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61.
Massonnet G Buzzini P Jochem G Stauber M Coyle T Roux C Thomas J Leijenhorst H Van Zanten Z Wiggins K Russell C Chabli S Rosengarten A 《Journal of forensic sciences》2005,50(5):1028-1038
A collaborative study on Raman spectroscopy was carried out by members of the ENFSI (European Network of Forensic Science Institutes) European Fibres Group (EFG) on three dyed fibers: two red acrylics and one red wool. Raman instruments from six different manufacturers were tested as well as nine different laser wavelengths ranging from blue (lambda = 458 nm) to near infrared-NIR (lambda = 1064 nm). This represents the largest comparison study of Raman analytical parameters carried out on identical fiber samples. For the chosen fiber and dye samples, red lasers (lambda = 633 and 685 nm) gave the poorest spectral quality whereas blue (458 nm), green (514 nm) and near infrared lasers (785, 830 and 1064 nm) provided average results. Blue (488 nm) and green lasers (532 nm) globally gave the best quality spectra. Fluorescence problems were often encountered with some of the excitation wavelengths and therefore a flexible Raman instrument equipped with different lasers can be recommended to measure forensic fiber samples. The instrument should also be equipped with a Raman microscope in order to be able to focus on a single fiber. This study shows that Raman spectroscopy usually enables the identification of the main dye present in a colored fiber; however, minor dye components are much more difficult to detect. SERRS (Surface Enhanced Resonance Raman Scattering) techniques give an improvement of the dye's spectral intensity but no spectral improvement was observed for the two red acrylic and red wool fibers tested. 相似文献
62.
Buzzini P Massonnet G Birrer S Egli NM Mazzella W Fortini A 《Forensic science international》2005,152(2-3):221-234
Experimental data useful for the interpretation of paint evidence recovered during burglary cases were obtained. A population study was carried out on 41 blue crowbars seized on suspects in Switzerland and 37 blue paints traces found at burglary scenes. Paint traces were also searched on the blades of 207 crowbars seized by the police in Switzerland and 24 white traces were analysed: these paints were analysed using infrared spectroscopy (FTIR) in order to estimate relative frequencies of each paint type. Simulated contacts were carried out between crowbars and painted wood in order to study the phenomenon of transfer and to evaluate the amount of paint transferred: a total of 198 simulations were carried out including individual, successive and cross transfer. The paint properties such as the chemical composition and its age influenced the amount of paint transferred. Cross transfer from the tool paint to the wood and vice versa was regularly observed. Moreover, secondary transfer of paint coming from the preceding wooden surfaces was also systematically observed: this could establish links between several burglary scenes and a suspected tool. A scenario of a burglary case involving the cross transfer between tool and household paints is proposed as a numerical example: the evaluation of such case was formalised using likelihood ratios based on the experimental data obtained. 相似文献
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A Linear Poisson Autoregressive Model: The Poisson AR(p) Model 总被引:1,自引:0,他引:1
Time series of event counts are common in political scienceand other social science applications. Presently, there arefew satisfactory methods for identifying the dynamics in suchdata and accounting for the dynamic processes in event countsregression. We address this issue by building on earlier workfor persistent event counts in the Poisson exponentially weightedmoving-average model (PEWMA) of Brandt et al. (American Journalof Political Science 44(4):823843, 2000). We developan alternative model for stationary mean reverting data, thePoisson autoregressive model of order p, or PAR(p) model. Issuesof identification and model selection are also considered. Wethen evaluate the properties of this model and present bothMonte Carlo evidence and applications to illustrate. 相似文献
67.
The position of departmental secretaries has been under debate. There are claims they have been politicised; they have been placed on term appointments. This article examines the careers of departmental secretaries for the last 50 years. It illustrates the changes in their length of tenure, age of departure, mobility and qualifications. The recent profile shows the need for debate about the position and the future of departmental secretaries. 相似文献
68.
Mixed electoral systems seek to combine elements from different voting methods so as to maximise the numbers of individually accountable constituency MPs, while achieving more proportional outcomes in terms of parties' representation. This paper looks in detail at two kinds of mixed systems: variants of the Additional Member System; and AV Plus (or SV Plus). We examine how they would have operated in British conditions during the 1990s—how ballot papers would be structured, how voters respond to them and what electoral outcomes would have resulted. Both approaches offer good prospects for achieving a consensus amongst electoral reformers on an alternative to first-past-the-post elections. We also show how the Jenkins Commission's proposals can be located within the broader development of 'British AMS' by the Labour and Liberal Democrat parties. In addition, we quantify the main impacts of the policy choices which the Commission made in designing the proposed system to be submitted to a referendum. The British case will be a key one for the wider debate in political science about the endogenisation of voting system changes within party systems. 相似文献
69.
Patrick C. McKenry Sharon Price-Bonham Shirley L. O'Bryant 《Journal of youth and adolescence》1981,10(5):327-337
Adolescence is perhaps the most difficult period of child rearing for parents. This study attempted to identify disciplinary techniques used by parents as perceived by mothers, fathers, and their adolescent children. Results indicated several significant areas of intrafamilial disagreement in regard to disciplinary techniques utilized, although all subjects tended to agree that some form of verbal reasoning was the primary disciplinary technique utilized with these adolescents.This study was funded, in part, by the Ohio Agricultural Research and Development Center (H-644) and the School of Home Economics, The University of Georgia.Received his Ph.D. in child and family studies from the University of Tennessee. Current interests include adolescent development, family influences on sex-role development, and dual-work families.Received her Ph.D. in sociology from Iowa State University. Major interests include family research methodology, assessment of family power, and marital dissolution.Received her Ph.D. in educational psychology from the University of Texas. Current research interests include parenting, sex roles, and socialization across the life-span. 相似文献
70.
This study was divided into two parts. The first part consisted of an investigation of the frequency of television viewing among a sample of 2302 15-year-olds in 12 comprehensive schools. Subjects were divided into two groups, high and low frequency viewers, according to their own estimate of viewing time. The general picture which emerged (with some overlap of scores) was that high frequency viewers tended to be more neurotic and introverted; less intelligent; had less favorable attitudes to school; were less likely to think sport was important; were more likely to be bored in their leisure time; and possessed different social attitudes than low frequency viewers. The second part of the study investigated the program preferences of a subsample of over 900 subjects drawn from the main study. Little difference was found in the program preferences of high and low frequency viewers, but clear differences of preference were found between the sexes.Received his Ph.D. from the University of Aberdeen. Main research interests include social factors influencing education, adolescence, sports psychology, community education, and social psychology.Received her M.Ed. from the University of Aberdeen. Main research interests include community education and television. 相似文献