The mechanical properties of red sandstone subjected to cyclic point loading were investigated. Tests were conducted using MTS servohydraulic landmark test system, under cyclic loadings with constant amplitudes and in...The mechanical properties of red sandstone subjected to cyclic point loading were investigated. Tests were conducted using MTS servohydraulic landmark test system, under cyclic loadings with constant amplitudes and increasing multi-level amplitudes. The frequencies range from 0.1 to 5 Hz and lower limit load ratios range from 0 to 0.60. Laboratory investigations were performed to find the effect of the frequency and the lower limit load ratio on the fatigue life and hysteresis properties of sandstone. The results show that the fatigue life of sandstone decreases first and then increases with the increase of frequency and lower limit load ratio. Under the same cycle number, the spacing between hysteresis loops increases with rising frequency and decreasing lower limit load ratio. The existence of “training” and “memory” effects in red sandstone under cyclic point loading was proved.展开更多
As the focus on academic achievement has increased,physical activity(PA) opportunities in schools have decreased in the United States.In an attempt to discover how the decline in PA may affect academic achievement,res...As the focus on academic achievement has increased,physical activity(PA) opportunities in schools have decreased in the United States.In an attempt to discover how the decline in PA may affect academic achievement,researchers have been studying the effects of PA on cognition and academic achievement in children for more than 50 years.This review takes a historical perspective on the science of PA and academic achievement prior to and during the past 5 years.A total of 125 published articles were included and reviewed.Fifty-three of these articles were published in the past 5 years.In recent years,the overall quality of the studies has increased,but the results continue to be inconsistent.Many use cross-sectional designs and the methods vary substantially.The majority of conclusions show a positive effect of PA on constructs related to academic achievement.Future studies should use strong study designs to examine the types and doses of PA needed to produce improvements in academic achievement.展开更多
Exchange bias effect is observed in the phase separated La0.33Pr0.34Ca0.33MnO3 thin films. High exchange bias field of about 1 kOe is achieved at 4 K. The exchange bias effect in La0.33Pr0.34Ca0.33MnO3 thin films migh...Exchange bias effect is observed in the phase separated La0.33Pr0.34Ca0.33MnO3 thin films. High exchange bias field of about 1 kOe is achieved at 4 K. The exchange bias effect in La0.33Pr0.34Ca0.33MnO3 thin films might originate from the intrinsic phase separation of the La0.33Pr0.34Ca0.33MnO3 or surface effect. The dependence of exchange bias effect on temperature, cooling field, and thickness is also investigated. This work would open an avenue to the application in the magnetic memory devices based on the phase separated manganites.展开更多
Physical literacy （PL）, as embodied within physical education （PE）, has been vaunted as having increasing importance as a disposition for students of all abilities to establish lifelong adherence to physical activ...Physical literacy （PL）, as embodied within physical education （PE）, has been vaunted as having increasing importance as a disposition for students of all abilities to establish lifelong adherence to physical activity. The purpose of this paper was to provide a discussion of how the pedagogical features of a contemporary pedagogical model, Sport Education （SE）, may be used to operationalize PL in PE and what empirical evidence currently exists to validate this claim. Substantial empirical evidence exists that the attributes associated with the development of PL （Whitehead, 2010） can be operationalized in PE with the effective implementation of the model. SE has distinct pedagogical features which positively contribute to many of the dimensions of PL and can further an individuals＇ journey towards greater PL and having an embodied self within PE. That stated, there remains concern that the context for this embodiment remains too narrow to be viewed as a panacea for the development of lifelong physical activity. SE must be developed as a connective specialism if these PL attributes are to transform the motivation and confidence for individuals to capitalize on their innate physical potential and make a more significant contribution to the quality of life.展开更多
AIM:To assess nutrition,physical activity and health-ful knowledge in obese children with biopsy-proven nonalcoholic steatohepatitis(NASH or NA)compared to children without liver disease.METHODS:Children with biopsy-p...AIM:To assess nutrition,physical activity and health-ful knowledge in obese children with biopsy-proven nonalcoholic steatohepatitis(NASH or NA)compared to children without liver disease.METHODS:Children with biopsy-proven NASH comprised the NASH group.Age,sex and ethnicity matched control groups consisted of obese(OB)and lean(CO) children with no liver disease.Subjects were adminis-tered the School Physical Activity and Nutrition Survey and one blood draw was obtained.RESULTS:Fifty-seven patients were enrolled with a mean age of 12.1±2.1 years,and all were Hispanic.Even though the OB and NA had a similar increased body mass index(%),35%of the NA group always read nutrition labels compared to none in the OB(P<0.05),and more NA children felt their diet is"less healthy".NA consumed the least amount of fruits with only 25%having≥1 fruit/d vs 45%in OB and 64.7% in CO(P<0.05 NA vs CO).Only 15%of NA subjects performed light exercise vs 35%and 59%of OB and CO groups,respectively(P=0.02).The mean physical activity score was lowest in the NA group(P<0.05).Amongst the subjects with NASH,we found that 100% of patients with grade 2 or 3 fibrosis had a sedentary score>2 compared to only 63.6%of those with grade 1 or no fibrosis(P<0.05).CONCLUSION:Children with NASH had increased sedentary behavior,decreased activity,and fruit intake.Larger studies may determine the benefit of changing these behaviors as treatment for NASH.展开更多
基金Projects(51322403,51274254)supported by the National Natural Science Foundation of ChinaProject(2015CB060200)supported by the National Basic Research Program of China
文摘The mechanical properties of red sandstone subjected to cyclic point loading were investigated. Tests were conducted using MTS servohydraulic landmark test system, under cyclic loadings with constant amplitudes and increasing multi-level amplitudes. The frequencies range from 0.1 to 5 Hz and lower limit load ratios range from 0 to 0.60. Laboratory investigations were performed to find the effect of the frequency and the lower limit load ratio on the fatigue life and hysteresis properties of sandstone. The results show that the fatigue life of sandstone decreases first and then increases with the increase of frequency and lower limit load ratio. Under the same cycle number, the spacing between hysteresis loops increases with rising frequency and decreasing lower limit load ratio. The existence of “training” and “memory” effects in red sandstone under cyclic point loading was proved.
