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101.
The analysis of motor oils has wide applications in the forensic science field from comparing lubricants transferred between an automobile and a victim or crime scene to differentiating the compositions of plastic explosives. In this study, 40 unused motor oils were analyzed and compared by high-temperature gas chromatography-mass spectrometry to determine the potential for oil individualization. Oil samples were also collected from the crankcase dipsticks of 30 cars. Twenty-six of these oils could be differentiated from each other based on visual comparisons of the unresolved envelope (baseline rise due to incomplete separation) and the resolved hydrocarbons in the raw total ion chromatograms (TICs) and smoothed TIC data. Four of these oils were analyzed as unknowns and were correctly related to the corresponding vehicle. The use of extracted ion profiles (EIPs) was explored as a means to further discriminate between the indistinct samples based on the polycyclic aromatic hydrocarbon (PAH) content. The research discussed in this paper demonstrated that differentiation of motor oils was possible by examining the TIC, smoothed TIC, and EIP data. 相似文献
102.
Peter A. Weiss Katherine J. Bell William U. Weiss 《Journal of Police and Criminal Psychology》2010,25(1):49-55
The purpose of the present study was to assess the effects of criminal malingering on the MMPI-2 Restructured Clinical (RC)
scales. Sixty undergraduate students were given the MMPI-2 twice. One administration was conducted according to the MMPI-2
manual, and the other was given with a special set of malingering instructions specific to a prison setting. The two MMPI-2
profiles for each participant were scored for both the Basic and RC scales. Eight participants were eliminated from the data
analysis due to validity (VRIN or TRIN) concerns. Data from the remaining 52 participants were analyzed using a 2 × 2 repeated
measures ANOVA. Results showed that, as expected, the participants achieved higher MMPI-2 scores in the malingering condition.
Also, participants achieved higher scores overall on the Basic scales and a significant interaction showed that participants
achieved higher scores on the Basic Scales in the malingering condition than on the RC scales in that condition. These results
supported prior research, indicating that malingerers produce elevated RC profiles. However, the present results also suggest
that the Basic scales may be more effective in actually detecting malingerers, mainly due to the much lower ceiling on the
RC scaled scores. Further implications of these findings for research and clinical work are also discussed. 相似文献
103.
104.
The ability to obtain DNA profiles from trace biological evidence is routinely demonstrated with so-called ‘touch DNA evidence’, which is generally perceived to be the result of DNA obtained from shed skin cells transferred from a donor's hands to an object or person during direct physical contact. Current methods for the recovery of trace DNA employ swabs or adhesive tape to sample an area of interest. While of practical utility, such ‘blind-swabbing’ approaches will necessarily co-sample cellular material from the different individuals whose cells are present on the item, even though the individuals' cells are principally located in topographically dispersed, but distinct, locations on the item. Thus the act of swabbing itself artifactually creates some of the DNA mixtures encountered in touch DNA samples. In some instances involving transient contact between an assailant and victim, the victim's DNA may be found in such significant excess as to preclude the detection and typing of the perpetrator's DNA. In order to circumvent the challenges with standard recovery and analysis methods for touch DNA evidence, we reported previously the development of a ‘smart analysis’ single cell recovery and DNA analysis method that results in enhanced genetic analysis of touch DNA evidence. Here we use the smart single cell analysis method to recover probative single source profiles from individual and agglomerated cells from various touched objects and clothing items belonging to known donors. We then use the same approach for the detection of single source male donor DNA in simulated physical contact/assault mixture samples (i.e. male ‘assailant’ grabbing the wrist, neck or clothing from the female ‘victim’, or being in transient contact with bedding from the ‘victim’). DNA profiles attributable to the male or female known donors were obtained from 31% and 35% of the single and agglomerated bio-particles (putative cells) tested. The known male donor ‘assailant’ DNA profile was identified in the cell sampling from every mixture type tested. The results of this work demonstrate the efficacy of an alternative strategy to recover single source perpetrator DNA profiles in physical contact/assault cases involving trace perpetrator/victim cellular admixtures. 相似文献
105.
