Dispersals,colonisation,immigration and population assimilation or replacement are fundamental themes in the Palaeolithic record of East Asia.Some of these issues can be studied within a biogeographic framework that e...Dispersals,colonisation,immigration and population assimilation or replacement are fundamental themes in the Palaeolithic record of East Asia.Some of these issues can be studied within a biogeographic framework that explains why and how the distribution of hominin species changed over time and space in response to climatic and environmental change.Because hominins(and especially humans)can change their behaviour through technical,social and cognitive developments,biogeographic models also have to incorporate this factor when investigating dispersals.This is particularly important with the dispersals in East Asia by Homo sapiens into rainforests,across open sea to off-shore islands,to the Arctic and the highest parts of the Tibetan Plateau.This paper suggests how hominin and human dispersals in East Asia might be investigated by using a biogeographic framework that can incorporate changes in hominin adaptability and behaviour.展开更多
Dispersal is an important life history trait with signifcant consequences for spatially structured populations,as the exchange of individuals between habitat patches is crucial for maintaining metapopulation connectiv...Dispersal is an important life history trait with signifcant consequences for spatially structured populations,as the exchange of individuals between habitat patches is crucial for maintaining metapopulation connectivity.In this study,we used a long-term data set(2005–2023)to describe dispersal patterns in a patchy population of the Western Yellow Wagtail Motacilla fava within a large(approximately 1,300 km2)study area in the boreal zone of European Russia.We quantifed dispersal distances for birds that dispersed outside their natal or breeding habitat patches and applied a multistate capture–recapture approach to estimate natal and breeding dispersal probabilities.Of 395 adult wagtails and 1,610 nestlings ringed,3%of birds ringed as adults and 3%of birds ringed as nestlings were resighted outside their natal or breeding patches.The probability of natal dispersal(0.29±0.05)was signifcantly higher than the probability of breeding dispersal(0.05±0.01).The median natal dispersal distances(2.8 km for males,3.9 km for females)were the same as the median breeding dispersal distances(2.7 km for males,3.9 km for females).We did not fnd a signifcant effect of the fedging date on either the natal dispersal distance or the natal dispersal probability.Similarly,we did not fnd a signifcant effect of the previous reproductive success on either the breeding dispersal distance or the breeding dispersal probability.Our results indicate that strong breeding site fdelity and short-distance natal dispersal are the dominant dispersal strategies in a patchy population of the western yellow wagtail.展开更多
Natal dispersal is a critical trait for individual ftness and the viability,structure,and genetic identity of populations.However,there is a pronounced information gap for large and long-lived species due to the diffc...Natal dispersal is a critical trait for individual ftness and the viability,structure,and genetic identity of populations.However,there is a pronounced information gap for large and long-lived species due to the diffculty of monitoring individuals at appropriate spatio-temporal scales.Here we study how individual traits and social and environmental characteristics infuence natal dispersal decisions of griffon vultures(Gypsfulvus)using long-term(30 years)monitoring of a large number of individuals marked as nestlings in Spain.Our results show a strong philopatryin both sexes,with some individuals recruiting as breeders on the same cliffs,and even the same nests,where they were born.This philopatrictendency was modulated by the effect of conspecifc density on individual parameters and emphasized the importance of conspecifc attraction and changes in food availability that may have infuenced the increment in colony size and the colonization of new areas.Although furtherresearch is needed considering smaller colonies and more isolated population nuclei,our results highlight the importance of long-term studieson long-lived species to understand the factors that determine their population dynamics and their relationship with anthropogenic activities,whose effects should be predicted and managed using conservation criteria.展开更多
