After two weeks of discussions and consultations at the 28 th Conference of the Parties to the United Nations Framework Convention on Climate Change(COP28),states parties finally reached a series of important sustaina...After two weeks of discussions and consultations at the 28 th Conference of the Parties to the United Nations Framework Convention on Climate Change(COP28),states parties finally reached a series of important sustainable development resolutions and voluntary initiatives.In this paper,the possible impact of these resolutions on Taiwan was mainly discussed,and the relevant regulations and policies that the Taiwan government may enact were analyzed.展开更多
As the global elderly population increases,depression within this group has become a significant public health concern.Although exercise has been recognized for its potential to improve depression in the elderly,the b...As the global elderly population increases,depression within this group has become a significant public health concern.Although exercise has been recognized for its potential to improve depression in the elderly,the benefits,risks,and implementation strategies remain contentious.This review attempts to examine the impact of exercise on depression in older adults,including potential benefits,risks,and suggestions for application.Our analysis highlights the benefits of aerobic and resistance training,which can significantly alleviate depressive symptoms and enhance overall quality of life.Despite these benefits,the review acknowledges the complexity of the exercise-depression interaction in the elderly,necessitating personalized exercise regimens.Potential risks,such as muscle and joint pain,are pointed out,emphasizing the importance of tailored,supervised exercise programs.The review calls for future research to focus on identifying the most effective types of exercise and regimens for this population,considering factors such as age,gender,and existing health conditions.Lastly,it advocates for the inclusion of exercise in comprehensive treatment plans for depression in older adults,viewing it as a promising step toward achieving holistic mental health care in a growing demographic.展开更多
The word “senescence” comes from the Latin senescens, meaning “to begin to age”, and is characterized by a long-lasting but reversible block in proliferation, resulting from stress-induced cell cycle arrest of pre...The word “senescence” comes from the Latin senescens, meaning “to begin to age”, and is characterized by a long-lasting but reversible block in proliferation, resulting from stress-induced cell cycle arrest of previously replication-competent cells.展开更多
Based on the meteorological data from 33 stations of Three Gorges Reservoir from 1960 to 2008,climate yield of rice,corn and winter wheat and the changes of climatic potential productivity after water storage in Three...Based on the meteorological data from 33 stations of Three Gorges Reservoir from 1960 to 2008,climate yield of rice,corn and winter wheat and the changes of climatic potential productivity after water storage in Three Gorges Reservoir were calculated by the dynamic statistic model of crop growth.The results showed that the temperature in Three Gorges Reservoir was fluctuant decreased before late 1980s,and warmed rapidly after the late 1980s.The precipitation had little change before the late 1990s and had a slight decrease after the late 1990s.Sunshine hours were more in 1960s and 1970s,and then it changed little after 1980s.After water storage,the temperature increased in Three Gorges Reservoir as a whole.The precipitation decreased in the south of Three Gorges Reservoir,while it increased in the northwest of Three Gorges Reservoir.The sunshine hours were reduced except that in the vicinity of Dianjiang.After water storage,climatic potential productivity of rice decreased in the northwest and the northeast,while it increased in the south of Three Gorges Reservoir.The climatic potential productivity of corn decreased in the northeast and the southwest,but increased in the rest of Three Gorges Reservoir.The climatic potential productivity of winter wheat increased almost in total.展开更多
[Objective] The paper was to study the dynamic changes of nitrogen in saline-alkaline paddy field and its potential environment impacts. [Method] With typical sodic saline-alkaline paddy fields of Songnen Plain as stu...[Objective] The paper was to study the dynamic changes of nitrogen in saline-alkaline paddy field and its potential environment impacts. [Method] With typical sodic saline-alkaline paddy fields of Songnen Plain as study object,field test method was used to explore the dynamic changes was strong alkof nitrogen in paddy field of the region and its potential impact on environment. [Result] The soil in test regionaline with high CEC and C/N ratios,as well as poor preserving capacity of fertilizer. During the two-year field experiment,the indicators of salinization fluctuated. Initially,the concentrations of total nitrogen and ammonia nitrogen reached their maximum values,then decreased over time as a result of heavy rain. The maximum of nitrate concentration appeared later than those of total nitrogen and ammonia nitrogen. Ammonia volatilization accounted for 18.9%-28.8% of the nitrogen loss. The total nitrogen concentration in surface water was higher than the national Class Ⅲ surface water environmental quality standard. The concentration of ammonia from the recession flow of agricultural field was considerably high,which would potentially threaten the fishery in the downstream of Chagan Lake. [Conclusion] The study provided theoretical basis for saline-alkaline soil management and conservation of water and fishery resources.展开更多
The impacts of cloud-induced mass forcing on the development of the moist potential vorticity (MPV) anomaly associated with torrential rains are investigated by using NCEP/NCAR 1? × 1? data. The MPV ten...The impacts of cloud-induced mass forcing on the development of the moist potential vorticity (MPV) anomaly associated with torrential rains are investigated by using NCEP/NCAR 1? × 1? data. The MPV tendency equation with the cloud-induced mass forcing is derived, and applied to the torrential rain event over the Changjiang River-Huaihe River Valleys during 26–30 June 1999. The result shows that positive anomalies are located mainly between 850 hPa and 500 hPa, while the maximum MPV, maximum positive tendency of the MPV, and maximum surface rainfall are nearly collocated. The cloud-induced mass forcing contributes to the positive tendency of the moist potential vorticity anomaly. The results indicate that the MPV may be used to track the propagation of rain systems for operational applications.展开更多
