.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The Late Pliocene is thought to be characterized by the simultaneous intensification of both the East Asian winter monsoon (EAWM) and East Asian summer monsoon (EASM). However, the evolution of the EASM during the Pliocene remains still controversial and only little is known about the dynamics of the EASM during the Pliocene on orbital time scales. Here we use clay mineral assemblages in sediments from Ocean Drilling Program (ODP) Site 1143 in the southern South China Sea (SCS) to obtain proxy records of past changes in the EASM climate during the Pliocene. Provenance analysis suggests that illite, chlorite and kaolinite originated mainly from the Mekong River drainage area. Smectite was derived mainly from the Indonesian islands. The kaolinite/illite ratio and the chemical index of alteration (CIA) of siliciclastic sediments allowed us to reconstruct the history of chemical weathering and physical erosion of the Mekong River drainage area and thus, the evolution of,the EASM during the Pliocene. Our clay minerals proxy data suggests a stronger EASM during the Early Pliocene than during the Late Pliocene. We propose that the long-term evolution of the EASM has been driven by global cooling rather than the uplift of the Tibetan Plateau. Spectral analysis of kaolinite/ illite ratio displays a set of strong periodicities at 100 ka, 30 ka, 28 ka, 25 ka, and 22 ka. with no clear obliquityrelated signal. Our study suggests that the Pliocene EASM intensity on orbital time scales is not only controlled by the Northern Hemisphere summer insolation, but also strongly influenced by equatorial Pacific ENSO-like ocean atmosphere dynamics. (C) 2010 Elsevier B.V. All rights reserved.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

AMS(14)C dating and analysis of grain size, major elements and clay minerals were applied to Core MZ01 from the mud area on the inner shelf of the East China Sea. Based on the environmentally sensitive grain size, clay mineral and major element assemblages, the history of the East Asia winter monsoon since the mid-Holocene could be reconstructed. These three proxies, mean grain size (>9.71 mu m), chemical index of alteration (CIA) and ratio of smectite to kaolinite in particular, show similar fluctuation patterns. Furthermore, 10 extreme values corresponding to the contemporary cooling events could be recognized since the mid-Holocene; these extreme values are likely to have been caused by the strengthening of the East Asia winter monsoon. The cooling events correlated well with the results of the delta O-18 curves of the Dunde ice core and GISP2, which therefore revealed a regional response to global climate change. Four stages of the East Asia winter monsoon were identified, i.e. 8300-6300 a BP, strong and unstable; 6300-3800 a BP, strong but stable; 3800-1400 a BP, weak and unstable; after 1400 a BP, weak but stable.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

目的 了解塞隆骨水提物(SLG—B)对胶原诱导的小鼠关节炎的治疗作用及治疗机制。方法 利用牛Ⅱ型胶原诱导DBA/1小鼠类风湿性关节炎模型即CIASLG—B口服给药观察小鼠关节炎指数的变化情况,体外培养关节炎小鼠脾细胞及巨噬细胞,ELISA法测定IL-12、IL-2、IFN-γ TNF-α几种细胞因子。RT-PCR测定SLG-B对关节炎小鼠巨噬细胞IL-1β、IL-6、iNOS mRNA表达的影响。结果 SLG-B能明显的抑制牛Ⅱ型胶原诱导关节炎的发生,能够减轻关节炎的各种症状。SLG-B在加抗原和不加抗原的情况下都能够明显的抑制关节炎小鼠脾细胞的增殖同时发现SLG-B能够抑制IL-2、IFN-1、L-12p40、TNF-α细胞因子的产生。还能够抑制小鼠腹腔巨噬细胞IL-1、IL-6及iNOS mRNA的表达。这可能是SLG—B在小鼠关节炎中表现治疗效果的分子基础。结论 SLG—B对小鼠关节炎有很好的治疗效果,其作用机制主要是通过抑制巨噬细胞及脾细胞产生炎性细胞因子和抑制炎性细胞因子mRNA的表达来达到治疗类风湿性关节炎的作用。

