A frozen soil parameterization coupling of thermal and hydrological processes is used to investigate how frozen soil processes affect water and energy balances in seasonal frozen soil. Simulation results of soil liqui...A frozen soil parameterization coupling of thermal and hydrological processes is used to investigate how frozen soil processes affect water and energy balances in seasonal frozen soil. Simulation results of soil liquid water content and temperature using soil model with and without the inclusion of freezing and thawing processes are evaluated against observations at the Rosemount field station. By comparing the simulated water and heat fluxes of the two cases, the role of phase change processes in the water and energy balances is analyzed. Soil freezing induces upward water flow towards the freezing front and increases soil water content in the upper soil layer. In particular, soil ice obviously prevents and delays the infiltration during rain at Rosemount. In addition, soil freezingthawing processes alter the partitioning of surface energy fluxes and lead the soil to release more sensible heat into the atmosphere during freezing periods.展开更多
This article utilizes a large amount of statistical data to analyze the global distribution of foreign trade in China since 1990,as well as the factors involved and the changes in trends.The research results indicate ...This article utilizes a large amount of statistical data to analyze the global distribution of foreign trade in China since 1990,as well as the factors involved and the changes in trends.The research results indicate that China has gained a favourable balance against developed countries and a disadvantageous balance against developing countries;China enjoys a trade surplus with North American and European countries while suffering deficits with those in the Asia.pacific region,as well as with resource-abundant Australia,Africa and South America. With regard to trends,the structure of China’s foreign trade will not undergo fundamental changes in the short term,but in the long run will be transformed in line with restructuring of the growth pattern.展开更多
Nitrogen, phosphorus, and potassium balances for agroecosystems in China from 1993 to 2001 were calculated at national and provincial levels using statistical data and related parameters, and their spatial and tempora...Nitrogen, phosphorus, and potassium balances for agroecosystems in China from 1993 to 2001 were calculated at national and provincial levels using statistical data and related parameters, and their spatial and temporal variabilities were analyzed with GIS to estimate the potential impacts of nutrient N, P and K surpluses or deficits to soil, water and air. At the national scale, the N and P balances from 1993 to 2001 showed a surplus, with the nitrogen surplus remaining relatively stable from 1997—2001. Although during this period the P surplus pattern was similar to N, it had smaller values and kept increasing as the use of phosphate fertilizer increased year by year. However, K was deficient from 1993 to 2001 even though from 1999 to 2001 the K deficit decreased. The spatial analysis revealed higher N surpluses in the more developed southeastern provinces and lowest in the western and northern provinces where there was less chemical fertilizer input. The serious K deficit mainly occurred in Shanghai and Beijing municipalities, Jiangsu, Zhejiang and Hubei provinces, and Xinjiang autonomous regions. For the years 1992, 1996 and 2001, N surpluses and K deficits had significant positive spatial correlations with per capita gross domestic product (GDP), per capita gross industrial output value, and per capita net income of rural households. This showed that the level of economic development played an important role on nutrient balances in the agroecosystems.展开更多
Surface nitrogen (N) balances for China's crop production systems was estimated using statistical data collected from 1980 to 2004 at the national and provincial scale and from 1994 to 1999 at the county level. The...Surface nitrogen (N) balances for China's crop production systems was estimated using statistical data collected from 1980 to 2004 at the national and provincial scale and from 1994 to 1999 at the county level. There was a surplus N balance throughout these periods, but the surplus was nearly stable in recent years. Projections using nonseasonal Box-Jenkins model or exponential models show that the N surplus for the total cultivated land in China was likely to increase from 142.8 kg ha^-1 in 2004 to 168.6 kg ha 1 in 2015. The N balance surplus in the more developed southeastern provinces was the largest, and was slightly less in the central region, which caused the nitrate pollution in the ground water. The N surplus was much less in the western and northern provinces because of lower synthetic fertilizer inputs. The region with high N risk includes Beijing Municipality and Jiangsu, Zhejiang, Fujian, Guangdong, Hubei, and Shandong provinces for 2002-2004. The projections suggested that 15 provinces (or municipalities) in the middle and southeastern part of China except Jiangxi and Shanxi provinces would become the high-risk region by 2015. The level of economic development, transportation, and labor force condition had an important effect on the N balance surplus at the county level, but the last two factors showed remarkable impact at the provincial level. To decrease the nonpoint pollution (Npp) risk from crop production, the authors suggested to reduce the target level for national grain self-sufficiency to 90%-95% and change the regional structure of grain production by moving some of the future grain production from the high Npp risk areas of eastern China to parts of the central and western provinces where the Npp risk was much less.展开更多
Global nitrogen (N) budgets for intensive agricultural systems were compiled for a 0.5 by 0.5 degree resolution. These budgets include N inputs (N fertilizer, animal manure, biological N fixation and atmospheric N dep...Global nitrogen (N) budgets for intensive agricultural systems were compiled for a 0.5 by 0.5 degree resolution. These budgets include N inputs (N fertilizer, animal manure, biological N fixation and atmospheric N deposition) and outputs (N removal from the field in harvested crops and grass and grass consumption by grazing animals, ammonia volatilization,denitrification and leaching). Data for the historical years 1970 and 1995 and a projection for 2030 were used to study changes in the recovery of N and the different loss terms for intensive agricultural systems. The results indicate that the overall system N recovery and fertilizer use efficiency slowly increased in the industrialized countries between 1970 and 1995, the values for developing countries have decreased in the same period. For the coming three decades our results indicate a rapid increase in both the industrialized and developing countries. High values of > 80% for fertilizer use efficiency may be related to surface N balance deficits, implying a depletion of soil N and loss of soil fertility. The projected intensification in most developing countries will cause a gradual shift from deficits to surpluses in the coming decades.The projected fast growth of crop and livestock production, and intensification and associated increase in fertilizer inputs will cause a major increase in the surface N balance surplus in the coming three decades. This implies increasing losses of N compounds to air (ammonia, nitrous oxide and nitric oxide), and groundwater and surface water (nitrate).展开更多