The productivity exploitation degree,suitable exploitation degree and exploitable exploitation degree of production potential of winter wheat in three climate zones of Tianshui were calculated.The impacts of climate c...The productivity exploitation degree,suitable exploitation degree and exploitable exploitation degree of production potential of winter wheat in three climate zones of Tianshui were calculated.The impacts of climate changes on it were analyzed.The results showed the exploitation degree of production potential of winter wheat was still low in the north of Wei River,the valley of Wei River and the area of Guan Mountain in Tianshui,being 49.9%-60.0%.Both the suitable exploitation degree and exploitable exploitation degree of production potential of winter wheat were comparatively high,being 73.6%-78.7% and 18.7%-23.8% respectively.The sequencing was the north of Wei River>the valley of Wei River>the area of Guan Mountain.In the long run,it was of great potential to be excavated.The average temperature,sunshine hours for growth season of winter wheat had negative effects on exploitation degree,suitable exploitation degree and exploitable degree of production potential of winter wheat.The precipitation had the positive effect.And the temperature in the entire growth period,temperature in autumn,the sunshine in winter had remarkable negative effects on the exploitation degree of the production potential in Tianshui and the north of Wei River.The precipitation in the entire growth period,the precipitation in autumn had remarkable positive effects in Tianshui and each climate zones.And some moderate development countermeasures of regional production potential were proposed.展开更多
Evaporation, which is an important factor in the water balance at the basin scale, is a critical variable in the determination of local available water resources. Since the potential evaporation is mainly influenced b...Evaporation, which is an important factor in the water balance at the basin scale, is a critical variable in the determination of local available water resources. Since the potential evaporation is mainly influenced by meteorological variables, it is necessary to investigate the extent to which different meteorological variables affect the potential evaporation. The aim of this study was to explore the variation trends of different meteorological variables, and their impacts on the potential evaporation. This study selected the Hailar Meteorological Station of the Hailar region, which is situated in a cold, semi-arid, and sub-humid region, as a case study site. Based on observed daily meteorological data from 1951 to 2009, the potential evaporation was calculated with the Penman formula, and the variations of meteorological variables were investigated with the nonparametric Mann-Kendall test. The correlation between the potential evaporation and each meteorological variable at annual and seasonal scales was also analyzed. The results show that the annual and seasonal potential evaporation and air temperature present increasing trends, whereas the wind speed, sunshine duration, and relative humidity present decreasing trends. Among the meteorological variables, the air temperature and relative humidity are the key factors that affect potential evaporation at different time scales, and the impacts of other meteorological variables on the potential evaporation are not significant and vary with time scales.展开更多
An effective parameter in the miscible-CO_2 enhanced oil recovery procedure is the minimum miscibility pressure(MMP)defined as the lowest pressure that the oil in place and the injected gas into reservoir achieve misc...An effective parameter in the miscible-CO_2 enhanced oil recovery procedure is the minimum miscibility pressure(MMP)defined as the lowest pressure that the oil in place and the injected gas into reservoir achieve miscibility at a given temperature. Flue gases released from power plants can provide an available source of CO_2,which would otherwise be emitted to the atmosphere, for injection into a reservoir. However, the costs related to gas extraction from flue gases is potentially high. Hence, greater understanding the role of impurities in miscibility characteristics between CO_2 and reservoir fluids helps to establish which impurities are tolerable and which are not. In this study, we simulate the effects of the impurities nitrogen(N_2), methane(C_1), ethane(C_2) and propane(C_3) on CO_2 MMP. The simulation results reveal that,as an impurity, nitrogen increases CO_2–oil MMP more so than methane. On the other hand, increasing the propane(C_3)content can lead to a significant decrease in CO_2 MMP, whereas varying the concentrations of ethane(C_2) does not have a significant effect on the minimum miscibility pressure of reservoir crude oil and CO_2 gas. The novel relationships established are particularly valuable in circumstances where MMP experimental data are not available.展开更多
The sea area east of Chenshan Cape has peak tidal current flows that exceed 2.3 m s^-1,which make it a promising site for the development of tidal current energy.Before these resources can be exploited,a comprehensive...The sea area east of Chenshan Cape has peak tidal current flows that exceed 2.3 m s^-1,which make it a promising site for the development of tidal current energy.Before these resources can be exploited,a comprehensive assessment is needed of the potential environmental impacts of the extraction of this energy.In this paper,we describe our construction of a three-dimensional hydrodynamic model of the waters near Chengshan Cape,and verify the performance of the model using continuous data measured in situ.We modeled the potential impacts of the exploitation of these resources on the flow field by adding a momentum loss term in the governing equation of the model.Simulation results show that an assumed tidal farm with an estimated power output of 20.34 MW would have a significant impact on the surrounding water level,especially next to the farm,where fluctuation could reach 6 cm.The maximum drop in the flow velocity in the wake of the farm was predicted to be more than 0.8 m s^-1,and this influence would extend 10 km downstream.展开更多
