The photo-Fenton reaction is a key source of the highly reactive hydroxyl radical（HOU） that is produced by the reaction of simultaneous photo-induced generation of Fe^（2＋）-dissolved organic matter（DOM） with H_2...The photo-Fenton reaction is a key source of the highly reactive hydroxyl radical（HOU） that is produced by the reaction of simultaneous photo-induced generation of Fe^（2＋）-dissolved organic matter（DOM） with H_2O_2 in sunlit surface waters as well as in the treatment of organic pollutants in the advanced oxidation processes（AOPs）.Concentrations of both H_2O_2 and Fe^（2＋）-DOM were dependent on time and total solar intensity flux,and their levels were highest in the diurnal samples collected at noon compared with the samples collected during the period before sunrise and after sunset.H_2O_2 and Fe^（2＋）-DOM concentrations during monthly readings were also found higher in comparison with the diurnal samples,shortly before sunrise or after sunset.A π-electron bonding system is formed between Fe and the functional groups in DOM（Fe-DOM）,through electron donation from the functional groups of DOM to an empty d-orbital of Fe.The π-electron is loosely bound and is highly susceptible to a rapid excitation upon light exposure that will provide better understanding of the formation of aqueous electrons,superoxide radical anions,H_2O_2 and finally,photo-Fenton reactions,too.Our results imply that simultaneous generation of H_2O_2 and Fe^（2＋）-DOM upon sunlight exposure during the daytime is most likely to be the key photo-Fenton reaction pathway,taking place in surface waters.展开更多
This study addresses the hypothesis that stagnation of soybean yield on the farm can be improved by selection of a physiological trait favoring carbon assimilate partitioning to terminally placed pods versus genotypes...This study addresses the hypothesis that stagnation of soybean yield on the farm can be improved by selection of a physiological trait favoring carbon assimilate partitioning to terminally placed pods versus genotypes having axillary pods at close plant spacing.13C was fed to source-sink units comprising a leaf,axillary/terminal pods,and petioles at upper and lower positions of the stem axis in two soybean cultivars,namely Shakujo and Enrei,at different densities of populations.The cultivars differ significantly in architecture,Shakujo bearing a few hundreds of pods in close succession to one another in a terminally placed raceme,in contrast to Enrei having axillary racemes.Pod yield per plant was higher in Enrei than in Shakujo at low density,but Shakujo out-yielded Enrei at close spacing.Population density decreased yield per plant and altered the pattern of assimilate partitioning significantly within the plants for both varieties.At high density more assimilates moved to the upper parts at the cost of the lower parts.The terminally placed pods of Shakujo were advantaged to receive assimilates under density stress.No benefit was accrued to pod filling of Enrei,however,under this condition.展开更多
This study compares the performance of three fire risk indices for accuracy in predicting fires in semideciduous forest fragments,creates a fire risk map by integrating historical fire occurrences in a probabilistic d...This study compares the performance of three fire risk indices for accuracy in predicting fires in semideciduous forest fragments,creates a fire risk map by integrating historical fire occurrences in a probabilistic density surface using the Kernel density estimator(KDE)in the municipality of Sorocaba,Sao Paulo state,Brazil.The logarithmic Telicyn index,Monte Alegre formula(MAF)and enhanced Monte Alegre formula(MAF+)were employed using data for the period 1 January 2005 to 31 December 2016.Meteorological data and numbers of fire occurrences were obtained from the National Institute of Meteorology(INMET)and the Institute for Space Research(INPE),respectively.Two performance measures were calculated:Heidke skill score(SS)and success rate(SR).The MAF+index was the most accurate,with values of SS and SR of 0.611%and 62.8%,respectively.The fire risk map revealed two most susceptible areas with high(63 km^2)and very high(47 km^2)risk of fires in the municipality.Identification of the best risk index and the generation of fire risk maps can contribute to better planning and cost reduction in preventing and fighting forest fires.展开更多
This study presents a post-remediation assessment of soil quality at the Olero-Abiteye oil spill corridor in the Niger Delta,following intervention via evacu-ation and Enhanced Natural Attenuation(ENA)techniques.The i...This study presents a post-remediation assessment of soil quality at the Olero-Abiteye oil spill corridor in the Niger Delta,following intervention via evacu-ation and Enhanced Natural Attenuation(ENA)techniques.The investigation evaluates the persistence and interactions of Total Petroleum Hydrocarbons(TPH)and heavy metals across two soil depths(0-15 cm and 15-30 cm)and two seasons(wet and dry),in comparison with control samples.Results indi-cate that TPH concentrations remain significantly elevated across all sampled horizons,with dry season surface soils recording 3945.14±1342.22 mg/kg—well below the EGASPIN intervention threshold of 5000 mg/kg.Heavy metals,notably copper(Cu),also exceeded permissible limits in all