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排序方式: 共有273条查询结果,搜索用时 15 毫秒
61.
用聚丙烯酰胺凝胶柱状电泳测定滑源苦荞、蒙87、大黑三棱、83—230、辽源一73和美国甜荞六种荞麦的过氧化物酶同工酶,结果表明:其酶谱带依次为五、五、三、三、三、二条,平均相对迁移率分别为0.310、0.289、0.297、0.276、0.288和0.380.据此.可得出:美国甜荞与前五种荞麦的地理起源和亲缘关系较远,而前五种亲缘关系较近,但又确有遗传差异.在抗病能力上.83—230>辽源—73>蒙—87>大黑三棱>滑源苦荞>美国甜荞.在抗寒能力上,滑源苦荞和蒙—87最耐寒,大黑三棱、83—230和辽源—73的耐寒性稍弱,而美国甜荞的耐寒力最差.  相似文献   
62.
In the present study we examined the effects of token reinforcement on the convergent control of immediate and temporally removed verbal stimuli over the verbal behavior of three school-age children with autism who showed specific deficits in intraverbal responding. Throughout the study, participants were systematically introduced to a series of visitors to a university-based autism center, and subsequently probed for information about the visitor they had most recently met. Results show that contingent token reinforcement was effective at establishing control by temporally removed verbal stimuli.  相似文献   
63.
This article focuses on a filmic portrayal of issues relating to autism in a Chinese context, using this as a prism through which to consider how meanings associated with disability in general, and the autistic spectrum in particular, are produced. Instead of perpetuating a reductive positive/negative approach to representation, the article focuses on the fluid and dynamic ways in which author and audience co-produce texts relating to disability in ways which are invariably influenced by, and reproducing of, specific socio-cultural and discursive circumstances. Meaning-making in relation to disability is, however, ongoing and there is potential to realize disability differently.  相似文献   
64.
This article describes U.S. state policies related to alcohol use during pregnancy, using data from the National Institute on Alcohol Abuse and Alcoholism Alcohol Policy Information System. Specifically, this study examines trends in policies enacted by states over time and types of policies enacted across states in the United States, with a focus on whether laws were supportive or punitive toward women. Findings revealed substantial variability in characteristics of policies (19 primarily supportive, 12 primarily punitive, 12 with a mixed approach, and 8 with no policies). Findings underscore the need to examine possible consequences of policies, especially of punitive policies and “mixed” approaches.  相似文献   
65.
Recently, Jayakumar & Pillai (1996) gave an interesting characterization of the positive Linnik laws in terms of the spectrum function of an infinitely divisible law. This paper improves their result and simplifies their proof. It proves another characterization result in terms of the Pareto law. Further, it represents the positive Linnik random variable as a function of independent gamma random variables.  相似文献   
66.
A wooden historic building located in Tibet, China, experienced structural damage when subjected to tourists visit. This kind of ancient building attends to too many visitors every day because heritage sites never fail to attract tourists. There should be a balance between accepting the visitors and the protection of historic buildings considering the importance of the cultural relics. In this paper, the singular spectrum analysis (SSA) is used for forecasting the number of tourist for the building management to exercise maintenance measures to the structure. The analyzed results can be used to control the tourist flow to avoid excessive pedestrian loading on the structure. The relationship between the measured acceleration from the structure and the tourist number is firstly studied. The root-mean-square (RMS) value of the measured acceleration in the passage route of the tourist is selected for forecasting future tourist number. The forecasting results from different methods are compared. The SSA is found slightly outperforms the autoregressive integrated moving average model (ARIMA), the X-11-ARIMA model and the cubic spline extrapolation in terms of the RMS error, mean absolute error and mean absolute percentage error for long-term prediction, whereas the opposite is observed for short-term forecasting.  相似文献   
67.
There are two main parameters in Singular Spectrum Analysis (SSA). The aim of this study is to determine whether the optimal values of these parameters are different for reconstruction and forecasting stages, and if those are worth the extra computational effort and time which they require. Here, we evaluate these issues using simulation study.  相似文献   
68.
This article describes a Bayesian small sample approach to making inferences for the operator (or filter) and squared gain of a p — th order Gaussian univariate autoregressive process. Simultaneous pos¬terior probability bands are developed for the real and the imaginary parts of the frequency-response function of an autoregressive operator as well as for the squared gain of an autoregressive process.  相似文献   
69.
研究了一类两个并联部件的可修系统的动力算子,应用泛函分析方法和C0半群理论,获得了系统算子的较细致的谱分布的结果.据此结果获得了系统解的有限表示和某些可靠性指标.  相似文献   
70.
股票价格持续大幅波动前后多重分形谱的异常及分析   总被引:5,自引:0,他引:5  
利用多重分形谱可以深入地分析金融时间序列的微观结构及其特征.本文以民生银行、长江通信二上市公司的具体数据为例,以它们出现持续大幅震荡前后共35天的5min股价高频交易序列为原始数据,并将连续5天的高频数据分为一组,考察每支股票在持续大涨及持续大跌前后各个阶段时多重分形谱的形态及其重要参数的变化.研究表明股价持续大幅波动前后,股票价格的高频时间序列的多重分形谱具有前兆性的共同特征.运用本文的研究方法可以对个股持续大幅波动的开始及结束做出一定预测.  相似文献   
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