排序方式： 共有51条查询结果，搜索用时 218 毫秒
1.
Gracia-Marco L Tomas C Vicente-Rodriguez G Jimenez-Pavon D Rey-Lopez JP Ortega FB Lanza-Saiz R Moreno LA 《Journal of sports sciences》2010,28(13):1383-1389
The aims of this study were to identify differences between the sexes in extra-curricular participation in sports and to determine its association with body fat and socio-demographic factors in Spanish adolescents. A total of 2165 adolescents (1124 males and 1041 females) aged 13.0-18.5 years from the AVENA Study participated. Participants filled in an ad hoc questionnaire for extra-curricular participation in sports, which was the dependent variable. Independent variables were: age, percent body fat, and father's and mother's educational level and occupation. Chi-square tests and logistic regression were applied. Bivariate analysis showed for male adolescents that age and father's occupation were related to extra-curricular participation in sports. In addition, body fat and mother's education and occupation (all P?相似文献
2.
Innovative Higher Education - The percentage of Latinx college athletes in the National Collegiate Athletic Association (NCAA) continues to grow, yet research remains scarce on their experiences.... 相似文献
3.
M Martín-Matillas FB Ortega JR Ruiz D Martínez-Gómez G Vicente-Rodríguez A Marcos L Béghin A Kafatos M González-Gross M Zaccaria D Molnár S De Henauw M Sjöström LA Moreno MJ Castillo On Behalf Of The Helena Study 《Journal of sports sciences》2012,30(13):1329-1335
Abstract High physical fitness in childhood and adolescence is positively associated with favourable health-related outcomes. Our aim was to examine the relationship between relatives' (father, mother, brother, sister, and best friend) physical activity engagement and encouragement on adolescents' physical fitness. Adolescents were part of the HELENA study, a multi-centre study conducted in 10 cities from nine European countries in 2006-2008. Participants were 3288 adolescents (48% boys, 52% girls) aged 12.5-17.5 years with valid data on at least one of the three fitness variables studied: muscular strength (standing long jump), speed/agility (4×10 m shuttle run), and cardiorespiratory fitness (20 m shuttle run). The adolescents reported their relatives' physical activity engagement and encouragement. Analysis of covariance showed that relatives' physical activity engagement (father, mother, brother, and best friend) was positively related to cardiorespiratory fitness (P?相似文献
4.
The aim of this paper is to characterize the distribution of number of hits and spent time by web session. It also expects to find if there are significant differences between the length and the duration of a session with regard to the point of access–search engine, link or root. Web usage mining was used to analyse 17,174 web sessions that were identified from the webometrics.info web site. Results show that both distribution of length and duration follow an exponential decay. Significant differences between the different origins of the visits were also found, being the search engines’ users those who spent most time and did more clicks in their sessions. We conclude that a good SEO policy would be justified, because search engines are the principal intermediaries to this web site. 相似文献
5.
Evdokimova Olga L. Alves Carla S. Krsmanović Whiffen Radenka M. Ortega Zaida Tomás Helena Rodrigues João 《Journal of Zhejiang University. Science. B》2021,22(6):450-461
In this study, the fibers of invasive species Agave americana L. and Ricinus communis L. were successfully used for the first time as new sources to produce cytocompatible and highly crystalline cellulose nanofibers. Cellulose nanofibers were obtained by two methods, based on either alkaline or acid hydrolysis. The morphology, chemical composition, and crystallinity of the obtained materials were characterized by scanning electron microscopy(SEM) together with energy-dispersive X-ray spectroscopy(EDX), dynamic light scattering(DLS), X-ray diffraction(XRD), and Fourier transform infrared(FTIR)spectroscopy. The crystallinity indexes(CIs) of the cellulose nanofibers extracted from A. americana and R. communis were very high(94.1% and 92.7%, respectively). Biological studies evaluating the cytotoxic effects of the prepared cellulose nanofibers on human embryonic kidney 293 T(HEK293 T) cells were also performed. The nanofibers obtained using the two different extraction methods were all shown to be cytocompatible in the concentration range assayed(i.e., 0-500 μg/mL). Our results showed that the nanocellulose extracted from A. americana and R. communis fibers has high potential as a new renewable green source of highly crystalline cellulose-based cytocompatible nanomaterials for biomedical applications. 相似文献
6.
The importance of a scientific journal is usually established by considering the number of citations received by the papers that the journal publishes. In this way, the number of citations received by a scientific journal can be considered as a measure of the total production of the journal. In this paper, in order to obtain measures of the efficiency in the production process, the approach provided by stochastic frontier analysis (SFA) is considered, and econometric models are proposed. These models estimate a frontier production, which is the maximum achievable number of citations to the journal based on its resources. The efficiency can then be measured by considering the difference between the actual production and the estimated frontier. This approach is applied to the measurement of the productive efficiency of the journals of the JCR social sciences edition database, which belong simultaneously to the areas of “economics” and “social sciences, mathematical methods”. 相似文献
7.
José Eugenio Ortega Jaime Iglesias José Miguel Fernández José Antonio Corraliza 《Infancia y Aprendizaje》2013,36(21):83-96
ResumenEl presente informe analiza la expresión emocional de los ciegos congénitos mediante una codificación muscular de los movimientos faciales. Esta expresión, de carácter más involuntario, es semejante a la de los videntes. En cambio, los sujetos invidentes tienen una expresividad menor y menos diferenciada en las poses voluntarias. Los resultados, que confirman los hallazgos de autores anteriores, apoyan la existencia de dos fuentes de información en el desarrollo emocional: una de naturaleza genética, que explicaría las semejanzas en la expresión emocional o involuntaria, y otra ambiental, que daría cuenta de las diferencias en la expresión voluntaria. Por último, se plantean las consecuencias de este trabajo para las distintas disciplinas psicológicas. 相似文献
8.
José Luis Ortega 《Infancia y Aprendizaje》2013,36(21):97-121
RESUMENSe presenta un modelo de educación especial basado en un enfoque sistemático de la enseñanza. La aplicación de este enfoque a la educación normal y a la especial presenta algunas diferencias. Se hace un desarrollo teórico de los principales componente del modelo (identificación de necesidades, definición de objetivos, análisis de tareas, evaluación, secuenciación), así como una descripción del procedimiento y las diversas técnicas relativas a cada uno de ellos (sistemas de incentivos, materiales, sistemas de registro, requisitos de los sujetos, etc.). 相似文献
9.
10.
The aim of this paper is to study the link relationships in the Nordic academic web space – comprised of 23 Finnish, 11 Danish and 28 Swedish academic web domains with the European one. Through social networks analysis we intend to detect sub-networks within the Nordic network, the position and role of the different university web domains and to understand the structural topology of this web space. Co-link analysis, with asymmetrical matrices and cosine measure, is used to identify thematic clusters. Results show that the Nordic network is a cohesive network, set up by three well-defined sub-networks and it rests on the Finnish and Swedish sub-networks. We conclude that the Danish network has less visibility than other Nordic countries. The Swedish one is the principal Nordic sub-network and the Finland network is a slightly isolated from Europe, with the exception of the University of Helsinki. 相似文献