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.     

多平台CAI课件的开发技术

简要介绍了多媒体CAI课件的开发工具,阐述了基于多平台开发CAI课件的方法,针对微机测控技术、现代仪表技术、电工技术等不同的授课内容,选择不同的CAI开发平台,文章介绍了POWERPOINT中嵌入PSPICE仿真工具、用FLASH进行课堂演示实验的经验,并以POWERPOINT为例,说明了多平台开发CAI课件的具体应用.     

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.     

多维互动:族际政治整合机制研究

多维互动是族际政治整合的一种重要机制,政府、社会组织、族员三者互动的结构、特点、方式、内容构成了这种机制的基本框架。其具有认知、理解、信任、包容等功能,这些功能促进了各族员由民族认同到国家认同的转向。因此,建构族际政治整合多维互动机制是实现各族员和谐共处、共同发展的政治保障。     

有利砂体识别与解释

天然气的产量与砂岩的厚度,孔隙度,连通性,砂泥比等有密切的关系。为了解决砂体在空间以什么形态出现,其方向如何,纵向上如何变化,连通形式如何等问题,在前人研究的基础上,对篷来镇组某工区的砂体进行了精细识别和解释。在地震剖面上,砂体的响应一般表现为强振幅,低频率。孔隙性好,含气丰度高的砂体往往表现为速度低和极性反转的特点。但发现该工区的砂体在地震剖面上表现形式多变,甚至出现了合成地震记录与井旁地震记录严重不吻合的现象,故砂体识别工作不能遵循统一模式。因此,采用了多井约束,多层标定,分层解释来识别有利砂体。     

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.