In this paper,we establish and study a single-species logistic model with impulsive age-selective harvesting.First,we prove the ultimate boundedness of the solutions of the system.Then,we obtain conditions for the asy...In this paper,we establish and study a single-species logistic model with impulsive age-selective harvesting.First,we prove the ultimate boundedness of the solutions of the system.Then,we obtain conditions for the asymptotic stability of the trivial solution and the positive periodic solution.Finally,numerical simulations are presented to validate our results.Our results show that age-selective harvesting is more conducive to sustainable population survival than non-age-selective harvesting.展开更多
Predator–prey interactions are fundamental to understanding ecosystem stability and biodiversity.In this study,we propose and analyze a stochastic predator–prey model that incorporates two critical ecological factor...Predator–prey interactions are fundamental to understanding ecosystem stability and biodiversity.In this study,we propose and analyze a stochastic predator–prey model that incorporates two critical ecological factors:prey refuge and harvesting.The model also integrates disease transmission within the predator population,adding an important layer of realism.Using rigorous mathematical techniques,we demonstrate the existence and uniqueness of a global positive solution,thereby confirming the model's biological feasibility.We further derive sufficient conditions for two key ecological scenarios:stochastic permanence,which ensures the sustained co-existence of prey and predators over time,and extinction,where one or both populations decline to zero.The interplay between prey refuge and harvesting is thoroughly examined to understand their combined impact on population dynamics.All theoretical results are validated by detailed numerical simulations,highlighting the applicability of the model to real-world ecological systems.From the simulation results,we observed that with an adequate level of prey refuge and predator harvesting,the susceptible predator and prey coexist with extensive oscillations,while the infected predator population was moving towards extinction.In addition,we have investigated the effect of disease transmission on system dynamics.Our results show that,as the transmission rate of disease increases,the susceptible predator approaches extinction,whereas,on the other hand,when it declines,the susceptible predator shows robust oscillations while the infected approaches extinction.In both cases,the prey population demonstrates robust stability due to the prey refuge.Our findings show that the management of harvesting and the prey refuge can be effective ecological tactics for disease control and species protection under stochastic environmental effects.展开更多
Plants constitute nearly 80%of the planet’s total biomass(Bar-On et al.,2018);however,this vital group is experiencing severe threats,and recent evaluations indicate that approximately 45%of the world's described...Plants constitute nearly 80%of the planet’s total biomass(Bar-On et al.,2018);however,this vital group is experiencing severe threats,and recent evaluations indicate that approximately 45%of the world's described plant species are at risk of extinction(Bachman et al.,2024).The number of plant extinctions has increased by 60%in the last 100 years(Di Marco et al.,2017).Over the past 250 years,571 plant species have gone extinct—more than twice the combined total of extinct birds,mammals,and amphibians(217 species)(Briggs,2019).展开更多
BACKGROUND Fear-related disorders,such as post-traumatic stress disorder(PTSD),significantly impact patients and families.Exposure therapy is a common treatment,but imp-roving its effectiveness remains a key challenge...BACKGROUND Fear-related disorders,such as post-traumatic stress disorder(PTSD),significantly impact patients and families.Exposure therapy is a common treatment,but imp-roving its effectiveness remains a key challenge.Fear conditioning and extinction in animal models offer insights into its mechanisms.Our previous research indi-cates that DNA methyltransferases play a role in fear memory renewal.AIM To investigate the role of DNA methylation in the extinction of fear memory,with the goal of identifying potential strategies to enhance the efficacy of exposure therapy for fear-related disorders.METHODS This study investigated the role of DNA methylation in fear memory extinction in mice.DNA methylation was manipulated using N-phthalyl-L-tryptophan(RG108)to reduce methylation and L-methionine injections to enhance it.Neuronal activity,and dendritic spine density was measured following extinction training.RESULTS RG108 suppressed extinction,reduced spine density,and inhibited neuronal activity.Methionine injections facilitated extinction.CONCLUSION DNA methylation is crucial for fear memory extinction.Enhancing methylation may improve the efficacy of exposure therapy,offering a potential strategy to treat fear-related disorders.展开更多
