For rechargeable wireless sensor networks,limited energy storage capacity,dynamic energy supply,low and dynamic duty cycles cause that it is unpractical to maintain a fixed routing path for packets delivery permanentl...For rechargeable wireless sensor networks,limited energy storage capacity,dynamic energy supply,low and dynamic duty cycles cause that it is unpractical to maintain a fixed routing path for packets delivery permanently from a source to destination in a distributed scenario.Therefore,before data delivery,a sensor has to update its waking schedule continuously and share them to its neighbors,which lead to high energy expenditure for reestablishing path links frequently and low efficiency of energy utilization for collecting packets.In this work,we propose the maximum data generation rate routing protocol based on data flow controlling technology.For a sensor,it does not share its waking schedule to its neighbors and cache any waking schedules of other sensors.Hence,the energy consumption for time synchronization,location information and waking schedule shared will be reduced significantly.The saving energy can be used for improving data collection rate.Simulation shows our scheme is efficient to improve packets generation rate in rechargeable wireless sensor networks.展开更多
Arbuscular mycorrhizal fungi(AMF)form a near-ubiquitous mutualistic association with roots to help plants withstand harsh environments,and play a key role in the establishment of coastal beach plant communities.Yet li...Arbuscular mycorrhizal fungi(AMF)form a near-ubiquitous mutualistic association with roots to help plants withstand harsh environments,and play a key role in the establishment of coastal beach plant communities.Yet little is known about the structure and composition of AMF communities on coastal beaches of eastern China.In this study,we investigated the occurrence,community composition and diversity of AMF associated with common wild plants on a coastal beach of North Jiangsu,China.Almost all of the local wild species were colonized by AMF except for Chenopodium album L.Thirty-seven AMF species were isolated from the rhizosphere belonging to 12 genera in seven families.Glomus was the dominant genus and Funneliformis mosseae the dominant species.The colonization,spore composition and diversity of AMF were strongly related to edaphic factors.Sodium(Na^(+))ions in the soil significantly and negatively affected the colonization rate by AMF and both soil Na^(+)levels and pH had a significant negative effect on AMF spore density and evenness.However,there was a significant positive correlation between species richness and total organic carbon.The results provide insights into soil factors affecting native AMF communities in coastal beach habitats which could benefit vegetation recovery and soil reclamation efforts.展开更多
The purpose of the paper is to provide a way to model the brain functional network based on the complex networks with brain anatomical architecture. We introduce the brain structural and functional researches, and del...The purpose of the paper is to provide a way to model the brain functional network based on the complex networks with brain anatomical architecture. We introduce the brain structural and functional researches, and delineate the brain anatomical and functional networks based on complex networks, then we discuss the brain functional complex network models; at last we put forward the brain functional networks modeling process and the data processing with fMRI （functional magnetic resonance imaging） in detailed.展开更多
Landslides are widespread geomorphological phenomena with complex mechanisms that have caused extensive causalities and property damage worldwide.The scale and frequency of landslides are presently increasing owing to...Landslides are widespread geomorphological phenomena with complex mechanisms that have caused extensive causalities and property damage worldwide.The scale and frequency of landslides are presently increasing owing to the warming effects of climate change,which further increases the associated safety risks.In this study,the relationship between historical landslides and environmental variables in the Hanjiang River Basin was determined and an optimized model was used to constrain the relative contribution of variables and best spatial response curve.The optimal MaxEnt model was used to predict the current distribution of landslides and influence of future rainfall changes on the landslide susceptibility.The results indicate that environmental variables in the study area statistically correlate with landslide events over the past 20 years.The MaxEnt model evaluation was applied to landslide hazards in the Hanjiang River Basin based on current climate change scenarios.The results indicate that 25.9%of the study area is classified as a high-risk area.The main environmental