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991.
Assessment of Airborne Exposure to Trihalomethanes from Tap Water in Residential Showers and Baths 总被引:4,自引:0,他引:4
This study evaluates airborne concentrations of common trihalomethane (THM) compounds in bathrooms during showering and bathing in homes supplied with chlorinated tap water. Three homes in an urban area were selected, each having three bedrooms, a full bath, and approximately 1,000 square feet of living area. THMs were concurrently measured in tap water and air in the shower/bath enclosure and the bathroom vanity area using Summa canisters. Chloroform (TCM), bromodichloromethane (BDCM), and chlorodibromomethane (CDBM) were quantified using U.S. Environmental Protection Agency (EPA) Method TO-14. Air samples were collected prior to, during, and after the water-use event for 16 shower and 7 bath events. Flow rate and temperature were measured, but not controlled. The increase in average airborne concentration (+/- standard error) during showers (expressed as microg/m3 in shower enclosure or bathroom air per microg/L in water) was 3.3+/-0.4 for TCM, 1.8+/-0.3 for BDCM, and 0.5+/-0.1 for CDBM (n = 12), and during baths was 1.2+/-0.4 for TCM, 0.59+/-0.21 for BDCM, and 0.15+/-0.05 for CDBM (n = 4). The relative contribution of each chemical to the airborne concentrations was consistent for all shower and bath events, with apparent release of TCM > BDCM > CDBM. The results are therefore consistent with their relative concentration in tap water and their vapor pressures. When the shower findings for TCM are normalized for water concentration, flow rate, shower volume, and duration, the average exposure concentrations in these urban residences are about 30% lower than those reported by other investigators using EPA analytical methods. This difference is likely attributable primarily to greater air exchange rates in residential shower/bath stalls compared to more "airtight" laboratory shower chambers. This appears to be the first field study to thoroughly evaluate THM exposures from residential showers and baths, and can be used to validate previously published models of tap water volatile chemical transfer to indoor air. 相似文献
992.
Thomas C. Schelling 《Risk analysis》2000,20(6):833-838
A discount rate for the consumption of future generations is typically composed of two parts. One is a "pure" time preference for immediate over postponed consumption, the other a declining marginal utility as consumption increases. The costs of greenhouse abatement, however, for at least the first 50 years, will be borne by the developed countries; the benefits will accrue to the presently undeveloped. Pure time preference always relates to one's own consumption; it has no relevance here. Consumption transfers over time will be from richer to poorer, from lower to higher marginal utility. It is a foreign aid program and it ought to have to compete with more direct foreign aid, which can benefit the very poor rather than their much-better-off descendants. 相似文献
993.
This article introduces a special volume on misinformation about child sexual abuse. Despite extensive research findings on the long-term effects and consequences of child sexual abuse, misinformation on this topic is widespread. Several forces have worked to support and disseminate this erroneous information. Because it is difficult to comprehend the horror of sexual crimes against children, society's denial and disbelief have often unwittingly supported the agendas of those who want to discount or minimize the impact of these crimes. The media has also contributed to the aura of skepticism surrounding claims of sexual abuse and its mental health impact, and has reported favorably on controversial and unproven claims such as the false memory syndrome. In the hope of countering misinformation and thus raising the level of discourse to the engagement of real scientific issues, a number of well known and respected researchers and clinicians examine various facets of the problem. 相似文献
994.
OBJECTIVE: This pilot project assessed the effectiveness of an intervention to increase knowledge and reduce risky behaviors related to cumulative trauma disorders (CTD) in office workers. STUDY DESIGN: All 124 employees from the administrative offices of a health maintenance organization were invited to participate. Subjects were followed across time using an identification number. Data were collected via questionnaire in June 1994 (pretest1) (N=84), August 1994 (pretest II) (N= 63) and September 1995 (posttest) (N=40). The yearlong intervention focused on functional activities to prevent CTD. RESULTS: of chi-square analyses for the 40 subjects who completed all surveys indicated this intervention significantly increased overall knowledge of CTD (p =.002). Significant changes in self-reported hand/wrist (p =.016) and neck/shoulder (p =.003) posture were also found. CONCLUSIONS: This study is a first step in identifying effective educational interventions to increase knowledge and reduce risk factors related to CTD in office workers. 相似文献
995.
Chitsike C 《Gender and development》2000,8(1):71-77
This article identifies the important issues addressed by programs and projects that are aimed at promoting women's equality through entrepreneurship and suggests several actions for future focus of gender programs and training. Culture was seen as a barrier to the self-confident and autonomous economic activities of women in Zimbabwe. Likewise, structural barriers such as lack of marketable skills, time and ability to travel, land and assets, education, and position as primary family providers all compounded to the problem of entrepreneurship among women. Establishment of policy approaches for women like vocational skills training augmented by training in business skills and marketing, however, are insufficient since it failed to discuss and transfer behavioral skills necessary to make one an entrepreneur. To conclude, programs must be designed to empower personal skills and self-awareness, as well as address the constraints to entrepreneurship, and macroeconomic policy change. 相似文献
996.
