986 resultados para Rais, Gilles de, 1404-1440.


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Synthesis efforts that identify patterns of ecosystem response to a suite of warming manipulations can make important contributions to climate change science. However, cross-study comparisons are impeded by the paucity of detailed analyses of how passive warming and other manipulations affect microclimate. Here we document the independent and combined effects of a common passive warming manipulation, open-top chambers (OTCs), and a simulated widespread land use, clipping, on microclimate on the Tibetan Plateau. OTCs consistently elevated growing season averaged mean daily air temperature by 1.0-2.0 degrees C, maximum daily air temperature by 2.1-7.3 degrees C and the diurnal air temperature range by 1.9-6.5 degrees C, with mixed effects on minimum daily air temperature, and mean daily soil temperature and moisture. These OTC effects on microclimate differ from reported effects of a common active warming method, infrared heating, which has more consistent effects on soil than on air temperature. There were significant interannual and intragrowing season differences in OTC effects on microclimate. For example, while OTCs had mixed effects on growing season averaged soil temperatures, OTCs consistently elevated soil temperature by approximately 1.0 degrees C early in the growing season. Nonadditive interactions between OTCs and clipping were also present: OTCs in clipped plots generally elevated air and soil temperatures more than OTCs in nonclipped plots. Moreover, site factors dynamically interacted with microclimate and with the efficacy of the OTC manipulations.These findings highlight the need to understand differential microclimate effects between warming methods, within warming method across ecosystem sites, within warming method crossed with other treatments, and within sites over various timescales. Methods, sites and scales are potential explanatory variables and covariables in climate warming experiments. Consideration of this variability among and between experimental warming studies will lead to greater understanding and better prediction of ecosystem response to anthropogenic climate warming.

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The effects of La3+ on the uptake of trace elements (Se, Co, V, and Tc) in cucumber plants were studied by a radioactive multitracer technique. It was observed that the uptake and distribution of these trace elements in roots, stems, and leaves are different under different La3+, treatments. Furthermore, in the control, the plant accumulates Se-75, Co-56, and V-48 all in the order roots>leaves>stems, whereas Tc-95m was in the order leaves>stems>roots. The accumulations of Se-75 and Tc-95m in plants treated with different La3+ concentration were in the same order as those in the control, but the uptakes percentages of other kinds of element changed differently. The results indicate that lanthanum treatments to a growing cucumber lead to the change of uptake of trace elements, which suggest that a rare earth element is directly or indirectly involved in the ion transport of the plant and affects plant growth by regulating the uptake and distribution of elements that influence the plant cell physiology and biochemistry.

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Phylogenetic relationships of six species of Ochotona were investigated using mitochondrial DNA (mtDNA) restriction-site analysis. The phylogenetic tree constructed using PAUP was based on 62 phylogenetically informative sites with O. erythrotis designated as an outgroup. Two clades were evident. One contained O. curzoniae, O. huangensis, and O. thibetana. in the second, O. daurica was a sister taxon of O. cansus. The five species appear to come from different maternal lineages. The branching structure of the tree and sequence divergence confirm that huangensis and cansus are distinct species, and that mol-osa is a synonym of O. cansus rather than O. thibetana. Divergence time, estimated from genetic distances, indicates that the ancestors of the two maternal lineages diverged ca. 6.5 x 10(6) years ago. O. curzoniae diverged from O. huangensis, and O. daurica diverged from O. cansus, at about the same time (ca. 3.4 x 10(6) years ago). These data suggest a period of rapid radiation of the genus Ochotona in China, perhaps during the late Pliocene. These calculations correspond roughly to tectonic events and environmental changes in China throughout this period, and appear to be substantiated by the fossil record.

