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201.
Amplitudes, rates, periodicities, causes and future trends of temperature variations based on tree rings for the past 2485 years on the central-eastern Tibetan Plateau were analyzed. The results showed that extreme climatic events on the Plateau, such as the Medieval Warm Period, Little Ice Age and 20th Century Warming appeared synchronously with those in other places worldwide. The largest amplitude and rate of temperature change occurred during the Eastern Jin Event (343?C425 AD), and not in the late 20th century. There were significant cycles of 1324 a, 800 a, 199 a, 110 a and 2?C3 a in the 2485-year temperature series. The 1324 a, 800 a, 199 a and 110 a cycles are associated with solar activity, which greatly affects the Earth surface temperature. The long-term trends (>1000 a) of temperature were controlled by the millennium-scale cycle, and amplitudes were dominated by multi-century cycles. Moreover, cold intervals corresponded to sunspot minimums. The prediction indicated that the temperature will decrease in the future until to 2068 AD and then increase again. 相似文献
202.
Michael P. Clements Philip Hans Franses Jeremy Smith Dick van Dijk 《Journal of forecasting》2003,22(5):359-375
We compare linear autoregressive (AR) models and self‐exciting threshold autoregressive (SETAR) models in terms of their point forecast performance, and their ability to characterize the uncertainty surrounding those forecasts, i.e. interval or density forecasts. A two‐regime SETAR process is used as the data‐generating process in an extensive set of Monte Carlo simulations, and we consider the discriminatory power of recently developed methods of forecast evaluation for different degrees of non‐linearity. We find that the interval and density evaluation methods are unlikely to show the linear model to be deficient on samples of the size typical for macroeconomic data. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
203.
研究了微小玻璃球以矩形或立方结构在硅油中加直流电场后形成的“链组”的静态导电行为。发现流过静态(无应变)单链的电流密度随外加电场强度的增加而增大,它与组成链的玻璃球数无关,但随组成“链组”的链数(1 ̄4个链)的增加而增大。由4个相互接近的单链组成的链组的电流密度约是单链电流密度的2倍。 相似文献
204.
Stem cells, asymmetric division and cancer 总被引:5,自引:0,他引:5
Clevers H 《Nature genetics》2005,37(10):1027-1028
205.
Levitus M Waisfisz Q Godthelp BC de Vries Y Hussain S Wiegant WW Elghalbzouri-Maghrani E Steltenpool J Rooimans MA Pals G Arwert F Mathew CG Zdzienicka MZ Hiom K De Winter JP Joenje H 《Nature genetics》2005,37(9):934-935
The protein predicted to be defective in individuals with Fanconi anemia complementation group J (FA-J), FANCJ, is a missing component in the Fanconi anemia pathway of genome maintenance. Here we identify pathogenic mutations in eight individuals with FA-J in the gene encoding the DEAH-box DNA helicase BRIP1, also called FANCJ. This finding is compelling evidence that the Fanconi anemia pathway functions through a direct physical interaction with DNA. 相似文献
206.
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208.
Ptprj is a candidate for the mouse colon-cancer susceptibility locus Scc1 and is frequently deleted in human cancers 总被引:21,自引:0,他引:21
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210.