Consideration of Background Exposures in the Management of Hazardous Waste Sites: A New Approach to Risk Assessment

The current approach to health risk assessment of toxic waste sites in the U.S. may lead to considerable expenditure of resources without any meaningful reduction in population exposure. Risk assessment methods used generally ignore background exposures and consider only incremental risk estimates for maximally exposed individuals. Such risk estimates do not address true public health risks to which background exposures also contribute. The purpose of this paper is to recommend a new approach to risk assessment and risk management concerning toxic waste sites. Under this new approach, which we have called public health risk assessment, chemical substances would be classified into a level of concern based on the potential health risks associated with typical national and regional background exposures. Site assessment would then be based on the level of concern for the particular pollutants involved and the potential contribution of site contaminants to typical background human exposures. While various problems can be foreseen with this approach, the key advantage is that resources would be allocated to reduce the most important sources of human exposure, and site remediation decisions could be simplified by focussing on exposure assessment rather than questionable risk extrapolations.     

《林四娘》故事源流补考

林四娘的故事在康熙年间盛传一时，新发现的陈奕禧作品《林四娘小传》与蒲松龄、王士棋、李澄中等山东作家的记载相比，差距较大，与林云铭记述的故事更接近。若想了解这个有关青州衡王府宫人故事的文化背景，应该关注与她的名字密切联系的陈宝钥。陈宝钥是福建晋江人，曾参加了南明抗清斗争，又是一位多产的诗人。林四娘应该是陈宝钥部署的代言人，陈宝钥用自己和林四娘的唱和来抒发他的亡国之思。     

Rural-urban residence and modernism: A study of Ankara Province,Turkey

Data from the Ankara Family Study, in which 1138 married women living in Ankara city and four selected villages in Ankara Province were interviewed in 1965–66, are used to study the impact of the amount and timing of urban residential experience on six dimensions of modernism in attitudes and behavior. Scores on the modernism indexes consistently are higher for the women with urban residential experience. The proportions of variance in the study population accounted for by the urbanism factor are: nearly three-fifths on the mass media index; nearly two-fifths on the nuclear family role structure index; three-tenths on the home production or consumption index; two-tenths on the religiosity and extra-local orientation indexes; and a seventh on the extended family ties index. The place of residence prior to marriage, the period when decisions about schooling are made and socialization into adult roles occurs, appears to be of special importance. Women who migrated from villages to the city at any stage of the life-cycle, however, report attitudes and behavior more modern than those of women with no urban residential experience (though less modern than those of women who have always lived in a city). Such micro-social analyses may help to illuminate the relation between urbanization and modernization in developing nations and to account for the coexistence of modern and traditional patterns in transitional societies.     

Four eras of study of college student suicide in the United States: 1920-2004

Studies of college student suicide can be grouped into the following 4 eras: 1920-1960, 1960-1980, 1980-1990, and 1990-2004. The suicide rate for students has declined monotonically across these 4 eras, from 13.4 to 8.0 to 7.5 and, most recently, to 6.5. The decreasing proportion of men in the student populations studied largely accounts for this decline. Since 1960, the suicide rate for students has consistently been about half the rate of the general US population, matched for age and gender. This highly favorable relative suicide rate is the result of firearms having been effectively banned from campuses. Additional population-oriented approaches warrant implementation to further reduce student-suicide rates. Approaches focused on high-risk groups also hold promise. These findings are based upon and may be most valid for the 70% of all students who attend 4-year colleges and universities full time.     

A simple alternative to the likelihood ratio test in a logistic discrimination problem

We consider the problem of hypothesis-testing under a logistic model with two dichotomous independent variables. In particular, we consider the case in which the coefficients β₁, and β₂ of these variables are known on an a priori basis to not be of opposite sign. For this situation we show that there exists a simple nonparametric altenative to the likelihood ratio test for testing H₀: β₁ = β₂ = 0 VS.H₁ at least one β₁ = 0. We find the asympotic relative efficiency of this test and show that it exceeds 0.90 under a wide range of conditions. We also given an example.     

Definitions of Need: Can disabled people and care professionals agree?

This paper attempts to examine the ideological frames of reference that inform the definitions of need that are used by disabled and non-disabled people. The main aim of the research upon which this paper is based being to test the degree of congruence of the non-disableds view of need with that of disabled people. Central to this is an exploration of the differences that exist in the perception of disability held by disabled people and nondisabled people. It investigates this through the use of a staged vignette based around a fictitious character (Mr Arthur Angus) and his family. The paper seeks to explore the multidimensional contexts in which individuals operate based upon a deconstruction of the medical/social locus of control model.     

Priority algorithms for the subset-sum problem

Greedy algorithms are simple, but their relative power is not well understood. The priority framework (Borodin et al. in Algorithmica 37:295–326, 2003) captures a key notion of “greediness” in the sense that it processes (in some locally optimal manner) one data item at a time, depending on and only on the current knowledge of the input. This algorithmic model provides a tool to assess the computational power and limitations of greedy algorithms, especially in terms of their approximability. In this paper, we study priority algorithm approximation ratios for the Subset-Sum Problem, focusing on the power of revocable decisions, for which the accepted data items can be later rejected to maintain the feasibility of the solution. We first provide a tight bound of α≈0.657 for irrevocable priority algorithms. We then show that the approximation ratio of fixed order revocable priority algorithms is between β≈0.780 and γ≈0.852, and the ratio of adaptive order revocable priority algorithms is between 0.8 and δ≈0.893. A preliminary version of this paper appeared in the Proceedings of COCOON 2007, LNCS 4598, pp. 504–514.