A Comparison of Thresholding Methods for Forensic Reconstruction Studies Using Fluorescent Powder Proxies for Trace Materials

Image segmentation is a fundamental precursor to quantitative image analysis. At present, no standardised methodology exists for segmenting images of fluorescent proxies for trace evidence. Experiments evaluated (i) whether manual segmentation is reproducible within and between examiners (with three participants repeatedly tracing three images) (ii) whether manually defining a threshold level offers accurate and reproducible results (with 20 examiners segmenting 10 images), and (iii) whether a global thresholding algorithm might perform with similar accuracy, while offering improved reproducibility and efficiency (16 algorithms tested). Statistically significant differences were seen between examiners’ traced outputs. Manually thresholding produced good accuracy on average (within ±1% of the expected values), but poor reproducibility (with multiple outliers). Three algorithms (Yen, MaxEntropy, and RenyiEntropy) offered similar accuracy, with improved reproducibility and efficiency. Together, these findings suggest that appropriate algorithms could perform thresholding tasks as part of a robust workflow for reconstruction studies employing fluorescent proxies for trace evidence.     

Lifting shoeprints using gelatin lifters and a hydraulic press

A method for lifting two-dimensional dust footwear marks on rough or porous surfaces, such as cardboard or cloth, using a hydraulic press, was examined. It was found that exerting pressure on the lifter by the press usually improves the quality of the results. When the shoeprints were on rough or soft surfaces, the prints transferred to the gelatin lifters were better than those obtained by the conventional method. In other cases, using the press did not improve the results but was much simpler to apply. Based on the results of this study, the hydraulic press/gelatin lifter method (the "press method") is used at the authors' laboratory, depending on the surface from which the shoeprint is to be lifted. It is the authors' intention to apply the method to other surfaces after finding the optimal pressure for surfaces with loose fibers.     

Educational Aspirations of Male and Female Adolescents from Single-Parent and Two Biological Parent Families: A Comparison of Influential Factors

Youth from single-parent families report lower educational aspirations than those from two-parent families. This study explored the influence of background factors (gender, grade, parental education and SES), parental involvement with education, academic self-concept, and peer influences on educational aspirations. The participants were Canadian adolescents; 2751 from two parent and 681 from single-parent families. ANOVA results showed that adolescents from single-parent families scored significantly lower than adolescents from intact families on educational aspirations, and other predictor variables. Hierarchical regression analysis showed that the pattern of relationships between educational aspirations and other factors was very similar for adolescents from both types of families; namely academic self-concept significantly predicted educational aspirations. The family involvement and background factors predicted educational aspirations via academic self-concept. Having academically oriented peers was especially beneficial to adolescents from single-parent families. Implications for intervention programs are discussed. The research was supported by a Social Sciences and Humanities Research Council of Canada Grant. Rashmi Garg is an Associate professor in the Department of Psychology at Laurentian University. She received her PhD in 1983 from the University of Ottawa. Basically she is interested in applied research in the areas of educational and psychological measurement and testing. More specifically she is interested in the adolescent's education and career development. Stella Melanson received a master's degree in Human Development from Laurentian University in 2003. She is working as a research data analysis coordinator for Ontario Early Years Education and Social Planning Council. Her interest is in early childhood education. Elizabeth Levin is an Associate Professor and Chair of the Department of Psychology at Laurentian University. She received her PhD in 1986 from the University of Waterloo. Her major research interests focus on parenting styles and children's conceptions of parenting.     

Reviews

Les relations de pouvoir façonnent le cours de l'existence du secteur pétrolier depuis la découverte et la commercialisation de l'or noir remontant au 19e siècle. Progressivement, quoique bien rapidement, cette substance devint le moteur de l'évolution économique mondiale toujours en vigueur. Étrangement, plusieurs études actuelles, que l'on rassemble sous la thèse de la malédiction des ressources (resource curse [RC]), semblent pourtant esquiver leur centralité à la compréhension de la paupérisation et des violences vécues chez les populations de certaines régions riches en ressources pétrolières. À travers la problématisation de la littérature analytique portant sur la RC appliquée à la situation chaotique de la région du delta du Niger au Nigéria et sa mise en relation avec les débats appréciatifs des pratiques de RSE (responsabilité sociale des entreprises), cet article démontre l'importance de prendre en compte l'ensemble des dimensions politiques du vécu de la RSE dans une réalité locale, nationale et internationale aux diverses ramifications "s'inter-constituant."