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Forensic entomology requires the fast and accurate identification of insects collected from a corpse for estimation of the postmortem interval (PMI). Identification of specimens is traditionally performed using morphological features of the insect. Morphological identification may be complicated however by the numerical diversity of species and physical similarity between different species, particularly in immature stages. In this study, sequencing was performed to study the mitochondrial DNA (mtDNA) as the prospective basis of a diagnostic technique. The sequencing focused on a section of the cytochrome oxidase I encoding region of mtDNA. Three species of calliphorid (blow flies) commonly associated with corpses in western Australia, Calliphora dubia, Chrysomya rufifacies and Lucilia sericata, in addition to specimens of Calliphora augur and Chrysomya megacephala were studied. Phylogenetic analysis of data revealed grouping of species according to genus. The DNA region sequenced allowed identification of all species, providing high support for separation on congeneric species. Low levels of variation between some species of the same genus however indicate that further sequencing is required to locate a region for development of a molecular-based technique for identification. 相似文献
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Bloodhounds are used to trail fleeing felons and missing persons. In order to start a trail, the dog must be presented with a person's scent. There are many hypotheses on what a bloodhound smells while trailing. The present study attempts to identify whether human scent is genetic, and if it is influenced by one's environment. Bloodhounds trained in human scent discrimination were used to differentiate between monozygotic twins, related and nonrelated persons, living together and apart. The first test required the dogs to run blind trails after being presented with the scent of one person in the pair, while the opposite person was hidden. The second test allowed the dogs to trail one person in the pair after both people were hidden. Results appear to demonstrate that bloodhounds rely heavily on genetic cues when differentiating between people. Environmental cues do not appear to significantly aid the bloodhound in scent discrimination. 相似文献
817.
Treatment of morphine, at room temperature, with a mixture of trifluoroacetic anhydride (TFAA) and acetic acid (20-30min) affords good yields of heroin. GC-MS and HPLC examination shows that heroin produced by this route to be extremely clean, but the product contains slightly less heroin than observed via the more traditional acetic anhydride (AA) route (76.1% versus 83.55%); and greater quantities of 3-MAM and 6-MAM (6.9% versus 0.75% and 7.13% versus 0.63%). The concentration ratios of the major alkaloid impurities were found to be both production method (TFAA and AA) as well as morphine extraction methodology dependant. Data contained herein describe the impact of this new production method on current intelligence efforts, largely by-passing existing heroin signature programs and the UNDCP's efforts to restrict access to key synthetic precursors. Given the methodology dependency we find that examination of the major alkaloid ratios is unsuitable for the development of a new heroin signature program. Further examination of the TFAA methodology allowed the identification of TFAA specific marker compounds, namely bis-trifluoroacetylmorphine (30), 3-trifluoroacetyl-6-acetylmorphine (31), 3-acetyl-6-trifluoroacetylmorphine (32) and trifluoroacetylcodeine (33). However, the hydrolytic lability of trifluroacetyl esters requires careful treatment of suspect samples, thus we propose a modification to existing HSP's in instances were the 6-MAM/WM ratio falls within the average minimum and maximum values of 6.17 and 17.32. 相似文献
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Harvey ML 《Journal of forensic sciences》2005,50(3):627-629
An important area of recent research in forensic entomology has been the use of insect DNA to provide identification of insects for fast and accurate estimation of time since death. This requires DNA to be extracted efficiently and in a state suitable for use in molecular procedures, and then stored on a long-term basis. In this study, Whatman FTA cards were tested for use with the Calliphoridae (Diptera). In particular, testing examined their ability to effectively extract DNA from specimens, and store and provide DNA template in a suitable condition for amplification using the polymerase chain reaction (PCR). The cards provided DNA that was able to be amplified from a variety of life stages, and thus appears to be of sufficient quality and quantity for use in subsequent procedures. FTA cards therefore appear suitable for use with calliphorids, and provide a new method of extraction that is simple and efficient and allows for storage and transportation without refrigeration, consequently simplifying the handling of DNA in forensic entomological cases. 相似文献
820.
Self-Control,Violent Offending,and Homicide Victimization: Assessing the General Theory of Crime 总被引:2,自引:0,他引:2
Alex?R.?PiqueroEmail author John?MacDonald Adam?Dobrin Leah?E.?Daigle Francis?T.?Cullen 《Journal of Quantitative Criminology》2005,21(1):55-71
Criminologists have long recognized that offending and victimization share common ground. Using Gottfredson and Hirschis general theory of crime, with its emphasis on self-control as a theoretical backdrop, we examine the extent to which self-control is related to both violent offending and homicide victimization. To examine this issue, we use 5-year post-parole data on violent offending and homicide victimization from a sample of parolees from the California Youth Authority. Using rare-events logistic regression models, results indicate that self-control is related to each outcome, but that other risk factors are also uniquely related to each outcome. The implications of this study for theory and future research are addressed.To whom correspondence should be addressed: Department of Criminology, Law and Society, University of Florida, P.O. Box 115950, 201 Walker Hall, Gainesville, FL 32611-5950; Phone: +1-352-392-1025, ext. 213; E-mail: apiquero@ufl.edu 相似文献