Because of the almast enclosed nature of the Bohai Sea, rivers are considered as the sources of the major seawater chemical constituents there. The annual quantities of river-derived solutes and solids in Bohai Sea wa...Because of the almast enclosed nature of the Bohai Sea, rivers are considered as the sources of the major seawater chemical constituents there. The annual quantities of river-derived solutes and solids in Bohai Sea water are accurately calculated in this paper.展开更多
The removal processes of major seawater chemical constituents in the Bohai Sea include seawater ex-change between the Bohai Sea and the Northern Yellow Sea,cation exchange,interstitial water burialand spray,formation ...The removal processes of major seawater chemical constituents in the Bohai Sea include seawater ex-change between the Bohai Sea and the Northern Yellow Sea,cation exchange,interstitial water burialand spray,formation of illite,sepiolite,sulfate and sulfur,and carbonates.The mass balance calculationbased on these processes is very applicable to the Bohai Sea.展开更多
At high latitudes and in mountainous areas, evaluation and validation of water and energy flux simu-lations are greatly affected by systematic precipitation errors. These errors mainly come from topographic effects an...At high latitudes and in mountainous areas, evaluation and validation of water and energy flux simu-lations are greatly affected by systematic precipitation errors. These errors mainly come from topographic effects and undercatch of precipitation gauges. In this study, the Land Dynamics (LAD) land surface model is used to investigate impacts of systematic precipitation bias from topography and wind-blowing on water and energy flux simulation in Northwest America. The results show that topographic and wind adjustment reduced bias of streamflow simulations when compared with observed streamflow at 14 basins. These systematic biases resulted in a -50%-100% bias for runoff simulations, a -20%-20% bias for evapotranspiration, and a -40%-40% bias for sensible heat flux, subject to different locations and adjustments, when compared with the control run. Uncertain gauge adjustment leads to a 25% uncertainty for precipitation, a 20% 100% uncertainty for runoff simulation, a less-than-10% uncertainty for evapotranspiration, and a less-than-20% uncertainty for sensible heat flux.展开更多
Rheumatoid arthritis (RA) is the most common chronic autoimmune joint disease. The etiology of RA is complex, and then it is impossible to cure completely today and it should be individualized treatment. Immune system...Rheumatoid arthritis (RA) is the most common chronic autoimmune joint disease. The etiology of RA is complex, and then it is impossible to cure completely today and it should be individualized treatment. Immune system is complex. Existing statistical techniques based on reductionism cannot discover many relevant disease risk factors and complex interaction relationship. The disease network model based on complex network is important for the analysis and treatment of RA disease. In this Review, we have found five important layers of RA complex network and presented five balances regulating strategy in the management of RA. We have followed up one RA patient (wife of the author) for one year using this strategy, and the management effect is good. This Review argues RA is self-limiting to some extent, and good management with five balances regulating strategy would have positive significance, among which the balance between neuroendocrine system and immune system is the most important. During the day, glucocorticoid plays an important role in con-trolling inflammation, and human growth hormone plays an important role in eliminating inflammation during the slow-wave sleep at night. Five balances core concepts can shed light on the management of other causes of arthritis.展开更多
This article analyzes the internal and external imbalances of China’s economy from a global perspective. The author believes that trade surplus and savings surplus are not the absolute metrics to define a country’s ...This article analyzes the internal and external imbalances of China’s economy from a global perspective. The author believes that trade surplus and savings surplus are not the absolute metrics to define a country’s economic strength. China’s balance of payments has continued to maintain a big surplus, which shows China’s unique economic structure and growth model and exposes deep contradictions in income distribution, factor prices and resource allocation. While stimulating rapid growth, the imbalance of China’s economy, at the same time, has long delayed the upgrading of industrial structure, aggravating the threat of inflation and heightening concerns of an asset bubble. Although the external and internal imbalances are closely linked to each other, they are quite different in nature. This similar global economic imbalance has existed for a long time, and to a great extent, is inevitable and rational. However, internal imbalances caused by its own systems and policies, if lasted, would have severe and negative impacts not only on China’s economy, but on the global economy as a whole.展开更多
