Since the end of 2019,the world has suffered from a pandemic of the disease called COVID-19.WHO reports show approximately 113M confirmed cases of infection and 2.5 M deaths.All nations are affected by this nightmare ...Since the end of 2019,the world has suffered from a pandemic of the disease called COVID-19.WHO reports show approximately 113M confirmed cases of infection and 2.5 M deaths.All nations are affected by this nightmare that continues to spread.Widespread fear of this pandemic arose not only from the speed of its transmission:a rapidly changing“normal life”became a fear for everyone.Studies have mainly focused on the spread of the virus,which showed a relative decrease in high temperature,low humidity,and other environmental conditions.Therefore,this study targets the effect of weather in considering the spread of the novel coronavirus SARS-CoV-2 for some confirmed cases in Iraq.The eigenspace decomposition technique was used to analyze the effect of weather conditions on the spread of the disease.Our theoretical findings showed that the average number of confirmed COVID-19 cases has cyclic trends related to temperature,humidity,wind speed,and pressure.We supposed that the dynamic spread of COVID-19 exists at a temperature of 130 F.The minimum transmission is at 120 F,while steady behavior occurs at 160 F.On the other hand,during the spread of COVID-19,an increase in the rate of infection was seen at 125%humidity,where the minimum spread was achieved at 200%.Furthermore,wind speed showed the most significant effect on the spread of the virus.The spread decreases with a wind speed of 45 KPH,while an increase in the infectious spread appears at 50 KPH.展开更多
[Objective] The paper aims to study the effect of weather on rice production in Guangxi. [Method] The authors evaluated the effect of weather and weather disasters in Guangxi on rice production by comparison and analy...[Objective] The paper aims to study the effect of weather on rice production in Guangxi. [Method] The authors evaluated the effect of weather and weather disasters in Guangxi on rice production by comparison and analysis in terms of temperature,rain and sunlight in 2009. [Result] The study summarized the main favorable and unfavorable weather conditions of rice growth,and proposed the measures and suggestions to tend to interest and avoid harm on rice production in Guangxi. [Conclusion] This study provides references to the evaluations about effect of weather in Guangxi on rice production and suggestions on how to reduce weather disasters influence and ensure rice production security.展开更多
1 Introduction Global climate change is one of the greatest challenges facing humankind in the 21st century.Studying,and utilising,the carbon sink caused by the weathering of silicate minerals has been a key research ...1 Introduction Global climate change is one of the greatest challenges facing humankind in the 21st century.Studying,and utilising,the carbon sink caused by the weathering of silicate minerals has been a key research focus for展开更多
We investigated the weathering-pedogenesis of carbonate rocks and its environmental effects in subtropical regions of China. The investigation demonstrated that the weathering- pedogenesis of carbonate rocks is the pr...We investigated the weathering-pedogenesis of carbonate rocks and its environmental effects in subtropical regions of China. The investigation demonstrated that the weathering- pedogenesis of carbonate rocks is the process of a joint action of corrosion and illuviation and metasomatism in subtropical region. It is characterized by multi-stage, multi-path and multi-style. With the persisting development of weathering-pedogenesis of carbonate rocks, metasomatic pedogenesis progressively became the main process of the weathering-pedogenesis and the dominant style of formation of minerals. And it proceeds through the whole process of evolution of the weathering-pedogenesis of carbonate rocks. The stage evolution of weathering-pedogenesis of carbonate rocks and the fractionation evolution of newly produced minerals are characterized by obvious vertically zoning structures and the rules of gradation of elements geochemical characteristics in the carbonate rocks weathering profiles. The geochemical process of weathering-pedogenesis of carbonate rocks can be divided into three geochemical evolution stages, i.e., the Ca, Mg-depletion and Si, Al-enrichment stage; the Fe, Mn enrichment stage and the Si-depletion and Al-enrichment stage in the subtropical regions. Consistent with the three geochemical evolution stages, the sequence of formation and evolution of minerals can be divided into the clay mineral stage; the Fe, Mn oxide and the gibbsite stage. The influence of weathering-pedogenesis of carbonate rocks on the chemical forms of heavy elements is mainly affected via newly produced components and minerals in the process of weathering-pedogenesis, e.g., iron oxide minerals and organic matters. The important mechanism for the mobilization, transport and pollution of F and As is affected the selective adsorption and desorption of F and As on the surface of iron oxide minerals in the subtropical karst zones, i.e., the selective adsorption and desorption on mineral surfaces of newly produced minerals in the process of weathering-pedogenesis control the geochemical behavior of elements on the Earth＇s surface and environmental quality in subtropical regions.展开更多
