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731.
732.
To answer the question whether a negative result of gas chromatographic blood analysis for components of chemical mace proves that no or at most only slight tear gas exposure can have occurred, animal experiments were carried out. In the blood of 10 guinea pigs, which were exposed to the contents of chemical mace for 1--6 h, the solvants 1,1,2-trichloro-1,2,2-trifluorethane (freon 113) and 1,1,1-trichloroethane could easily be detected--even 23 h after the end of exposure or after a storage of the blood samples for 18 weeks--whereas the lacrimator chloracetophenone (CN) could not be found at all. In vitro experiments showed that CN relatively quickly reacts with components of blood. Therefore, blood samples should be analyzed for CN after withdrawal as soon as possible. In case of inhalation of the contents of chemical mace, i.e., after the comparatively mildest form of CN application, most probably no traces of the lacrimator at all can pass into the blood due to the quick reaction of CN with proteins of the respiratory surface of the lung. 相似文献
733.
734.
Reasons for sub-Saharan Africa's development deficit that the commission for Africa did not consider
Despite a substantial amount of aid (much larger in per capitaterms than provided to any other region), sub-Saharan Africancountries, with very few exceptions, have regressed since independence.The general history of Africa since achieving independence hasbeen one of development failure. Some protagonists point tosigns of change that argue for more aid. This article suggeststhat aid to Africa has not worked because human, social andinstitutional capital not financial capital poses the binding constraint. In that context, doubling aidto Africa from $23 billion in 2004 to $50 billion annually by2015 seems a questionable proposition. This commentary suggestsunconventional ways of dealing with the problems involved inimporting the essential ingredients that Africa needs. It concludeswith the observation that the aid communitys currentobsession with poverty reduction and the Millennium DevelopmentGoals (MDGs) may be harming rather than helping the cause ofdevelopment in Africa and argues that the focus on growth anddevelopment should be restored. 相似文献
735.
The authors investigated the dimensions and mechanisms of belonging relevant to motivation and achievement among high school students representing 4 ethnic groups. Using survey data from 9th to 12th grade students (N = 5,494) attending 7 ethnically-diverse high schools, structural equation modeling was employed to explore, independently for each ethnic group, the relationships between students’ perceptions of their belonging (encompassing relationships with teachers and peers, extracurricular involvement, and perceived ethnic-based discrimination), motivation (efficacy beliefs and valuing school activities), and academic success. All 4 measures of belonging were significant for European-American and Latino students. However, friendship nominations were not significant for all groups, suggesting potential variability in perspectives across ethnic groups. The strength of the structural model postulating belonging as a mediator, including statistically significant indirect paths, supported the hypothesis that the belonging construct accounted for much of the relationship between student motivation and success across groups.Beverly Faircloth is a doctoral candidate of the University of North Carolina at Chapel Hill. Her research interests include the developmental and motivational processes that support adolescent school engagement in ethnically diverse settings.Jill Hamm is an Assistant Professor at the University of North Carolina at Chapel Hill. She received her Ph.D. from the University of Wisconsin-Madison in 1996. Her research interests are adolescents’ peer relations in ethnically diverse schools and classrooms. 相似文献
736.
Jennifer?A.?FredricksEmail author Jacquelynne?S.?Eccles 《Journal of youth and adolescence》2005,34(6):507-520
In this article, we test: (a) the relation between school-based extracurricular participation and indicators of positive and
negative development across a range of activity contexts, and (b) a mediation model linking activity participation, prosocial
peers, and development. Extensive survey information was collected from a predominately White sample of middle class adolescents
in 9th, 10th, and 12th grades. Extracurricular participation was related to more favorable academic, psychological, and behavioral
adjustment; the pattern of findings differed by activity and outcome. In addition, we documented some support for the hypothesis
that the link between extracurricular participation and positive adjustment is partly a function of associating with a prosocial
peer group. Implications of these findings and suggestions for future research are presented.
Assistant Professor of Human Development, Connecticut College. Received her PhD in 1999 from the University of Michigan. Major
research interests include motivation, school engagement, extracurricular participation, and adolescent development.