Madagascar,a globally renowned biodiversity hotspot characterized by high rates of endemism,is one of the few remaining refugia for many plants and animal species.However,global climate change has greatly affected the...Madagascar,a globally renowned biodiversity hotspot characterized by high rates of endemism,is one of the few remaining refugia for many plants and animal species.However,global climate change has greatly affected the natural ecosystem and endemic species living in Madagascar,and will likely continue to influence species distribution in the future.Madagascar is home to six endemic baobab(Adansonia spp.,Bombacoideae[Malvaceae])species(Adansonia grandidieri,A.suarezensis,A.madagascariensis,A.perrieri,A.rubrostipa,A.za),which are remarkable and endangered plants.This study aimed to model the current distribution of suitable habitat for each baobab species endemic to Madagascar and determine the effect that climate change will have on suitable baobab habitat by the years 2050 and 2070.The distribution was modeled using MaxEnt based on locality information of 245 occurrence sites of six species from both online database and our own field work.A total of seven climatic variables were used for the modeling process.The present distribution of all six Madagascar's baobabs was largely influenced by temperature-related factors.Although both expansion and contraction of suitable habitat are predicted for all species,loss of original suitable habitat is predicted to be extensive.For the most widespread Madagascar baobab,A.za,more than 40%of its original habitat is predicted to be lost because of climate change.Based on these findings,we recommend that areas predicted to contract in response to climate change should be designated key protection regions for baobab conservation.展开更多
Climate change has affected and will continue to affect the spatial distribution patterns of marine organisms.To understand the impact of climate change on the distribution patterns and species richness of the Sciaeni...Climate change has affected and will continue to affect the spatial distribution patterns of marine organisms.To understand the impact of climate change on the distribution patterns and species richness of the Sciaenidae in China’s coastal waters,the maximum entropy model was used to combine six environmental factors and predict the potential distribution of 12 major species of Sciaenidae by 2050s under Representative Concentration Pathways(RCPs)2.6 and 8.5.The results showed that the average area under the receiver operating characteristic curve of the model was 0.917,indicating that the model predictions were accurate and reliable.The main driving factors affecting the potential distribution of these fishes were dissolved oxygen,salinity,and sea surface temperature(SST).There was an overall northward shift in the potential habitat areas of these fishes under the two climate scenarios.The total potential habitat areas of Larimichthys polyactis,Pennahia argentata,and Pennahia pawak decreased under both climate scenarios,while the total habitat area of Johnius belengerii,Pennahia anea,Miichthys miiuy,Collichthys lucidus,and Collichthys niveatus increased,suggesting that these might be loser and winner species,respectively.The expansion rate,contraction rate,degree of centroid change,and species richness in the potential habitats were generally more significant under RCP8.5 than RCP2.6.The mean shift rates of the potential distribution were 41.50 km/(10 a) and 29.20 km/(10 a) under RCP8.5 and RCP2.6,respectively.The changes in Sciaenidae species richness under climate change were bounded by the Changjiang River Estuary waters,with obvious north-south differences.Some waters with increased species richness may become refuges for Sciaenidae fishes under climate change.The richness and habitat area change rate of some aquatic germplasm resources will decrease,meanings that these reserves are more sensitive to climate change,and more attention should be paid to the potential challenges and opportunities for fishery managers.This study may provide a scientific basis for the management and conservation of Sciaenidae in China under climate change.展开更多
BACKGROUND Oral potential malignant disorders(OPMDs)are a precancerous condition of oral disease.Several studies have found that betel quid chewing,smoking and alcohol drinking might be the risk factors of OPMDs.But t...BACKGROUND Oral potential malignant disorders(OPMDs)are a precancerous condition of oral disease.Several studies have found that betel quid chewing,smoking and alcohol drinking might be the risk factors of OPMDs.But the relationships of them,especially their interaction are still inconclusive.AIM To evaluate the relationship between betel quid chewing and OPMDs and to explore the interaction of smoking and alcohol drinking on the relationship.METHODS We searched Pub Med,Web of Science,Embase and the Cochrane Library databases with items complete until January 2021 for relevant studies.The research data were extracted according to the inclusion criteria.The pooled odds ratios(ORs)and 95%confidence intervals(CIs)were used to evaluate the effect size.Subgroup analysis was performed to assess interactions between exposures and OPMDs.Relative excess risk of interaction(RERI)was used to estimate the size of interaction.RESULTS Nine articles were selected in the final meta-analysis.The results showed that betel quid chewing(pooled OR:8.70,95%CI:5.18-14.61),alcohol consumption(pooled OR:1.95,95%CI:1.5-2.55),and smoking(pooled OR:4.35,95%CI:3.06-6.2)could significantly increase the risk of OPMDs compared to individuals without these behaviors.Smoking and alcohol drinking synergistically increased the association between betel quid chewing and OPMDs(pooled OR;:14.38,95%CI:7.14-28.95;pooled OR;:11.12,95%CI:8.00-15.45,respectively).The RERI;and RERI;were 2.33 and 1.47,respectively.CONCLUSION The synergistic effects between smoking/drinking and betel quid highlights the importance of focusing on individuals with multiple exposures.Further study should be conducted to confirm these interactions.展开更多
Wind energy has been rapidly developed in China during the past decades and the installed capacity has been the largest in the world. In the future, utilization of wind power is still expected to carry out in China ma...Wind energy has been rapidly developed in China during the past decades and the installed capacity has been the largest in the world. In the future, utilization of wind power is still expected to carry out in China mainly with a large-scale centralized layout. Here, we examine the potential climatic impacts of large-scale windfarms associated with deployment scale in China using numerical experiments, in which four deployment scenarios were designed. These four scenarios represented relatively small- (484 GW), medium- (2165 GW) and large-scale (3490 GW and 5412 GW) installed wind power capacities, respectively. Results showed that turbulent kinetic energy, wind velocity, and air temperature varied consistently within those windfarms with the largest changes in turbine hub heights. Moreover, the above relatively large- scale windfarms could induce regional wanning with a maximum of above 0.8 °C in North China. This regional warming may be linked to an anomalous circulation pattern with a negative pressure anomaly center in Northeast China and a positive pressure anomaly center in the middle and lower reaches of the Yangtze-Huaihe River Basin.展开更多
