Random regression models for human immunodeficiency virus ribonucleic acid data subject to left censoring and informative drop-outs

Objectives in many longitudinal studies of individuals infected with the human immunodeficiency virus (HIV) include the estimation of population average trajectories of HIV ribonucleic acid (RNA) over time and tests for differences in trajectory across subgroups. Special features that are often inherent in the underlying data include a tendency for some HIV RNA levels to be below an assay detection limit, and for individuals with high initial levels or high ranges of change to drop out of the study early because of illness or death. We develop a likelihood for the observed data that incorporates both of these features. Informative drop-outs are handled by means of an approach previously published by Schluchter. Using data from the HIV Epidemiology Research Study, we implement a maximum likelihood procedure to estimate initial HIV RNA levels and slopes within a population, compare these parameters across subgroups of HIV-infected women and illustrate the importance of appropriate treatment of left censoring and informative drop-outs. We also assess model assumptions and consider the prediction of random intercepts and slopes in this setting. The results suggest that marked bias in estimates of fixed effects, variance components and standard errors in the analysis of HIV RNA data might be avoided by the use of methods like those illustrated.     

Managing Contradiction: Stockholder and Stakeholder Views of the Firm as Paradoxical Opportunity

Stockholder and stakeholder perspectives have been positioned in the literature as being in tension, and thus a potential source of innovation and change. However, researchers have overlooked a systematic examination of this presumption in theory and in practice. This study explores the ways that stockholder and stakeholder assumptions are presented by theorists and compares these with expressions of stockholder and stakeholder perspectives used by firms in practice. We argue that theoretical entrenchment dichotomizing these perspectives has disrupted the ability of researchers to leverage this tension. While scholarship remains trapped in a vicious cycle, we also argue that firms in practice express only the acceptance dimension of a virtuous cycle. Our empirical research demonstrates that firms accept and accommodate the paradoxical tension between managing for stockholders versus balancing the interests of stakeholders. This is evidenced by strategies we identify as book‐ending, cadence, continuous and simultaneous co‐mingling, and hybridization. We find that in practice these tensions are more integrated whereas in theory they are treated as more distinct and, often, in conflict. We suggest ways in which both scholarship and practice can better leverage tension as paradoxical opportunity.     

Institutionalizing Counter‐Memories of the U.S. Civil Rights Movement: The National Civil Rights Museum and an Application of the Interest‐Convergence Principle

During the post–Reconstruction era in the United States, white southerners marked the cultural landscape with monuments and memorials honoring the Confederate cause and its heroes. These racialized symbols enjoyed an undisputed claim to public squares and parks throughout the South. It was not until the late twentieth century that commemorations to the black freedom struggle were publicly supported. This analysis examines the institutionalization of counter‐memories of the civil rights movement in Memphis, Tennessee at the Lorraine Motel, the site of the assassination of Reverend Dr. Martin Luther King, Jr. The author draws on collective memory, cultural trauma, and social movements research as well as critical race theory to explain the creation of the National Civil Rights Museum. Using primary and secondary data sources the author examines how social memory agents, a changing political culture, and the passage of time mediated the cultural trauma of King's assassination and influenced the institutionalization of oppositional collective memories. Relying on Derrick Bell's interest‐convergence principle, the author concludes that the creation of this major memorial museum was a result of the convergence of white and black interests, specifically the economic and political interests of white elites and the cultural and political interests of black symbolic entrepreneurs.     

Reanalysis of the DEMS Nested Case‐Control Study of Lung Cancer and Diesel Exhaust: Suitability for Quantitative Risk Assessment

The International Agency for Research on Cancer (IARC) in 2012 upgraded its hazard characterization of diesel engine exhaust (DEE) to “carcinogenic to humans.” The Diesel Exhaust in Miners Study (DEMS) cohort and nested case‐control studies of lung cancer mortality in eight U.S. nonmetal mines were influential in IARC's determination. We conducted a reanalysis of the DEMS case‐control data to evaluate its suitability for quantitative risk assessment (QRA). Our reanalysis used conditional logistic regression and adjusted for cigarette smoking in a manner similar to the original DEMS analysis. However, we included additional estimates of DEE exposure and adjustment for radon exposure. In addition to applying three DEE exposure estimates developed by DEMS, we applied six alternative estimates. Without adjusting for radon, our results were similar to those in the original DEMS analysis: all but one of the nine DEE exposure estimates showed evidence of an association between DEE exposure and lung cancer mortality, with trend slopes differing only by about a factor of two. When exposure to radon was adjusted, the evidence for a DEE effect was greatly diminished, but was still present in some analyses that utilized the three original DEMS DEE exposure estimates. A DEE effect was not observed when the six alternative DEE exposure estimates were utilized and radon was adjusted. No consistent evidence of a DEE effect was found among miners who worked only underground. This article highlights some issues that should be addressed in any use of the DEMS data in developing a QRA for DEE.     

