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.     

高中体育与健康课程评价问题思考

模块评价是新课程下普通高中体育与健康课程模块教学实施的基本保证,也是学生体育与健康课程学业评价实施的重要环节。本文分析了目前模块评价实施中存在的主要问题,探讨了新课程下体育与健康课程模块学业评价实施中操作层面的问题,以期为体育与健康课程评价改革的有效实施提供参考。     

Flowery Flour Buns （Huamo）

Shanxi, located in the Loess Plateau of North China, is one of the birthplaces of Chinese civilization. Over the sweep of history, local people used their wisdom and creativity to make flower-shaped steamed buns in various designs. Today, dough figurines in Dingxiang and flowery flour buns in Jinnan have been inscribed on China＇s national list for the protection of intangible cultural heritage.     

INTANGIBLE CULTURAl HERITAGE GOES DIGITAL “Experience the Heritage： Digital Exhibition on China＇s Intangible Culanral” Heritage held in Capital Museum

“Experience the Heritage： Digital Exhibition on China＇s Intangible Cultural Heritage” was recentlyheld in the Capital Museum in Beijing, as part of the celebrations to mark the 6fth annual Cultural Heritage Day.     

The effect of single and repeated bouts of prolonged cycling and circadian variation on saliva flow rate, immunoglobulin A and alpha-amylase responses

The purpose of this study was to establish the effect of exercise at different times of day on saliva flow rate, immunoglobulin A (sIgA) concentration and secretion rate, and alpha-amylase activity, and to establish how these parameters change following a second exercise bout performed on the same day. In a counterbalanced design, eight male volunteers participated in three experimental trials separated by at least 4 days. On the trial with afternoon exercise only, the participants cycled for 2 h at 60% VO2max starting at 14:00 h. On the other two trials, participants performed either two bouts of exercise at 60% VO2max for 2 h (the first started at 09:00 h and the second started at 14:00 h) or a separate resting trial. Unstimulated saliva samples were obtained 10 min before exercise, after 58 - 60 min and during the last 2 min of exercise, and at 1 h and 2 h after exercise. Venous blood samples were taken 5 min before exercise and immediately after exercise for both bouts. Participants remained fasted between 23:00 h on the day before the trials and 18:00 h on the day of the trial. Circadian variations were found in sIgA concentration, which decreased with time from its highest value in the early morning to its lowest value in the evening, and salivary alpha-amylase secretion rate, which increased from its lowest value in the morning to its highest value in the late afternoon. Cycling at 60% VO2max for 2 h significantly decreased saliva flow rate, increased sIgA concentration and alpha-amylase activity, but did not influence sIgA secretion rate. Performing prolonged cycling at different times of day did not differentially affect the salivary and plasma hormonal responses in the short term. Performance of a second prolonged exercise bout elicited a greater plasma stress hormone response but did not appear to compromise oral immunity acutely. These findings also suggest that, in terms of saliva secretion, sIgA and alpha-amylase responses, a 3 h rest is enough to recover from previous strenuous exercise. During such exercise, sympathetic stimulation appears to be strong enough to inhibit saliva flow rate; however, it appears that it does not increase sIgA output via transcytosis.     

String vibration dampers do not reduce racket frame vibration transfer to the forearm

In this study, we examined the effect of string vibration damping devices on reducing racket frame vibration transfer to the forearm. Twenty participants volunteered to hold a tennis racket stationary in a forehand and backhand stroking position while tennis balls were fired at 20 m x s(-1) towards two impact locations, the node of vibration and the dead spot. A three-way analysis of variance with repeated measures on damping condition, impact location and stroke condition was performed on the data. The resonant frequency of the hand-held racket was found to be approximately 120 Hz. No significant differences in amplitude of vibration at the resonant frequency were found for the wrist or the elbow when damped and non-damped impacts were compared. Impacts at the dead spot produced greater amplitudes of vibration (P < 0.01) but no interaction between impact location and string dampers was evident. The string dampers had no effect on the grip force used or the muscle electrical activity in the forearm after impact. In conclusion, we found that string dampers do not reduce the amount of racket frame vibration received at the forearm. We suggest that string dampers remain a popular accessory among tennis players because of their acoustic effects and psychological support rather than any mechanical advantage.     

China International Gallery Expo Held in Beijing

The 4th China International Gallery Exposition （CIGE） was successfully concluded on May 6 in Beijing. This five-day event is generally considered China＇s largest and best platform to showcase and trade top-class art works from home and abroad.[第一段]     

CHINA, US VOW TO BUILD CLOSER CULTURAL TIES

＂Cultural relations comprise an important part of China-US relationship. Steady and buoyant cultural exchanges help to ensure the healthy development of the bilateral pofitical and economic relations. Cultural ties at the governmental dimension should be given top priority when handling the bilateral cultural relations. The visit by the US President＇s Committee on the Arts and Humanities （PCAH） represents a landmark progress in the bilateral cultural relations at the governmental level, indicating the attitude of great support and active promotion of China-US cultural ties by the two governments and official institutions of the two nations.＂ -- Sun Jiazheng, Chinese Cultural Minister