Mimetic seeds attract birds to disperse seeds mainly by mimicking fleshy fruits or arillate seeds,however,they provide little nutritive reward for bird dispersers.The key characteristics of mimetic seeds are conspicuo...Mimetic seeds attract birds to disperse seeds mainly by mimicking fleshy fruits or arillate seeds,however,they provide little nutritive reward for bird dispersers.The key characteristics of mimetic seeds are conspicuous seed color,hard seed coat,certain toxic secondary metabolites,and perhaps smooth waxy layer.In this review,we discuss the global distribution of mimetic seeds,the interaction of mimetic seeds with bird dispersers,and secondary metabolites that underlie key characteristics of mimetic seeds.Mimetic-seed species mainly occur in the tropics,with large numbers distributed along coastal areas.The interaction between mimetic-seed species and bird dispersers can be antagonistic,mutualistic,or both.These interactions are generally established by conspicuous visual cues and hard tactile cues from mimetic seeds.The formation and variation of key characteristics of mimetic seeds may contribute to the metabolism of several kind of secondary compounds.Here,we also discuss mimetic-seed dispersal in the context of an evolutionary game,and propose several aspects of mimetic-seed dispersal that remain unstudied.While this review is based on preliminary findings and does not account for other potential influencing factors such as climate,it is expected to contribute to an improved understanding of mimetic-seed dispersal.展开更多
The formation of pantropical intercontinental disjunction(PID)in plants has generally been attributed to vicariance,boreotropical migration,and long-distance dispersal.However,this pattern has primarily been examined ...The formation of pantropical intercontinental disjunction(PID)in plants has generally been attributed to vicariance,boreotropical migration,and long-distance dispersal.However,this pattern has primarily been examined in herbs,shrubs,and trees,and less commonly studied in interlayer plant taxa.Here we examined evolutionary processes that resulted in the PID of a pantropical woody liana,Uncaria(Rubiaceae).We first constructed a comprehensive phylogeny by employing 73 plastid protein-coding sequences from 29 accessions of Uncaria(including 16 newly sequenced)from different continents.We then inferred divergence time,history and ecological niche evolution of this genus.Our results showed that Uncaria consisted of four well-supported clades that belonged to two geographically distinct lineages:the Asia-Oceania lineage and the Afro-Neotropical lineage.Biogeographic reconstruction showed this genus likely originated in Asia during the early Miocene(ca.19.03 Ma)and the Middle Miocene Climatic Optimum may have triggered the early diversification of Uncaria.Due to its recent origin and small seeds with long wings,wind or water-mediated long-distance dispersal may have contributed to the distribution of Uncaria in tropical Oceania(via stepping-stone dispersal)and tropical Africa and America(by transoceanic dispersal).Our findings also indicate that diversification of Uncaria was primarily driven by ecological niche divergence,particularly climatic factors.Our study emphasizes the dual role of climatic niche divergence and long-distance dispersal in shaping the PID of Uncaria,providing references for many other extant lineages with similar distributions.展开更多
Elucidating the mechanisms underlying community assembly remains a central question in community ecology,especially in aquatic ecosystems disrupted by human activities.Understanding the causes and consequences of comm...Elucidating the mechanisms underlying community assembly remains a central question in community ecology,especially in aquatic ecosystems disrupted by human activities.Understanding the causes and consequences of community responses to changing environment is essential for revealing the ecological effects of anthropogenic disturbances and proposing practical strategies for ecological restoration.While stochastic dispersal and species sorting are known to influence local biological communities,most studies have focused on horizontal dispersal,often neglecting the vertical exchange of organisms between planktonic and sedimentary communities when studying stochastic dispersal.We used a highly disturbed urban river in Beijing as a model system to investigate the relative roles of stochastic dispersal versus species sorting driven by local pollution,as well as two components of stochastic dispersal,vertical exchange and horizontal dispersal,in structuring local bacterial communities.Our integrated analyses of planktonic and sedimentary bacterial communities revealed that,despite different spatial patterns along the river,both types of bacterial communities were primarily shaped by stochastic dispersal processes rather than species sorting influenced by the environmental gradient.Notably,in addition to the effect of horizontal dispersal along the river,the vertical exchange between planktonic and sedimentary bacterial communities significantly contributed to the formation of local communities.These findings suggest that both vertical exchange and horizontal dispersal should be considered when assessing the role of stochastic dispersal in shaping local community structure in microbial communities.展开更多