Despite the substantial body of literature concerned with the ways in which digital media are transforming contemporary society and institutional life, we have relatively little understanding of the ways in which new technologies feature in day to day organizational conduct and interaction. There is however a growing corpus of empirical research which places the situated and contingent character of new technologies at the heart of the analytic agenda, but as yet, these studies are relatively little known within sociology. They include ethnographies of command and control centres, financial institutions, the news media, and the construction industry. They address the ways in which tools and technologies, ranging from paper documents through to complex multimedia systems, feature in work and collaboration. In this paper, we discuss these so-called 'workplace studies' and consider their implications for our understanding of organizational conduct, social interaction and new technology. 相似文献
997.
Berry C 《Journal of homosexuality》2000,39(3-4):187-200
This essay chooses as its texts three films representing contemporary gay male subjects from each of the "three" China's: HK, Taiwan, and the Mainland. Relocating the homoerotic image of the "sad young man," a trope popular from Hollywood rebellion films of the 1950s and 1960s, to contemporary China, I discuss how this masculine icon has been transformed from one of heroic rebellion to one of existential isolation. Indeed, as the politics of both the outmoded Confucian family and fractured Chinese nationhood intersect, what the sad young (gay) man rebels against is a political fluctuation which is no longer fixed; as the young man's opposition is no longer fixed, so too does he become alienated even from his own rebellious cause. 相似文献
998.
Effects of the Mechanism of Receptor-Mediated Gene Expression on the Shape of the Dose-Response Curve 总被引:1,自引:0,他引:1
A mathematical model of receptor-mediated gene expression that includes receptor binding of natural and xenobiotic ligands, protein synthesis and degradation, and metabolism of the xenobiotic ligand was created to identify the determinants of the shape of the dose-response profile. Values of the model's parameters were varied to reflect alternative mechanisms of expression of the protein. These assumptions had dramatic effects on the computed response to a bolus dose of the xenobiotic ligand. If all processes in the model exhibit hyperbolic kinetics, the dose-response curves can appear sigmoidal but actually be linear with a positive slope at low doses. The slope of the curve only approached zero at low dose, indicative of a threshold for response, if binding of the xenobiotic ligand to the receptor exhibited positive cooperativity (ligand binding at one site increases the affinity for ligand at another binding site on the receptor). Positive cooperativity in the rate-limiting step of protein synthesis produced dose-response curves which were "U-shaped" at low doses, also indicative of a threshold. Positive cooperativity in the metabolism of the xenobiotic ligand produced dose-response curves that increased more rapidly than linearly with increasing dose. The model illustrates the fact that response cannot be predicted from qualitative mechanistic arguments alone; any assessment of risk to health from xenobiotic chemicals must be based on a detailed quantitative examination of the kinetic behavior of each chemical species individually. 相似文献
999.
What Determines Trust in Information About Food-Related Risks? Underlying Psychological Constructs 总被引:12,自引:0,他引:12
Trust in risk information about food related-hazards may be an important determinant of public reactions to risk information. One of the central questions addressed by the risk communication literature is why some individuals and organizations are trusted as sources of risk information and others are not. Industry and government often lack public trust, whereas other sources (for example, consumer organizations, the quality media, medical doctors) are highly trusted. Problematically, previous surveys and questionnaire studies have utilized questions generated by the investigators themselves to assess public perceptions of trust in different sources. Furthermore, no account of the hazard domain was made. In the first study reported here, semistructured interviewing was used to elicit underpinning constructs determining trust and distrust in different sources providing food-related risk information ( n = 35). In the second study, the repertory grid method was used to elicit the terminology that respondents use to distinguish between different potential food-related information sources ( n = 35), the data being submitted to generalised Procrustes analysis. The results of the two studies were combined and validated in survey research ( n = 888) where factor analysis indicated that knowledge in itself does not lead to trust, but that trusted sources are seen to be characterised by multiple positive attributes. Contrary to previous research, complete freedom does not lead to trust—rather sources which possess moderate accountability are seen to be the most trusted. 相似文献
1000.
An environmental life cycle optimization model for the European pulp and paper industry 总被引:1,自引:0,他引:1
Will paper recycling reduce the environmental impact of the European pulp and paper sector? If so, is maximal paper recycling the best policy to optimize the life cycle of the pulp and paper sector? We explore these questions using an approach that combines materials accounting methods and optimization techniques. Environmental impact data are inputs for a linear programming network flow model to find optimal configurations for the sector. These configurations consist of a mix of different pulping technologies, a geographical distribution of pulp and paper production, and a level of recycling consistent with the lowest environmental impacts. We use the model to analyse scenarios with different recycling strategies. Recycling offers a reduction in environmental impact in regions with a high population and a large production of paper and board products. Regions with a large production of graphic products should focus on cleaner virgin pulp production with energy recovery. We conclude that relocation of paper production also offers a reduction in environmental impact. However, the severe effects on the economy make this policy less attractive than a combination of recycling, cleaner pulp production and energy recovery. 相似文献