Muscle imbalances are a well accepted cause of musculo-skeletal pain, yet clinicians lack a simple, non-invasive, and reproducible means to assess muscle effort during activities of daily living. To address this issue...Muscle imbalances are a well accepted cause of musculo-skeletal pain, yet clinicians lack a simple, non-invasive, and reproducible means to assess muscle effort during activities of daily living. To address this issue, we have been developing vibromyography (VMG) as a means to quantitatively assess muscle mechanical effort such that accurate muscle effort ratios can be determined in the clinic. In this study, VMG was used to characterize muscle imbalances in older adults with low-level knee pain while they performed step-up and step-down activities. In addition to determining whether VMG can identify the imbalances previously reported in individuals with knee pain, we address the question of whether these knee muscle imbalances were a likely cause of knee pain, or whether the imbalances represented a coping response for pre-existing knee pain. A population (N = 30) of 35 - 85 year old men and women with a total of 42 painful knees were assessed. Robust multiple step-wise regression analysis identified weak hip abductor muscle effort relative to hamstring muscle effort as the best predictor of knee pain (p = 0.00006), with weak vastus lateralis effort in eccentric contraction, relative to concentric contraction, being the second best predictor (p = 0.0003). Muscle imbalances were able to account for 40% of the variation in reported pain, and the observed pattern of increasing knee pain with increasing quadriceps strength during concentric contraction leads us to infer that the observed muscle imbalances are not the result of a protective action by the individual, but rather are a principle cause of the knee pain.展开更多
The principal contradiction facing the Chinese society has evolved to be that between imbalanced and inadequate development and the people’s ever-growing needs for a better life.Given China’s vision for achieving mo...The principal contradiction facing the Chinese society has evolved to be that between imbalanced and inadequate development and the people’s ever-growing needs for a better life.Given China’s vision for achieving moderate prosperity,it is relevant to conduct theoretical and empirical studies on the nation’s development imbalances.As a quantitative index,the Tsinghua China Balanced Development Index measures the extent to which development is uneven and insuf ficient across regions,re flecting the progress and shortfalls in China’s efforts to promote balanced development.Our findings provide implications for how policymakers may help people’s expectations for a better life materialize by spurring balanced economic,social,environmental and livelihood development across regions.展开更多
Despite all of the many discrepancies and contradictions in the estimate of the water balance in the Barada Awaj basin, all the research and reports, both local and international, indicate that the basin suffers from ...Despite all of the many discrepancies and contradictions in the estimate of the water balance in the Barada Awaj basin, all the research and reports, both local and international, indicate that the basin suffers from water depletion. The agricultural sector is the largest consumer of water, and the area of land irrigated by the basin has risen significantly. Rapid population growth as a result of natural increase and massive immigration to the basin, piratical well-digging without permits, the failure to increase the area of land irrigated by modern methods and a decrease in rainfall and the drought that has affected Syria in general and the Barada Awaj basin in particular, have led to a water shortage in the basin during the first decade of this century.展开更多
Demographic transitions occur at different times and speed across different economies, and age structures consequently differ across regions. Using a solvable four-phase model, we show that economies with a higher pro...Demographic transitions occur at different times and speed across different economies, and age structures consequently differ across regions. Using a solvable four-phase model, we show that economies with a higher proportion of working-age force and a lower dependency ratio tend to have higher savings rates. Because the demographic " center of gravity"for investment demand falls at a younger point in the age distribution than that of savings supply, countries with a younger age-distribution like those described above generate national savings in excess of domestic investment, resulting in a current account surplus. Numerical simulation supports this hypothesis. But the relative youth or age of a country's population reflects temporary demographic trends which change continuously. Therefore, while trade imbalances caused by demographic factors are structural and long-term, they are not permanent, and may be reversed by changes in age structure.展开更多
The seasonal changes in the energy balance after the substitution of a herbaceous savanna by a Brachiaria field located in the Orinoco lowlands were assessed over an entire year using the eddy covariance technique. Si...The seasonal changes in the energy balance after the substitution of a herbaceous savanna by a Brachiaria field located in the Orinoco lowlands were assessed over an entire year using the eddy covariance technique. Simultaneously, an herbaceous savanna was monitored as a control. This work provides evidence that the vegetation replacement lead to different patterns of energy and water balance. The seasonal trends of the latent heat flux (λE) to available energy (Ra) ratio tended to decrease as senescence increased due to seasonal influence of air humidity mole fraction deficit and soil water content on leaf area index (LAI) and surface conductance (gs). Therefore, the partitioning of the available energy depended on both climatological (i.e., solar radiation, volumetric soil water content and air humidity mole fraction deficit) and biological variables (i.e., conductance behavior and LAI) which were stress-induced. For the wet season, the seasonally averaged daily λE in the Brachiaria field (i.e., 0.8 ± 0.1 mm d^-1) was 1.3-fold higher than that in the herbaceous savanna (i.e., 0.6 ± 0.1 mm d-1)(Mann-Whitney U-test). For the dry season, the value was 2.7 ± 0.6 and 2.2 ± 0.4 mm d-1, respectively, these means values were not significantly different. In the Brachiaria and herbaceous savanna stands, the annual evapotranspiration was 731 and 594 mm year^-1, respectively, and the annual ratio of evapotranspiration to precipitation was 0.52 to 0.42 respectively. In Brachiaria field, the deep drainage was relatively lower (43% of total precipitation) than that in the herbaceous savanna stand (53%) leaving a similar amount of water to increase soil storage. The current shift in land cover decrease deep drainage and increased λE by water uptake from a pasture with high belowground phytomass and LAI.展开更多