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Granulites from Huangtuling in the North Dabie metamorphic core complex in eastern China preserve rare mineralogical and mineral chemical evidence for multistage metamorphism related to Paleoproterozoic metamorphic processes, Triassic continental subduction-collision and Cretaceous collapse of the Dabieshan Orogen. Six stages of metamorphism are established, based on detailed mineralogical and petrological studies: (I) amphibolite facies (6.3–7.0 kbar, 520–550 °C); (II) high-pressure/high-temperature granulite facies (12–15.5 kbar, 920–980 °C); (III) cooling and decompression (4.8–6.0 kbar, 630-700 °C); (IV) medium-pressure granulite facies (7.7–9.0 kbar, 690–790 °C); (V) low-pressure/high-temperature granulite facies (4.0–4.7 kbar, 860–920 °C); (VI) retrograde greenschist facies overprint (1–2 kbar, 340–370 °C). The P–T history derived in this study and existing geochronological data indicate that the Huangtuling granulite records two cycles of orogenic crustal thickening events. The earlier three stages of metamorphism define a clockwise P–T path, implying crustal thickening and thinning events, possibly related to the assembly and breakup of the Columbia Supercontinent ca. 2000 Ma. Stage IV metamorphism indicates another crustal thickening event, which is attributed to the Triassic subduction/collision between the Yangtze and Sino–Korean Cratons. The dry lower crustal granulite persisted metastable during the Triassic subduction/collision due to lack of hydrous fluid and deformation. Stage V metamorphism records the Cretaceous collapse of the Dabieshan Orogen,possibly due to asthenosphere upwelling or removal of the lithospheric mantle resulting in heating of the granulite and partial melting of the North Dabie metamorphic core complex. Comparison of the Huangtuling granulite in North Dabie and the high-pressure (HP)–ultrahigh-pressure (UHP) metamorphic rocks in South Dabie indicates that the subducted upper (South Dabie) and lower (North Dabie) continental crusts underwent contrasting tectonometamorphic evolution during continental subduction–collision and orogenic collapse. High-pressure granulites are generally characterized by the absence of orthopyroxene. However, the Huangtuling felsic granulite rarely preserves the high-pressure granulite facies assemblage of garnet + orthopyroxene + biotite + plagioclase + K-feldspar + quartz. To investigate the effects of bulk rock composition on the stability of orthopyroxene-bearing, high-pressure granulite facies assemblages in the NCKFMASHTO (Na2O–CaO–K2O–FeO–MgO–Al2O3–SiO2–H2O–TiO2–Fe2O3) system, we constructed a series of P–T–X pseudosections based on the melt-reintegrated composition of the Huangtuling felsic high-pressure granulite. Our calculations demonstrate that the orthopyroxene-bearing, high-pressure granulite facies assemblages are restricted to low XAl [Al2O3/(Na2O + CaO + K2O + FeO + MgO + Al2O3) < 0.35, mole proportion] or high XMg [MgO/(MgO + FeO) > 0.85] felsic–metapelitic rock types. Our study also reveals that the XAl values in the residual felsic–metapelitic, high-pressure granulites could be significantly reduced by a high proportion of melt loss. We suggest that orthopyroxene-bearing high-pressure granulites occur in residual overthickened crustal basement under continental subduction–collision zones and arc–continent collision belts.

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Our study deals with the high resolution body wave tomography in North china and adjacent areas(30°N-43°N,100°E-130°E), where earthquakes occurred many times in history and has a very complicated geological structure. 6870 events recorded at 273 digital seismic stations from CDSN during 1996-2002 and stations settled by Seislab of IGCAS in Bohai Bay area, including 1382 local earthquakes and 5488 teleseismic earthquakes are used in this study. In the data we used, the average number of received stations is greater than 5, the error of picking up direct arrival time is 0.1-0.5s. Before the inversion, we use Checkerboard method to confirm the reliability of result of Local events; use Restoring Resolution Test to confirm the reliability of result of teleseismic events. We also analyzed the effect of different parameters in the inversion. Based the analysis above, the model used in this paper is divided into small blocks with a dimension of 0.33°in the latitude and longitude directions and 5km、15km、30km in depth, and initial velocity model. Using pseudobending method to calculate the ray traveling path, LSQR algorithm to inverse, finally, we got the body velocity images below 25km and above 480km in this area using Joint- inversion with local events and teleseismic events. We made the conclusion at last: (1)at top zone of the south of Sichuan Basin , there exits low velocity anomalies, below 40km is the high velocity zone extend to 300km; (2) Above the 40km of Ordos block exits low velocity zone, while below 40km until 240km, the high velocity anomalies are interlaced by low velocity anomalies. Below 300km, the anomalies are unclear any more; (3) On the whole, the velocity structure below 400km on the mantle transition zone of Eastern China area shows its changes from low velocity to high velocity.