A predator-prey model with prey dispersal and Holling type-Ⅱ functional response is investigated.In this model,the time delay due to the gestation of the predator and stagestructure for the predator are considered.By...A predator-prey model with prey dispersal and Holling type-Ⅱ functional response is investigated.In this model,the time delay due to the gestation of the predator and stagestructure for the predator are considered.By analyzing the corresponding characteristic equations,the local stability of each of the nonnegative equilibria is discussed.The existence of Hopf bifurcations at the positive equilibrium is established.By using Lyapunov functionals and LaSalle’s invariance principle,sufficient conditions are obtained for the global stability of the positive equilibrium,the nonnegative boundary equilibrium and the trivial equilibrium of the model,respectively.Numerical simulations are carried out to illustrate the main results.展开更多
This paper examines an epidemic predator-prey model with prey dispersal and Holling type-II functional response. In this model, it is assumed that the predator population suffers a transmissible disease. By analyzing ...This paper examines an epidemic predator-prey model with prey dispersal and Holling type-II functional response. In this model, it is assumed that the predator population suffers a transmissible disease. By analyzing the corresponding characteristic equations, the local stability of each of feasible equilibria and the existence of Hopf bifurcations at the coexistence equilibrium is addressed. Using Lyapunov functionals and LaSalle's invariance principle, we obtained the sufficient conditions for the global stability of the trivial equilibrium, the predator-extinction equilibrium, the disease-free equilibrium and the coexistence equilibrium, respectively. The paper also includes numerical simulations to illustrate the analytical results.展开更多
It is well-known that the propagation phenomena of nonlocal dispersal equations have been extensively studied,and the known results on the interface dynamics of this equation are under the compactly supported initial ...It is well-known that the propagation phenomena of nonlocal dispersal equations have been extensively studied,and the known results on the interface dynamics of this equation are under the compactly supported initial value.Moreover,there was no explicit formula regarding the interface due to the peculiarity of nonlocal dispersal operators.Anatural question is whether it is possible to provide a precise characterization of the interface with respect to small parameter for the general initial values(including exponentially bounded and unbounded).This paper is concerned with the interface dynamics of the nonlocal dispersal equation with scaling parameter.For the exponentially bounded initial value,by choosing the hyperbolic scaling,we show that at a very small time,the interface is confined within a generated layer whose thickness is at most O(√ɛ|ln ɛ|),,and subsequently,the interface propagates at a linear speed determined by the decay rate of initial value.For a class of exponentially unbounded initial value,by introducing the nonlinear scaling based on the decay of initial value,we deduce the corresponding Hamilton-Jacobi equation and describe precisely the propagation of the interface,which provides a superlinear speed of the interface.The investigation of the interface dynamics under different scaling reflects multiplex propagation modes in spatial dynamics and provides a new perspective on the wave propagation in nonlocal dispersal equations.展开更多
To assess the population development of submerged plant species in disturbed lake ecosystems,we need to better understand the genetic diversity and spatial genetic structure at a fine scale,as well as the impact of di...To assess the population development of submerged plant species in disturbed lake ecosystems,we need to better understand the genetic diversity and spatial genetic structure at a fine scale,as well as the impact of disturbances on the populations.Caohai Lake,in southwest China,is a suitable natural sampling lake because of its abundance of submerged plants and the intense human disturbance.Three widely distributed species,Potamogeton lucens,Ceratophyllum demersum,and Myriophyllum spicatum,were sampled;the spatial position of each individual was recorded in two-dimensional coordinates;and the species were analyzed genetically using microsatellite markers.Among the species studied,M.spicatum exhibited the highest genetic and clonal diversities.All P.lucens subpopulations but one showed a significant fine-scale spatial genetic structure(FSGS),which may result from the limited gene dispersal.However,M.spicatum and C.demersum,with a relatively large distance of gene dispersal,had no significant FSGS.The FSGS pattern of P.lucens at the dock site with intense boat disturbance was significantly different from that at other sites.Our results imply that the FSGS of submerged plants is affected by many factors including seed dispersal,vegetative reproduction and disturbance from birds and boats.Most subpopulations of the three species hadσ_(sex)^(2)/σ_(veg)^(2)values greater than one,implying that the sexual dispersal contributes more than vegetative dispersal to total gene dispersal.Therefore,it is worth paying attention to the importance of seed dispersal for population development of submerged plants in lake ecosystems.展开更多
