Multivariate analysis for estimating the age of a bloodstain

Our objective is to provide crime laboratories with a technique for estimating the age of a bloodstain. Toward that goal, we have used multiplexed, real-time RT-PCR (or qPCR) to determine the relative stability of different-sized segments of the same RNA species as well as differences in stability between two different RNAs' change over time in bloodstains. Our results indicate that a multivariate analysis of the changing ratio of the different RNA segments can be used to differentiate between samples of different ages in the defined population. Bloodstains from 29 of 30 donors could be partitioned into different ages using this technique. Although further improvements will be required before this approach can be implemented in crime laboratories, the multivariate analysis holds promise of providing a reliable approach for temporally linking a bloodstain to the commission of a crime or excluding a bloodstain as being irrelevant to the case in question.     

Simultaneous separation of different types of amphetamine and piperazine designer drugs by capillary electrophoresis with a chiral selector

The recent emergence of a new class of piperazine-type compounds has brought about the need for laboratory screening methods for both seized drugs and toxicological samples. These piperazine compounds, which include 1-benzylpiperazine (BZP) and 1-(3-trifluoromethylphenyl)piperazine (TFMPP), exhibit comparable physiological effects and can be substituted for the classic amphetamine-type drugs. We have optimized a chiral capillary electrophoresis (CE) separation that detects a set of 6 piperazine and 4 chiral amphetamine compounds in under 23 min using a 200 mM phosphate buffer at a pH = 2.8 with 20 mM hydroxypropyl- beta-cyclodextrin (HPbeta3CD). In addition to the above compounds, a series of "clandestine" BZP diHCl samples were also analyzed using this method to assess the ruggedness of the procedure. The novel CE separation was tailored to simultaneously detect these piperzine compounds in addition to amphetamine-type drugs. Distinct migration time and UV-spectral data were obtained for all compounds of interest.     

Political information processing: Question order and context effects

Data from two independent field experiments indicate that changes in question order and context may well account for an apparently precipitous decline of interest in politics at the time of the CPS 1978 American National Election Study. Evidence from a question order experiment with the SRC/CPS feeling thermometers also suggests that such contextual artifacts may not be atypical. Indeed, because of the many changes in the content and organization of the election studies over the years, context effects represent plausible rival hypotheses for a number of inexplicable shifts and trends in the time-series. In testing these hypotheses the authors derive and validate an information-processing model of how respondents infer their political states of mind from observations of their own question-answering behavior in the survey interview. In addition, the authors illustrate the wide applicability of the model tosubstantive problems in the discipline and its implications for the survey-based paradigm in political behavior research.     

Bail system development study

This systems analysis of the judicial and bail processes of two, large, Ohio jurisdictions provides an empirical data base for the courts to utilize in designing, implementing, and evaluating new or modified bail and court procedures.     

An unusual autoerotic death: asphyxia with an abdominal ligature

A case of accidental death resulting from an autoerotic episode involving a high abdominal ligature is reported. Pathologic findings, physical evidence, and the psychological investigation are discussed.     

Measuring the Distribution of Crime and Its Concentration

Objectives

Generally speaking, crime is, fortunately, a rare event. As far as modelling is concerned, this sparsity of data means that traditional measures to quantify concentration are not appropriate when applied to crime suffered by a population. Our objective is to develop a new technique to measure the concentration of crime which takes into account its low frequency of occurrence and its high degree of concentration in such a way that this measure is comparable over time and over different populations.

Methods

This article derives an estimate of the distribution of crime suffered by a population based on a mixture model and then evaluates a new and standardised measurement of the concentration of the rates of suffering a crime based on that distribution.

Results

The new measure is successfully applied to the incidence of robbery of a person in Mexico and is able to correctly quantify the concentration crime in such a way that is comparable between different regions and can be tracked over different time periods.

Conclusions

The risk of suffering a crime is not uniformly distributed across a population. There are certain groups which are statistically immune to suffering crime but there are also groups which suffer chronic victimisation. This measure improves our understanding of how patterns of crime can be quantified allowing us to determine if a prevention policy results in a crime reduction rather than target displacement. The method may have applications beyond crime science.