Reed pans are a very uncommon type of endorheic wetland, and as such the amount of information available is very limited. Thus, they are being impacted on by various agricultural, livestock and other anthropogenic act...Reed pans are a very uncommon type of endorheic wetland, and as such the amount of information available is very limited. Thus, they are being impacted on by various agricultural, livestock and other anthropogenic activities. The objectives of this study were to determine the spatial and temporal variations of macroinvertebrate community structures in reed pans and the environmental factors (i.e., water quality) responsible for the maintenance of these structures. Reed pans were studied over four different seasons, during which time subsurface water, sediment and macroinvertebrate samples were collected and analyzed. The reed pans studied showed that the macroinvertebrates were able to reflect various changes in reed pans with regard to seasonal variability and anthropogenic impacts on water quality. These anthropogenic impacts caused the disappearance of sensitive macroinvertebrate taxa and the increase of tolerant macroinvertebrate taxa.展开更多
This study demonstrated the potential of single chamber up-flow membrane-less microbial fuel cell（UFML-MFC） in wastewater treatment and power generation. The purpose of this study was to evaluate and enhance the per...This study demonstrated the potential of single chamber up-flow membrane-less microbial fuel cell（UFML-MFC） in wastewater treatment and power generation. The purpose of this study was to evaluate and enhance the performance under different operational conditions which affect the chemical oxygen demand（COD） reduction and power generation,including the increase of KCl concentration（MFC1） and COD concentration（MFC2）. The results showed that the increase of KCl concentration is an important factor in up-flow membrane-less MFC to enhance the ease of electron transfer from anode to cathode. The increase of COD concentration in MFC2 could led to the drop of voltage output due to the prompt of biofilm growth in MFC2 cathode which could increase the internal resistance. It also showed that the COD concentration is a vital issue in up-flow membrane-less MFC.Despite the COD reduction was up to 96%, the power output remained constrained.展开更多
Tailing ponds pose environmental hazards, such as toxic metals which can contaminate the surroundings through wind and water erosions and leaching. Various chemical and biochemical properties, together with extractabl...Tailing ponds pose environmental hazards, such as toxic metals which can contaminate the surroundings through wind and water erosions and leaching. Various chemical and biochemical properties, together with extractable and soluble metals were measured five years after reclamation of a polluted soil affected by former mining activities. This abandoned mine site contains large amounts of Fe-oxyhydroxides, sulphates, and heavy metals. As a consequence, soils remain bare and the soil organic matter content is low （〈 3 g kg-1）. Marble waste, pig manure and sewage sludge were applied in 2004. Plant cover and richness, and soil chemical, biochemical and biological parameters were analysed five years later. Results showed that all soil biochemical properties as well as vegetation cover and richness were higher in treated soils than in the untreated contaminated plots （control）, although organic matter, pH values and extractable metals concentrations were similar among treatments. Soluble cadmium and zinc were lower in the amended plots than in control.展开更多
This paper is aimed at examining the applicability of methods for resilience, reliability and risk analyses of rain-fed agricultural systems from modeled continuous soil moisture availability in rain-fed crop lands. T...This paper is aimed at examining the applicability of methods for resilience, reliability and risk analyses of rain-fed agricultural systems from modeled continuous soil moisture availability in rain-fed crop lands. The methodology involves integration of soil and climatic data in a simple soil moisture accounting model to assess soil moisture availability, and a risk used as indicator of sustainability of rain-fed agricultural systems. It is also attempted to demonstrate the role of soil moisture modeling in risk analysis and agricultural water management in a semi-arid region in Limpopo Basin where rain-fed agriculture is practiced. For this purpose, a daily-time step soil moisture accounting model is employed to simulate daily soil moisture, evaporation, surface runoff, and deep percolation using 40 years (1961-2000) of agroclimatic data, and cropping cycle data of maize, sorghum and sunflower. Using a sustainability criterion on crop water requirement and soil moisture availability, we determined resilience, risk and reliability as a quantitative measure of sustainability of rain-fed agriculture of these three crops. These soil moisture simulations and the sustainability criteria revealed further confirmation of the relative sensitivity to drought of these crops. Generally it is found that the risk of failure is relatively low for sorghum and relatively high for maize and sunflower in the two sites with some differences of severity of failure owing to the slightly different agroclimatic settings.展开更多
