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61.
Associations Between Sexting Behaviors and Sexual Behaviors Among Mobile Phone‐Owning Teens in Los Angeles 下载免费PDF全文
Eric Rice Jaih Craddock Mary Hemler Joshua Rusow Aaron Plant Jorge Montoya Timothy Kordic 《Child development》2018,89(1):110-117
The implications of teen sexting for healthy development continue to concern parents, academics, and the general public. Using a probability sample of high school students (N = 1,208) aged 12–18, the prevalence of sexting, associations with sexting, and associations between sexing and sexual activity were assessed. Seventeen percent both sent and received sexts, and 24% only received sexts. Sending and receiving sexts were positively associated with each other and both behaviors were associated with having peers who sext. Lifetime reports of sexual intercourse, anal sex, oral sex, and recent unprotected sex were positively associated with reports of texting 300 or more times per day, only receiving sexts, and both sending and receiving sexts. 相似文献
62.
Associations Among Infant Iron Deficiency,Childhood Emotion and Attention Regulation,and Adolescent Problem Behaviors 下载免费PDF全文
Patricia East Erin Delker Betsy Lozoff Jorge Delva Marcela Castillo Sheila Gahagan 《Child development》2018,89(2):593-608
This study examined whether iron deficiency (ID) in infancy contributes to problem behaviors in adolescence through its influence on poor regulatory abilities in childhood. Chilean infants (N = 1,116) were studied when there was no national program for iron fortification (1991–1996), resulting in high rates of ID (28%) and iron‐deficiency anemia (IDA, 17%). Infants (54% male) were studied at childhood (Mage = 10 years) and adolescence (Mage = 14 years). IDA in infancy was related to excessive alcohol use and risky sexual behavior in adolescence through its effect on poor emotion regulation in childhood. Attentional control deficits at age 10 were also related to both infant IDA and heightened risk taking in adolescence. Findings elucidate how poor childhood regulatory abilities associated with infant IDA compromise adjustment in adolescence. 相似文献
63.
Jorge Knijnik 《Sport in Society》2018,21(6):946-959
AbstractThis article addresses key questions of social agency and cultural pedagogy within the neoliberal structures of ‘modern football’ in the Australian context. It reports on a two-year ethnographic study of the Red and Black Bloc, an Australian ultras group in Western Sydney, one of the most culturally diverse areas in Australia. The origins of the Western Sydney ultras are described, along with their struggles to build their own cultural identity and to fight for social agency within a commodified football league. By combining a multifaceted theoretical model with a range of ethnographic data – including document analysis and in-depth interviews – this study reveals the processes by which the Western Sydney ultras enhance members’ social cohesion towards an increased social consciousness. The paper acknowledges the role that ultras, as authentic cultural formations, may have in the propagation of new cultural pedagogies that have the potential to enhance citizenship, communal life and participatory democracy. 相似文献
64.
Aurelio Cabello-Garrido Enrique España-Ramos Ángel Blanco-López 《International Journal of Science and Mathematics Education》2018,16(7):1269-1289
This paper describes the application of the methodology developed in research on learning progressions to a health-related topic. More specifically, we present a human nutrition learning progression as a hypothesis that now requires empirical validation. The study involved three phases. In the first phase, we analysed the existing literature in the domain of human nutrition. Based on this analysis, phase 2 then involved drawing up a learning progression for this domain and identifying the learning targets and progress variables, as well as the upper and lower anchors. The analysis led us to identify five progress variables, associated with the development of the concepts of food, nutrient, energy and diet, as well as with the ability to classify foods according to their nutrients. Finally, in phase 3, we identified and described the pathways that students may follow in relation to each progress variable. Given its focus on a topic closely linked to personal health, the learning progression may be useful not only as a component of teaching modules that aim to improve scientific literacy but also as a platform for future health education campaigns that seek to promote healthy eating habits among different sectors of the population. 相似文献
65.
