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941.
Methadone is a potent analgesic and sedative. It is widely used in the treatment of heroin addiction and is often encountered in forensic specimens. In electron impact (EI) gas chromatography/mass spectrometry (GC/MS) mode, methadone produces predominantly a m/z 72 ion, which is not sufficiently characteristic for identification. Determination of the molecular ion, which can be achieved using chemical ionization (CI) provides diagnostic information and better identification of the drug. This paper describes the development of a positive ion CI GC/MS procedure, using a liquid reagent gas and ion trap instrumentation, for the determination of methadone and its metabolites in urine. CI generally produces a single molecular ion spectrum, but optimization of the reagent gas parameters increases the fragmentation of the molecule, allowing determination of ion ratios if required. The procedure is sensitive, diagnostic and is currently in routine use in our laboratory. 相似文献
942.
Human mitochondrial DNA (mtDNA) analysis is a valuable forensic tool, useful in cases where the amount of extracted DNA is low or highly degraded. Population databases are used to determine the relative rarity of a particular profile obtained in a forensic case. Rather than full DNA sequence information, sequence profiles are compared to a reference sequence, and the differences from the reference are recorded in forensic databases. A standard method is proposed for characterizing length variants, and examples are described using actual human control region mtDNA profiles. Consistency in alignment and nomenclature avoids inadvertently describing two sequences as different when in fact they are the same. 相似文献
943.
D Williams M Lewis T Franzen V Lissett C Adams D Whittaker C Tysoe R Butler 《Science & justice》2004,44(2):89-94
Establishing the biological sex of human remains is a very important part of identifying victims of fire when severe soft tissue destruction has occurred. Deciduous (children's) teeth were exposed to a range of incineration temperatures 100-500 degrees C for 15 minutes. Polymerase Chain Reaction (PCR) amplification was used to identify specific human amelogenin regions. There was successful identification of human biological sex, from deciduous teeth exposed to incineration temperatures of 200 degrees C and below, using standard ethidium bromide gel staining. There was greater sensitivity using fragment analysis by laser induced fluorescence which achieved sex identification from some teeth heated to 400 degrees C. 相似文献
944.
Kevin MarshAuthor Vitae 《Orbis》2014,58(4):604-620
This article reviews power transition theory and emerging threats to U.S. national security. It then analyzes how the 2014 QDR will ensure U.S. relative power decline and how the strategy fails to effectively counter the rise of China and Russia as challenger states in the international system. Finally, several policy options are proposed to address the deficiencies of the QDR and to counter an increasingly aggressive China and revisionist Russia. 相似文献
945.
Angi M. Christensen Ph.D. Kevin J. Horn J.D. Victoria A. Smith M.A. 《Journal of forensic sciences》2014,59(4):1046-1048
When searching underwater crime scenes or disaster scenes for fragmentary human remains, it may be advantageous for forensic divers to be able to detect the presence of bones and teeth among other marine materials (such as shells and rocks). In terrestrial environments, this can typically be accomplished by visual and instrumental methods, but underwater conditions make it difficult to employ detection and sorting techniques in these environments. This study investigates fluorescence of bones and teeth and other marine materials using a submersible alternate light source (ALS) and concludes that an ALS can be a useful tool for detecting bones and teeth in underwater searches as well in terrestrial searches and laboratory environments. The results could impact the methods and equipment used by forensic divers and forensic anthropologists when searching for skeletal remains, potentially increasing the quantity and efficiency of forensic evidence recovered. 相似文献
946.
947.
J.C. Barnes Brian B. Boutwell Kevin M. Beaver Chris L. Gibson John P. Wright 《Journal of criminal justice》2014
Purpose
Many criminological scholars explore the social causes of crime while giving little consideration to the possibility that genetic factors underlie the observed associations. Indeed, the standard social science method (SSSM) assumes genetic influences do not confound the association between X and Y. Yet, a nascent stream of evidence has questioned the validity of this approach by revealing many criminological variables are at least partially affected by genetic influences. As a result, a substantial proportion of the literature may be misspecified due to uncontrolled genetic factors. No effort has been made to directly estimate the extent to which genetic confounding has biased the associations presented in criminological studies.Methods
The present study seeks to address this issue by drawing on simulated datasets.Results/Conclusions
Results suggest genetic confounding may account for a negligible portion of the relationship between X and Y when their correlation (ryx) is larger than the correlation between genetic factors and Y (i.e., ryx > ryg). Genetic confounding appears to be much more problematic when the correlation between X and Y is in the moderate-to-small range (e.g., ryx = .20) and the genetic effect is in the moderate-to-large range (e.g., ryg ≥ .30). 相似文献948.
Joshua D. Clinton David E. Lewis Jennifer L. Selin 《American journal of political science》2014,58(2):387-401
Does the president or Congress have more influence over policymaking by the bureaucracy? Despite a wealth of theoretical guidance, progress on this important question has proven elusive due to competing theoretical predictions and severe difficulties in measuring agency influence and oversight. We use a survey of federal executives to assess political influence, congressional oversight, and the policy preferences of agencies, committees, and the president on a comparable scale. Analyzing variation in political influence across and within agencies reveals that Congress is less influential relative to the White House when more committees are involved. While increasing the number of involved committees may maximize the electoral benefits for members, it may also undercut the ability of Congress as an institution to collectively respond to the actions of the presidency or the bureaucracy. 相似文献
949.
Gary E. Hollibaugh Jr. Gabriel Horton David E. Lewis 《American journal of political science》2014,58(4):1024-1042
To what extent do presidents select appointees based upon campaign experience and connections? The answer to this question has important implications for our understanding of presidential management and political leadership. This article presents a theory explaining where presidents place different types of appointees and why, focusing on differences in ideology, competence, and non‐policy patronage benefits among potential appointees. We develop a formal model and test its implications with new data on 1,307 persons appointed in the first six months of the Obama administration. The empirical results broadly support the theory, suggesting that President Obama was more likely to place appointees selected for non‐policy patronage reasons in agencies off his agenda, in agencies that shared his policy views, and where appointees are least able to affect agency performance. We conclude that patronage continues to play an important role in American politics, with important consequences for campaigns, presidential politics, and governance. 相似文献
950.