融资约束背景下的企业研发投入与新产品开发绩效——基于中国工业企业数据库的面板模型分析

以往研究对于企业研发投入强度与新产品开发绩效之间的互动关系存在着正向影响与负向影响的不同结论,原因之一在于未考虑融资约束等情境因素的影响。从融资约束的视角研究企业研发投入强度与新产品开发绩效之间的影响关系,基于构建面板回归模型的方法和中国工业企业数据,实证结果表明:(1)进一步验证了研发投入强度与新产品开发绩效之间的正向关系的存在;(2)研发投入强度与新产品开发绩效存在着非线性倒U型关系;(3)检验了融资约束存在的调节效应,内部融资约束与外部融资约束对于上述关系的影响不同。研究结果可以为企业、政府和金融机构共同促进形成新产品研究提供理论与政策指引。     

儿童词汇习得:社会语用认知的发展过程——儿童词汇习得理论假设评述

有关儿童习得词汇的研究主要有三种理论假设 :联想学习理论、制约原则论和社会语用理论。本文在分析前两种词汇习得理论缺陷的基础上 ,着重对社会语用认知理论进行了评述。该理论强调 ,具有可塑性的、强有力的社会认知技能是儿童成功习得词汇的关键因素     

约束非线性l1问题的极大熵方法

本文给出求解约束非线性l1问题的极大熵方法并证明了其收敛性。给出了极大熵与增广La grange乘子法相结合的算法 ,最后给出一个算例。     

诺齐克的个人权利思想探究--读诺齐克的《无政府、国家与乌托邦》札记

针对现代西方资本主义社会的“平等”与“自由”的矛盾，诺齐克提出他的个人权利思想。个人权利思想贯穿于他的《无政府、国家与乌托邦》，也是他理论的出发点。文章就其理论中最弱意义上的国家、道德边际约束、资格理论和个人天赋等方面探讨了诺齐克的这一思想。     

浅析晚清实业教育发展的制约因素

作为中国职业教育的初始阶段,晚清产生的实业教育是中国新式教育的主要内容之一。实业教育虽然产生较早,但发展缓慢、曲折,始终没有成为中国近代教育的主流。制约实业教育发展的因素很多,主要有资金不足、师资不足、生源不足、管理不力等,其中最根本的还是经济动力不足,即晚清时期的资本主义经济发展缓慢,既不能为实业教育提供必要的资金,也不能消化实业教育的成果。在以上多种因素的综合作用下,晚清实业教育始终没有发展起来,其作用也远没有发挥出来。     

Financing constraints and corporate investment： an empirical analysis of china＇s manufacturing firms

With the measurement of dividend payout ratio, logistic regression index value and the firm size financing constraints, this paper investigated the investment behavior of China＇s manufacturing firms over the period from 1998 to 2003, and the relationship between financing constraints and corporate investment using the OLS regression method. The empirical evidence shows that there are certain extent financing constraints in China＇s manufacturing firms, but the results are different with different variables to measure the financing constraints.     

当代中国政治稳定的制约因素与对策

改革也是解放生产力，发展才是硬道理，稳定是中国的最高利益，这是邓小平提出的三个经典性论断，改革开放20余年来，中国创造出人类经济发展史上罕见的奇迹，其根源之一就是政治稳定，然而，发展的进程既是国家和社会进步的过程，又是不断地产生和消除不稳定因素的过程，影响中国政治稳定的主要因素有三个：一是人均收入差距的扩大和地区经济发展水平的悬殊；二是农村土地承包中的问题；三是下岗职工的生活保障问题。要保持政治稳定，必须深化国有企业改革，提高其经济效益；加大扶贫力度；充分提供就业机会；坚持就业机会；坚持四项基本原则；坚持以法治国的方针。     

Developing rigid constraint for the estimation of pose and structure from a single image

Pose and structure estimation from a single image is a fundamental problem in machine vision and multiple sensor fusion and integration.In this paper we propose using rigid constraints described in different coordinate frames to iteratively estimate structural and camera pose parameters.Using geometric properties of reflected correspondences we put forward a new concept,the reflected pole of a rigid transformation.The reflected pole represents a general analysis of transformations that can be applied to both 2D and 3D transformations.We demonstrate how the concept is applied to calibration by proposing an iterative method to estimate the structural parameters of objects.The method is based on a coarse-to-fine strategy in which initial estimation is obtained through a classical linear algorithm which is then refined by iteration.For a comparative study of performance,we also implemented an extended motion estimation algorithm(from 2D-2D to 3D-2D case)based on epipolar geometry.     

Women Scientists in Academia: Geographically Constrained to Big Cities, College Clusters, or the Coasts?

Women scientists in academia have been shown to be less geographically mobile than their male counterparts, a factor that may exacerbate gender inequities in faculty representation, tenure, and salary. This study examines the extent to which the jobs of academic women scientists are disproportionately concentrated in large cities, areas with many colleges and universities, and regions where most doctorates are granted. We also investigate whether jobs in these locations affect salary, tenure, full-time faculty status, and employment outside one's field of training in ways that differ for women and men. Our analysis is guided by arguments that geographic constraints on women's mobility are rooted in social factors, such as gender roles and mate selection patterns. Data are drawn from over 13,000 faculty respondents in the national Survey of Doctoral Recipients, representing 22 science and engineering disciplines and over 1,000 4-year colleges or universities. Regression analysis reveals that, irrespective of their family status, women faculty are more likely than their male counterparts to reside in doctoral production centers, areas with large clusters of colleges, and large cities. Responsibility for children intensifies women's geographic concentration more than marriage does and in ways that differ from men. Geographic concentration also appears generally more harmful to women's careers than to men's. Women in doctoral production centers are less likely to have tenure and more likely to work part time; those in larger cities are more likely to be in jobs off the tenure track. Locales with many colleges appear to present somewhat better career prospects for women.     

Fractions as the Coordination of Multiplicatively Related Quantities: A Cross-Sectional Study of Children's Thinking

Although equal sharing problems appear to support the development of fractions as multiplicative structures, very little work has examined how children's informal solutions reflect this possibility. The primary goal of this study was to analyze children's coordination of two quantities (number of people sharing and number of things being shared) in their solutions to equal sharing problems and to see to what extent this coordination was multiplicative. A secondary goal was to document children's solutions for equal sharing problems in which the quantities had a common factor (other than 1). Data consisted of problem-solving interviews with students in 1st, 3rd, 4th, and 5th grades (n=112). We found two major categories of strategies: (a) Parts Quantities strategies and (b) Ratio Quantities strategies. Parts quantities involved children's partitions of continuous units expressed in terms of the number of pieces that would be created. Ratio quantities involved children's creation of associated sets of discrete quantities. Within these strategies, children drew upon a range of relationships among fractions, ratio, multiplication, and division to mentally or physically manipulate quantities of sharers and things to produce exhaustive and equal partitions of the items. Additionally, we observed that problems that included number combinations with common factors elicited a wider range of whole-number knowledge and operations in children's strategies and therefore appeared to support richer interconnections than problems with relatively prime or more basic number combinations.