depths and sea-sons,with Risk Quotients(RQ)consistently greater than 1.0.Multivariate analyses reveal strong correlations(r>0.75,p<0.01)between TPH,Cu,Pb,and Total Organic Content(TOC),suggesting synergistic sorption mecha-nisms that hinder contaminant mobility but also prolong environmental per-sistence.Principal Component Analysis(PCA)and Hierarchical Cluster Anal-ysis(HCA)further highlight the seasonal and depth-based stratification of pollutants,driven by hydrological and physicochemical dynamics.These find-ings demonstrate that current remediation methods,while partially effective,fall short of fully restoring ecological integrity,particularly within organic-rich surface soils.The study underscores the need for integrated,depth-targeted,and seasonally adaptive remediation strategies to address the coupled behav-iour of hydrocarbons and heavy metals in tropical oil-impacted landscapes.Post-remediation monitoring and enhanced contaminant-specific interven-tions are recommended to ensure sustainable recovery and land reuse.展开更多
This study investigates the impacts of deforestation within the influence area of the BR-319 highway on local climate conditions following its planned reconstruction.High-resolution climate modeling indicates that mea...This study investigates the impacts of deforestation within the influence area of the BR-319 highway on local climate conditions following its planned reconstruction.High-resolution climate modeling indicates that mean air temperature may increase by up to 0.7℃under the paved-road scenario(BAU_2)by 2100,with local increases exceeding 2.5℃in deforested regions during the dry season.Precipitation is projected to rise by an average of up to 0.5 mm·day^(-1),with local increases above 2.5 mm·day^(-1)in fragmented landscapes.However,this effect is likely temporary and may shift to declining rainfall as deforestation consolidates into large continuous areas.These effects are driven by reduced evapotranspiration,increased surface temperatures,and changes in atmospheric circulation patterns.Such alterations result in greater moisture convergence over deforested zones,thereby influencing the regional hydrological cycle.The comparison of different deforestation scenarios underscores the significant influence of highway development on local climate.The results highlight the importance of incorporating climate projections into environmental assessments to inform public policy decisions regarding infrastructure projects in the Amazon.展开更多
基金the Japan Society for the Promotion of Science for the financial support through a Grant-in-Aid for Scientific Research (B) (No.18310010)partly supported by the Key Construction Program of the National "985" Project,Tianjin University,China
文摘The photo-Fenton reaction is a key source of the highly reactive hydroxyl radical（HOU） that is produced by the reaction of simultaneous photo-induced generation of Fe^（2＋）-dissolved organic matter（DOM） with H_2O_2 in sunlit surface waters as well as in the treatment of organic pollutants in the advanced oxidation processes（AOPs）.Concentrations of both H_2O_2 and Fe^（2＋）-DOM were dependent on time and total solar intensity flux,and their levels were highest in the diurnal samples collected at noon compared with the samples collected during the period before sunrise and after sunset.H_2O_2 and Fe^（2＋）-DOM concentrations during monthly readings were also found higher in comparison with the diurnal samples,shortly before sunrise or after sunset.A π-electron bonding system is formed between Fe and the functional groups in DOM（Fe-DOM）,through electron donation from the functional groups of DOM to an empty d-orbital of Fe.The π-electron is loosely bound and is highly susceptible to a rapid excitation upon light exposure that will provide better understanding of the formation of aqueous electrons,superoxide radical anions,H_2O_2 and finally,photo-Fenton reactions,too.Our results imply that simultaneous generation of H_2O_2 and Fe^（2＋）-DOM upon sunlight exposure during the daytime is most likely to be the key photo-Fenton reaction pathway,taking place in surface waters.
文摘This study addresses the hypothesis that stagnation of soybean yield on the farm can be improved by selection of a physiological trait favoring carbon assimilate partitioning to terminally placed pods versus genotypes having axillary pods at close plant spacing.13C was fed to source-sink units comprising a leaf,axillary/terminal pods,and petioles at upper and lower positions of the stem axis in two soybean cultivars,namely Shakujo and Enrei,at different densities of populations.The cultivars differ significantly in architecture,Shakujo bearing a few hundreds of pods in close succession to one another in a terminally placed raceme,in contrast to Enrei having axillary racemes.Pod yield per plant was higher in Enrei than in Shakujo at low density,but Shakujo out-yielded Enrei at close spacing.Population density decreased yield per plant and altered the pattern of assimilate partitioning significantly within the plants for both varieties.At high density more assimilates moved to the upper parts at the cost of the lower parts.The terminally placed pods of Shakujo were advantaged to receive assimilates under density stress.No benefit was accrued to pod filling of Enrei,however,under this condition.
