The objective of reliability-based design optimization(RBDO)is to minimize the optimization objective while satisfying the corresponding reliability requirements.However,the nested loop characteristic reduces the effi...The objective of reliability-based design optimization(RBDO)is to minimize the optimization objective while satisfying the corresponding reliability requirements.However,the nested loop characteristic reduces the efficiency of RBDO algorithm,which hinders their application to high-dimensional engineering problems.To address these issues,this paper proposes an efficient decoupled RBDO method combining high dimensional model representation(HDMR)and the weight-point estimation method(WPEM).First,we decouple the RBDO model using HDMR and WPEM.Second,Lagrange interpolation is used to approximate a univariate function.Finally,based on the results of the first two steps,the original nested loop reliability optimization model is completely transformed into a deterministic design optimization model that can be solved by a series of mature constrained optimization methods without any additional calculations.Two numerical examples of a planar 10-bar structure and an aviation hydraulic piping system with 28 design variables are analyzed to illustrate the performance and practicability of the proposed method.展开更多
Water pollution of the Yangtze River in China became one of challenges that the government is facing today.Increasing numbers of petrochemical plants were built along the river in past decades,and numbers of organic c...Water pollution of the Yangtze River in China became one of challenges that the government is facing today.Increasing numbers of petrochemical plants were built along the river in past decades,and numbers of organic chemicals were discharged into the river.Our goal was to establish in vitro system on rat sertoli cells,spermatogenic cells and leydig cells to investigate the reproductive toxicity potential induced by organic extracts from petrochemical effluents.Our results showed that the organic extract depressed the viability(p<0.01) and destroyed the plasma membrane integrity of sertoli cells and spermatogenic cells to a certain degree.Accordingly,proportion of early apoptotic sertoli cells and late apoptotic spermatogenic cells increased significantly.Although significant morphological changes were not detected for leydig cells,the extract was observed to inhibit their testosterone production(p<0.01).Sertoli cells and spermatogenic cells appeared to be more sensitive and maybe the main targets of the key toxins.These results suggested that the in vitro system on rat testicular cells may be useful to predicate reproductive toxicity potential of organic extracts from petrochemical effluents.More attention should be paid to the petrochemical effluents,because long-term accumulation of these organic compounds in organisms may cause spermatogenesis malfunction and testosterone reduction.展开更多
Identifying a superior soybean variety with high defoliator resistance is important to avoid yield loss. Cotton bollworm(Helicoverpa armigera Hübner) is one of the major defoliators of soybean(Glycine max [L.] Me...Identifying a superior soybean variety with high defoliator resistance is important to avoid yield loss. Cotton bollworm(Helicoverpa armigera Hübner) is one of the major defoliators of soybean(Glycine max [L.] Merr.) worldwide. In this study, we evaluated the effect of H. armigera larvae on ED059, a wild soybean(Glycine soja Sieb. et Zucc.), and three cultivated soybean varieties: Tianlong 2, PI 535807, and PI 533604, in choice and no-choice assays. The percentage of ED059 leaflets consumed by H. armigera was lower than that of the three cultivated soybeans. Larvae that fed on ED059 exhibited low weight gain and high mortality rate.Waldbauer nutritional indices suggested that ED059 reduced the growth, consumption, and frass production of H. armigera larvae. Larvae that fed on ED059 showed lower efficiency of conversion of ingested and of digested food than those that fed on Tianlong 2 and PI 533604.However, they showed statistically similar consumption index and approximate digestibility compared with those fed on the three cultivated soybeans. Quantitative real-time PCR analysis revealed that 24 h after insect attack, ED059 had higher transcript levels of Kunitz trypsin inhibitor 3, Cysteine proteinase inhibitor 2, and Nerolidol synthase 1 but a lower transcript level of Pathogenesis-related protein 1 than Tianlong 2. The gene expression results were consistent with the presence of higher levels of jasmonic acid(JA) and transcript levels of the JA biosynthesis enzyme allene oxide cyclase 3 in ED059 than in Tianlong 2. Our findings indicate that ED059 is a superior soybean line with strong insect resistance that may be mediated via the JA pathway.展开更多
Coexistence mechanisms for species with similar ecological traits and overlapping geographic distributions are basic questions in ecology and evolutionary biology. Specific habitat requirements often limit distributio...Coexistence mechanisms for species with similar ecological traits and overlapping geographic distributions are basic questions in ecology and evolutionary biology. Specific habitat requirements often limit distribution range as well as facilitate partitioning resource utilization in ecological similar species. Understanding niche segregation and differences in microhabitat utilization can contribute to identifying coexistence mechanisms between parapatric species. Feirana quadranus and F. taihangnica are two closely related frog species with parapatric geographic ranges and an elongated contact zone within the Qinling Mountains, which is an important watershed for East Asia. Here, we analysed the difference in microhabitat utilization between the two frog species and explored the key ecological factors that induced their microhabitat differentiation based on quadrats sampled in the contact zone. Our comparison of twenty environmental variables showed that both species used microhabitats with alkalescent warm water and gentle slope conditions. The principal component analysis indicated that climate-related variables, vegetation conditions, and river width were the important factors for microhabitat utilization of these species. These findings contribute to our understanding on the coexistence mechanisms of these two related and parapatric Asian mountain frog species. This study can also be helpful for identifying target habitats to conduct conservation actions and management strategies effectively in the face of environmental changes.展开更多
