A Meta‐Analysis of Carbon Nanotube Pulmonary Toxicity Studies—How Physical Dimensions and Impurities Affect the Toxicity of Carbon Nanotubes

This article presents a regression‐tree‐based meta‐analysis of rodent pulmonary toxicity studies of uncoated, nonfunctionalized carbon nanotube (CNT) exposure. The resulting analysis provides quantitative estimates of the contribution of CNT attributes (impurities, physical dimensions, and aggregation) to pulmonary toxicity indicators in bronchoalveolar lavage fluid: neutrophil and macrophage count, and lactate dehydrogenase and total protein concentrations. The method employs classification and regression tree (CART) models, techniques that are relatively insensitive to data defects that impair other types of regression analysis: high dimensionality, nonlinearity, correlated variables, and significant quantities of missing values. Three types of analysis are presented: the RT, the random forest (RF), and a random‐forest‐based dose‐response model. The RT shows the best single model supported by all the data and typically contains a small number of variables. The RF shows how much variance reduction is associated with every variable in the data set. The dose‐response model is used to isolate the effects of CNT attributes from the CNT dose, showing the shift in the dose‐response caused by the attribute across the measured range of CNT doses. It was found that the CNT attributes that contribute the most to pulmonary toxicity were metallic impurities (cobalt significantly increased observed toxicity, while other impurities had mixed effects), CNT length (negatively correlated with most toxicity indicators), CNT diameter (significantly positively associated with toxicity), and aggregate size (negatively correlated with cell damage indicators and positively correlated with immune response indicators). Increasing CNT N₂‐BET‐specific surface area decreased toxicity indicators.     

A log-linear regression model for the odd Weibull distribution with censored data

We introduce the log-odd Weibull regression model based on the odd Weibull distribution (Cooray, 2006). We derive some mathematical properties of the log-transformed distribution. The new regression model represents a parametric family of models that includes as sub-models some widely known regression models that can be applied to censored survival data. We employ a frequentist analysis and a parametric bootstrap for the parameters of the proposed model. We derive the appropriate matrices for assessing local influence on the parameter estimates under different perturbation schemes and present some ways to assess global influence. Further, for different parameter settings, sample sizes and censoring percentages, some simulations are performed. In addition, the empirical distribution of some modified residuals are given and compared with the standard normal distribution. These studies suggest that the residual analysis usually performed in normal linear regression models can be extended to a modified deviance residual in the proposed regression model applied to censored data. We define martingale and deviance residuals to check the model assumptions. The extended regression model is very useful for the analysis of real data.     

Midpregnancy Marriage and Divorce: Why the Death of Shotgun Marriage Has Been Greatly Exaggerated

Conventional wisdom holds that births following the colloquially termed “shotgun marriage”—that is, births to parents who married between conception and the birth—are nearing obsolescence. To investigate trends in shotgun marriage, we matched North Carolina administrative data on nearly 800,000 first births among white and black mothers to marriage and divorce records. We found that among married births, midpregnancy-married births (our preferred term for shotgun-married births) have been relatively stable at about 10 % over the past quarter-century while increasing substantially for vulnerable population subgroups. In 2012, among black and white less-educated and younger women, midpregnancy-married births accounted for approximately 20 % to 25 % of married first births. The increasing representation of midpregnancy-married births among married births raises concerns about well-being among at-risk families because midpregnancy marriages may be quite fragile. Our analysis revealed, however, that midpregnancy marriages were more likely to dissolve only among more advantaged groups. Of those groups considered to be most at risk of divorce—namely, black women with lower levels of education and who were younger—midpregnancy marriages had the same or lower likelihood of divorce as preconception marriages. Our results suggest an overlooked resiliency in a type of marriage that has only increased in salience.     

Does Gender Equality Influence Volunteerism? A Cross-National Analysis of Women’s Volunteering Habits and Gender Equality

Research regarding the roles of women in society and in political and social organizations is large, with scholars focusing on the likelihood of political and social engagement. However, few of these studies examine the influence of gender on participation in voluntary organizations by utilizing cross-national data. This study intends to analyze the influence of gender on the type of organization that an individual volunteers and on whether these volunteering habits are influenced by the gender equality in a country. Is there segregation in the type of organizations men and women volunteer? Do women in more gender equal societies have similar volunteering patterns as men, or does the difference continue in volunteering? For this study, we use the World Values Survey from 1999 to 2002, to identify the differences in the types of organizations that men and women volunteer and discuss the impact gender equality has on these volunteering patterns.     

