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Jennifer R. Warren Michael L. Hecht David A. Wagstaff Elvira Elek Khadidiatou Ndiaye Patricia Dustman Flavio F. Marsiglia 《Journal of Applied Communication Research》2006,34(2):209-227
This study sought to determine if exposure to two communication-oriented activities, videotapes and public service announcements, accounts for changes in substance use among adolescents participating in the Drug Resistance Strategies Project's keepin' it REAL adolescent substance use prevention curriculum. Middle-school students (4,734, 72% Latino) responded to questionnaires related to these analyses. An analysis of covariance (ANCOVA) model was fit separately to six substance use outcomes. The results suggested that intervention students who saw four or five videos engaged in less substance use in the past month than did students who saw fewer videos. Having seen the PSAs one or more times did not predict the reported change in substance use. 相似文献
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Donatella Persico Marcello Passarelli Francesca Pozzi Jeffrey Earp Francesca Maria Dagnino Flavio Manganello 《British journal of educational technology : journal of the Council for Educational Technology》2019,50(4):1687-1712
This paper explores the relationship between digital games and learning along the continuum from formal to informal learning. Games are an increasingly important component of our learning ecologies but their potential can prove difficult to fully harness due to the downsides of gaming in informal contexts and to the limitations games can present when adopted in formal learning contexts. The aim of this paper is to shed light on the strengths and weaknesses of games for learning, and to gather stakeholder recommendations for the main actors in the field. The adopted research approach is qualitative and participatory, involving players, teachers, parents, researchers and developers. Data from 25 interviews and 11 focus groups yielded insights into the educational, psychological and ethical aspects of play. Results suggest that gameplay influences individuals in a very personal manner, and that its effects cover a wide range of skills, extending to identity development. Hence, to harness this potential, all actors in the ecology need strong awareness of both the affordances and the risks of games, and deep respect for individuals’ LEs. The study has implications for a wide range of actors, including educators, players, researchers, parents, game developers and policymakers. 相似文献
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Andrea A. diSessa Flavio S. Azevedo Orit Parnafes 《Interactive Learning Environments》2013,21(1-2):109-159
This paper provides a review of the rhetoric behind the component movement in educational software, and a critical analysis and synthesis of issues underlying the movement. We draw on case studies of several significant recent component projects in order to assess claims and to uncover and examine issues that are less often considered. While our empirical base cannot definitively answer all the questions raised, we hope to bring some clarity and some empirically based judgments to bear on how a promising technological innovation can best serve educational ends. Our study led to a focus on three critical issues: (1) the nature of the environment in which components are configured and used; (2) the extent of modifiability that is necessary for effective re-use of components; (3) how the work of designing components and component configurations is distributed among people with different competencies. 相似文献
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Lead is commonly used for making small size organ-pipes instead of using tin alloys. In fact, when the organ-pipes are small enough to avoid collapsing due to room temperature creep, lead can be used instead of other alloys with superior mechanical properties, because it is relatively cheap, it is easy to form into different shapes, the tonality of the obtained sounds are acceptable and the corrosion resistance is quite good. However, organic substances such as organic acids released from the wood made support of the organ-pipes and organic contaminations of the air pumped through the pipes may lead to a rapid degradation of lead. In this study, the effect of organic acids, such as acetic acid, on the degradation of lead-made organ-pipes was investigated. Lead made specimens obtained from real organ-pipes were exposed to organic-acid rich environments and the induced degradation was monitored by means of electrochemical techniques. In literature, it was evidenced that the degradation promoted by the organic acids leads to the formation of lead oxides and carbonates characterized by a very high volume, which promotes a quick degradation of the lead specimens. The effect of different concentrations of acetic acid on the degradation rate of the organ pipes was investigated by means of electrochemical impedance spectroscopy (EIS). The effect of the acid concentration on the corrosion process occurring on lead surface was evaluated by means of cathodic and anodic polarization measurements in both aerated and degassed conditions. The morphology of the degradation products was investigated by means of SEM during exposure time in the aggressive environment. 相似文献
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Felipe Minozzo Carlos Leonardo Figueiredo Machado Eurico Nestor Wilhelm Rafael Grazioli Ronei Silveira Pinto 《European Journal of Sport Science》2018,18(10):1398-1404