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老厂矿床位于三江成矿带南段昌宁—孟连裂谷的次级澜沧断陷盆地中,昌宁—孟连裂谷是三江成矿带南段的重要成矿段之一,其大地构造位于保山―掸邦微陆块东缘,兰坪—思茅盆地、临沧地块西缘,属东特提斯构造域,是冈瓦纳古陆与欧亚大陆巨型缝合带的组成部分。 矿床开采历史悠久,始于明朝永乐二年(1404年),至今已605年。古时炼银弃铅,最高年产白银30万两。解放后主要开采古人废弃的高铅炉渣,并对深部原生矿体进行了初步勘探,90年代至今对深部银铅矿体进行了详细勘查,深部矿体是矿床主要的开采对象。它以独特的成矿地质特征、富银(铅锌矿石中平均含量为629×10-6,方铅矿中平均2069×10-6)、伴生元素多(In、Se、Te、Ga、Cd、Bi)、规模大(In、Se、Te、Cd已达大型规模)、含Sn等特征而受到广大地质工作者的关注。它是“三江”成矿带南段最具代表性的铅银矿床类型之一,也是昌宁—孟连裂谷内目前探明的唯一大型银铅锌多金属矿床,具有十分重要的研究价值。 虽然前人已从矿床地质、成矿条件、控矿因素等方面对老厂大型银铅锌多金属矿床进行过研究,但研究工作较为零散,在成矿物质与成矿流体来源、矿床成因、花岗斑岩与成矿等方面还存在较大争议。本文在深入细致的野外地质工作基础上,利用多种现代分析测试技术,对矿床进行了较为系统的矿物学、岩石学、年代学和矿床地球化学研究,进而查明了矿床成矿物质与成矿流体来源、揭示了成矿地球动力学背景、探讨了矿床的成因、初步建立了矿床成因模式。论文取得的主要成果如下: 1.查明了硫化物的物质组分及形成阶段。闪锌矿以高铁(早期平均11.51%,晚期平均8.41%)为基本特征,并伴生多种特征的微量元素,早期闪锌矿是Fe、In的主要载体,Cu、Cd、Mn则主要富集在晚阶段闪锌矿中;方铅矿是Ag的主要载体,其早期富Ag、Te、Bi,含Se、Cu,中期主要富Ag,晚期以含As、Bi为特征;其它硫化物成分较单一。 2.揭示了伴生元素赋存状态和富集规律。矿床伴生元素含量高,闪锌矿中Cd平均4293.19×10-6,In平均555.37×10-6,方铅矿中Te平均143.81×10-6,As、Se、Bi、Ga含量也很高。初步估算金属储(万吨)量分别为: Ga 0.097,Cd1.84, In0.13,Se0.06 ,Te0.15,Bi1.28,As4.31。闪锌矿是Ga、In、Cd主要载体,Te、Bi主要赋存在方铅矿中,Se则主要在铅锌、黄铁矿石中富集。 3.首次获得了精确的成矿年代学数据。单颗粒闪锌矿—黄铁矿Rb-Sr法获得矿床成矿年龄t=(45±3.6)Ma,(87Sr/86Sr)i=0.70977±0.00034。证实了矿床成矿与隐伏花岗斑岩关系密切,矿床形成是三江成矿带南段对喜马拉雅碰撞造山成矿运动的响应。 4.首次系统研究了花岗斑岩的地质、地球化学特征。矿床花岗斑岩具高硅、超钾、富碱、贫钠和低镁、钙、铁、磷的特征,岩石为过铝质岩石;其轻稀土富集、Eu为弱负异常、基本无Ce异常、岩石富集大离子亲石元素,具有较高的锶初始值和较低εNd及高的Nd模式年龄,与三江地区富碱斑岩具有相似的地球化学特征。岩浆主要来源于加厚下地壳重熔,成岩过程中有地幔物质的加入,为同碰撞构造环境下形成。 5.首次探讨了容矿沉积建造及矿石、矿物的地球化学特征。矿床碳酸盐岩轻稀土富集、Eu正异常及Ce异常和其微量元素特征与热水沉积岩石相似,表明了碳酸盐岩的热水沉积成因,同时矿石及其硫化物微量和稀土元素特征也指示了在早石炭世矿区发生了广泛的火山喷流热水沉积成矿作用。 6.查明了成矿物质及成矿流体来源。成矿元素研究显示矿床成矿物质具有多来源的特征,Pb同位素研究表明矿床Pb可能来自不同地层岩石的淋滤, S同位素组成显示其可能主要来源于海水对下伏火山岩地层的淋滤与海水硫酸盐的还原,花岗斑岩岩浆也可能提供了部分S。C-O、H-O同位素和矿石及其硫化物稀土元素反映矿床早期成矿流体主要源于深部岩浆,晚期主要来源于喜山期花岗斑岩岩浆热液。 7.初步建立了成矿模式。老厂矿床是长期以来多种地质作用下的综合产物,具有成矿物质多来源,成矿阶段多期次特点。经历了早石炭世火山喷流热水沉积成矿和喜山期花岗斑岩岩浆热液叠加改造成矿作用,热水成矿作用下形成了以黄铁矿为主的块状硫化物矿床,喜山期富碱花岗斑岩岩浆热液流体携带了大量的Cu、Mo、Ag、Pb等成矿元素,在它的叠加改造作用下形成了老厂银多金属矿床。总之矿床为火山喷流沉积—岩浆热液叠加改造成因。