As the dominant macrofauna in many soils,earthworms play a significant role in mineral weathering and nutrient release from mineral structures into available forms for root uptake.Phlogopite is a trioctahedral micaceo...As the dominant macrofauna in many soils,earthworms play a significant role in mineral weathering and nutrient release from mineral structures into available forms for root uptake.Phlogopite is a trioctahedral micaceous mineral that can be weathered to other minerals through release of its interlayer potassium(K).In this study,we investigated the effect of earthworm activities and associated microbial communities on phlogopite weathering during the production of phlogopite-enriched vermicompost with different quantities of phlogopite added.An experiment was run under laboratory conditions using three levels of phlogopite(0,20%and 40%by weight)in triplicates.Each Petri dish contained 20 g of a mixture of cow manure and phlogopite,and vermicomposting process was performed by inoculation of eight Eisenia foetida earthworms.Changes in clay mineralogy and C/N ratio in each dish were assessed at days 0,45,90,135,and 180 during vermicomposting.The results indicated that phlogopite was partially weathered to vermiculite and interstratified mica-vermiculite during the vermicomposting process.The rate of weathering was higher during the early stages of vermicomposting(the first 90 d).The weathering of phlogopite was influenced considerably by the activity of earthworms and associated microbial communities during the organic matter transformation process.At the early stages of the process,the weathering rate for different levels of phlogopite was not significantly different,but over time it accelerated steadily,and the difference increased.展开更多
Composites of montmorillonite clay and sawdust were prepared with the desired result being having new materials which burn longer than unmodified sawdust. The three forms of clay used for preparation of composites wer...Composites of montmorillonite clay and sawdust were prepared with the desired result being having new materials which burn longer than unmodified sawdust. The three forms of clay used for preparation of composites were unmodified montmorillonite, mono-ionic montmorillonite and organically modified montmorillonite. Montmorillonite clay was converted to mono-ionic clay by ion exchange with sodium using a sodium chloride solution. The mono-ionic clay was organically modified with an organic surfactant, methyl triphenyl phosphonium bromide. Nanocomposites were then prepared by combining the modified and raw forms of the clay with sawdust. The solution blending method was used to make the nanocomposites. The samples were analysed using thermogravimetric analysis and cone calorimetry. The studies showed that the nanocomposite which was made from sawdust and 1% organically modified clay had the most improved results in terms of burning time and thermal stability, as well as giving a calorific value closest to unmodified sawdust and the least amount of residue.展开更多
Andean grasslands ecosystems are fragile environments with rigorous climatologic conditions and low and variable food for the grazing. The Apolobamba area is located in the Bolivian Andean Mountains. Its high grasslan...Andean grasslands ecosystems are fragile environments with rigorous climatologic conditions and low and variable food for the grazing. The Apolobamba area is located in the Bolivian Andean Mountains. Its high grasslands provide a natural habitat for wild and domestic camelids such as vicuna(Vicugna vicugna) and alpaca(Lama pacos). The botanical diversity plays an essential role in maintaining vital ecosystem functions. The objectives of this research were to determine the seasonal changes in soil properties, to study the vegetation changes during the wet and dry seasons and the influence of soil properties and camelid densities on the vegetation in the Apolobamba grasslands. Four zones with different vicuna populations were selected to be studied. The following soil parameters were determined: total organic carbon, total nitrogen, available phosphorous, cation exchange capacity, exchangeable cations, pH and texture. The vegetation season changes were studied through botanical identification, above-ground biomass, plant cover and species richness. Results showed that some soil properties such as C/N ratio, CEC, silt and clay percentages kept stable against the seasonal changes. Generally, soil nutrients were relatively higher during the dry season in the surface and subsurface. The results did not point out the predominant vegetation growth during the wet season. The seasonal vegetation growth depended on each species. Thegood soil fertility corresponded to the highest plant cover. Soil fertility presented no influence on the above-ground biomass of the collected species. The negative influence of camelid grazing on soil properties could not be assessed. However, overgrazing could affect some plant species. Therefore, protection is needed in order to preserve the biodiversity in the Andean mountain grasslands.展开更多