Background:In biological systems,biological diversity often displays a rapid turn-over across elevations.This defining feature has made mountains classic systems for studying the spatial variation in diversity.Because...Background:In biological systems,biological diversity often displays a rapid turn-over across elevations.This defining feature has made mountains classic systems for studying the spatial variation in diversity.Because patterns of elevational diversity can vary among lineages and mountain systems it remains difficult to extrapolate findings from one montane region to another,or among lineages.In this study,we assessed patterns and drivers of avian diversity along an elevational gradient on the eastern slope of Mt.Gongga,the highest peak in the Hengduan Mountain Range in central China,and a mountain where comprehensive studies of avian diversity are still lacking.Methods:We surveyed bird species in eight 400-m elevational bands from 1200 to 4400 m a.s.l.between 2012 and 2017.To test the relationship between bird species richness and environmental factors,we examined the relative importance of seven ecological variables on breeding season distribution patterns:land area(LA),mean daily temperature(MDT),seasonal temperature range(STR),the mid-domain effect(MDE),seasonal precipitation(SP),invertebrate biomass(IB) and enhanced vegetation index(EVI).Climate data were obtained from five local meteorological stations and three temperature/relative humidity smart sensors in 2016.Results:A total of 219 bird species were recorded in the field,of which 204 were recorded during the breeding season(April–August).Species richness curves(calculated separately for total species,large-ranged species,and smallranged species) were all hump-shaped.Large-ranged species contributed more to the total species richness pattern than small-ranged species.EVI and IB were positively correlated with total species richness and small-ranged species richness.LA and MDT were positively correlated with small-ranged species richness,while STR and SP were negatively correlated with small-ranged species richness.MDE was positively correlated with large-ranged species richness.When we considered the combination of candidate factors using multiple regression models and model-averaging,total species richness and large-ranged species richness were correlated with STR(negative) and MDE(positive),while small-ranged species richness was correlated with STR(negative) and IB(positive).Conclusions:Although no single key factor or suite of factors could explain patterns of diversity,we found that MDE,IB and STR play important but varying roles in shaping the elevational richness patterns of different bird species categories.Model-averaging indicates that small-ranged species appear to be mostly influenced by IB,as opposed to large-ranged species,which exhibit patterns more consistent with the MDE model.Our data also indicate that the species richness varied between seasons,offering a promising direction for future work.展开更多
Plants have evolved sophisticated defense mechanisms against herbivores to help them adapt to the environment. Understanding the defense mechanisms in plants can help us control insects in a more effective manner. In ...Plants have evolved sophisticated defense mechanisms against herbivores to help them adapt to the environment. Understanding the defense mechanisms in plants can help us control insects in a more effective manner. In this study, we found that compared with Tianlong 2(a cultivated soybean with insect susceptibility), ED059(a wild soybean line with insect resistance)contains sharper pubescence tips, as well as lower transcript levels of wound-induced protein kinase(WIPK) and salicylic acid-induced protein kinase(SIPK), which are important mitogen-activated protein kinases involved in early defense response to herbivores. The observed lower transcript levels of WIPK and SIPK induced higher levels of jasmonic acid(JA), JA biosynthesis enzymes(AOC3) and some secondary metabolites in ED059. Functional analysis of the KTI1 gene via Agrobacterium-mediated transformation in Arabidopsis thaliana indicated that it plays an important role in herbivore defense in ED059. We further investigated the molecular response of third-instar Helicoverpa armigera(Hübner) larvae to Tianlong 2 and ED059. We found apoptotic cells only in the midguts of larvae that fed on ED059. Compared with larvae reared on the susceptible cultivar Tianlong 2, transcript levels of catalase(CAT) and glutathione S-transferase(GST) were up-regulated, whereas those of CAR, CHSB, and TRY were down-regulated in larvae that fed on the highly resistant variety ED059. We propose that these differences underlie the different herbivore defense responses of ED059 and Tianlong 2.展开更多
Brookite TiO_2,the latest TiO_2 photocatalyst,promises to be an interesting candidate for photocatalytic applications because of its unique physical and chemical properties. In this study,pure-phase brookite TiO_2 wit...Brookite TiO_2,the latest TiO_2 photocatalyst,promises to be an interesting candidate for photocatalytic applications because of its unique physical and chemical properties. In this study,pure-phase brookite TiO_2 with a quasi-spherical nanostructure was successfully synthesized via a solvothermal method using tetrabutyl titanate(Ti(OC_4H_9)_4,TBOT) as the Ti source in the presence of oxalic acid. NaOH was used to regulate the pH of solution. The structure and morphology of the samples were then analyzed using multiple methods,such as X-ray diff raction(XRD),Raman spectroscopy,scanning electron microscopy(SEM),transmission electron microscopy(TEM),Brunauer–Emmett–Teller(BET) measurements and ultraviolet–visible diff use spectroscopy(UV–Vis). Photocatalytic activities of the as-synthesized brookite TiO_2 were evaluated by degrading aqueous methylene blue solution under UV light irradiation. The effect of thermal treatment temperature on photocatalytic activity of the samples was also investigated. The produced brookite TiO_2 nanopowders calcined at 500 °C for 2 h showed the highest photocatalytic activity,and the corresponding degradation rate of methylene blue(10 mg/L) reached 96.7% after 90 min of illumination. In addition,the formation mechanism of pure-phase brookite TiO_2 was investigated. It was found that the formation of pure-phase brookite TiO_2 in this study was ascribed to the combined action of oxalic acid and sodium hydroxide.展开更多
TiO_2 nanotubes(TNTs) have drawn tremendous attention owing to their unique architectural and physical properties. Anodizing of titanium foil has proven to be the most efficient method to fabricate well-aligned TNTs,w...TiO_2 nanotubes(TNTs) have drawn tremendous attention owing to their unique architectural and physical properties. Anodizing of titanium foil has proven to be the most efficient method to fabricate well-aligned TNTs,which, however, usually produces amorphous TNTs and needs further thermal annealing. Recently, a water-assisted crystallization strategy has been proposed and investigated by both science and engineering communities. This method is very efficient and energy saving, and it circumvents the drawbacks of thermal sintering approach. In this paper, we review the recent research progress in this kind of lowtemperature crystallization approach. Here, various synthetic methods are summarized, and the mechanisms of the amorphous–crystalline transformation are analyzed. The fundamental properties and applications of the low-temperature products are also discussed. Furthermore, it is proved that the water-assisted crystallization approach is not only applicable to TNTs but also to crystallizing other metal oxides.展开更多