Jorge Pérez-Gómez JoséCarmelo Adsuar Pedro EAlcaraz Jorge Carlos-Vivas 《运动与健康科学(英文)》2022,11(1):115-122
Background:Football is the most practised sport in the world and is associated with the risk of injuries in the players.Some studies have been published that identify injury prevention programs,but there is no review of the full body of evidence on injury prevention programs for use by football coaches.The aim of this article was to carry out a systematic review of published studies on injury prevention programs for adult male footballers,identify points of common understanding and establish recommendations that should be considered in the design of injury prevention strategies.Methods:PubMed and EMBASE databases were used to identify relevant published articles using the following keywords:"soccer"AND"injury"AND"prevention".Results:A total of 2512 studies were identified initially,but only 11 studies met the inclusion criteria,and their outcomes are presented.Results revealed that injury prevention programs in football have focused on strength training,proprioceptive training,multicomponent programs(balance,core stability,and functional strength and mobility),and warm-up programs.Conclusion:Based on results from the studies analyzed,football players can lower the incidence of match and training injuries by participating in dynamic warm-up programs that include preventive exercises before games or during training sessions,and by adding strength,balance,and mobility training to the training sessions. 相似文献
66.
Manuel TORAL IBAEZ Margarita CARU Miguel A.HERRERA Luis GONZALEZ Luis M.MARTIN Jorge MIRANDA Rafael M.NAVARRO-CERRILLO 《Journal of Zhejiang University. Science. B》2009,10(2)
A protocol of polymerase chain reaction-random amplified polymorphic DNAs (PCR-RAPDs) was established to analyse the gene diversity and genotype identification for clones of Sequoia sempervirens (D.Don) Endl.in Chile.Ten (out of 34) clones from introduction trial located in Voipir-Viilarrica,Chile,were studied.The PCR-RAPDs technique and a modified hexadecyltrimethylammonium bromide (CTAB) protocol were used for genomic DNA extraction.The PCR tests were carried out employing 10-mer random primers.The amplification products were detected by electrophoresis in agarose gels.Forty nine polymorphic bands were obtained with the selected primers (BG04,BF07,BF 12,BF13,and BF 14) and were ordered according to their molecular size.The genetic similarity between samples was calculated by the Jaccard index and a dendrogram was constructed using a cluster analysis of unweighted pair group method using arithmetic averages (UPGMA).Of the primers tested,5 (out of 60) RAPD primers were selected for their reproducibility and high polymorphism.A total of 49 polymorphic RAPD bands were detected out of 252 bands.The genetic similarity analysis demonstrates an extensive genetic variability between the tested clones and the dendrogram depicts the genetic relationships among the clones,suggesting a geographic relationship.The results indicate that the RAPD markers permitted the identification of the assayed clones,although they are derived from the same geographic origin. 相似文献
67.
Manuel Toral Ibañez Margarita Caru Miguel A. Herrera Luis Gonzalez Luis M. Martin Jorge Miranda Rafael M. Navarro-Cerrillo 《Journal of Zhejiang University. Science. B》2009,10(2):112-119
A protocol of polymerase chain reaction-random amplified polymorphic DNAs (PCR-RAPDs) was established to analyse the gene
diversity and genotype identification for clones of Sequoia sempervirens (D. Don) Endl. in Chile. Ten (out of 34) clones from introduction trial located in Voipir-Villarrica, Chile, were studied.
The PCR-RAPDs technique and a modified hexadecyltrimethylammonium bromide (CTAB) protocol were used for genomic DNA extraction.
The PCR tests were carried out employing 10-mer random primers. The amplification products were detected by electrophoresis
in agarose gels. Forty nine polymorphic bands were obtained with the selected primers (BG04, BF07, BF12, BF13, and BF14) and
were ordered according to their molecular size. The genetic similarity between samples was calculated by the Jaccard index
and a dendrogram was constructed using a cluster analysis of unweighted pair group method using arithmetic averages (UPGMA).