The Immigrant Paradox in Pregnancy: Explaining the First‐Generation Advantage for Latina Adolescents

The immigrant paradox is a population health pattern whereby later generation immigrant youth display less favorable outcomes when compared to first‐generation co‐ethnic peers. This study examines the role of number of sex partners in explaining the immigrant paradox in pregnancy among Latina adolescents. This secondary analysis utilized a nationally representative sample of Latinas in the National Longitudinal Study of Adolescent Health. As expected, first‐generation Latina adolescents demonstrated less risk than second‐ or third+ generation Latinas for becoming pregnant. Further, the lower number of sexual partners fully accounted for the first generation's advantage in lower rate of adolescent pregnancy. These findings have important implications for healthcare providers who work with Latina girls in pregnancy prevention.     

Variance estimation when donor imputation is used to fill in missing values

Donor imputation is frequently used in surveys. However, very few variance estimation methods that take into account donor imputation have been developed in the literature. This is particularly true for surveys with high sampling fractions using nearest donor imputation, often called nearest‐neighbour imputation. In this paper, the authors develop a variance estimator for donor imputation based on the assumption that the imputed estimator of a domain total is approximately unbiased under an imputation model; that is, a model for the variable requiring imputation. Their variance estimator is valid, irrespective of the magnitude of the sampling fractions and the complexity of the donor imputation method, provided that the imputation model mean and variance are accurately estimated. They evaluate its performance in a simulation study and show that nonparametric estimation of the model mean and variance via smoothing splines brings robustness with respect to imputation model misspecifications. They also apply their variance estimator to real survey data when nearest‐neighbour imputation has been used to fill in the missing values. The Canadian Journal of Statistics 37: 400–416; 2009 © 2009 Statistical Society of Canada     

Puerto rican drug users’ experiences of physical and sexual abuse: Comparisons based on sexual identities

This study integrates the results of quantitative and qualitative methods to elucidate the association between sexual identity and physical and sexual abuse among Puerto Rican drug users. A structured questionnaire was administered to 800 subjects in New York and 399 in Puerto Rico. A total of 93 subjects (7.9%) self‐identified as homosexual or bisexual. Gay males were significantly more likely than heterosexual males to report first occurrence of physical abuse by a family member in childhood. Both gay and bisexual males were more likely than their heterosexual counterparts to report first experiencing unwanted sex in childhood and intimate partner physical abuse later in life. Lesbians were more likely than female heterosexuals to report unwanted sex in childhood. Qualitative data were collected through in‐depth life histories with 21 subjects and suggest that gay and lesbian subjects perceive antihomosexual prejudice on the part of family members as one cause of childhood physical and sexual abuse.     

Linkages between Children's Beliefs about the Legitimacy of Aggression and Their Behavior

The purposes of this study were to learn whether children's beliefs about the legitimacy of aggression can be reliably assessed and whether these beliefs relate to children's everyday social behavior with peers, as well as their responses to hypothetical ambiguous provocation situations. Fourth- and fifth-grade students ( n = 781) responded to a 16-item questionnaire designed to measure children's beliefs about the legitimacy of aggression. Children's behavioral orientation was assessed using two methods: (1) children's responses to ten hypothetical situations involving ambiguous provocation, and (2) peer evaluations of children's aggressive, withdrawn, and prosocial behavior. Results indicated that children's beliefs about the legitimacy of aggression were reliably measured. Furthermore, results from both measures of behavioral style showed that children who believed strongly in the legitimacy of aggression were more aggressive, less withdrawn, and less prosocial. The findings suggest that one focus of efforts to decrease children's aggression should be the modification of their beliefs about the legitimacy of aggressive actions.