Toby Vickar Katherine Bache Barbara Daniel Nunzianda Frascione 《Science & justice》2018,58(4):282-286
Collecting sufficient template DNA from a crime scene sample is often challenging, especially with low quantity samples such as touch DNA (tDNA). Traditional DNA collection methods such as double swabbing have limitations, in particular when used on certain substrates which can be found at crime scenes, thus a better collection method is advantageous. Here, the effectiveness of the M-Vac® Wet-Vacuum System is evaluated as a method for DNA recovery on tiles and bricks. It was found that the M-Vac® recovered 75% more DNA than double swabbing on bricks. However, double swabbing collected significantly more DNA than the M-Vac® on tiles. Additionally, it was found that cell-free DNA is lost in the filtration step of M-Vac® collection. In terms of peak height and number of true alleles detected, no significant difference was found between the DNA profiles obtained through M-Vac® collection versus double swabbing of tDNA depositions from 12 volunteers on bricks. The results demonstrate that the M-Vac® has potential for DNA collection from porous surfaces such as bricks, but that alterations to the filter apparatus would be beneficial to increase the amount of genetic material collected for subsequent DNA profiling. These results are anticipated to be a starting point to validate the M-Vac® as a DNA collection device, providing an alternative method when DNA is present on a difficult substrate, or if traditional DNA collection methods have failed. 相似文献
106.
107.
This paper addresses a critical but almost unexamined aspect of the Low Income Housing Tax Credit (LIHTC) program – whether its use (and in particular, the siting of developments in high-poverty/high-minority neighborhoods), is associated with increased racial segregation in the metropolitan area. Using data from the Department of Housing and Urban Development (HUD) and the Census, supplemented with data on the racial composition of LIHTC tenants in three states, we examine three potential channels through which the LIHTC could affect segregation: where LIHTC units are built relative to where other low income households live, who lives in these tax credit developments, and changes in neighborhood racial composition in neighborhoods that receive tax credit projects. The evidence on each of these channels suggests that LIHTC projects do not contribute to increased segregation, even those in high poverty neighborhoods. We find that increases in the use of tax credits are associated with declines in racial segregation at the metropolitan level. 相似文献
108.
Forensic arthropod succession patterns are known to vary between regions. However, the northern habitats of the globe have been largely left unstudied. Three pig carcasses were studied outdoors in Whitehorse, Yukon Territory. Adult and immature insects were collected for identification and comparison. The dominant Diptera and Coleoptera species at all carcasses were Protophormia terraneovae (R‐D) (Fam: Calliphoridae) and Thanatophilus lapponicus (Herbst) (Fam: Silphidae), respectively. Rate of decomposition, patterns of Diptera and Coleoptera succession, and species dominance were shown to differ from previous studies in temperate regions, particularly as P. terraenovae showed complete dominance among blowfly species. Rate of decomposition through the first four stages was generally slow, and the last stage of decomposition was not observed at any carcass due to time constraints. It is concluded that biogeoclimatic range has a significant effect on insect presence and rate of decomposition, making it an important factor to consider when calculating a postmortem interval. 相似文献
109.
Matthew R. Lockett Ph.D. Katherine A. Mirica Ph.D. Charles R. Mace Ph.D. Robert D. Blackledge M.S. George M. Whitesides Ph.D. 《Journal of forensic sciences》2013,58(1):40-45
This paper describes a method for determining the density of contact trace objects with magnetic levitation (MagLev). MagLev measurements accurately determine the density (±0.0002 g/cm3) of a diamagnetic object and are compatible with objects that are nonuniform in shape and size. The MagLev device (composed of two permanent magnets with like poles facing) and the method described provide a means of accurately determining the density of trace objects. This method is inexpensive, rapid, and verifiable and provides numerical values—independent of the specific apparatus or analyst—that correspond to the absolute density of the sample that may be entered into a searchable database. We discuss the feasibility of MagLev as a possible means of characterizing forensic‐related evidence and demonstrate the ability of MagLev to (i) determine the density of samples of glitter and gunpowder, (ii) separate glitter particles of different densities, and (iii) determine the density of a glitter sample that was removed from a complex sample matrix. 相似文献
110.
In ‘Power to the People: Evidence from a Randomised Field Experiment on Community-Based Monitoring in Uganda’ (2009), Björkman and Svensson show that a relatively simple intervention – providing community-level health service delivery information and guidance on community-based monitoring – improved provider behaviour, health care utilisation, and health outcomes. In this paper we conduct a pure replication of the original study and extend the original analysis. Overall, we find that the intervention modified healthcare provider behaviours and utilisation, but that the results surrounding the programme’s impact on health outcomes appear less robust. 相似文献