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Late Cenozoic has witnessed a series of climate-environmental change which ends with a transitional shift from greenhouse to icehouse conditions. In last two decades, scientists began to employ the tectonic uplift and its weathering effect to interpret the climatic changes during the late Cenozoic. However, this endeavor has partly been restricted by the lacking of regional and global chemical weathering data. The loess-red clay deposit in the Loess Plateau may record the weathering features of the detritus material from the wide range upwind of the Loess Plateau. Therefore geochemistry of the loess-plaeosol and red clay sequences may provide insights into the regional chemical weathering regime and the connection between the chemical weathering and the late Cenozoic climate-environmental change Here we selected 319 samples from the Baishui section near the Pingliang City, Gansu Province, and analyzed them with X-ray fluorescence. Based on the result, we reconstruct the chemical weathering history of the Baishui section since 6Ma. We chose CIA as the proxy for chemical weathering intensity. The CIA ratio in soil units is higher than in adjacent loess horizons, but lower than in the red clay, in good agreement with the field observation. The CIA ratios of the Baishui section correlates well with the global ice volume fluctuations, indicating that the global cooling may contribute a lot to the chemical weathering variations in Chinese Loess Plateau. There are at least 3 million-year time scale variations that can be identified in the chemical weathering intensity curve, i.e., between 3.3 to 2.1 Ma, 1.7 to 0.9 Ma and from 0.9Ma. We think these may reflect the combined effect of the tectonic uplift and ice sheets on monsoon intensity. Other time scale variations can be also observed. In the period between 2.4 and 0.8 Ma, the CIA record display the 400,000 years cycle, which may be resulted from the Tibetan uplift during the Pliocene-early Pleistocene which have significantly amplified the monsoon response sensitivity to the orbital-scale variations in insolation. From 1.2 Ma, the 100,000 years period became intensifying, and particularly after 0.8 Ma, the earlier monsoon response at 400,000 year periodicity was overwhelmed by the ice sheet forcing at 100,000 year periodicity. These may indicate that the expansions of the Northern Hemisphere ice sheets may have crossed a threshold, which enforce the monsoon responding at the 100,000 year periodicity.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The black rock series of the Upper Ordovician - Lower Silurian in Yangtze area are important source rocks and have exceptional characteristics of sediment, biology, element geochemistry, carbon and oxygen isotope, organic geochemistry and etc. These characteristics are the reflection of important geology events. Due to scarce system research, many problems that relate to the development mechanism of source rocks are not solved. And this restricts the exploration of Oil and gas in South China. In this paper, author studied the palaeo-climate, palaeo-structure and palaeo-environment of the Upper Ordovician - Lower Silurian in Yangtze area by sedimentology, palaeobiology and geochemistry, especially the element geochemistry and isotope geochemistry. The environment model of source rocks is established and some conclusions are drawn. The Upper Ordovician - Lower Silurian sediment types in Yangtze area are mostly black shales, next, mudstone, shell limestone and siltystone. During the Late Ordovician and Earily Silurian periods, a series of big upheaval and depressed are distributed in Yangtze area, and the strata pattern of interphase upheaval and depressed led to Yangtze palaeosea isolated with outside sea. So the stagnant and anoxic environment that are the favorable factor of rich organic black shales sediment is formed in Yangtze area. That Chemical Index of Alteration (CIA) values of the lower Wufeng formation and Longmaxi formation exhibits moderate chemistry weathering suggests they were deposited under the circumstances of the warm and humid climate. However, the large difference of the CIA values of N.extraordinarius-N.ojsuensis biozone suggests that climate is changeful. Therefore, there were two different kinds of climates in the course of the deposition of the Wufeng formation and Longmaxi formation. During the Late Ordovician - Earily Silurian periods, in Yangtze palaeosea, the surface water which is full of rich nutriment and abundant bacterium - algae has high palaeo-productivity that is obvious difference in the different space – time. The content of sulphate changes gradually from the surface water columns to the deep water columns. That is, salinity in the surface water columns is serious low and the salinity in deep water columns is normal. Salinity delamination is favor of the forming of deep anoxic environment. During Wufeng period, the oxidated and low sulfate environment exists in the upper Yangtze palaeosea, while the anoxic and normal salinity environment occurs in the lower Yangtze palaeosea. During the Late Wufeng and Guanyinqiao periods, the steady anoxic environment is replaced by oxidated environment. During the Longmaxi period, layered and anoxic environment recur. In Yangtze area, studies of δ13C of sedimentary organic carbon show a positive δ13C excursion up to 4‰ in the Guanyinqiao stage and then, acute negative excursion in the earily Longmaxi stage. These organic carbon isotopes curve are not only efficient measure of carving up strata borderline, but also reflected the change of originality productivity. These organic carbon isotopes curves showed the process of the enhanced embedding of the global organic carbon. Anoxic event is the main factor of increasing organic carbon embedding speed. And the reduced organic carbon embedding in Hirnantian stage is due to the water column with abundant oxygen. The δ34S values are gradually positive excursion from P.pacificus biozone to N.extraordinarius biozone, and reach the maximum in the Upper Hirnantian stage. Then, the δ34S values are negative excursion. The excursions of δ13C and δ34S reflect the acute change of environment. The formation of source rocks is largely dependent on the nature of organisms from which kerogen is derived and the preservation conditions of organic matter, which are fundamentally dependent on a favourable combination of various elements in which organisms live and are subsequently buried. These elements include palaeoclimate, palaeostructure and palaeoenvironmental conditions. Based on above mentioned circumstance, the coupling connection of source rock and the palaeoclimate, and of palaeostructure and palaeoenvironmental conditions are confirmed, and the “anoxic-marginal depression-photosynthesis” environemental model is established. It is indicated that anoxic played important role in production of organic matter. The produced organic matter was accumulated in marginal depression of the Yangtze area. The photosynthesis is favor of the high productivity. Source rocks have a good perspective, like that of “hot shale” deposited in North Africa.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The loess-red clay deposit in the Loess Plateau, as large regions mixed in the dust depositional areas, may recorded the chemical weathering features and recycling of the detritus material of the earth’s surface from the wide range upwind of the Loess Plateau. And the loess-red clay sequence is rare information for recovering the continent's weathering history of Late Cenozoic, as it’s clear sense of age. The concentrations of elements in loess-red clay are largely affected by grain size. Therefore, we divided samples of a long loess-red clay section and six spacial sections into three fractions in order to counteracting the effect of particle size on the values of weathering proxies. First, the loess unit L1 and S1 of six sections located at Guyuan, Baishui, Changwu, Yongshou, Yangling and Lantian, Chinese Loess Plateau were sampled. These samples were divided into three fractions: <5μm, 5-20μm, 20-63μm, which were then analyzed for the primary elements using an X-ray fluorescence analyser. Results show that the effect of particle is much smaller on the fraction <5μm than other fractions. Therefore, the fraction <5μm can reflect the change of chemical weathering intensity much better. In addition, we divided Baishui section samples into three fractions, and analyzed them with X-ray fluorescence for primary elements. Results show that the value of CIA vary in different size fractions, indicating different weathering progress. Elements K, Na, Ca and Mg in the <5μm fraction have a sequence which is the reverse of Bowen Sequence. This may be a important sense for the change of source regions.