Back propagation neural networks and multiple regressions in the case of heteroskedasticity

This paper compares the performance between regression analysis and a clustering based neural network approach when the data deviates from the homoscedasticity assumption of regression. Heteroskedasticity is a problem that arises in linear regression due to the unequal error variances. One of the methods to deal heteroskedasticity in classical regression theory is weighted least-square regression (WLS). In order to deal the problem of heteroskedasticity, backpropagation neural network is applied. In this context, an algorithm is proposed which is based on robust estimates of location and dispersion matrix that helps in preserving the error assumption of the linear regression. Analysis is carried out with appropriate designs using simulated data and the results are presented.     

Likelihood procedure for testing changes in skew normal model with applications to stock returns

The skew normal distribution family is an attractive distribution family due to its mathematical tractability and inclusion of the normal distribution as the special case. It has wide applications in many applied fields such as finance, economics, and medical research. Such a distribution family has been studied extensively since it was introduced by Azzalini in 1985 Azzalini, A. (1985). A class of distributions which includes the normal ones. Scandinavian Journal of Statistics 12:171–178. [Google Scholar] for the first time. Yet, few work has been done on the study of change point problem related to this distribution family. In this article, we propose the likelihood ratio test (LRT) to detect changes in the parameters of the skew normal distribution associated with some asymptotic results of the test statistic. Simulations have been conducted under different scenarios to investigate the performance of the proposed method. Comparisons to some other existing method indicate the comparable power of the method in detecting changes in parameters of the skew normal distribution model. Applications on two real data: Brazilian and Tanzanian stock returns illustrate the detection procedure.     

t-Type corrected-loss estimation for error-in-variable model

In this article, we consider a linear model in which the covariates are measured with errors. We propose a t-type corrected-loss estimation of the covariate effect, when the measurement error follows the Laplace distribution. The proposed estimator is asymptotically normal. In practical studies, some outliers that diminish the robustness of the estimation occur. Simulation studies show that the estimators are resistant to vertical outliers and an application of 6-minute walk test is presented to show that the proposed method performs well.     

A general long-term aging model with different underlying activation mechanisms: Modeling,Bayesian estimation,and case influence diagnostics

In this paper we propose a general cure rate aging model. Our approach enables different underlying activation mechanisms which lead to the event of interest. The number of competing causes of the event of interest is assumed to follow a logarithmic distribution. The model is parameterized in terms of the cured fraction which is then linked to covariates. We explore the use of Markov chain Monte Carlo methods to develop a Bayesian analysis for the proposed model. Moreover, some discussions on the model selection to compare the fitted models are given, as well as case deletion influence diagnostics are developed for the joint posterior distribution based on the ψ-divergence, which has several divergence measures as particular cases, such as the Kullback–Leibler (K-L), J-distance, L₁ norm, and χ²-square divergence measures. Simulation studies are performed and experimental results are illustrated based on a real malignant melanoma data.     

Do Some Students Need Special Protection From Research on Sex and Trauma? New Evidence for Young Adult Resilience in “Sensitive Topics” Research

Institutional review boards (IRBs) have expressed concerns that certain individuals or groups, such as participants who are younger, ethnic minorities, or who have certain psychological or personality traits, may be particularly distressed when participating in “sensitive topics” research. This study examined the effects of several demographic and individual difference factors (i.e., age, sex, ethnicity, religiosity, Big Five personality traits, and baseline psychological distress levels) on reactions to participation in sensitive topics research. Participants were 504 undergraduates who completed an extensive battery of either trauma/sex questionnaires or cognitive tests and rated their positive and negative emotional reactions and the perceived benefits and mental costs of participating. They also compared research participation to normal life stressors. Our findings indicated that individual difference and demographic risk factors do not increase participant distress after participating in sex/trauma research over and above that experienced after participating in traditionally minimal-risk cognitive tasks. Participants generally found research participation less distressing than normal life stressors and even enjoyable.     