文摘This study compares the performance of three fire risk indices for accuracy in predicting fires in semideciduous forest fragments,creates a fire risk map by integrating historical fire occurrences in a probabilistic density surface using the Kernel density estimator(KDE)in the municipality of Sorocaba,Sao Paulo state,Brazil.The logarithmic Telicyn index,Monte Alegre formula(MAF)and enhanced Monte Alegre formula(MAF+)were employed using data for the period 1 January 2005 to 31 December 2016.Meteorological data and numbers of fire occurrences were obtained from the National Institute of Meteorology(INMET)and the Institute for Space Research(INPE),respectively.Two performance measures were calculated:Heidke skill score(SS)and success rate(SR).The MAF+index was the most accurate,with values of SS and SR of 0.611%and 62.8%,respectively.The fire risk map revealed two most susceptible areas with high(63 km^2)and very high(47 km^2)risk of fires in the municipality.Identification of the best risk index and the generation of fire risk maps can contribute to better planning and cost reduction in preventing and fighting forest fires.
文摘This study presents a post-remediation assessment of soil quality at the Olero-Abiteye oil spill corridor in the Niger Delta,following intervention via evacu-ation and Enhanced Natural Attenuation(ENA)techniques.The investigation evaluates the persistence and interactions of Total Petroleum Hydrocarbons(TPH)and heavy metals across two soil depths(0-15 cm and 15-30 cm)and two seasons(wet and dry),in comparison with control samples.Results indi-cate that TPH concentrations remain significantly elevated across all sampled horizons,with dry season surface soils recording 3945.14±1342.22 mg/kg—well below the EGASPIN intervention threshold of 5000 mg/kg.Heavy metals,notably copper(Cu),also exceeded permissible limits in all depths and sea-sons,with Risk Quotients(RQ)consistently greater than 1.0.Multivariate analyses reveal strong correlations(r>0.75,p<0.01)between TPH,Cu,Pb,and Total Organic Content(TOC),suggesting synergistic sorption mecha-nisms that hinder contaminant mobility but also prolong environmental per-sistence.Principal Component Analysis(PCA)and Hierarchical Cluster Anal-ysis(HCA)further highlight the seasonal and depth-based stratification of pollutants,driven by hydrological and physicochemical dynamics.These find-ings demonstrate that current remediation methods,while partially effective,fall short of fully restoring ecological integrity,particularly within organic-rich surface soils.The study underscores the need for integrated,depth-targeted,and seasonally adaptive remediation strategies to address the coupled behav-iour of hydrocarbons and heavy metals in tropical oil-impacted landscapes.Post-remediation monitoring and enhanced contaminant-specific interven-tions are recommended to ensure sustainable recovery and land reuse.
基金Support Foundation(FAPEAM)(Resolution 003/2019,01.02.016301.02529/2024-87)the Coordination for the Improvement of Higher Education Personnel(CAPES)(Finance Code 001),for institutional support+2 种基金the Brazilian Institute of the Environment and Renewable Natural Resources(IBAMA)for its supportthe National Council for Scientific and Technological Development(CNPq 312450/2021-4,406941/2022-0)the Brazilian Research Network on Climate Change(Rede Clima)(FINEP/Rede Clima 01.13.0353-00).
文摘This study investigates the impacts of deforestation within the influence area of the BR-319 highway on local climate conditions following its planned reconstruction.High-resolution climate modeling indicates that mean air temperature may increase by up to 0.7℃under the paved-road scenario(BAU_2)by 2100,with local increases exceeding 2.5℃in deforested regions during the dry season.Precipitation is projected to rise by an average of up to 0.5 mm·day^(-1),with local increases above 2.5 mm·day^(-1)in fragmented landscapes.However,this effect is likely temporary and may shift to declining rainfall as deforestation consolidates into large continuous areas.These effects are driven by reduced evapotranspiration,increased surface temperatures,and changes in atmospheric circulation patterns.Such alterations result in greater moisture convergence over deforested zones,thereby influencing the regional hydrological cycle.The comparison of different deforestation scenarios underscores the significant influence of highway development on local climate.The results highlight the importance of incorporating climate projections into environmental assessments to inform public policy decisions regarding infrastructure projects in the Amazon.
