A new approach to statistical efficiency of weighted least squares fitting algorithms for reparameterization of nonlinear regression models

We study nonlinear least-squares problem that can be transformed to linear problem by change of variables. We derive a general formula for the statistically optimal weights and prove that the resulting linear regression gives an optimal estimate (which satisfies an analogue of the Rao-Cramer lower bound) in the limit of small noise.     

Dyadic Analyses of Preschool‐aged Children's Friendships: Convergence and Differences between Friendship Classifications from Peer Sociometric Data and Teacher's Reports

Peer sociometrics and teachers' friendship reports were compared in 2179 preschool dyads. One hundred twenty of 306 reciprocated friend dyads from peer sociometric data were also identified as good friends by their classroom teachers, and 301 of 600 of non‐reciprocated dyads in peer data were named as friends by one or both classroom teachers (overall kappa = .16). Friendship classifications from both peer and teacher data had significant relations with variables relevant to peer interactions, social skills, peer acceptance, and teacher‐rated scales (six of seven tests significant for peer data; five of eight significant for teacher data). Multilevel analyses indicated that friendship status effects were not qualified by classroom‐level differences. Findings suggest that sociometric tasks can identify preschoolers' peer friendships and that the range of correlates may be broader in peer‐choice data than in teachers' friendship evaluations.     

The Intergenerational Transmission of Social Capital: A Developmental Approach to Adolescent Social Capital Formation*

Previous scholarship has demonstrated the importance of individual characteristics and structural context for understanding social capital formation. However, a developmental approach to social capital formation has, so far, been absent. In this study, I argue that social capital formation must be understood intergenerationally as well as structurally. Using hierarchical linear modeling, I investigate the hypothesized intergenerational transmission of social capital using Waves 1 and 2 of the National Longitudinal Study of Adolescent Health. The results show that, in addition to individual characteristics, neighborhood‐level factors, and school‐level variables, parental social capital is an important predictor of adolescent social capital. This study also suggests that the intergenerational transmission of social capital functions, in part, through family structure and that structural differences account for only a relatively small share of the variation in adolescent social capital. Potential explanations for these findings are discussed.     

Relations Between Alphabetized Name Order and Nomination Counts in Peer Nomination Measures

Peer nominations, a central method for measuring peer relationships in developmental research, typically involve asking children or adolescents to choose peers who fit various criteria from an alphabetized roster of classmates or grade‐mates. Although such measures have been used for decades, very little research has investigated the effects of alphabetical name order on the number of nominations received by peers. This study collected peer nominations for 20 items among 607 eighth grade participants in two schools. Regression analyses showed that earlier name order significantly predicted higher nomination counts for eight of the items, and explained over 5 percent of the variance in four affective variables (friendship, acceptance, acquaintanceship, and received liking). Across variables, name order effects were negatively correlated with internal reliability of nominations, implying that order effects may be related to the consensus of the peer group. Name order also had a minimal effect on inter‐correlations among a subset of variables. Implications and concrete recommendations for controlling and reducing name order effects in future research are discussed.     

A divergence of opinion: how those involved in child and family social work are responding to the challenges of the Internet and social media

This discussion paper suggests that there is possibly a divergence of opinion taking place within the field of child and family social work and that the stated positions are influencing how practitioners identify and deal with risks and opportunities afforded by the Internet and social media. The suggested divergence is examined and the conclusion drawn is that what is taking place mirrors the fact that the introduction of any new technology inevitably brings with it division and debate. In seeking to understand the reaction to digital technology, consideration is given to a series of wider social discourses on childhood and risk, which includes the controversial notion that the profession is a harbinger of moral panic and that the management of risk has been broadened from child protection to child safety. The discussion paper concludes by calling for child and family social work practitioners to have a balanced debate that needs to be informed not only by current research but also by an open and honest discussion about personal use and an acknowledgement that there will be difficult moral and ethical questions to work through.     

