Evaluation of contact and non-contact trapping efficiencies of human scent chemical profiles and their stabilities under different environmental conditions

Establishing an association between the scent a perpetrator left at a crime scene to the odor of the suspect of that crime is the basis for the use of human scent identification evidence in a court of law. Law enforcement agencies gather evidence through the collection of scent from the objects that a perpetrator may have handled during the execution of the criminal act. The collected scent evidence is consequently presented to the canines for identification line-up procedures with the apprehended suspects. Presently, canine scent identification is admitted as expert witness testimony, however, the accurate behavior of the dogs and the scent collection methods used are often challenged by the court system. The primary focus of this research project entailed an evaluation of contact and non-contact scent collection techniques with an emphasis on the optimization of collection materials of different fiber chemistries to evaluate the chemical odor profiles obtained using varying environment conditions to provide a better scientific understanding of human scent as a discriminative tool in the identification of suspects. The collection of hand odor from female and male subjects through both contact and non-contact sampling approaches yielded new insights into the types of VOCs collected when different materials are utilized, which had never been instrumentally performed. Furthermore, the collected scent mass was shown to be obtained in the highest amounts for both gender hand odor samples on cotton sorbent materials. Compared to non-contact sampling, the contact sampling methods yielded a higher number of volatiles, an enhancement of up to 3 times, as well as a higher scent mass than non-contact methods by more than an order of magnitude. The evaluation of the STU-100 as a non-contact methodology highlighted strong instrumental drawbacks that need to be targeted for enhanced scientific validation of current field practices. These results demonstrated that an individual's human scent components vary considerably depending on the method used to collect scent from the same body region. This study demonstrated the importance of collection medium selection as well as the collection method employed in providing a reproducible human scent sample that can be used to differentiate individuals.

Risk and resilience factors associated with delinquent behavior among African -American adolescent males

Juvenile crime is a social problem of increasing concern to many citizens in the United States. In 2000, there were an estimated 2.4 million juvenile arrests for a variety of crimes ranging from misdemeanors to violent felony offenses. African American males are disproportionately represented among juvenile offenders in the United States. In 2000, black youth were approximately 16% of the U.S. population between the ages of 10–17; however, they accounted for 42% of juvenile arrests for violent crime. ^ This study explored putative factors associated with juvenile offending among a sample of African American adolescent males. The independent variables in this study were academic achievement, religiosity, parenting styles and discrimination. The dependent variables were delinquent behavior and arrest. The data used in this study were from a larger NIDA funded longitudinal study that included approximately 425 African American youths. The data collection method involved structured interviews and questionnaires. The participants for the original study were selected via random sampling from all students attending middle school in Miami-Dade County. The study examined the hypotheses that African American males retrospectively reporting (a) high academic achievement, (b) high religiosity, (c) authoritarian parenting and (d) low perceptions of discrimination are less likely to be involved in delinquent behavior and are also less likely to be arrested. ^ Results indicated that among African American adolescent males, delinquent behavior had a significant relationship (p < .05) with academic achievement, perceived discrimination and the interaction between perceived discrimination and experienced discrimination. Arrest was significantly related to academic achievement (p < .001), religious perception (p < .05), and church attendance (p < 05). Neither dependent variable was significantly related to parenting styles. ^ The findings indicated that experimental studies are needed to clarify cause and effect relationship among the variables associated with juvenile offending among African American males, which may differ from those associated with juvenile offending among other groups. ^

Risk and resilience factors associated with delinquent behavior among African American adolescent males

Juvenile crime is a social problem of increasing concern to many citizens in the United States. In 2000, there were an estimated 2.4 million juvenile arrests for a variety of crimes ranging from misdemeanors to violent felony offenses. African American males are disproportionately represented among juvenile offenders in the United States. In 2000, black youth were approximately 16% of the U.S. population between the ages of 10-17; however, they accounted for 42% of juvenile arrests for violent crime. This study explored putative factors associated with juvenile offending among a sample of African American adolescent males. The independent variables in this study were academic achievement, religiosity, parenting styles and discrimination. The dependent variables were delinquent behavior and arrest. The data used in this study were from a larger NIDA funded longitudinal study that included approximately 425 African American youths. The data collection method involved structured interviews and questionnaires. The participants for the original study were selected via random sampling from all students attending middle school in Miami-Dade County. The study examined the hypotheses that African American males retrospectively reporting (a) high academic achievement, (b) high religiosity, (c) authoritarian parenting and (d) low perceptions of discrimination are less likely to be involved in delinquent behavior and are also less likely to be arrested. Results indicated that among African American adolescent males, delinquent behavior had a significant relationship (p The findings indicated that experimental studies are needed to clarify cause and effect relationship among the variables associated with juvenile offending among African American males, which may differ from those associated with juvenile offending among other groups.

An Examination of Qualitative Empirical Studies at the AHRD from 1999-2003: Method, Rationale for Method, Data Collection, Sampling Strategies, and Integrity Measures

The paper examines the nature of qualitative empirical studies published in the AHRD proceedings from 1999-2003 and discusses findings on method, rationale for method, data collection, sampling strategies, and integrity measures.