Extreme weather events have played an important role in driving the ecosystem dynamics in high altitude areas, but the underlying mechanism remains unclear. To understand if and how the soil processes of an ecosystem ...Extreme weather events have played an important role in driving the ecosystem dynamics in high altitude areas, but the underlying mechanism remains unclear. To understand if and how the soil processes of an ecosystem react to extreme drought, we manipulated a once-in-a-century meteorological extreme drought in an alpine meadow on the Tibetan Plateau, which is also known as the ＂forerunner of global weather changes＂. The extremity was determined by statistical extreme weather events with respect to a historical reference period from April to September during 1962 - 2004, where the local historical precipitation data was calculated and intensified to loo-year recurrent drought event with Gumbel I distribution. The indicators we measured included soil microbial biomass C/N/P and soil enzymatic activities of phosphatase （AP） disbounding organic phosphate, cellobiohydrolase （CBH）, β- glucocidase （BG）, N-releasing enzyme N-acetyl- glucosaminidase （NAG） as well as soil respirations, during and after the treatments. It was found that the manipulated event induced a rapid shift in microbial biomass and activities, indicating a lower resistance of the underground process. However, the microbial and biochemical parameters saw rapid recovery after the event, which meant the soil processes enjoyed high resilience. The high responsiveness and lag-time effects of the soil indicators rendered new horizons for us to evaluate the interaction between the extremes and the ecosystem stability. Our study indicated that the once-in-a-century extreme drought induced very short term response in the soil biotic process, and the soil processes worked to buffer against such events under the observation period.展开更多
During the course of a hypothetical severe accident in a nuclear Pressurized Water Reactor （PWR）, containment reactor is pressurized by steam and hydrogen released from a primary circuit breach and distributed into ...During the course of a hypothetical severe accident in a nuclear Pressurized Water Reactor （PWR）, containment reactor is pressurized by steam and hydrogen released from a primary circuit breach and distributed into the containment according to convective flows and steam wall condensation. In addition, core degradation leads to fission products released into the containment. Water spraying is used in the containment as mitigation means in order to reduce pressure, to remove fission products and to enhance the gas mixing in case of presence of hydrogen. This paper presents results of the TOSQAN aerosol program undertaken by the Institute de Radioprotection et de Sfiret6 Nucl6aire （IRSN） devoted to study the aerosol removal by a spray, for typical accidental thermal hydraulic conditions in PWR containment. The TOSQAN facility is a large enclosure devoted to simulate typical accidental thermal hydraulic flow conditions in nuclear PWR containment.展开更多
As a result of more than two thousand nuclear tests performed since 1945, two war actions and few accidents in nuclear reactor, it does already exist a radioactive contamination at global scale. This contamination has...As a result of more than two thousand nuclear tests performed since 1945, two war actions and few accidents in nuclear reactor, it does already exist a radioactive contamination at global scale. This contamination has been accumulated mainly in marine sediments, because sea is about 80% of planet surface, and solid fission products released by nuclear explosions are transported by wind first and then by rain to liquid and solid portions on earth, while gaseous fission products are diffused in the atmosphere. In this way, heavy, high yielding fission products, such as 137Cs, get marine sediments, where they are found mixed with heavy radioactive natural elements such as U, Th and their also radioactive decay products. But since alkaline are so abundant on earth, it is also found natural radioactive isotope 4~K, 0.0118% of isotopes forming K element, with half life 1.28 ~ l09, in the time range of planet age and elements origin. So, one easy way to assess both the importance and evaluation of radioactive contamination at global scale should be to establish a RCF （radioactive contamination factor） as a percentage of 137Cs contaminant radioactivity in marine sediments, compared to 4~K natural radioactivity present from the very beginning of earth, both expressed as Bq per gram of sediment. In the frame of these rather general considerations, a research project has started in Mexico whose varied purposes are： to characterize sea regions in both vast littorals in the country, by its natural 4~K radioactivity present in sea salts, as well as to determine if 137Cs traces produced by recent radioactive contamination have reached their coasts. Also, to assess the 137Cs traces already present in marine sediments as a result of more than two thousand nuclear test explosions performed till now, rather than contamination produced by four main accidents in nuclear reactors during the last 60 years. It is proposed a radioactive contamination factor obtained from samples taken up in both coasts during the last two years, which should be very useful in two ways： first to assess the real danger of radioactive contamination already present by comparing with natural radioactivity, and second to assess the growth, equilibrium or drop of radioactive contamination, given that nuclear energy is still the best option to solve the large energy demand foreseen in the near future.展开更多
The contradiction would produce the power only in the condition that this contradiction stays within a substance. The movement power for the cognition is not produced by the contradiction between people＇s thinking an...The contradiction would produce the power only in the condition that this contradiction stays within a substance. The movement power for the cognition is not produced by the contradiction between people＇s thinking and the objective things, for the thinking and the objective things are not in a same substance, which is Hegel＇s problem. Then, where is the power for people＇s cognition from？ This paper has a conclusion as this： The ＂Ego＂ and the ＂Nonego＂ are a pair of contradiction within a person＇s body. The cognition is a kind of people＇s movement. So, the cognition is the process moved by the power from the ＂Ego＂ and the ＂Nonego＂ of a person＇s body.展开更多