Assessing the threat status of species in response to global change is critical for biodiversity monitoring and conservation efforts.However,current frameworks,even the IUCN Red List,often neglect critical factors suc...Assessing the threat status of species in response to global change is critical for biodiversity monitoring and conservation efforts.However,current frameworks,even the IUCN Red List,often neglect critical factors such as genetic diversity and the impacts of climate and land-use changes,hindering effective conservation planning.To address these limitations,we developed an enhanced extinction risk assessment framework using Diploderma lizards as a model.This framework incorporates long-term field surveys,environmental data,and land-use information to predict distributional changes for 10 recently described Diploderma species on the Qinghai-Xizang Plateau,which hold ecological significance but remain underassessed in conservation assessment.By integrating the distribution data and genetically inferred effective population sizes(Ne),we conducted scenario analyses and used a rank-sum approach to calculate Risk ranking scores(RRS)for each species.This approach revealed significant discrepancies with the IUCN Red List assessments.Notably,D.yangi and D.qilin were identified as facing the highest extinction risk.Furthermore,D.vela,D.batangense,D.flaviceps,D.dymondi,D.yulongense,and D.laeviventre,currently classified as“Least Concern”,were found to warrant reclassification as“Vulnerable”due to considerable threat from projected range contractions.Exploring the relationship between morphology and RRS revealed that traits such as snout-vent length and relative tail length could serve as potential predictors of extinction risk,offering preliminary metrics for assessing species vulnerability when comprehensive data are unavailable.This study enhances the precision of extinction risk assessment frameworks and demonstrates their capacity to refine and update risk assessments,especially for lesser-known taxa.展开更多
A stochastic epidemic model with two age groups is established in this study,in which the susceptible(S),the exposed(E),the infected(I),the hospitalized(H)and the recovered(R)are involved within the total population,t...A stochastic epidemic model with two age groups is established in this study,in which the susceptible(S),the exposed(E),the infected(I),the hospitalized(H)and the recovered(R)are involved within the total population,the aging rates between two age groups are set to be constant.The existence-and-uniqueness of global positive solution is firstly showed.Then,by constructing several appropriate Lyapunov functions and using the high-dimensional Itô’s formula,the sufficient conditions for the stochastic extinction and stochastic persistence of the exposed individuals and the infected individuals are obtained.The stochastic extinction indicator and the stochastic persistence indicator are less-valued expressions compared with the basic reproduction number.Meanwhile,the main results of this study are modified into multi-age groups.Furthermore,by using the surveillance data for Fujian Provincial Center for Disease Control and Prevention,Fuzhou COVID-19 epidemic is chosen to carry out the numerical simulations,which show that the age group of the population plays the vital role when studying infectious diseases.展开更多
The article studies the evolutionary dynamics of two-population two-strategy game models with and without impulses. First, the payment matrix is given and two evolutionary dynamics models are established by adding sto...The article studies the evolutionary dynamics of two-population two-strategy game models with and without impulses. First, the payment matrix is given and two evolutionary dynamics models are established by adding stochastic and impulse. For the stochastic model without impulses, the existence and uniqueness of solution, and the existence of positive periodic solutions are proved, and a sufficient condition for strategy extinction is given. For the stochastic model with impulses, the existence of positive periodic solutions is proved. Numerical results show that noise and impulses directly affect the model, but the periodicity of the model does not change.展开更多
The polarization properties of light are widely applied in imaging,communications,materials analy⁃sis,and life sciences.Various methods have been developed that can measure the polarization information of a target.How...The polarization properties of light are widely applied in imaging,communications,materials analy⁃sis,and life sciences.Various methods have been developed that can measure the polarization information of a target.However,conventional polarization detection systems are often bulky and complex,limiting their poten⁃tial for broader applications.To address the challenges of miniaturization,integrated polarization detectors have been extensively explored in recent years,achieving significant advancements in performance and functionality.In this review,we focus mainly on integrated polarization detectors with innovative features,including infinitely high polarization discrimination,ultrahigh sensitivity to polarization state change,full Stokes parameters measure⁃ment,and simultaneous perception of polarization and other key properties of light.Lastly,we discuss the oppor⁃tunities and challenges for the future development of integrated polarization photodetectors.展开更多
Nearly a quarter of animals living in rivers,lakes and other freshwater sources are threatened with extinction,according to new research published on Wednesday.“Huge rivers like the Amazon River can appear mighty,but...Nearly a quarter of animals living in rivers,lakes and other freshwater sources are threatened with extinction,according to new research published on Wednesday.“Huge rivers like the Amazon River can appear mighty,but at the same time,freshwater environments are very weak,”said the study's co⁃author Patricia Charvet,a biologist at Brazil's Federal University of Ceará.展开更多
