The effect of ionizing gamma radiation on natural and synthetic fibers and its implications for the forensic examination of fiber evidence

Circumstances of criminal activities involving radioactive materials may mean fiber evidence recovered from a crime scene could have been exposed to materials emitting ionizing radiation. The consequences of radiation exposed fibers on the result of the forensic analysis and interpretation is explored. The effect of exposure to 1-1000 kGy radiation doses in natural and synthetic fibers was noticeable using comparative forensic examination methods, such as optical microscopy, microspectrophotometry, and thin-layer chromatography. Fourier transform infrared spectroscopy analysis showed no signs of radiation-induced chemical changes in any of the fiber structures. The outcome of the comparative methods highlights the risk of "false negatives" associated in comparing colors of recovered fibers that may have been exposed to unknown radiation doses. Consideration of such results supports the requirement to know the context, including the environmental conditions, as much as possible before undertaking a forensic fiber examination.     

Students' perceptions of parents' and teachers' qualities of interpersonal relations

A sample of 561 predominantly white, midwestem high school students, grades 10–12, rated both a parent and a teacher on the Barrett-Lennard Relationship Inventory. Students were assigned randomly to rate a teacher in either a required subject or an elective subject and either their mother or their father. Sex cleavage was found in 12th-grade students who rated samegender teachers higher on warmth than they rated opposite-gender teachers. Evidence for developmental differences came from 11th and 12th graders who reported greater warmth from their parents than did 10th graders. Twelfth graders also perceived greater empathy from parents than did 10th graders. Eleventh-and 12th-grade students also perceived greater warmth from parents than from teachers. Overall, girls perceived greater genuineness from parents and teachers than did boys. Finally, students who lived with the parent they rated perceived greater warmth and congruence from that parent than did students who lived apart from their parent.This article was based on the first author's dissertation.Received Ph.D. from Kansas State University.Received Ph.D. in educational psychology from the University of Nebraska-Lincoln. Major research interests are writing processes and academic studyingReceived Ph.D. in Counselor Education from University of Wyoming.