Precipitation is the major driver of ecosystem functions and processes in semiarid and arid regions. In such waterlimited ecosystems, pulsed water inputs directly control the belowground processes through a series of ...Precipitation is the major driver of ecosystem functions and processes in semiarid and arid regions. In such waterlimited ecosystems, pulsed water inputs directly control the belowground processes through a series of soil drying and rewetting cycles. To investigate the effects of sporadic addition of water on soil CO2 effux, an artificial precipitation event （3 mm） was applied to a desert shrub ecosystem in the Mu Us Sand Land of the Ordos Plateau in China. Soil respiration rate increased 2.8 4.1 times immediately after adding water in the field, and then it returned to background level within 48 h. During the experiment, soil CO2 production was between 2 047.0 and 7 383.0 mg m^-2. In the shrubland, soil respiration responses showed spatial variations, having stronger pulse effects beneath the shrubs than in the interplant spaces. The spatial variation of the soil respiration responses was closely related with the heterogeneity of soil substrate availability. Apart from precipitation, soil organic carbon and total nitrogen pool were also identified as determinants of soil CO2 loss in desert ecosystems.展开更多
Intra-articular coronal fractures （Hoffas fractures） of distal femur are rare. Although bicondylar involvement in these fractures has been reported in the literature in association with high velocity traumata, the o...Intra-articular coronal fractures （Hoffas fractures） of distal femur are rare. Although bicondylar involvement in these fractures has been reported in the literature in association with high velocity traumata, the occurrence of these fractures involving extensor mechanism rupture and avulsion ofipsilateral tibial spine is extremely rare. To our acquaintance, such a fracture pattern has not yet been reported in the literature so far. In this article, we report one such case and discuss the importance of early diagnosis and prompt internal fixation in the management of such cases.We believe that these rare combinations of injuries should be treated aggressively by early open reduction and anatomic rigid internal fixation in order to achieve good recovery of function.展开更多
基金Project supported by the National Natural Science Foundation of China (Nos. 40730105, 40501072 and 40673067)the National Key Basic Research Program (973 Program) of China (No. 2002CB412503)the Knowledge Innovation Program of the Chinese Academy of Sciences (No. KZCX2-YW-149)
文摘Precipitation is the major driver of ecosystem functions and processes in semiarid and arid regions. In such waterlimited ecosystems, pulsed water inputs directly control the belowground processes through a series of soil drying and rewetting cycles. To investigate the effects of sporadic addition of water on soil CO2 effux, an artificial precipitation event （3 mm） was applied to a desert shrub ecosystem in the Mu Us Sand Land of the Ordos Plateau in China. Soil respiration rate increased 2.8 4.1 times immediately after adding water in the field, and then it returned to background level within 48 h. During the experiment, soil CO2 production was between 2 047.0 and 7 383.0 mg m^-2. In the shrubland, soil respiration responses showed spatial variations, having stronger pulse effects beneath the shrubs than in the interplant spaces. The spatial variation of the soil respiration responses was closely related with the heterogeneity of soil substrate availability. Apart from precipitation, soil organic carbon and total nitrogen pool were also identified as determinants of soil CO2 loss in desert ecosystems.
文摘Intra-articular coronal fractures （Hoffas fractures） of distal femur are rare. Although bicondylar involvement in these fractures has been reported in the literature in association with high velocity traumata, the occurrence of these fractures involving extensor mechanism rupture and avulsion ofipsilateral tibial spine is extremely rare. To our acquaintance, such a fracture pattern has not yet been reported in the literature so far. In this article, we report one such case and discuss the importance of early diagnosis and prompt internal fixation in the management of such cases.We believe that these rare combinations of injuries should be treated aggressively by early open reduction and anatomic rigid internal fixation in order to achieve good recovery of function.