Climate warming is expected to influence forest growth,composition and distribution.However,accurately estimating and predicting forest biomass,potential productivity or forest growth is still a challenge for forest m...Climate warming is expected to influence forest growth,composition and distribution.However,accurately estimating and predicting forest biomass,potential productivity or forest growth is still a challenge for forest managers dealing with land-use at the stand to regional levels.In the present study,we predicted the potential productivity(PP)of forest under current and future climate scenarios(RCP2.6,RCP4.5,RCP6.0 and RCP8.5)in Jilin province,northeastern China by using Paterson’s Climate Vegetation and Productivity(CVP)index model.The PP was validated by comparing it with the mean and maximum net primary production calculated from light energy utilization(GLM_PEM).Our results indicated that using the CVP index model is partially valid for predicting the potential forest productivity in northeastern China.PP exhibited obvious spatial heterogeneity varying from 4.6 to 8.9 m3 ha-1 year-1 with an increasing tendency from northwest to southeast driven by the precipitation across the region.The number of vegetation-active months,precipitation and insolation coefficient were identified as the primary factors affecting PP,but no significant relationship was found for warmest temperature or temperature fluctuation.Under future climate scenarios,PP across the Jilin Province is expected to increase from 1.38%(RCP2.6 in 2050)to 15.30%(RCP8.5 in 2070),especially in the eastern Songnen Plain(SE)for the RCP8.5 scenarios.展开更多
The emissions of greenhouse gasses in Egypt are about 0.58% of the total emissions of the world in the year 2015, although Egypt is one of the countries most affected by the impacts of climate change. By assessment an...The emissions of greenhouse gasses in Egypt are about 0.58% of the total emissions of the world in the year 2015, although Egypt is one of the countries most affected by the impacts of climate change. By assessment and analysis of the expected economic impacts of climate change by the year 2030, the Egyptian cultivated area will be reduced to about 0.949 million acres, equal to about 8.22% of the Egyptian cultivated area compared with the case of no sinking part of the Delta land, thus reducing crop area in Egypt to about 1.406 million acres, approximately to about 6.25% of crop area compared with the case of no sinking part of the Delta land, in addition to surplus in the Egyptian balance water to about 2.48 billion m3. In this case value of the Egyptian agriculture production will decrease by about 6.19 billion dollars, equal to about 6.19% compared with presumably no sinking of the Delta land. In the case of sinking 15% of Delta lands, with the change of the productivity and water consumption of most crops, the result will be a reduction in the cultivated area to about 0.94 million acres. In addition to decreasing the Egyptian crop area to about 1.39 million acres, with a deficit in the Egyptian balance water to about 4.74 billion m3 compared to the case of no sinking part of the Delta land, the cultivated area will decrease to about 8.17%, and the crop area will decrease 6.18%. Also, the value of the Egyptian agriculture production will decrease by about 12.51%. While compared to sinking part of the Delta land to about 15% of the total Delta area without the other impacts of climate change, the cultivated area will increase by about 0.06%;the crop area will increase by about 0.08%;also, the value of the Egyptian agriculture production will decrease by about 5.57%.展开更多
Ecotourism has been suggested as the altemative for the conflicts between tourism development and nature conservation especially for the protected area, such as biosphere reserve. Based on investigation of tourism res...Ecotourism has been suggested as the altemative for the conflicts between tourism development and nature conservation especially for the protected area, such as biosphere reserve. Based on investigation of tourism resources of The Changbaishan Biosphere Reserve (CBR) and tourism impacts on environment, economy and society, the potential of ecotourism development is analyzed in and around CBR. The results showed that the conditions in the study area are suitable for development of ecotourism, which is an effective approach for sustainable development of CBR.展开更多
The effects of projectile/target impedance matching and projectile shape on energy,momentum transfer and projectile melting during collisions are investigated by numerical simulation.By comparing the computation resul...The effects of projectile/target impedance matching and projectile shape on energy,momentum transfer and projectile melting during collisions are investigated by numerical simulation.By comparing the computation results with the experimental results,the correctness of the calculation and the statistical method of momentum transfer coefficient is verified.Different shapes of aluminum,copper and heavy tungsten alloy projectiles striking aluminum,basalt,and pumice target for impacts up to 10 km/s are simulated.The influence mechanism of the shape of the projectile and projectile/target density on the momentum transfer was obtained.With an increase in projectile density and length-diameter ratio,the energy transfer time between the projectile and targets is prolonged.The projectile decelerates slowly,resulting in a larger cratering depth.The energy consumed by the projectile in the excavation stage increased,resulting in lower mass-velocity of ejecta and momentum transfer coefficient.The numerical simulation results demonstrated that for different projectile/target combinations,the higher the wave impedance of the projectile,the higher the initial phase transition velocity and the smaller the mass of phase transition.The results can provide theoretical guidance for kinetic impactor design and material selection.展开更多
文摘After two weeks of discussions and consultations at the 28 th Conference of the Parties to the United Nations Framework Convention on Climate Change(COP28),states parties finally reached a series of important sustainable development resolutions and voluntary initiatives.In this paper,the possible impact of these resolutions on Taiwan was mainly discussed,and the relevant regulations and policies that the Taiwan government may enact were analyzed.
