Using the data observed by 62 Chinese Routine Meteorological Stations (CRMS) with long term radiation observation, the climatic trends and the relationship between pan-evaporation and its environmental factors are ana...Using the data observed by 62 Chinese Routine Meteorological Stations (CRMS) with long term radiation observation, the climatic trends and the relationship between pan-evaporation and its environmental factors are analyzed comprehensively. The results show that during the last 40 years, the relative humidity is uptrend in west China, downtrend in east China, and their extrema are 0.20%/a and ?0.22%/a respectively; the precipitations of about 61% CRMS keep uptrend, its maximum can reach 10.52 mm/a2 while the cloud amounts of about 79% CRMS keep downtrend slightly. About 98% CRMS display the air temperature uptrend, and the maximum is 0.11℃/a. About 76% CRMS display the land surface temperature uptrend. About 87% CRMS show the daily range of temperature downtrend. The global radiations observed by about 85% CRMS and the 10 m wind speeds observed by about 77% CRMS hold downtrend. The annual pan-evaporations of about 66% CRMS hold descend trend, and the biggest descent reaches ?24.9 mm/a2. The pan-evaporation has good relationship with many environmental factors, but the relationship with the relative humidity is the best. All of the climatic trends respond to the global climate changes.展开更多
Despite the observed increase in global temperature, observed pan evaporation in many regions has been decreasing over the past 50 years, which is known as the ＂pan evaporation paradox＂. The ＂pan evaporation parado...Despite the observed increase in global temperature, observed pan evaporation in many regions has been decreasing over the past 50 years, which is known as the ＂pan evaporation paradox＂. The ＂pan evaporation paradox＂ also exists in the Tibetan Plateau, where pan evaporation has decreased by 3.06 mm a-2 （millimeter per annum）. It is necessary to explain the mechanisms behind the observed decline in pan evaporation because the Tibetan Plateau strongly influences climatic and environmental changes in China, Asia and even in the Northern Hemisphere. In this paper, a derivation based approach has been used to quantitatively assess the contribution rate of climate factors to the observed pan evaporation trend across the Tibetan Plateau. The results showed that, provided the other factors remain constant, the increasing temperature should have led to a 2.73 mm a-2 increase in pan evaporation annually, while change in wind speed, vapor pressure and solar radiation should have led to a decrease in pan evaporation by 2.81 mm a-2, 1.96 mm a-2 and 1.11 mm a-2 respectively from 1970 to 2005. The combined effects of the four climate variables have resulted in a 3.15 mm a-2 decrease in pan evaporation, which is close to the observed pan evaporation trend with a relative error of 2.94%. A decrease in wind speed was the dominant factor for the decreasing pan evaporation, followed by an increasing vapor pressure and decreasing solar radiation, all of which offset the effect of increasing temperature across the Tibetan Plateau.展开更多
采用连续实验装置与工艺,借助密度、X射线衍射、红外光谱、元素分析等技术,研究了聚丙烯腈共聚纤维在连续预氧化过程中密度与结构之间的关系及有关反应过程与影响因素.研究结果表明,预氧化过程中 PAN 共聚纤维密度的变化不仅可反映出纤...采用连续实验装置与工艺,借助密度、X射线衍射、红外光谱、元素分析等技术,研究了聚丙烯腈共聚纤维在连续预氧化过程中密度与结构之间的关系及有关反应过程与影响因素.研究结果表明,预氧化过程中 PAN 共聚纤维密度的变化不仅可反映出纤维结构上的各种化学和物理变化,亦可以作为一种工业生产的控制指标.展开更多
AIM: To study the safety of epidural anesthesia(EA),its effect on pancreatic perfusion and the outcome of patients with acute pancreatitis(AP).METHODS: From 2005 to August 2010,patients with predicted severe AP [Ranso...AIM: To study the safety of epidural anesthesia(EA),its effect on pancreatic perfusion and the outcome of patients with acute pancreatitis(AP).METHODS: From 2005 to August 2010,patients with predicted severe AP [Ranson score ≥ 2,C-reactive protein > 100 or necrosis on computed tomography(CT)] were prospectively randomized to either a group receiving EA or a control group treated by patientcontrolled intravenous analgesia. Pain management was evaluated in the two groups every eight hours using the visual analog pain scale(VAS). Parameters for clinical severity such as length of hospital stay,use of antibiotics,admission to the intensive care unit,radiological/clinical complications and the need for surgical necrosectomy including biochemical data were recorded. A CT scan using a perfusion protocol was performed on admission and at 72 h to evaluate pancreatic blood flow. A significant variation in blood flow was defined as a 20% difference in pancreatic perfusion between admission and 72 h and was measured in the head,body and tail of the pancreas.RESULTS: We enrolled 35 patients. Thirteen were randomized to the EA group and 22 to the control group. There were no differences in demographic characteristics between the two groups. The Balthazar radiological severity score on admission was higher in the EA group than in the control group(mean score 4.15 ± 2.54 vs 3.38 ± 1.75,respectively,P = 0.347) and the median Ranson scores were 3.4 and 2.7 respectively(P = NS). The median duration of EA was 5.7 d,and no complications of the epidural procedure were reported. An improvement in perfusion of the pancreas was observed in 13/30(43%) of measurements in the EA group vs 2/27(7%) in the control group(P = 0.0025). Necrosectomy was performed in 1/13 patients in the EA group vs 4/22 patients in the control group(P = 0.63). The VAS improved during the first ten days in the EA group compared to the control group(0.2 vs 2.33,P = 0.034 at 10 d). Length of stay and mortality were not statistically different between the 2 groups展开更多
基金supported by the Knowledge lnnovation Program of the Chinese Academy of Sciences(Grant No.KZCX1-SW-04)the Knowledge Innovation Foundation of Cold and And Regions Environmental and Engineering Reseatch Institute(CA-REERI)the Chinese Academy of Sciences(Grant No.CACX2004117).
