Children from low-income families have a higher incidence for developing early onset cardio-metabolic disease risk factors. Optimal levels of health-related fitness may attenuate risk, but little research has examined...Children from low-income families have a higher incidence for developing early onset cardio-metabolic disease risk factors. Optimal levels of health-related fitness may attenuate risk, but little research has examined its relationships with individual cardio-metabolic blood markers in low-income children. The purpose of this study was to examine the prevalence and correlates of unfavorable cardio-metabolic blood profiles in children from low-income families. Data were collected and analyzed on 124 children (mean age = 10.4 ± 0.9 years;57 girls, 67 boys;97% Hispanic) recruited from three urban Title I schools from the state of Utah in the US Health-related fitness. Measures were collected using the validated FITNESSGRAM fitness test battery. The Cholestech LDX system was used to analyze students’ total cholesterol (TC), LDL cholesterol, HDL cholesterol, triglycerides (TRI), and blood glucose (BG). Capillary blood samples via finger sticks were collected while each student was in a fasted state before school hours. Unfavorable measurements were defined as TC ≥ 200 mg/dL, LDL ≥ 130 mg/dL, HDL 150 mg/dL, and BG ≥ 100 mg/dL (pre-diabetes). Approximately 5.3% of the total sample had unfavorable TC, 16.7% had unfavorable HDL, 16.0% had unfavorable LDL, 15.2% had unfavorable TRI, and 25.4% had unfavorable BG (pre-diabetes). Pearson’s chi-square tests revealed no significant differences between sexes on any unfavorable classification after alpha level adjustment (p > 0.01). When all parameters were analyzed as continuous variables, Spearman’s rank correlation revealed a statistically significant linear relationship between aerobic fitness and LDL in boys (rs = -?0.65, p - 0.46, p < 0.01), and between BMI and BG in girls (rs = 0.56, p < 0.01). Aerobic fitness relates to LDL cholesterol in low-income boys and BMI relates to HDL cholesterol and BG in low-income girls.展开更多
Purpose To examine the association between bullying victimization and meeting recommendations for the 24-h movement behaviors of physical activity,screen use,and sleep in adolescents.Methods Participants were a sample...Purpose To examine the association between bullying victimization and meeting recommendations for the 24-h movement behaviors of physical activity,screen use,and sleep in adolescents.Methods Participants were a sample of US adolescents from the 2015–2019 national Youth Risk Behavior Survey(N=43,847;Mean age=16.0±1.2 years;50.7%female).The bullying victimization variables included the bullying expe-riences at school and online.Weighted multivariable logistic regressions analyzed associations between bullying victimiza-tion and meeting recommendations for 24-h movement behaviors controlling for age,sex,race/ethnicity,and weight status.Results Adolescents meeting non-academic screen and sleep recommendations had 25%(OR=0.75,95%CI 0.69–0.82)and 19%(OR=0.81,95%CI 0.74–0.89)lower odds to be bullied at school.Adolescents meeting non-academic screen recommen-dation had 27%lower odds(OR=0.73,95%CI 0.58–0.91)of experience online bullying.Male adolescents who met physical activity,non-academic screen use,and sleep recommendations had lower odds of experience the bullying at school of 29%(OR=0.71,95%CI 0.59–0.85),26%(OR=0.74,95%CI 0.61–0.90),and 31%(OR=0.69,95%CI 0.55–0.86),respectively.Among the females,non-academic screen use was the only movement behavior yielded statistical significance,in that those who met the recommendation had 15%(OR=0.85,95%CI 0.73–0.98)lower odds of experience the bullying at school.Conclusion The presence of meeting 24-h movement behavior recommendations associates with a lower probability of bullying at school and online in adolescents.Interestingly,these associations tended to be stronger and more consistent in males compared to females.展开更多
The cavitation is very common in a centrifugal pump,especially when the speed is very high,and it seriously influences the centrifugal pump performance.In this investigation,the RNG k-ε turbulence model and the cavit...The cavitation is very common in a centrifugal pump,especially when the speed is very high,and it seriously influences the centrifugal pump performance.In this investigation,the RNG k-ε turbulence model and the cavitation model with consideration of the mass transferring are first used to simulate the cavitation performance of the high-speed centrifugal pump without taking any measure for improving the pump cavitation performance.The calculation results reveal that a number of bubbles appear in the centrifugal pump flow channel,and the head as well as the flow rate of the high-speed centrifugal pump are far from its design condition.The cavitation performance can be improved effectively by arranging a variable pitch inducer and adopting an annular nozzle scheme.The flow field analysis of the pump is conducted to obtain the suitable working temperature distribution at different void fractions.On one hand,with the same void fraction,the head of the centrifugal pump drops slowly with the increase of temperature.However,when the temperature exceeds 90°C,the head of the pump drops rapidly.On the other hand,at the constant temperature,the higher the void fraction,the worse the cavitation performance.This research conducted under different temperatures and void fractions provides some guidance for designing an effective high-speed centrifugal pump.展开更多