Aim To study fuel dispersion in fuel air explosive(FAE) and computational ways of fuel dispersion velocity in the near area. Methods\ The dispersion process of fuel in FAE was analyzed by the use of results measured ...Aim To study fuel dispersion in fuel air explosive(FAE) and computational ways of fuel dispersion velocity in the near area. Methods\ The dispersion process of fuel in FAE was analyzed by the use of results measured with KODAK EKTAPRO EM Motion Analyzer and setting up mechanical models. Results\ Computational methods for fuel dispersion velocity in the acceleration stage is given and taken as a base for the study of fuel dispersion in the intermediate and the far area. Conclusion\ When the fuel flow velocity is higher than that of the explosion gas in the center cavity, the fuel divides with the explosion gas and its velocity of flow reaches a maximum. The acceleration stage ends at that time. The fuel dispersion velocity at this time is the initial conditions for numeral analyses of dispersion process in the intermediate and far areas.展开更多
Scatter hoarding by corvids （crows, jays, magpies, and nutcrackers） provides seed dispersal for many large-seeded plants, including oaks and pines. When hoarding seeds, corvids often choose nonrandom locations throu...Scatter hoarding by corvids （crows, jays, magpies, and nutcrackers） provides seed dispersal for many large-seeded plants, including oaks and pines. When hoarding seeds, corvids often choose nonrandom locations throughout the landscape, resulting in differential survival of seeds. In the context of habitat restoration, such disproportional storing of seeds in areas suitable for germin- ation and establishment can accelerate expansion and recovery of large-seeded tree populations and their associated ecosystems. Here, we investigate the spatial preferences of island scrub jays Aphelocoma insularis during scatter hoarding of acorns （Quercus spp.） on Santa Cruz Island. We use a large behavioral data set on the birds＇ behavior in combination with seedling surveys and spatial analysis to determine whether 1） island scrub jays disproportionally cache seeds in specific habitat types, and 2） whether the preferred habitat type is suitable for oak regeneration. Our results show that the jays nonrandomly cache acorns across the landscape; they use chaparral and coastal sage scrub disproportionally while avoiding open and grassy areas. The areas used most often for caching were also the areas with the highest oak seedling densities. We discuss the potential role of these findings for the recovery of Santa Cruz Island＇s oak habitat since the 1980s.展开更多
Strategies for achieving high-energy-density lithium-ion batteries include using high-capacity materials such as high-nickel NCM,increasing the active material content in the electrode by utilizing high-conductivity c...Strategies for achieving high-energy-density lithium-ion batteries include using high-capacity materials such as high-nickel NCM,increasing the active material content in the electrode by utilizing high-conductivity carbon nanotubes(CNT)conductive materials,and electrode thickening.However,these methods are still limited due to the limitation in the capacity of high-nickel NCM,aggregation of CNT conductive materials,and nonuniform material distribution of thick-film electrodes,which ultimately damage the mechanical and electrical integrity of the electrode,leading to a decrease in electrochemical performance.Here,we present an integrated binder-CNT composite dispersion solution to realize a high-solids-content(>77 wt%)slurry for high-mass-loading electrodes and to mitigate the migration of binder and conductive additives.Indeed,the approach reduces solvent usage by approximately 30%and ensures uniform conductive additive-binder domain distribution during electrode manufacturing,resulting in improved coating quality and adhesive strength for high-mass-loading electrodes(>12 mAh cm^(−2)).In terms of various electrode properties,the presented electrode showed low resistance and excellent electrochemical properties despite the low CNT contents of 0.6 wt%compared to the pristine-applied electrode with 0.85 wt%CNT contents.Moreover,our strategy enables faster drying,which increases the coating speed,thereby offering potential energy savings and supporting carbon neutrality in wet-based electrode manufacturing processes.展开更多
文摘Dispersals,colonisation,immigration and population assimilation or replacement are fundamental themes in the Palaeolithic record of East Asia.Some of these issues can be studied within a biogeographic framework that explains why and how the distribution of hominin species changed over time and space in response to climatic and environmental change.Because hominins(and especially humans)can change their behaviour through technical,social and cognitive developments,biogeographic models also have to incorporate this factor when investigating dispersals.This is particularly important with the dispersals in East Asia by Homo sapiens into rainforests,across open sea to off-shore islands,to the Arctic and the highest parts of the Tibetan Plateau.This paper suggests how hominin and human dispersals in East Asia might be investigated by using a biogeographic framework that can incorporate changes in hominin adaptability and behaviour.
