Estimation for a first-order bifurcating autoregressive process with heavy-tail innovations

Asymptotics of an alternative extreme-value estimator for the autocorrelation parameter in a first-order bifurcating autoregressive (BAR) process with non-gaussian innovations are derived. This contrasts with traditional estimators whose asymptotic behavior depends on the central part of the innovation distribution. Within any BAR model, the main concern is addressing the complex dependency between generations. The inability of traditional methods to handle this dependency motivated an alternative procedure. With the combination of an extreme-value approach and a clever blocking argument, the dependency issue within the BAR process was resolved, which in turn allowed us to derive the limiting distribution for the proposed estimator through the use of regular variation and non-stationary point processes. Finally, the implications of our extreme-value approach are discussed with an extensive simulation study that not only assesses the reliability of our proposed estimate but also presents the findings for a new estimator of an unknown location parameter θ and its implications.     

Permutation tests of scale using deviances

Robust tests for comparing scale parameters, based on deviances—absolute deviations from the median—are examined. Higgins (2004) proposed a permutation test for comparing two treatments based on the ratio of deviances, but the performance of this procedure has not been investigated. A simulation study examines the performance of Higgins’ test relative to other tests of scale utilizing deviances that have been shown in the literature to have good properties. An extension of Higgins’ procedure to three or more treatments is proposed, and a second simulation study compares its performance to other omnibus tests for comparing scale. While no procedure emerged as a preferred choice in every scenario, Higgins’ tests are found to perform well overall with respect to Type I error rate and power.     

Activities of the U.S. Department of Health and Human Services

In this essay, Don Winstead and Ann McCormick describe HHS's efforts to improve existing data systems and create new ones to advance our understanding of "the condition of the low-income population before and after welfare reform." They confirm the seriousness of the problems that the other authors raise about various national, state, and local data sets, such as attrition and the inability to capture "the new variation in programs across the country." Their main sources of data are the SPD; the SIPP; and state-based administrative data on programs such as TANF, food stamps, and Medicaid.     

Staying safe while consuming alcohol: a qualitative study of the protective strategies and informational needs of college freshmen

OBJECTIVE: In this qualitative study, the authors examined how students attempt to minimize harm to themselves and others when drinking. PARTICIPANTS: The authors recruited freshmen at a large, mid-Atlantic US public university during the fall semester of 2005 to participate in 8 focus groups. METHODS: The moderator's guide was developed through an iterative process that included input from experts and pilot testing. The researchers audiotaped focus group conversations, transcribed them, and subjected them to an interrater reliability check. Analysis was based on the framework of Information-Motivation-Behavioral Skills Model and a phenomenological approach. RESULTS: College students have a repertoire of coping strategies they use in an attempt to safeguard themselves and their friends from harm when drinking. Strategies encompass planning a safe context for drinking, using safety measures to minimize harm when drinking, and taking care of someone who has consumed too much alcohol. CONCLUSIONS: A harm-reduction focus that acknowledges and builds on existing protective strategies may be a promising avenue for alcohol interventions.     

Rural Appalachian High School Students’ College‐Going and STEMM Perceptions

The authors examined perceptions of key social cognitive career theory (Lent, Brown, & Hackett, 1994) variables related to college‐going and science, technology, engineering, math, and medical (STEMM) careers in 10th and 11th graders (N = 892) attending 3 rural Appalachian high schools. The authors examined differences in perceptions related to gender, prospective 1st‐generation college student status, and the presence or absence of aspirations to pursue a STEMM career. Young women and young men scored similarly on all but 1 dependent variable, college‐going self‐efficacy (young women scored higher). Students who had STEMM career aspirations had higher scores on every measure than those who did not. Results suggest examining a 3rd prospective 1st‐generation college student status group—students who are unsure of their parents’ education level—as a distinct group in future research. By examining the college‐going and STEMM attitudes of rural Appalachian high school students, this study advances the literature and informs practitioners on reducing educational and vocational inequalities in this region.     

A revised approach to racism in youth multiculture: the significance of schoolyard conversations about sex,dating and desire

Anxieties about social cohesion in multicultural societies have prompted scrutiny of how young people negotiate culturally diverse spaces. A key perspective of the literature at the intersections of youth studies and urban multiculture is that young people shift between racist and convivial modes of relationality to navigate their complex social worlds. Drawing on ethnographic fieldwork in a culturally diverse high school in Melbourne, Australia, I suggest that this binary framing fails to capture some of the diverse logics and practices within multicultural youth sociality. Reconciling dichotomous conceptual frames that position young people as moving back-and-forth between forms of exclusion and openness, I propose an alternative frame – a perverse form of everyday cosmopolitanism – through which to consider young people’s intercultural relations. To do this, I draw on young people’s conversations about sex, dating and desire as an entry point for new theorising about racism. Race and ethnicity were cornerstones of students’ frequent discussions about sexual ‘tastes’ and activity, discourses that have racist histories and effects. However, students did not understand their social world in such terms. These students’ social practices offer a situated illustration of how racism can function as part of a more inclusive cosmopolitan ethos in young lives, which I term ‘perverse cosmopolitanism’.     

Destroyed by Slavery? Slavery and African American Family Formation Following Emancipation

This study introduces a new sample that links people and families across 1860, 1880, and 1900 census data to explore the intergenerational impact of slavery on black families in the United States. Slaveholding—the number of slaves owned by a single farmer or planter—is used as a proxy for experiences during slavery. Slave family structures varied systematically with slaveholding sizes. Enslaved children on smaller holdings were more likely to be members of single-parent or divided families. On larger holdings, however, children tended to reside in nuclear families. In 1880, a child whose mother had been on a farm with five slaves was 49 % more likely to live in a single-parent household than a child whose mother had been on a farm with 15 slaves. By 1900, slaveholding no longer had an impact. However, children whose parents lived in single-parent households were themselves more likely to live in single-parent households and to have been born outside marriage.     

Delirium: a very common problem you may not recognize

Older adults with multiple pre-existing conditions are admitted to hospitals with acute illnesses and injuries every day. Delirium is not recognized by clinicians across health care settings. With awareness of risk factors and knowledge of delirium, nurses can play a pivotal role in the early identification, treatment, and, most important, prevention of delirium in older adults. Nurses often display a lack of knowledge related to delirium and the complex symptoms that appear differently in the presence of other complicating co-morbid conditions in aging adults. Nurses play a crucial role in keeping patients safe and ensuring optimal outcomes, regardless of the setting. With the growing population of older adults and the expected increases in chronic illness and dementia, delirium is a problem nurses are likely to experience in all practice settings. Knowing what to look for facilitates recognizing the risk and acting early to minimize (or even prevent) delirium.