Postural assessment of school children: an input for the design of furniture

During the last decades of the previous century, school desks with a tilt top have disappeared. The chairs have been designed for sitting upright, with the hip, knees and ankles all at right angles. However, the erect posture cannot be maintained for more than one or two minutes, after which it will result in fatigue, discomfort or poor posture. The main aim of project is to identify the type of furniture that most effectively contribute to adequate neck and back postures of the school children, by carrying out a postural analysis of a sample of school pupils when using three different types of furniture. The postures adopted by school pupils were monitored by video during several activities, such as reading, writing and painting tasks, copying from a blackboard and listening the teacher. Additionally, the characteristics of the adopted postures were assessed by registering the head tilt, flexion of the neck, trunk and hips position. All these aspects were classified and the results were recorded for future analysis. The obtained results seem to point out that the use of a school desk with a tilted table surface resulted in a reduction in trunk and neck flexion, preserving the natural lordosis in the lumbar and cervical regions. Accordingly, it can be concluded that there are alternatives to consider in the furniture design in order to eliminate tensions and, consequently, to improve children's wellbeing.     

Relationships Between Religiosity Level and Attitudes Toward Lesbians and Gay Men Among Turkish University Students

This study examined the relationships between religiosity levels and attitudes toward lesbians and gay men among freshmen university students in Turkey. The Attitudes Towards Lesbians and Gay Men Scale–Short Form and the Religiosity Scale were administered to 91 male (M = 19.95, SD = 1.48 years) and 171 female (M = 19.23, SD = 1.28 years) students. The findings showed that male freshmen (M = 19.32, SD = 4.97) had more negative attitudes toward gay men than toward lesbians (M = 17.84, SD = 5.25), p = .000. In addition, attitudes of male freshmen were significantly more negative toward gay men (M =19.32, SD = 4.97) than females (M = 17.51, SD = 5.73), p = .012. Both male and female freshmen students who had higher levels of religiosity were found to have higher levels of negative attitudes toward both lesbians and gay men.     

The Characteristics of Child Sexual Abuse in the School Environment in Turkey

School may represent a protective factor, boosting the mental health of the student body, while also representing a risk factor that heightens the potential for mental health problems. The present study aims to identify the individual and familial characteristics associated with the incidents of child sexual abuse (CSA) in Turkey’s school environment. The incidents involving school-related CSA constituted 5.6% (N = 125) of 2,238 cases. The following was discovered: an adult committed the majority (64%) of CSA in the school environment; most adult perpetrators were teachers (62.5%). This study determined that the perpetrators manipulated the victims via methods that included physical abuse (11.2%), threats (19.2%), tricks/deception (15.2%), and taking photographs/videos with sexual content (3.2%); and CSA incidents involved intercourse (15.2%); and almost three-quarter of the victims of CSA in the school environment reported the incident late. This study indicates that peer perpetrators abuse younger victims and a greater proportion of male victims relative to adult perpetrators. In light of these findings, school security must be improved, especially in public schools, and trainings aimed at preventing bullying and sexual abuse (SA) should be given to all school staff, students, and parents.     

The post-Macy paradox,information management and organising: Good intentions and a road to hell?

Between 1946 and 1953, leading scientists met in New York in the context of the so-called Macy conferences, often linked to the emergence of cybernetics. They hankered for a new vision of mind and society. The traumatism of WW2 was implicit but omnipresent, and the Cold War was beginning. Macy key tools and concepts about information, the value of information, and computer artefacts have finally produced a new world, in particular an organisational world, which is far removed from their original dreams. Organisational members are now involved in difficult situations in terms of organising, that is, new modes of performativity which are difficult to comprehend and deal with; a transformation of meaning and knowledge in collective activity; and a threat to well-being and happiness as mental activities, cognition and bodies are increasingly disconnected. We use the Macy conferences as an entry point to reflect on the ‘longue durée’ evolution of the material underpinnings of information and their relationship with organising. We first explore the new conceptualisations at the core of the Macy conferences, information, value of information, and computer artefacts. We then put the Macy conferences into a socio-historical perspective by means of two theoretical approaches, iconographical and semiotic; this involves a historical comparison between the ‘screen-images’ or our Information Age and the ‘object-images’ of medieval cathedrals. We show that there are important disruptions in organising grounded in a new semiosis, which emerged over the longue durée of collective activity, and was articulated further during the Macy conferences. We describe this long-term evolution as the post-Macy paradox.     

Sampling and empirical risk minimization

ABSTRACT

In certain situations that shall be undoubtedly more and more common in the Big Data era, the datasets available are so massive that computing statistics over the full samples is hardly feasible, if not unfeasible. A natural approach in this context consists in using survey schemes and substituting the ‘full data’ statistics with their counterparts based on the resulting random samples, of manageable size. It is the main purpose of this paper to investigate the impact of survey sampling on statistical learning methods based on empirical risk minimization through the standard binary classification problem, considered here as a ‘case in point’. Precisely, we prove that, in presence of auxiliary information, appropriate use of optimally coupled Poisson survey plans may not affect much the learning rates, while possibly reducing significantly the number of terms that must be averaged to compute the empirical risk functional with overwhelming probability. These striking results are next shown to extend to more general sampling schemes by means of a coupling technique, originally introduced by Hajek [Asymptotic theory of rejective sampling with varying probabilities from a finite population. Ann Math Stat. 1964;35(4):1491–1523].     

Parameter estimation of the flexible Weibull distribution for type I censored samples

Often in practice one is interested in the situation where the lifetime data are censored. Censorship is a common phenomenon frequently encountered when analyzing lifetime data due to time constraints. In this paper, the flexible Weibull distribution proposed in Bebbington et al. [A flexible Weibull extension, Reliab. Eng. Syst. Safety 92 (2007), pp. 719–726] is studied using maximum likelihood technics based on three different algorithms: Newton Raphson, Levenberg Marquardt and Trust Region reflective. The proposed parameter estimation method is introduced and proved to work from theoretical and practical point of view. On one hand, we apply a maximum likelihood estimation method using complete simulated and real data. On the other hand, we study for the first time the model using simulated and real data for type I censored samples. The estimation results are approved by a statistical test.     

Some contributions on the multivariate Poisson–Skellam probability distribution

In this article, we introduce a new form of distribution whose components have the Poisson or Skellam marginal distributions. This new specification allows the incorporation of relevant information on the nature of the correlations between every component. In addition, we present some properties of this distribution. Unlike the multivariate Poisson distribution, it can handle variables with positive and negative correlations. It should be noted that we are only interested in modeling covariances of order 2, which means between all pairs of variables. Some simulations are presented to illustrate the estimation methods. Finally, an application of soccer teams data will highlight the relationship between number of points per season and the goal differential by some covariates.     

Non linear parametric mode regression

In this article, we propose a semi-parametric mode regression for a non linear model. We use an expectation-maximization algorithm in order to estimate the regression coefficients of modal non linear regression. We also establish asymptotic properties for the proposed estimator under assumptions of the error density. We investigate the performance through a simulation study.