Chronosequences of ancient rice terraces serve as an invaluable archive for reconstructions of historical human-environment interactions. Presently, however, these reconstructions are based on traditional soil physico...Chronosequences of ancient rice terraces serve as an invaluable archive for reconstructions of historical human-environment interactions. Presently, however, these reconstructions are based on traditional soil physico-chemical properties. The microorganisms in palaeosols have been unexplored. We hypothesized that microbial information can be used as an additional proxy to complement and consolidate archaeological interpretations. To test this hypothesis, the palaeoenvironmental methanogenic archaeal DNA in Longji Terraces, one of the famous ancient terraces in China, dating back to the late Yuan Dynasty(CE1361–1406), was chronosequenced by high-throughput sequencing. It was found that the methanogenic archaeal abundance, diversity and community composition were closely associated with the 630 years of rice cultivation and in line with changes in multi-proxy data. Particularly, the centennial-and decadalscale influences of known historical events, including social turbulences(The Taiping Rebellion, CE1850–1865), palaeoclimate changes(the Little Ice Age) and recorded natural disasters(earthquakes and inundation), on ancient agricultural society were clearly echoed in the microbial archives as variations in alpha and beta diversity. This striking correlation suggests that the microorganisms archived in palaeosols can be quantitatively and qualitatively analyzed to provide an additional proxy, and palaeo-microbial information could be routinely incorporated in the toolkit for archaeological interpretation.展开更多
Background:Although intrinsic risk factors contributing to esophageal food impaction are well established,whether social behavior affects its occurrence has not yet been examined.Methods:We conducted a retrospective r...Background:Although intrinsic risk factors contributing to esophageal food impaction are well established,whether social behavior affects its occurrence has not yet been examined.Methods:We conducted a retrospective review of the gastroenterology endoscopy procedural documentation software for the period of 2001–2012 to identify all patients who presented to our emergency department for esophageal foreign-body removal at the time of national athletic events and holidays associated with dietary indiscretions.Results:We found that adults undergoing emergent esophagogastroduodenoscopy during periods celebrating cultural holidays and national athletic events were more likely to experience esophageal food impaction compared with those undergoing emergent endoscopy during periods not associated with these events(36.8% vs 3.6%;P<0.001):a 10-fold increase.During a national holiday/athletic event period,the most common impacted food item was turkey(50%)followed by chicken(29%)and beef(21%).Conclusions:Esophageal food impaction is more likely to occur on American holidays and national athletic events and is associated with large meals.Patients with intrinsic risk factors should be advised to modify their diet during cultural events associated with tachyphagia and large meals to prevent esophageal food impaction.展开更多
基金funded by the Chinese Academy of Sciences (Grant No. XDA05050404)the Natural Science Foundation of China (Grant Nos. 31000233, 31170432)International Center for Integrated Mountain Development (Grant No. HICAP)
文摘Extreme weather events have played an important role in driving the ecosystem dynamics in high altitude areas, but the underlying mechanism remains unclear. To understand if and how the soil processes of an ecosystem react to extreme drought, we manipulated a once-in-a-century meteorological extreme drought in an alpine meadow on the Tibetan Plateau, which is also known as the ＂forerunner of global weather changes＂. The extremity was determined by statistical extreme weather events with respect to a historical reference period from April to September during 1962 - 2004, where the local historical precipitation data was calculated and intensified to loo-year recurrent drought event with Gumbel I distribution. The indicators we measured included soil microbial biomass C/N/P and soil enzymatic activities of phosphatase （AP） disbounding organic phosphate, cellobiohydrolase （CBH）, β- glucocidase （BG）, N-releasing enzyme N-acetyl- glucosaminidase （NAG） as well as soil respirations, during and after the treatments. It was found that the manipulated event induced a rapid shift in microbial biomass and activities, indicating a lower resistance of the underground process. However, the microbial and biochemical parameters saw rapid recovery after the event, which meant the soil processes enjoyed high resilience. The high responsiveness and lag-time effects of the soil indicators rendered new horizons for us to evaluate the interaction between the extremes and the ecosystem stability. Our study indicated that the once-in-a-century extreme drought induced very short term response in the soil biotic process, and the soil processes worked to buffer against such events under the observation period.
文摘During the course of a hypothetical severe accident in a nuclear Pressurized Water Reactor （PWR）, containment reactor is pressurized by steam and hydrogen released from a primary circuit breach and distributed into the containment according to convective flows and steam wall condensation. In addition, core degradation leads to fission products released into the containment. Water spraying is used in the containment as mitigation means in order to reduce pressure, to remove fission products and to enhance the gas mixing in case of presence of hydrogen. This paper presents results of the TOSQAN aerosol program undertaken by the Institute de Radioprotection et de Sfiret6 Nucl6aire （IRSN） devoted to study the aerosol removal by a spray, for typical accidental thermal hydraulic conditions in PWR containment. The TOSQAN facility is a large enclosure devoted to simulate typical accidental thermal hydraulic flow conditions in nuclear PWR containment.
