The negative freeboard of sea ice(i.e., the height of ice surface below sea level) with subsequent flooding is widespread in the Southern Ocean, as opposed to the Arctic, due to the relatively thicker ice and thinner ...The negative freeboard of sea ice(i.e., the height of ice surface below sea level) with subsequent flooding is widespread in the Southern Ocean, as opposed to the Arctic, due to the relatively thicker ice and thinner snow. In this study, we used the observations of snow and ice thickness from 103 ice mass balance buoys(IMBs) and NASA Operation IceBridge Aircraft Missions to investigate the spatial distribution of negative freeboard of Arctic sea ice. The Result showed that seven IMBs recorded negative freeboards, which were sporadically located in the seas around Northeast Greenland, the Central Arctic Ocean, and the marginal areas of the Chukchi–Beaufort Sea. The observed maximum values of negative freeboard could reach-0.12 m in the seas around Northeast Greenland. The observations from IceBridge campaigns also revealed negative freeboard comparable to those of IMBs in the seas around North Greenland and the Beaufort Sea. We further investigated the large-scale distribution of negative freeboard using NASA CryoSat-2 radar altimeter data, and the result indicates that except for the negative freeboard areas observed by IMBs and IceBridge, there are negative freeboards in other marginal seas of the Arctic Ocean. However, the comparison of the satellite data with the IMB data and IceBridge data shows that the Cryosat-2 data generally overestimate the extent and magnitude of the negative freeboard in the Arctic.展开更多
目的:系统评价承气汤类方治疗术后胃肠功能障碍的临床疗效及安全性。方法:利用中国知网(CNKI)、万方(WanFang)、维普(VIP)、Pubmed、Sinomed、Embase、Web of Science等数据库,检索有关承气汤类方治疗术后胃肠功能障碍的随机对照试验,...目的:系统评价承气汤类方治疗术后胃肠功能障碍的临床疗效及安全性。方法:利用中国知网(CNKI)、万方(WanFang)、维普(VIP)、Pubmed、Sinomed、Embase、Web of Science等数据库,检索有关承气汤类方治疗术后胃肠功能障碍的随机对照试验,检索时间从建库至2023年4月。文献质量采用Cochrane Handbook中的偏倚风险工具进行评估,使用Review Manager 5.3、Stata 12.0软件进行Meta分析。结果:最终纳入35篇文献,共计3552例患者,Meta分析结果显示,与对照组相比,治疗组术后排气时间、排便时间、肠鸣音恢复时间、饮食恢复时间、总有效率均较优,差异具有统计学意义(P<0.05)。结论:承气汤类方对术后胃肠功能障碍治疗具有较好的临床疗效和安全性,但还需纳入更多高质量的研究以进一步验证。展开更多
基金supported by the National Key Research and Development Program of China (No. 2018YFC1406104)the National Natural Science Foundation of China (Nos. 41425003 and 41971084)。
文摘The negative freeboard of sea ice(i.e., the height of ice surface below sea level) with subsequent flooding is widespread in the Southern Ocean, as opposed to the Arctic, due to the relatively thicker ice and thinner snow. In this study, we used the observations of snow and ice thickness from 103 ice mass balance buoys(IMBs) and NASA Operation IceBridge Aircraft Missions to investigate the spatial distribution of negative freeboard of Arctic sea ice. The Result showed that seven IMBs recorded negative freeboards, which were sporadically located in the seas around Northeast Greenland, the Central Arctic Ocean, and the marginal areas of the Chukchi–Beaufort Sea. The observed maximum values of negative freeboard could reach-0.12 m in the seas around Northeast Greenland. The observations from IceBridge campaigns also revealed negative freeboard comparable to those of IMBs in the seas around North Greenland and the Beaufort Sea. We further investigated the large-scale distribution of negative freeboard using NASA CryoSat-2 radar altimeter data, and the result indicates that except for the negative freeboard areas observed by IMBs and IceBridge, there are negative freeboards in other marginal seas of the Arctic Ocean. However, the comparison of the satellite data with the IMB data and IceBridge data shows that the Cryosat-2 data generally overestimate the extent and magnitude of the negative freeboard in the Arctic.