文摘As the focus on academic achievement has increased,physical activity(PA) opportunities in schools have decreased in the United States.In an attempt to discover how the decline in PA may affect academic achievement,researchers have been studying the effects of PA on cognition and academic achievement in children for more than 50 years.This review takes a historical perspective on the science of PA and academic achievement prior to and during the past 5 years.A total of 125 published articles were included and reviewed.Fifty-three of these articles were published in the past 5 years.In recent years,the overall quality of the studies has increased,but the results continue to be inconsistent.Many use cross-sectional designs and the methods vary substantially.The majority of conclusions show a positive effect of PA on constructs related to academic achievement.Future studies should use strong study designs to examine the types and doses of PA needed to produce improvements in academic achievement.
基金V. ACKNOWLEDGEMENTS This work was supported by the National Natural Science Foundation of China （No.11374279 and No.11034006）, the National Basic Research Program of China （No.2014CB921102）, the Strategic Priority Research Program of the Chinese Academy of Sciences （No.XDB01020000）, the Specialized Research Fund for the Doctoral Program of Higher Education （No.20113402110046）, and the Fundamental Research Funds for the Central Universities （No.WK2340000035）.
文摘Exchange bias effect is observed in the phase separated La0.33Pr0.34Ca0.33MnO3 thin films. High exchange bias field of about 1 kOe is achieved at 4 K. The exchange bias effect in La0.33Pr0.34Ca0.33MnO3 thin films might originate from the intrinsic phase separation of the La0.33Pr0.34Ca0.33MnO3 or surface effect. The dependence of exchange bias effect on temperature, cooling field, and thickness is also investigated. This work would open an avenue to the application in the magnetic memory devices based on the phase separated manganites.
文摘Physical literacy （PL）, as embodied within physical education （PE）, has been vaunted as having increasing importance as a disposition for students of all abilities to establish lifelong adherence to physical activity. The purpose of this paper was to provide a discussion of how the pedagogical features of a contemporary pedagogical model, Sport Education （SE）, may be used to operationalize PL in PE and what empirical evidence currently exists to validate this claim. Substantial empirical evidence exists that the attributes associated with the development of PL （Whitehead, 2010） can be operationalized in PE with the effective implementation of the model. SE has distinct pedagogical features which positively contribute to many of the dimensions of PL and can further an individuals＇ journey towards greater PL and having an embodied self within PE. That stated, there remains concern that the context for this embodiment remains too narrow to be viewed as a panacea for the development of lifelong physical activity. SE must be developed as a connective specialism if these PL attributes are to transform the motivation and confidence for individuals to capitalize on their innate physical potential and make a more significant contribution to the quality of life.
基金Supported by National Institute of Health[NIH K12 RR 17665(Morey Haymond,MD(PI)C Wayne Smith,MD(Mentor)]
文摘AIM:To assess nutrition,physical activity and health-ful knowledge in obese children with biopsy-proven nonalcoholic steatohepatitis(NASH or NA)compared to children without liver disease.METHODS:Children with biopsy-proven NASH comprised the NASH group.Age,sex and ethnicity matched control groups consisted of obese(OB)and lean(CO) children with no liver disease.Subjects were adminis-tered the School Physical Activity and Nutrition Survey and one blood draw was obtained.RESULTS:Fifty-seven patients were enrolled with a mean age of 12.1±2.1 years,and all were Hispanic.Even though the OB and NA had a similar increased body mass index(%),35%of the NA group always read nutrition labels compared to none in the OB(P<0.05),and more NA children felt their diet is"less healthy".NA consumed the least amount of fruits with only 25%having≥1 fruit/d vs 45%in OB and 64.7% in CO(P<0.05 NA vs CO).Only 15%of NA subjects performed light exercise vs 35%and 59%of OB and CO groups,respectively(P=0.02).The mean physical activity score was lowest in the NA group(P<0.05).Amongst the subjects with NASH,we found that 100% of patients with grade 2 or 3 fibrosis had a sedentary score>2 compared to only 63.6%of those with grade 1 or no fibrosis(P<0.05).CONCLUSION:Children with NASH had increased sedentary behavior,decreased activity,and fruit intake.Larger studies may determine the benefit of changing these behaviors as treatment for NASH.