Purpose To compare physical activity and sedentary behavior between four commonly used subjective and objective meas-ures:the 7-day Physical Activity Recall (7DPAR),International Physical Activity Questionnaire (IPAQ)...Purpose To compare physical activity and sedentary behavior between four commonly used subjective and objective meas-ures:the 7-day Physical Activity Recall (7DPAR),International Physical Activity Questionnaire (IPAQ),pedometer,and accelerometer.Methods A total of 130 college students completed four measures for the same 7 days.Body composition was measured using a bioelectric impedance analyzer.Wilcoxon signed rank tests and Spearman correlations were performed to compare estimates between activity measures.The Spearman correlations between different activity measures were further examined separately for the higher and the lower body fat groups.Results Compared with accelerometer-derived data,both the 7DPAR and the IPAQ overestimated light physical activity(P < 0.001) while underestimated sedentary behavior (P < 0.001).Across comparisons,the highest correlation was found between accelerometers and pedometers on steps/day (r =0.72,P < 0.001).The 7DPAR and the IPAQ were correlated with each other for all physical activity variables and sedentary behavior (r =0.37-0.45).There were low correlations (r=0.20-0.47) between the 7DPAR,the IPAQ,and accelerometers in sedentary behavior,light physical activity,and vigorous physical activity.Higher correlations between different activity modalities were observed among individuals with lower body fat(r=0.41-0.80) than among those with higher body fat (r=0.31-0.65).Conclusions The 7DPAR and the IPAQ yielded comparable estimation of moderate physical activity relative to accelerom-eters.There were significant differences in sedentary time across activity measures.Body compositions should be considered when comparing the estimates of activity levels between subjective and objective instruments.展开更多
Background Physical activity programs using components of resistance have the potential to improve health in school chil-dren.The purpose of this study was to examine the effect of a school-based resistance exercise p...Background Physical activity programs using components of resistance have the potential to improve health in school chil-dren.The purpose of this study was to examine the effect of a school-based resistance exercise program on physical fitness in elementary school students.Methods The sample was 256 children(mean age=8.3±2.5 years;119 girls)from kindergarten to 5th grade.Participants performed a 10-min resistance exercise 2-3 times in each school day.Physical fitness outcomes were assessed using President’s Physical Fitness Challenge test.Measures were collected at baseline and at a 6-month post-test time point.A 2×2 doubly MANOVA was employed to examine the effect of sex and time.Results The multivariate model was statistically significant with a main time effect(Wilks’λ=0.19,F=290.9,P<0.001).Follow-univariate tests found significant differences between time-points on flex arm hang(P=0.033),shuttle run(P<0.001),and 1-mile run/walk times(P<0.001).Conclusions A 6-month resistance exercise program improved upper body strength and cardiorespiratory endurance in elementary school aged children.The use of resistance exercise intervention during school day can be effectively used to promote physical fitness and ultimately improve the health of children.展开更多
文摘Children from low-income families have a higher incidence for developing early onset cardio-metabolic disease risk factors. Optimal levels of health-related fitness may attenuate risk, but little research has examined its relationships with individual cardio-metabolic blood markers in low-income children. The purpose of this study was to examine the prevalence and correlates of unfavorable cardio-metabolic blood profiles in children from low-income families. Data were collected and analyzed on 124 children (mean age = 10.4 ± 0.9 years;57 girls, 67 boys;97% Hispanic) recruited from three urban Title I schools from the state of Utah in the US Health-related fitness. Measures were collected using the validated FITNESSGRAM fitness test battery. The Cholestech LDX system was used to analyze students’ total cholesterol (TC), LDL cholesterol, HDL cholesterol, triglycerides (TRI), and blood glucose (BG). Capillary blood samples via finger sticks were collected while each student was in a fasted state before school hours. Unfavorable measurements were defined as TC ≥ 200 mg/dL, LDL ≥ 130 mg/dL, HDL 150 mg/dL, and BG ≥ 100 mg/dL (pre-diabetes). Approximately 5.3% of the total sample had unfavorable TC, 16.7% had unfavorable HDL, 16.0% had unfavorable LDL, 15.2% had unfavorable TRI, and 25.4% had unfavorable BG (pre-diabetes). Pearson’s chi-square tests revealed no significant differences between sexes on any unfavorable classification after alpha level adjustment (p > 0.01). When all parameters were analyzed as continuous variables, Spearman’s rank correlation revealed a statistically significant linear relationship between aerobic fitness and LDL in boys (rs = -?0.65, p - 0.46, p < 0.01), and between BMI and BG in girls (rs = 0.56, p < 0.01). Aerobic fitness relates to LDL cholesterol in low-income boys and BMI relates to HDL cholesterol and BG in low-income girls.
