Ski and the closely related SnoN were discovered as oncogenes by their ability to transform chicken embryo fibroblasts upon overexpression. While elevated expressions of Ski and SnoN have also been reported in many hu...Ski and the closely related SnoN were discovered as oncogenes by their ability to transform chicken embryo fibroblasts upon overexpression. While elevated expressions of Ski and SnoN have also been reported in many human cancer cells and tissues, consistent with their pro-oncogenic activity, emerging evidence also suggests a potential anti-oncogenic activity for both. In addition, Ski and SnoN have been implicated in regulation of cell differentiation, especially in the muscle and neuronal lineages. Multiple cellular partners of Ski and SnoN have been identifed in an effort to understand the molecular mechanisms underlying the complex roles of Ski and SnoN. In this review, we summarize recent findings on the biological functions of Ski and SnoN, their mechanisms of action and how their levels of expression are regulated.展开更多
A general mathematical model of carrier-based aircraft ski jump take-off is derived based on tensor. The carrier, the aircraft body and the movable parts of the landing gears are treated as independent entities. These...A general mathematical model of carrier-based aircraft ski jump take-off is derived based on tensor. The carrier, the aircraft body and the movable parts of the landing gears are treated as independent entities. These entities are assembled into a multi-rigid-body system with flexible links. Dynamical equations of each entity are derived on the basis of the Newton law and the Euler transformation. Using the invariance property of the tensor, the dynamical and kinematical equations are converted to tensor forms which are invariant under time-dependent coordinate transformations. Then the tensor-formed equations are expressed by the matrix operation. Differential equation group of the matrix form is formulated for the programming. The closure of the model is discussed, and the simulation results are given.展开更多
以Web of Science TM核心合集收录的2006年以来"滑雪运动风险"为研究主题的357篇文献作为数据来源,利用CitespaceⅤ软件进行可视化处理与分析。以知识图谱可视化的方式梳理冰雪运动风险研究的国家、学科分布和研究热点,分析...以Web of Science TM核心合集收录的2006年以来"滑雪运动风险"为研究主题的357篇文献作为数据来源,利用CitespaceⅤ软件进行可视化处理与分析。以知识图谱可视化的方式梳理冰雪运动风险研究的国家、学科分布和研究热点,分析滑雪运动风险的研究脉络,探讨滑雪运动风险的研究进展,把握滑雪运动风险的研究前沿,以推动我国滑雪运动风险的理论和实践的发展。结果表明:国外滑雪风险研究主要集中在欧洲的阿尔卑斯山区和北美地区的美国东北部和中西部以及阿拉斯加、加拿大的落基山脉等区域。国外滑雪运动风险的研究不仅仅局限于体育领域,以体育科学为主导,与公众环境与职业保健、社会学、骨科学、心理学、生态学、外科学、工程学、休闲学与经济学等学科构成交叉。国外滑雪运动风险研究的热点紧紧围绕着滑雪运动中的风险展开,包括损伤、风险因素、流行性病学、儿童、运动、头部损伤等不同的伤病和风险因素;在研究对象上,儿童也开始备受重视。展开更多
Ski tourism is extremely sensitive to climate change and is also heavily affected by socioeconomic conditions.Although some ski areas arestill profitable under current climate and socioeconomic conditions,they will be...Ski tourism is extremely sensitive to climate change and is also heavily affected by socioeconomic conditions.Although some ski areas arestill profitable under current climate and socioeconomic conditions,they will become difficult to operate in the face of rising winter temper-atures,which will result in further economic losses,resource waste and environmental damage.This study projects variability in the suitability ofski area development across China in the coming decades.Natural suitability under three representative concentration pathway emission sce-narios(RCP2.6,RCP4.5 and RCP8.5),socioeconomic suitability under four shared socioeconomic pathways(SSP1,SSP2,SSP3,and SSP5)andintegrated suitability under four climatic-socioeconomic scenarios(RCP2.6-SSP1,RCP4.5-SSP2,RCP8.5-SSP3,and RCP8.5-SSP5)are re-ported.Furthermore,the suitability of 731 existing ski areas in China is assessed.The results show a substantial decline in integrated suitabilityfor most regions of China except for some very cold areas,where higher air temperatures will make visitors feel more comfortable and therelatively poor socioeconomic conditions will improve in the 2030s,2050s and 2090s.The average higher integrated suitability area(integratedsuitability values greater than 0.5)under four climatic-socioeconomic scenarios decreases from the current 29.9%e14.4%,5.0%and 4.5%bythe 2030s,2050s and 2090s,respectively.Under RCP2.6-SSP1,the higher integrated suitability area is projected to decrease from the current28.0%e5.2%by the 2050s and then increase to 5.3%by the 2090s.Under RCP4.5-SSP2,RCP8.5-SSP3,and RCP8.5-SSP5,the higher inte-grated suitability area is projected to continuously decrease from 30.3%,30.6%and 30.6%in the 2010s to 4.1%,4.4%and 4.4%in the 2090s,respectively.By the 2090s,41,138 and 277 existing ski areas are projected to be closed under RCP2.6-SSP1,RCP4.5-SSP2,and RCP8.5-SSP3/RCP8.5-SSP5,respectively.It is clear that emission pathways and climate change adaptation and mitigation strategies will greatly shape thedevelopment of展开更多
