An alternative estimator for multiple characteristics in PPS sampling

The problem considered relates to large-scale sample surveys. A new estimator of population total for the characteristics that are poorly correlated with the selection probabilities has been developed for the PPSWR sampling scheme. The relative efficiency of the proposed estimator has been studied under a super-population model. A numerical investigation into the performance of the estimator has also been made.     

Exposure Reconstruction for the TCDD-Exposed NIOSH Cohort Using a Concentration- and Age-Dependent Model of Elimination

Recent studies demonstrating a concentration dependence of elimination of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) suggest that previous estimates of exposure for occupationally exposed cohorts may have underestimated actual exposure, resulting in a potential overestimate of the carcinogenic potency of TCDD in humans based on the mortality data for these cohorts. Using a database on U.S. chemical manufacturing workers potentially exposed to TCDD compiled by the National Institute for Occupational Safety and Health (NIOSH), we evaluated the impact of using a concentration- and age-dependent elimination model (CADM) (Aylward et al., 2005) on estimates of serum lipid area under the curve (AUC) for the NIOSH cohort. These data were used previously by Steenland et al. (2001) in combination with a first-order elimination model with an 8.7-year half-life to estimate cumulative serum lipid concentration (equivalent to AUC) for these workers for use in cancer dose-response assessment. Serum lipid TCDD measurements taken in 1988 for a subset of the cohort were combined with the NIOSH job exposure matrix and work histories to estimate dose rates per unit of exposure score. We evaluated the effect of choices in regression model (regression on untransformed vs. ln-transformed data and inclusion of a nonzero regression intercept) as well as the impact of choices of elimination models and parameters on estimated AUCs for the cohort. Central estimates for dose rate parameters derived from the serum-sampled subcohort were applied with the elimination models to time-specific exposure scores for the entire cohort to generate AUC estimates for all cohort members. Use of the CADM resulted in improved model fits to the serum sampling data compared to the first-order models. Dose rates varied by a factor of 50 among different combinations of elimination model, parameter sets, and regression models. Use of a CADM results in increases of up to five-fold in AUC estimates for the more highly exposed members of the cohort compared to estimates obtained using the first-order model with 8.7-year half-life. This degree of variation in the AUC estimates for this cohort would affect substantially the cancer potency estimates derived from the mortality data from this cohort. Such variability and uncertainty in the reconstructed serum lipid AUC estimates for this cohort, depending on elimination model, parameter set, and regression model, have not been described previously and are critical components in evaluating the dose-response data from the occupationally exposed populations.     

Introduction Private and Public: Gender,Generation and Family Life in Flux

In the past four decades, Hong Kong has seen a dramatic transformation of the social location of women in the public sphere, with deep and far-reaching ramifications for courtship, marriage, fertility, conceptions of parenthood, familial power, and equality and freedom. A sociology of the family is thus by necessity a sociology of women in particular, and of gender relations in general. Indeed, recent developments in research on marriage and the family in Hong Kong reflect this new awareness. Using rigorous sociological frameworks, this new line of research has begun to meet with some success in analyzing contemporary social issues that are prominent in the public consciousness. This essay reviews studies of four topical areas: determinants of the postponement of first marriage among women, the effect of live-in foreign domestic workers on family dynamics, violence against women and children in the family, and the livelihood strategies of cross-border families. These studies have attempted to integrate the interplay of the impact of a changing economy and society on the family and the role played by women in the family. The resulting dynamic interactions amongst the members within the family and the changes they bring about become propellants for change in the economy and society and pose new challenges. The family is indeed a troubled institution. It is so because myriad public issues are being taken on, confronted, worked through, and acted out within the family. The agony, and indeed the ecstasy, of the family is a reflection of the success, and failure, of society.     

Haarige Helfer,gefiederte Gefährten und schuppige Freunde

Pets are not only family members. For a lot of people in all stages of life cycle, pets are important sources of support. They are able to contribute to our health as well as to buffer stress and illness in our lives. The may be seen as important agents of socialisation and development of children and as friendly companions of the elderly. The article reviews the state of knowledge in positive aspects of human animal bonds and develops a bio-psycho-social panorama of effects.