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51.
Daniel D. Bingham Silvia Costa Stacy A. Clemes Ash C. Routen Helen J. Moore Sally E. Barber 《Journal of sports sciences》2016,34(20):2005-2010
This study presents a worked example of a stepped process to reliably estimate the habitual physical activity and sedentary time of a sample of young children. A total of 299 children (2.9 ± 0.6 years) were recruited. Outcome variables were daily minutes of total physical activity, sedentary time, moderate to vigorous physical activity and proportional values of each variable. In total, 282 (94%) provided 3 h of accelerometer data on ≥1 day and were included in a 6-step process: Step-1: determine minimum wear-time; Step-2: process 7-day-data; Step-3: determine the inclusion of a weekend day; Step-4: examine day-to-day variability; Step-5: calculate single day intraclass correlation (ICC) (2,1); Step-6: calculate number of days required to reach reliability. Following the process the results were, Step-1: 6 h was estimated as minimum wear-time of a standard day. Step-2: 98 (32%) children had ≥6 h wear on 7 days. Step-3: no differences were found between weekdays and weekend days (P ≥ 0.05). Step-4: no differences were found between day-to-day variability (P ≥ 0.05). Step-5: single day ICC’s (2,1) ranged from 0.48 (total physical activity and sedentary time) to 0.53 (proportion of moderate to vigorous physical activity). Step-6: to reach reliability (ICC = 0.7), 3 days were required for all outcomes. In conclusion following a 7 day wear protocol, ≥6 h on any 3 days was found to have acceptable reliability. The stepped-process offers researchers a method to derive sample-specific wear-time criterion. 相似文献
52.
9.11事件后地缘政治观的反思 总被引:1,自引:0,他引:1
赵为民 《洛阳师范学院学报》2002,21(6):26-28
地缘政治这一传统观念在经济全球化、政治趋向多极化的背景下,遇到了强有力的挑战。9.11事件后美国政府正在重构其地缘逻辑思维。适时提出“时缘政治”和“人缘政治”概念,全面审视世界政治格局。我国应从国家利益出发,积极重构地缘战略格局。 相似文献
53.
龚萍 《荆州师范学院学报》2005,28(4):104-106
英汉语在“时间是空间”、“时间流逝是运动”、“时间是金钱”、“时间是实体”等主要时间概念隐喻及相应的语言表达形式中虽有很多相同之处,但也存在着差异。这些差异来源于英汉不同的认知和社会文化背景。 相似文献
54.
Ying Gao Nina Nevala Neil J. Cronin Taija Finni 《European Journal of Sport Science》2016,16(6):747-754
Sit–stand workstations offer a potential strategy to reduce prolonged occupational sitting. This controlled intervention study examined the effects of an environmental intervention on occupational sedentary time, musculoskeletal comfort and work ability, and the usability of sit–stand workstations in office work via a self-reported questionnaire. The intervention group (n?=?24) used sit–stand workstations during the 6-month intervention period, and the control group (n?=?21) used traditional sitting workstations. The results showed that working at sit–stand workstations can reduce sitting time significantly compared to control workstations (?6.7% vs. 5.0%, p?=?.019), which is reallocated mostly to standing (r?=??0.719, p?.001). Sit–stand workstations improved perceived musculoskeletal comfort in the neck and shoulders (p?=?.028), as well as work ability (p?=?.022). The majority of intervention subjects rated sit–stand workstation adjustability as good (83.3%), and 75.0% were satisfied with the workstation. About 41.7% of the intervention participants, who were exclusively female, used the sit–stand function on a daily basis. While the environmental change alone was effective, it is likely that promoting the daily use of sit–stand workstations with counselling would lead to even more substantial positive effects. 相似文献
55.
Martin Weiss Alexandra Newman Ceri Whitmore Stephan Weiss 《European Journal of Sport Science》2016,16(4):393-401
Sprint and distance running have experienced remarkable performance improvements over the past century. Attempts to forecast running performances share an almost similarly long history but have relied so far on relatively short data series. Here, we compile a comprehensive set of season-best performances for eight Olympically contested running events. With this data set, we conduct (1) an exponential time series analysis and (2) a power-law experience curve analysis to quantify the rate of past performance improvements and to forecast future performances until the year 2100. We find that the sprint and distance running performances of women and men improve exponentially with time and converge at yearly rates of 4% ± 3% and 2% ± 2%, respectively, towards their asymptotic limits. Running performances can also be modelled with the experience curve approach, yielding learning rates of 3% ± 1% and 6% ± 2% for the women's and men's events, respectively. Long-term trends suggest that: (1) women will continue to run 10–20% slower than men, (2) 9.50 s over 100 m dash may only be broken at the end of this century and (3) several middle- and long-distance records may be broken within the next two to three decades. The prospects of witnessing a sub-2 hour marathon before 2100 remain inconclusive. Our results should be interpreted cautiously as forecasting human behaviour is intrinsically uncertain. The future season-best sprint and distance running performances will continue to scatter around the trends identified here and may yield unexpected improvements of standing world records. 相似文献
56.
周绍平 《江苏广播电视大学学报》2005,16(6):58-60
单片机开发应用中经常用到延时控制,延时控制的基本方法有纯软件、纯硬件及软硬件结合方法,它们都有各自的特点及应用范围,以1秒延时为例给出用三种方法实现的过程,并介绍了软硬件结合延时的应用实例。 相似文献
57.
李建栋 《阜阳师范学院学报(社会科学版)》2006,(3):1-3
文章通过对《文馆词林》所存两篇残敕的文本进行分析,并将其与历史资料对照验证,得出此二敕的作者均为唐太宗,此二敕的写作时间分别为贞观二年(528)正月、三月。 相似文献
58.
Fibonacci数列与对角形行列式 总被引:1,自引:0,他引:1
杨长恩 《咸阳师范学院学报》2007,22(4):3-5,11
通过对Fibonacci数列与对角形行列式的研究,得到了它们之间的密切关系。 相似文献
59.
60.
李萍 《黄河科技大学学报》2003,5(2):124-126
网络时代,高校师生的学习方式和生活方式发生了深刻变化。互联网在促进教育发展和人才培养的同时,对学生的消极影响不容忽视。要多方面加强思想政治工作,如开辟网上“思想政治教育课堂”、设置“网上德育阵地”、建立信息监控等。 相似文献