基金the 2021 Undergraduate Education and Teaching Reform Project of Shandong Province“Research on the Model of Integrated Education Inside and Outside of College Physical Education”(M2021107).
文摘As the global elderly population increases,depression within this group has become a significant public health concern.Although exercise has been recognized for its potential to improve depression in the elderly,the benefits,risks,and implementation strategies remain contentious.This review attempts to examine the impact of exercise on depression in older adults,including potential benefits,risks,and suggestions for application.Our analysis highlights the benefits of aerobic and resistance training,which can significantly alleviate depressive symptoms and enhance overall quality of life.Despite these benefits,the review acknowledges the complexity of the exercise-depression interaction in the elderly,necessitating personalized exercise regimens.Potential risks,such as muscle and joint pain,are pointed out,emphasizing the importance of tailored,supervised exercise programs.The review calls for future research to focus on identifying the most effective types of exercise and regimens for this population,considering factors such as age,gender,and existing health conditions.Lastly,it advocates for the inclusion of exercise in comprehensive treatment plans for depression in older adults,viewing it as a promising step toward achieving holistic mental health care in a growing demographic.
基金supported by the Ministry of Science and Innovation and the Spanish Research Agency through FEDER funds (PID2021-1261520B-100) (MICINN/AEI/FEDER, EU)CBM receives an institutional grant from the Fundación Ramón Areces, Spain。
文摘The word “senescence” comes from the Latin senescens, meaning “to begin to age”, and is characterized by a long-lasting but reversible block in proliferation, resulting from stress-induced cell cycle arrest of previously replication-competent cells.
基金Supported by Operation and Improvement Program of Climate Monitoring,Warning and Assessment Services in Three Gorges Reservoir AreaNational Key Technology R&D Program (2007BAC29B06)+1 种基金Major State Basic Research Development 973 Program (2006CB400503)National Natural Science Foundation of China (40705031)
文摘Based on the meteorological data from 33 stations of Three Gorges Reservoir from 1960 to 2008,climate yield of rice,corn and winter wheat and the changes of climatic potential productivity after water storage in Three Gorges Reservoir were calculated by the dynamic statistic model of crop growth.The results showed that the temperature in Three Gorges Reservoir was fluctuant decreased before late 1980s,and warmed rapidly after the late 1980s.The precipitation had little change before the late 1990s and had a slight decrease after the late 1990s.Sunshine hours were more in 1960s and 1970s,and then it changed little after 1980s.After water storage,the temperature increased in Three Gorges Reservoir as a whole.The precipitation decreased in the south of Three Gorges Reservoir,while it increased in the northwest of Three Gorges Reservoir.The sunshine hours were reduced except that in the vicinity of Dianjiang.After water storage,climatic potential productivity of rice decreased in the northwest and the northeast,while it increased in the south of Three Gorges Reservoir.The climatic potential productivity of corn decreased in the northeast and the southwest,but increased in the rest of Three Gorges Reservoir.The climatic potential productivity of winter wheat increased almost in total.
基金Supported by Major Projects of State Water Pollution Control and Management (2008ZX07207-006-04)Shanghai Leading Academic Discipline Project (B604)~~
文摘[Objective] The paper was to study the dynamic changes of nitrogen in saline-alkaline paddy field and its potential environment impacts. [Method] With typical sodic saline-alkaline paddy fields of Songnen Plain as study object,field test method was used to explore the dynamic changes was strong alkof nitrogen in paddy field of the region and its potential impact on environment. [Result] The soil in test regionaline with high CEC and C/N ratios,as well as poor preserving capacity of fertilizer. During the two-year field experiment,the indicators of salinization fluctuated. Initially,the concentrations of total nitrogen and ammonia nitrogen reached their maximum values,then decreased over time as a result of heavy rain. The maximum of nitrate concentration appeared later than those of total nitrogen and ammonia nitrogen. Ammonia volatilization accounted for 18.9%-28.8% of the nitrogen loss. The total nitrogen concentration in surface water was higher than the national Class Ⅲ surface water environmental quality standard. The concentration of ammonia from the recession flow of agricultural field was considerably high,which would potentially threaten the fishery in the downstream of Chagan Lake. [Conclusion] The study provided theoretical basis for saline-alkaline soil management and conservation of water and fishery resources.
基金by the National Natural Science Foundation of China under Grant Nos.40405007 , 40275015 the OlympicProject under Grant No.KACX1-02 partially sup-ported by the"Outstanding Overseas Chinese Scholars"Project of the Chinese Academy of Sciences under Grant No.2002-1-2.