The development of ice-and-snow tourism (IST) has great potential for poverty alleviation and is of great significance for promoting the sustainable development of alpine areas. However, little attention has been give...The development of ice-and-snow tourism (IST) has great potential for poverty alleviation and is of great significance for promoting the sustainable development of alpine areas. However, little attention has been given to evaluating the suitability and potential of ice-and-snow tourism in poverty-stricken areas. Taking 832 poverty-stricken counties in China as samples, this study proposed an integrity suitability index (ISI) based on natural and socioeconomic factors to evaluate the suitability and potential of developing ice-and-snow tourism in poverty-stricken counties. The results showed that there are significant differences between the spatial distributions of the suitability of glacier- and ski-related tourism. The former is mainly distributed in the Qinghai‒Tibet Plateau, while the latter is distributed in low-altitude mountainous areas. Additionally, 36.0% of the total number of poverty-stricken counties have the potential to match medium-to high-level ISIs of ice-and-snow tourism, of which 2.5%, 32.9% and 0.2% are suitable for glacier excursions, ski sports and both, respectively. Furthermore, climate change and environmental protection are the main constraints on the development of ice-and-snow tourism and corresponding development strategies are proposed. This study can provide references for scientific planning and policy making regarding the sustainable development in poverty-stricken areas.展开更多
Purpose： The aims of this study were to assess differences of limb symmetry index （LSI） in strength- and coordination-related tasks between high-level, competitive, noninjured ski racers of different age-related pe...Purpose： The aims of this study were to assess differences of limb symmetry index （LSI） in strength- and coordination-related tasks between high-level, competitive, noninjured ski racers of different age-related performance levels and to prospectively assess limb differences as a possible risk factor for traumatic and overuse injury in youth ski racers. Methods： The study （Study 1） included 285 high-level competitive ski racers （125 females, 160 males） of 3 age-related performance levels and based on the school system： 95 youth （10-14 years, secondary modem school）, 107 adolescent （15-19 years, grammar school）, and 83 elite athletes （20-34 years）. To investigate the second aim （Study 2）, 67 of the 95 youth athletes were included and any traumatic or overuse injuries were prospectively recorded over 2 seasons. All athletes performed 4 unilateral tests （strength related： one-leg counter movement jump （OL-CMJ） and one-leg isometric/isokinetic press strength test （OL-ILS）; coordination related： one-leg stability test （OL-ST） and one-leg speedy jump test （OL-SJ））. The LSI was calculated by dividing the dominant leg by the nondominant leg and multiplying by 100. Kruskal-Wallis H tests and binary logistic regression analyses were conducted. Results： There were significant differences between the LSI of the 3 age-related performance-level groups only in the strength-related tests： the OL-CMJ （X^2（2, 285） = 9.09; p = 0.01） and the OL-ILS （X^2（2,285） = 14.79; p 〈 0.01）. The LSI for OL-ILS was found to be a significant risk factor for traumatic injury in youth ski racers （Wald = 7.08; p 〈 0.01）. No significant risk factors were found for overuse injuries. Conclusion： Younger athletes display slightly greater LSI values only in the strength-related tests. The cut-off value of limb differences of 〈 10% for return to sport decisions seems to be appropriate for elite athletes, but for youth and adolescent athletes it has to be critically d展开更多
文摘Ski and the closely related SnoN were discovered as oncogenes by their ability to transform chicken embryo fibroblasts upon overexpression. While elevated expressions of Ski and SnoN have also been reported in many human cancer cells and tissues, consistent with their pro-oncogenic activity, emerging evidence also suggests a potential anti-oncogenic activity for both. In addition, Ski and SnoN have been implicated in regulation of cell differentiation, especially in the muscle and neuronal lineages. Multiple cellular partners of Ski and SnoN have been identifed in an effort to understand the molecular mechanisms underlying the complex roles of Ski and SnoN. In this review, we summarize recent findings on the biological functions of Ski and SnoN, their mechanisms of action and how their levels of expression are regulated.