Isokinetic hamstring-to-quadriceps (H:Q) ratios are frequently used to assess knee muscle strength imbalances and risk of injuries/re-injuries. The use of peak torque (PT) or total work (TW) to estimate joint stability may lead to different results because of the differences between these two neuromuscular variables. Thus, the current study aimed to compare the conventional and functional H:Q ratios calculated by PT and TW. Ninety-three male professional soccer players from Brazilian first division teams performed isokinetic concentric and eccentric contractions of the quadriceps and the hamstrings at 60°/s. Muscle strength balance was calculated using the conventional torque ratio (CTR) and conventional work ratio (CWR), functional torque ratio (FTR) and functional work ratio (FWR) were highly and moderately correlated between them (r?=?0.83 and r?=?0.73, respectively). The Wilcoxon statistical test revealed significant differences between CTR and CWR, as well as FTR and FWR (p?T-test demonstrated significant differences in mean CTR–CWR and FTR–FWR, whereas Bland–Altman plots showed non-consistent bias. In addition, the chi-square test demonstrated significant differences between players below the conventional reference values and functional reference values (p?相似文献
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A Small‐Scale Randomized Efficacy Trial of the Identity Project: Promoting Adolescents’ Ethnic–Racial Identity Exploration and Resolution 
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下载免费PDF全文 Adriana J. Umaña‐Taylor Sara Douglass Kimberly A. Updegraff Flavio F. Marsiglia 《Child development》2018,89(3):862-870
Adolescents’ ethnic–racial identity (ERI) formation represents an important developmental process that is associated with adjustment. The Identity Project intervention, grounded in developmental theory, was designed to engage adolescents in the ERI processes of exploration and resolution. The current small‐scale efficacy trial involved an ethnic–racially diverse sample of adolescents (N = 215; Mage = 15.02, SD = .68) from eight classrooms that were randomly assigned by classroom to the intervention or attention control group. Differences between conditions in ERI exploration at Time 2 were consistent with desired intervention effects; furthermore, higher levels of ERI exploration at Time 2 predicted increases in ERI resolution at Time 3 only for youth in the treatment condition. Findings provide preliminary evidence of program efficacy. 相似文献
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OBJECTIVE: The study examines the self-reported prevalence of childhood physical and sexual abuse in a large sample of Portuguese parents. METHOD: Nearly 1,000 parents (506 mothers and 426 fathers) were selected through public primary schools from the Northern area of Portugal. All completed the Portuguese version of the Childhood History Questionnaire (CHQ) [Journal of Family Violence 5 (1990) 15]. RESULTS: Results show that the prevalence of abuse was 73%, but more severe physical abuse involving sequelae/injury was reported by 9.5%. Most physical abuses began prior to age 13, with half continuing after age 13. No gender differences were found for rates of physical abuse. However, among the milder physical abuse without sequelae/injury, those women who experienced "whipping" or "slapping/kicking" were more likely to do so from their mothers than fathers. Among men who were "slapped/kicked" this was more likely to be from their fathers. Low rates of sexual abuse were found at 2.6% with no gender or age differences. Lack of a supportive adult in childhood related to the more severe abuses, but only in adolescence. Portuguese rates of abuse were consistently lower than those reported in USA and Spanish studies using the CHQ. CONCLUSIONS: This is the first retrospective, self-report study of childhood abuse in a large sample of Portuguese parents and, even with a participation rate of 69%, shows lower rates than in US and Spanish samples. 相似文献
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Lara Elena Gomes Vera Diogo Flávio Antônio de Souza Castro João Paulo Vilas-Boas Ricardo J. Fernandes Pedro Figueiredo 《Sports biomechanics / International Society of Biomechanics in Sports》2019,18(4):354-365
Synchronised swimming involves a variety of sculling movements essential for body support and propulsion but its study is scarce. We aimed to biomechanically compare standard and contra-standard sculling techniques, and to observe the relationship between measures. Six synchronised swimmers performed two, 30 s maximal intensity, fully tethered standard and contra-standard sculling motions. Kinetic and kinematic data were obtained using a load-cell and underwater cameras, respectively. Force decreased along both techniques’ bouts, but no differences in-between techniques were noted for any kinetic variables. Standard sculling presented a higher cycle rate and a lower elbow mean angle than the contra-standard sculling (2.4 ± 0.3 vs. 2.0 ± 0.2 cycles/s and 134.1 ± 5.8 and 141.5 ± 4.7°, p < 0.05). In the standard sculling, by removing and maintaining the variation between participants (r w and r, respectively), the absolute mean force was directly related with cycle rate (r w = 0.60) and wrist angular velocity during flexion (r = 0.82), while in the contra-standard condition the force was inversely associated with wrist mean angle (r = ?0.95) and directly with hand speed (r w = 0.76), and elbow angular velocity (r w ≈ 0.60). Therefore, technique learning and training require different attention by coaches and swimmers. 相似文献