基金supported by the Russian Science Foundation(grant number 23-24-00042).
文摘Dispersal is an important life history trait with signifcant consequences for spatially structured populations,as the exchange of individuals between habitat patches is crucial for maintaining metapopulation connectivity.In this study,we used a long-term data set(2005–2023)to describe dispersal patterns in a patchy population of the Western Yellow Wagtail Motacilla fava within a large(approximately 1,300 km2)study area in the boreal zone of European Russia.We quantifed dispersal distances for birds that dispersed outside their natal or breeding habitat patches and applied a multistate capture–recapture approach to estimate natal and breeding dispersal probabilities.Of 395 adult wagtails and 1,610 nestlings ringed,3%of birds ringed as adults and 3%of birds ringed as nestlings were resighted outside their natal or breeding patches.The probability of natal dispersal(0.29±0.05)was signifcantly higher than the probability of breeding dispersal(0.05±0.01).The median natal dispersal distances(2.8 km for males,3.9 km for females)were the same as the median breeding dispersal distances(2.7 km for males,3.9 km for females).We did not fnd a signifcant effect of the fedging date on either the natal dispersal distance or the natal dispersal probability.Similarly,we did not fnd a signifcant effect of the previous reproductive success on either the breeding dispersal distance or the breeding dispersal probability.Our results indicate that strong breeding site fdelity and short-distance natal dispersal are the dominant dispersal strategies in a patchy population of the western yellow wagtail.
基金partially funded through projects PID2019-109685GB-I00,CGL2007-61395,CGL2010-15726,and CGL2013-42451-P,of the Spanish Ministry of Science and Innovation.
文摘Natal dispersal is a critical trait for individual ftness and the viability,structure,and genetic identity of populations.However,there is a pronounced information gap for large and long-lived species due to the diffculty of monitoring individuals at appropriate spatio-temporal scales.Here we study how individual traits and social and environmental characteristics infuence natal dispersal decisions of griffon vultures(Gypsfulvus)using long-term(30 years)monitoring of a large number of individuals marked as nestlings in Spain.Our results show a strong philopatryin both sexes,with some individuals recruiting as breeders on the same cliffs,and even the same nests,where they were born.This philopatrictendency was modulated by the effect of conspecifc density on individual parameters and emphasized the importance of conspecifc attraction and changes in food availability that may have infuenced the increment in colony size and the colonization of new areas.Although furtherresearch is needed considering smaller colonies and more isolated population nuclei,our results highlight the importance of long-term studieson long-lived species to understand the factors that determine their population dynamics and their relationship with anthropogenic activities,whose effects should be predicted and managed using conservation criteria.
基金supported by the Yunnan Ten Thousand Talents Plan Young&Elite Talents Project(YNWR-QNBJ-2018-017)the National Natural Science Foundation of China(32371564)+2 种基金the Key Project of Basic Research of Yunnan Province,China(202101AS070035202301AS070001)to G.ChenYunnan Provincial Science and Technology Talent and Platform Plan(202305AM070005).
文摘Mimetic seeds attract birds to disperse seeds mainly by mimicking fleshy fruits or arillate seeds,however,they provide little nutritive reward for bird dispersers.The key characteristics of mimetic seeds are conspicuous seed color,hard seed coat,certain toxic secondary metabolites,and perhaps smooth waxy layer.In this review,we discuss the global distribution of mimetic seeds,the interaction of mimetic seeds with bird dispersers,and secondary metabolites that underlie key characteristics of mimetic seeds.Mimetic-seed species mainly occur in the tropics,with large numbers distributed along coastal areas.The interaction between mimetic-seed species and bird dispersers can be antagonistic,mutualistic,or both.These interactions are generally established by conspicuous visual cues and hard tactile cues from mimetic seeds.The formation and variation of key characteristics of mimetic seeds may contribute to the metabolism of several kind of secondary compounds.Here,we also discuss mimetic-seed dispersal in the context of an evolutionary game,and propose several aspects of mimetic-seed dispersal that remain unstudied.While this review is based on preliminary findings and does not account for other potential influencing factors such as climate,it is expected to contribute to an improved understanding of mimetic-seed dispersal.