Purpose This study compared the acute effects of a session of isometric strength training(ISO)with heavy resistance training(HRT)training on 20-m sprint,countermovement jump(CMJ)and isometric mid-thigh pull(IMTP)perfo...Purpose This study compared the acute effects of a session of isometric strength training(ISO)with heavy resistance training(HRT)training on 20-m sprint,countermovement jump(CMJ)and isometric mid-thigh pull(IMTP)performance.Methods Ten resistance-trained athletes(age:26.7±6.2 years,body mass:71.5±16.2 kg,height:1.68±0.10 m)performed baseline measures for 20-m sprint,CMJ and IMTP prior to either an ISO or HRT session.During both training sessions,participants performed back squats,Romanian deadlift and split squat.Post-test performances were measured 5 min and 24 h after each training session.Participants returned a week later to perform the other training session.Results A significant time×condition effect was found for 20-m sprint time(P=0.007)and IMTP peak force(P=0.003).Main time effect was observed for 20-m sprint(P<0.001),CMJ height(P<0.001)and IMTP peak force(P<0.001).HRT resulted in a greater increase in sprint time at 5 min(0.17±0.12 vs.0.06±0.05 s,P=0.013,g=1.15)and 24 h(0.01±0.09 vs.0.00±0.05 s,P=0.004,g=1.32)post-training as compared to ISO.Similarly,HRT resulted in a significantly larger reduction in IMTP peak force than ISO at both 5 min(-363.3±248.8 vs.-98.9±230.3 N,P=0.024,g=1.06)and 24 h(-289.2±256.2 vs.37.9±177.8 N,P=0.004,g=1.42)post-training.Total impulses generated during each exercise were greater during ISO than HRT(P<0.001–0.006).Rating of perceived recovery post 24 h was higher in ISO than HRT(P=0.002).Conclusion The above results indicated that acute HRT led to a greater reduction in sprinting strength performance and lower perceived recovery post-24 h than ISO.展开更多
The addition of traditional carbon sources(e.g.,acetate)could favor heterotrophic overgrowth in partial denitrification coupled with anammox(PD–A)systems,thus hindering the performance and stability of this novel was...The addition of traditional carbon sources(e.g.,acetate)could favor heterotrophic overgrowth in partial denitrification coupled with anammox(PD–A)systems,thus hindering the performance and stability of this novel wastewater nitrogen removal technology.Therefore,it is necessary to develop an effective,environmentally friendly,and inexpensive alternative.This study demonstrated the potential of formate to enhance the performance and community stability of PD–A under mainstream conditions.In a laboratory-scale biofilm reactor,formate addition(COD/NO_(3)^(–)–N=1.75)improved nitrogen removal efficiency(from 72.1±3.5%to 81.7±2.7%),EPS content(from 106.3±8.1 to 163.0±15.5 mg/gVSS)and increased anammox bacteria growth(predominantly Candidatus Brocadia,from 29.5±0.7%to 34.5±5.4%)while maintaining stable heterotrophs dominated by methylotrophic Desulfobacillus.FISH–NanoSIMS revealed a formate uptake using Ca.Brocadia and Desulfobacillus,with Ca.Brocadia being the major contributor to partial nitrate reduction to nitrite.Desulfobacillus can synthesize diverse hydrophobic amino acids and provide key nutrients for Ca.Brocadia.To achieve comparable nitrogen removal,the cost of the formate-driven PD–A process should be 11.2%lower than that of acetate.These results greatly enrich our understanding of C1 metabolism represented by formate in anammox communities and its application in the context of coupling partial denitrification–anammox toward enhanced nitrogen removal in global wastewater treatment systems.展开更多
文摘Reed pans are a very uncommon type of endorheic wetland, and as such the amount of information available is very limited. Thus, they are being impacted on by various agricultural, livestock and other anthropogenic activities. The objectives of this study were to determine the spatial and temporal variations of macroinvertebrate community structures in reed pans and the environmental factors (i.e., water quality) responsible for the maintenance of these structures. Reed pans were studied over four different seasons, during which time subsurface water, sediment and macroinvertebrate samples were collected and analyzed. The reed pans studied showed that the macroinvertebrates were able to reflect various changes in reed pans with regard to seasonal variability and anthropogenic impacts on water quality. These anthropogenic impacts caused the disappearance of sensitive macroinvertebrate taxa and the increase of tolerant macroinvertebrate taxa.
基金the Science Fund MOSTI Grant (02-01-15-SF0201) for their support on this study
文摘This study demonstrated the potential of single chamber up-flow membrane-less microbial fuel cell（UFML-MFC） in wastewater treatment and power generation. The purpose of this study was to evaluate and enhance the performance under different operational conditions which affect the chemical oxygen demand（COD） reduction and power generation,including the increase of KCl concentration（MFC1） and COD concentration（MFC2）. The results showed that the increase of KCl concentration is an important factor in up-flow membrane-less MFC to enhance the ease of electron transfer from anode to cathode. The increase of COD concentration in MFC2 could led to the drop of voltage output due to the prompt of biofilm growth in MFC2 cathode which could increase the internal resistance. It also showed that the COD concentration is a vital issue in up-flow membrane-less MFC.Despite the COD reduction was up to 96%, the power output remained constrained.