MacKeachie Collegiate Psychology Professor, University of Michigan. Received PhD in 1974 from the UCLA. Recent work focuses
on ethnicity and the transitions from middle childhood to adolescence and into adulthood. 相似文献
737.
This ecological study examined the association between seven socioeconomic indicators (GDP, unemployment rate, female labor force participation rate, alcohol expenditure, marriage rate, percentage of births outside of marriage, and indictable crime rate) and total, male, and female rates of suicide and suicide plus undetermined death in Ireland during the period 1968-2000. Analysis of the data expressed as absolute values showed highly significant associations between the socioeconomic indicators and the total, male, and female suicide rates. However, these associations were explained by the strongly trended data. The trended nature of the data was removed by using year-to-year differences. Analysis of the first-differenced data showed that none of the socioeconomic indicators was associated with the total, male, or female suicide rates with the exception of indictable crime, which had a significant independent effect on the female suicide rate (coefficient = 2.0, p < .01) but not on suicide plus undetermined death. This study highlights the need to use econometric methods in time-trend analyses, the lack of age-sex specific exposure data in this area, and the challenge of understanding trends in suicide in their socioeconomic context. 相似文献
738.
In a second test of an arthropod saturation hypothesis, we analyzed if the on-campus Anthropology Research Facility (ARF) at the University of Tennessee, Knoxville, with its 20+ yr history of carcass enrichment, is comparable to non-enriched sites in community structure of predatory and parasitic arthropods that prey upon the sarcosaprophagous fauna. Over a 12-day period in June 1998, using pitfall traps and sweep nets, 10,065 predaceous, parasitic, and hematophagous (blood-feeding) arthropods were collected from freshly euthanized pigs (Sus scrofa L.) placed at ARF and at three surrounding sites various distances away (S2-S4). The community structure of these organisms was comparable in most paired-site tests with respect to species composition, colonization rates, and evenness of pitfall-trap abundances on a per carcass basis. Site differences were found in rarefaction tests of both sweep-net and pitfall-trap taxa and in tests of taxonomic evenness and ranked abundances of sweep-net samples. Despite these differences, no evidence was found that the predatory/parasitic fauna at ARF was impoverished with fewer but larger populations as a result of carcass enrichment. Comparison of the sarcosaprophagous and predatory/parasitic faunas revealed a tighter (and more predictable) linkage between carrion feeders (sarcosaprovores) and their carrion than between carrion feeders and their natural enemies (predators and parasitoids), leading us to conclude that ARF is more representative of surrounding sites with respect to the sarcosaprovore component than to the predatory/parasitic component within the larger carrion-arthropod community. 相似文献
739.
740.
Sípoli Marques MA Pinto Damasceno LM Gualberto Pereira HM Caldeira CM Pereira Dias BF de Giacomo Vargens D Amoedo ND Volkweis RO Volkweis Viana RO Rumjanek FD Aquino Neto FR 《Journal of forensic sciences》2005,50(3):587-592
A clear positive case for anabolic steroids doping was confounded by alleged urine tampering during doping control procedures. Review of the chain of custody showed no flaws, but nevertheless the athlete was adamant that the urine sample should be analyzed for DNA in order to support her contention that she was not the donor of the sample. The results obtained showed that the urine sample that scored positive for steroids contained nuclear DNA that could not be matched to the DNA obtained from the athlete's blood. On the other hand, the same urine sample contained mitochondrial DNA whose nucleotide sequences spanning the hyper variable regions HV1 and HV2 proved to be identical to those determined in mitochondrial DNA amplified from the athlete's blood. The occurrence of an extraneous genotype is compatible with exogenous nuclear DNA admixture to the athlete's urine. Alternatively, taking in consideration the mitochondrial DNA, we could not exclude that a sibling or a maternal relative of the athlete could have acted as a donor of the urine utilized for doping control and DNA analysis. Both situations point to possible tampering of the urine by the athlete. Adjudication at CAS maintained previous national and international federation decision that there was no proof of a chain of custody flaw to justify the athlete's allegation of urine substitution after collection. 相似文献