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101.
Irene Esteban-Cornejo Sonia Gómez-Martínez Carlos M. Tejero-González Ruth Castillo Ricardo Lanza-Saiz German Vicente-Rodríguez 《Journal of sports sciences》2013,31(17):1596-1603
AbstractThe aim of this report was to examine the associations between some characteristics (i.e., structure and number) of extracurricular physical activity (EPA) and cognitive performance in adolescents. A total of 1662 adolescents (880 girls; 13.0–18.5 years) from 5 Spanish cities (Granada, Madrid, Murcia, Santander and Zaragoza) were included in this study. Structure (organised and non-organised) and number of EPAs, and participation at vigorous intensity during EPA were self-reported. Cognitive performance (verbal, numeric and reasoning abilities, and an overall score) was measured with the “SRA-Test of Educational Ability”. Results showed that vigorous EPA was positively associated with all cognitive variables. Adolescents who practiced an organised EPA had higher scores in 3 of the 4 cognitive variables than those who practiced a non-organised EPA (all P < 0.05). Likewise, the group who participated in more than one EPA had higher cognitive performance in all variables than the group who participated in only one EPA (all P < 0.05). Regardless of potential confounder variables, including vigorous EPA, both structure and number of EPAs were each other independently associated with cognitive performance. Therefore, structure and number of EPAs may positively influence cognitive performance in adolescents. Participating in multiple, organised EPA may have benefits for cognitive performance. 相似文献
102.
Bianca Miarka Rubiana Cury Ricardo Julianetti Rafael Battazza Ursula Ferreira Julio Michel Calmet 《Journal of sports sciences》2013,31(16):1529-1538
AbstractThe aim of the study was to verify differences between age groups of female judo matches in time-motion and technical–tactical analysis. The sample was composed of pre-cadet (13–14 years, n = 148), cadet (15–16 years, n = 228), junior (17–19 years, n = 104) and senior (>20 years, n = 237) groups. The time-motion indicators consisted of total combat time, standing combat time, displacement without contact, gripping time, total time of techniques, groundwork combat time and pause time, per match and by each combat/pause cycle. Technical and tactical variables were also collected. The one-way analysis of variance and a post hoc test were conducted, P ≤ 0.05. Cadets, with a median of 7 (2, 12), had a number of combat/pause cycles different from junior, with 3 (1, 8.5). Regarding time-motion per match and per cycle, senior had longer total combat time, standing combat time and gripping time than other groups. Senior presented lower frequency of leg techniques than pre-cadet, cadet and junior. Time-motion and technical–tactical variables effects in female judo athletes emphasise the difference between seniors and other groups. 相似文献
103.
ABSTRACTThis study aimed to determine the influence of biological sex on intestinal injury, permeability, gastrointestinal symptoms, and systemic cytokine profile in response to exertional-heat stress. Male (n= 13) and eumenorrheic female (n= 11) endurance runners completed 2 h running at 60% V?O2max in 35°C. Blood samples were collected pre- and post-exercise and during recovery to determine plasma intestinal fatty-acid binding protein (I-FABP) and systemic cytokine profile. Urinary lactulose:L-rhamnose ratio was used to determine small intestine permeability. I-FABP increased 479% pre- to post-exercise (p< 0.001), with no difference between sexes (p= 0.432). No differences between sexes were observed for small intestine permeability (p= 0.808), gut discomfort, total, upper- and lower-gastrointestinal symptoms. However, males reported significantly higher flatulence (p= 0.049) and abdominal stitch (p= 0.025) compared to females. IL-6, IL-8, IL-10 and IL-1ra increased pre- to post-exercise (p< 0.05), with no difference between sexes. However, IL-1β increased post-exercise in males only, and was higher in males compared to females (p= 0.044). Findings suggest that when females are in the follicular phase of the menstrual cycle, biological sex has no effect on intestinal epithelial injury and permeability, and minimal effect on gastrointestinal symptoms and systemic cytokine profile in response to exertional-heat stress. 相似文献
104.
Pedro Nuno Teixeira Vera Rocha Ricardo Biscaia Margarida Fonseca Cardoso 《Higher Education》2012,63(3):337-352
The expansion of higher education systems has often been associated with the need for increasing diversification, namely at
the program level, based on the pressures to adapt more general programmes to a more diverse student population and multiple
regional, social, and economic needs. This paper explores empirically the question of programme diversity by drawing on the
Portuguese higher education’ experience, which presented massive expansion during the last decades and significant institutional
competition in recent years. The study provides a longitudinal approach and analyzes in detail the evolution of diversification
and specialization of the public and private sectors, as well as the university and polytechnic subsectors. The analysis aims
at helping to illustrate the relevance of analysing diversity from an empirical point of view and its contribution to our
understanding of the complex relationships between competition and diversity in contemporary higher education. 相似文献
105.
Ricardo Lopes Coelho 《Science & Education》2012,21(9):1337-1356
There has been much research on principles and fundamental concepts of mechanics. Problems concerning the law of inertia, the concepts of force, fictitious force, weight, mass and the distinction between inertial and gravitational mass are addressed in the first part of the present paper. It is argued in the second that the law of inertia is the source of these problems. Consequences drawn from the law explain the metaphysical concept of force, the problematic concept of fictitious force, the nominal definition of weight and the difficulty with defining mass operationally. The core of this connection between the law and these consequences lies in the fact that acceleration is a sufficient condition for force. The experimental basis of the law in the course of its history shows, however, that the law presupposes acceleration necessarily whereas acceleration does not presuppose the law. Therefore, there is no inconvenience in taking acceleration independently of the law. This is enough to bypass those problems. Taking into account how force is measured by force meters and how mass is basically determined, by comparison with the standard mass, a minimal meaning for both concepts of force and mass is established. All this converges with several solutions proposed in the course of history and increases the communicability of mechanics, as outlined in the final part of this paper. 相似文献
106.