variables that affect the distribution of landslides include altitude,slope,normalized difference vegetation index,annual precipitation,distance from rivers,and distance from roads,with a cumulative contribution rate of approximately 90%.The annual rainfall in the Hanjiang River Basin will continue to increase under future climate warming scenarios.Increased rainfall will further increase the extent of high-and medium-risk areas in the basin,especially when following the RCP8.5 climate prediction,which is expected to increase the high-risk area by 10.7%by 2070.Furthermore,high landslide risk areas in the basin will migrate to high-altitude areas in the future,which poses new challenges for the prevention and control of landslide risks.This study demonstrates the usefulness of the MaxEnt model as a tool for landslide susceptibility prediction in the Hanjiang River Basin caused by global warming and yields robust prediction results.This approach therefore provides an important reference for river basin management and disaster reduction and prevention.The study on landslide risks also supports the hypothesis that global climate change will further enhance the frequency and intensity of landslide activity throughout the course of the 21st Century.展开更多
To reveal the biological characteristics of urban forest soil and the effects of soil enzyme on soil fertility as well as the correlation between physicochemical properties and enzyme activities,44 urban forest soil p...To reveal the biological characteristics of urban forest soil and the effects of soil enzyme on soil fertility as well as the correlation between physicochemical properties and enzyme activities,44 urban forest soil profiles in Nanjing were investigated.Basic soil physicochemical properties and enzyme activities were analyzed in the laboratory.Hydrogen peroxidase,dehydrogenase,alkaline phosphatase,and cellulase were determined by potassium permanganate titration,TTC(C_(19)H_(15)N_(4)·Cl)colorimetry,phenyl phosphate dinatrium colorimetry,and anthrone colorimetry,respectively.The result showed that soil pH,organic carbon(C),and total nitrogen(N)had great effects on hydrogen peroxidase,dehydrogenase,and alkaline phosphatase activities in 0–20 cm thick soil.However,pH only had great effect on hydrogen peroxidase,dehydrogenase,and alkaline phosphatase activities in 20–40 cm thick soil.Hydrogen peroxidase,dehydrogenase,and alkaline phosphatase were important biological indicators for the fertility of urban forest soil.Both in 0–20 cmand 20–40 cmsoil,soil enzyme system(hydrogen peroxidase,dehydrogenase,alkaline phosphatase,and cellulase)had a close relationship with a combination of physicochemical indicators pH,organic C,total N,available K,available P,cation exchange capacity(CEC),and microbial biomass carbon(C_(mic)).The more soil enzyme activities there were,the higher the fertility of urban forest soil.展开更多
To date, research on the adverse effects of continuous cropping has focused on field crops;forest plantations, despite their very significant economic and ecological value, have received less attention. The evolution ...To date, research on the adverse effects of continuous cropping has focused on field crops;forest plantations, despite their very significant economic and ecological value, have received less attention. The evolution of microbial community in the rhizosphere of forest plantations, in particular, has rarely been examined. In this study, changes in the size, composition, and structure of bacterial and fungal communities in the rhizosphere of different generations of poplar (Populus deltoides) plantations were studied using real-time polymerase chain reaction (PCR) and PCR-denaturing gradient gel electrophoresis and compared with the composition of the microbial community in a bare land (control) adjacent to the plantation sites through sequencing analysis and by constructing phylogenetic trees. The numbers of bacteria and fungi increased significantly with successive poplar generations, although the increases in the two groups were not parallel. When compared with the control, the bacterial community increased greatly in the second generation, and the most significant increase occurred in the third generation. In contrast, the most significant increase in the fungal community occurred in the first generation, and the increase in the third generation was insignificant. In terms of community composition, the first generation showed little change in either community;however, the second generation showed remarkable changes in the bacterial community, and the third in the fungal community. The numbers of Gammaproteobacteria,Alphaproteobacteria, and Actinobacteria increased by 10.92%, 7.38%, and 5.46%, respectively, whereas those of Acidobacteria decreased by 18.38%in the second generation. These changes in the number and composition of microbial communities in the rhizosphere could be one of the reasons for the decline in yield and quality associated with long-term monoculture.展开更多
