AMEMIYA'S FORM OF THE WEIGHTED LEAST SQUARES ESTIMATOR

Amemiya's estimator is a weighted least squares estimator of the regression coefficients in a linear model with heteroscedastic errors. It is attractive because the heteroscedasticity is not parametrized and the weights (which depend on the error covariance matrix) are estimated nonparametrically. This paper derives an asymptotic expansion for Amemiya's form of the weighted least squares estimator, and uses it to discuss the effects of estimating the weights, of the number of iterations, and of the choice of the initial estimate. The paper also discusses the special case of normally distributed errors and clarifies the particular consequences of assuming normality.     

Recentering our tendencies: Immigrant youth development and the importance of context in social work research

According to Weiner’s model, help giving has various determinants such as social and individual causes, affective reactions, and responsibility. The aim of this study was (1) to examine the influence of bullying acts, the victim’s behavior at work, and revictimization on equity judgments and the perceived responsibility of perpetrators and victims; and (2) to test the determinants of help decisions. Twelve vignettes of bullying at work submitted to 133 participants varied according to the severity of bullying, the victim’s pro- or antisocial behaviors, and the victim’s antecedents. The results showed that the situation was judged less equitable, the victim less responsible, and the perpetrator more responsible, and the intention of help was increased, (1) when the perpetrator’s acts were serious, and (2) when the bullied person had shown prosocial behavior versus antisocial behavior. The help increased more (1) when the perpetrator’s acts were harmful and (2) when the victim had shown prosocial behaviors.     

Bayesian item response model: a generalized approach for the abilities' distribution using mixtures

Traditional Item Response Theory models assume the distribution of the abilities of the population in study to be Gaussian. However, this may not always be a reasonable assumption, which motivates the development of more general models. This paper presents a generalized approach for the distribution of the abilities in dichotomous 3-parameter Item Response models. A mixture of normal distributions is considered, allowing for features like skewness, multimodality and heavy tails. A solution is proposed to deal with model identifiability issues without compromising the flexibility and practical interpretation of the model. Inference is carried out under the Bayesian Paradigm through a novel MCMC algorithm. The algorithm is designed in a way to favour good mixing and convergence properties and is also suitable for inference in traditional IRT models. The efficiency and applicability of our methodology is illustrated in simulated and real examples.     

A review of inflation accounting and its economic implications

The purposes of this paper are firstly to identify the problems which inflation creates in the context of conventional accounting methods, secondly to consider the alternative forms of inflation accounting which have been proposed, thirdly to look in more detail at the particular method which is to be adopted in the UK, and finally to consider the effects which that method will have on company results and on broader economic issues.     

A bus stop shelter evaluated from the user's perspective

This study aims to evaluate the current bus stop shelter model used in Florianópolis, Brazil, through a functional analysis--focused in the relationship between the shelter, the users and their activities--and also to analyse users' perceptions. The methodology consisted of exploratory visits, anthropometric analysis, observation and interviews. The exploratory visit intended to survey the physical characteristics of the shelter (dimensions, materials, colors, displayed information) and its position on the sidewalk. The anthropometric analysis was made to verify whether the dimensions of the shelters were adequate to users' needs. The observation provided data for the analysis of users' behavior, which involved a biomechanical study of their postures, an ownership/occupancy analysis in terms of territoriality and studies about spatial requirements of interpersonal relations (proxemics). The interviews helped to analyze how the user perceives the quality of some of the main functions of the shelter: to provide physical and psychological comfort and to display information about the public transportation system. As a result, the overall conclusion is that shelters do not meet users' needs. Recommendations are provided in order to improve physical and psychological comfort and to display relevant information about the transportation system.     

Family and Couple Variables Regarding Adherence in Type 2 Diabetes Patients in the Initial Stages of the Disease

This study analyzed which family and couple variables predicted adherence to standard care treatment, in patients recently diagnosed with type 2 diabetes. The sample comprised 224 dyads assessed during the first year of diagnosis (T1) and 4 months later (T2). The results showed that family stress, dyadic adjustment, family coping, and positive support assessed by patients at T1 predicted medication adherence and glucose monitoring at T2. Positive support and dyadic adjustment, assessed by partners at T1, predicted patients' adherence to glucose monitoring and diet at T2. This study highlights the important role of the partner in patient`s adherence. Therefore, standard care in type 2 diabetes should be offered in the context of the dyad.     

A hierarchical theory of occupational segregation and wage discrimination

Becker's model of discrimination is extended to the case where men exhibit distastes for working under female managers. The distribution of women in the resulting occupational hierarchy depends on the number of women in lower occupations, the wages of male workers in lower occupations, and male distastes for female management. Thus, there exists an occupational sorting function, related to wages, that determines the occupational distribution of women. We integrate this sorting function into a standard wage equation to derive a new decomposition of male-female wage differentials and apply it to a sample of insurance industry workers from the 1988 CPS.     

Predicting burrowing owl flight trajectories in urban environments

Urban Ecosystems - It is important to understand how animals respond to changes in landscape structure, especially when considering habitat alteration and urbanization. Using the burrowing owl...     

Does control concentration affect board busyness? International evidence

Journal of Management and Governance - Previous literature suggests that shareholders can concentrate control without cash flow rights, creating incentives to expropriate firm resources. However,...