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101.
Validation of a 16-locus fluorescent multiplex system   总被引:24,自引:0,他引:24  
STR multiplexes have been indispensable for the efficient genotyping of forensic samples. The PowerPlex 16 System contains the coreCODIS loci, D3S1358, D5S818, D7S820, D8S1179, D13S317, D16S539, D18S51, D21S11, CSF1PO, FGA, THOI, TPOX, vWA, the sex determinant locus, amelogenin, and two pentanucleotide STR loci, Penta D and Penta E. This multiplex satisfies the locus requirements for most national databases and is the most efficient currently available system due to its single PCR amplification. To provide the groundwork for judicial acceptance, including the publication of primer sequences, and to evaluate laboratory-to-laboratory variation, a developmental validation for casework on this commercially available system was performed in 24 laboratories and produced the following conclusions. Amplification was reliable on a variety of thermal cyclers and product could be analyzed on either an ABI PRISM 310 Genetic Analyzer or an ABI PRISM 377 DNA Sequencer. Genotyping using single source samples was consistent between 0.25 and 2 ng of input DNA template with a few laboratories obtaining complete genotypes at 0.0625 ng. However, heterozygote allele imbalance (<60% peak height balance) caused by stochastic effects was observed at a rate of 13% with 0.125 ng DNA and 22% at 0.0625 ng DNA. Mixture analyses were done using a total of 1 ng of DNA template. Most alleles were detected in mixtures of 4 to 1 and some minor alleles were detected in mixtures of 19 to 1. Optimum amplification cycle number was dependent on the sensitivity of the detection instrument used and could also be adjusted to accommodate larger amounts of DNA on solid supports such as FTA paper. Reaction conditions including volume, annealing temperature, and concentrations of primer, AmpliTaq Gold, and magnesium were shown to be optimal yet robust enough to withstand moderate variations without affecting genotype analysis. Environmental, matrix and standard source analyses revealed an ability to obtain complete genotypes in all sample types except those exposed to 80 degrees C for 12-48 days. Finally, comparison of genotype results from the PowerPlex 16 System with other commercially available systems on non-probative reference and forensic samples showed consistent results.  相似文献   
102.
To what extent do local government Web sites support practical, meaningful public involvement? Fifteen years after the adoption and diffusion of the World Wide Web, the answer to this question remains cloudy and controversial. The promise—and peril—of Web‐based public involvement, known as e‐democracy, has been widely debated. Much of the debate has focused on theoretical abstractions or extrapolations of current political or technological trends. Empirical studies have been limited to reports on pilot projects, case studies, or special population surveys. This paper contributes to our empirical understanding of the question. It reports results of a recent comprehensive survey of official government Web sites in the principal cities of the 100 largest U.S. metropolitan areas. In particular, it examines whether and how U.S. city government Web sites facilitate users’ involvement in local public issues.  相似文献   
103.
We elucidate a powerful yet simple method for deriving comparative statics conclusions for a wide variety of models: Monotone Comparative Statics ( Milgrom and Shannon 1994 ). Monotone comparative static methods allow researchers to extract robust, substantive empirical implications from formal models that can be tested using ordinal data and simple nonparametric tests. When these methods apply, they can replace a diverse range of more technically difficult mathematics (facilitating richer, more realistic models), assumptions that are hard to understand or justify substantively (highlighting the political intuitions underlying a model's results), and a complicated set of methods for extracting implications from models. We present an accessible introduction to the central monotone comparative statics results and a series of practical tools for using these techniques in applied models (with reference to original sources, when relevant). Throughout we demonstrate the techniques with examples drawn from political science .  相似文献   
104.
This paper examines a number of demographic aspects in congressional districts and states that played important roles in a series of Congressional votes on environmental issues in 2000. These characteristics include urbanization or population density, education, income, race, and employment. Our findings are mixed. While we find some evidence (at least in Senate votes) that population density is a positive predictor of “pro-environment” votes, we also find that things commensurate with the Environmental Kuznets Curve such as income, education, and lifestyle also play an important role in environmental voting.  相似文献   
105.
106.
警务工作必须随着社会的发展变化而不断进行调整和改良。进入21世纪后,苏格兰社会发生了许多深刻的变化,与之相适应,苏格兰警察正面临着一系列挑战和问题。未来苏格兰警务工作改革包括八个热点问题,即社区警务、警察的领导与管理、打击犯罪工作、毒品问题、青少年问题、警察在整个刑事司法体系中的角色转变、警察责任与警察投诉以及中央警务与地方警务两种模式之间的选择。  相似文献   
107.
Public policy may be determined as much by what cannot be agreed to by politicians and organized interests as by what can. Focusing on the inability of organized groups to credibly promise that their members will fully report revenues to tax authorities, I develop an incomplete-contracts lobbying model that shows that the provision of collective goods may be influenced by the anticipated tax compliance of economic sectors as well as by the organization of interests. Data from a survey of firms in Eastern Europe and the former Soviet Union are broadly supportive of the theory: the ability of firms to hide revenues from tax authorities rivals conventional collective-action variables in explaining variation in collective-goods provision, but only in that part of the postcommunist world where differences in revenue hiding across sectors are especially large.  相似文献   
108.
Digby Anderson 《Society》2002,39(3):34-41
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109.
110.
The purpose of the pilot study was to examine the interrelationship between social support, risk-level, and safety actions for 2 groups of suicidal adolescents (50 attempters and 50 ideators), who had presented for an acute assessment at an outpatient mental health service. A social support model was proposed in which it was thought that information related to patients' social support would impact upon the types of risk-level and safety actions made by clinicians. Data was collected from a total of 100 patient files, utilizing the acute assessment reports (e.g., reports assessing risk of self-harm). Findings show that groups differed significantly on indices of negative support severity, positive support, and risk-level. Limited support was found for the proposed social support model. Limitations and implications for future research are discussed.  相似文献   
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