The Effectiveness of Trace DNA Profiling—A Comparison Between a U.S. and a U.K. Law Enforcement Jurisdiction

Recovery, profiling, and speculative searching of trace DNA (not attributable to a body fluid/cell type) over a twelve‐month period in a U.S. Crime Laboratory and U.K. police force are compared. Results show greater numbers of U.S. firearm‐related items submitted for analysis compared with the U.K., where greatest numbers were submitted from burglary or vehicle offenses. U.S. multiple recovery techniques (double swabbing) occurred mainly during laboratory examination, whereas the majority of U.K. multiple recovery techniques occurred at the scene. No statistical difference was observed for useful profiles from single or multiple recovery. Database loading of interpretable profiles was most successful for U.K. items related to burglary or vehicle offenses. Database associations (matches) represented 7.0% of all U.S. items and 13.1% of all U.K. items. The U.K. strategy for burglary and vehicle examination demonstrated that careful selection of both items and sampling techniques is crucial to obtaining the observed results.     

Origin,Analytical Characterization,and Use of Human Odor in Forensics

Developing a strategy to characterize the odor prints of individuals should be relevant to support identification obtained using dogs in courts of justice. This article proposes an overview of the techniques used for the forensic profiling of human odor. After reviewing the origin of human odor—both genetic and physiological—the different analytical steps from sample collection to statistical data processing are presented. The first challenge is the collection of odor, whether by direct sampling with polymer patches, cotton gauze, etc., or indirect sampling with devices like Scent Transfer Unit. Then, analytical techniques are presented. Analyses are commonly performed with gas chromatography coupled with mass spectrometry. As they yield large amounts of data, advanced statistical tools are needed to provide efficient and reliable data processing, which is essential to give more probative value to information.     

Use of pepper spray in policing: retrospective study of situational characteristics and implications for violent situations

Pepper spray (OC) is a policing tool aimed to prevent or stop aggressive behavior by quickly and temporarily incapacitate without injuring. To date, few studies have investigated OC’s operational usefulness and limitations. OC reduced violent behavior in 93% of the 936 incidents investigated. However, the operative range was often <2 m and it took between 3 and 5 s of spraying before obtaining effect, partly owing to the difficulties of hitting a small, sometimes erratically moving target. Collateral hits were noted in 24% of the incidents, whereof 90% were other officers. Noteworthy, in 21% of incidents officers put themselves at large personal risk by using OC at close range against people armed with lethal weapons. Hence, OC emerges as a suitable tool for handling low threat situations but lacks key traits to ensure safe and efficient policing of high threat situations, e.g., handling armed assailants.     

行政行为对民事审判的拘束效力研究

在民事诉讼中,民事争议与行政争议交叉处理问题实质上是行政行为对民事审判的拘束效力问题。通过分析其成因及借鉴域外之经验,可以找到解决这一问题的思路：首先要判断该行政行为是否构成＂先决问题＂,即行政行为是否具有先决性,是否是尚未发生形式确定力的非无效行政行为。在构成＂先决问题＂的前提下,以行政行为对私法关系的作用效果为依据确定民事审判权的审查限度,即对确认性行政行为、形成性行政行为、裁决性行政行为分别适用民事先行、先行后民、行政附带的司法审查机制。     

Shoe print examinations: effects of expectation, complexity and experience

Even though trace evidence is becoming more and more important in legal cases, only little is known about the influence of task and context factors on comparative judgments. In the present study we investigated how expectations and complexity affect shoe print examinations and to what extent differences exist between beginners and experienced examiners. Twelve examiners assessed similarity between a shoe print and a shoe for eight different cases. For half the cases expectation was induced by providing additional incriminating evidence. A complex case meant that the print was relatively noisy, for example because the perpetrator rotated his foot. A simple case meant that the print was clear. The results showed that there was no effect of expectation and no effect of experience. Only complexity affected the examiners' assessments: when the background was noisy, the acquired features received a lower evidential value than when the background was clear. Apparently, examiners compensated for the quality of the print and were more cautious in drawing conclusions when prints were less clear. Even though the results allow for some optimism with regard to the influence of expectations on shoe print examinations, it has to be taken into account that the Dutch procedure is supported by a formal guideline, which may (partly) explain the present findings.     