文摘A general mathematical model of carrier-based aircraft ski jump take-off is derived based on tensor. The carrier, the aircraft body and the movable parts of the landing gears are treated as independent entities. These entities are assembled into a multi-rigid-body system with flexible links. Dynamical equations of each entity are derived on the basis of the Newton law and the Euler transformation. Using the invariance property of the tensor, the dynamical and kinematical equations are converted to tensor forms which are invariant under time-dependent coordinate transformations. Then the tensor-formed equations are expressed by the matrix operation. Differential equation group of the matrix form is formulated for the programming. The closure of the model is discussed, and the simulation results are given.
文摘以Web of Science TM核心合集收录的2006年以来"滑雪运动风险"为研究主题的357篇文献作为数据来源,利用CitespaceⅤ软件进行可视化处理与分析。以知识图谱可视化的方式梳理冰雪运动风险研究的国家、学科分布和研究热点,分析滑雪运动风险的研究脉络,探讨滑雪运动风险的研究进展,把握滑雪运动风险的研究前沿,以推动我国滑雪运动风险的理论和实践的发展。结果表明:国外滑雪风险研究主要集中在欧洲的阿尔卑斯山区和北美地区的美国东北部和中西部以及阿拉斯加、加拿大的落基山脉等区域。国外滑雪运动风险的研究不仅仅局限于体育领域,以体育科学为主导,与公众环境与职业保健、社会学、骨科学、心理学、生态学、外科学、工程学、休闲学与经济学等学科构成交叉。国外滑雪运动风险研究的热点紧紧围绕着滑雪运动中的风险展开,包括损伤、风险因素、流行性病学、儿童、运动、头部损伤等不同的伤病和风险因素;在研究对象上,儿童也开始备受重视。
基金the National Natural Science Foundation of China(41690140 and 41771389)the National Foundational Scientific and Technological Work Programs of the Ministry of Science and Technology of China(2017FY100501).
