我国农业资源法制建设问题探讨

农业资源　法是我国资源法体系的重要组成部分。当前,农业资源立法采取的是以自然资源构成要素为法律调整对象的立法模式,主要确立了权属、调查评价、规划、保护和许可审批制度,仍处于单项法律、法规为主的群法状态。法制体系不健全、内容不完善、与市场经济的经济运行机制农业资源、法律制度     

反倾销对抗博弈——兼论我国少有对外反倾销申诉的成因分析

本文首先对国际反倾销现状进行了分析,结果表明国际反倾销近３０年来愈演愈烈,尤其是对华反倾销的地位在急剧上升,究其原因是什么吗？作者建立了一个完全信息反倾销对抗博弈模型对此给予了理论解释,并经实证分析指出了在国际反倾销浪潮中我国少有对外反倾销申诉的成因,主要是专职管理投入不足、产业集中度低和不擅长反倾销博弈等,文末指出模型在许多领域具有普遍的拓展应用前景,可以类推解释许多对抗博弈问题。     

航天型号费用估算随机不确定性的优化综合

本文论术字复杂的技术和外界环境条件下,三遇用估算方法涉及到的随机不确定性及其表征参数－标准差,通过采用最小线性方差组合,实现了三种费用估算方法随机不确定性的优化综合,对方法之间存在非零协方差的情况。本文也给出了相应的求解方法。     

Lipid peroxidation and spectrin of RBC membrane in hydroxyurea treated Eβ thalassaemia

The aim of the present work is to understand the effect of low dose of hydroxyurea (HU) therapy on oxidative damage of RBC membrane in non-transfused Eβ thalassaemia. HU was administered at a dose of 30 mg/kg/day for 90 consecutive days. The percentage of spectrin and the level of malondialdehyde (MDA), fetal hemoglobin (HbF), hemoglobin (Hb) and packed cell volume (PCV) were measured. The HbF level was significantly increased after 90 days of HU therapy. MDA level of RBC membrane was decreased. There was no change in PCV, Hb and spectrin content of RBC membrane after HU therapy for 90 days in Eβ thalassaemia. Increment of HbF in HU treated Eβ patient may have some role on the correction of oxidative damage of RBC membrane by inhibiting further degradation of spectrin and by decreasing lipid peroxidation of red cell membrane.     

On the excitability of a class of positive continuous time-delay systems

This article is on the excitability of positive linear time-invariant systems subject to internal point delays. It is proved that excitability independent of delay is guaranteed if an auxiliary delay-free system is excitable. Necessary and sufficient conditions for excitability and transparency independent of the delay size are formulated in terms of the parameterization of the dynamics and control matrices. Some particular results are also given for the properties being dependent on the size of the point delay and for any possible finite values of the delay. The same formulation is given in parallel in terms of strict positivity of a matrix of an associate system obtained from the influence graph of the original system. The excitability and transparency properties are both testable through simple algebraic tests involving a moderate computational effort that is directly related to the system's order.     

Hybrid clustering for validation and improvement of subject-classification schemes

A hybrid text/citation-based method is used to cluster journals covered by the Web of Science database in the period 2002–2006. The objective is to use this clustering to validate and, if possible, to improve existing journal-based subject-classification schemes. Cross-citation links are determined on an item-by-paper procedure for individual papers assigned to the corresponding journal. Text mining for the textual component is based on the same principle; textual characteristics of individual papers are attributed to the journals in which they have been published. In a first step, the 22-field subject-classification scheme of the Essential Science Indicators (ESI) is evaluated and visualised. In a second step, the hybrid clustering method is applied to classify the about 8300 journals meeting the selection criteria concerning continuity, size and impact. The hybrid method proves superior to its two components when applied separately. The choice of 22 clusters also allows a direct field-to-cluster comparison, and we substantiate that the science areas resulting from cluster analysis form a more coherent structure than the “intellectual” reference scheme, the ESI subject scheme. Moreover, the textual component of the hybrid method allows labelling the clusters using cognitive characteristics, while the citation component allows visualising the cross-citation graph and determining representative journals suggested by the PageRank algorithm. Finally, the analysis of journal ‘migration’ allows the improvement of existing classification schemes on the basis of the concordance between fields and clusters.     

情报学研究生教育回顾与前瞻

本文对中国科学技术信息研究所情报教育,特别是情报学研究生教育进行了回顾、总结和展望.同时也对中国情报学研究生教育事业30年来的发展做了简要回顾和思考.     

A packaged intervention to reduce disruptive behaviors in general education students

This investigation employed a combination multiple baseline/reversal design across individuals to examine the effects of a packaged intervention designed to reduce disruptive behaviors in two 8‐year‐old female students, with a third 8‐year‐old female student serving as a control. The intervention was delivered through a contingency contract and was comprised of precision requests, antecedent strategies (i.e., public posting of classroom rules, and teacher movement), positive reinforcement (i.e., mystery motivators, token economy), and the reductive technique of response cost.During baseline, the percentage of intervals that the students evidenced disruptive behaviors averaged 41%. This was reduced to an average of 20% during treatment. In the withdrawal phase, disruptive intervals increased to an average of 25%. Reinstatement of the intervention resulted in a further reduction of disruptive intervals of 20%. © 2000 John Wiley & Sons, Inc.     

甘肃藏敦煌藏文文献概述

本文对甘肃各地收藏的敦煌莫高窟藏经洞出土的吐蕃文文献(敦煌藏文文献)作了简要的介绍,重点对敦煌市博物馆藏梵夹式经页《十万般若颂》的分类叙述;同时就甘肃藏敦煌藏文文献的价值、意义作出初步判断.     

Relating students' reasoning to the history of science: The case of chemical equilibrium

In this study, the reasoning of students, who are introduced to the concept of chemical equilibrium, was related to the historical development of this concept. In the first stage of the study, remarkable similarities were observed between students' reasoning on the issue of incomplete chemical conversions and the reasoning of 19th-century scientists, especially when molecular notions were included. In the next stage of the study, some authentic problems and questions, that were essential in the historical development of chemical equilibrium, were presented to students. It appeared that they recognised the significance of these problems and questions. Moreover, most students were eager to find explanations. Students, reasoning in molecular terms, would sometimes explain these problems in terms similar to historical explanations. Other students, however, suggested explanations in non-molecular terms, which, although chemically valid, did not appear to have historical antecedents. It was concluded that the study of authentic historical sources may inspire the design of effective teaching activities.