Background:Soil acidification caused by acid rain(AR)can damage plant roots,which in turn negatively impacts plant health.In response to changing AR types,research efforts to elucidate their specific impacts on plants...Background:Soil acidification caused by acid rain(AR)can damage plant roots,which in turn negatively impacts plant health.In response to changing AR types,research efforts to elucidate their specific impacts on plants have become intense.Methods:For this study,we investigated the effects of simulated sulfuric,nitric,and mixed AR on the root systems of Quercus acutissima Carr.and Cunninghamia lanceolata(Lamb.)Hook.under different acidity levels.Results:As the AR S/N ratio and pH decreased,the height growth rate(HGR),basal diameter growth rate(DGR),total root length(TRL)and total root surface area(TRS)of C.lanceolata decreased,whereas the TRL and TRS of Q.acutissima remained the same.When the NO_(3)^(−)concentration in AR was increased,the root activity,superoxide dismutase(SOD)and catalase(CAT)activities of C.lanceolata roots revealed a downward trend;however,the root activity of Q.acutissima and the peroxidase(POD)activity of C.lanceolata roots revealed an upward trend.Further,redundant analysis and structural equation models indicated that AR pH had a greater impact on the HGR of Q.acutissima than that of C.lanceolata,while the impact of the AR S/N ratio on C.lanceolata growth rates was greater than that of Q.acutissima.Conclusions:Our results suggested that the root systems of different tree species had variable responses to AR,and the AR S/N ratio was an important factor affecting plant root growth.This might facilitate new strategies for the culti‑vation and protection of plantations in the future.展开更多
Background:China has been increasingly subject to signifcant acid rain,which has negative impacts on forest ecosystems.Recently,the concentrations of NO_(3)^(−)in acid rain have increased in conjunction with the rapid...Background:China has been increasingly subject to signifcant acid rain,which has negative impacts on forest ecosystems.Recently,the concentrations of NO_(3)^(−)in acid rain have increased in conjunction with the rapid rise of nitrogen deposition,which makes it difcult to precisely quantify the impacts of acid rain on forest ecosystems.Methods:For this study,mesocosm experiments employed a random block design,comprised of ten treatments involving 120 discrete plots(0.6 m×2.0 m).The decomposition of fne roots and dynamics of nutrient loss were evaluated under the stress of three acid rain analogues(e.g.,sulfuric(SO_(4)^(2−)/NO_(3)^(−)5:1),nitric(1:5),and mixed(1:1)).Furthermore,the infuences of soil properties(e.g.,soil pH,soil total carbon,nitrogen,C/N ratio,available phosphorus,available potassium,and enzyme activity)on the decomposition of fne roots were analyzed.Results:The soil pH and decomposition rate of fne root litter decreased when exposed to simulated acid rain with lower pH levels and higher NO_(3)^(−)concentrations.The activities of soil enzymes were signifcantly reduced when subjected to acid rain with higher acidity.The activities of soil urease were more sensitive to the efects of the SO_(4)^(2−)/NO_(3)^(−)(S/N)ratio of acid rain than other soil enzyme activities over four decomposition time periods.Furthermore,the acid rain pH signifcantly infuenced the total carbon(TC)of fne roots during decomposition.However,the S/N ratio of acid rain had signifcant impacts on the total nitrogen(TN).In addition,the pH and S/N ratio of the acid rain had greater impacts on the metal elements(K,Ca,and Al)of fne roots than did TC,TN,and total phosphorus.Structural equation modeling results revealed that the acid rain pH had a stronger indirect impact(0.757)on the decomposition rate of fne roots(via altered soil pH and enzyme activities)than direct efects.However,the indirect efects of the acid rain S/N ratio(0.265)on the fne root decomposition rate through changes in soil urease activities and the content of litter elements were lower than the pH of acid rain.Conclusions:Our results suggested that the acid rain S/N ratio exacerbates the inhibitory efects of acid rain pH on the decomposition of fne root litter.展开更多
基金This work was supported by The National Natural Science Fund of China(Grant No.31670554)The Natural Science Foundation of Jiangsu Province of China(Grant No.BK20161527)+1 种基金We also received three Projects Funded by The Project funded by China Postdoctoral Science Foundation(Grant Nos.2018T110505,2017M611828)The Priority Academic Program Development(PAPD)of Jiangsu Higher Education Institutions.The authors wish to express their appreciation to the reviewers for their helpful suggestions which greatly improved the presentation of this paper.