Indian Country Poverty: Place‐Based Poverty on American Indian Territories, 2006–10

This article examines place‐based poverty in Indian Country, emphasizing that reservation characteristics are influenced by the system of federal Indian policy that affects American Indian self‐determination and antipoverty strategies within reservation boundaries. Using data from the American Community Survey five‐year file, 2006–10, I model poverty rates using multivariate, nested regression along key dimensions associated with American Indian antipoverty strategies and place‐based poverty. The results indicate that rates of female‐headed households and opportunity structures, such as lack of work, contribute to higher rates of reservation poverty while gaming acts as a slight buffer against poverty. Surprisingly, natural‐resource‐related occupations, thought to be associated with expropriation of tribal resources, was not associated with higher poverty, while self‐governance compacts, acting as a proxy for tribal autonomy, had no significant impact on poverty rates. As tribal governments seek to address poverty through strategies enabled by self‐determination policies, there is a critical need for more comprehensive and reliable data to understand how and whether tribal governments can effectively adapt federal policies to specific reservation conditions.     

Continuity and Change in the Family System Across the Transition from Adolescence to Emerging Adulthood

As adolescents move into emerging adulthood, their social networks shift toward a focus on peers and romantic partners, yet parents and siblings remain important sources of support. The present review takes a family systems approach to integrate the growing body of literature examining longitudinal continuity and change in both positive (e.g., intimacy, support) and negative (e.g., conflict, rivalry) qualities of parent–child and sibling relationships as adolescents transition to emerging adulthood. In general, contact with family members decreases, yet the quality of family relationships appears to improve or, at the very least, stabilize across this transition. These pathways are interpreted within the lens of several prominent theories, and a discussion of the limitations of the current literature and ideas for future research are presented.     

LGBT Family Lawyers and Same-Sex Marriage Recognition: How Legal Change Shapes Professional Identity and Practice

ABSTRACT

Lawyers who practice family law for LGBT clients are key players in the tenuous and evolving legal environment surrounding same-sex marriage recognition. Building on prior research on factors shaping the professional identities of lawyers generally, and activist lawyers specifically, I examine how practice within a rapidly changing, patchwork legal environment shapes professional identity for this group of lawyers. I draw on interviews with 21 LGBT family lawyers to analyze how the unique features of LGBT family law shape their professional identities and practice, as well as their predictions about the development of the practice in a post-Obergefell world. Findings reveal that the professional identities and practice of LGBT family lawyers are shaped by uncertainty, characteristics of activist lawyering, community membership, and community service. Individual motivations and institutional forces work to generate a professional identity that is resilient and dynamic, characterized by skepticism and distrust coupled with flexibility and creativity. These features are likely to play a role in the evolution of the LGBT family lawyer professional identity post-marriage equality.     

Country-Level Investment in Cultural Opportunity Structures. A Potential Source of Health Differences Between 21 European Countries

Individual’s participation in cultural activities may positively affect health through a pathway mediated by social capital. We examine whether country-level investment in cultural opportunity structures was associated with between-country differences in self-rated health and, if so, whether these associations were mediated by citizens’ confidence in societal institutions, i.e., by institutional trust, regarded as a dimension of social capital. For 24,887 respondents in the European Social Survey, 2006, data on self-rated health, institutional trust (individual-level and country-level), and sociodemographic variables were linked with statistics-based country-level data on 10 indicators of cultural opportunity structures and mediator variables (gross domestic product (GDP), Gini index, and welfare state regime). Over and above the sociodemographics, six cultural indicators contributed to between-country health differences in logistic multilevel regression analysis: the percentage of arts students, the RC index, the percentage of writers and creative artists of total employment, exports of cultural goods, imports of cultural goods, and the number of feature films produced per capita. Controlling, furthermore, for trust, and country-level mediators, only imports of cultural goods contributed to between-country differences in health. No associations with other cultural indicators remained after controlling for GDP or welfare state regime. Institutional trust may partially mediate the significance of cultural investments for self-rated health. However, both cultural investment and trust may be concomitants of general prosperity and welfare policies. Future studies should investigate whether the countries’ welfare policies influence the transformation of cultural investment into institutional trust and which types of indicators best depict associations between investments and health.