Antidepressants and age

Antidepressants as a commodity have been remarkably little-studied by economists. This study shows in new data for 27 European countries that 8% of people (and 10% of those middle-aged) take antidepressants each year. The probability of antidepressant use is greatest among those who are middle-aged, female, unemployed, poorly educated, and divorced or separated. A hill-shaped age pattern is found. The adjusted probability of using antidepressants reaches a peak -- approximately doubling -- in people‟s late 40s. This finding is consistent with, and provides a new and independent form of corroboration of, recent claims in the research literature that human well-being follows a U-shape through life

International happiness

This paper describes the findings from a new, and intrinsically interdisciplinary, literature on happiness and human well-being. The paper focuses on international evidence. We report the patterns in modern data; we discuss what has been persuasively established and what has not; we suggest paths for future research. Looking ahead, our instinct is that this social-science research avenue will gradually merge with a related literature -- from the medical, epidemiological, and biological sciences -- on biomarkers and health. Nevertheless, we expect that intellectual convergence to happen slowly

Galaxy Formation Spanning Cosmic History

Over the past several decades, galaxy formation theory has met with significant successes. In order to test current theories thoroughly we require predictions for as yet unprobed regimes. To this end, we describe a new implementation of the Galform semi-analytic model of galaxy formation. Our motivation is the success of the model described by Bower et al. in explaining many aspects of galaxy formation. Despite this success, the Bower et al. model fails to match some observational constraints and certain aspects of its physical implementation are not as realistic as we would like. The model described in this work includes substantially updated physics, taking into account developments in our understanding over the past decade, and removes certain limiting assumptions made by this (and most other) semi-analytic models. This allows it to be exploited reliably in high-redshift and low mass regimes. Furthermore, we have performed an exhaustive search of model parameter space to find a particular set of model parameters which produce results in good agreement with a wide range of observational data (luminosity functions, galaxy sizes and dynamics, clustering, colours, metal content) over a wide range of redshifts. This model represents a solid basis on which to perform calculations of galaxy formation in as yet unprobed regimes.Comment: MNRAS accepted. Extended version (with additional figures and details of implementation) is available at http://www.galform.or

What makes an entrepreneur?

This article uses various micro data sets to study entrepreneurship. Consistent with the existence of capital constraints on potential entrepreneurs, the estimates imply that the probability of self-employment depends positively upon whether the individual ever received an inheritance or gift. When directly questioned in interview surveys, potential entrepreneurs say that raising capital is their principal problem. Consistent with our theoretical model's predictions, the self-employed report higher levels of job and life satisfaction than employees. Childhood psychological test scores, however, are not strongly correlated with later self-employment

Dark-matter decays and Milky Way satellite galaxies

We consider constraints on a phenomenological dark-matter model consisting of two nearly degenerate particle species using observed properties of the Milky Way satellite galaxy population. The two parameters of this model, assuming the particle masses are >~ GeV, are v_k, the recoil speed of the daughter particle, and tau, the lifetime of the parent particle. The satellite constraint that spans the widest range of v_k is the number of satellites that have a mass within 300 pc M300 > 5 x 10^6 solar masses, although constraints based on M300 in the classical dwarfs and the overall velocity function are competitive for v_k >~ 50 km/s. In general, we find that tau <~ 30 Gyr is ruled out for 20 km/s <~ v_k <~ 200 km/s, although we find that the limits on tau for fixed v_k can change constraints by a factor of ~3 depending on the star-formation histories of the satellites. We advocate using the distribution of M300 in Milky Way satellites determined by next-generation all-sky surveys and follow-up spectroscopy as a probe of dark-matter properties.Comment: 17 pages, 9 figures, submitted to Phys. Rev.

The Restructuring and Privatisation of British Rail: Was it really that bad?

Following the government�s decision to place Railtrack into administration (October 2001), attention has focused on what went wrong with privatisation, and how crucial network investment will be financed in future. This paper uses a social cost-benefit analysis framework to assess whether the restructuring and privatisation of British Rail has produced savings in operating costs. The paper shows that major efficiencies have been achieved, consumers have benefited through lower prices, whilst the increased government subsidy has been largely recouped through privatisation proceeds. We find that output quality has also improved (pre-Hatfield). The achievement of further savings will be key to delivering improved rail services in the future. This paper finds that a privatised structure, where shareholders demand a return on their investment, has led to significant improvements in operating efficiency - it remains to be seen whether the new regime, with a not-for-profit infrastructure owner, will deliver the same efficiency improvements

Hypotheses in Marketing Science: Literature Review and Publication Audit

We examined three approaches to research in marketing: exploratory hypotheses, dominant hypothesis, and competing hypotheses. Our review of empirical studies on scientific methodology suggests that the use of a single dominant hypothesis lacks objectivity relative to the use of exploratory and competing hypotheses approaches. We then conducted a publication audit of over 1,700 empirical papers in six leading marketing journals during 1984-1999. Of these, 74% used the dominant hypothesis approach, while 13 % used multiple competing hypotheses, and 13% were exploratory. Competing hypotheses were more commonly used for studying methods (25%) than models (17%) and phenomena (7%). Changes in the approach to hypotheses since 1984 have been modest; there was a slight decrease in the percentage of competing hypotheses to 11%, which is plained primarily by an increasing proportion of papers on phenomena. Of the studies based on hypothesis testing, only 11 % described the conditions under which the hypotheses would apply, and dominant hypotheses were below competing hypotheses in this regard. Marketing scientists differed substantially in their opinions about what types of studies should be published and what was published. On average, they did not think dominant hypotheses should be used as often as they were, and they underestimated their use