Looking back at over a decade of research by herself and her group,the author advocates the added value of gas phase measurements and the application of mass balances,as well as the synergetic benefits obtained when c...Looking back at over a decade of research by herself and her group,the author advocates the added value of gas phase measurements and the application of mass balances,as well as the synergetic benefits obtained when combining both.The increased application of off-gas measurements for greenhouse gas emission monitoring offers a great opportunity to look at other components in the gas phase,particularly oxygen.Mass balances should not be strictly reserved for modellers but also prove useful while conducting lab experiments and studying full-scale measurement data.Combining off-gas measurements with mass balances may serve not only to quantify greenhouse gas emission factors and aeration efficiency but also to follow dynamic concentration profiles of dissolved components without dedicated sensors and/or to calculate other unmeasured variables.Mass-balance-based data reconciliation allows for obtaining reliable and accurate data,and even more when combined with off-gas analysis.展开更多
This study, which assesses the quality of soils under cocoa trees in the Marahoué region of Côte d’Ivoire, is being carried out against a backdrop of declining crop yields due to a number of factors, includ...This study, which assesses the quality of soils under cocoa trees in the Marahoué region of Côte d’Ivoire, is being carried out against a backdrop of declining crop yields due to a number of factors, including the loss of soil fertility. The aim was to identify homogeneous groups of soils in terms of fertility and propose sustainable management methods for each group. The study was carried out on twenty-four cocoa orchards belonging to the SCOOP KAPATCHIVA cooperative, spread over eight sectors. A morphological characterisation of the soils was carried out in the field, followed by physico-chemical laboratory analyses of soil samples taken in the field. Soil fertility was analyzed on the basis of these two groups of data. The results showed that soil depths were generally high, except in some high altitude areas, where soils were often enriched in ferromagnesian elements and compacted. The texture of the soils varied between loamy and sandy-loamy, influencing cocoa production. Indeed, the soils of the plots with high production were looser and without ferromagnesian concretions, while those of the plots with low production were more gravelly and compact. Biological activity in the upper soil layer (0 - 30 cm) was notable with an abundance of termites and earthworms. The organic matter and nitrogen content varies considerably between sectors, directly impacting soil fertility. The soils were slightly acidic and showed significant differences in the levels of exchangeable magnesium and potassium, and not at all for phosphorus which appeared at very low doses. Chemical analysis also revealed that nutrient balance was a key factor in orchard productivity, with varying ratios of calcium, magnesium and potassium. Knowledge of these results made it possible to make recommendations for soil management with a view to improving cocoa yields in the study area.展开更多
Phosphorus bioavailability has long been a recurring problem in tropical acid soils. A pot experiment was carried out during three (3) successive rice production cycles at Adiopodoumé to evaluate the response of ...Phosphorus bioavailability has long been a recurring problem in tropical acid soils. A pot experiment was carried out during three (3) successive rice production cycles at Adiopodoumé to evaluate the response of the NERICA 5 rice accession to various doses of calcium, magnesium and phosphorous. The experiment was conducted using a randomized split-plot design. The interactive effects of calcium carbonate (0, 25, 50 and 75 kg·Ca·ha<sup>-1</sup>) and magnesium sulfate (0, 25, 50 and 75 kg·Mg·ha<sup>-1</sup>) and Togo natural phosphate (0, 25, 50 and 75 kg·P·ha<sup>-1</sup>) were determined at each production cycle. The results showed that single-dose natural phosphate supplementation for three cropping cycles resulted in an average enrichment of around 2 mg·P·kg<sup>-1</sup> after each trial following its continuous dissolution, with an increase in DSP (33.31% to 70.52%). The study revealed one strategy for managing and enhancing native P with cations and another for exogenous P: there would be a synergy of Ca/Mg on native P, whereas an antagonism would characterize the two parameters in phosphate fertilization.展开更多
Na^(+)/K^(+)-ATPase is a transmembrane protein that has important roles in the maintenance of electrochemical gradients across cell membranes by transporting three Na^(+)out of and two K^(+)into cells.Additionally,Na^...Na^(+)/K^(+)-ATPase is a transmembrane protein that has important roles in the maintenance of electrochemical gradients across cell membranes by transporting three Na^(+)out of and two K^(+)into cells.Additionally,Na^(+)/K^(+)-ATPase participates in Ca^(2+)-signaling transduction and neurotransmitter release by coordinating the ion concentration gradient across the cell membrane.Na^(+)/K^(+)-ATPase works synergistically with multiple ion channels in the cell membrane to form a dynamic network of ion homeostatic regulation and affects cellular communication by regulating chemical signals and the ion balance among different types of cells.Therefo re,it is not surprising that Na^(+)/K^(+)-ATPase dysfunction has emerged as a risk factor for a variety of neurological diseases.However,published studies have so far only elucidated the important roles of Na^(+)/K^(+)-ATPase dysfunction in disease development,and we are lacking detailed mechanisms to clarify how Na^(+)/K^(+)-ATPase affects cell function.Our recent studies revealed that membrane loss of Na^(+)/K^(+)-ATPase is a key mechanism in many neurological disorders,particularly stroke and Parkinson's disease.Stabilization of plasma membrane Na^(+)/K^(+)-ATPase with an antibody is a novel strategy to treat these diseases.For this reason,Na^(+)/K^(+)-ATPase acts not only as a simple ion pump but also as a sensor/regulator or cytoprotective protein,participating in signal transduction such as neuronal autophagy and apoptosis,and glial cell migration.Thus,the present review attempts to summarize the novel biological functions of Na^(+)/K^(+)-ATPase and Na^(+)/K^(+)-ATPase-related pathogenesis.The potential for novel strategies to treat Na^(+)/K^(+)-ATPase-related brain diseases will also be discussed.展开更多
