Fractal descriptors based on the probability dimension: a texture analysis and classification approach

In this work, we propose a novel technique for obtaining descriptors of gray-level texture images. The descriptors are provided by applying a multiscale transform to the fractal dimension of the image estimated through the probability (Voss) method. The effectiveness of the descriptors is verified in a classification task using benchmark over texture datasets. The results obtained demonstrate the efficiency of the proposed method as a tool for the description and discrimination of texture images.Comment: 7 pages, 6 figures. arXiv admin note: text overlap with arXiv:1205.282

Postural patterns in the first year of life: contributions of maternal physical activity in the pregnancy period

BACKGROUND: The study objective was intended to verify whether the practice of maternal physical activity during the pregnancy period could be assumed as a contribution to the acquisition of postural patterns in the child during its first year of life. METHODS: A transversal and descriptive study was carried where we recorded the developments observed in a sample of 80 Portuguese children, according to the habits and type of physical activity of the mothers. Statistical descriptive and inferential test were performed. RESULTS: The results were clearly positive in terms of temporal gains of neck tonic control, and also in the acquisition of an erect position. CONCLUSIONS: Despite the average values are not statistical significant we have observed indicators that the maternal physical activity during pregnancy apparently is a factor that can favor the child’s motor development during their first year of life, particularly in the acquisition of postural patterns.info:eu-repo/semantics/publishedVersio

La atención de los estudiantes durante la clase de educación física basada en el rendimiento académico

Attention is an important variable that can dictate the success and failure of an activity or task. This variable is characterized by the ability to direct cognitive resources to a given situation. The purpose of this research was to find patterns in the students’ attention profiles, according to their academic achievement, during the physical education class and in different sports. We used the ATEST-EF questionnaire (Petrica, 2010) in which students had to answer the question «What were you thinking the moment you heard the signal?» The study involved 156 students from the 3th cycle of basic education, aged between 12 and 16 years old ( = 14,7 ± 1,3) evaluated in four different sports taught in the discipline of physical education (athletics, gymnastics, basketball and football), and in four moments of the class. Considering our variables, we used Chi-Square and Kruskal-Wallis statistical tests. The results show that task attendance holdsthehighestpercentagevalues throughouttheclassinrelationtotheremainingcategories,regardlessoftheiracademicperformance and sport, but we observed that students with satisfactory and good academic performance have more stable values of attention regarding the students with less academic performance. We found statistical significance at the end of the class between students with good academic performance and affective attention, and among students with lower academic performance and attention to other things. Subsequently, we used the same classification to compare the profiles of attention among the four mentioned sports. We observed some patterns between team and individual sports, but did not find statistically differences, however the results suggest a positive relationship between attention and academic performance.La atención es una variable importante que puede dictar el éxito y el fracaso de una actividad o tarea. Esta variable se caracteriza por la capacidad de dirigir recursos cognitivos a una situación dada. El propósito de esta investigación fue encontrar patrones en los perfiles de atención de los estudiantes, de acuerdo con sus logros académicos, durante la clase de educación física y en diferentes deportes. Utilizamos el cuestionario ATEST-EF (Petrica, 2010) en el que los estudiantes tenían que responder la pregunta «Qué estaba pensando en el momento en que escuchó la señal?» En el estudio participaron 156 estudiantes del tercer ciclo de educación básica, con edades comprendidas entre 12 y 16 años (= 14,7 ± 1,3) evaluados en cuatro deportes diferentes que se imparten en la disciplina de educación física (atletismo, gimnasia, baloncesto y fútbol), y en cuatro momentos de la clase. Considerando nuestras variables, utilizamos las pruebas estadísticas Chi-Square y Kruskal-Wallis. Los resultados muestran que la asistencia a las tareas tiene los valores porcentuales más altos en toda la clase en relación con las categorías restantes, independientemente de su rendimiento académico y deporte, pero observamos que los estudiantes con un rendimiento académico satisfactorio y bueno tienen valores de atención más estables con respecto a los estudiantes con Menos rendimiento académico. Encontramos significación estadística al final de la clase entre estudiantes con buen rendimiento académico y atención afectiva, y entre estudiantes con bajo rendimiento académico y atención a otras cosas. Posteriormente, utilizamos la misma clasificación para comparar los perfiles de atención entre los cuatro deportes mencionados. Observamos algunos patrones entre el equipo y los deportes individuales, pero no encontramos diferencias estadísticas, sin embargo, los resultados sugieren una relación positiva entre la atención y el rendimiento académico.info:eu-repo/semantics/publishedVersio

Psychometric validation of Atest-EF and attention profile of students during physical education classes

The present study aimed for the adaptation and validation of the Questionnaire Atest-EF, with the use of a confirmatory factorial analysis (CFA) of the measurement model, applied to students of the 3rd cycle of Basic Education. A total of 156 students of both genders, aged between 12 and 16 years (M = 14.7 ± SD = 1.3) were included in the study, with 84 female and 71 males, from the 7th, 8th and 9th grade. The main results reveal that the psychometric qualities confirm the adequacy of this model, demonstrating that the Atest-EF factorial structure: 1 factor/4 items, has very acceptable indexes of Atest - EF validity: (χ2 = 6.141, p = .000, χ2/gl = 3.07, NFI = 0.90 CFI = .925, IFI = .930, MFI = .9997, GFI = .995, AGFI = .975, RMR = .042, RMSEA = .08, SRMR = .028). With these results, the structural model reveals a satisfactory factorial assessment. This led to conclude that the Portuguese version of Atest-EF can be used, with high confidence in the evaluation of the student’s attention profiles in Physical Education classes. Compared with the moments of the class, there were only significant differences in students’ attention in the approach to sports in the first and fourth moments of the class, as well as in the general profile of attention, with significantly higher values in the approach to team sports.info:eu-repo/semantics/publishedVersio

Sudden Trust Collapse in Networked Societies

Trust is a collective, self-fulfilling phenomenon that suggests analogies with phase transitions. We introduce a stylized model for the build-up and collapse of trust in networks, which generically displays a first order transition. The basic assumption of our model is that whereas trust begets trust, panic also begets panic, in the sense that a small decrease in trust may be amplified and ultimately lead to a sudden and catastrophic drop of trust. We show, using both numerical simulations and mean-field analytic arguments, that there are extended regions of the parameter space where two equilibrium states coexist: a well-connected network where confidence is high, and a poorly connected network where confidence is low. In these coexistence regions, spontaneous jumps from the well-connected state to the poorly connected state can occur, corresponding to a sudden collapse of trust that is not caused by any major external catastrophe. In large systems, spontaneous crises are replaced by history dependence: whether the system is found in one state or in the other essentially depends on initial conditions. Finally, we document a new phase, in which agents are connected yet distrustful.Comment: 15 pages, 10 figure

The strategic dimension of the use of communication technologies to support learning: the case of portuguese public higher education

This paper presents partial results from a research project about the use Portuguese Public Higher Education Institutions are doing of Communication Technologies to support education. The paper describes the project rationale and the methodology used. Some results are also presented concerning the strategic dimension of the use of Communication Technologies to support learning, and their respect to teachers and to staff with institutional responsibilities. Finally, some conclusions are also discussed

The institutional perspective on the use of communication technologies in portuguese public higher education: a research proposal

This paper presents and discusses the research rationale adopted to study the institutional perspective of the Portuguese higher education institutions as far as the use of communication technologies to support education is concerned. The paper presents the research questions, the analysis model, the methodology used and the outline of the data collection instruments eveloped. Some preliminary results are also presented and the next steps of the research project are outlined