A study of three-dimensional curves

In certain abnormalities of spinal shape, the long axis of the spine moves out of the median sagittal plane, producing both an axial torsion and a lateral deviation out of the usual front-back plane. Clinicians need to be able to assess rapidly and accurately whether or not an individual has such an abnormality. In this paper, we examine several case studies. These are analyzed using some simple summary statistics, and the use of these methods to infer abnormality is demonstrated. Using a simple fitted model for the data, an angular estimate of abnormality is obtained. Empirical measures of abnormality based on the eigenvalues of the covariance matrix are also determined. These methods are applied to a number of individuals for whom the surface spinal profiles have been recorded and who have been assessed as normal or abnormal by clinicians.     

Perfect samplers for mixtures of distributions

Summary. We consider the construction of perfect samplers for posterior distributions associated with mixtures of exponential families and conjugate priors, starting with a perfect slice sampler in the spirit of Mira and co-workers. The methods rely on a marginalization akin to Rao–Blackwellization and illustrate the duality principle of Diebolt and Robert. A first approximation embeds the finite support distribution on the latent variables within a continuous support distribution that is easier to simulate by slice sampling, but we later demonstrate that the approximation can be very poor. We conclude by showing that an alternative perfect sampler based on a single backward chain can be constructed. This alternative can handle much larger sample sizes than the slice sampler first proposed.     

Historical regional patterns of infant mortality in Austria

First an overview is given of the secular decline of infant mortality in Austria between 1820 and 1950 is given. Second the study analyses the historical regional differences of infant mortality in Austria comparing data for all 99 political districts (Politische Bezirke) for the period 1900 to 1950. The most important results are: At the turn of the 19th century infant mortality rates were generally lower in Alpine than in non-alpine regions and lower in cities than in their surrounding areas. This geographical pattern which remained constant until the 1950s was solely determined by differences in post-neonatal mortality rates. Plausible explanations for these regional differences are discussed.En premier lieu cette étude fournit une vue d'ensemble du déclin séculaire de la mortalité infantile en Autriche en 1820 et 1950. Elle analyse ensuite les différences régionales de mortalité infantile en comparant les données des 99 districts politiques (Politische Bezirke) autrichiens, de 1900 à 1950. Les principaux résultats sont les suivants: à la fin du XIX^e siècle les taux de mortalité infantile étaient en général plus faibles dans les régions alpines que dans les autres et plus faibles dans les villes que dans les aires adjacentes. Ce modèle géographique, qui est resté le même jusqu'en 1950, était uniquement déterminé par les différences entre les taux de mortalité post-néonatale. Des explications plausibles de ces différences régionales sont discutées ici.     

Do universal non‐contributory old‐age pensions make sense for rural areas in low‐income countries?

The need for old‐age security coverage in rural areas of many developing countries is rapidly increasing for several reasons, including population ageing and the weakening of family support networks. These trends have generated intense interest in policies that might help respond to the growing problem of rural old‐age destitution. The focus of our analysis is on one of the most promising alternatives under consideration: universal non‐contributory old‐age pensions. This model has some limitations and it is not appropriate for all developing countries, but it would be of potential benefit to far more than the six that have already implemented variants of this approach.     

Differentials in Adult Mortality and Activity Limitation by Years of Education in the United States at the End of the 1990s

This study examines mortality differentials and health disparities between educational groups within the 1998 adult population (ages 25 and older) in the United States. Mortality differentials are measured using average life expectancy and health disparities by expected years without activity limitation. The results indicate that for both sexes, higher education is associated with higher life expectancy. Those with higher levels of education also have higher life expectancy without activity limitation. Adults with higher education can also expect to enjoy a greater percentage of their expected lives free of any form of activity limitation. At each level of education, adult females have a higher level of activity limitation compared to adult males. At the same level of education, adult females expect to enjoy smaller percentages of their remaining lives free of activity limitation compared to adult males of the same age.     

Specialised Supported Education for Australians with Psychotic Disorders

Australia has a network of Federally funded disability employment and vocational rehabilitation services, including a proportion of outlets that specialise in providing services for persons with psychiatric disabilities. However, neither Federal nor State Governments currently provide or fund disability‐specific education assistance to persons with psychiatric disabilities. To begin considering whether Specialised Supported Education is indicated for persons with psychotic disorders, we examined data collected in a national ‘Survey of Disability, Ageing and Carers Australia, 1998’. International studies of the effectiveness of overseas Supported Education programs were also examined to identify the forms of assistance most likely to warrant consideration in Australia. U.S.A. evidence indicates that Specialised Supported Education is emerging as an effective career development option for persons with psychotic disorders. An example of an innovative Specialised Supported Education program is provided to illustrate how this type of program can be implemented in Australia.     

Stress Hormone Changes and Marital Conflict: Spouses’ Relative Power Makes a Difference

We investigated the impact of relative marital power on 72 newlywed couples’ endocrinological responses to marital conflict. Marital power was determined by comparing spouses’ reports of dependent love for one another. Less powerful spouses displayed elevated adrenocorticotropic hormone (ACTH) responses to a conflict discussion. Shared power appeared to have a beneficial effect on wives’ but not husbands’ ACTH responses. Spouses’ cortisol levels declined over time, except for wives who were less powerful and for husbands who shared power with their wives. Conflict behaviors did not differ as a function of this marital power index. These data suggest that relative levels of general emotional power in relationships may play an important role in spouses’ physiological responses to marital conflict.     

Now or Later?--Endogenous Timing of Threats

Whereas early threats are chosen before bargaining, late threats are determined after bargaining ended in conflict. Instead of exogenously imposing the timing of threats, these are derived endogenously as in indirect evolution or endogenous timing. Based on a duopoly market, we first derive the equilibrium for all possible constellations regarding the timing of threats. Our analysis surprisingly justifies the early timing of threats as suggested by Nash (1953).     

CURBSIDE RECYCLING IN THE PRESENCE OF ALTERNATIVES

We measure the extent to which curbside access affects quantity recycled. We use novel data to distinguish between new recycling and material diverted from other recycling modes. We find that the marginal impact of expanding curbside programs on total recycled quantities is small, in part because curbside programs significantly cannibalize returns from drop-off recycling centers. Failure to account for cannibalization from other modes may substantially overestimate the benefits of curbside programs. We conclude with simple cost-effectiveness comparisons. Results suggest that incremental expansion of curbside access may not be cost-effective. ( JEL Q53, Q58, H72)