In multiple sclerosis, gray matter atrophy is extensive, and cognitive deficits and mood disorders are frequently encountered. It has been conjectured that focal atrophy is associated with emotional decline. However, ...In multiple sclerosis, gray matter atrophy is extensive, and cognitive deficits and mood disorders are frequently encountered. It has been conjectured that focal atrophy is associated with emotional decline. However, conventional MRI has revealed that the pathological characteristics cannot fully account for the mood disorders. Moreover, there is no correlation between cognitive disorders and MRI results in clinically isolated syndromes or in cases of definite multiple sclerosis. In this casecontrol study, voxel-based morphometric analysis was performed on 11 subjects with relapsing-remitting multiple sclerosis, and the results show that these patients exhibit gray matter atrophy. Moreover, the gray matter atrophy in the superior and middle gyri of the right frontal lobe in patients with multiple sclerosis was correlated with scores from the Hamilton Anxiety Rating Scale. The scores obtained with the Repeatable Battery for the Assessment of Neuropsychological Status were associated with gray matter atrophy in the middle gyrus of the left frontal lobe, the superior and middle gyrus of the right frontal lobe, the middle gyrus of the left cingulate, the superior and middle gyri of the left frontal lobe, and the triangular area of the left frontal lobe. However, there was no statistical significance. These findings suggest that the cingulate and frontal cortices of the dominant hemisphere are the most severely atrophic regions of the brain, and this atrophy is correlated with cognitive decline and emotional abnormalities.展开更多
The importance analysis method represents a powerful tool for quantifying the impact of input uncertainty on the output uncertainty.When an input variable is described by a specific interval rather than a certain prob...The importance analysis method represents a powerful tool for quantifying the impact of input uncertainty on the output uncertainty.When an input variable is described by a specific interval rather than a certain probability distribution,the interval importance measure of input interval variable can be calculated by the traditional non-probabilistic importance analysis methods.Generally,the non-probabilistic importance analysis methods involve the Monte Carlo simulation(MCS)and the optimization-based methods,which both have high computational cost.In order to overcome this problem,this study proposes an interval important analytical method avoids the time-consuming optimization process.First,the original performance function is decomposed into a combination of a series of one-dimensional subsystems.Next,the interval of each variable is divided into several subintervals,and the response value of each one-dimensional subsystem at a specific input point is calculated.Then,the obtained responses are taken as specific values of the new input variable,and the interval importance is calculated by the approximated performance function.Compared with the traditional non-probabilistic importance analysis method,the proposed method significantly reduces the computational cost caused by the MCS and optimization process.In the proposed method,the number of function evaluations is equal to one plus the sum of the subintervals of all of the variables.The efficiency and accuracy of the proposed method are verified by five examples.The results show that the proposed method is not only efficient but also accurate.展开更多
Underwater sensor networks have important application value in the fields of water environment data collection,marine environment monitoring and so on.It has some characteristics such as low available bandwidth,large ...Underwater sensor networks have important application value in the fields of water environment data collection,marine environment monitoring and so on.It has some characteristics such as low available bandwidth,large propagation delays and limited energy,which bring new challenges to the current researches.The research on coverage control of underwater sensor networks is the basis of other related researches.A good sensor node coverage control method can effectively improve the quality of water environment monitoring.Aiming at the problem of high dynamics and uncertainty of monitoring targets,the random events level are divided into serious events and general events.The sensors are set to sense different levels of events and make different responses.Then,an event-driven optimization algorithm for determining sensor target location based on self-organization map is proposed.Aiming at the problem of limited energy of underwater sensor nodes,considering the moving distance,coverage redundancy and residual energy of sensor nodes,an underwater sensor movement control algorithm based on residual energy probability is proposed.The simulation results show that compared with the simple movement algorithm,the proposed algorithm can effectively improve the coverage and life cycle of the sensor networks,and realize real-time monitoring of the water environment.展开更多
Wireless sensor networks(WSN)can be used in many fields.In wireless sensor networks,sensor nodes transmit data in multi hop mode.The large number of hops required by data transmission will lead to unbalanced energy co...Wireless sensor networks(WSN)can be used in many fields.In wireless sensor networks,sensor nodes transmit data in multi hop mode.The large number of hops required by data transmission will lead to unbalanced energy consumption and large data transmission delay of the whole network,which greatly affects the invulnerability of the network.Therefore,an optimal deployment of heterogeneous nodes(ODHN)algorithm is proposed to enhance the invulnerability of the wireless sensor networks.The algorithm combines the advantages of DEEC(design of distributed energy efficient clustering)clustering algorithm and BAS(beetle antenna search)optimization algorithm to find the globally optimal deployment locations of heterogeneous nodes.Then,establish a shortcut to communicate with sink nodes through heterogeneous nodes.Besides,considering the practical deployment operation,we set the threshold of the mobile location of heterogeneous nodes,which greatly simplifies the deployment difficulty.Simulation results show that compared with traditional routing protocols,the proposed algorithm can make the network load more evenly,and effectively improve energy-utilization and the fault tolerance of the whole network,which can greatly improve the invulnerability of the wireless sensor networks.展开更多
Wireless Sensor Network(WSN)is an important part of the Internet of Things(IoT),which are used for information exchange and communication between smart objects.In practical applications,WSN lifecycle can be influenced...Wireless Sensor Network(WSN)is an important part of the Internet of Things(IoT),which are used for information exchange and communication between smart objects.In practical applications,WSN lifecycle can be influenced by the unbalanced distribution of node centrality and excessive energy consumption,etc.In order to overcome these problems,a heterogeneous wireless sensor network model with small world characteristics is constructed to balance the centrality and enhance the invulnerability of the network.Also,a new WSN centrality measurement method and a new invulnerability measurement model are proposed based on the WSN data transmission characteristics.Simulation results show that the life cycle and data transmission volume of the network can be improved with a lower network construction cost,and the invulnerability of the network is effectively enhanced.展开更多
