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81.
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Krista Brady M.S. Becky Stilley B.S. Maria Olds B.S. Terry O'Neill B.S. James Egan Ph.D. Evan Durnal M.S. 《Journal of forensic sciences》2017,62(4):1015-1021
Commercial‐off‐the‐shelf (COTS) materials were evaluated as surface samplers for the Department of Homeland Security Chemical Forensics Program. The program helps evidence collectors identify trace chemical residues at incident scenes. COTS items are widely available, produced in large lots, and with strict controls. Chemical attribution signatures were collected from common surfaces. Eight tape lift candidates were considered, five were chosen based on performance and tested for analytical interferences and extraction efficiencies with 14 chemicals. Three products (duct tape, print lifters, command strips) were evaluated for uptake from common interior surfaces (glass, tile, ABS plastic). Duct tape provided highest recoveries across all surfaces. Even the most volatile analytes were detected in the ABS plastic samples (nondetections in others), regardless of tape lift material used. The porous plastic substrate provides better target retention than glass and tile surfaces. Forensic field operators should sample surfaces made of ABS plastic (keyboards, remotes, phones, etc.) whenever possible. 相似文献
83.
Cory P. Haberman Evan T. Sorg Jerry H. Ratcliffe 《Journal of Quantitative Criminology》2017,33(3):547-567
Objectives
The present study examined if Weisburd’s (Criminology 53(2):133–157, 2015) law of crime concentration held across different theoretically relevant temporal scales.Methods
The cumulative percentages of Philadelphia, PA USA street blocks and intersections experiencing 25 and 50 % of street robberies by hour of the day, days of the week, and seasons of the year were compared to the bandwidth percentages established by Weisburd (2015). Different analyses were used to determine the stability of the micro-places’ street robbery levels within the three temporal scales.Results
We found that the cumulative percentages of street blocks and intersections experiencing 25 and 50 % of street robberies at each of the three temporal scales closely matched the bandwidth percentages expected from Weisburd (2015) and some micro-places experienced street robberies across all temporal periods while others had more isolated temporal concentrations.Conclusion
Weisburd’s (2015) law of crime concentration holds across different theoretically relevant temporal scales, and future criminology of place studies should not ignore temporal crime patterns. Further, it may be possible to refine hot spots policing approaches by incorporating spatial–temporal crime concentrations.84.
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Kerr T Oleson M Wood E 《Canadian HIV/AIDS policy & law review / Canadian HIV/AIDS Legal Network》2004,9(2):13-19
Due to the ongoing health crisis among injection drug users in Vancouver, Canada, there have been repeated calls for the establishment of safe injection sites (SISs) since the early 1990s. In April 2003, in response to a large-scale police crackdown and government inaction, a group of activists opened an unsanctioned SIS in Vancouver's Downtown Eastside (DTES). The 327 Carrall Street SIS operated for 181 days despite considerable police harassment and limited financial support. During the operation of the SIS, volunteers supervised over 3000 injections and demonstrated the feasibility of a user-run low-threshold SIS. The experience of the SIS provides valuable lessons for those seeking to advance the interests of injection drug users through community mobilization and direct action approaches. In this article, Thomas Kerr, Megan Oleson, and Evan Wood describe the events surrounding the establishment, operation, and closing of the unsanctioned SIS, and outline the lessons learned. 相似文献
89.
Post-blast residues are potential interferents to chemical detection of landmines. To assess the potential problem related to 2,4,6-trinitrotoluene (TNT), its post-blast residue was identified and quantified. In the first part of this study laboratory-scale samples of TNT (2 g) were detonated in a small-scale explosivity device (SSED) to evaluate the explosive power and collect post-blast residue for chemical analysis. Initiator size was large relative to the TNT charge; thus, issues arose regarding choice of initiator, residue from the initiator, and afterburning of TNT. The second part of this study detonated 75 to 150 g of military-grade TNT (typical of antipersonnel mines) in 55-gal barrels containing various witness materials (metal plates, sand, barrel walls, the atmosphere). The witness materials were analyzed for explosive residue. In a third set of tests, 75-g samples of TNT were detonated over soil (from Fort Leonard Wood or Sandia National Laboratory) in an indoor firing chamber (100 by 4.6 by 2.7 m high). Targeted in these studies were TNT and four explosive-related compounds (ERC): 2,4-dinitrotoluene (DNT), 1,3-dinitrobenzene (DNB), 2- and 4-aminodinitrotoluene (2-ADNT and 4-ADNT). The latter two are microbial degradation products of TNT. Post-blast residue was allowed to age in the soils as a function of moisture contents (5 and 10%) in order to quantify the rate of degradation of the principal residues (TNT, DNT, and DNB) and formation of the TNT microbial degradation products (2-ADNT and 4-ADNT). The major distinction between landmine leakage and post-blast residue was not the identity of the species but relative ratios of amounts. In landmine leakage the DNT/TNT ratio was usually greater than 1. In post-blast residue it was on the order of 1 to 1/100th of a percent, and the total amount of pre-blast residue (landmine leakage) was a factor of 1/100 to 1/1000 less than post-blast. In addition, landmine leakage resulted in low DNT/ADNT ratios, usually less than 1, whereas pre-blast residues started with ratios above 20. Because with time DNT decreased and ADNT increased, over a month the ratio decreased by a factor of 2. The rate of TNT degradation in soil observed in this study was much slower than that reported when initial concentrations of TNT were lower. Degradation rates yielded half-lives of 40 and 100 days for 2,4-DNT and TNT, respectively. 相似文献
90.
Evan M. Berman 《The Journal of Technology Transfer》1990,15(3):5-12
This research examines the impact of research and development (R&D) consortia on the competitiveness of American companies.
It also concludes that since passage of the 1984 National Collaborative Research Act, which allows companies to jointly perform
research, only a few R&D consortia have been formed and they do not have much impact on companies through applications of
new technology. It is suggested that R&D consortia may have more impact on firms that are catching-up technologically or for
which the particular research is tangential to their core business.
He holds a Ph.D. in public policy from the George Washington University (1988), and has worked for the National Science Foundation,
the Congressional Office of Technology Assessment, and the National Academy of Sciences. His interests focus on technology,
economic competitiveness, and government policy. He has recently published on these topics in Research Policy (August 1990),
and Policy Studies Review (Spring 1991, forthcoming). 相似文献