Non-informative priors for the common mean in the one-way random effects model with heterogeneous error variances

The paper develops some objective priors for the common mean in the one-way random effects model with heterogeneous error variances. We derive the first and second order matching priors and reference priors. It turns out that the second order matching prior matches the alternative coverage probabilities up to the second order, and is also an HPD matching prior. However, derived reference priors just satisfy a first order matching criterion. Our simulation studies indicate that the second order matching prior performs better than the reference prior and the Jeffreys prior in terms of matching the target coverage probabilities in a frequentist sense. We also illustrate our results using real data.     

Bayesian model selection for life time data under type II censoring

This paper considers the Bayesian model selection problem in life-time models using type-II censored data. In particular, the intrinsic Bayes factors are calculated for log-normal, exponential, and Weibull lifetime models using noninformative priors under type-II censoring. Numerical examples are given to illustrate our results.     

A multidimensional approach to the generation of helmets' design criteria: a preliminar study

The design and development process of helmets incorporates systematically design criteria related to safety to accomplish European and local standards for the commercialization. However, there are few studies focused on user's comfort and adaptation. Present study tackles a multidimensional approach to gain better understanding of the interaction between helmet and user to generate design criteria for the internal helmet surface. Morphological characteristics of the target population, pressure distribution over head and subjective perception of fitting and discomfort are the factors considered to establish the criteria that assure a proper fit. Ten men corresponding to helmet size M and usual drivers of motorbike wore two helmet models in three sizes (S, M and L). The head shape of participants was acquired using the head scanner of I-Ware laboratory and an instrumented pad was used to measure pressure in five head regions. After wearing the helmet, users filled in a perception questionnaire about fitting, comfort and usability considering the five regions. Users' fitting perception provided the relation between pressure levels and the comfort felt in the five regions. This study constitutes a first approach to a new methodology to generate criteria to improve the design of helmets under a multidimensional approach.     

Furniture dimensions and postural overload for schoolchildren's head, upper back and upper limbs

The aim of this study was to evaluate how the fixed furniture dimensions match with students' anthropometry and to describe head, upper back and upper limbs postures and movements. Evaluation was performed in 48 students from a Brazilian state school. Furniture dimensions were measured with metric tape, movements and postures by inclinometers (Logger Tecknologi, ?karp, Sweden). Seat height was high for 21% and low for 36% of the students; seat length was short for 45% and long for 9% and table height was high for 53% and low for 28%. Regression analysis showed that seat/popliteal height quotient is explained by 90th percentile of upper back inclination (β=0.410) and 90th percentile of right upper arm elevation (β=-0.293). For seat/thigh length quotient the significant variables were 90th percentile of upper back velocity (β=-0.282) and 90th percentile of right upper arm elevation (β=0.410). This study showed a relationship between furniture mismatch and postural overload. When the seat height is low students increase upper back left inclination and right upper arm elevation; when the seat is short students decrease the upper back flexion velocity and increase right upper arm elevation.     

Bullying in schools: what is the problem, and how can educators solve it?

This chapter reviews recent research on bullying from an educator's perspective. It is well known that bullying, a serious issue in schools, can be prevented when educators intervene. But research has shown that it is difficult for educators to detect bullying situations in their school and intervene competently and effectively. This chapter examines how educators can detect bullying, how they can best tackle serious cases of bullying, and how they can best prevent bullying in the long run.     

University Students’ Sense of Belonging to the Home Town: The Role of Residential Mobility

In the study of young people’s relationships with residential contexts, it is important to consider the role of developmental tasks (e.g. identity construction, academic and professional choices, etc.) in influencing Place Identity and Sense of Community. Residential mobility may represent an adaptive strategy for modifying some aspects of one’s identity and a contributing factor to the development of autonomy from the family. Limited attention has been devoted to the study of the ways young people deal with their attachments to old and new places within this process. This study involved 203 university students, attending a large university in the North of Portugal. The aim was to investigate Place Identity (PI) and Sense of Community (SoC) related to the home town, and differences according to residential condition (native vs. temporary resident) and year of attendance (I vs. IV). Among students who moved, the role of motives (forced vs. voluntary) and of residential choices after graduation on PI and SoC were assessed. Results indicated that, among students who moved for academic reasons, SoC and PI related to the home town were lower and decreased from the first to the fourth year. SoC was higher among students who experienced the relocation as a forced choice. Students who anticipated to return to their home town after graduation had higher SoC and PI.     

National Culture of Indulgence as Predictor of Prosocial Behavior: Governmental Effectiveness as Boundary Condition

Previous studies of national culture and prosocial behaviors have been limited to Hofstede’s five traditional culture dimensions. We introduce the fairly new and less studied cultural dimension of indulgence versus restraint (IVR) as a predictor of prosocial behaviors. We tested the effect of IVR on prosocial behavior over Hofstede’s previously studied dimensions. We also tested the moderating effect of government effectiveness on the relationship between indulgence and prosocial behavior. We crossed data for cultural dimensions from Hofstede with data from the world-giving index for prosocial behavior and data for government effectiveness from the World Bank. In total, eighty-seven countries entered our model. Indulgence predicted volunteering above the other researched cultural dimensions. It did not predict helping a stranger or donating. Among the cultural dimensions, only uncertainty avoidance was also significant in the prediction of volunteering. Uncertainty avoidance was the only cultural dimension that predicted donating. Individualism was not significant in the prediction of prosocial behaviors. Long-term orientation was the only cultural dimension that predicted helping a stranger (but not volunteering and donating) over other researched cultural dimensions. We found that government effectiveness is a boundary condition to the link between indulgent cultures and two prosocial behaviors (donating and helping a stranger but not for volunteering). Our results indicate that only in countries with high government effectiveness does indulgence predict prosocial behaviors, and not in cultures with low government effectiveness.

     

Estimating the expected value of fuzzy random variables in random samplings from finite populations

In this paper we consider the problem of estimating the expected value of a fuzzy-valued random element in random samplings from finite populations. To this purpose, we quantify the associated sampling error by means of a parameterized measure we have introduced in a previous paper. Keywords: Aumann's integral, expected value of a fuzzy random variable, fuzzy random variable, -mean squared dispersion, random samplings, random set.