Water quality sensor networks are promising tools for the exploration of oceans.Some key areas need to be monitored effectively.Water quality sensors are deployed randomly or uniformly,however,and understanding how to...Water quality sensor networks are promising tools for the exploration of oceans.Some key areas need to be monitored effectively.Water quality sensors are deployed randomly or uniformly,however,and understanding how to deploy sensor nodes reasonably and realize effective monitoring of key areas on the basis of monitoring the whole area is an urgent problem to be solved.Additionally,energy is limited in water quality sensor networks.When moving sensor nodes,we should extend the life cycle of the sensor networks as much as possible.In this study,sensor nodes in non-key monitored areas are moved to key areas.First,we used the concentric circle method to determine the mobile sensor nodes and the target locations.Then,we determined the relationship between the mobile sensor nodes and the target locations according to the energy matrix.Finally,we calculated the shortest moving path according to the Floyd algorithm,which realizes the redeployment of the key monitored area.The simulation results showed that,compared with the method of direct movement,the proposed method can effectively reduce the energy consumption and save the network adjustment time based on the effective coverage of key areas.展开更多
Water quality sensor networks are widely used in water resource monitoring.However,due to the fact that the energy of these networks cannot be supplemented in time,it is necessary to study effective routing protocols ...Water quality sensor networks are widely used in water resource monitoring.However,due to the fact that the energy of these networks cannot be supplemented in time,it is necessary to study effective routing protocols to extend their lifecycle.To address the problem of limited resources,a routing optimization algorithm based on a small-world network model is proposed.In this paper,a small-world network model is introduced for water quality sensor networks,in which the short average path and large clustering coefficient of the model are used to construct a super link.A short average path can reduce the network’s energy consumption,and a large coefficient can improve its fault-tolerance ability.However,the energy consumption of the relay nodes near the heterogeneous node is too great,and as such the energy threshold and non-uniform clustering are constructed to improve the lifecycle of the network.Simulation results show that,compared with the low-energy adaptive clustering hierarchy routing algorithm and the best sink location clustering heterogeneous network routing algorithm,the proposed improved routing model can effectively enhance the energy-utilization.The lifecycle of the network can be extended and the data transmission amount can be greatly increased.展开更多
Background:Spatial variation of land cover can result in the changes of community similarities and biotic homog-enization,whereby the increasing similarity would reduce the adaptive capacity of biotic assemblages to f...Background:Spatial variation of land cover can result in the changes of community similarities and biotic homog-enization,whereby the increasing similarity would reduce the adaptive capacity of biotic assemblages to further disturbance,and degenerate ecosystem services they offer.However,it remains scarce to integrate multidimensional diversity for unveiling how variations in land cover may influence the patterns and processes of biotic homogeniza-tion in the Anthropocene.In this study,we examined how spatial variation of land cover could alter taxonomic,phy-logenetic and functional homogenization of bird communities simultaneously in a compound ecosystem of Zoige Marsh on the eastern Qinghai-Tibetan Plateau.Acting as the largest alpine marsh and peatland in the world,Zoige Marsh has undergone great changes in the land cover pattern due to climate change and anthropogenic activities.Methods:We conducted transect surveys for bird communities over six years(2014‒2019)during breeding sea-sons in four main land cover types(meadow,woodland,village and marsh),representing the spatial variation of land covers in the study area.We compared multidimensional diversity(taxonomic,phylogenetic and functional diver-sity)among land covers to assess the effects of spatial variation in land cover type on bird communities,particularly whether this variation has homogenized biotic communities.Results:Bird communities during breeding seasons were different and complementary in the four land covers.Taxonomic,phylogenetic and functional similarities were significantly lower in meadow than in the other three types,i.e.woodland,village and marsh.However,when we controlled for the effects of taxonomic similarities,the pattern of phylogenetic similarities almost reversed,with the highest standardized effect size(SES)phylogenetic similarity in meadow;and we found no significant difference in SES functional similarity among land covers.Conclusions:Our results suggest that spatial variation of land cover can play a crucial role in regulating multiple dimensions of bird diversity in Zoige Marsh.The findings indicate that taxonomic,phylogenetic and functional homogenization of bird communities may differently response to the variation of land covers.It thus highlights not only the relative roles of different land covers in maintaining biodiversity and community structures of birds,but also the urgency of retarding ecosystem degradations on the eastern Qinghai-Tibetan Plateau.展开更多
基金supported by the Innovation Fund Project of the Gansu Education Department(Grant No.2021B-099).
文摘The objective of reliability-based design optimization(RBDO)is to minimize the optimization objective while satisfying the corresponding reliability requirements.However,the nested loop characteristic reduces the efficiency of RBDO algorithm,which hinders their application to high-dimensional engineering problems.To address these issues,this paper proposes an efficient decoupled RBDO method combining high dimensional model representation(HDMR)and the weight-point estimation method(WPEM).First,we decouple the RBDO model using HDMR and WPEM.Second,Lagrange interpolation is used to approximate a univariate function.Finally,based on the results of the first two steps,the original nested loop reliability optimization model is completely transformed into a deterministic design optimization model that can be solved by a series of mature constrained optimization methods without any additional calculations.Two numerical examples of a planar 10-bar structure and an aviation hydraulic piping system with 28 design variables are analyzed to illustrate the performance and practicability of the proposed method.
