垂叶榕的生物学习性及栽培管理技术

垂叶榕是城市绿化和园林造景中应用的一种重要树种,本文就垂叶榕的生物学习性及在绿化和盆景制作中的管理技术作一简要概述。     

The econometrics of female labor supply and children

This is a survey of applied econometric research on the effects of children on female labor supply. Reasons for interest in the topic, and a basic model and terminology, are reviewed. Concerns are raised about the possible endogeneity of child status variables, and about the instrumental variables approach for dealing with this problem. Alternative ways of conceptualizing and estimating child status effects are considered, together with selected empirical evidence. Relevant developments from the household demand literature are summarized. Basic issues of model choice are also discussed.     

新资本结构理论综述

随着资本结构研究的深入,理论界进一步放宽MM定理的基本假设。以Jensen,Myers,Ross,Leland,Harris,Hart等学者为代表的新资本结构理论引入最新的研究方法,对资本结构展开分析。本文按照新资本结构理论发展的历史轨迹,全面评述了资本结构理论中最为重要的各种理论,同时系统地描述了各有关理论的基本内容。     

Why do French women have more children than German women? Family policies and attitudes towards child care outside the home

French mothers are still more often economically active than their German counterparts and birth rates in France remain higher than in West Germany. By comparing two countries with many similarities in their family policies, I try to demonstrate that the differences between state policies per se should not be overestimated in explaining the persistent gap in their fertility level. As far as women's attitudes towards child care outside of the home are concerned, there is a strong divide between France and West Germany. In the Old Länder in Germany there is some congruence between attitudes and beliefs towards child care and the shortage of child care provision, especially for toddlers. As a product of the interaction between shortage of child care provision, women's attitudes regarding child care and mothers' low labour force participation rate, German family policy reinforces these attitudes. Conversely, there is slow impetus for policy makers to really develop a comprehensive public child care system. Against this cultural and institutional background, an increasing number of women give priority to their job or to their career. In France, by contrast, norms in respect of education of toddlers and young children have evolved in tandem with the change in attitudes of women towards employment. A majority of French women feel legitimised to be in employment on a full-time basis and to have their children cared for outside the home. Their attitudes are in tune with the premises of family policy which has integrated the model of 'the employed mother'. Les Francaises continuent àavoir plus d'enfants que les Allemandes de l'Ouest alors que les différences entre les taux d'activité des mères se sont progressivement atténuées. La proportion de femmes qui n'ont pas d'enfants, en particulier, est beaucoup plus importante en Allemagne de l'Ouest. En comparant deux pays dont les politiques sociales et familiales présentent des similarités, on se propose d'aller au delà des explications les plus couramment admises. En France, contrairement à l'Allemagne de l'Ouest, les normes régissant l'éducation des jeunes enfants ont évolué en phase avec les changements qui ont affectéles comportements des femmes sur le marché du travail. Il est devenu légitime socialement pour les Francaises de travailler à plein temps tout en faisant garder son enfant à l'extérieur du domicile. Les Allemandes de l'Ouest, par contre, intériorisent toujours fortement la norme selon laquelle l'éducation d'un jeune enfant nécessite la présence permanente de sa mère. Mais de plus en plus éduquées, elles sont amenées à accorder la priorité à leur maintien dans l'emploi et à renoncer à la maternité. Pour mieux comprendre les différences de fácondité entre les deux pays, il semble donc fructueux de se focaliser sur les interactions à l'aeuvre entre leurs politiques familiales, les valeurs auxquelles adhèrent la majorité des couples concernant l'éducation des jeunes enfants et les attitudes des femmes face au travail rémunéré.     