Gastropods,as one of the most common invertebrates in shallow marine environments,were heavily impacted by the Permian–Triassic mass extinction(PTME),with severe loss of diversity and remarkable dwarfism of body size...Gastropods,as one of the most common invertebrates in shallow marine environments,were heavily impacted by the Permian–Triassic mass extinction(PTME),with severe loss of diversity and remarkable dwarfism of body size.Here,we report a new gastropod fauna from the Permian-Triassic carbonates of Zuodeng,Guangxi Province,South China.Five species belonging to five genera and two indeterminate taxa are identified.The Zuodeng fauna is dominated by Paleozoic holdover taxa,including Holopea teres,Protostylus sp.,and Wannerispira shangganensis although most of them are found in the basal Triassic microbialites.Three gastropod communities have been recognized by cluster analysis.Further morphological analyses show that the changing pattern of disparity,with diversity decreasing from communityⅡtoⅢ,fits the interior-reduction model.In addition,the morphospace of community in microbialites is higher than those in non-microbialite bearing beds at Zuodeng,shedding new light on the ecological role of microbialites during the Permian–Triassic environmental stress.展开更多
Persistent and maladaptive drug-related memories represent a key component in drug addiction.Converging evidence from both preclinical and clinical studies has demonstrated the potential efficacy of the memory reconso...Persistent and maladaptive drug-related memories represent a key component in drug addiction.Converging evidence from both preclinical and clinical studies has demonstrated the potential efficacy of the memory reconsolidation updating procedure(MRUP),a non-pharmacological strategy intertwining two distinct memory processes:reconsolidation and extinction—alternatively termed“the memory retrieval-extinction procedure”.This procedure presents a promising approach to attenuate,if not erase,entrenched drug memories and prevent relapse.The present review delineates the applications,molecular underpinnings,and operational boundaries of MRUP in the context of various forms of substance dependence.Furthermore,we critically examine the methodological limitations of MRUP,postulating potential refinement to optimize its therapeutic efficacy.In addition,we also look at the potential integration of MRUP and neurostimulation treatments in the domain of substance addiction.Overall,existing studies underscore the significant potential of MRUP,suggesting that interventions predicated on it could herald a promising avenue to enhance clinical outcomes in substance addiction therapy.展开更多
In this paper,a stochastic framework with a general nonmonotonic response function is formulated to investigate the competition dynamics between two species in a chemostat environment.The model incorporates both white...In this paper,a stochastic framework with a general nonmonotonic response function is formulated to investigate the competition dynamics between two species in a chemostat environment.The model incorporates both white noise and telegraph noise,the latter being described by Markov process.The existence of a unique global positive solution for the stochastic chemostat model is established.Subsequently,by using the ergodic theory of Markov process and utilizing techniques of stochastic analysis,the critical value differentiating between persistence in mean and extinction for the microorganism species is explored.Moreover,the existence of a unique stationary distribution is proved by using stochastic Lyapunov analysis.Finally,numerical simulations are introduced to support the obtained results.展开更多
Although hunting in the north-eastern Atlantic forest of Brazil began more than 500 years ago, no study to date has evaluated its impacts on the region’s mammalian fauna. For one year we carried out diurnal and noctu...Although hunting in the north-eastern Atlantic forest of Brazil began more than 500 years ago, no study to date has evaluated its impacts on the region’s mammalian fauna. For one year we carried out diurnal and nocturnal surveys using the Line Transect method in seven forest fragments varying from 7.32 ha to 469.76 ha, within a 4000 ha forest island archipelago, in Pernambuco State, Atlantic forest of northeastern Brazil. We calculated species density, population size, biomass and synergetic biomass, and recorded direct and indirect human impacts along the study transects. We recorded 44 mammalian species, of which 45.5% (n = 20) went extinct through hunting. The smallest forest fragment had the lowest richness, diversity, population size, and total biomass. It also had no synergetic biomass. The largest fragment had the highest richness, total density, and population size. There was a statistically significant relationship between fragment area and number of gunshots heard and suspended hunting platforms found;between population size and gunshots heard, suspended hunting platforms, free-roaming and feral dogs, and between total density and free-roaming and feral dogs. After more than 500 years of colonization hunting is still devastating, with larger fragments being linked to more hunters. Higher mammal abundances attracted more free-roaming and feral dogs, which have adapted to hunt wildlife on their own. Unless we protect every single forest fragment and create sustainable landscapes, we will not be able to save this hotspot’s hotspot.展开更多