Of the primers tested, 5 (out of 60) RAPD primers were selected for their reproducibility and high polymorphism. A total of
49 polymorphic RAPD bands were detected out of 252 bands. The genetic similarity analysis demonstrates an extensive genetic
variability between the tested clones and the dendrogram depicts the genetic relationships among the clones, suggesting a
geographic relationship. The results indicate that the RAPD markers permitted the identification of the assayed clones, although
they are derived from the same geographic origin.
Project (No. CONICYT-FONDEF PROYECT D01 I 1008) supported by the National Commission of Science and Research of Chile 相似文献
68.
Jorge Arede Pedro Esteves António Paulo Ferreira Jaime Sampaio Nuno Leite 《Journal of sports sciences》2013,31(19):2220-2227
ABSTRACTThe aims of this study were to examine the medium-term effects of previous experiences during early stages of sport development on physical capacities of under-13 (U-13) talented basketball players and, to identify variables that discriminated under-14 (U-14) national team training camp selection. Anthropometrical and physical measurements were collected during a basketball training camp. Previous sport experiences (6–10 years), maturity offset, power outputs for jumping and sprinting were determined. A cluster analysis was used to allocate the subjects according to their different levels of sport experiences (more specialized vs. less specialized) to allow creating a dummy variable for the subsequent analysis of the physical variables. A stepwise discriminant analysis was computed to identify the construct that best classifies selected and non-selected players for U-14 national team training camp. The less specialized group outscored more specialized in all physical parameters, irrespectively of gender. The Abalakov Jump Peak Power and Predicted Adult Height (PAH) could successfully discriminate selected from non-selected players for U-14 national team training camp in boys and PAHin girls. The diversified and non-specific sport stimulus during early ages seem to be determinant to the acquisition and development of fundamental movement skills of talented basketball players. 相似文献
69.
Marcos Gutiérrez-Dávila Matteo Caletti Raquel Antonio Enrique Navarro 《Journal of sports sciences》2013,31(10):1100-1107
Abstract The aim of this study was to test the effect that changing targets during a simple long lunge attack in fencing exerts on the temporal parameters of the reaction response, the execution speed, and the precision and the coordination of the movement pattern. Thirty fencers with more than 10 years of experience participated in this study. Two force platforms were used to record the horizontal components of the reaction forces and thereby to determine the beginning of the movement. A three-dimensional (3D) system recorded the spatial positions of the 9 markers situated on the fencer plus the epee, while a moving target was projected on a screen, enabling the control of the target change. The results indicated that when a target change is provoked the reaction time (RT), movement time (MT), and the time used in the acceleration phase of the centre of mass (CM) increases significantly with respect to the attack executed with a straight thrust. The speed and horizontal distance reached by the CM at the end of the acceleration phase (VX(CM) and SX(CM), respectively) significantly decreased, while the errors increased. However, the temporal sequence of the movement pattern did not appreciably change. 相似文献
70.
Pedro Silva Jorge Mota Dale Esliger Gregory Welk 《Measurement in physical education and exercise science》2013,17(2):79-91
The purpose of this study was to determine the reliability of the Actigraph GT1M (Pensacola, FL, USA) accelerometer activity count and step functions. Fifty GT1M accelerometers were initialized to collect simultaneous acceleration counts and steps data using 15-sec epochs. All reliability testing was completed using a mechanical shaker plate to perform six different test conditions in Experiment 1 and 18 test conditions in Experiment 2. The overall intra- and inter-instrument reliability of the GT1M was CVintra = 2.9% and CVinter = 3.5% for counts and CVintra = 1.1% and CVinter = 1.2% for steps. No batch effects were evident in the 50 GT1Ms. The Actigraph GT1M accelerometer demonstrated good reliability for measuring both counts and steps. However, the ability of the GT1M to consistently detect acceleration at a given acceleration and frequency condition varied widely. Future studies clarifying the filtering limitations and the threshold necessary to detect the occurrence of movement are warranted. 相似文献