文摘Ski tourism is extremely sensitive to climate change and is also heavily affected by socioeconomic conditions.Although some ski areas arestill profitable under current climate and socioeconomic conditions,they will become difficult to operate in the face of rising winter temper-atures,which will result in further economic losses,resource waste and environmental damage.This study projects variability in the suitability ofski area development across China in the coming decades.Natural suitability under three representative concentration pathway emission sce-narios(RCP2.6,RCP4.5 and RCP8.5),socioeconomic suitability under four shared socioeconomic pathways(SSP1,SSP2,SSP3,and SSP5)andintegrated suitability under four climatic-socioeconomic scenarios(RCP2.6-SSP1,RCP4.5-SSP2,RCP8.5-SSP3,and RCP8.5-SSP5)are re-ported.Furthermore,the suitability of 731 existing ski areas in China is assessed.The results show a substantial decline in integrated suitabilityfor most regions of China except for some very cold areas,where higher air temperatures will make visitors feel more comfortable and therelatively poor socioeconomic conditions will improve in the 2030s,2050s and 2090s.The average higher integrated suitability area(integratedsuitability values greater than 0.5)under four climatic-socioeconomic scenarios decreases from the current 29.9%e14.4%,5.0%and 4.5%bythe 2030s,2050s and 2090s,respectively.Under RCP2.6-SSP1,the higher integrated suitability area is projected to decrease from the current28.0%e5.2%by the 2050s and then increase to 5.3%by the 2090s.Under RCP4.5-SSP2,RCP8.5-SSP3,and RCP8.5-SSP5,the higher inte-grated suitability area is projected to continuously decrease from 30.3%,30.6%and 30.6%in the 2010s to 4.1%,4.4%and 4.4%in the 2090s,respectively.By the 2090s,41,138 and 277 existing ski areas are projected to be closed under RCP2.6-SSP1,RCP4.5-SSP2,and RCP8.5-SSP3/RCP8.5-SSP5,respectively.It is clear that emission pathways and climate change adaptation and mitigation strategies will greatly shape thedevelopment of
基金This work was supported by National Natural Science Foundation of China(41690145,41671058)Beijing Normal University Talent Introduction Project of China(12807-312232101).
文摘The development of ice-and-snow tourism (IST) has great potential for poverty alleviation and is of great significance for promoting the sustainable development of alpine areas. However, little attention has been given to evaluating the suitability and potential of ice-and-snow tourism in poverty-stricken areas. Taking 832 poverty-stricken counties in China as samples, this study proposed an integrity suitability index (ISI) based on natural and socioeconomic factors to evaluate the suitability and potential of developing ice-and-snow tourism in poverty-stricken counties. The results showed that there are significant differences between the spatial distributions of the suitability of glacier- and ski-related tourism. The former is mainly distributed in the Qinghai‒Tibet Plateau, while the latter is distributed in low-altitude mountainous areas. Additionally, 36.0% of the total number of poverty-stricken counties have the potential to match medium-to high-level ISIs of ice-and-snow tourism, of which 2.5%, 32.9% and 0.2% are suitable for glacier excursions, ski sports and both, respectively. Furthermore, climate change and environmental protection are the main constraints on the development of ice-and-snow tourism and corresponding development strategies are proposed. This study can provide references for scientific planning and policy making regarding the sustainable development in poverty-stricken areas.
文摘Purpose： The aims of this study were to assess differences of limb symmetry index （LSI） in strength- and coordination-related tasks between high-level, competitive, noninjured ski racers of different age-related performance levels and to prospectively assess limb differences as a possible risk factor for traumatic and overuse injury in youth ski racers. Methods： The study （Study 1） included 285 high-level competitive ski racers （125 females, 160 males） of 3 age-related performance levels and based on the school system： 95 youth （10-14 years, secondary modem school）, 107 adolescent （15-19 years, grammar school）, and 83 elite athletes （20-34 years）. To investigate the second aim （Study 2）, 67 of the 95 youth athletes were included and any traumatic or overuse injuries were prospectively recorded over 2 seasons. All athletes performed 4 unilateral tests （strength related： one-leg counter movement jump （OL-CMJ） and one-leg isometric/isokinetic press strength test （OL-ILS）; coordination related： one-leg stability test （OL-ST） and one-leg speedy jump test （OL-SJ））. The LSI was calculated by dividing the dominant leg by the nondominant leg and multiplying by 100. Kruskal-Wallis H tests and binary logistic regression analyses were conducted. Results： There were significant differences between the LSI of the 3 age-related performance-level groups only in the strength-related tests： the OL-CMJ （X^2（2, 285） = 9.09; p = 0.01） and the OL-ILS （X^2（2,285） = 14.79; p 〈 0.01）. The LSI for OL-ILS was found to be a significant risk factor for traumatic injury in youth ski racers （Wald = 7.08; p 〈 0.01）. No significant risk factors were found for overuse injuries. Conclusion： Younger athletes display slightly greater LSI values only in the strength-related tests. The cut-off value of limb differences of 〈 10% for return to sport decisions seems to be appropriate for elite athletes, but for youth and adolescent athletes it has to be critically d
