Welfare generosity, pregnancies and abortions among unmarried AFDC recipients

Even before the 1996 overhaul of the U.S. welfare system, a number of states had ended the practice of paying extra benefits to families who have additional children while receiving welfare. Proponents believe that this reform can reduce births to recipients, however many worry that it may encourage women to obtain abortions. Using a sample of unmarried AFDC recipients from the NLSY, we estimate a bivariate probit model of pregnancy and, conditional on becoming pregnant, the probability of abortion. Our results lend some support for the proposition that reducing incremental AFDC benefits will decrease pregnancies without increasing abortions. Received: 16 April 1998/Accepted: 11 March 1999     

The duration of unemployment in Russia

This paper uses longitudinal survey data to assess factors affecting the duration of unemployment in Russia. We examine four types of marginalised labour force participants, according to ILO guidelines and survey responses, and we estimate duration models for each type. It turns out that the sets of characteristics with the strongest effects on the duration are remarkably similar across the different unemployment definitions and model specifications. Therefore, despite the formidable practical measurement problems, problematic groups of individuals can actually be identified. Received: 27 January 1999/Accepted: 27 January 2000     

The macroeconomics of fertility in small open economies: A test of the Becker-Barro model for The Netherlands and New Zealand

Becker and Barro (1988) formulated a theoretical model which identified a range of macroeconomic variables which can temporarily or permanently affect fertility in small open economies. This article tests the Becker-Barro model with relevant data which covers most of the 20th century for two small open economies, namely The Netherlands and New Zealand. The results show that government subsidies for having children have a strong positive effect on fertility, while the provision of public pensions has a strong negative effect. The degree of intergenerational altruism appears to have been declining. Moreover, there is only weak support for the hypothesis that real interest rates positively influence fertility. Received: 2 March 1998/Accepted: 1 September 1999     

Age structure effects and growth in the OECD, 1950–1990

Economic growth depends on human resources and human needs. The demographic age structure shapes both of these factors. We study five-year data from the OECD countries 1950–1990 in the framework of an age structure augmented neoclassical growth model with gradual technical adjustment. The model performs well in both pooled and panel estimations. The growth patterns of GDP per worker (labor productivity) in the OECD countries are to a large extent explained by age structure changes. The 50–64 age group has a positive influence, and the group above 65 contributes negatively, while younger age groups have ambiguous effects. However, the mechanism behind these age effects is not yet resolved. Received: 16 January 1997/Accepted: 2 July 1998     

A seasonal mixed-POT model to estimate high flood quantiles from different event types and seasons

Flood events can be caused by several different meteorological circumstances. For example, heavy rain events often lead to short flood events with high peaks, whereas snowmelt normally results in events of very long duration with a high volume. Both event types have to be considered in the design of flood protection systems. Unfortunately, all these different event types are often included in annual maximum series (AMS) leading to inhomogeneous samples. Moreover, certain event types are underrepresented in the AMS. This is especially unsatisfactory if the most extreme events result from such an event type. Therefore, monthly maximum data are used to enlarge the information spectrum on the different event types. Of course, not all events can be included in the flood statistics because not every monthly maximum can be declared as a flood. To take this into account, a mixture Peak-over-threshold model is applied, with thresholds specifying flood events of several types that occur in a season of the year. This model is then extended to cover the seasonal type of the data. The applicability is shown in a German case study, where the impact of the single event types in different parts of a year is evaluated.     

On the power of durbin-watson statistic against fractionally integrated processes

This paper provides the theoretical explanation and Monte Carlo experiments of using a modified version of Durbin-Watson ( D W ) statistic to test an 1 ( 1 ) process against I ( d ) alternatives, that is, integrated process of order d, where d is a fractional number. We provide the exact order of magnitude of the modified D W test when the data generating process is an I ( d ) process with d E (0. 1.5). Moreover, the consistency of the modified DW statistic as a unit root test against I ( d ) alternatives with d E ( 0 , l ) U ( 1 , 1.5) is proved in this paper. In addition to the theoretical analysis, Monte Carlo experiments show that the performance of the modified D W statistic reveals that it can be used as a unit root test against I ( d ) alternatives.     

Language in the process of labour market rationalisation: A sociohistorical approach across twentieth-century Spain

This article analyses the role of linguistic skills in the process of defining professional classifications in Spain during 1919–1980. The aim is to determine the social evaluation of the skills involved. To retrace the classifications, a total of 114 official documents were examined, establishing a chronological division into three major stages: 1920–1940, 1940–1960 and 1960–1980. The first period (1920–1940) shows efforts toward the initial objectification of working conditions and salary scales, revealing social prejudices and tacit conventions shaping the employment hierarchy, while the second one (1940–1960) indicates the extent to which office work stood out over manual work. Finally, the third stage (1960–1980) shows processes of language rationalisation, which entailed attempts to standardise positions based on required skill sets.     

试述北魏宗室阶层的犯罪类型

北魏宗室阶层是政权的柱石、统治集团的核心,在政治和社会领域里享受充分的特权,北魏时期的法律反映了宗室特权的主要方面.由于拓跋鲜卑历经由游牧部落向文明国家阶段的跃进,宗室成员在身份角色的转换过程中不可避免地会与国家法制和名教礼法发生冲突,表现为具体的犯罪行为.北魏宗室非违主要有政治犯罪、职务犯罪、刑事犯罪和悖逆纲常伦理四类.各类罪行的时间分布特点和惩治力度集中反映出宗室生存境遇的改变和王朝政局的走势.     

可持续发展的产业分类理论——立体产业分类理论

本世纪 60年代以来 ,自然资源产业、环保产业、高新技术产业 (包括信息产业 )等新兴产业迅速发展 ,其对可持续发展的促进作用 ,已经为各国经济发展的实践所证明 ,也给产业经济研究提出了现实的问题。传统产业分类理论没有对新兴产业的内涵、归属及其在产业结构中的地位等加以揭示 ,使得建立在传统产业分类理论基础上的产业结构演进理论解释现象、指导经济实践的能力减弱。作者在深入分析传统产业分类理论的局限的基础上 ,提出可持续发展的产业分类理论