The Role of Peer Contacts in the Relationship Between Parental Knowledge and Adolescents' Externalizing Behaviors: A Latent Growth Curve Modeling Approach

The purpose of the present study was to examine the direct and indirect effects (through peer contacts) of parental knowledge on adolescents’ delinquent and aggressive problem behavior, using latent growth curve modeling. A sample of 457 13- to 14-year old adolescents at first measurement wave (M=13.27; SD=0.45 years) filled out questionnaires about their parents, peers, and problem behavior three times with 1-year intervals in between. Regarding initial levels of behavior, both direct and indirect effects of parental knowledge were found on aggressive as well as on delinquent behavior. When the rate of change in behaviors was considered, only direct effects were found for both types of problem behavior, whereas indirect effects were absent. Gender differences were also found, with stronger effects of parenting on both aggressive and delinquent problem behavior for boys and stronger effects of peer contacts on aggressive behavior for girls. The present study shows that different behaviors of the externalizing spectrum have different trajectories and diverse relations with parenting and should not be treated as identical.

Correction to Tzidony and Ravreby (1992): A Statistical Approach to Drug Sampling: A Case Study

Abstract:  In 1992, Tzidony and Ravreby presented a confidence interval for the total weight of a seizure of illicit drugs present in a population. Their approach has subsequently been applied by several researchers in the field. The formula on which their approach is based does, however, not fully take into account the proportion of drug units found in the sample. In this paper, a modification is presented that consistently uses the correct sample size in all terms of the confidence interval, based on the proportion of drug units found in the sample. The effective sample size is smaller than the original sample size, and this should consequently be accounted for in the estimation of the standard error and in the corresponding t -distribution. The new confidence interval is again based on the assumption that the proportion of drug units in the population is known after sampling.     

Recovery of Environmental Human DNA by Insects*,†

Abstract: We tested the hypotheses that foraging insects can acquire human DNA from the environment and that insect‐delivered human DNA is of sufficient quantity and quality to permit standard forensic analyses. Houseflies, German cockroaches, and camel crickets were exposed to dusty surfaces and then assayed for human mitochondrial and nuclear loci by conventional and qPCR, and multiplex STR amplification. Over two experiments, 100% of insect groups and 94% of dust controls tested positive for human DNA. Of 177 individuals, 33–67% tested positive and 13 yielded quantifiable human DNA (mean = 0.022 ± 0.006 ng; mean dust control = 2.448 ± 0.960 ng); four had at least one positive allele call for one or more locus; eight others showed multiple peaks at some loci. Results imply that application to routine forensic casework is limited given current detection methodology yet demonstrate the potential use of insects as environmental samplers for human DNA.     

Assessment of Silicone Polymer Composites for Environmental Forensic Applications: A Proof of Concept Study*

Abstract: This study evaluates the use of polydimethylsiloxane polymer composites (PDMS, Fe–PDMS) as a passive sampling media to preconcentrate analytes found in environmental settings. Samplers were made using commercially available silicone products. The composite samplers were assessed for their sorption properties using Atrazine and Irgarol 1051 as model compounds. The initial study assessed the utility of PDMS sheets as adsorption material by following analyte depletion from spiked water samples by solid‐phase microextraction gas chromatography/mass spectrometry (GC/MS). Follow‐up studies conducted at high and low concentrations using lab manufactured iron‐ PDMS rods (Fe–PDMS) showed effective uptake at differential rates from concentrations ranging between 1 μg/L and 10 μg/L. Adsorption mechanism was reversible, and compounds were recovered from the exposed materials and analyzed by liquid–liquid extraction‐GC/MS. Both composites showed better affinity for Irgarol 1051, 100% removal, than for Atrazine, 30% removal, likely representing their K_OW differences, 3.6 and 2.6, respectively. This “proof of concept” study demonstrates the positive implications for the use of silicon polymer composites as a monitoring tool for environmental forensic purposes.     

Dimensions of Chinese foreign conflict and cooperation: A research note

Key mediation attributes, such as mediating actors, the strategy they choose, and previous mediation experiences, are widely thought to influence the nature of a conflict management outcome. But how and when these features shape outcomes is not a straightforward matter, and a standard analysis of these factors does not lead to their widely anticipated results. Why? We develop a new analytical framework that argues that a dispute's intensity alters the conflict management processes. Furthermore, in order to observe this variation, we also need to expand the traditional, dichotomous notion of conflict management outcomes (success or failure) to include a fuller range of observed results. Using the most recent International Conflict Management data set and our new analytical framework, we analyze the effect on conflict management outcome of mediator (a) identity, (b) strategy and (c) history. We find that directive strategies and international mediators are effective in resolving high intensity conflicts, procedural strategies and regional mediators are effective in resolving low intensity conflicts, and that mediation history always affects resolution. Our results have implications for both the study and practice of international dispute mediation.