China has accumulated massive fine grained copper mine tailings stocks because of the past mining activities in this area. The tailings contain a variety of heavy metals, and the mass percent of Cu, which is one of th...China has accumulated massive fine grained copper mine tailings stocks because of the past mining activities in this area. The tailings contain a variety of heavy metals, and the mass percent of Cu, which is one of the main contaminants in tailings, is up to 0.2601% (analysis by XRF). The Cu can pollute soil and groundwater by rain leaching in the form of Cu(Ⅱ), furthermore ,the fine grained copper-ore-tailings can contaminant larger area by wind for its small granularity ( < 74 μm). The main cause of weathering of mine tailings is due to oxidative dissolution of sulfides. Microorganisms, such as Acidithiobacillus ferrooxidans, play an important role in weathering. These bacteria attach to exposed to mineral surfaces by excreting extracellular polymers and oxidize the sulfide mineral. Some of these bacteria also oxidize Fe2+ to Fe3+ which can chemically oxidize sulfide minerals. These reactions produce voluminous quantities of acid mine drainage and heavy metals which are harmful to the environment and human healthy. This study aims at finding the weathering effects of A. ferrooxidans to Cu(II) pollution of fine grained copper mine tailings, and our experiment applied indigenous A. ferrooxidans FJ-01 to leach the tailings. The optimum test parameters were obtained using shaking flask experiment and SEM observation under the following experimental conditions: 39 days residence time, pulp density 1%-15% (1%, 5% and 15%), 30℃, 120 rpm, pH between 1-3 and redox potential between 400-650 mV. The test results show that the leaching rate of Cu reached 43.1% when the pulp density was 1% after 33 days and kept invariant till the end of the test. In addition, the leaching rate of Cu will decrease as the increase of pulp density, and the maximum rate of 15% pulp density was only 12.5%. From the SEM, it can be seen that the fine grain of tailings flocculated to conglobation under the action of bacterial leaching.展开更多
Air pollution has ever become a global major public health problem.Previous studies showed that air pollution is associated with excessive mortality and morbidity of respiratory disease[1-2].The extreme weather temper...Air pollution has ever become a global major public health problem.Previous studies showed that air pollution is associated with excessive mortality and morbidity of respiratory disease[1-2].The extreme weather temperature can impact human health and the thermal stresses can lead not only to direct deaths and illnesses,but also to aggravation of respiratory disease[3-4].Though the independent展开更多
文摘Since the end of 2019,the world has suffered from a pandemic of the disease called COVID-19.WHO reports show approximately 113M confirmed cases of infection and 2.5 M deaths.All nations are affected by this nightmare that continues to spread.Widespread fear of this pandemic arose not only from the speed of its transmission:a rapidly changing“normal life”became a fear for everyone.Studies have mainly focused on the spread of the virus,which showed a relative decrease in high temperature,low humidity,and other environmental conditions.Therefore,this study targets the effect of weather in considering the spread of the novel coronavirus SARS-CoV-2 for some confirmed cases in Iraq.The eigenspace decomposition technique was used to analyze the effect of weather conditions on the spread of the disease.Our theoretical findings showed that the average number of confirmed COVID-19 cases has cyclic trends related to temperature,humidity,wind speed,and pressure.We supposed that the dynamic spread of COVID-19 exists at a temperature of 130 F.The minimum transmission is at 120 F,while steady behavior occurs at 160 F.On the other hand,during the spread of COVID-19,an increase in the rate of infection was seen at 125%humidity,where the minimum spread was achieved at 200%.Furthermore,wind speed showed the most significant effect on the spread of the virus.The spread decreases with a wind speed of 45 KPH,while an increase in the infectious spread appears at 50 KPH.
基金Supported by Guangxi Natural Fund Project (0832204 )Guangxi Agricultural Key Technological Project (200702)~~
文摘[Objective] The paper aims to study the effect of weather on rice production in Guangxi. [Method] The authors evaluated the effect of weather and weather disasters in Guangxi on rice production by comparison and analysis in terms of temperature,rain and sunlight in 2009. [Result] The study summarized the main favorable and unfavorable weather conditions of rice growth,and proposed the measures and suggestions to tend to interest and avoid harm on rice production in Guangxi. [Conclusion] This study provides references to the evaluations about effect of weather in Guangxi on rice production and suggestions on how to reduce weather disasters influence and ensure rice production security.