基金supported by the Fundamental Research Funds for the Central Non-profit Research Institution of CAF(CAFYBB2018ZB001)the National Key R&D Program of China(2018YFC1200400)
基金supported by the Major State Basic Research Development Program (No.2008CB418102)the Environmental Monitoring Research Foundation of Jiangsu Province (No.0710)+1 种基金the Innovation Foundation for Youth Scholars of the State Key Laboratory of Pollution Control and Resource Reuse (No.PCRREF07002)the Specialized Research Fund for the Doctoral Program of Higher Education, SRFDP (No.200802841030)
文摘Water pollution of the Yangtze River in China became one of challenges that the government is facing today.Increasing numbers of petrochemical plants were built along the river in past decades,and numbers of organic chemicals were discharged into the river.Our goal was to establish in vitro system on rat sertoli cells,spermatogenic cells and leydig cells to investigate the reproductive toxicity potential induced by organic extracts from petrochemical effluents.Our results showed that the organic extract depressed the viability(p<0.01) and destroyed the plasma membrane integrity of sertoli cells and spermatogenic cells to a certain degree.Accordingly,proportion of early apoptotic sertoli cells and late apoptotic spermatogenic cells increased significantly.Although significant morphological changes were not detected for leydig cells,the extract was observed to inhibit their testosterone production(p<0.01).Sertoli cells and spermatogenic cells appeared to be more sensitive and maybe the main targets of the key toxins.These results suggested that the in vitro system on rat testicular cells may be useful to predicate reproductive toxicity potential of organic extracts from petrochemical effluents.More attention should be paid to the petrochemical effluents,because long-term accumulation of these organic compounds in organisms may cause spermatogenesis malfunction and testosterone reduction.
基金funded by the China Agriculture Research System (CAAS-04-PS08)the National Transgenic Project of China (2014ZX08004-005)the Agricultural Science and Technology Innovation Program of China
文摘Identifying a superior soybean variety with high defoliator resistance is important to avoid yield loss. Cotton bollworm(Helicoverpa armigera Hübner) is one of the major defoliators of soybean(Glycine max [L.] Merr.) worldwide. In this study, we evaluated the effect of H. armigera larvae on ED059, a wild soybean(Glycine soja Sieb. et Zucc.), and three cultivated soybean varieties: Tianlong 2, PI 535807, and PI 533604, in choice and no-choice assays. The percentage of ED059 leaflets consumed by H. armigera was lower than that of the three cultivated soybeans. Larvae that fed on ED059 exhibited low weight gain and high mortality rate.Waldbauer nutritional indices suggested that ED059 reduced the growth, consumption, and frass production of H. armigera larvae. Larvae that fed on ED059 showed lower efficiency of conversion of ingested and of digested food than those that fed on Tianlong 2 and PI 533604.However, they showed statistically similar consumption index and approximate digestibility compared with those fed on the three cultivated soybeans. Quantitative real-time PCR analysis revealed that 24 h after insect attack, ED059 had higher transcript levels of Kunitz trypsin inhibitor 3, Cysteine proteinase inhibitor 2, and Nerolidol synthase 1 but a lower transcript level of Pathogenesis-related protein 1 than Tianlong 2. The gene expression results were consistent with the presence of higher levels of jasmonic acid(JA) and transcript levels of the JA biosynthesis enzyme allene oxide cyclase 3 in ED059 than in Tianlong 2. Our findings indicate that ED059 is a superior soybean line with strong insect resistance that may be mediated via the JA pathway.
基金supported by National Natural Science Foundation of China (31572290, 31770568, and 31770427)Youth Innovation Promotion Association CAS (2015304)+2 种基金National Key Research and Development Plan (2016YFC0503303)China Scholarship Council (No. 201706775008)the project from Qinghai Provincial Communication Department (31118022)
文摘Coexistence mechanisms for species with similar ecological traits and overlapping geographic distributions are basic questions in ecology and evolutionary biology. Specific habitat requirements often limit distribution range as well as facilitate partitioning resource utilization in ecological similar species. Understanding niche segregation and differences in microhabitat utilization can contribute to identifying coexistence mechanisms between parapatric species. Feirana quadranus and F. taihangnica are two closely related frog species with parapatric geographic ranges and an elongated contact zone within the Qinling Mountains, which is an important watershed for East Asia. Here, we analysed the difference in microhabitat utilization between the two frog species and explored the key ecological factors that induced their microhabitat differentiation based on quadrats sampled in the contact zone. Our comparison of twenty environmental variables showed that both species used microhabitats with alkalescent warm water and gentle slope conditions. The principal component analysis indicated that climate-related variables, vegetation conditions, and river width were the important factors for microhabitat utilization of these species. These findings contribute to our understanding on the coexistence mechanisms of these two related and parapatric Asian mountain frog species. This study can also be helpful for identifying target habitats to conduct conservation actions and management strategies effectively in the face of environmental changes.