文摘The impacts of cloud-induced mass forcing on the development of the moist potential vorticity (MPV) anomaly associated with torrential rains are investigated by using NCEP/NCAR 1? × 1? data. The MPV tendency equation with the cloud-induced mass forcing is derived, and applied to the torrential rain event over the Changjiang River-Huaihe River Valleys during 26–30 June 1999. The result shows that positive anomalies are located mainly between 850 hPa and 500 hPa, while the maximum MPV, maximum positive tendency of the MPV, and maximum surface rainfall are nearly collocated. The cloud-induced mass forcing contributes to the positive tendency of the moist potential vorticity anomaly. The results indicate that the MPV may be used to track the propagation of rain systems for operational applications.
文摘The productivity exploitation degree,suitable exploitation degree and exploitable exploitation degree of production potential of winter wheat in three climate zones of Tianshui were calculated.The impacts of climate changes on it were analyzed.The results showed the exploitation degree of production potential of winter wheat was still low in the north of Wei River,the valley of Wei River and the area of Guan Mountain in Tianshui,being 49.9%-60.0%.Both the suitable exploitation degree and exploitable exploitation degree of production potential of winter wheat were comparatively high,being 73.6%-78.7% and 18.7%-23.8% respectively.The sequencing was the north of Wei River>the valley of Wei River>the area of Guan Mountain.In the long run,it was of great potential to be excavated.The average temperature,sunshine hours for growth season of winter wheat had negative effects on exploitation degree,suitable exploitation degree and exploitable degree of production potential of winter wheat.The precipitation had the positive effect.And the temperature in the entire growth period,temperature in autumn,the sunshine in winter had remarkable negative effects on the exploitation degree of the production potential in Tianshui and the north of Wei River.The precipitation in the entire growth period,the precipitation in autumn had remarkable positive effects in Tianshui and each climate zones.And some moderate development countermeasures of regional production potential were proposed.
基金supported by the Special Fund for Public Welfare Industry of Ministry of Water Resources of China(Grant No200901045)the Program for Changjiang Scholars and Innovative Research Team in University(Grant NoIRT0717)the 111 Project(Grant NoB08048)
文摘Evaporation, which is an important factor in the water balance at the basin scale, is a critical variable in the determination of local available water resources. Since the potential evaporation is mainly influenced by meteorological variables, it is necessary to investigate the extent to which different meteorological variables affect the potential evaporation. The aim of this study was to explore the variation trends of different meteorological variables, and their impacts on the potential evaporation. This study selected the Hailar Meteorological Station of the Hailar region, which is situated in a cold, semi-arid, and sub-humid region, as a case study site. Based on observed daily meteorological data from 1951 to 2009, the potential evaporation was calculated with the Penman formula, and the variations of meteorological variables were investigated with the nonparametric Mann-Kendall test. The correlation between the potential evaporation and each meteorological variable at annual and seasonal scales was also analyzed. The results show that the annual and seasonal potential evaporation and air temperature present increasing trends, whereas the wind speed, sunshine duration, and relative humidity present decreasing trends. Among the meteorological variables, the air temperature and relative humidity are the key factors that affect potential evaporation at different time scales, and the impacts of other meteorological variables on the potential evaporation are not significant and vary with time scales.
文摘An effective parameter in the miscible-CO_2 enhanced oil recovery procedure is the minimum miscibility pressure(MMP)defined as the lowest pressure that the oil in place and the injected gas into reservoir achieve miscibility at a given temperature. Flue gases released from power plants can provide an available source of CO_2,which would otherwise be emitted to the atmosphere, for injection into a reservoir. However, the costs related to gas extraction from flue gases is potentially high. Hence, greater understanding the role of impurities in miscibility characteristics between CO_2 and reservoir fluids helps to establish which impurities are tolerable and which are not. In this study, we simulate the effects of the impurities nitrogen(N_2), methane(C_1), ethane(C_2) and propane(C_3) on CO_2 MMP. The simulation results reveal that,as an impurity, nitrogen increases CO_2–oil MMP more so than methane. On the other hand, increasing the propane(C_3)content can lead to a significant decrease in CO_2 MMP, whereas varying the concentrations of ethane(C_2) does not have a significant effect on the minimum miscibility pressure of reservoir crude oil and CO_2 gas. The novel relationships established are particularly valuable in circumstances where MMP experimental data are not available.
基金supported by the National Natural Science Foundation of China (No. 51479185)the Major Basic Research Project of Shandong Province (No. ZR 2017ZA0202)
文摘The sea area east of Chenshan Cape has peak tidal current flows that exceed 2.3 m s^-1,which make it a promising site for the development of tidal current energy.Before these resources can be exploited,a comprehensive assessment is needed of the potential environmental impacts of the extraction of this energy.In this paper,we describe our construction of a three-dimensional hydrodynamic model of the waters near Chengshan Cape,and verify the performance of the model using continuous data measured in situ.We modeled the potential impacts of the exploitation of these resources on the flow field by adding a momentum loss term in the governing equation of the model.Simulation results show that an assumed tidal farm with an estimated power output of 20.34 MW would have a significant impact on the surrounding water level,especially next to the farm,where fluctuation could reach 6 cm.The maximum drop in the flow velocity in the wake of the farm was predicted to be more than 0.8 m s^-1,and this influence would extend 10 km downstream.
