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271.
在我国能源安全面临的一系列重大问题中,能源领域的政策规划薄弱,法律保障制度建设与管理体制改革滞后,能源供应与能源安全保障体系缺乏相关政策、法律和制度的保障。只有真正做到政策、法律和管理体制“三位一体”,才能确保国家能源安全。本文从能源安全体系建构的理论和实践出发,借鉴西方能源安全战略实践,从政策、法律和管理体制等角度,对我国能源安全体系的内在机制建构进行分析,旨在为我国与中东能源合作提供借鉴与参考。 相似文献
272.
Ignored in the flurry of new research on fathers is that fatherhood may have consequences for men. This article explores possible effects on the lives and well‐being of men for a range of fatherhood experiences. Data are drawn from the National Survey of Families and Households. The first part of this article examines whether men's varied associations with children (no children, coresident, non‐coresident, and stepfatherhood) are associated with men's psychological health and behavior, social connections, intergenerational family relations, and work behavior. We found strong evidence that fathers differ from nonfathers in their social connections, family relationships, and work behavior. There is significant variation in effects among the father types as well. The second section of this article focuses attention only on men who are fathers and examines whether fathering behavior (e.g., the amount of time and nature of the activities that fathers are reported to be spending with their children) is associated with men's well‐being. The effects of father involvement on men was found to be most significant for those who were living with their own children. 相似文献
273.
Michael Haber 《统计学通讯:模拟与计算》2013,42(4):999-1013
In 1935, R.A. Fisher published his well-known “exact” test for 2x2 contingency tables. This test is based on the conditional distribution of a cell entry when the rows and columns marginal totals are held fixed. Tocher (1950) and Lehmann (1959) showed that Fisher s test, when supplemented by randomization, is uniformly most powerful among all the unbiased tests UMPU). However, since all the practical tests for 2x2 tables are nonrandomized - and therefore biased the UMPU test is not necessarily more powerful than other tests of the same or lower size. Inthis work, the two-sided Fisher exact test and the UMPU test are compared with six nonrandomized unconditional exact tests with respect to their power. In both the two-binomial and double dichotomy models, the UMPU test is often less powerful than some of the unconditional tests of the same (or even lower) size. Thus, the assertion that the Tocher-Lehmann modification of Fisher's conditional test is the optimal test for 2x2 tables is unjustified. 相似文献
274.
Kenneth W. Wachter 《Mathematical Population Studies》2013,20(2):79-103
Age‐specific models of population renewal (with and without feedback) which imply convergence to a stable state for some levels of fertility or feedback may imply the presence of long‐term cycling around a constant or exponentially changing equilibrium for other levels of fertility or feedback. The switch from one regime to the other is a “bifurcation.”; The conditions for bifurcation involve the roots of an analogue of Lotka's Equation. Typically bifurcation is induced by raising the strength of feedback or the level of fertility. It has been known since the early 1980s, however, that this is sometimes impossible. It is sometimes impossible even with the linear renewal equation itself and with the most basic of non‐linear models, Lee's cohort feedback model. Here it is proved that this typical route to bifurcation does not fail for these basic models in the presence of a condition which always holds for realistic applications with higher organisms: the existence of a span of ages before the onset of fertility. Specifically, a strictly positive lower bound on ages of procreation is proved to be sufficient to guarantee the existence of a rescaling of Lotka's Equation for which the real part of some complex root vanishes. This result holds for absolutely Lebesgue‐integrable (signed) net maternity functions on the positive real line and for absolutely summable (signed) net maternities on the positive integers. It follows that Coale's rescaling device for the analysis of approach to stability in stable population theory can be implemented for all realistic human net maternity schedules. It also follows that the many special cases of the cohort feedback model throughout population biology will all generate persistent cycling instead of stability if feedback is sufficiently strong. 相似文献
275.
《Journal of women & aging》2013,25(1):75-95
ABSTRACT This paper is based on the findings of small group discussions with self-defined successful African American women age 60+ in Charlotte, North Carolina. These women, who lived through the Jim Crow era and thrived in spite of the obstacles, continue to seek meaning in their lives through the roles they play in their families, churches, and communities. They feel strongly that there is a core of key values that continue to hold meaning and struggle to impart these values to those whose lives they touch. The key values identified include education, religion, work, and giving back to the community, and illustrate the integration of both traditional and nontraditional definitions of success. Mentoring is proposed as an important concept for understanding the lives of African American women in later life. 相似文献
276.
《Journal of gerontological social work》2013,56(1-2):101-111
No abstract available for this article. 相似文献
277.
许智银 《河南科技大学学报(社会科学版)》2009,27(2):46-49
唐代送别诗中的意象组合极具特色,诗人巧妙利用送别时的地点、行人所往之地以及沿途的文化特色形成的空间地点意象组合,造成了峰断云连、辞断意属的审美意境;借用明显的时令节侯、景物气象等特点组合的意象,则增添了送别诗意象的斑斓色彩和艺术感染力。 相似文献
278.
在西方现代化进程中,科学极大地解放了人的智力和体力,为人的自由发展提供了条件。然而,当科学的权威急剧膨胀变异成科学霸权主义,科学成为奴役人的工具时,却造成了人的困境。我国正处于现代化建设的进程中,需要吸收和借鉴西方科学发展进程中的经验和教训,发展一种厚道的、有机的科学具有重要的现实意义。 相似文献
279.
Consider a random variable S being the sum of a number N of independent and identically distributed random variables Xj (j = 1, 2, ...) where the number N is itself a non-negative integer-valued random variable independent of the Xj An explicit expression of the r-th cumulant of S is given in terms of the cumulants of N and Xj, Asymptotic properties of the distribution of S are also discussed. 相似文献
280.
当前中国社会有关70后和80后之间的各种争论层出不穷,主要集中在性观念等道德观的层面,例如,许多人认为80后在性观念上面比70后更为开放,但是缺乏严谨的数据论证。因此,本文使用CGSS(中国综合社会调查)2005年的数据对此进行了分析,发现70后、80后这种基于年龄的代际概念并没有统计上的意义,即在控制相关变量后,这两个年龄阶段群体的性观念开放程度并不存在显著的差异。 相似文献