The use of Hemastix® severely reduces DNA recovery using the BioRobot® EZ1

Abstract: The choice of reagents for presumptive tests for blood, and subsequent extraction methodologies, can significantly affect both the quantity and quality of purified DNA. Blood samples directly tested with Hemastix^® yielded <1% of the DNA recovered from untested samples when purified using the Qiagen BioRobot^® EZ1 and EZ1^® DNA Investigator kit. Full short tandem repeat profiles were obtained from both tested and untested samples, suggesting that the Hemastix^® reagent(s) affect DNA binding, rather than produce DNA damage. The Hemastix^® inhibition of DNA yield could be overcome by the addition of MTL buffer to the sample prior to extraction. Laboratories may wish to modify current procedures for extracting blood samples, utilize other extraction/purification methodologies, or inform their submitting agencies to avoid direct exposure of questioned bloodstains to Hemastix^® reagents.     

Family and Individual Predictors of Late Adolescents' Romantic Relationships

The present study examined parent–adolescent conflict and late adolescents' attachment anxiety and depressive symptoms as predictors of late adolescents' romantic relationships. Questionnaires assessing parent–adolescent conflict resolution behaviors, adolescent–romantic partner conflict resolution behaviors, and adolescent attachment anxiety and depressive symptoms were completed by 256 college students (198 females and 58 males). Using hierarchical regression analyses, statistical models were tested wherein adolescent–romantic partner conflict resolution behaviors were regressed on mother–adolescent and father–adolescent conflict resolution behaviors and adolescents' attachment anxiety and depressive symptoms. All four predictor variables explained significant portions of the variance in adolescent–romantic partner conflict resolution behaviors; however, different predictors were found for females and males. For females, mother–adolescent and father–adolescent conflict resolution strategies and adolescent attachment anxiety were significant predictors. In contrast, father–adolescent conflict resolution behaviors and adolescent depressive symptoms were significant predictors for males. Findings highlight the differential role of familial and individual attributes in female and male adolescents' romantic relationship functioning.     

A model for disaggregating political change

We present a model for identifying the components of aggregate change in an electorate between two points in time. When the electorate is constant in size, change in the mean opinion disaggregates into two components: conversion among those who continue to participate in the electorate (Stayers), and replacement of those who drop out of the electorate at Time₁ (Dropouts) by Newcomers to the electorate at Time₂. We add to this simple formulation the possibility of variation in the size of the electorate. When an electorate expands, the model includes a mobilization term to accommodate the fact that there are more Newcomers at Time₂ than Dropouts at Time₁. When an electorate shrinks in size, the demobilization term reflects the fact that Newcomers as a group are smaller than Dropouts. The model includes appropriate weights for each component so that the change in opinion (or any other aggregate characteristic in the electorate) can be allocated across the three components. We apply the model to Iowa caucus attenders in both parties between 1984 and 1988, and we suggest that the model can be also productively applied to a variety of contexts besides nomination politics, where fluctuations in the size of electorates are significant.Ronald B. Rapoport. College of William and Mary.