The transition to parenthood in Puerto Rico: Occupational status and the timing of first births

This study examines the relationship between occupational status and fertility timing during a period of rapid development in Puerto Rico. Our fundamental hypothesis is that women with higher status occupations face greater opportunity costs than those with less valued jobs and therefore will be more likely to postpone parenthood until later ages than women without such high costs. We test this hypothesis using event history techniques with data from the 1982 Puerto Rico Fertility and Family Planning Assessment, an island-wide survey of women between the ages of 15 and 49. The analysis examines the effects of occupational status on the timing of first births, and finds strong support for the basic hypothesis, especially regarding the post-ponement of teen births. After the teen years, the effects are less pronounced. Overall, it appears that employment opportunities have played an important role in childbearing decisions in Puerto Rico.An earlier version of this paper was presented at the annual meeting of the Population Association of America, Denver, Colorado, 30 April–2 May 1992.     

用于分散电压控制的规则库法

电力系统正常运行时,无功/电压控制目的是安全经济供电.而在紧急情况下,首要目标是运行的安全性,其次才是经济性.本文提出的局部网概念及其灵敏度矩阵,以及对电压违限严重性的分级和控制战略,使控制更为快速有效.此法更适用于当事故引起全系统运行数据不全时对局部网的电压控制.     

Construction of Fuzzy Control Charts Based on Weighted Possibilistic Mean

The problem of constructing control charts for fuzzy data has been considered in literature. The proposed transformation approaches and direct fuzzy approaches have their advantages and disadvantages. The representative values charts based on transformation methods are often recommended in practical application. For representing a fuzzy set by a crisp value, the weight of importance of the members assigned with some membership levels in a fuzzy set should be considered, and the possibility theory can be employed to deal with such problem. In this article, we propose to employ the weighted possibilistic mean (WPM), weighted interval valued possibilistic mean (WIVPM) of fuzzy number as a sort of representative values for the fuzzy attribute data, and establish new fuzzy control charts with WPM and WIVPM. The performance of the charts is compared to the existing fuzzy charts with a fuzzy c-chart example via newly defined average number of inspection for variation of control state.     

动词复制句中的附加语控制

动词复制句（Verb－Copying Construction，VCC）是一种在汉语口语中经常使用的结构，用符号可以简单地表示为S＋VP1＋VP2，动词V2是动词V1的拷贝。这种结构本身具有独特的句法语义特征，也具有不同的句法变体。在其进行句法运算时，两个动词性结构首先独立运算，VP1作为附加语，VP2作为主句成分进入句法推导。通过附加语侧向移位、附加合并以及主题化特征核查等句法操作形成语言表达式。其句法变体的不同构型是因为不同的控制类型造成的。     

An integrated model based on statistical process control and maintenance for two-stage dependent processes

The close relationship between quality and maintenance of manufacturing systems has contributed to the development of integrated models which use the concept of statistical process control (SPC) and maintenance. This article demonstrates the integration of the Shewhart individual-residual (Z_X ? Z_e) joint control chart and maintenance for two-stage dependent processes by jointly optimizing their policies to minimize the expected total costs associated with quality, maintenance and inspection. To evaluate the effectiveness of the proposed model, two stand-alone models—a maintenance model and an SPC model—are proposed. Then a numerical example is given to illustrate the application of the proposed integrated model. The results show that the integrated model outperforms the two stand-alone models with regard to the expected cost per unit time. Finally, a sensitivity analysis is conducted to develop insights into time parameters and cost parameters that influence the integration efforts.     

Neighborhood conditions,religious coping,and uncontrolled hypertension

The purpose of this study is to see whether God-mediated control beliefs moderate the relationship between living in rundown neighborhoods and uncontrolled hypertension. God-mediated control refers to the belief that God will help people handle the stressors that arise in life. Data are provided by a nationwide survey of adults (N = 1919). Three ways of assessing uncontrolled hypertension are examined: a binary format contrasting people with and without uncontrolled hypertension, systolic and diastolic blood pressure scored continuously, and a four ordinal category scheme recommended by the American Heart Association. The data suggest that stronger God-mediated control beliefs moderate the relationship between neighborhood conditions and uncontrolled blood pressure when blood pressure is scored continuously and when the American Heart Association scheme are used as outcomes.