基金supported by the National Natural Science Foundation of China (Grant Nos. 41373078 41173091)the National Key Basic Research Programme of China (Grant No. 2013CB956702)
文摘1 Introduction Global climate change is one of the greatest challenges facing humankind in the 21st century.Studying,and utilising,the carbon sink caused by the weathering of silicate minerals has been a key research focus for
基金the Ministry of Science and Technology of China（Grant No.2006CB403200）National Natural Science Foundation of China（Grant No.49463011,49833002 and 49962002）+2 种基金the open foundation projects of the State Key Laboratory of Environmental Geochemistry（in the years of 1993 and 1995）Engineering Project for Cross-century Qualified Scientific and Technological Personnel of Guizhou Province （2000-2004）Science Foundation of Guizhou Province.
文摘We investigated the weathering-pedogenesis of carbonate rocks and its environmental effects in subtropical regions of China. The investigation demonstrated that the weathering- pedogenesis of carbonate rocks is the process of a joint action of corrosion and illuviation and metasomatism in subtropical region. It is characterized by multi-stage, multi-path and multi-style. With the persisting development of weathering-pedogenesis of carbonate rocks, metasomatic pedogenesis progressively became the main process of the weathering-pedogenesis and the dominant style of formation of minerals. And it proceeds through the whole process of evolution of the weathering-pedogenesis of carbonate rocks. The stage evolution of weathering-pedogenesis of carbonate rocks and the fractionation evolution of newly produced minerals are characterized by obvious vertically zoning structures and the rules of gradation of elements geochemical characteristics in the carbonate rocks weathering profiles. The geochemical process of weathering-pedogenesis of carbonate rocks can be divided into three geochemical evolution stages, i.e., the Ca, Mg-depletion and Si, Al-enrichment stage; the Fe, Mn enrichment stage and the Si-depletion and Al-enrichment stage in the subtropical regions. Consistent with the three geochemical evolution stages, the sequence of formation and evolution of minerals can be divided into the clay mineral stage; the Fe, Mn oxide and the gibbsite stage. The influence of weathering-pedogenesis of carbonate rocks on the chemical forms of heavy elements is mainly affected via newly produced components and minerals in the process of weathering-pedogenesis, e.g., iron oxide minerals and organic matters. The important mechanism for the mobilization, transport and pollution of F and As is affected the selective adsorption and desorption of F and As on the surface of iron oxide minerals in the subtropical karst zones, i.e., the selective adsorption and desorption on mineral surfaces of newly produced minerals in the process of weathering-pedogenesis control the geochemical behavior of elements on the Earth＇s surface and environmental quality in subtropical regions.
文摘China has accumulated massive fine grained copper mine tailings stocks because of the past mining activities in this area. The tailings contain a variety of heavy metals, and the mass percent of Cu, which is one of the main contaminants in tailings, is up to 0.2601% (analysis by XRF). The Cu can pollute soil and groundwater by rain leaching in the form of Cu(Ⅱ), furthermore ,the fine grained copper-ore-tailings can contaminant larger area by wind for its small granularity ( < 74 μm). The main cause of weathering of mine tailings is due to oxidative dissolution of sulfides. Microorganisms, such as Acidithiobacillus ferrooxidans, play an important role in weathering. These bacteria attach to exposed to mineral surfaces by excreting extracellular polymers and oxidize the sulfide mineral. Some of these bacteria also oxidize Fe2+ to Fe3+ which can chemically oxidize sulfide minerals. These reactions produce voluminous quantities of acid mine drainage and heavy metals which are harmful to the environment and human healthy. This study aims at finding the weathering effects of A. ferrooxidans to Cu(II) pollution of fine grained copper mine tailings, and our experiment applied indigenous A. ferrooxidans FJ-01 to leach the tailings. The optimum test parameters were obtained using shaking flask experiment and SEM observation under the following experimental conditions: 39 days residence time, pulp density 1%-15% (1%, 5% and 15%), 30℃, 120 rpm, pH between 1-3 and redox potential between 400-650 mV. The test results show that the leaching rate of Cu reached 43.1% when the pulp density was 1% after 33 days and kept invariant till the end of the test. In addition, the leaching rate of Cu will decrease as the increase of pulp density, and the maximum rate of 15% pulp density was only 12.5%. From the SEM, it can be seen that the fine grain of tailings flocculated to conglobation under the action of bacterial leaching.
基金supported by the Gong-Yi Program of China Meteorological Administration(GYHY201106034)National Natural Science Foundation of China(41075103)
文摘Air pollution has ever become a global major public health problem.Previous studies showed that air pollution is associated with excessive mortality and morbidity of respiratory disease[1-2].The extreme weather temperature can impact human health and the thermal stresses can lead not only to direct deaths and illnesses,but also to aggravation of respiratory disease[3-4].Though the independent