基金supported by the National Natural Science Foundation of China Granted to Yongjie Wu(No.31501851,31772478)the Chinese Academy of Sciences Visiting Professorship for Senior International Scientists to Per Alstrom(No.2011T2S04)
文摘Background:In biological systems,biological diversity often displays a rapid turn-over across elevations.This defining feature has made mountains classic systems for studying the spatial variation in diversity.Because patterns of elevational diversity can vary among lineages and mountain systems it remains difficult to extrapolate findings from one montane region to another,or among lineages.In this study,we assessed patterns and drivers of avian diversity along an elevational gradient on the eastern slope of Mt.Gongga,the highest peak in the Hengduan Mountain Range in central China,and a mountain where comprehensive studies of avian diversity are still lacking.Methods:We surveyed bird species in eight 400-m elevational bands from 1200 to 4400 m a.s.l.between 2012 and 2017.To test the relationship between bird species richness and environmental factors,we examined the relative importance of seven ecological variables on breeding season distribution patterns:land area(LA),mean daily temperature(MDT),seasonal temperature range(STR),the mid-domain effect(MDE),seasonal precipitation(SP),invertebrate biomass(IB) and enhanced vegetation index(EVI).Climate data were obtained from five local meteorological stations and three temperature/relative humidity smart sensors in 2016.Results:A total of 219 bird species were recorded in the field,of which 204 were recorded during the breeding season(April–August).Species richness curves(calculated separately for total species,large-ranged species,and smallranged species) were all hump-shaped.Large-ranged species contributed more to the total species richness pattern than small-ranged species.EVI and IB were positively correlated with total species richness and small-ranged species richness.LA and MDT were positively correlated with small-ranged species richness,while STR and SP were negatively correlated with small-ranged species richness.MDE was positively correlated with large-ranged species richness.When we considered the combination of candidate factors using multiple regression models and model-averaging,total species richness and large-ranged species richness were correlated with STR(negative) and MDE(positive),while small-ranged species richness was correlated with STR(negative) and IB(positive).Conclusions:Although no single key factor or suite of factors could explain patterns of diversity,we found that MDE,IB and STR play important but varying roles in shaping the elevational richness patterns of different bird species categories.Model-averaging indicates that small-ranged species appear to be mostly influenced by IB,as opposed to large-ranged species,which exhibit patterns more consistent with the MDE model.Our data also indicate that the species richness varied between seasons,offering a promising direction for future work.
基金funded by the China Agriculture Research System(CAAS-04-PS08)the National Transgenic Project of China(2014ZX08004-005)the Agricultural Science and Technology Innovation Program of China
文摘Plants have evolved sophisticated defense mechanisms against herbivores to help them adapt to the environment. Understanding the defense mechanisms in plants can help us control insects in a more effective manner. In this study, we found that compared with Tianlong 2(a cultivated soybean with insect susceptibility), ED059(a wild soybean line with insect resistance)contains sharper pubescence tips, as well as lower transcript levels of wound-induced protein kinase(WIPK) and salicylic acid-induced protein kinase(SIPK), which are important mitogen-activated protein kinases involved in early defense response to herbivores. The observed lower transcript levels of WIPK and SIPK induced higher levels of jasmonic acid(JA), JA biosynthesis enzymes(AOC3) and some secondary metabolites in ED059. Functional analysis of the KTI1 gene via Agrobacterium-mediated transformation in Arabidopsis thaliana indicated that it plays an important role in herbivore defense in ED059. We further investigated the molecular response of third-instar Helicoverpa armigera(Hübner) larvae to Tianlong 2 and ED059. We found apoptotic cells only in the midguts of larvae that fed on ED059. Compared with larvae reared on the susceptible cultivar Tianlong 2, transcript levels of catalase(CAT) and glutathione S-transferase(GST) were up-regulated, whereas those of CAR, CHSB, and TRY were down-regulated in larvae that fed on the highly resistant variety ED059. We propose that these differences underlie the different herbivore defense responses of ED059 and Tianlong 2.
基金supported by the National Key Basic Research and Development Program of China ("973" Program, No. 2012CB720100 and No. 2014CB239300)the National Natural Science Foundation of China (No. 21406164, No. 21466035 and No. 21501196)+2 种基金the Science and Technology Innovation Guide Funds of Civil Aviation Administration of China (MHRD20140209)the Fundamental Research Funds for the Central Universities (No. 3122016L016)University’s Training Programs of Innovation and Entrepreneurship for Undergraduates from Civil Aviation University of China (2017)
文摘Brookite TiO_2,the latest TiO_2 photocatalyst,promises to be an interesting candidate for photocatalytic applications because of its unique physical and chemical properties. In this study,pure-phase brookite TiO_2 with a quasi-spherical nanostructure was successfully synthesized via a solvothermal method using tetrabutyl titanate(Ti(OC_4H_9)_4,TBOT) as the Ti source in the presence of oxalic acid. NaOH was used to regulate the pH of solution. The structure and morphology of the samples were then analyzed using multiple methods,such as X-ray diff raction(XRD),Raman spectroscopy,scanning electron microscopy(SEM),transmission electron microscopy(TEM),Brunauer–Emmett–Teller(BET) measurements and ultraviolet–visible diff use spectroscopy(UV–Vis). Photocatalytic activities of the as-synthesized brookite TiO_2 were evaluated by degrading aqueous methylene blue solution under UV light irradiation. The effect of thermal treatment temperature on photocatalytic activity of the samples was also investigated. The produced brookite TiO_2 nanopowders calcined at 500 °C for 2 h showed the highest photocatalytic activity,and the corresponding degradation rate of methylene blue(10 mg/L) reached 96.7% after 90 min of illumination. In addition,the formation mechanism of pure-phase brookite TiO_2 was investigated. It was found that the formation of pure-phase brookite TiO_2 in this study was ascribed to the combined action of oxalic acid and sodium hydroxide.