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Este documento sintetiza as informações geradas nas duas últimas décadas por várias Instituições de Pesquisa, Desenvolvimento e Ensino do Brasil, no que se refere a elaboração de um diagnóstico do quadro natural e agrossocioeconômico deste tão importante ecossistema.

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Wood, Ian; Geissert, M.; Heck, H.; Hieber, M., (2005) 'The Ornstein-Uhlenbeck semigroup in exterior domains', Archiv der Mathematik 86 pp.554-562 RAE2008

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Brian Garrod, Roz Wornell and Ray Youell (2006). Re-conceptualising rural resources as countryside capital: The case of rural tourism. Journal of Rural Studies, 22 (1), 117-128. RAE2008

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In this work, we investigate tennis stroke recognition using a single inertial measuring unit attached to a player’s forearm during a competitive match. This paper evaluates the best approach for stroke detection using either accelerometers, gyroscopes or magnetometers, which are embedded into the inertial measuring unit. This work concludes what is the optimal training data set for stroke classification and proves that classifiers can perform well when tested on players who were not used to train the classifier. This work provides a significant step forward for our overall goal, which is to develop next generation sports coaching tools using both inertial and visual sensors in an instrumented indoor sporting environment.

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The tris[tetrachlorobenzenediolato]phosphate(v) anion (TRISPHAT) is known to be an efficient NMR chiral shift agent for various chiral cationic species. Here we compare the efficiency of TRISPHAT and of a chiral lanthanide shift reagent for the determination of the enantiomeric purity of the chiral building block [Ru(phen)[2]PY[2]][2][+] which possesses C[2] symmetry. We also discuss our results in terms of the geometry of interaction between the Ru(II) complex and the TRISPHAT anion.