世界各国聚焦氢能源经济

氢是宇宙中最丰富的元素，地球上分布着大量的氢，其来源丰富。氧还是元素周期表中最轻的一个元素，与其他物质相比，具有较高的重量比能量。氢的燃烧产物是水，非常清洁，不会对环境造成污染。因此人们对氢能源的开发与利用也产生了极大的兴趣。     

Four tests of fit for the beta-binomial distribution

Tests based on the Anderson–Darling statistic, a third moment statistic and the classical Pearson–Fisher X ² statistic, along with its third-order component, are considered. A small critical value and power study are given. Some examples illustrate important applications.     

Puerto rican drug users’ experiences of physical and sexual abuse: Comparisons based on sexual identities

This study integrates the results of quantitative and qualitative methods to elucidate the association between sexual identity and physical and sexual abuse among Puerto Rican drug users. A structured questionnaire was administered to 800 subjects in New York and 399 in Puerto Rico. A total of 93 subjects (7.9%) self‐identified as homosexual or bisexual. Gay males were significantly more likely than heterosexual males to report first occurrence of physical abuse by a family member in childhood. Both gay and bisexual males were more likely than their heterosexual counterparts to report first experiencing unwanted sex in childhood and intimate partner physical abuse later in life. Lesbians were more likely than female heterosexuals to report unwanted sex in childhood. Qualitative data were collected through in‐depth life histories with 21 subjects and suggest that gay and lesbian subjects perceive antihomosexual prejudice on the part of family members as one cause of childhood physical and sexual abuse.     

Second Quarter 1973 Survey of the Economic Outlook

The aim of the author is improvement of statistical practice. The author distinguishes between enumerative studies and analytic studies. An enumerative study has for its aim an estimate of the number of units of a frame that belong to a specified class. An analytic study has for its aim a basis for action on the cause-system or the process, in order to improve product of the future. A fair price to pay for an inventory is an example of an enumerative study. Tests of varieties of wheat, insecticides, drugs, manufacturing processes, are examples of analytic studies: the choice of variety or treatment will affect the future out-turn of wheat, future patients, future product. Techniques and methods of inference that are applicable to enumerative studies lead to faulty design and faulty inference for analytic problems.

It is possible, in an enumerative problem, to reduce errors of sampling to any specified level. In contrast, in an analytic problem, it is impossible to compute the risk of making a wrong decision. The author provides a number of examples, and pleads for greater care in the writing and teaching of statistical theory and inference.     

The Job Demands-Job Control Model and absence behaviour: results of a 3-year longitudinal study

Empirical results of earlier studies only marginally supported the relevance of Karasek's Job Demands-Job Control Model for absence behaviour. Since longitudinal studies with respect to these relations were largely lacking, a four-wave panel study was carried out using data from 1755 male employees of a technical maintenance firm in the public sector. Job demands, job control, physical working conditions, and the employee's age, education, and health were measured in one year and absenteeism in the same year and in the next 3 years. Data were analysed with linear regression and Poisson regression techniques. The Poisson regression technique was superior to the linear regression technique in explaining absence. Age, health and prior absence were the best predictors of later absence behaviour. With respect to the Job Demands-Job Control Model, the main findings of the study were (1) that job control was significantly associated with a low number of simultaneous and later absence days, and (2) that, contrary to expectations, job demands were also related to a low number of simultaneous and later absence days. These results hold when age, health, education, prior absence, and working conditions are controlled for. Job control and job demands did not predict later absence frequency. In the discussion it is suggested that a high level of job demands may not only be harmful for the well-being of employees but also work as 'a pressure to attend'.     

Using adaptive weighted least squares to reduce the lengths of confidence intervals

The author proposes an adaptive method which produces confidence intervals that are often narrower than those obtained by the traditional procedures. The proposed methods use both a weighted least squares approach to reduce the length of the confidence interval and a permutation technique to insure that its coverage probability is near the nominal level. The author reports simulations comparing the adaptive intervals to the traditional ones for the difference between two population means, for the slope in a simple linear regression, and for the slope in a multiple linear regression having two correlated exogenous variables. He is led to recommend adaptive intervals for sample sizes superior to 40 when the error distribution is not known to be Gaussian.     

The Renewed Search for Social Trusteeship: Cohen and Fitch on Social Justice and the City

It has become a commonplace to argue that in the face of a discredited Marxism, socialism must find an alternative basis for a renewed project. This article investigates two of these claims by Gerald Cohen and Bob Fitch. It does so with particular reference to the attempt by these authors to re-invoke, both wittingly and unwittingly, David Ricardo, John Stuart Mill, Henry George, and Auguste Comte among others as the source of a renewed left project. It takes as its special concern the way in which the supposed need to revivify "industry" in the late twentieth century parallels the often voiced need to revivify "agriculture" in the late nineteenth century as a means of staving off "underdevelopment."     

Cross-country determinants of life satisfaction: exploring different determinants across groups in society

This paper explores a wide range of cross-country determinants of life satisfaction exploiting a database of 90,000 observations in 70 countries. We distinguish four groups of aggregate variables as potential determinants of satisfaction: political, economic, institutional, and human development and culture. We use ordered probit to investigate the importance of these variables on individual life satisfaction and test the robustness of our results with Extreme Bounds Analysis. The results show that only a small number of factors, such as openness, business climate, postcommunism, the number of chambers in parliament, Christian majority, and infant mortality, robustly influence life satisfaction across countries while the importance of many variables suggested in the previous literature is not confirmed. This remains largely true when the analysis splits national populations according to gender, income, and political orientation also. We thank Stephen Lea, participants at the 30th IAREP conference in Prague and the referees of this journal for comments on earlier versions. Gilles Winkler provided excellent research assistance.