基金Supported by the European Union FP7the Ministry of Science and Innovation of the Government of Spain
文摘Tailing ponds pose environmental hazards, such as toxic metals which can contaminate the surroundings through wind and water erosions and leaching. Various chemical and biochemical properties, together with extractable and soluble metals were measured five years after reclamation of a polluted soil affected by former mining activities. This abandoned mine site contains large amounts of Fe-oxyhydroxides, sulphates, and heavy metals. As a consequence, soils remain bare and the soil organic matter content is low （〈 3 g kg-1）. Marble waste, pig manure and sewage sludge were applied in 2004. Plant cover and richness, and soil chemical, biochemical and biological parameters were analysed five years later. Results showed that all soil biochemical properties as well as vegetation cover and richness were higher in treated soils than in the untreated contaminated plots （control）, although organic matter, pH values and extractable metals concentrations were similar among treatments. Soluble cadmium and zinc were lower in the amended plots than in control.
文摘This paper is aimed at examining the applicability of methods for resilience, reliability and risk analyses of rain-fed agricultural systems from modeled continuous soil moisture availability in rain-fed crop lands. The methodology involves integration of soil and climatic data in a simple soil moisture accounting model to assess soil moisture availability, and a risk used as indicator of sustainability of rain-fed agricultural systems. It is also attempted to demonstrate the role of soil moisture modeling in risk analysis and agricultural water management in a semi-arid region in Limpopo Basin where rain-fed agriculture is practiced. For this purpose, a daily-time step soil moisture accounting model is employed to simulate daily soil moisture, evaporation, surface runoff, and deep percolation using 40 years (1961-2000) of agroclimatic data, and cropping cycle data of maize, sorghum and sunflower. Using a sustainability criterion on crop water requirement and soil moisture availability, we determined resilience, risk and reliability as a quantitative measure of sustainability of rain-fed agriculture of these three crops. These soil moisture simulations and the sustainability criteria revealed further confirmation of the relative sensitivity to drought of these crops. Generally it is found that the risk of failure is relatively low for sorghum and relatively high for maize and sunflower in the two sites with some differences of severity of failure owing to the slightly different agroclimatic settings.
基金We would like to thank the Iranian National Science Foundation(No.96002378)for financially supporting this research.
文摘As the dominant macrofauna in many soils,earthworms play a significant role in mineral weathering and nutrient release from mineral structures into available forms for root uptake.Phlogopite is a trioctahedral micaceous mineral that can be weathered to other minerals through release of its interlayer potassium(K).In this study,we investigated the effect of earthworm activities and associated microbial communities on phlogopite weathering during the production of phlogopite-enriched vermicompost with different quantities of phlogopite added.An experiment was run under laboratory conditions using three levels of phlogopite(0,20%and 40%by weight)in triplicates.Each Petri dish contained 20 g of a mixture of cow manure and phlogopite,and vermicomposting process was performed by inoculation of eight Eisenia foetida earthworms.Changes in clay mineralogy and C/N ratio in each dish were assessed at days 0,45,90,135,and 180 during vermicomposting.The results indicated that phlogopite was partially weathered to vermiculite and interstratified mica-vermiculite during the vermicomposting process.The rate of weathering was higher during the early stages of vermicomposting(the first 90 d).The weathering of phlogopite was influenced considerably by the activity of earthworms and associated microbial communities during the organic matter transformation process.At the early stages of the process,the weathering rate for different levels of phlogopite was not significantly different,but over time it accelerated steadily,and the difference increased.
文摘Composites of montmorillonite clay and sawdust were prepared with the desired result being having new materials which burn longer than unmodified sawdust. The three forms of clay used for preparation of composites were unmodified montmorillonite, mono-ionic montmorillonite and organically modified montmorillonite. Montmorillonite clay was converted to mono-ionic clay by ion exchange with sodium using a sodium chloride solution. The mono-ionic clay was organically modified with an organic surfactant, methyl triphenyl phosphonium bromide. Nanocomposites were then prepared by combining the modified and raw forms of the clay with sawdust. The solution blending method was used to make the nanocomposites. The samples were analysed using thermogravimetric analysis and cone calorimetry. The studies showed that the nanocomposite which was made from sawdust and 1% organically modified clay had the most improved results in terms of burning time and thermal stability, as well as giving a calorific value closest to unmodified sawdust and the least amount of residue.
