The optimal jury size when jury deliberation follows a random walk

The existing literature does not agree on the optimal jury size. We demonstrate that the probability of type I and type II errors is not sensitive to the number of jurors under the following three conditions: jurors receive independent signals about a defendant’s guilt during the evidence stage of the trial; the jurors truthfully reveal their signals before deliberations begin through their votes on the first ballot; and the jury’s deliberation follows a random walk. Since the opportunity cost of jury service is positive, this implies an optimal jury size of one.     

Removing interfering contaminations from gelatin lifters

Gelatin lifter is widely used for recovering shoeprints from crime scenes. Dusty shoeprints removed from paper with loose fibers, cloth or plasterboard, might be concealed by the detached fibers. A novel technique to clean the gelatin lifter from the interfering contaminations, using adhesive lifters, was developed. The adhesive lifter is applied directly on the surface of the gelatin lifter, and is removed instantly. The adhesive lifter removes the upper layer of the attached material on the gelatin lifter. After removing the concealing material from the hidden imprint, the quality of the visualized imprint is improved. The cleaning process can be applied as many times as needed and the optimum number is different for each substrate. The small dust particles comprising the shoeprint remained attached to the sticky side of the gelatin lifter even though the adhesion force applied by the adhesive lifter is great. Repeating the procedure too many times could harm the quality of the print severely, yet the advantages of this method are greater than the risks of relocation of image quality reduction.     

Genipin--a novel fingerprint reagent with colorimetric and fluorogenic activity

Genipin, the hydrolytic product of geniposide, which is extracted from gardenia fruit, shows good potential as a fingerprint reagent. It develops latent fingerprints on paper as blue impressions with good contrast and resolution. Even very faint impressions that are barely visible in ambient light will fluoresce brightly upon illumination at ca. 590 nm and are best viewed with a barrier filter above 630 nm. Potential advantages of genipin are the combination of colorimetric and fluorogenic activity in one reagent as well as its being a safe and environmentally friendly natural product.     

Classification Improvements in Automated Gunshot Residue (GSR) Scans

Classification of particles as gunshot residues (GSRs) is conducted using a semiautomatic approach in which the system first classifies particles based on an automatic elemental analysis, and then, examiners manually analyze particles having compositions which are characteristic of or consistent with GSRs. Analyzing all the particles in the second stage is time consuming with many particles classified by the initial automated system as being potentially GSRs excluded as such by the forensic examiner. In this paper, a new algorithm is developed to improve the initial classification step. The algorithm is based on a binary tree that was trained on almost 16,000 particles from 43 stubs used to sample hands of suspects. The classification algorithm was tested on 5,900 particles from 23 independent stubs and performed very well in terms of false positive and false negative rates. A routine use of the new algorithm can reduce significantly the analysis time of GSRs.     

A comparative research of two lifting methods: electrostatic lifter and gelatin lifter

Two-dimensional dust shoeprints are often of very high resolution and contain unique features. Lifting these prints in the most effective method may contribute much to preserving these fine details. A research was conducted by experts from Israel and Switzerland to compare gelatin lifters and electrostatic lifters for lifting shoeprints. Several substrates were chosen, and on each material a set of dry dust shoeprints was made. A set of wet prints was made on paper as well. The shoeprints were approximately of the same quality, and the only variable was the nature of the material. On substrates indifferent to the method used, the preferable sequence was tested. Gelatin lifter was superior on most substrates and for wet prints. The superior sequence for using both methods is electrostatic lifting followed by gelatin lifter.     

The diminishing role of governments in cable policy

Abstract The article examines the role of governments in the transition in cable policy in the three largest media countries of Europe (Britain, France and Germany). In theoretical terms it is argued that the involvement of governments in determining the course of development of cable systems has comprised three main stages. In the first stage, governments tried to ignore cable and prevent the establishment of cable infrastructure. In the second stage, governments regulated the technology in order to promote a national cable policy and encourage the overall development of the broadcasting media. In the third stage, although at different speeds and perceptions, governments deregulated cable by giving permission to market forces to dominate cable's development and abandoning the social goals of cable policy.     

A Mixture Model for the Number of Gunshot Residues Found on Suspects' Hands

Quantifying the strength of gunshot residue (GSR) evidence requires scientific knowledge about the number of particles expected to be found on individuals who were or were not involved in a shooting. However, controlled experiments demand expensive resources in terms of microscope time and labor, which restricts the data of most studies to only a small group of individuals. We suggest a novel method that exploits data collected routinely on suspects during the daily work of forensic laboratories. These observational data relate to both persons who were involved in a shooting and innocent individuals. We suggest a mixture approach with different models for the number of gunshot residue particles in each group and develop an iterative algorithm to estimate the probabilities of observing the evidence under the defense proposition that the suspect is innocent and under the prosecution assumption that he is not. The method is applied to data of more than 500 suspects collected by the Israel National Police Division of Identification and Forensic Science. The analysis shows that the probability of finding three or more GSR particles on the hands of innocent suspects is very small, less than 1.5 in 1000 cases. Our new method enables researchers to use data on real cases, possibly supplemented by experimental data, in order to estimate the probabilities of a given GSR finding under the defense and prosecution propositions.     

Unusual contact marks: connecting the hubcap to the wheel of the car

A case of homicide and attempted homicide is described. The comparison of tire-marks linked the suspect's vehicle to the scene of crime only with low certainty. However, the comparison of the pressure mark on the hubcap found at the scene, with the balance weight on one of the wheels of the suspect's car, connected the suspect to the scene of crime with high certainty.