Informativeness of NGS Analysis for Vaginal Fluid Identification

The identification of vaginal fluids in forensic examinations plays an important role in crime scene reconstruction. Molecular detection of vaginal bacterial communities can lead to the correct discrimination of body fluids. These kinds of studies can be performed through multiplex real‐time PCR using primers for a specific selection of bacteria. The availability of next‐generation sequencing (NGS) protocols provided for the extension of the analysis to evaluate the prokaryotes present in specimens. In this study, DNA was extracted from 18 samples (vaginal, oral, fecal, yoghurt) and analyzed by real‐time PCR and NGS. The comparison between the two approaches has demonstrated that the information developed through NGS can augment the more conventional real‐time PCR detection of a few key bacterial species to provide a more probative result and the correct identification of vaginal fluid from samples that are more forensically challenged.     

Determination of vehicle speed from recorded video using the open-source software Kinovea

Video devices of different kind often record traffic accidents, including vehicle-pedestrian collisions and hit-and-run accidents. In these cases, the vehicle speed is valuable information because it can assist the investigators in an accident reconstruction. This paper examines the use of Kinovea, an open-source video annotation tool designed for sport analysis, to estimate vehicle speed in forensic videos. Kinovea does not require a complex methodology, and it can be used to make the calculation easily. A series of vehicle driving experiments using an appropriately calibrated speed radar system (so called Scout Speed) were carried out, and measurements were compared with the estimated speed. In controlled conditions, the comparison of Scout reference speed and calculated average vehicle speed by means of Kinovea found an average difference of 0.43 km/h, with a margin of error of ±0.64 km/h. In addition, further preliminary tests were carried out to check the reliability of the measurements under lower resolution conditions. Also, in these cases the calculations were in line with the ground truth. Therefore, in the tested conditions, Kinovea demonstrated to be an easy and reliable tool available for forensic video examiners. Further tests need to be conducted in order to address the applicability of the measurement technique with true CCTV/surveillance video recordings.     

Identification of gunshot residue: a critical review

A review of the scientific papers published on inorganic gunshot residue (GSR) analysis permits to study how the particle analysis has shown its capability in detection and identification of gunshot residue. The scanning electron microscope can be the most powerful tool for forensic scientists to determine the proximity to a discharging firearm and/or the contact with a surface exposed to GSR. Particle analysis can identify individual gunshot residue particles through both morphological and elemental characteristics. When particles are detected on the collected sample, the analytical results can be interpreted following rules of a formal general interpretative system, to determine whether they come from the explosion of a primer or from other possible sources. The particles on the sample are compared with an abstract idea of "unique" GSR particle produced by the sole source of the explosion of a primer. "Uniqueness" is not the only problem related to GSR detection and identification for a forensic scientist. With "not-unique" particles interpretation of results is extremely important. The evidential strength of "not-unique" particles can increase with a more fruitful interpretative framework based on Bayes rule. For the assessment of the value of a GSR in linking a suspect and a crime, it is important to compare two hypothesis: the first can be that of the evidence if the suspect has been shooting in a specific situation, the second that of the evidence if the suspect was not involved in this shooting. This case specific or case-by-case approach is closer to what the court is interested in. The authors consider that a "case-by-case" approach should be followed whenever possible. Research of models and data such as those developed in other trace evidence material (fibres, glass, etc.) using a Bayesian approach is suggested in the interpretation of GSR.     

A forensic image processing environment for investigation of surveillance video

We present an image processing software suite, based on the Matlab environment, specifically designed to be used as a forensic tool by law enforcement laboratories in the analysis of crime scene videos and images. Our aim is to overcome some drawbacks which normally appear when using standard image processing tools for this application, i.e. mainly the lack of full control and documentation on the operations which have been performed on the images, and the absence of new, more sophisticated algorithms which can provide improved performances and "make the difference" in critical cases.     

Unusual sources of Sn in GSR. An experimental study by SEM and IBA

Gunshot Residue (GSR) produced by the discharge of a firearm often provides very useful information in criminal investigations in cases involving the use of firearms. Scanning Electron Microscopy equipped with an Energy Dispersive X-ray Spectrometer (SEM-EDS) is typically used worldwide to visualize micrometric particles constituting GSR and to analyse their elemental composition. The 2017 ASTM Standard guide for gunshot residue analysis by scanning electron microscopy/energy dispersive X-ray spectroscopy specifies that “Particles classified as characteristic of GSR will have one of the following elemental compositions: Lead, antimony, barium; Lead, barium, calcium, silicon, tin”. For the first time, the presence of an additional element, such as Sn, plays a key role in ASTM particle classification. It is known that some ammunitions, used for pistols, revolvers and rifles, contain tin foil discs for sealing the primer mixture into the cup, resulting in GSR particles containing Sn. The authors faced some cases in which Sn was unexpectedly found in GSR particles from a 0.22 Long Rifle derringer and from some 12 gauge shotguns. No tin foil discs are used in rimfire ammunitions and there is no published evidence of tin foil discs in shotshell ammunitions. Following a “case by case” approach, experimental research has been carried out to explain how Sn can be present in GSR particles when the last discharged cartridge also does not contain any Sn either in components and in the explosive charges.Moreover, the use of Particle Induced X-ray Emission (PIXE) showed the capability to overcome overlap ambiguity of Sb and Sn peaks in the X-ray spectra, being a possible key issue in real shooting cases if Sn quantities are below the lower limit of SEM detection, especially when Sb is also present.     

The Popular Front for the Liberation of Palestine during the First Intifada: From Opportunity to Marginalization (1987–1990)

Abstract

In understanding the decline of the Popular Front for the Liberation of Palestine (PFLP), the analysis of its political agency allows the identification of a pattern of policy fluctuation that recurs throughout several critical phases of its trajectory. In this regard, the First Intifada is a case in point. The new geographical setting, the strong network of affiliated organizations and the more favourable balance of power with Fatah represented a major opportunity for the PFLP to revive its political initiative and increase its political weight. However, the PFLP was unable to grasp this opportunity due to its inconsistencies in confronting the main challenges posed by the Intifada, namely Fatah’s diplomatic agenda, the relations with the PFLP’s branch in the Territories, the fragmentation of the Palestinian Left and the rise of the Islamist movement. Resorting to a systematic study of the PFLP’s official publications and to interviews with former and current militants, this article identifies the pattern of policy fluctuation that transformed the First Intifada into a turning point in its weakening process. This pattern acquires further relevance since it illustrates the basic poles of tensions behind the fluctuation of the PFLP’s political conduct throughout the following decades.     

An Alan Keyes Effect? Examining Anti-Black Sentiment Among White Evangelicals

Given its historical and contemporary importance, it is noteworthy that the relevant literature generally overlooks the role that religion and its accompanying values play in determining support for black candidates. In addressing this question, we review the historical and theological bases of evangelical attitudes toward blacks. We then present experimental results that examine evangelical attitudes toward blacks. We follow this with results from the 2006 Pennsylvania gubernatorial and U.S. Senate races to bolster the experimental findings. Finally, we discuss our findings and their implications for GOP attempts to recruit black candidates who can appeal to moderate white and black voters without losing support from the GOP’s evangelical base.