文摘As a result of more than two thousand nuclear tests performed since 1945, two war actions and few accidents in nuclear reactor, it does already exist a radioactive contamination at global scale. This contamination has been accumulated mainly in marine sediments, because sea is about 80% of planet surface, and solid fission products released by nuclear explosions are transported by wind first and then by rain to liquid and solid portions on earth, while gaseous fission products are diffused in the atmosphere. In this way, heavy, high yielding fission products, such as 137Cs, get marine sediments, where they are found mixed with heavy radioactive natural elements such as U, Th and their also radioactive decay products. But since alkaline are so abundant on earth, it is also found natural radioactive isotope 4~K, 0.0118% of isotopes forming K element, with half life 1.28 ~ l09, in the time range of planet age and elements origin. So, one easy way to assess both the importance and evaluation of radioactive contamination at global scale should be to establish a RCF （radioactive contamination factor） as a percentage of 137Cs contaminant radioactivity in marine sediments, compared to 4~K natural radioactivity present from the very beginning of earth, both expressed as Bq per gram of sediment. In the frame of these rather general considerations, a research project has started in Mexico whose varied purposes are： to characterize sea regions in both vast littorals in the country, by its natural 4~K radioactivity present in sea salts, as well as to determine if 137Cs traces produced by recent radioactive contamination have reached their coasts. Also, to assess the 137Cs traces already present in marine sediments as a result of more than two thousand nuclear test explosions performed till now, rather than contamination produced by four main accidents in nuclear reactors during the last 60 years. It is proposed a radioactive contamination factor obtained from samples taken up in both coasts during the last two years, which should be very useful in two ways： first to assess the real danger of radioactive contamination already present by comparing with natural radioactivity, and second to assess the growth, equilibrium or drop of radioactive contamination, given that nuclear energy is still the best option to solve the large energy demand foreseen in the near future.
文摘The contradiction would produce the power only in the condition that this contradiction stays within a substance. The movement power for the cognition is not produced by the contradiction between people＇s thinking and the objective things, for the thinking and the objective things are not in a same substance, which is Hegel＇s problem. Then, where is the power for people＇s cognition from？ This paper has a conclusion as this： The ＂Ego＂ and the ＂Nonego＂ are a pair of contradiction within a person＇s body. The cognition is a kind of people＇s movement. So, the cognition is the process moved by the power from the ＂Ego＂ and the ＂Nonego＂ of a person＇s body.
基金supported by National Natural Science Foundation of China(41671267,41430859 and 41271256)the CAS Strategic Priority Research Program Grant(XDB15020103)+2 种基金National Key R&D Program(2016YFD0200306)National Basic Research Program(973 Program)(2014CB954500)Knowledge Innovation Program of Chinese Academy of Sciences(ISSASIP1639)
文摘Chronosequences of ancient rice terraces serve as an invaluable archive for reconstructions of historical human-environment interactions. Presently, however, these reconstructions are based on traditional soil physico-chemical properties. The microorganisms in palaeosols have been unexplored. We hypothesized that microbial information can be used as an additional proxy to complement and consolidate archaeological interpretations. To test this hypothesis, the palaeoenvironmental methanogenic archaeal DNA in Longji Terraces, one of the famous ancient terraces in China, dating back to the late Yuan Dynasty(CE1361–1406), was chronosequenced by high-throughput sequencing. It was found that the methanogenic archaeal abundance, diversity and community composition were closely associated with the 630 years of rice cultivation and in line with changes in multi-proxy data. Particularly, the centennial-and decadalscale influences of known historical events, including social turbulences(The Taiping Rebellion, CE1850–1865), palaeoclimate changes(the Little Ice Age) and recorded natural disasters(earthquakes and inundation), on ancient agricultural society were clearly echoed in the microbial archives as variations in alpha and beta diversity. This striking correlation suggests that the microorganisms archived in palaeosols can be quantitatively and qualitatively analyzed to provide an additional proxy, and palaeo-microbial information could be routinely incorporated in the toolkit for archaeological interpretation.
文摘Background:Although intrinsic risk factors contributing to esophageal food impaction are well established,whether social behavior affects its occurrence has not yet been examined.Methods:We conducted a retrospective review of the gastroenterology endoscopy procedural documentation software for the period of 2001–2012 to identify all patients who presented to our emergency department for esophageal foreign-body removal at the time of national athletic events and holidays associated with dietary indiscretions.Results:We found that adults undergoing emergent esophagogastroduodenoscopy during periods celebrating cultural holidays and national athletic events were more likely to experience esophageal food impaction compared with those undergoing emergent endoscopy during periods not associated with these events(36.8% vs 3.6%;P<0.001):a 10-fold increase.During a national holiday/athletic event period,the most common impacted food item was turkey(50%)followed by chicken(29%)and beef(21%).Conclusions:Esophageal food impaction is more likely to occur on American holidays and national athletic events and is associated with large meals.Patients with intrinsic risk factors should be advised to modify their diet during cultural events associated with tachyphagia and large meals to prevent esophageal food impaction.