文摘For rechargeable wireless sensor networks,limited energy storage capacity,dynamic energy supply,low and dynamic duty cycles cause that it is unpractical to maintain a fixed routing path for packets delivery permanently from a source to destination in a distributed scenario.Therefore,before data delivery,a sensor has to update its waking schedule continuously and share them to its neighbors,which lead to high energy expenditure for reestablishing path links frequently and low efficiency of energy utilization for collecting packets.In this work,we propose the maximum data generation rate routing protocol based on data flow controlling technology.For a sensor,it does not share its waking schedule to its neighbors and cache any waking schedules of other sensors.Hence,the energy consumption for time synchronization,location information and waking schedule shared will be reduced significantly.The saving energy can be used for improving data collection rate.Simulation shows our scheme is efficient to improve packets generation rate in rechargeable wireless sensor networks.
基金funded by the Agricultural Science and Technology Independent Innovation Fund of Jiangsu Province of China[Grant No.CX(17)004]the National Special Fund for Forestry Scientific Research in the Public Interest(Grant No.201504406)+2 种基金Major Fund for Natural Science of Jiangsu Higher Education Institutions(Grant No.15KJA220004)Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)the Doctorate Fellowship Foundation of Nanjing Forestry University(2169125)。
文摘Arbuscular mycorrhizal fungi(AMF)form a near-ubiquitous mutualistic association with roots to help plants withstand harsh environments,and play a key role in the establishment of coastal beach plant communities.Yet little is known about the structure and composition of AMF communities on coastal beaches of eastern China.In this study,we investigated the occurrence,community composition and diversity of AMF associated with common wild plants on a coastal beach of North Jiangsu,China.Almost all of the local wild species were colonized by AMF except for Chenopodium album L.Thirty-seven AMF species were isolated from the rhizosphere belonging to 12 genera in seven families.Glomus was the dominant genus and Funneliformis mosseae the dominant species.The colonization,spore composition and diversity of AMF were strongly related to edaphic factors.Sodium(Na^(+))ions in the soil significantly and negatively affected the colonization rate by AMF and both soil Na^(+)levels and pH had a significant negative effect on AMF spore density and evenness.However,there was a significant positive correlation between species richness and total organic carbon.The results provide insights into soil factors affecting native AMF communities in coastal beach habitats which could benefit vegetation recovery and soil reclamation efforts.
基金The authors thank the College of Information and Engineering Taishan Medical University colleagues for assistance with data collection and the manuscript comments. Special thanks to Polly and Xiaochen Xu for suggestions on writing in the English language. The authors are grateful to the anonymous referees for their valuable comments and suggestions. This research was supported by the Natural Science Foundation of Shandong （No. ZR2013FL031）, State Accident Prevention Key Technology of Work Safety Program （No. 2013-084）, Work Safety Science Technology Development Program of Shandong （No. LAJK2013-137）, High-level Training Project of Taishan Medical University （No. 2013GCC09）.
文摘The purpose of the paper is to provide a way to model the brain functional network based on the complex networks with brain anatomical architecture. We introduce the brain structural and functional researches, and delineate the brain anatomical and functional networks based on complex networks, then we discuss the brain functional complex network models; at last we put forward the brain functional networks modeling process and the data processing with fMRI （functional magnetic resonance imaging） in detailed.
基金funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)National Foundation of Forestry Science and Technology Popularization(No.[2015]17)Major Fund for Natural Science of Jiangsu Higher Education Institutions(No.15KJA220004).
文摘Landslides are widespread geomorphological phenomena with complex mechanisms that have caused extensive causalities and property damage worldwide.The scale and frequency of landslides are presently increasing owing to the warming effects of climate change,which further increases the associated safety risks.In this study,the relationship between historical landslides and environmental variables in the Hanjiang River Basin was determined and an optimized model was used to constrain the relative contribution of variables and best spatial response curve.The optimal MaxEnt model was used to predict the current distribution of landslides and influence of future rainfall changes on the landslide susceptibility.The results indicate that environmental variables in the study area statistically correlate with landslide events over the past 20 years.The MaxEnt model evaluation was applied to landslide hazards in the Hanjiang River Basin based on current climate change scenarios.The results indicate that 25.9%of the study area is classified as a high-risk area.The main environmental variables that affect the distribution of landslides include altitude,slope,normalized difference vegetation index,annual precipitation,distance from rivers,and distance from roads,with a cumulative contribution rate of approximately 90%.The annual rainfall in the Hanjiang River Basin will continue to increase under future climate warming scenarios.Increased rainfall will further increase the extent of high-and medium-risk areas in the basin,especially when following the RCP8.5 climate prediction,which is expected to increase the high-risk area by 10.7%by 2070.Furthermore,high landslide risk areas in the basin will migrate to high-altitude areas in the future,which poses new challenges for the prevention and control of landslide risks.This study demonstrates the usefulness of the MaxEnt model as a tool for landslide susceptibility prediction in the Hanjiang River Basin caused by global warming and yields robust prediction results.This approach therefore provides an important reference for river basin management and disaster reduction and prevention.The study on landslide risks also supports the hypothesis that global climate change will further enhance the frequency and intensity of landslide activity throughout the course of the 21st Century.