One of the basic characteristics of Earth's modern climate is that the Northern Hemisphere(NH) is climatologically warmer than the Southern Hemisphere(SH). Here, model performances of this basic state are examined...One of the basic characteristics of Earth's modern climate is that the Northern Hemisphere(NH) is climatologically warmer than the Southern Hemisphere(SH). Here, model performances of this basic state are examined using simulation results from 26 CMIP6 models. Results show that the CMIP6 models underestimate the contrast in interhemispheric surface temperatures on average(0.8 K for CMIP6 mean versus 1.4 K for reanalysis data mean), and that there is a large intermodel spread, ranging from -0.7 K to 2.3 K. A box model energy budget analysis shows that the contrast in interhemispheric shortwave absorption at the top of the atmosphere, the contrast in interhemispheric greenhouse trapping, and the crossequatorial northward ocean heat transport, are all underestimated in the multimodel mean. By examining the intermodel spread, we find intermodel biases can be tracked back to biases in midlatitude shortwave cloud forcing in AGCMs. Models with a weaker interhemispheric temperature contrast underestimate the shortwave cloud reflection in the SH but overestimate the shortwave cloud reflection in the NH, which are respectively due to underestimation of the cloud fraction over the SH extratropical ocean and overestimation of the cloud liquid water content over the NH extratropical continents.Models that underestimate the interhemispheric temperature contrast exhibit larger double ITCZ biases, characterized by excessive precipitation in the SH tropics. Although this intermodel spread does not account for the multimodel ensemble mean biases, it highlights that improving cloud simulation in AGCMs is essential for simulating the climate realistically in coupled models.展开更多
基金supported by the National Basic Research Program of China under Grant No 2006CB400504National Natural Science Foundation of China under Grant Nos 40605027 and 40775050
文摘A frozen soil parameterization coupling of thermal and hydrological processes is used to investigate how frozen soil processes affect water and energy balances in seasonal frozen soil. Simulation results of soil liquid water content and temperature using soil model with and without the inclusion of freezing and thawing processes are evaluated against observations at the Rosemount field station. By comparing the simulated water and heat fluxes of the two cases, the role of phase change processes in the water and energy balances is analyzed. Soil freezing induces upward water flow towards the freezing front and increases soil water content in the upper soil layer. In particular, soil ice obviously prevents and delays the infiltration during rain at Rosemount. In addition, soil freezingthawing processes alter the partitioning of surface energy fluxes and lead the soil to release more sensible heat into the atmosphere during freezing periods.
文摘This article utilizes a large amount of statistical data to analyze the global distribution of foreign trade in China since 1990,as well as the factors involved and the changes in trends.The research results indicate that China has gained a favourable balance against developed countries and a disadvantageous balance against developing countries;China enjoys a trade surplus with North American and European countries while suffering deficits with those in the Asia.pacific region,as well as with resource-abundant Australia,Africa and South America. With regard to trends,the structure of China’s foreign trade will not undergo fundamental changes in the short term,but in the long run will be transformed in line with restructuring of the growth pattern.
基金1Project supported by the Knowledge Innovation Program of Chinese Academy of Sciences (No. KZCX2-413).
文摘Nitrogen, phosphorus, and potassium balances for agroecosystems in China from 1993 to 2001 were calculated at national and provincial levels using statistical data and related parameters, and their spatial and temporal variabilities were analyzed with GIS to estimate the potential impacts of nutrient N, P and K surpluses or deficits to soil, water and air. At the national scale, the N and P balances from 1993 to 2001 showed a surplus, with the nitrogen surplus remaining relatively stable from 1997—2001. Although during this period the P surplus pattern was similar to N, it had smaller values and kept increasing as the use of phosphate fertilizer increased year by year. However, K was deficient from 1993 to 2001 even though from 1999 to 2001 the K deficit decreased. The spatial analysis revealed higher N surpluses in the more developed southeastern provinces and lowest in the western and northern provinces where there was less chemical fertilizer input. The serious K deficit mainly occurred in Shanghai and Beijing municipalities, Jiangsu, Zhejiang and Hubei provinces, and Xinjiang autonomous regions. For the years 1992, 1996 and 2001, N surpluses and K deficits had significant positive spatial correlations with per capita gross domestic product (GDP), per capita gross industrial output value, and per capita net income of rural households. This showed that the level of economic development played an important role on nutrient balances in the agroecosystems.
基金the Chinese Academy of Sciences (NoKZCX2-YW-N-038)the National Basic Research Program of China (No2005CB121108)
文摘Surface nitrogen (N) balances for China's crop production systems was estimated using statistical data collected from 1980 to 2004 at the national and provincial scale and from 1994 to 1999 at the county level. There was a surplus N balance throughout these periods, but the surplus was nearly stable in recent years. Projections using nonseasonal Box-Jenkins model or exponential models show that the N surplus for the total cultivated land in China was likely to increase from 142.8 kg ha^-1 in 2004 to 168.6 kg ha 1 in 2015. The N balance surplus in the more developed southeastern provinces was the largest, and was slightly less in the central region, which caused the nitrate pollution in the ground water. The N surplus was much less in the western and northern provinces because of lower synthetic fertilizer inputs. The region with high N risk includes Beijing Municipality and Jiangsu, Zhejiang, Fujian, Guangdong, Hubei, and Shandong provinces for 2002-2004. The projections suggested that 15 provinces (or municipalities) in the middle and southeastern part of China except Jiangxi and Shanxi provinces would become the high-risk region by 2015. The level of economic development, transportation, and labor force condition had an important effect on the N balance surplus at the county level, but the last two factors showed remarkable impact at the provincial level. To decrease the nonpoint pollution (Npp) risk from crop production, the authors suggested to reduce the target level for national grain self-sufficiency to 90%-95% and change the regional structure of grain production by moving some of the future grain production from the high Npp risk areas of eastern China to parts of the central and western provinces where the Npp risk was much less.
