The forensic analysis of thermal transfer printing

Thermal transfer printing refers to printing processes that utilize heat to produce an image by either physical or chemical means or by a combination of both. As the technology has improved and the supplies have become less expensive, the use of thermal printing in the personal and business markets has increased significantly. Specifically, dye diffusion thermal transfer and thermal mass transfer have become predominant in the production of counterfeit credit cards, drivers' licenses, and other types of documents produced on plastic media. Chemical analysis by means of thin layer chromatography (TLC) has proven to be useful in characterizing various types of inks (e.g., writing and inkjet inks). In this study, the authors examined 81 different samples that included a total of 54 printer samples (43 photographic prints on paper and eleven plastic card samples) and 27 printer ribbons. A new TLC method was developed and tested utilizing a solvent system (80% n-hexane, 3% methyl ethyl ketone, and 17% ethyl acetate) that is capable of producing excellent resolution.     

Ego development in adolescence: Longitudinal studies

Adolescents from four schools (one inner-city, two suburban, and one private) were tested two or three times using the Washington University Sentence Completion Test of Ego Development. Testing intervals ranged from 1.5 to 6 years. About half (N=193) the original pool was retested at twelfth grade. Every sample showed a mean rise in ego level; for six of eight samples that rise was statistically significant. Every pair of testings showed a postive correlation between scores; 10 of 14 correlations were significantly different from zero. Thus both test-retest correlations (about 0.5) and change scores support the hypothesized sequence of ego development. Significant correlation between ego level and intelligence occurred in two schools (0.6 at elementary and junior high grades and 0.4 at twelfth grade), but correlation was about zero in the private school.These studies were supported by Grant MH-05115 and Research Scientist Award MH-00657, both from the National Institute of Mental Health, Public Health Service.Received her Ph.D. from Washington University. Main interest is adolescent development.Received her Ph.D. from the University of California, Berkeley. Main interest is theory and measurement of ego development.     

Object-oriented Bayesian networks for paternity cases with allelic dependencies

This study extends the current use of Bayesian networks by incorporating the effects of allelic dependencies in paternity calculations. The use of object-oriented networks greatly simplify the process of building and interpreting forensic identification models, allowing researchers to solve new, more complex problems. We explore two paternity examples: the most common scenario where DNA evidence is available from the alleged father, the mother and the child; a more complex case where DNA is not available from the alleged father, but is available from the alleged father’s brother. Object-oriented networks are built, using HUGIN, for each example which incorporate the effects of allelic dependence caused by evolutionary relatedness.