基金This study was supported by the funds from Sino-Africa Joint Research Center,CAS,China(Y323771W07 and SAJC201322)National Natural Science Foundation of China(31800176).
文摘Madagascar,a globally renowned biodiversity hotspot characterized by high rates of endemism,is one of the few remaining refugia for many plants and animal species.However,global climate change has greatly affected the natural ecosystem and endemic species living in Madagascar,and will likely continue to influence species distribution in the future.Madagascar is home to six endemic baobab(Adansonia spp.,Bombacoideae[Malvaceae])species(Adansonia grandidieri,A.suarezensis,A.madagascariensis,A.perrieri,A.rubrostipa,A.za),which are remarkable and endangered plants.This study aimed to model the current distribution of suitable habitat for each baobab species endemic to Madagascar and determine the effect that climate change will have on suitable baobab habitat by the years 2050 and 2070.The distribution was modeled using MaxEnt based on locality information of 245 occurrence sites of six species from both online database and our own field work.A total of seven climatic variables were used for the modeling process.The present distribution of all six Madagascar's baobabs was largely influenced by temperature-related factors.Although both expansion and contraction of suitable habitat are predicted for all species,loss of original suitable habitat is predicted to be extensive.For the most widespread Madagascar baobab,A.za,more than 40%of its original habitat is predicted to be lost because of climate change.Based on these findings,we recommend that areas predicted to contract in response to climate change should be designated key protection regions for baobab conservation.
基金The Xiamen Youth Innovation Fund under contract No.3502Z20206096the National Key Research and Development Program of China under contract No.2019YFE0124700+1 种基金the National Natural Science Foundation of China under contract Nos 42176153,41906127,and 42076163the National Program on Global Change and Air-Sea Interaction under contract No.HR01-200701.
文摘Climate change has affected and will continue to affect the spatial distribution patterns of marine organisms.To understand the impact of climate change on the distribution patterns and species richness of the Sciaenidae in China’s coastal waters,the maximum entropy model was used to combine six environmental factors and predict the potential distribution of 12 major species of Sciaenidae by 2050s under Representative Concentration Pathways(RCPs)2.6 and 8.5.The results showed that the average area under the receiver operating characteristic curve of the model was 0.917,indicating that the model predictions were accurate and reliable.The main driving factors affecting the potential distribution of these fishes were dissolved oxygen,salinity,and sea surface temperature(SST).There was an overall northward shift in the potential habitat areas of these fishes under the two climate scenarios.The total potential habitat areas of Larimichthys polyactis,Pennahia argentata,and Pennahia pawak decreased under both climate scenarios,while the total habitat area of Johnius belengerii,Pennahia anea,Miichthys miiuy,Collichthys lucidus,and Collichthys niveatus increased,suggesting that these might be loser and winner species,respectively.The expansion rate,contraction rate,degree of centroid change,and species richness in the potential habitats were generally more significant under RCP8.5 than RCP2.6.The mean shift rates of the potential distribution were 41.50 km/(10 a) and 29.20 km/(10 a) under RCP8.5 and RCP2.6,respectively.The changes in Sciaenidae species richness under climate change were bounded by the Changjiang River Estuary waters,with obvious north-south differences.Some waters with increased species richness may become refuges for Sciaenidae fishes under climate change.The richness and habitat area change rate of some aquatic germplasm resources will decrease,meanings that these reserves are more sensitive to climate change,and more attention should be paid to the potential challenges and opportunities for fishery managers.This study may provide a scientific basis for the management and conservation of Sciaenidae in China under climate change.
文摘BACKGROUND Oral potential malignant disorders(OPMDs)are a precancerous condition of oral disease.Several studies have found that betel quid chewing,smoking and alcohol drinking might be the risk factors of OPMDs.But the relationships of them,especially their interaction are still inconclusive.AIM To evaluate the relationship between betel quid chewing and OPMDs and to explore the interaction of smoking and alcohol drinking on the relationship.METHODS We searched Pub Med,Web of Science,Embase and the Cochrane Library databases with items complete until January 2021 for relevant studies.The research data were extracted according to the inclusion criteria.The pooled odds ratios(ORs)and 95%confidence intervals(CIs)were used to evaluate the effect size.Subgroup analysis was performed to assess interactions between exposures and OPMDs.Relative excess risk of interaction(RERI)was used to estimate the size of interaction.RESULTS Nine articles were selected in the final meta-analysis.The results showed that betel quid chewing(pooled OR:8.70,95%CI:5.18-14.61),alcohol consumption(pooled OR:1.95,95%CI:1.5-2.55),and smoking(pooled OR:4.35,95%CI:3.06-6.2)could significantly increase the risk of OPMDs compared to individuals without these behaviors.Smoking and alcohol drinking synergistically increased the association between betel quid chewing and OPMDs(pooled OR;:14.38,95%CI:7.14-28.95;pooled OR;:11.12,95%CI:8.00-15.45,respectively).The RERI;and RERI;were 2.33 and 1.47,respectively.CONCLUSION The synergistic effects between smoking/drinking and betel quid highlights the importance of focusing on individuals with multiple exposures.Further study should be conducted to confirm these interactions.
基金s We acknowledged the financial support of the National Key Research and Development Program of China (2018YFB1502803), the National Natural Science Foundation of China (41475066), and Tsinghua University Initiative Sci entific Research Program (20131089357, 20131089356).