This study examined the joint effects of home environment and center-based child care quality on children's language, communication, and early literacy development, while also considering prior developmental level. Participants were 95 children (46 boys), assessed as toddlers (mean age = 26.33 months; Time 1) and preschoolers (mean age = 68.71 months; Time 2) and their families. At both times, children attended center-based child care classrooms in the metropolitan area of Porto, Portugal. Results from hierarchical linear models indicated that home environment and preschool quality, but not center-based toddler child care quality, were associated with children's language and literacy outcomes at Time 2. Moreover, the quality of preschool classrooms moderated the association between home environment quality and children's language and early literacy skills – but not communication skills – at Time 2, suggesting the positive cumulative effects of home environment and preschool quality. Findings further support the existence of a detrimental effect of low preschool quality on children's language and early literacy outcomes: positive associations among home environment quality and children's developmental outcomes were found to reduce substantially when children attended low-quality preschool classrooms. 相似文献
107.
Ricardo Trumper 《International Journal of Science Education》2013,35(11):1111-1123
Junior high school students' astronomy conceptions were analysed by means of a written questionnaire presented to them during the beginning of the first semester. The main findings were as follows: almost half of the students indicated that the cause of the day-night cycle is the Earth spinning on its axis; most students chose as their best account for changes in the Moon's phases the Moon moving around the Earth. Despite that, most students thought that the Moon must be in its Full phase for there to be a total solar eclipse; most students underestimated the distances in the Universe and overestimated the Earth's diameter. A great proportion of students indicated that the reason for the different seasons is the tilt of the Earth's axis relative to the plane of its orbit as it revolves around the Sun. But almost the same number of students chose the varying distance between Sun and Earth or between the Earth, Moon and Sun, as a reason for the seasons. Only a third of the students answered correctly that in Israel's latitude, north of the Tropic of Cancer, the Sun is never directly overhead at noon; most students chose the correct estimate of a month for the Moon revolving around the Earth and a year for the Moon going around the Sun; about a third of the students chose the correct answer that when it is noon in Haifa, it would be about sunset in Beijing (90° east of Haifa). Few students indicated that the fact that we always see the same side of the Moon from the Earth implies that the Moon rotates on its axis once a month. 相似文献
108.
ResumenEn este trabajo se investigan dos procedimientos de reducción de las conductas autopunitivas que frecuentemente presentan los niños autistas. El primer procedimiento consiste en el reforzamiento de respuestas incompatibles con estas conductas, lográndose así una franca disminución en su frecuencia. El segundo procedimiento parte del supuesto (comprobado en el análisis conductual) que las autopuniciones representan una respuesta de escape ante la ansiedad generada por determinadas situaciones; de este modo, el procedimiento va encaminado a la reducción, o eliminación, de esta ansiedad situacional mediante la técnica de la desensibilización sistemática «in vivo», dando como resultado la eliminación total de las conductas autopunitivas ante estas situaciones, y a más largo plazo, su erradicación del repertorio conductual del sujeto. 相似文献
109.
Ricardo Cuevas Onofre Contreras Tomás García-Calvo Juan-Carlos Pastor 《Infancia y Aprendizaje》2013,36(2):248-277
AbstractThe reduction of racial prejudice is an important challenge of intercultural education. Thus, the aim of this study was to analyze racial prejudice, as well as the different profiles and the possible educational implications in secondary school students. A total of 327 third form students completed the scales of blatant and subtle prejudice and also a scale of emotions towards North Africans. The results showed significant levels of subtle prejudice and four profiles of racial prejudice, with a low number of students showing equalitarian tendencies. A multivariate analysis showed significant differences in prejudice depending on social distance as well as the academic level of the participants’ families. Finally, we discuss the results from the perspective of intercultural education and we suggest some lines of intervention in order to promote the integration of students from different cultures. 相似文献
110.
Xiao Zhang Dongrui Wu Lieyun Ding Hanbin Luo Chin-Teng Lin Tzyy-Ping Jung Ricardo Chavarriaga 《国家科学评论(英文版)》2021,8(4)
An electroencephalogram (EEG)-based brain–computer interface (BCI) speller allows a user to input text to a computer by thought. It is particularly useful to severely disabled individuals, e.g. amyotrophic lateral sclerosis patients, who have no other effective means of communication with another person or a computer. Most studies so far focused on making EEG-based BCI spellers faster and more reliable; however, few have considered their security. This study, for the first time, shows that P300 and steady-state visual evoked potential BCI spellers are very vulnerable, i.e. they can be severely attacked by adversarial perturbations, which are too tiny to be noticed when added to EEG signals, but can mislead the spellers to spell anything the attacker wants. The consequence could range from merely user frustration to severe misdiagnosis in clinical applications. We hope our research can attract more attention to the security of EEG-based BCI spellers, and more broadly, EEG-based BCIs, which has received little attention before. 相似文献