A general inverse sampling scheme and its application to adaptive cluster sampling

Not having a variance estimator is a seriously weak point of a sampling design from a practical perspective. This paper provides unbiased variance estimators for several sampling designs based on inverse sampling, both with and without an adaptive component. It proposes a new design, which is called the general inverse sampling design, that avoids sampling an infeasibly large number of units. The paper provide estimators for this design as well as its adaptive modification. A simple artificial example is used to demonstrate the computations. The adaptive and non‐adaptive designs are compared using simulations based on real data sets. The results indicate that, for appropriate populations, the adaptive version can have a substantial variance reduction compared with the non‐adaptive version. Also, adaptive general inverse sampling with a limitation on the initial sample size has a greater variance reduction than without the limitation.     

Theoretical consideration of effect of fishing mortality on growth and reproduction of fish populations

Summary An increase in fish mortality due to fishing can theoretically change the growth and reproduction of fish populations from the viewpoint of adaptation. We address the issue of how an iteroparous fish should convert surplus energy into somatic growth and reproduction at each age under given conditions of mortality. A model of life history, which maximizes the net reproductive rate using the discrete maximum principle, is improved employing a new relationship between body weight and surplus energy which we have recently proposed. The model is applied to the North Sea plaicePleuronectes platessa, for which it has been reported that the average length of young fish had increased whereas that of old ones had decreased for some decades. Although the model cannot directly explain the former phenomenon, the two phenomena can be interpreted as a change in the optimal life history due mainly to an increase in mortality.     

American Indian/Alaska Native Elders: A Growing Demographic that Is Changing How We View Aging

Today, AIAN Elders are more actively engaged in their families and communities, encouraging the development of intergenerational programs, language and cultural revitalization, being stewards in research conducted in their communities, as well passing on their knowledge and experiences on how to live as healthy Native people. Elders have traditionally been quiet and observant of their environment, but the current and future cohorts of Elders are advocates, leaders, and culture bearers for their families and communities and they are now in positions of leadership. Western society acknowledges the value of traditional knowledge and AIAN Elders are viewed as exemplars of healthy aging and their lessons and experiences can be attributed to our own lives. This commentary highlights the paradigm shift in how society views older adults, specifically AIAN Elders and their role in health and wellbeing.     

Housing hardship and energy insecurity among native-born and immigrant low-income families with children in the United States

The costs for rent and utilities account for the largest share of living expenses, yet these two critical dimensions of material hardship have seldom been examined concurrently in population-based studies. This paper employs multivariate statistical analysis using American Community Survey data to demonstrate the relative risk ratio of low-income renter-occupied households with children experiencing ‘rent burden', ‘energy insecurity', or a ‘double burden’ as opposed to no burden. Findings suggest that low-income households are more likely to experience these economic hardships in general but that specific groups are disproportionately burdened in different ways. For instance, whereas immigrants are more likely to experience rental burden, they are less likely to experience energy insecurity and are also spared from the double burden. In contrast, native-born African Americans are more likely than all other groups to experience the double burden. These results may be driven by the housing stock available to certain groups due to racial residential segregation, decisions regarding the quality of housing low-income householders are able to afford, as well as home-country values, such as modest living and energy conservation practices, among immigrant families. This paper also points to important policy gaps in safety net benefits related to housing and energy targeting low-income households.     

Towards a Model of Working Groups

No abstract available for this article.     

Intimate Violence in Lesbian Relationships

This paper describes the findings of a survey of 1109 lesbians who attended the Women's Music Festival held in Michigan in carly August 1985. The primary objectives of the study were to document the incidence of domestic violence in a non-random sample of lesbian relationships; to identify and describe the types of domestic violence experienced and/or perpetrated; and to ascertain thc availability and accessibility of community helping resources to survivors and perpetrators after an abusive episode. Comparisons with domestic violence in heterosexual relationships are also made, followed by a discussion on the research and practice implications of the findings.     

Dual experiences of teenage parenting and homelessness among Native Hawaiian youth: A critical interpretative phenomenological analysis

Teenage parenting is a challenging venture—particularly when parenting while homeless. The present study explores in‐depth through case‐based analysis the lived experiences of three young homeless and parenting teens (one mother and two fathers). It is the first known study of teenage parenting and homelessness among Native Hawaiian youth, a key affected population. Interpretative phenomenological analysis of participants' individual interviews revealed three themes that characterize the experience of parenting as a teen while homeless: (a) They never raised me up (childhood experiences); (b) becoming mommy and daddy (early experiences of teen pregnancy and parenting while homeless); and (c) finding our place (current experiences of teen parenting and perspectives on teen pregnancy and homelessness). Implications for direct practice, social policy, and future research are discussed in the context of this complex reality.     

THE USE OF AGGREGATE DATA TO ESTIMATE GOMPERTZ‐TYPE OLD‐AGE MORTALITY IN HETEROGENEOUS POPULATIONS

We consider two related aspects of the study of old‐age mortality. One is the estimation of a parameterized hazard function from grouped data, and the other is its possible deceleration at extreme old age owing to heterogeneity described by a mixture of distinct sub‐populations. The first is treated by half of a logistic transform, which is known to be free of discretization bias at older ages, and also preserves the increasing slope of the log hazard in the Gompertz case. It is assumed that data are available in the form published by official statistical agencies, that is, as aggregated frequencies in discrete time. Local polynomial modelling and weighted least squares are applied to cause‐of‐death mortality counts. The second, related, problem is to discover what conditions are necessary for population mortality to exhibit deceleration for a mixture of Gompertz sub‐populations. The general problem remains open but, in the case of three groups, we demonstrate that heterogeneity may be such that it is possible for a population to show decelerating mortality and then return to a Gompertz‐like increase at a later age. This implies that there are situations, depending on the extent of heterogeneity, in which there is at least one age interval in which the hazard function decreases before increasing again.     

乌梁素海鱼类寄生虫调查初步报告

本文首次报道了乌梁素海鱼类寄生虫13种,隶属8目11科11属.对乌梁素海鱼类寄生虫的区系组成有了初步了解,为今后鱼病的防治提供了依据和建议.     

A social welfare perspective of market‐oriented social enterprises

The article analyses market‐oriented social enterprises from a social welfare perspective, within the context of the innate conflict between business and welfare orientations. After defining the concept of market‐oriented social enterprises and presenting some successful examples on such entities that employ different marginalised populations, particularly people with disabilities, the article asks three interrelated questions: (i) What policy environment is needed to encourage the development of social enterprises? (ii) Given the innate tension between the social and economic objectives in social enterprises, what structural principles are needed to enable them to meet those dual objectives? Lastly, (iii) What intervention modalities are best suited to help individual participants in those frameworks? Answers to these questions are discussed within conceptual frameworks from the worlds of welfare and business that jointly provide a base for a social welfare rationale for market‐oriented social enterprises.