文摘Purpose To examine the association between bullying victimization and meeting recommendations for the 24-h movement behaviors of physical activity,screen use,and sleep in adolescents.Methods Participants were a sample of US adolescents from the 2015–2019 national Youth Risk Behavior Survey(N=43,847;Mean age=16.0±1.2 years;50.7%female).The bullying victimization variables included the bullying expe-riences at school and online.Weighted multivariable logistic regressions analyzed associations between bullying victimiza-tion and meeting recommendations for 24-h movement behaviors controlling for age,sex,race/ethnicity,and weight status.Results Adolescents meeting non-academic screen and sleep recommendations had 25%(OR=0.75,95%CI 0.69–0.82)and 19%(OR=0.81,95%CI 0.74–0.89)lower odds to be bullied at school.Adolescents meeting non-academic screen recommen-dation had 27%lower odds(OR=0.73,95%CI 0.58–0.91)of experience online bullying.Male adolescents who met physical activity,non-academic screen use,and sleep recommendations had lower odds of experience the bullying at school of 29%(OR=0.71,95%CI 0.59–0.85),26%(OR=0.74,95%CI 0.61–0.90),and 31%(OR=0.69,95%CI 0.55–0.86),respectively.Among the females,non-academic screen use was the only movement behavior yielded statistical significance,in that those who met the recommendation had 15%(OR=0.85,95%CI 0.73–0.98)lower odds of experience the bullying at school.Conclusion The presence of meeting 24-h movement behavior recommendations associates with a lower probability of bullying at school and online in adolescents.Interestingly,these associations tended to be stronger and more consistent in males compared to females.
基金the National Natural Science Foundation of China (Grant No.51279145).
文摘The cavitation is very common in a centrifugal pump,especially when the speed is very high,and it seriously influences the centrifugal pump performance.In this investigation,the RNG k-ε turbulence model and the cavitation model with consideration of the mass transferring are first used to simulate the cavitation performance of the high-speed centrifugal pump without taking any measure for improving the pump cavitation performance.The calculation results reveal that a number of bubbles appear in the centrifugal pump flow channel,and the head as well as the flow rate of the high-speed centrifugal pump are far from its design condition.The cavitation performance can be improved effectively by arranging a variable pitch inducer and adopting an annular nozzle scheme.The flow field analysis of the pump is conducted to obtain the suitable working temperature distribution at different void fractions.On one hand,with the same void fraction,the head of the centrifugal pump drops slowly with the increase of temperature.However,when the temperature exceeds 90°C,the head of the pump drops rapidly.On the other hand,at the constant temperature,the higher the void fraction,the worse the cavitation performance.This research conducted under different temperatures and void fractions provides some guidance for designing an effective high-speed centrifugal pump.
基金supported by the MOST 102-2410-H-041-009,Taiwan,China。
文摘Purpose To compare physical activity and sedentary behavior between four commonly used subjective and objective meas-ures:the 7-day Physical Activity Recall (7DPAR),International Physical Activity Questionnaire (IPAQ),pedometer,and accelerometer.Methods A total of 130 college students completed four measures for the same 7 days.Body composition was measured using a bioelectric impedance analyzer.Wilcoxon signed rank tests and Spearman correlations were performed to compare estimates between activity measures.The Spearman correlations between different activity measures were further examined separately for the higher and the lower body fat groups.Results Compared with accelerometer-derived data,both the 7DPAR and the IPAQ overestimated light physical activity(P < 0.001) while underestimated sedentary behavior (P < 0.001).Across comparisons,the highest correlation was found between accelerometers and pedometers on steps/day (r =0.72,P < 0.001).The 7DPAR and the IPAQ were correlated with each other for all physical activity variables and sedentary behavior (r =0.37-0.45).There were low correlations (r=0.20-0.47) between the 7DPAR,the IPAQ,and accelerometers in sedentary behavior,light physical activity,and vigorous physical activity.Higher correlations between different activity modalities were observed among individuals with lower body fat(r=0.41-0.80) than among those with higher body fat (r=0.31-0.65).Conclusions The 7DPAR and the IPAQ yielded comparable estimation of moderate physical activity relative to accelerom-eters.There were significant differences in sedentary time across activity measures.Body compositions should be considered when comparing the estimates of activity levels between subjective and objective instruments.
文摘Background Physical activity programs using components of resistance have the potential to improve health in school chil-dren.The purpose of this study was to examine the effect of a school-based resistance exercise program on physical fitness in elementary school students.Methods The sample was 256 children(mean age=8.3±2.5 years;119 girls)from kindergarten to 5th grade.Participants performed a 10-min resistance exercise 2-3 times in each school day.Physical fitness outcomes were assessed using President’s Physical Fitness Challenge test.Measures were collected at baseline and at a 6-month post-test time point.A 2×2 doubly MANOVA was employed to examine the effect of sex and time.Results The multivariate model was statistically significant with a main time effect(Wilks’λ=0.19,F=290.9,P<0.001).Follow-univariate tests found significant differences between time-points on flex arm hang(P=0.033),shuttle run(P<0.001),and 1-mile run/walk times(P<0.001).Conclusions A 6-month resistance exercise program improved upper body strength and cardiorespiratory endurance in elementary school aged children.The use of resistance exercise intervention during school day can be effectively used to promote physical fitness and ultimately improve the health of children.