基金funded equally by grants from the National Natural Science Foundation of China(32322006 and 32100187)the Second Tibetan Plateau Scientific Expedition and Research(STEP)program(2024QZKK0200)+5 种基金by the Key Projects of the Joint Fund of the National Natural Science Foundation of China(U23A20149)the Key R&D Program of Yunnan Province(202103AF140005 and 202101BC070002)the Yunnan Provincial Science and Technology Talent and Platform Plan(202305AM070005)the Key Specialized Research and Development Breakthrough Program in Henan Province(232102110237)the Natural Science Foundation of Henan Province(242300421572)the Strategic Biological Resources Capacity Building Project of Chinese Academy of Sciences(KFJ-BRP-017-08).
文摘The formation of pantropical intercontinental disjunction(PID)in plants has generally been attributed to vicariance,boreotropical migration,and long-distance dispersal.However,this pattern has primarily been examined in herbs,shrubs,and trees,and less commonly studied in interlayer plant taxa.Here we examined evolutionary processes that resulted in the PID of a pantropical woody liana,Uncaria(Rubiaceae).We first constructed a comprehensive phylogeny by employing 73 plastid protein-coding sequences from 29 accessions of Uncaria(including 16 newly sequenced)from different continents.We then inferred divergence time,history and ecological niche evolution of this genus.Our results showed that Uncaria consisted of four well-supported clades that belonged to two geographically distinct lineages:the Asia-Oceania lineage and the Afro-Neotropical lineage.Biogeographic reconstruction showed this genus likely originated in Asia during the early Miocene(ca.19.03 Ma)and the Middle Miocene Climatic Optimum may have triggered the early diversification of Uncaria.Due to its recent origin and small seeds with long wings,wind or water-mediated long-distance dispersal may have contributed to the distribution of Uncaria in tropical Oceania(via stepping-stone dispersal)and tropical Africa and America(by transoceanic dispersal).Our findings also indicate that diversification of Uncaria was primarily driven by ecological niche divergence,particularly climatic factors.Our study emphasizes the dual role of climatic niche divergence and long-distance dispersal in shaping the PID of Uncaria,providing references for many other extant lineages with similar distributions.
基金supported by the National Natural Science Foundation of China(No.32471608)the Open Project of Key Laboratory of Environmental Biotechnology,CAS(No.kf2020002)Yunnan Collaborative Innovation Center for Plateau Lake Ecology and Environmental Health.
文摘Elucidating the mechanisms underlying community assembly remains a central question in community ecology,especially in aquatic ecosystems disrupted by human activities.Understanding the causes and consequences of community responses to changing environment is essential for revealing the ecological effects of anthropogenic disturbances and proposing practical strategies for ecological restoration.While stochastic dispersal and species sorting are known to influence local biological communities,most studies have focused on horizontal dispersal,often neglecting the vertical exchange of organisms between planktonic and sedimentary communities when studying stochastic dispersal.We used a highly disturbed urban river in Beijing as a model system to investigate the relative roles of stochastic dispersal versus species sorting driven by local pollution,as well as two components of stochastic dispersal,vertical exchange and horizontal dispersal,in structuring local bacterial communities.Our integrated analyses of planktonic and sedimentary bacterial communities revealed that,despite different spatial patterns along the river,both types of bacterial communities were primarily shaped by stochastic dispersal processes rather than species sorting influenced by the environmental gradient.Notably,in addition to the effect of horizontal dispersal along the river,the vertical exchange between planktonic and sedimentary bacterial communities significantly contributed to the formation of local communities.These findings suggest that both vertical exchange and horizontal dispersal should be considered when assessing the role of stochastic dispersal in shaping local community structure in microbial communities.
