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排序方式: 共有211条查询结果,搜索用时 15 毫秒
1.
1986改革中,加纳政府根据结构调整方案(SAP)和2020计划,关注教育中存在性别的不平等现象,努力解决女生在科学、数学和技术课程(SMT)的学业成绩、入学率等问题,并建立女子教育联合会.问题的解决要依靠真正普及免费的义务教育以及将妇女教育延伸到职业和高等教育机构. 相似文献
2.
We re-evaluate Andreu and Spanos's findings in favour of trend stationarity by considering the extended Nelson-Plosser data set. This expanded (to 1988) data set includes a period of rather different behaviour compared with the original Nelson-Plosser data used by Andreou and Spanos. We find that Andreou and Spanos's models (with only minor adjustments) exhibit remarable stability over this extended period, and indicate that their conclusions are more robust than they have shown. 相似文献
3.
洋桔梗叶盘高频率不定芽诱导的初步研究 总被引:1,自引:0,他引:1
采用正交设计法研究了细胞分裂素ZT,生长素NAA,培养基pH值和光照强度对洋桔梗叶盘不定芽诱导的影响.结果表明,实验的4个因子对洋桔梗叶盘不定芽都具有极显著的诱导作用,最佳培养基和培养条件为:MS ZT 0.5 mg/L NAA 0.01 mg/L,培养基pH值为6.3,光照强度为3000 lx.该处理中每叶盘再生不定芽数平均达9.41个. 相似文献
4.
逯文英 《长春理工大学学报(高教版)》2006,(4)
本文针对目前一些单位内部会计控制的现状,从认识内部会计控制的意义入手,通过制定切实可行的内部会计控制制度并组织实施等几个方面阐述如何加强单位内部会计控制建设。 相似文献
5.
靳贵珍 《北京理工大学学报(社会科学版)》2002,4(3):23-26
学分制是美国高等教育系统中普遍使用的衡量高校学术工作的行之有效的手段。本文对学分制在美国高等教育体制中产生的历史、发展过程及应用的范围进行了分析、探讨, 并给予了客观的评价, 最后指出了它对于中国高等教育学术管理体制的借鉴意义, 并提出了几点个人的建议。 相似文献
6.
《Journal of Statistical Computation and Simulation》2012,82(12):1145-1161
The Perron test which is based on a Dickey–Fuller test regression is a commonly employed approach to test for a unit root in the presence of a structural break of unknown timing. In the case of an innovational outlier (IO), the Perron test tends to exhibit spurious rejections in finite samples when the break occurs under the null hypothesis. In the present paper, a new Perron-type IO unit root test is developed. It is shown in Monte Carlo experiments that the new test does not over-reject the null hypothesis. Even for the case of a level and slope break for trending data, the empirical size is near its nominal level. The test distribution equals the case of a known break date. Furthermore, the test is able to identify the true break date very accurately even for small breaks. As an application serves the Nelson–Plosser data set. 相似文献
7.
《Journal of Statistical Computation and Simulation》2012,82(11):811-819
The finite-sample size properties of momentum-threshold autoregressive (MTAR) asymmetric unit root tests are examined in the presence of level shifts under the null hypothesis. The original MTAR test using a fixed threshold is found to exhibit severe size distortion when a break in level occurs early in the sample period, leading to an increased probability of an incorrect inference of asymmetric stationarity. For later breaks the test is also shown to suffer from undersizing. In contrast, the use of consistent-threshold estimation results in a test which is relatively robust to level shifts. 相似文献
8.
Interviewer characteristics affect nonresponse and measurement errors in face-to-face surveys. Some studies have shown that mismatched sociodemographic characteristics – for example gender – affect people's behavior when interacting with an interviewer at the door and during the survey interview, resulting in more nonresponse. We investigate the effect of sociodemographic (mis)matching on nonresponse in two successive rounds of the European Social Survey in Belgium. As such, we replicate the analyses of the effect of (mis)matching gender and age on unit nonresponse on the one hand, and of gender, age and education level (mis)matching on item nonresponse on the other hand. Recurring effects of sociodemographic (mis)match are found for both unit and item nonresponse. 相似文献
9.
简要介绍了盘形钻头的结构特点及工作机理,着重对盘形牙轮钻头9种不同结构参数的盘形切削齿与目前镶齿牙轮钻头上使用的瓢形和楔形齿在重庆砂岩上进行了刮切对比实验的实验数据进行了分析处理。求出了刮切实验中测得的不同牙齿在刮切过程中的刮切力的最大值、最小值、平均值和刮切单位体积岩石所需的刮切力的大小,得到了不同结构牙齿在刮切重庆砂岩时的刮切效果,为进一步设计出实用于中硬及软地层并具有较高综合工作性能的盘形钻头提供了实验数据。 相似文献
10.
A number of recent papers have focused on the problem of testing for a unit root in the case where the driving shocks may be unconditionally heteroskedastic. These papers have, however, taken the lag length in the unit root test regression to be a deterministic function of the sample size, rather than data-determined, the latter being standard empirical practice. We investigate the finite sample impact of unconditional heteroskedasticity on conventional data-dependent lag selection methods in augmented Dickey–Fuller type regressions and propose new lag selection criteria which allow for unconditional heteroskedasticity. Standard lag selection methods are shown to have a tendency to over-fit the lag order under heteroskedasticity, resulting in significant power losses in the (wild bootstrap implementation of the) augmented Dickey–Fuller tests under the alternative. The proposed new lag selection criteria are shown to avoid this problem yet deliver unit root tests with almost identical finite sample properties as the corresponding tests based on conventional lag selection when the shocks are homoskedastic. 相似文献