基金financially supported by the National R&D Program of China under No.2017YFA0207400National Key Research and Development Plan under No.2016YFA0300801National Natural Science Foundation of China under Nos.51502033,61571079,61131005 and 51572042
文摘TiO_2 nanotubes(TNTs) have drawn tremendous attention owing to their unique architectural and physical properties. Anodizing of titanium foil has proven to be the most efficient method to fabricate well-aligned TNTs,which, however, usually produces amorphous TNTs and needs further thermal annealing. Recently, a water-assisted crystallization strategy has been proposed and investigated by both science and engineering communities. This method is very efficient and energy saving, and it circumvents the drawbacks of thermal sintering approach. In this paper, we review the recent research progress in this kind of lowtemperature crystallization approach. Here, various synthetic methods are summarized, and the mechanisms of the amorphous–crystalline transformation are analyzed. The fundamental properties and applications of the low-temperature products are also discussed. Furthermore, it is proved that the water-assisted crystallization approach is not only applicable to TNTs but also to crystallizing other metal oxides.
文摘In multiple sclerosis, gray matter atrophy is extensive, and cognitive deficits and mood disorders are frequently encountered. It has been conjectured that focal atrophy is associated with emotional decline. However, conventional MRI has revealed that the pathological characteristics cannot fully account for the mood disorders. Moreover, there is no correlation between cognitive disorders and MRI results in clinically isolated syndromes or in cases of definite multiple sclerosis. In this casecontrol study, voxel-based morphometric analysis was performed on 11 subjects with relapsing-remitting multiple sclerosis, and the results show that these patients exhibit gray matter atrophy. Moreover, the gray matter atrophy in the superior and middle gyri of the right frontal lobe in patients with multiple sclerosis was correlated with scores from the Hamilton Anxiety Rating Scale. The scores obtained with the Repeatable Battery for the Assessment of Neuropsychological Status were associated with gray matter atrophy in the middle gyrus of the left frontal lobe, the superior and middle gyrus of the right frontal lobe, the middle gyrus of the left cingulate, the superior and middle gyri of the left frontal lobe, and the triangular area of the left frontal lobe. However, there was no statistical significance. These findings suggest that the cingulate and frontal cortices of the dominant hemisphere are the most severely atrophic regions of the brain, and this atrophy is correlated with cognitive decline and emotional abnormalities.
文摘The importance analysis method represents a powerful tool for quantifying the impact of input uncertainty on the output uncertainty.When an input variable is described by a specific interval rather than a certain probability distribution,the interval importance measure of input interval variable can be calculated by the traditional non-probabilistic importance analysis methods.Generally,the non-probabilistic importance analysis methods involve the Monte Carlo simulation(MCS)and the optimization-based methods,which both have high computational cost.In order to overcome this problem,this study proposes an interval important analytical method avoids the time-consuming optimization process.First,the original performance function is decomposed into a combination of a series of one-dimensional subsystems.Next,the interval of each variable is divided into several subintervals,and the response value of each one-dimensional subsystem at a specific input point is calculated.Then,the obtained responses are taken as specific values of the new input variable,and the interval importance is calculated by the approximated performance function.Compared with the traditional non-probabilistic importance analysis method,the proposed method significantly reduces the computational cost caused by the MCS and optimization process.In the proposed method,the number of function evaluations is equal to one plus the sum of the subintervals of all of the variables.The efficiency and accuracy of the proposed method are verified by five examples.The results show that the proposed method is not only efficient but also accurate.
基金This research was funded by the National Natural Science Foundation of China,No.61802010Hundred-Thousand-Ten Thousand Talents Project of Beijing No.2020A28+1 种基金National Social Science Fund of China,No.19BGL184Beijing Excellent Talent Training Support Project for Young Top-Notch Team No.2018000026833TD01 and Academic Research Projects of Beijing Union University,No.ZK30202103。
文摘Underwater sensor networks have important application value in the fields of water environment data collection,marine environment monitoring and so on.It has some characteristics such as low available bandwidth,large propagation delays and limited energy,which bring new challenges to the current researches.The research on coverage control of underwater sensor networks is the basis of other related researches.A good sensor node coverage control method can effectively improve the quality of water environment monitoring.Aiming at the problem of high dynamics and uncertainty of monitoring targets,the random events level are divided into serious events and general events.The sensors are set to sense different levels of events and make different responses.Then,an event-driven optimization algorithm for determining sensor target location based on self-organization map is proposed.Aiming at the problem of limited energy of underwater sensor nodes,considering the moving distance,coverage redundancy and residual energy of sensor nodes,an underwater sensor movement control algorithm based on residual energy probability is proposed.The simulation results show that compared with the simple movement algorithm,the proposed algorithm can effectively improve the coverage and life cycle of the sensor networks,and realize real-time monitoring of the water environment.
基金This research was funded by the National Natural Science Foundation of China,No.61802010Hundred-Thousand-Ten Thousand Talents Project of Beijing No.2020A28+1 种基金National Social Science Fund of China,No.19BGL184Beijing Excellent Talent Training Support Project for Young Top-Notch Team No.2018000026833TD01.
文摘Wireless sensor networks(WSN)can be used in many fields.In wireless sensor networks,sensor nodes transmit data in multi hop mode.The large number of hops required by data transmission will lead to unbalanced energy consumption and large data transmission delay of the whole network,which greatly affects the invulnerability of the network.Therefore,an optimal deployment of heterogeneous nodes(ODHN)algorithm is proposed to enhance the invulnerability of the wireless sensor networks.The algorithm combines the advantages of DEEC(design of distributed energy efficient clustering)clustering algorithm and BAS(beetle antenna search)optimization algorithm to find the globally optimal deployment locations of heterogeneous nodes.Then,establish a shortcut to communicate with sink nodes through heterogeneous nodes.Besides,considering the practical deployment operation,we set the threshold of the mobile location of heterogeneous nodes,which greatly simplifies the deployment difficulty.Simulation results show that compared with traditional routing protocols,the proposed algorithm can make the network load more evenly,and effectively improve energy-utilization and the fault tolerance of the whole network,which can greatly improve the invulnerability of the wireless sensor networks.