Affective ties and social information processing

We examined whether second‐ and fifth‐graders could display differentiated social information processing (SIP) about known peers varying in affective ties. Children's response evaluation and decision (RED) and goal importance ratings were obtained for nine ambiguous provocations involving their best friends, neutral peers, and enemies (three stories for each relationship). For each story, RED was assessed for hostile, competent and passive responses to provocation, and the importance of four social goals was rated. Both second‐ and fifth‐graders displayed RED that depended on both the type of relationship they had with the provocateur and on the type of response (hostile, competent or passive). Children's social goals were affected by their relationship with the provocateur. Younger children's failure to display sensitivity to situational cues in previous studies is likely due to the cognitive demands of reasoning about hypothetical characters rather than an insensitivity to situational cues, per se.     

Effectiveness and feasibility of a 10-minute employee stress intervention: Outdoor Booster Break

There is a growing recognition that workplace environments affect employee health. Nature contact exposures in the workplace have been shown to be healthful for employees. This pilot study was designed to test the feasibility and efficacy of a daily outdoor work break (Outdoor Booster Break) compared to a daily indoor break. A census of university office staff was invited to participate (N?=?244). Phase 1 focused on feasibility—participants (n?=?119) reported that the Outdoor Booster Break was feasible (74%), practical (80%), and worthwhile (83%). During Phase II we used a single-site randomized controlled trial (RCT) to examine the effects of an Outdoor Booster Break—compared with a control indoor work break group—for 4 weeks on employee stress. Perceived stress was measured at pretest and posttest for both conditions. Mean posttest stress scores were lower for both the control group (n?=?19) and the treatment group (n?=?18). A main effects ANCOVA model controlling for baseline stress revealed posttest stress was lower for the treatment group compared to controls (p?=?.041). Taking a work break appears to have stress-reducing benefits, but the Outdoor Booster Break reduced stress significantly more than an indoor break. Implications for employers, worksite health promoters, and future research are discussed.     

Varieties of Childhood Bullying: Values, Emotion Processes, and Social Competence

Understanding the nature of bullies and bullying is of considerable theoretical and practical importance. We offer a commentary on a recent debate on this topic between Sutton, Smith, and Swettenham (1999a, 1999b) and Crick and Dodge (1999). In this commentary, we first summarize the main points of the debate, including alternative views of bullies as social inadequates versus Machiavellian schemers. Then we clarify some unresolved issues concerning the nature and limits of social competence and the roles of values in both social competence and in bullying. Finally, it is argued that variations in children's emotion processes, such as emotionality and emotion regulation, also may underlie some of the individual differences that have been found in empathy, social information processing, and in reactive ('hot-headed') and proactive ('cold-blooded') aggressive and bullying patterns.     

Risk Communication Planning for the Aftermath of a Plague Bioattack

We create an influence diagram of how a plague bioattack could unfold and then use it to identify factors shaping infection risks in many possible scenarios. The influence diagram and associated explanations provide a compact reference that allows risk communicators to identify key messages for pre‐event preparation and testing. It can also be used to answer specific questions in whatever unique situations arise, considering both the conditions of the attack and the properties of the attacked populations. The influence diagram allows a quick, visual check of the factors that must be covered when evaluating audience information needs. The documentation provides content for explaining the resultant advice. We show how these tools can help in preparing for crises and responding to them.     

A continuous latent spatial model for crack initiation in bone cement

Summary.  Hip replacements rovide a means of achieving a higher quality of life for individuals who have, through aging or injury, accumulated damage to their natural joints. This is a very common operation, with over a million people a year benefiting from the procedure. The replacements themselves fail mainly as a result of the mechanical loosening of the components of the artificial joint due to damage accumulation. This damage accumulation consists of the initiation and growth of cracks in the bone cement which is used to fixate the replacement in the human body. The data come from laboratory experiments that are designed to assess the effectiveness of the bone cement in resisting damage. We examine the properties of the bone cement, with the aim being to estimate the effect that both observable and unobservable spatially varying factors have on causing crack initiation. To do this, an explicit model for the damage process is constructed taking into account the tension and compression at different locations in the specimens. A gamma random field is used to model any latent spatial factors that may be influential in crack initiation. Bayesian inference is carried out for the parameters of this field and related covariates by using Markov chain Monte Carlo techniques.