基金the Spanish Agency of Cooperation and Development (AECID)
文摘Andean grasslands ecosystems are fragile environments with rigorous climatologic conditions and low and variable food for the grazing. The Apolobamba area is located in the Bolivian Andean Mountains. Its high grasslands provide a natural habitat for wild and domestic camelids such as vicuna(Vicugna vicugna) and alpaca(Lama pacos). The botanical diversity plays an essential role in maintaining vital ecosystem functions. The objectives of this research were to determine the seasonal changes in soil properties, to study the vegetation changes during the wet and dry seasons and the influence of soil properties and camelid densities on the vegetation in the Apolobamba grasslands. Four zones with different vicuna populations were selected to be studied. The following soil parameters were determined: total organic carbon, total nitrogen, available phosphorous, cation exchange capacity, exchangeable cations, pH and texture. The vegetation season changes were studied through botanical identification, above-ground biomass, plant cover and species richness. Results showed that some soil properties such as C/N ratio, CEC, silt and clay percentages kept stable against the seasonal changes. Generally, soil nutrients were relatively higher during the dry season in the surface and subsurface. The results did not point out the predominant vegetation growth during the wet season. The seasonal vegetation growth depended on each species. Thegood soil fertility corresponded to the highest plant cover. Soil fertility presented no influence on the above-ground biomass of the collected species. The negative influence of camelid grazing on soil properties could not be assessed. However, overgrazing could affect some plant species. Therefore, protection is needed in order to preserve the biodiversity in the Andean mountain grasslands.
文摘Purpose This study compared the acute effects of a session of isometric strength training(ISO)with heavy resistance training(HRT)training on 20-m sprint,countermovement jump(CMJ)and isometric mid-thigh pull(IMTP)performance.Methods Ten resistance-trained athletes(age:26.7±6.2 years,body mass:71.5±16.2 kg,height:1.68±0.10 m)performed baseline measures for 20-m sprint,CMJ and IMTP prior to either an ISO or HRT session.During both training sessions,participants performed back squats,Romanian deadlift and split squat.Post-test performances were measured 5 min and 24 h after each training session.Participants returned a week later to perform the other training session.Results A significant time×condition effect was found for 20-m sprint time(P=0.007)and IMTP peak force(P=0.003).Main time effect was observed for 20-m sprint(P<0.001),CMJ height(P<0.001)and IMTP peak force(P<0.001).HRT resulted in a greater increase in sprint time at 5 min(0.17±0.12 vs.0.06±0.05 s,P=0.013,g=1.15)and 24 h(0.01±0.09 vs.0.00±0.05 s,P=0.004,g=1.32)post-training as compared to ISO.Similarly,HRT resulted in a significantly larger reduction in IMTP peak force than ISO at both 5 min(-363.3±248.8 vs.-98.9±230.3 N,P=0.024,g=1.06)and 24 h(-289.2±256.2 vs.37.9±177.8 N,P=0.004,g=1.42)post-training.Total impulses generated during each exercise were greater during ISO than HRT(P<0.001–0.006).Rating of perceived recovery post 24 h was higher in ISO than HRT(P=0.002).Conclusion The above results indicated that acute HRT led to a greater reduction in sprinting strength performance and lower perceived recovery post-24 h than ISO.
基金funded by the Zhejiang Provincial Natural Science Foundation of China(No.LR23B070002)the General Program of the National Natural Science Foundation of China(No.22276165).
文摘The addition of traditional carbon sources(e.g.,acetate)could favor heterotrophic overgrowth in partial denitrification coupled with anammox(PD–A)systems,thus hindering the performance and stability of this novel wastewater nitrogen removal technology.Therefore,it is necessary to develop an effective,environmentally friendly,and inexpensive alternative.This study demonstrated the potential of formate to enhance the performance and community stability of PD–A under mainstream conditions.In a laboratory-scale biofilm reactor,formate addition(COD/NO_(3)^(–)–N=1.75)improved nitrogen removal efficiency(from 72.1±3.5%to 81.7±2.7%),EPS content(from 106.3±8.1 to 163.0±15.5 mg/gVSS)and increased anammox bacteria growth(predominantly Candidatus Brocadia,from 29.5±0.7%to 34.5±5.4%)while maintaining stable heterotrophs dominated by methylotrophic Desulfobacillus.FISH–NanoSIMS revealed a formate uptake using Ca.Brocadia and Desulfobacillus,with Ca.Brocadia being the major contributor to partial nitrate reduction to nitrite.Desulfobacillus can synthesize diverse hydrophobic amino acids and provide key nutrients for Ca.Brocadia.To achieve comparable nitrogen removal,the cost of the formate-driven PD–A process should be 11.2%lower than that of acetate.These results greatly enrich our understanding of C1 metabolism represented by formate in anammox communities and its application in the context of coupling partial denitrification–anammox toward enhanced nitrogen removal in global wastewater treatment systems.