基金Supported by the Social Science Foundation of Hebei Province(HB23TJO03)。
文摘A predator-prey model with prey dispersal and Holling type-Ⅱ functional response is investigated.In this model,the time delay due to the gestation of the predator and stagestructure for the predator are considered.By analyzing the corresponding characteristic equations,the local stability of each of the nonnegative equilibria is discussed.The existence of Hopf bifurcations at the positive equilibrium is established.By using Lyapunov functionals and LaSalle’s invariance principle,sufficient conditions are obtained for the global stability of the positive equilibrium,the nonnegative boundary equilibrium and the trivial equilibrium of the model,respectively.Numerical simulations are carried out to illustrate the main results.
基金Supported by the Social Science Foundation of Hebei Province(Grant No.HB23TJ003)the Science Research Project of Hebei Education Department(Grant No.BJK2024197)。
文摘This paper examines an epidemic predator-prey model with prey dispersal and Holling type-II functional response. In this model, it is assumed that the predator population suffers a transmissible disease. By analyzing the corresponding characteristic equations, the local stability of each of feasible equilibria and the existence of Hopf bifurcations at the coexistence equilibrium is addressed. Using Lyapunov functionals and LaSalle's invariance principle, we obtained the sufficient conditions for the global stability of the trivial equilibrium, the predator-extinction equilibrium, the disease-free equilibrium and the coexistence equilibrium, respectively. The paper also includes numerical simulations to illustrate the analytical results.
基金partially supported by the NSF of China(12271226)partially supported by the NSF of China(12201434)+4 种基金the NSF of Gansu Province of China(21JR7RA537)the NSF of Gansu Province of China(21JR7RA535)the Fundamental Research Funds for the Central Universities(lzujbky-2021-kb15)partially supported by the NSF of China(12371170)the R&D Program of Beijing Municipal Education Commission(KM202310028017)。
文摘It is well-known that the propagation phenomena of nonlocal dispersal equations have been extensively studied,and the known results on the interface dynamics of this equation are under the compactly supported initial value.Moreover,there was no explicit formula regarding the interface due to the peculiarity of nonlocal dispersal operators.Anatural question is whether it is possible to provide a precise characterization of the interface with respect to small parameter for the general initial values(including exponentially bounded and unbounded).This paper is concerned with the interface dynamics of the nonlocal dispersal equation with scaling parameter.For the exponentially bounded initial value,by choosing the hyperbolic scaling,we show that at a very small time,the interface is confined within a generated layer whose thickness is at most O(√ɛ|ln ɛ|),,and subsequently,the interface propagates at a linear speed determined by the decay rate of initial value.For a class of exponentially unbounded initial value,by introducing the nonlinear scaling based on the decay of initial value,we deduce the corresponding Hamilton-Jacobi equation and describe precisely the propagation of the interface,which provides a superlinear speed of the interface.The investigation of the interface dynamics under different scaling reflects multiplex propagation modes in spatial dynamics and provides a new perspective on the wave propagation in nonlocal dispersal equations.
基金Supported by the National Natural Science Foundation of China(No.31600325)the Self-determined Research Funds of the Central China Normal University(CCNU)from the Colleges’Basic Research and Operation of MOE(No.CCNU20TS022)。
文摘To assess the population development of submerged plant species in disturbed lake ecosystems,we need to better understand the genetic diversity and spatial genetic structure at a fine scale,as well as the impact of disturbances on the populations.Caohai Lake,in southwest China,is a suitable natural sampling lake because of its abundance of submerged plants and the intense human disturbance.Three widely distributed species,Potamogeton lucens,Ceratophyllum demersum,and Myriophyllum spicatum,were sampled;the spatial position of each individual was recorded in two-dimensional coordinates;and the species were analyzed genetically using microsatellite markers.Among the species studied,M.spicatum exhibited the highest genetic and clonal diversities.All P.lucens subpopulations but one showed a significant fine-scale spatial genetic structure(FSGS),which may result from the limited gene dispersal.However,M.spicatum and C.demersum,with a relatively large distance of gene dispersal,had no significant FSGS.The FSGS pattern of P.lucens at the dock site with intense boat disturbance was significantly different from that at other sites.Our results imply that the FSGS of submerged plants is affected by many factors including seed dispersal,vegetative reproduction and disturbance from birds and boats.Most subpopulations of the three species hadσ_(sex)^(2)/σ_(veg)^(2)values greater than one,implying that the sexual dispersal contributes more than vegetative dispersal to total gene dispersal.Therefore,it is worth paying attention to the importance of seed dispersal for population development of submerged plants in lake ecosystems.
