Component Models for Fuzzy Data

The fuzzy perspective in statistical analysis is first illustrated with reference to the “Informational Paradigm” allowing us to deal with different types of uncertainties related to the various informational ingredients (data, model, assumptions). The fuzzy empirical data are then introduced, referring to J LR fuzzy variables as observed on I observation units. Each observation is characterized by its center and its left and right spreads (LR₁ fuzzy number) or by its left and right “centers” and its left and right spreads (LR₂ fuzzy number). Two types of component models for LR₁ and LR₂ fuzzy data are proposed. The estimation of the parameters of these models is based on a Least Squares approach, exploiting an appropriately introduced distance measure for fuzzy data. A simulation study is carried out in order to assess the efficacy of the suggested models as compared with traditional Principal Component Analysis on the centers and with existing methods for fuzzy and interval valued data. An application to real fuzzy data is finally performed. We would like to express our gratitude to the Editor, the Associate Editor, and the Referees whose comments and suggestions improved significantly the quality of the paper.     

Gender effects among undergraduates relating to suicide risk, impulsivity, aggression and self-efficacy

The present study investigated the association of impulsivity, aggression and self-efficacy with protective factors against suicide. The study population consisted of 300 Italian university students (141 males, 159 females); mean age 24.2 (SD = 3.01). Participants were assessed by means of the Reasons for Living Inventory, the Aggression Questionnaire, the Barratt Impulsiveness Scale, and the General Self-Efficacy Scale. Correlations between reasons for living and aggression and impulsivity scores were weak. However, for those individuals with high self-efficacy, aggression and impulsivity were associated with stronger reasons for living. These results support the possibility that increasing general self-efficacy could be a useful target for interventions directed toward suicide prevention in individuals with problems in emotional control.     

Enabling Interactive Exploration of Cultural Heritage: An Experience of Designing Systems for Mobile Devices

Interaction design of mobile systems is a complex activity because it requires considering new usability and user experience aspects in order to exploit the peculiar characteristics of mobile devices, such as their pervasive and ubiquitous nature. This paper discusses issues about designing, developing and evaluating mobile systems. Italy has a rich cultural heritage, and the focus in this study is on the design of systems that enable interactive exploration of historical sites, not only for enhancing the user experience but also for learning purposes. The experience of the researchers at the Interaction, Visualisation and Usability lab, University of Bari, Italy, in designing a mobile learning system, called Explore!, which supports young students learning ancient history during a visit to archaeological parks, is reported. The evaluation of Explore! through systematic field studies shows that the adopted approach is able to transform the visit to archaeological parks into a more complete and culturally rich experience.     

Exercise is positively related to adolescents' relationships and academics.

Eighty-nine high school seniors were administered a questionnaire that gathered information on their exercise habits (ranging from rarely to daily), relationships with parents and peers, depressive tendencies, sports involvement, drug use, and academic performance. Students with a high level of exercise had better relationships with their parents (including greater intimacy and more frequent touching), were less depressed, spent more time involved in sports, used drugs less frequently, and had higher grade point averages than did students with a low level of exercise.     

Definability of directly indecomposable congruence modular algebras

It is proved that the directly indecomposable algebras in a congruence modular equational class form a first-order class provided that fulfils some two natural assumptions.Research supported by CONICOR and SECYT (UNC).Presented by W. Dziobiak     

Letter Dyslexia in a Letter-by-Letter Reader

We describe a letter-by-letter patient who produced misreading errors in both letters in isolation and in words. All errors were visual in nature. We hypothesized an access deficit to the abstract visual representation of letters that prevents letter identification. This deficit could account for the patient's letter-by-letter behavior, since each letter constituted a potential identification problem. An access deficit, moreover, could also explain the patient's letter visual errors. In access processing, in fact, the letters sharing common structural features in their abstract representations were the ones more frequently mismatched.     

Development of visuomanual tracking in 5- to 9-year-old boys

Visuomanual sinusoidal tracking is investigated in 5- to 9-year-old children. The proportion of successful performances steadily increases with age, but adult proficiency is never attained even by those who can perform the task. Moreover, the progress in proficiency—as measured by systems analysis techniques—is not monotonic and suggests the presence of distinct stages in the development of visuomotor coordination. Qualitative analysis of unsuccessful performance demonstrates that failures cannot be ascribed only to insufficient motor coordination and emphasizes the role of cognitive and representational factors even in such a simple task.