基金This research was funded by the National Natural Science Foundation of China,No.61802010Hundred-Thousand-Ten Thousand Talents Project of Beijing No.2020A28+2 种基金National Social Science Fund of China,No.19BGL184Beijing Excellent Talent Training Support Project for Young Top-Notch Team No.2018000026833TD01Academic Research Projects of Beijing Union University,No.ZK30202103.
文摘Wireless Sensor Network(WSN)is an important part of the Internet of Things(IoT),which are used for information exchange and communication between smart objects.In practical applications,WSN lifecycle can be influenced by the unbalanced distribution of node centrality and excessive energy consumption,etc.In order to overcome these problems,a heterogeneous wireless sensor network model with small world characteristics is constructed to balance the centrality and enhance the invulnerability of the network.Also,a new WSN centrality measurement method and a new invulnerability measurement model are proposed based on the WSN data transmission characteristics.Simulation results show that the life cycle and data transmission volume of the network can be improved with a lower network construction cost,and the invulnerability of the network is effectively enhanced.
基金This research was funded by the National Natural Science Foundation of China(Grant No.61802010)National Social Science Fund of China(Grant No.19BGL184)+1 种基金Beijing Excellent Talent Training Support Project for Young Top-Notch Team(Grant No.2018000026833TD01)and Hundred-Thousand-Ten Thousand Talents Project of Beijing(Grant No.2020A28).
文摘Water quality sensor networks are promising tools for the exploration of oceans.Some key areas need to be monitored effectively.Water quality sensors are deployed randomly or uniformly,however,and understanding how to deploy sensor nodes reasonably and realize effective monitoring of key areas on the basis of monitoring the whole area is an urgent problem to be solved.Additionally,energy is limited in water quality sensor networks.When moving sensor nodes,we should extend the life cycle of the sensor networks as much as possible.In this study,sensor nodes in non-key monitored areas are moved to key areas.First,we used the concentric circle method to determine the mobile sensor nodes and the target locations.Then,we determined the relationship between the mobile sensor nodes and the target locations according to the energy matrix.Finally,we calculated the shortest moving path according to the Floyd algorithm,which realizes the redeployment of the key monitored area.The simulation results showed that,compared with the method of direct movement,the proposed method can effectively reduce the energy consumption and save the network adjustment time based on the effective coverage of key areas.
基金This research was funded by the National Natural Science Foundation of China(Grant No.61802010)Hundred-Thousand-Ten-Thousand Talents Project of Beijing(Grant No.2020A28)+1 种基金National Social Science Fund of China(Grant No.19BGL184)Beijing Excellent Talent Training Support Project for Young Top-Notch Team(Grant No.2018000026833TD01).
文摘Water quality sensor networks are widely used in water resource monitoring.However,due to the fact that the energy of these networks cannot be supplemented in time,it is necessary to study effective routing protocols to extend their lifecycle.To address the problem of limited resources,a routing optimization algorithm based on a small-world network model is proposed.In this paper,a small-world network model is introduced for water quality sensor networks,in which the short average path and large clustering coefficient of the model are used to construct a super link.A short average path can reduce the network’s energy consumption,and a large coefficient can improve its fault-tolerance ability.However,the energy consumption of the relay nodes near the heterogeneous node is too great,and as such the energy threshold and non-uniform clustering are constructed to improve the lifecycle of the network.Simulation results show that,compared with the low-energy adaptive clustering hierarchy routing algorithm and the best sink location clustering heterogeneous network routing algorithm,the proposed improved routing model can effectively enhance the energy-utilization.The lifecycle of the network can be extended and the data transmission amount can be greatly increased.
基金This study was supported by the National Natural Science Foundation of China(31770568,32071544)the“Light of West China”Program of the Chinese Academy of Sciences(2019XBZG_XBQNZG_A_003)the National Major Science and Technology Projects of China(2018YFC0507206).
文摘Background:Spatial variation of land cover can result in the changes of community similarities and biotic homog-enization,whereby the increasing similarity would reduce the adaptive capacity of biotic assemblages to further disturbance,and degenerate ecosystem services they offer.However,it remains scarce to integrate multidimensional diversity for unveiling how variations in land cover may influence the patterns and processes of biotic homogeniza-tion in the Anthropocene.In this study,we examined how spatial variation of land cover could alter taxonomic,phy-logenetic and functional homogenization of bird communities simultaneously in a compound ecosystem of Zoige Marsh on the eastern Qinghai-Tibetan Plateau.Acting as the largest alpine marsh and peatland in the world,Zoige Marsh has undergone great changes in the land cover pattern due to climate change and anthropogenic activities.Methods:We conducted transect surveys for bird communities over six years(2014‒2019)during breeding sea-sons in four main land cover types(meadow,woodland,village and marsh),representing the spatial variation of land covers in the study area.We compared multidimensional diversity(taxonomic,phylogenetic and functional diver-sity)among land covers to assess the effects of spatial variation in land cover type on bird communities,particularly whether this variation has homogenized biotic communities.Results:Bird communities during breeding seasons were different and complementary in the four land covers.Taxonomic,phylogenetic and functional similarities were significantly lower in meadow than in the other three types,i.e.woodland,village and marsh.However,when we controlled for the effects of taxonomic similarities,the pattern of phylogenetic similarities almost reversed,with the highest standardized effect size(SES)phylogenetic similarity in meadow;and we found no significant difference in SES functional similarity among land covers.Conclusions:Our results suggest that spatial variation of land cover can play a crucial role in regulating multiple dimensions of bird diversity in Zoige Marsh.The findings indicate that taxonomic,phylogenetic and functional homogenization of bird communities may differently response to the variation of land covers.It thus highlights not only the relative roles of different land covers in maintaining biodiversity and community structures of birds,but also the urgency of retarding ecosystem degradations on the eastern Qinghai-Tibetan Plateau.