文摘Aim To study fuel dispersion in fuel air explosive(FAE) and computational ways of fuel dispersion velocity in the near area. Methods\ The dispersion process of fuel in FAE was analyzed by the use of results measured with KODAK EKTAPRO EM Motion Analyzer and setting up mechanical models. Results\ Computational methods for fuel dispersion velocity in the acceleration stage is given and taken as a base for the study of fuel dispersion in the intermediate and the far area. Conclusion\ When the fuel flow velocity is higher than that of the explosion gas in the center cavity, the fuel divides with the explosion gas and its velocity of flow reaches a maximum. The acceleration stage ends at that time. The fuel dispersion velocity at this time is the initial conditions for numeral analyses of dispersion process in the intermediate and far areas.
文摘Scatter hoarding by corvids （crows, jays, magpies, and nutcrackers） provides seed dispersal for many large-seeded plants, including oaks and pines. When hoarding seeds, corvids often choose nonrandom locations throughout the landscape, resulting in differential survival of seeds. In the context of habitat restoration, such disproportional storing of seeds in areas suitable for germin- ation and establishment can accelerate expansion and recovery of large-seeded tree populations and their associated ecosystems. Here, we investigate the spatial preferences of island scrub jays Aphelocoma insularis during scatter hoarding of acorns （Quercus spp.） on Santa Cruz Island. We use a large behavioral data set on the birds＇ behavior in combination with seedling surveys and spatial analysis to determine whether 1） island scrub jays disproportionally cache seeds in specific habitat types, and 2） whether the preferred habitat type is suitable for oak regeneration. Our results show that the jays nonrandomly cache acorns across the landscape; they use chaparral and coastal sage scrub disproportionally while avoiding open and grassy areas. The areas used most often for caching were also the areas with the highest oak seedling densities. We discuss the potential role of these findings for the recovery of Santa Cruz Island＇s oak habitat since the 1980s.
基金supported by the National Research Foundation of Korea(NRF)grant funded by the Korea government(MSIT)(No.2022M3H4A6A0103720142)the National Research Council of Science&Technology(NST)grant by the Korea government(MSIT)(No.GTL24011-000)+1 种基金the Technology Innovation Program(RS-2024-00404165)through the Korea Planning&Evaluation Institute of Industrial Technology(KEIT)funded by the Ministry of Trade,Industry&Energy(MOTIE,Korea)supported by the Samsung SDI Co.Ltd.and the Korea Institute of Science and Technology(KIST)institutional program(2E33942,2E3394B)。
文摘Strategies for achieving high-energy-density lithium-ion batteries include using high-capacity materials such as high-nickel NCM,increasing the active material content in the electrode by utilizing high-conductivity carbon nanotubes(CNT)conductive materials,and electrode thickening.However,these methods are still limited due to the limitation in the capacity of high-nickel NCM,aggregation of CNT conductive materials,and nonuniform material distribution of thick-film electrodes,which ultimately damage the mechanical and electrical integrity of the electrode,leading to a decrease in electrochemical performance.Here,we present an integrated binder-CNT composite dispersion solution to realize a high-solids-content(>77 wt%)slurry for high-mass-loading electrodes and to mitigate the migration of binder and conductive additives.Indeed,the approach reduces solvent usage by approximately 30%and ensures uniform conductive additive-binder domain distribution during electrode manufacturing,resulting in improved coating quality and adhesive strength for high-mass-loading electrodes(>12 mAh cm^(−2)).In terms of various electrode properties,the presented electrode showed low resistance and excellent electrochemical properties despite the low CNT contents of 0.6 wt%compared to the pristine-applied electrode with 0.85 wt%CNT contents.Moreover,our strategy enables faster drying,which increases the coating speed,thereby offering potential energy savings and supporting carbon neutrality in wet-based electrode manufacturing processes.
