A class of symmetric bivariate uniform distributions

A class of symmetric bivariate uniform distributions is proposed for use in statistical modeling. The distributions may be constructed to be absolutely continuous with correlations as close to±1 as desired. Expressions for the correlations, regressions and copulas are found. An extension to three dimensions is proposed.     

Useful relationship between the log-survival function and truncated moments,with applications

We present a new characterization technique extracted from a well known idea in statistical inference. We use the partial derivative of the logarithm of the survival function in connection with truncated moments to characterize several probability distributions. Our methods introduce a unified technique to obtain several well known results in a unified way.     

EXAMINING THE WAGE DIFFERENTIAL FOR MARRIED AND COHABITING MEN

Wage analyses indicate that married and cohabiting men earn more than do single, noncohabiting men. This article examines the nature of these wage differentials using data from the National Survey of Families and Households. Results indicate that the marital and cohabitation differentials are quite distinct. The higher wage observed for cohabiting men is driven primarily by selection and is eliminated by first differencing, but the higher wage observed for married men (and perhaps long-term cohabiters) arises largely because of differential wage growth. Wages appear to rise more rapidly following marriage.     

An Interview with Joyce Edward: Exemplary Clinician, Advocate, and Scholar

Over the years, noteworthy social workers have been interviewed for the Clinical Social Work Journal. This article features an interview with Joyce Edward who is recognized for her many extraordinary contributions to clinical social work. Joyce has co-written or co-edited three exceptional books for the social work clinician, she has been an esteemed teacher and a vocal activist for quality mental health care. In this interview Joyce reflects on family influences, her work as a social caseworker, the psychoanalytic luminaries with whom she trained, her concerns about the clinical education of today's social work students, and finally, her perspective on managed mental health care.     

TOOLS OR TOYS? THE IMPACT OF HIGH TECHNOLOGY ON SCHOLARLY PRODUCTIVITY

We examine the impact of communication technology on scholarly productivity by considering patterns of coauthored economics articles. Using articles in three major economics journals from 1970–79 and 1992–96, we find (1) sharp growth from distant coauthorships (authors not in the same metropolitan area prior to publication), as the theory predicts, and, contrary to theory, (2) lower productivity of distant than close-coauthored works and no decline in their relative disadvantage. These findings are reconciled by noting that high technology has aspects of a consumer good. The relative productivity of solo-authored articles has decreased, perhaps explaining the secular increase in coauthorship.     

The University: An Agent of Social Change?

Can universities be agents of progressive social change? How would we know if a university was acting as an agent of social change? Drawing on four case studies, I raise a number of questions to problematize our understanding of the university as an agent of social change. I outline a number of contributing factors that appear to explain successful cases. I conclude by arguing the relevancy of these cases for larger, and more traditional, sociological projects.     

Fire and restoration of the largest urban forest of the world in Rio de Janeiro City,Brazil

National Park of Tijuca in Rio de Janeiro (Brazil) is about 3,300 ha and considered the largest urban forest in the world. Its floristic composition is typical of Atlantic Rain Forest. The reserve is being altered because of fire occurrences and urban expansion. This study identified locations and causes of forest fires, and makes management recommendations to restore damaged areas. From 1991 to 2000, forest firefighters recorded an average of 75-fire occurrences/year. Identified causes included hot air balloons (24%), intentional (24%), rubbish burning (21%) and religious practices (17%). Primary fuels included invasive grasses and ferns. Although hot air balloons destroyed larger areas of forest in each occurrence, a greater number of fires started in the invasive vegetation along roads that bisect the forest. In response to recurrent forests, invasive vegetation has spread gradually into the forest increasing forest degradation. To decrease fire damage, sites with high fire frequencies and density of invasive vegetation were planted with less flammable species. Results indicate that fire frequency decreased and density of invasive vegetation declined. This approach appears to prevent fire incidence, reduce the need for fire fighting, and preserve existing biodiversity.     

Design optimization using ANOVA

This paper describes the design optimization of a robot sensor used for locating 3-D objects employing the Taguchi method in a computer simulation scenario. The location information from the sensor is to be utilized to control the movements of an industrial robot in a 'pick-and-place' or assembly operation. The Taguchi method, which is based on the Analysis-of-Variance (ANOVA) approach, is utilized to improve the performance of the sensor over a wider operating range. A review of the Taguchi method is presented along with step-by-step implementation details to identify and optimize the design parameters of the sensor. The method allows us to gauge the impact of various interactions present in the sensor system exclusively and permits us to single out those factors that have a dominant influence on the overall performance of the sensor. The investigation suggests that the Taguchi method is a more structured and efficient approach for achieving a robust design compared with the classical full factorial design approach.     

Still-births among the offspring of male radiation workers at the Sellafield nuclear reprocessing plant: detailed results and statistical aspects

Summary. This study investigates whether there was evidence of increasing risk of still-birth with increasing paternal exposure to ionizing radiation received during employment at the Sellafield nuclear installation before the child was conceived. A significant positive association is found between the total paternal preconceptional exposure to external ionizing radiation and the risk of still-birth (after adjustment for year of birth, social class, birth order and paternal age, odds ratio at 100 mSv 1.24 (95% confidence interval 1.04–1.45)). A summary of the principal scientific findings of this study has been published in the Lancet . This paper describes in detail the statistical methods that were used in the investigation and presents the results in full.