Post-traumatic stress disorder(PTSD)is a psychiatric disorder caused by traumatic past experiences,rooted in the neurocircuits of fear memory formation.Memory processes include encoding,storing,and recalling to forget...Post-traumatic stress disorder(PTSD)is a psychiatric disorder caused by traumatic past experiences,rooted in the neurocircuits of fear memory formation.Memory processes include encoding,storing,and recalling to forgetting,suggesting the potential to erase fear memories through timely interventions.Conventional strategies such as medications or electroconvulsive therapy often fail to provide permanent relief and come with significant side-effects.This review explores how fear memory may be erased,particularly focusing on the mnemonic phases of reconsolidation and extinction.Reconsolidation strengthens memory,while extinction weakens it.Interfering with memory reconsolidation could diminish the fear response.Alternatively,the extinction of acquired memory could reduce the fear memory response.This review summarizes experimental animal models of PTSD,examines the nature and epidemiology of reconsolidation to extinction,and discusses current behavioral therapy aimed at transforming fear memories to treat PTSD.In sum,understanding how fear memory updates holds significant promise for PTSD treatment.展开更多
The End-Permian mass extinction(EPME),Earth’s most severe biocrisis,occurred proximal to the Permian-Triassic Boundary(PTB),with marine ecosystems experiencing catastrophic collapse.This study employs stable carbon(...The End-Permian mass extinction(EPME),Earth’s most severe biocrisis,occurred proximal to the Permian-Triassic Boundary(PTB),with marine ecosystems experiencing catastrophic collapse.This study employs stable carbon(δ^(13)C)and oxygen isotopes from marine carbonates in the Haidai Section(Xuanwei,northeastern Yunnan)to decipher paleoenvironmental drivers.The well-preserved stratigraphic sequence encompasses the Upper Permian(Yangxin and Xuanwei Formations)transitioning into the Lower Triassic(Feixianguan and Jialingjiang Formations),providing a continuous marine sedimentary archive.A marked negativeδ^(13)C excursion(-9.66‰V-PDB)occurs at the PTB,initiating from+0.82‰with subsequent gradual recovery.This geochemical signature correlates with:90%reduction in primary productivity Biodiversity collapse exhibiting cluster extinction patterns Prolonged suppression of ecological recovery Concurrently,reconstructed seawater temperatures reveal extreme thermal fluctuations,surging from 23℃to 32℃at the PTB before precipitously declining to 16℃.These perturbations demonstrate coupled biogeochemical dynamics wherein:•Carbon cycle destabilization disrupted nutrient fluxes.•Temperature oscillations exceeded marine taxa thermal tolerances.•Synergistic environmental stresses amplified extinction selectivity.Theδ^(13)C-temperature covariance(r^(2)=0.085)establishes mechanistic linkages between physicochemical perturbations and biotic responses.Our findings demonstrate that the EPME was driven by positive feedback loops in which:Volcanic CO₂emissions triggered carbonate saturation decline Thermal stratification exacerbated anoxia Biogeochemical cycling perturbations suppressed primary producers This integrated geochemical record from the Haidai Section provides critical insights into environment-organism coevolution during Phanerozoic Earth’s most profound mass extinction.展开更多
Nestedness is one of the important patterns in island biogeography,community ecology and conservation biology.However,most previous nestedness studies focus on the taxonomic dimension while neglecting the functional a...Nestedness is one of the important patterns in island biogeography,community ecology and conservation biology.However,most previous nestedness studies focus on the taxonomic dimension while neglecting the functional and phylogenetic processes in generating nestedness.Moreover,few studies have examined the seasonal change of the nestedness and underlying processes.Here,we examined the seasonal nestedness of bird assemblages in taxonomic,functional,and phylogenetic dimensions,and determined the underlying processes of nestedness patterns in the Zhoushan Archipelago,China.We surveyed the occurrence, abundance,and habitats of birds on 40 islands.We calculated taxonomic,functional,and phylogenetic nestedness using WNODF and treeNODF.We determined the processes underlying nestedness by relating nestedness ranks to island characteristics and species traits.The WNODF analyses showed that bird assemblages in winter and summer were both significantly nested.The habitat-by-site matrix was also significantly nested.The nestedness of bird assemblages was significantly correlated with island area,habitat diversity,habitat specificity,minimum area requirement,habitat specificity and hand-wing index(HWI) of birds in both seasons.While the distance to the nearest mainland(DTM) exerted the influence on nestedness in summer,the distance to the nearest larger island(DTNL)affected nestedness only in winter.However,the nestedness of bird assemblages was not caused by passive sampling or human disturbance.The results of treeNODF analyses illustrated that bird assemblages were functionally and phylogenetically nested in summer and winter,but the exact mechanisms were somewhat different in these two seasons.Overall,our results supported the habitat nestedness hypothesis,selective extinction hypothesis,and selective colonization hypothesis in both seasons.From a conservation viewpoint,we should protect islands with large area and diverse habitats,islands close to the mainland,and species with large area requirement and high habitat specificity to prevent local extinction.展开更多