基金Project supported by the Netherlands Environmental Assessment Agency, National Institute for Public Health and the Environment (No. S/550005/01/DD) the Canadian International Development Agency, Canada and the Chinese Academy of Sciences, China (No.KZCX2-413)
文摘Global nitrogen (N) budgets for intensive agricultural systems were compiled for a 0.5 by 0.5 degree resolution. These budgets include N inputs (N fertilizer, animal manure, biological N fixation and atmospheric N deposition) and outputs (N removal from the field in harvested crops and grass and grass consumption by grazing animals, ammonia volatilization,denitrification and leaching). Data for the historical years 1970 and 1995 and a projection for 2030 were used to study changes in the recovery of N and the different loss terms for intensive agricultural systems. The results indicate that the overall system N recovery and fertilizer use efficiency slowly increased in the industrialized countries between 1970 and 1995, the values for developing countries have decreased in the same period. For the coming three decades our results indicate a rapid increase in both the industrialized and developing countries. High values of > 80% for fertilizer use efficiency may be related to surface N balance deficits, implying a depletion of soil N and loss of soil fertility. The projected intensification in most developing countries will cause a gradual shift from deficits to surpluses in the coming decades.The projected fast growth of crop and livestock production, and intensification and associated increase in fertilizer inputs will cause a major increase in the surface N balance surplus in the coming three decades. This implies increasing losses of N compounds to air (ammonia, nitrous oxide and nitric oxide), and groundwater and surface water (nitrate).
文摘Because of the almast enclosed nature of the Bohai Sea, rivers are considered as the sources of the major seawater chemical constituents there. The annual quantities of river-derived solutes and solids in Bohai Sea water are accurately calculated in this paper.
文摘The removal processes of major seawater chemical constituents in the Bohai Sea include seawater ex-change between the Bohai Sea and the Northern Yellow Sea,cation exchange,interstitial water burialand spray,formation of illite,sepiolite,sulfate and sulfur,and carbonates.The mass balance calculationbased on these processes is very applicable to the Bohai Sea.
文摘At high latitudes and in mountainous areas, evaluation and validation of water and energy flux simu-lations are greatly affected by systematic precipitation errors. These errors mainly come from topographic effects and undercatch of precipitation gauges. In this study, the Land Dynamics (LAD) land surface model is used to investigate impacts of systematic precipitation bias from topography and wind-blowing on water and energy flux simulation in Northwest America. The results show that topographic and wind adjustment reduced bias of streamflow simulations when compared with observed streamflow at 14 basins. These systematic biases resulted in a -50%-100% bias for runoff simulations, a -20%-20% bias for evapotranspiration, and a -40%-40% bias for sensible heat flux, subject to different locations and adjustments, when compared with the control run. Uncertain gauge adjustment leads to a 25% uncertainty for precipitation, a 20% 100% uncertainty for runoff simulation, a less-than-10% uncertainty for evapotranspiration, and a less-than-20% uncertainty for sensible heat flux.
文摘Rheumatoid arthritis (RA) is the most common chronic autoimmune joint disease. The etiology of RA is complex, and then it is impossible to cure completely today and it should be individualized treatment. Immune system is complex. Existing statistical techniques based on reductionism cannot discover many relevant disease risk factors and complex interaction relationship. The disease network model based on complex network is important for the analysis and treatment of RA disease. In this Review, we have found five important layers of RA complex network and presented five balances regulating strategy in the management of RA. We have followed up one RA patient (wife of the author) for one year using this strategy, and the management effect is good. This Review argues RA is self-limiting to some extent, and good management with five balances regulating strategy would have positive significance, among which the balance between neuroendocrine system and immune system is the most important. During the day, glucocorticoid plays an important role in con-trolling inflammation, and human growth hormone plays an important role in eliminating inflammation during the slow-wave sleep at night. Five balances core concepts can shed light on the management of other causes of arthritis.
文摘This article analyzes the internal and external imbalances of China’s economy from a global perspective. The author believes that trade surplus and savings surplus are not the absolute metrics to define a country’s economic strength. China’s balance of payments has continued to maintain a big surplus, which shows China’s unique economic structure and growth model and exposes deep contradictions in income distribution, factor prices and resource allocation. While stimulating rapid growth, the imbalance of China’s economy, at the same time, has long delayed the upgrading of industrial structure, aggravating the threat of inflation and heightening concerns of an asset bubble. Although the external and internal imbalances are closely linked to each other, they are quite different in nature. This similar global economic imbalance has existed for a long time, and to a great extent, is inevitable and rational. However, internal imbalances caused by its own systems and policies, if lasted, would have severe and negative impacts not only on China’s economy, but on the global economy as a whole.
文摘Muscle imbalances are a well accepted cause of musculo-skeletal pain, yet clinicians lack a simple, non-invasive, and reproducible means to assess muscle effort during activities of daily living. To address this issue, we have been developing vibromyography (VMG) as a means to quantitatively assess muscle mechanical effort such that accurate muscle effort ratios can be determined in the clinic. In this study, VMG was used to characterize muscle imbalances in older adults with low-level knee pain while they performed step-up and step-down activities. In addition to determining whether VMG can identify the imbalances previously reported in individuals with knee pain, we address the question of whether these knee muscle imbalances were a likely cause of knee pain, or whether the imbalances represented a coping response for pre-existing knee pain. A population (N = 30) of 35 - 85 year old men and women with a total of 42 painful knees were assessed. Robust multiple step-wise regression analysis identified weak hip abductor muscle effort relative to hamstring muscle effort as the best predictor of knee pain (p = 0.00006), with weak vastus lateralis effort in eccentric contraction, relative to concentric contraction, being the second best predictor (p = 0.0003). Muscle imbalances were able to account for 40% of the variation in reported pain, and the observed pattern of increasing knee pain with increasing quadriceps strength during concentric contraction leads us to infer that the observed muscle imbalances are not the result of a protective action by the individual, but rather are a principle cause of the knee pain.