文摘Wind energy has been rapidly developed in China during the past decades and the installed capacity has been the largest in the world. In the future, utilization of wind power is still expected to carry out in China mainly with a large-scale centralized layout. Here, we examine the potential climatic impacts of large-scale windfarms associated with deployment scale in China using numerical experiments, in which four deployment scenarios were designed. These four scenarios represented relatively small- (484 GW), medium- (2165 GW) and large-scale (3490 GW and 5412 GW) installed wind power capacities, respectively. Results showed that turbulent kinetic energy, wind velocity, and air temperature varied consistently within those windfarms with the largest changes in turbine hub heights. Moreover, the above relatively large- scale windfarms could induce regional wanning with a maximum of above 0.8 °C in North China. This regional warming may be linked to an anomalous circulation pattern with a negative pressure anomaly center in Northeast China and a positive pressure anomaly center in the middle and lower reaches of the Yangtze-Huaihe River Basin.
文摘Climate warming is expected to influence forest growth,composition and distribution.However,accurately estimating and predicting forest biomass,potential productivity or forest growth is still a challenge for forest managers dealing with land-use at the stand to regional levels.In the present study,we predicted the potential productivity(PP)of forest under current and future climate scenarios(RCP2.6,RCP4.5,RCP6.0 and RCP8.5)in Jilin province,northeastern China by using Paterson’s Climate Vegetation and Productivity(CVP)index model.The PP was validated by comparing it with the mean and maximum net primary production calculated from light energy utilization(GLM_PEM).Our results indicated that using the CVP index model is partially valid for predicting the potential forest productivity in northeastern China.PP exhibited obvious spatial heterogeneity varying from 4.6 to 8.9 m3 ha-1 year-1 with an increasing tendency from northwest to southeast driven by the precipitation across the region.The number of vegetation-active months,precipitation and insolation coefficient were identified as the primary factors affecting PP,but no significant relationship was found for warmest temperature or temperature fluctuation.Under future climate scenarios,PP across the Jilin Province is expected to increase from 1.38%(RCP2.6 in 2050)to 15.30%(RCP8.5 in 2070),especially in the eastern Songnen Plain(SE)for the RCP8.5 scenarios.
文摘The emissions of greenhouse gasses in Egypt are about 0.58% of the total emissions of the world in the year 2015, although Egypt is one of the countries most affected by the impacts of climate change. By assessment and analysis of the expected economic impacts of climate change by the year 2030, the Egyptian cultivated area will be reduced to about 0.949 million acres, equal to about 8.22% of the Egyptian cultivated area compared with the case of no sinking part of the Delta land, thus reducing crop area in Egypt to about 1.406 million acres, approximately to about 6.25% of crop area compared with the case of no sinking part of the Delta land, in addition to surplus in the Egyptian balance water to about 2.48 billion m3. In this case value of the Egyptian agriculture production will decrease by about 6.19 billion dollars, equal to about 6.19% compared with presumably no sinking of the Delta land. In the case of sinking 15% of Delta lands, with the change of the productivity and water consumption of most crops, the result will be a reduction in the cultivated area to about 0.94 million acres. In addition to decreasing the Egyptian crop area to about 1.39 million acres, with a deficit in the Egyptian balance water to about 4.74 billion m3 compared to the case of no sinking part of the Delta land, the cultivated area will decrease to about 8.17%, and the crop area will decrease 6.18%. Also, the value of the Egyptian agriculture production will decrease by about 12.51%. While compared to sinking part of the Delta land to about 15% of the total Delta area without the other impacts of climate change, the cultivated area will increase by about 0.06%;the crop area will increase by about 0.08%;also, the value of the Egyptian agriculture production will decrease by about 5.57%.
文摘Ecotourism has been suggested as the altemative for the conflicts between tourism development and nature conservation especially for the protected area, such as biosphere reserve. Based on investigation of tourism resources of The Changbaishan Biosphere Reserve (CBR) and tourism impacts on environment, economy and society, the potential of ecotourism development is analyzed in and around CBR. The results showed that the conditions in the study area are suitable for development of ecotourism, which is an effective approach for sustainable development of CBR.
基金the National Natural Science Foundation of China(Grant Nos.62227901,12202068)the Civil Aerospace Pre-research Project(Grant No.D020304).
文摘The effects of projectile/target impedance matching and projectile shape on energy,momentum transfer and projectile melting during collisions are investigated by numerical simulation.By comparing the computation results with the experimental results,the correctness of the calculation and the statistical method of momentum transfer coefficient is verified.Different shapes of aluminum,copper and heavy tungsten alloy projectiles striking aluminum,basalt,and pumice target for impacts up to 10 km/s are simulated.The influence mechanism of the shape of the projectile and projectile/target density on the momentum transfer was obtained.With an increase in projectile density and length-diameter ratio,the energy transfer time between the projectile and targets is prolonged.The projectile decelerates slowly,resulting in a larger cratering depth.The energy consumed by the projectile in the excavation stage increased,resulting in lower mass-velocity of ejecta and momentum transfer coefficient.The numerical simulation results demonstrated that for different projectile/target combinations,the higher the wave impedance of the projectile,the higher the initial phase transition velocity and the smaller the mass of phase transition.The results can provide theoretical guidance for kinetic impactor design and material selection.