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排序方式: 共有443条查询结果,搜索用时 171 毫秒
121.
Robin A. James Andrew J. Stapleton Adam Hughes Eric Charrault Kamil Zuber Eliza Switalska Drew Evans Peter Murphy Marta Llusca 《Advanced Engineering Materials》2018,20(7)
122.
Present study has produced first detailed land‐cover map of Socotra Island. A Landsat 7 ETM+ dataset was used as a main source of remotely sensed data. From numerous reference points (more than 250) coming from the ground data verification the set of training fields and the set of evaluation fields were digitised. As a classification method the supervised maximum likelihood classification without prior probabilities was used in combination with rule‐based post‐classification sorting, providing results of sufficient accuracy and subject resolution. Estimates of the area and degree of coverage of particular land‐cover classes within Socotra Island have brought excellent overview on state of island biotopes. Overall accuracy of the map achieved is more than 80%, 19 terrestrial land‐cover classes (including three types of Shrublands, three types of Woodlands, two types of Forests and Mangroves) have been distinguished. It consequently allows estimates of the current and potential occurrence of endemic plant populations, proposals of management and conservation plans and agro‐forestry planning. 相似文献
123.
124.
Changes in zinc content and dysregulated zinc homeostatic mechanisms have been recognized in several solid malignancies such as prostate cancer, breast cancer, or pancreatic cancer. Moreover, it has been shown that zinc serum and/or tissue levels are altered in melanoma with varying effects on melanoma development and biology. This study was conducted to explore the effects of acute increases of intracellular zinc in a set of melanoma tissue explants obtained from clinical samples. Measurements of their zinc content showed an extant heterogeneity in total and free intracellular zinc pools associated with varying biological behavior of individual cells, e.g., autophagy levels and propensity to cell death. Use of zinc pyrithione elevated intracellular zinc in a short time frame which resulted in marked changes in mitochondrial activity and lysosomes. These alterations were accompanied by significantly enhanced autophagy flux and subsequent cell demise in the absence of typical apoptotic cell death markers. The present results show for the first time that acutely increased intracellular zinc in melanoma cells specifically enhances their autophagic activity via mitochondria and lysosomes which leads to autophagic cell death. While biologically relevant, this discovery may contribute to our understanding and exploration of zinc in relation to autophagy as a means of controlling melanoma growth and survival. 相似文献
125.
Kamil Klier 《Catalysis Today》1992,15(3-4):361-382
Catalyzed reactions are usually a combination of various reaction pathways that require Catalysts to possess more than one chemical function. These reaction types and Catalyst functions are reviewed and bifunctionality of Catalysts is exemplified in the ensemble control effect for oxidation of carbons to CO/CO2, double redox oxide Catalysts for partial oxidation of methane, base-hydrogenation Catalysts for methanol and higher alcohol synthesis as well as the water gas shift reaction, hydrogenation-CO insertion Catalysts for higher alcohol synthesis, and acid- hydrogenation Catalysts for the synthesis of ethers. 相似文献
126.
In serial reversal learning, subjects learn to respond differentially to 2 stimuli. When the task is fully acquired, reward contingencies are reversed, requiring the subject to relearn the altered associations. This alternation of acquisition and reversal can be repeated many times, and the ability of a species to adapt to this regimen has been considered as an indication of behavioral flexibility. Serial reversal learning of 2-choice discriminations was contrasted in 3 related species of North American corvids: pinyon jays (Gymnorhinus cyanocephalus), which are highly social; Clark's nutcrackers (Nucifraga columbiana), which are relatively solitary but specialized for spatial memory; and western scrub jays (Aphelocoma californica), which are ecological generalists. Pinyon jays displayed significantly lower error rates than did nutcrackers or scrub jays after reversal of reward contingencies for both spatial and color stimuli. The effect was most apparent in the 1st session following each reversal and did not reflect species differences in the rate of initial discrimination learning. All 3 species improved their performance over successive reversals and showed significant transfer between color and spatial tasks, suggesting a generalized learning strategy. The results are consistent with an evolutionary association between behavioral flexibility and social complexity. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
127.
