There have been many attempts to explain violent behavior, identify its causes, and predict its occurrence among youth and adults. Research and theoretical constructions have dealt with such far-ranging aspects as childhood health, peer and parental interactions, neuropsychological function, school and community support, and substance use and dependency. Theories have tended to focus on one or a few of these aspects, but there is an effort by many researchers to converge on an integrated approach. By demonstrating unique risk patterns in random samples of later-homicidal abused infants, children, and youth, violent and homicidal delinquents, and homicidal adults, five studies by Zagar and colleagues provide the best current empirical evidence for a view of the development of delinquency as a process of accumulating risks. These risks begin with prenatal substance exposure and continue with abusive or neglectful parenting, academic failure, court contacts, compromised executive function and resultant poor social functioning. Analysis by sex shows that males' and females' risks are virtually identical. Various theories are evaluated with respect to these empirical risk patterns for development of violence and homicide. A proposal for the necessary elements of a successful, overarching explanatory theory is offered.
NMR microscopic imaging is shown to be an excellent probe of the freezing and thawing phenomena of liquids in heterogeneous chemical systems, and, in addition, is capable of monitoring the freezing-thawing of mixed solvent systems. In the model mixed solvent system Me,SO-water, the chemical shift specific slice selective (C4S) imaging technique is used to obtain the spatial distributions of the concentrations and mobilities of the two individual solvents in test samples. Measurements of relaxation parameters make it possible to choose values of imaging parameters TE and TR to ensure quantitative reliability of the images. images of test samples generated at various temperatures demonstrate the qualitative relationship between image intensity and the Me,SO-water phase diagram. This series of experiments verifies that NMR microscopic imaging will be a powerful tool for the study of liquids within solid matrices, and in particular of cryoprotectant solvents in biological systems.
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