北京的绿色宣言

Beijing Organizing Committee of the 2008 Olympic Games (BOCOG) released a draft of the Ecological Environment Protection Plan on September 6.The Ecological Environment Protection Plan, a part of the "Beijing Olympic Action Plan", will serve as the guideline for the city's environmental development in the next six years.The draft plan, which is composed of six parts, is subject to public opinions In the following month, said BOCOG. BOCOG will revise the draft in accordance with the public opinionsand then work out the final edition.     

知识服务:在新职业中的文件信息管理工作

一、知识服务作为一种新的职业正在兴起信息管理领域正在兴起一种新职业——知识服务,我们把该职业定位成一种把知识管理、信息管理和战略(以业绩为中心)学习与培训联系到一起的职业。对组织来说,知识服务为企业领域提供了一种保证组织活动成功的管理方法。     

关于乒乓球选材标准的教练员观点调查

本研究的目的是基于乒乓球教练员对人体形态测量、身体素质能力、生理心理素质、心理以及体型因素的基础上,决定选材的原则和标准。这个研究的反馈者包括40名国际水平的乒乓球教练员(26位来自伊朗,14位来自其它国家),他们是随机抽取的,55%的反馈者持有国际教练员资格学位,教练生涯的平均年数是15.74年。大约有50%的认为7～8岁是选材的最合适年龄段;27.5%认为是5～6岁;17.5%认为是9～10岁。根据分析,发现66.5%选择观察方法;48.1%选择科学方法作为选材时优先考虑的方法。总的来说,34.2%认为教育部门对于选材具有最主要的责任。进一步而言,涉及…     

气候·人类·地球

随着工业化进程脚步的加快,现代化痕迹遍布生活的每个角落,同时人类也不得不面临现代化生产给自然气候带来的不容忽视的严重影响。我们在渐渐失去冬天……     

明星与政治

Bono vs.Pretty Much Eyerything博诺vs .几乎每件事Bono befriends O’Neill and Ghana President JohnKufuor. His Case:You name it,he’s trying to fix it:hunger,education,health care,orphans,whatever makes peopleunhappy;lately,he's pushing debt relief for the ThirdWorld nations and stopping the spread of AIDS in Africa.     

三个IT厂商酿成的惨痛教训

ｋｅｙｓｔｏｎｅ公司长期停滞的ＥＲＰ项目终于宣告成功，　系统将 １３０ 个厂房，全美国２０００ 多员工连接在一起。回首ｋｅｙｓｔｏｎｅ 信息化历程，其经验教训值得我们深思。     

开放学习、开放网络北大核心CSSCI

随着大规模公开在线课程(简称"慕课")的发展和普及,在线开放学习进入了主流。然而,虽然人们对公开在线课程的兴趣比以往任何时候都要强烈,但是慕课仅是构建开放学习大环境的第一步。本文根据笔者2017年3月9日在锡拉丘兹纽约州立大学所做的报告整理而成。文章阐述影响未来开放学习的几个重要创新事件:分布式社交网络、云基础设施和虚拟化、沉浸式现实以及个人学习环境。文章还讨论了这种正在发展中的模式会给学习提供者和教育机构带来哪些挑战并提出应对这些挑战的政策和措施。     

Evaluating effects of atmospheric CO2 on stability of global climate: a cell-to-cell mapping approach

Atmospheric carbon dioxide concentration [CO2], incoming solar radiation and sea ice coverage are among the most important factors that control the global climate. By applying the simple cell-to-cell mapping technique to a simplified atmosphere-ocean-sea ice feedback climate model, effects of these factors on the stability of the climatic system are studied. The current climatic system is found to be stable but highly nonlinear. The resiliency of stability increases with [CO2] to a summit when [CO2] reaches 290 μL/L which is comparable to the pre-industrial level, suggesting carbon dioxide is essential to the stability of the global climate. With [CO2] rising further, the global climate stability decreases, the mean ocean temperature goes up and the sea ice coverage shrinks in the polar region. When the incoming solar radiation is intensified, the ice coverage gradually diminishes, but the mean ocean temperature remains relatively constant. Overall, our analysis suggests that at the current levels of three external factors the stability of global climate is highly resilient. However, there exists a possibility of extreme states of climate, such as a snow-ball earth and an ice-free earth.     

Adaptive progressive download based on the MPEG-4 file format

In this paper we describe how progressive download and adaptive streaming can be combined into a simple and efficient streaming framework. Based on the MPEG-4 file format (MP4) we use HTTP for transport and argue that these two components are sufficient for specifying an open streaming architecture. The client selects appropriate chunks from the MP4 file to be transferred based on (1) the header information (i.e. the "moov" box) in the first part of the file and (2) his observation of network throughput. The framework is completely client driven which allows for better server scalability and reduces signalling overhead. We discuss architecture and implementation issues such as complexity, interoperability and scalability and compare to 3GPP PSS Re1-6 adaptive streaming when appropriate. Measurements from a simple MP4/HTTP streaming client are presented showing that appropriate chunks are selected such that increased reliability is achieved.     

Effects of a remote,YouTube-delivered exercise intervention on young adults’physical activity,sedentary behavior,and sleep during the COVID-19 pandemic:Randomized controlled trial

Background:Public health guidelines have called for innovative and flexible physical activity(PA)intervention strategies to promote PA and health amid the coronavirus disease 2019(COVID-19)pandemic.Therefore,this study’s purpose was to examine the effects of a home-based,YouTube-delivered PA intervention grounded in self-determination theory on young adults’free-living PA,sedentary behavior,and sleep quality(NCT04499547).Methods:Sixty-four young adults(48 females;age=22.8±3.4 years,mean±SD;body mass index=23.1±2.6 kg/m²)were randomized(1:1)into the intervention group,which received weekly aerobic and muscle-strengthening PA videos,or control group,which received weekly general health education videos,for 12 weeks.Our primary outcome was free-living moderate-to-vigorous PA(MVPA)and our secondary outcomes were sedentary behavior,light PA,and sleep quality(measured using ActiGraph accelerometers)along with muscle-strengthening PA frequency,self-determination theory-related motivation(non-regulation,external regulation,introjected regulation,identified regulation,integrated regulation,and intrinsic regulation),and perceived PA barriers(assessed using validated questionnaires).Repeated measures analysis of variances(ANOVAs)examined between-group differences at an adjusted significance level of 0.004 and effect sizes as partial eta-squared(η;).Results:We observed statistically significant interaction effects for MVPA,sleep efficiency,muscle-strengthening PA frequency,non-regulation,integrated regulation,intrinsic regulation,and perceived PA barriers(F(1,62)=10.75-77.67,p<0.001-0.002,η_p²=0.15-0.56)with all outcomes favoring the intervention group.We observed no statistically significant differences in either group for sedentary behavior,light PA,sleep duration,or external,introjected,and identified regulations after 12 weeks(F(1,62)=1.11-3.64,p=0.06-0.61).Conclusion:With national COVID-19 restrictions still in place and uncertainty regarding post-pandemic PA environments and behaviors,a remote,YouTube-delivered PA intervention may help foster clinically meaningful improvements in young adults’free-living MVPA,musclestrengthening PA frequency,sleep efficiency,PA-related intrinsic motivation,and perceived PA barriers.