Japan has been at the leading edge of location-based services (LBS) deployment using wireless assisted GPS technology. These
services, which include personal security, navigation, gaming, security and fleet management, have experienced tremendous
growth over the last few years. By looking at the factors contributing to this successful growth, LBS can be deployed in Europe
with equal success. In addition to success factors, it is important to look at the underlying wireless network technology
and its deployment impact, since Japanese deployments are based on synchronous 3G whereas Europe's likely deployments will
be based on asynchronous UMTS. Recognizing the implication of both these items in accordance with SnapTrack's vision of UMTS
LBS deployment affords a service provider a better opportunity to successfully introduce LBS and drive service revenue.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
128.
An improved metric for measuring multi-item multi-level schedule instability under rolling schedules
Disruptions in material plans due to unrealistic schedules and frequent plan revisions are common symptoms of a phenomenon generally referred to as nervousness or schedule instability in literature. A number of instability measures had been proposed so far. However, none of them deals with instability measurement comprehensively. An appropriate measurement should be able to reflect the degree of changes under rolling schedules, as well as a tool for analyzing the performance of planning systems and nervousness dampening procedures.The intent of this paper is to present a new metric for measuring multi-item multi-level schedule instability under rolling schedules and to compare it with the previous measures in literature. The new metric composed of linear combination of four sub-instability measures separates quantity and timing changes for both scheduled receipts (SRs) and planned orders (PORs). The new metric is tested by a detailed numerical example taken from literature, and results of simulation studies under various experimental factors are presented at the end of the study. 相似文献
129.
Scientific Computing Kernels on the Cell Processor 总被引:1,自引:0,他引:1
Samuel Williams John Shalf Leonid Oliker Shoaib Kamil Parry Husbands Katherine Yelick 《International journal of parallel programming》2007,35(3):263-298
In this work, we examine the potential of using the recently-released STI Cell processor as a building block for future high-end
scientific computing systems. Our work contains several novel contributions. First, we introduce a performance model for Cell
and apply it to several key numerical kernels: dense matrix multiply, sparse matrix vector multiply, stencil computations,
and 1D/2D FFTs. Next, we validate our model by comparing results against published hardware data, as well as our own Cell
blade implementations. Additionally, we compare Cell performance to benchmarks run on leading superscalar (AMD Opteron), VLIW
(Intel Itanium2), and vector (Cray X1E) architectures. Our work also explores several different kernel implementations and
demonstrates a simple and effective programming model for Cell’s unique architecture. Finally, we propose modest microarchitectural
modifications that could significantly increase the efficiency of double-precision calculations. Overall results demonstrate
the tremendous potential of the Cell architecture for scientific computations in terms of both raw performance and power efficiency. 相似文献
130.
Oender K Loeffler M Doppler E Eder M Lach S Heinrich F Karl T Moesl R Hundsberger H Klade T Eckl P Dickinson JR Breitenbach M Koller L 《Yeast (Chichester, England)》2003,20(4):281-294
Biogenesis of an active ribosome complement and a dynamic cell surface complement are two major determinants of cellular growth. In yeast, the 60S ribosomal subunit protein RpL10p/Grc5p functions during successive stages in ribosome biogenesis, specifically rRNA processing, nucle(ol)ar preribosomal subunit assembly, nucleo-cytoplasmic transport and cytoplasmic maturation of ribosomes. Here, we report that a two-hybrid screen identified yeast genes SED1, ACS2 and PLB3 as encoding proteins physically interacting with both ribosomal RpL10p/Grc5p and its human homologue hRpL10p/QMp. SED1 encodes a differentially expressed cell wall protein which is proposed to be first transiently secreted to the plasma membrane as a GPI (glycosylated derivative of phosphoinositol)-anchored form and to be then transferred to the glucan layer of the cell wall. Ectopic expression of SED1 rescues both the aberrant growth phenotype and the translation defect of grc5-1(ts) temperature-sensitive cells. Furthermore, we report that Sed1p associates with translating ribosomes suggesting a novel, cytoplasmic role for Sed1p. ACS2 encodes one of the two yeast acetyl-CoA synthases and represents a key enzyme in one of several metabolic routes to produce acetyl-CoA, which in turn is indispensable for lipid biosynthesis. PLB3 encodes a phospholipase, which is active in the breakdown of membrane lipids. Our results support the view that Grc5p/RpL10p links ribosome function to membrane turnover and cell surface biogenesis. 相似文献