990 resultados para 184-1143
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利用重离子熔合蒸发反应和在束γ谱学实验方法 ,研究了双奇核184 Au的高自旋态能级结构 .扩展了基于πh9/ 2 ν7/ 2 - [5 14 ]和πi13/ 2 νi13/ 2 2准粒子组态下的转动带能级纲图 ,建立了两个转动带之间以及πh9/ 2 ν7/ 2 - [5 14 ]带与基态的谱学连接 .从而确定了πi13/ 2 νi13/ 2 带能级的自旋和宇称 ,证实了此转动带在低自旋区出现旋称反转 .分析了πi13/ 2 νi13/ 2 带和相邻核转动带的准粒子顺排特征 ,指出此带的第一回弯以及相邻核转动带在低频观测到的顺排异常可能与h9/ 2 质子顺排有关 .
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Search for low-spin signature inversion in the pi i(13/2) circle times nu i(13/2) bands in odd-odd Au-182,Au-184,Au-186 has been conducted through the standard in-beam gamma-spectroscopy techniques. The experiments for Au-182 and 186Au have been performed in the Japan Atomic Energy Agency (JAEA) via the Sm-152(Cl-35,5n)Au-182 and Yb-172(F-19,5n)Au-186 reactions, respectively. A study of Au-184 has been made using a multi-detector array GASP in LNL, Italy, via the Tb-159(Si-29,4n)Au-184 reaction. The pi i(13/2) circle times nu i(13/2) bands in these three nuclei have been identified and extended up to high-spin states. In particular, the inter-band connection between the pi i(13/2) nu i(13/2) band and the ground-state band in 184 Au has been established, leading to a firm spin-and-parity assignment for the pi i(13/2) circle times nu i(13/2) band. The low-spin signature inversion is found in the pi i(13/2) circle times nu i(13/2) bands in Au-182,Au-184,Au-186 according to our spin-assignment and the signature crossing observed at high-spin states.
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Search for low-spin signature inversion in the pi i(13/2) circle times nu i(13/2) bands in odd-odd Au-182,Au-184,Au-186 has been conducted through the standard in-beam gamma-spectroscopy techniques via the Sm-152(Cl-35,5n) Au-182, Yb-172(F-19,5n) (186)An, and Tb-159(Si-29,4n) (184)An reactions, respectively. The pi i(13/2) circle times nu i(13/2) bands in these three nuclei have been identified and extended up to high-spin states. In particular, the inter-band connection between the pi i(13/2) circle times nu i(13/2) band and the ground-state band in Au-184 has been established, leading to a firm spin-and-parity assignment for the pi i(13/2) circle times nu i(13/2) band. The low-spin signature inversion is found in the pi i(13/2) circle times nu i(13/2) bands according to our spin-assignment and-the signature crossing observed at high-spin states.
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High-resolution multi-channel seismic data and geological samples were collected during two research cruises of the R/V FENDOU 4 in 1999 and 2000. Studies on these data and samples together with results from sites 1143-1145 and 1148 of ODP Leg 184 suggest that the geological structure on the continental slope of the northern South China Sea is favorable for the formation of gas hydrates. Bottom simulating reflectors (BSRs) and geochemical anomalies which indicate the existence of gas hydrates have been recognized in sediments of the Xisha Trough, the Dongsha Rise and the accretionary wedge of the Manila subduction zone. These gas hydrates are generated by two different mechanisms depending on the tectonic regime and the seismic and geochemical characteristics. The first applies to the passive continental margin of the nor-them South China Sea on the Dongsha Rise and in the Xisha Trough. The gas hydrates are associated with diapiric structures, active faults, slumps and gravity flows as well as high Late Cenozoic sedimentation rates. Their seismic expression includes BSRs, seismic blanking zones and velocity anomalies. The second mechanism is operative on the active continental margin along the Manila subduction zone, especially in the accretionary wedge. Here, gas hydrate occurrence is marked by widespread BSRs and acoustic 'pull-down' possibly related to the existence of free gas in the sediments beneath the BSR. The thickness of the seismic blanking zones averages 250 m, suggesting that the stable gas hydrate zone has about the same thickness. (c) 2005 Elsevier Ltd. All rights reserved.
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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.
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128 samples from Ocean Drilling Program (ODP) Site 1143 in the southern South China Sea were analyzed for grain size, clay minerals, biogenic opal content and quartz in order to reconstruct changes in East Asian monsoon climate since 8.5 Ma. An abrupt change of terrigenous mass accumulation rate (MAR), clay mineral assemblage, median grain size and biogenic opal MAR about 5.2 Ma suggests that between 8.5-5.2 Ma the source of terrigenous sediment was mainly in the region of surface uplift and basaltic volcanism in southern Vietnam. A simple model of East Asian summer monsoon evolution was based on the clay/feldspar ratio, kaolinite/chlorite ratio and biogenic opal MAR. The summer monsoon has two periods of maximum strength at 8.5-7.6 Ma and 7.1-6.2 Ma. Subsequently, there was a relatively stable period at 6.2-3.5 Ma, continued intensification about 3.5-2.5 Ma, and gradually weakening after 2.5 Ma. Since I Ma the monsoon has intensified, with remarkable high-frequency and amplitude variability. Simultaneous increase in sedimentation rates at ODP Sites 1143, 1146 and 1148, as well as in MAR of terrigenous materials, quartz, feldspar and clay minerals at ODP Site 1143 at 3.5-2.5 Ma, may be the erosional response to both global climatic deterioration and the strengthening of the East Asian summer monsoon after about 3-4 Ma. (c) 2006 Elsevier B.V. All rights reserved.
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17 fotografías a color.
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MicroRNAs (miRNAs) bind to complementary sequences within the 3? untranslated region (UTR) of mRNAs from hundreds of target genes, leading either to mRNA degradation or suppression of translation. We found that a mutation in the seed region of miR-184 (MIR184) is responsible for familial severe keratoconus combined with early-onset anterior polar cataract, by deep sequencing of a linkage region known to contain the mutation. The mutant form fails to compete with miR-205 (MIR205) for overlapping target sites on the 3? UTRs of INPPL1 and ITGB4. Although these target genes and miR-205 are expressed widely, the phenotype is restricted to the cornea and lens because of the very high expression of miR-184 in these tissues. Our finding highlights the tissue-specificity of a gene network regulated by a miRNA. Awareness of the important function of miRNAs may aid identification of susceptibility genes and new therapeutic targets for treatment of both rare and common diseases.
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On lit dans les marges de cet exemplaire des gloses destinées à l'explication des mots étrangers que l'auteur est amené à citer dans son récit, ou d'autres obscurités. Manuscrit de luxe, orné d'un petit sarloh.
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