文摘Using the data observed by 62 Chinese Routine Meteorological Stations (CRMS) with long term radiation observation, the climatic trends and the relationship between pan-evaporation and its environmental factors are analyzed comprehensively. The results show that during the last 40 years, the relative humidity is uptrend in west China, downtrend in east China, and their extrema are 0.20%/a and ?0.22%/a respectively; the precipitations of about 61% CRMS keep uptrend, its maximum can reach 10.52 mm/a2 while the cloud amounts of about 79% CRMS keep downtrend slightly. About 98% CRMS display the air temperature uptrend, and the maximum is 0.11℃/a. About 76% CRMS display the land surface temperature uptrend. About 87% CRMS show the daily range of temperature downtrend. The global radiations observed by about 85% CRMS and the 10 m wind speeds observed by about 77% CRMS hold downtrend. The annual pan-evaporations of about 66% CRMS hold descend trend, and the biggest descent reaches ?24.9 mm/a2. The pan-evaporation has good relationship with many environmental factors, but the relationship with the relative humidity is the best. All of the climatic trends respond to the global climate changes.
基金The European Commission (Call FP7-ENV-2007-1), No.212921National Basic Research Program of China, No.2010CB428406
文摘Despite the observed increase in global temperature, observed pan evaporation in many regions has been decreasing over the past 50 years, which is known as the ＂pan evaporation paradox＂. The ＂pan evaporation paradox＂ also exists in the Tibetan Plateau, where pan evaporation has decreased by 3.06 mm a-2 （millimeter per annum）. It is necessary to explain the mechanisms behind the observed decline in pan evaporation because the Tibetan Plateau strongly influences climatic and environmental changes in China, Asia and even in the Northern Hemisphere. In this paper, a derivation based approach has been used to quantitatively assess the contribution rate of climate factors to the observed pan evaporation trend across the Tibetan Plateau. The results showed that, provided the other factors remain constant, the increasing temperature should have led to a 2.73 mm a-2 increase in pan evaporation annually, while change in wind speed, vapor pressure and solar radiation should have led to a decrease in pan evaporation by 2.81 mm a-2, 1.96 mm a-2 and 1.11 mm a-2 respectively from 1970 to 2005. The combined effects of the four climate variables have resulted in a 3.15 mm a-2 decrease in pan evaporation, which is close to the observed pan evaporation trend with a relative error of 2.94%. A decrease in wind speed was the dominant factor for the decreasing pan evaporation, followed by an increasing vapor pressure and decreasing solar radiation, all of which offset the effect of increasing temperature across the Tibetan Plateau.
基金Supported by a research grant of the University Hospitals of Geneva(to Bühler L)
文摘AIM: To study the safety of epidural anesthesia(EA),its effect on pancreatic perfusion and the outcome of patients with acute pancreatitis(AP).METHODS: From 2005 to August 2010,patients with predicted severe AP [Ranson score ≥ 2,C-reactive protein > 100 or necrosis on computed tomography(CT)] were prospectively randomized to either a group receiving EA or a control group treated by patientcontrolled intravenous analgesia. Pain management was evaluated in the two groups every eight hours using the visual analog pain scale(VAS). Parameters for clinical severity such as length of hospital stay,use of antibiotics,admission to the intensive care unit,radiological/clinical complications and the need for surgical necrosectomy including biochemical data were recorded. A CT scan using a perfusion protocol was performed on admission and at 72 h to evaluate pancreatic blood flow. A significant variation in blood flow was defined as a 20% difference in pancreatic perfusion between admission and 72 h and was measured in the head,body and tail of the pancreas.RESULTS: We enrolled 35 patients. Thirteen were randomized to the EA group and 22 to the control group. There were no differences in demographic characteristics between the two groups. The Balthazar radiological severity score on admission was higher in the EA group than in the control group(mean score 4.15 ± 2.54 vs 3.38 ± 1.75,respectively,P = 0.347) and the median Ranson scores were 3.4 and 2.7 respectively(P = NS). The median duration of EA was 5.7 d,and no complications of the epidural procedure were reported. An improvement in perfusion of the pancreas was observed in 13/30(43%) of measurements in the EA group vs 2/27(7%) in the control group(P = 0.0025). Necrosectomy was performed in 1/13 patients in the EA group vs 4/22 patients in the control group(P = 0.63). The VAS improved during the first ten days in the EA group compared to the control group(0.2 vs 2.33,P = 0.034 at 10 d). Length of stay and mortality were not statistically different between the 2 groups