基金the final result of the “Tsinghua China Balanced Development Index” Project of the China Data CenterTsinghua University+1 种基金Sponsored by the Minshan Public-Interest Fund of the China Siyuan Foundation for Poverty Alleviation (CSFPA) with special sponsorship from the China Post-Doctoral Science Foundation (2018T110079)general sponsorship from the China Post-Doctoral Science Foundation (2017M620719)。
文摘The principal contradiction facing the Chinese society has evolved to be that between imbalanced and inadequate development and the people’s ever-growing needs for a better life.Given China’s vision for achieving moderate prosperity,it is relevant to conduct theoretical and empirical studies on the nation’s development imbalances.As a quantitative index,the Tsinghua China Balanced Development Index measures the extent to which development is uneven and insuf ficient across regions,re flecting the progress and shortfalls in China’s efforts to promote balanced development.Our findings provide implications for how policymakers may help people’s expectations for a better life materialize by spurring balanced economic,social,environmental and livelihood development across regions.
文摘Despite all of the many discrepancies and contradictions in the estimate of the water balance in the Barada Awaj basin, all the research and reports, both local and international, indicate that the basin suffers from water depletion. The agricultural sector is the largest consumer of water, and the area of land irrigated by the basin has risen significantly. Rapid population growth as a result of natural increase and massive immigration to the basin, piratical well-digging without permits, the failure to increase the area of land irrigated by modern methods and a decrease in rainfall and the drought that has affected Syria in general and the Barada Awaj basin in particular, have led to a water shortage in the basin during the first decade of this century.
基金This research is supported by: National Social Science Foundation " Study on China's imbalanced foreign trade from the perspective of intra-product specialization" (10BJY079).
文摘Demographic transitions occur at different times and speed across different economies, and age structures consequently differ across regions. Using a solvable four-phase model, we show that economies with a higher proportion of working-age force and a lower dependency ratio tend to have higher savings rates. Because the demographic " center of gravity"for investment demand falls at a younger point in the age distribution than that of savings supply, countries with a younger age-distribution like those described above generate national savings in excess of domestic investment, resulting in a current account surplus. Numerical simulation supports this hypothesis. But the relative youth or age of a country's population reflects temporary demographic trends which change continuously. Therefore, while trade imbalances caused by demographic factors are structural and long-term, they are not permanent, and may be reversed by changes in age structure.
文摘The seasonal changes in the energy balance after the substitution of a herbaceous savanna by a Brachiaria field located in the Orinoco lowlands were assessed over an entire year using the eddy covariance technique. Simultaneously, an herbaceous savanna was monitored as a control. This work provides evidence that the vegetation replacement lead to different patterns of energy and water balance. The seasonal trends of the latent heat flux (λE) to available energy (Ra) ratio tended to decrease as senescence increased due to seasonal influence of air humidity mole fraction deficit and soil water content on leaf area index (LAI) and surface conductance (gs). Therefore, the partitioning of the available energy depended on both climatological (i.e., solar radiation, volumetric soil water content and air humidity mole fraction deficit) and biological variables (i.e., conductance behavior and LAI) which were stress-induced. For the wet season, the seasonally averaged daily λE in the Brachiaria field (i.e., 0.8 ± 0.1 mm d^-1) was 1.3-fold higher than that in the herbaceous savanna (i.e., 0.6 ± 0.1 mm d-1)(Mann-Whitney U-test). For the dry season, the value was 2.7 ± 0.6 and 2.2 ± 0.4 mm d-1, respectively, these means values were not significantly different. In the Brachiaria and herbaceous savanna stands, the annual evapotranspiration was 731 and 594 mm year^-1, respectively, and the annual ratio of evapotranspiration to precipitation was 0.52 to 0.42 respectively. In Brachiaria field, the deep drainage was relatively lower (43% of total precipitation) than that in the herbaceous savanna stand (53%) leaving a similar amount of water to increase soil storage. The current shift in land cover decrease deep drainage and increased λE by water uptake from a pasture with high belowground phytomass and LAI.
文摘Looking back at over a decade of research by herself and her group,the author advocates the added value of gas phase measurements and the application of mass balances,as well as the synergetic benefits obtained when combining both.The increased application of off-gas measurements for greenhouse gas emission monitoring offers a great opportunity to look at other components in the gas phase,particularly oxygen.Mass balances should not be strictly reserved for modellers but also prove useful while conducting lab experiments and studying full-scale measurement data.Combining off-gas measurements with mass balances may serve not only to quantify greenhouse gas emission factors and aeration efficiency but also to follow dynamic concentration profiles of dissolved components without dedicated sensors and/or to calculate other unmeasured variables.Mass-balance-based data reconciliation allows for obtaining reliable and accurate data,and even more when combined with off-gas analysis.