基金The research was funded by Introduce Abroad Advance Forestry Technology Plan(948 plan)of State Forestry Administration of China(Grant No.2005-4-17)Social Development Foundation of Jiangsu Province of China(Grant No.BS2007064)+1 种基金National“11th Five”Science and Technology support plan of Forestry of China(Grant No.2006BAD03A16)Natural Science Foundation of Jiangsu Province of China(Grant No.BK2001208).
文摘To reveal the biological characteristics of urban forest soil and the effects of soil enzyme on soil fertility as well as the correlation between physicochemical properties and enzyme activities,44 urban forest soil profiles in Nanjing were investigated.Basic soil physicochemical properties and enzyme activities were analyzed in the laboratory.Hydrogen peroxidase,dehydrogenase,alkaline phosphatase,and cellulase were determined by potassium permanganate titration,TTC(C_(19)H_(15)N_(4)·Cl)colorimetry,phenyl phosphate dinatrium colorimetry,and anthrone colorimetry,respectively.The result showed that soil pH,organic carbon(C),and total nitrogen(N)had great effects on hydrogen peroxidase,dehydrogenase,and alkaline phosphatase activities in 0–20 cm thick soil.However,pH only had great effect on hydrogen peroxidase,dehydrogenase,and alkaline phosphatase activities in 20–40 cm thick soil.Hydrogen peroxidase,dehydrogenase,and alkaline phosphatase were important biological indicators for the fertility of urban forest soil.Both in 0–20 cmand 20–40 cmsoil,soil enzyme system(hydrogen peroxidase,dehydrogenase,alkaline phosphatase,and cellulase)had a close relationship with a combination of physicochemical indicators pH,organic C,total N,available K,available P,cation exchange capacity(CEC),and microbial biomass carbon(C_(mic)).The more soil enzyme activities there were,the higher the fertility of urban forest soil.
基金This work was supported by the Special Fund for Forest Scientific Research in the Public Welfare of China(No.201104068).
文摘To date, research on the adverse effects of continuous cropping has focused on field crops;forest plantations, despite their very significant economic and ecological value, have received less attention. The evolution of microbial community in the rhizosphere of forest plantations, in particular, has rarely been examined. In this study, changes in the size, composition, and structure of bacterial and fungal communities in the rhizosphere of different generations of poplar (Populus deltoides) plantations were studied using real-time polymerase chain reaction (PCR) and PCR-denaturing gradient gel electrophoresis and compared with the composition of the microbial community in a bare land (control) adjacent to the plantation sites through sequencing analysis and by constructing phylogenetic trees. The numbers of bacteria and fungi increased significantly with successive poplar generations, although the increases in the two groups were not parallel. When compared with the control, the bacterial community increased greatly in the second generation, and the most significant increase occurred in the third generation. In contrast, the most significant increase in the fungal community occurred in the first generation, and the increase in the third generation was insignificant. In terms of community composition, the first generation showed little change in either community;however, the second generation showed remarkable changes in the bacterial community, and the third in the fungal community. The numbers of Gammaproteobacteria,Alphaproteobacteria, and Actinobacteria increased by 10.92%, 7.38%, and 5.46%, respectively, whereas those of Acidobacteria decreased by 18.38%in the second generation. These changes in the number and composition of microbial communities in the rhizosphere could be one of the reasons for the decline in yield and quality associated with long-term monoculture.
