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51.
金彦平 《北京林业大学学报(社会科学版)》2002,(Z1)
农业剩余劳动力的就业问题 ,是我国经济中的一个重要问题。要解决好这一问题 ,就需要制定引导农业劳动力转移的战略 ,多方寻求劳动力转移的途径 ,努力提高农业劳动力素质 ,建立健全劳动力市场 ,营造有利于农业剩余劳动力就业的制度环境 ,控制人口过快增长 相似文献
52.
林业发展阶段研究概述 总被引:2,自引:0,他引:2
阶段性是事物发展必须遵循的一个客观规律,林业的发展同样也具有阶段性.只有充分认识各个时期林业发展所处的历史阶段和相应特征,才能更好地制定政策和发展战略.该文将以往的林业方面的阶段性研究加以综述,以期获得收益和启发,并为以后的研究打下基础. 相似文献
53.
The physical and psychological effects of Turner's Syndrome, a female sex chromosome abnormality, briefly are described. Principles for helping women master the special challenges posed by the disorder are discussed. The authors argue that women with TS must take control of defining their identities and potential in order to attain full status within society. 相似文献
54.
55.
该文在查阅古文献的基础上 ,对我国古代在城市水资源合理利用与开发的同时 ,如何与改善人居环境、城市景观相结合进行了分析研究。古人的这种做法对于如何改善我国目前日益恶劣的城市生态环境以及如何使人居环境工程建设与城市景观建设密切结合 ,给予了很好的启示作用 相似文献
56.
In this paper, we study implementation in “economic environments”. It is shown that there is a dense subset of the set of preference profiles such that given an arbitrary social choice function, f, and ε>0, there exists another social choice function, f ε, within ε of f uniformly and implementable in Nash equilibrium on the dense subset. 相似文献
57.
The small sample performance of least median of squares, reweighted least squares, least squares, least absolute deviations, and three partially adaptive estimators are compared using Monte Carlo simulations. Two data problems are addressed in the paper: (1) data generated from non-normal error distributions and (2) contaminated data. Breakdown plots are used to investigate the sensitivity of partially adaptive estimators to data contamination relative to RLS. One partially adaptive estimator performs especially well when the errors are skewed, while another partially adaptive estimator and RLS perform particularly well when the errors are extremely leptokur-totic. In comparison with RLS, partially adaptive estimators are only moderately effective in resisting data contamination; however, they outperform least squares and least absolute deviation estimators. 相似文献
58.
邵玉铮 《北京林业大学学报(社会科学版)》2003,2(4):73-76
该文依据分类学的原则 ,剖析了沿用一千多年的“永字八法” ,减撇加折 ,构成了“新永字八法”。同时推出了“方圆米格” ,不仅适用于楷书 ,也可传习行、草、隶、篆诸种书体。改进后的“大小多用方圆米格” ,既可写大小多种字体 ,又能提高利用率。 相似文献
59.
Michael I. Miller Sarang Joshi David R. Maffitt James G. Mcnally Ulf Grenander 《Journal of applied statistics》1994,21(1):141-163
Most real-world shapes and images are characterized by high variability- they are not rigid, like crystals, for example—but they are strongly structured. Therefore, a fundamental task in the understanding and analysis of such image ensembles is the construction of models that incorporate both variability and structure in a mathematically precise way. The global shape models introduced in Grenander's general pattern theory are intended to do this. In this paper, we describe the representation of two-dimensional mitochondria and membranes in electron microscope photographs, and three-dimensional amoebae in optical sectioning microscopy. There are three kinds of variability to all of these patterns, which these representations accommodate. The first is the variability in shape and viewing orientation. For this, the typical structure is represented via linear, circular and spherical templates, with the variability accomodated via the application of transformations applied to the templates. The transformations form groups: scale, rotation and translation. They are locally applied throughout the continuum and of high dimension. The second is the textural variability; the inside and outside of these basic shapes are subject to random variation, as well as sensor noise. For this, statistical sensor models and Markov random field texture models are used to connect the constituent structures of the shapes to the measured data. The third variability type is associated with the fact that each scene is made up of a variable number of shapes; this number is not assumed to be known a priori. Each scene has a variable number of parameters encoding the transformations of the templates appropriate for that scene. For this, a single posterior distribution is defined over the countable union of spaces representing models of varying numbers of shapes. Bayesian inference is performed via computation of the conditional expectation of the parametrically defined shapes under the posterior. These conditional mean estimates are generated using jump-diffusion processes. Results for membranes, mitochondria and amoebae are shown. 相似文献
60.
Sources of drug information among adolescent students 总被引:1,自引:0,他引:1
E Mirzaee P M Kingery B E Pruitt G Heuberger R S Hurley 《Journal of drug education》1991,21(2):95-106
A sample of 1023 eighth and tenth grade students in small to medium-sized central Texas school districts was assessed to determine the amount of information they receive from ten sources about six categories of drugs. The amount of information males reported receiving about each drug category was significantly greater than what females reported, and the amount of information that eighth graders reported receiving about each drug category was significantly greater than what tenth graders reported. Television was the primary source of drug information for all categories of drugs except inhalants, for which friends and television were equally important sources. Parents and printed media (magazines or newspapers) were of secondary importance, followed by friends and teachers. Adolescents were less likely to receive drug-related information from experience, siblings, church, doctors, and police. The reliance on the mass media for drug information in smaller school districts is a pattern which has been previously observed in larger urban districts. This consistency suggests that mass media approaches to drug education are likely to be as effective in rural areas and smaller towns as they are among urban adolescents. Implications for television programming are discussed. 相似文献