Study on the Influence of New Media on College Students’ Physical Exercise Behavior

New media is becoming an important method to promote physical exercise,and it is also an essential factor affecting the physical exercise behavior of college students.This study takes the influence of new media sports information on college students’physical exercise behavior as the research objective.By using a questionnaire survey and mathematical statistics,545 college students in Shandong Province of China are selected as research samples.Based on the theory of new media exposure,fitness behavior theory,and self-efficacy theory,this study systematically discusses the influence and mechanism of new media exposure on the physical exercise behavior of college students in Shandong Province,so as to help college students improve their physical exercise behavior.

Cultural Adaptation and Psychometric Evaluation of Physical Activity Social Cognitive Scales for Brazilian Adolescents

SCT （social cognitive theory） provides a useful framework to explain why people acquire and maintain PA （physical activity） behaviors among adolescents. This study aimed to adapt modernized Australian social cognitive scales of PA to the Portuguese language and evaluate their factorial and convergent validity and reliability. The adapted scales were tested in an adolescent sample from low-income communities in the city of Sao Paulo, Brazil （n = 173; 56.1% male）. Confirmatory factor analysis was employed to examine model-fit for each scale. The scales were assessed against self-report measures of moderate-to-vigorous physical activity for convergent validity. Reliability properties （ICC （lntra class confidence） and Cronbach＇s Alpha） were also determined. Each social cognitive scale represented a statistically sound measure： fit indices indicated each model to be adequate-to-exact fit to the data; significant correlations between most scales and either light, moderate or vigorous intensity PA behavior demonstrated good convergent validity; internal consistency was acceptable-to-good （α = 0.51-0.80）; rank order repeatability was acceptable-to-strong （ICC = 0.62-0.92）. Adapted social cognitive scales for physical activity for use among adolescents in the Brazilian context showed acceptable reliability and validity properties and may be useful to identify potential social cognitive correlates of PA, mediators of PA behavior change and the testing of theoretical models of SCT.

Reviving Direct Observation Methods for Physical Activity Behavior

Purpose:Current Direct Observation(DO)methods are burdensome to the observer and relevant limitations can be identified on the outcome information.This study aims to characterize DO from the observers’point of view and to analyze the feasibility and usefulness of visual information in the form of video.Method:data collection was done with ten adult males,observed while performing different physical activities in an indoor court.Sessions were video recorded by two cameras.Three observers performed systematic observation,using SOPLAY,with different sampling rates.Inter observer’s agreement and with reference data was analyzed by Cohen’s Kappa statistic.Results:SOPLAY highest agreement between observers was 0.611 on vigorous category and walking category had the lowest 0.188.It doubles the time needed to annotate the video with pauses,but half of player’s behavior is preserved.Conclusion(s):using video to support DO permits to collect more accurate data and a more detailed behavior categorization is warranted.Developments in computer vision are expected to reduce the human efforts in DO methods.

Optimization of submerged entry nozzle parameters for ultra-high casting speed continuous casting mold of billet

Controlling the flow behavior in the mold in an appropriate way is the basis for realizing the billet ultra-high speed continuous casting.Based on the new proposed physical water modeling experiment considering the effects of solidified shell and hydrostatic pressure,the flow behavior in the mold with cross section of 160 mm 9160 mm during continuous casting of billet is regulated by optimizing the inner diameters and immersion depths of submerged entry nozzle at the ultra-high casting speeds of 5.0–6.5 m/min.The results show that under the premise of no slag entrainment,as well as uniform coverage and keeping good fluidity of liquid slag layer on the top free surface of the fluid in the mold,the appropriate parameters of submerged entry nozzle under the ultra-high casting speed of billet are 50 mm in inner diameter,95 mm in outer diameter and 180 mm in immersion depth.And on the basis of the obtained parameters of submerged entry nozzle,it can be known that the reasonable ranges of level fluctuation and impacting depth of the stream in the mold are about 0.82-1.11 and 593-617 mm,respectively.