文摘This study, which assesses the quality of soils under cocoa trees in the Marahoué region of Côte d’Ivoire, is being carried out against a backdrop of declining crop yields due to a number of factors, including the loss of soil fertility. The aim was to identify homogeneous groups of soils in terms of fertility and propose sustainable management methods for each group. The study was carried out on twenty-four cocoa orchards belonging to the SCOOP KAPATCHIVA cooperative, spread over eight sectors. A morphological characterisation of the soils was carried out in the field, followed by physico-chemical laboratory analyses of soil samples taken in the field. Soil fertility was analyzed on the basis of these two groups of data. The results showed that soil depths were generally high, except in some high altitude areas, where soils were often enriched in ferromagnesian elements and compacted. The texture of the soils varied between loamy and sandy-loamy, influencing cocoa production. Indeed, the soils of the plots with high production were looser and without ferromagnesian concretions, while those of the plots with low production were more gravelly and compact. Biological activity in the upper soil layer (0 - 30 cm) was notable with an abundance of termites and earthworms. The organic matter and nitrogen content varies considerably between sectors, directly impacting soil fertility. The soils were slightly acidic and showed significant differences in the levels of exchangeable magnesium and potassium, and not at all for phosphorus which appeared at very low doses. Chemical analysis also revealed that nutrient balance was a key factor in orchard productivity, with varying ratios of calcium, magnesium and potassium. Knowledge of these results made it possible to make recommendations for soil management with a view to improving cocoa yields in the study area.
文摘Phosphorus bioavailability has long been a recurring problem in tropical acid soils. A pot experiment was carried out during three (3) successive rice production cycles at Adiopodoumé to evaluate the response of the NERICA 5 rice accession to various doses of calcium, magnesium and phosphorous. The experiment was conducted using a randomized split-plot design. The interactive effects of calcium carbonate (0, 25, 50 and 75 kg·Ca·ha<sup>-1</sup>) and magnesium sulfate (0, 25, 50 and 75 kg·Mg·ha<sup>-1</sup>) and Togo natural phosphate (0, 25, 50 and 75 kg·P·ha<sup>-1</sup>) were determined at each production cycle. The results showed that single-dose natural phosphate supplementation for three cropping cycles resulted in an average enrichment of around 2 mg·P·kg<sup>-1</sup> after each trial following its continuous dissolution, with an increase in DSP (33.31% to 70.52%). The study revealed one strategy for managing and enhancing native P with cations and another for exogenous P: there would be a synergy of Ca/Mg on native P, whereas an antagonism would characterize the two parameters in phosphate fertilization.
基金supported by the National Natural Science Foundation of China,No.82173800 (to JB)Shenzhen Science and Technology Program,No.KQTD20200820113040070 (to JB)。
文摘Na^(+)/K^(+)-ATPase is a transmembrane protein that has important roles in the maintenance of electrochemical gradients across cell membranes by transporting three Na^(+)out of and two K^(+)into cells.Additionally,Na^(+)/K^(+)-ATPase participates in Ca^(2+)-signaling transduction and neurotransmitter release by coordinating the ion concentration gradient across the cell membrane.Na^(+)/K^(+)-ATPase works synergistically with multiple ion channels in the cell membrane to form a dynamic network of ion homeostatic regulation and affects cellular communication by regulating chemical signals and the ion balance among different types of cells.Therefo re,it is not surprising that Na^(+)/K^(+)-ATPase dysfunction has emerged as a risk factor for a variety of neurological diseases.However,published studies have so far only elucidated the important roles of Na^(+)/K^(+)-ATPase dysfunction in disease development,and we are lacking detailed mechanisms to clarify how Na^(+)/K^(+)-ATPase affects cell function.Our recent studies revealed that membrane loss of Na^(+)/K^(+)-ATPase is a key mechanism in many neurological disorders,particularly stroke and Parkinson's disease.Stabilization of plasma membrane Na^(+)/K^(+)-ATPase with an antibody is a novel strategy to treat these diseases.For this reason,Na^(+)/K^(+)-ATPase acts not only as a simple ion pump but also as a sensor/regulator or cytoprotective protein,participating in signal transduction such as neuronal autophagy and apoptosis,and glial cell migration.Thus,the present review attempts to summarize the novel biological functions of Na^(+)/K^(+)-ATPase and Na^(+)/K^(+)-ATPase-related pathogenesis.The potential for novel strategies to treat Na^(+)/K^(+)-ATPase-related brain diseases will also be discussed.
基金supported by the National Natural Science Foundation of China (Grant No. 41888101)。
文摘One of the basic characteristics of Earth's modern climate is that the Northern Hemisphere(NH) is climatologically warmer than the Southern Hemisphere(SH). Here, model performances of this basic state are examined using simulation results from 26 CMIP6 models. Results show that the CMIP6 models underestimate the contrast in interhemispheric surface temperatures on average(0.8 K for CMIP6 mean versus 1.4 K for reanalysis data mean), and that there is a large intermodel spread, ranging from -0.7 K to 2.3 K. A box model energy budget analysis shows that the contrast in interhemispheric shortwave absorption at the top of the atmosphere, the contrast in interhemispheric greenhouse trapping, and the crossequatorial northward ocean heat transport, are all underestimated in the multimodel mean. By examining the intermodel spread, we find intermodel biases can be tracked back to biases in midlatitude shortwave cloud forcing in AGCMs. Models with a weaker interhemispheric temperature contrast underestimate the shortwave cloud reflection in the SH but overestimate the shortwave cloud reflection in the NH, which are respectively due to underestimation of the cloud fraction over the SH extratropical ocean and overestimation of the cloud liquid water content over the NH extratropical continents.Models that underestimate the interhemispheric temperature contrast exhibit larger double ITCZ biases, characterized by excessive precipitation in the SH tropics. Although this intermodel spread does not account for the multimodel ensemble mean biases, it highlights that improving cloud simulation in AGCMs is essential for simulating the climate realistically in coupled models.