Reasoning Together Through Telling Stories: How People Talk about Social Controversies

Qualitative Sociology - We use focus groups of ordinary citizens talking about social controversies to analyze the role of storytelling in collective reasoning. Prior research has emphasized...     

Snake parasitism in an urban old-growth forest

Urban-associated changes can have immediate or long-term consequences on animal populations. Such changes may be assessed through parasite prevalence and abundance in wildlife hosts, as urbanization can influence parasitism and disease transmission in wildlife. Snakes are widespread and diverse vertebrates that often persist in urban environments; however, parasitism of snakes in urban environments has yet to be studied, leaving the roles of snakes in parasite transmission uncharacterized. Field ecology, microscopy, molecular techniques, and geographic information science (GIS) were integrated to characterize parasitism of snakes in an urban old-growth forest park. The species, sex, mass, length, location, and prevalence of ecto-, hemo-, and fecal parasites were determined for 34 snakes of 6 species. Ectoparasites (mite), hemoparasites (Hepatozoon spp.), and fecal parasites (Entamoeba spp., Trichomonas spp., Strongloides spp., and an unidentified helminth) were detected in snakes and 64.7?% of snakes were infected by at least one of these parasites. Parasite infections were generally not related to the sex, age, or body condition of snakes. The locations of infected snakes were used to produce risk maps indicating where parasite prevalence is predicted to be greatest. The analysis of these maps indicated that snakes with fecal parasites were closer than non-infected snakes to the edge of the forest. This study confirms that snakes may be important parasite hosts or reservoirs in parasite transmission pathways in urban environments and it provides an integrative multidisciplinary approach that may be used to monitor parasitism dynamics in other urban wildlife areas.     

Accounting for Uncertainty in Heteroscedasticity in Nonlinear Regression

Toxicologists and pharmacologists often describe toxicity of a chemical using parameters of a nonlinear regression model. Thus estimation of parameters of a nonlinear regression model is an important problem. The estimates of the parameters and their uncertainty estimates depend upon the underlying error variance structure in the model. Typically, a priori the researcher would not know if the error variances are homoscedastic (i.e., constant across dose) or if they are heteroscedastic (i.e., the variance is a function of dose). Motivated by this concern, in this paper we introduce an estimation procedure based on preliminary test which selects an appropriate estimation procedure accounting for the underlying error variance structure. Since outliers and influential observations are common in toxicological data, the proposed methodology uses M-estimators. The asymptotic properties of the preliminary test estimator are investigated; in particular its asymptotic covariance matrix is derived. The performance of the proposed estimator is compared with several standard estimators using simulation studies. The proposed methodology is also illustrated using a data set obtained from the National Toxicology Program.     

The influence of religiosity on charitable behavior: A COPPS investigation

We examine the role of religion in charitable giving and find that the religious preference of both the donor and the recipient organization influence giving behavior. By exploiting a panel survey of charitable giving, we demonstrate that traditional empirical analysis on charitable giving masks important differences among donor groups. Religious giving by religious individuals is least responsive to changes in price and income, while secular giving by secular individuals has the greatest sensitivity.     

Longitudinal Links between Adolescent and Peer Conduct Problems and Moderation by a Sensitivity Genetic Index

The most extensively studied influence on adolescent conduct problem behaviors is peers, and the literature points to genetics as one source of individual differences in peer influence. The purpose of this study was to test the hypothesis that an environmental sensitivity genetic index comprised of DRD4, 5‐HTTLPR, and GABRA2 variation would moderate the association between peer and adolescent conduct problems. Latent growth modeling was applied to PROSPER project longitudinal data from adolescents and their peers. Results showed the hypothesis was supported; adolescents with more copies of putative sensitivity alleles were more strongly influenced by their peers. The interaction form was consistent with differential susceptibility in follow‐up analyses. Strengths and weaknesses of genetic aggregates for sensitivity research are discussed.