基金funded by the Jiangsu Province Science Foundation for Youths(BK20200785)China Postdoctoral Science Foundation(2018M642260)+2 种基金the National Special Fund for Forestry Scientific Research in the Public Interest(Grant No.201504406)Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)Jiangsu Agriculture Science and Technology Innovation Fund(Grant No.CX(17)1004)。
文摘Background:Soil acidification caused by acid rain(AR)can damage plant roots,which in turn negatively impacts plant health.In response to changing AR types,research efforts to elucidate their specific impacts on plants have become intense.Methods:For this study,we investigated the effects of simulated sulfuric,nitric,and mixed AR on the root systems of Quercus acutissima Carr.and Cunninghamia lanceolata(Lamb.)Hook.under different acidity levels.Results:As the AR S/N ratio and pH decreased,the height growth rate(HGR),basal diameter growth rate(DGR),total root length(TRL)and total root surface area(TRS)of C.lanceolata decreased,whereas the TRL and TRS of Q.acutissima remained the same.When the NO_(3)^(−)concentration in AR was increased,the root activity,superoxide dismutase(SOD)and catalase(CAT)activities of C.lanceolata roots revealed a downward trend;however,the root activity of Q.acutissima and the peroxidase(POD)activity of C.lanceolata roots revealed an upward trend.Further,redundant analysis and structural equation models indicated that AR pH had a greater impact on the HGR of Q.acutissima than that of C.lanceolata,while the impact of the AR S/N ratio on C.lanceolata growth rates was greater than that of Q.acutissima.Conclusions:Our results suggested that the root systems of different tree species had variable responses to AR,and the AR S/N ratio was an important factor affecting plant root growth.This might facilitate new strategies for the culti‑vation and protection of plantations in the future.
基金funded by the Jiangsu Province Science Foundation for Youths(BK20200785)the China Postdoctoral Science Foundation(2018M642260)+1 种基金the Jiangsu Agriculture Science and Technology Innova‑tion Fund(CX(17)1004)the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD).
文摘Background:China has been increasingly subject to signifcant acid rain,which has negative impacts on forest ecosystems.Recently,the concentrations of NO_(3)^(−)in acid rain have increased in conjunction with the rapid rise of nitrogen deposition,which makes it difcult to precisely quantify the impacts of acid rain on forest ecosystems.Methods:For this study,mesocosm experiments employed a random block design,comprised of ten treatments involving 120 discrete plots(0.6 m×2.0 m).The decomposition of fne roots and dynamics of nutrient loss were evaluated under the stress of three acid rain analogues(e.g.,sulfuric(SO_(4)^(2−)/NO_(3)^(−)5:1),nitric(1:5),and mixed(1:1)).Furthermore,the infuences of soil properties(e.g.,soil pH,soil total carbon,nitrogen,C/N ratio,available phosphorus,available potassium,and enzyme activity)on the decomposition of fne roots were analyzed.Results:The soil pH and decomposition rate of fne root litter decreased when exposed to simulated acid rain with lower pH levels and higher NO_(3)^(−)concentrations.The activities of soil enzymes were signifcantly reduced when subjected to acid rain with higher acidity.The activities of soil urease were more sensitive to the efects of the SO_(4)^(2−)/NO_(3)^(−)(S/N)ratio of acid rain than other soil enzyme activities over four decomposition time periods.Furthermore,the acid rain pH signifcantly infuenced the total carbon(TC)of fne roots during decomposition.However,the S/N ratio of acid rain had signifcant impacts on the total nitrogen(TN).In addition,the pH and S/N ratio of the acid rain had greater impacts on the metal elements(K,Ca,and Al)of fne roots than did TC,TN,and total phosphorus.Structural equation modeling results revealed that the acid rain pH had a stronger indirect impact(0.757)on the decomposition rate of fne roots(via altered soil pH and enzyme activities)than direct efects.However,the indirect efects of the acid rain S/N ratio(0.265)on the fne root decomposition rate through changes in soil urease activities and the content of litter elements were lower than the pH of acid rain.Conclusions:Our results suggested that the acid rain S/N ratio exacerbates the inhibitory efects of acid rain pH on the decomposition of fne root litter.