Based on the work of Mumby et al.[Thresholds and the resilience of Caribbean coral reefs,Nature 450(2007)98-101],this study is devoted to investigate the deterministic and stochastic features of a coral reef ecosystem...Based on the work of Mumby et al.[Thresholds and the resilience of Caribbean coral reefs,Nature 450(2007)98-101],this study is devoted to investigate the deterministic and stochastic features of a coral reef ecosystem in which macroalgae and coral compete to occupy algae turfs,and the macroalgae are grazed by parrotfish.By taking the grazing rate as the focused parameter,we completely analyze the global dynamics of the deterministic coral reef ecosystem,including bistable phenomenon,linear equilibria and degenerate attractor.It is found that for different grazing rates,the coral reef system may exhibit rich dynamics which are closely dependent on the initial values.Furthermore,we derive a stochastic coral reef model in the form of continuous-time Markov chain(CTMC),and estimate the extinction probabilities of macroalgae and coral by using the branching process theory.Analytical results reveal that the macroalgae or coral species will go to extinction in a positive probability,even if it can survive in the deterministic environment.展开更多
This research directly supported the author’s thesis work in partial fulfilment of Master of Science in biology from the University of North Texas(United States)from August 1996 to September 1997.Two sites at Lake Ra...This research directly supported the author’s thesis work in partial fulfilment of Master of Science in biology from the University of North Texas(United States)from August 1996 to September 1997.Two sites at Lake Ray Roberts,Denton County,Texas(United States)were examined and contrasted for productivity.The site located in the pelagic zone exhibited a slight,thermal gradient with no stratification,and a slightly stratified clinograde oxygen profile which is typical for summer-stratified eutrophic lakes.The site located in the shallow,littoral zone exhibited high,increasing turbidity with depth,marked by shallow light attenuation through the water column.Temperature was constant at every depth in the littoral site,with a slight,clinograde oxygen profile,typical for shallow,littoral areas subject to wind-induced mixing.Volume estimations of chlorophyll-α shows a strong presence in the euphotic zone,indicating photosynthesis occurs until approximately 2.2 m below the surface.The shallow,littoral site showed the basic signs of higher productivity than the open,pelagic site.展开更多
In the contemporary research landscape of mental illness treatment,fear-related disorders such as post-traumatic stress disorder continue to pose significant challenges.Although exposure therapy remains a fundamental ...In the contemporary research landscape of mental illness treatment,fear-related disorders such as post-traumatic stress disorder continue to pose significant challenges.Although exposure therapy remains a fundamental component of treatment,its efficacy varies considerably among individuals.DNA methylation plays a pivotal role in the extinction of fear memories,providing a promising molecular mechanism that could enhance the success of exposure-based interventions.Extensive studies have consistently demonstrated a substantial association between DNA methylation and neuronal plasticity.While DNA methylation holds potential regulatory effects on the effectiveness of exposure therapy,the bidirectional regulatory relationship between it and neuronal activity necessitates addressing several challenges before its widespread clinical application for mental disorders.First,excessive DNA methylation may suppress neural function,and non-selective enhancement of methylation could be counterproductive.Furthermore,due to potential systemic side effects,the use of methylation-modulating agents might disrupt the physiological balance and functionality of other organs and systems.Despite the dynamic interplay between DNA methylation and neuronal activity offering novel insights into the treatment of mental disorders, the strict consideration of target specificity and an appropriate dosing window requirescautious implementation in clinical practice.展开更多
This study examines diffuse ultraviolet(UV)emissions in the PHOENIX_00 region near galaxy clusters using GALEX deep observations.In the far-UV(FUV)and near-UV(NUV),we detected backgrounds of 125-200 and225-350 photon ...This study examines diffuse ultraviolet(UV)emissions in the PHOENIX_00 region near galaxy clusters using GALEX deep observations.In the far-UV(FUV)and near-UV(NUV),we detected backgrounds of 125-200 and225-350 photon units(PU),with scatters of±16 and±22 PU,respectively.A moderate FUV-NUV correlation and FUV/NUV ratio below unity indicate FUV-dominated emission and little molecular hydrogen fluorescence or hot-line contributions.Dust influences the FUV background more strongly than the NUV,and UV band emissions correlate more strongly at Galactic latitudes|gb|>71°.29.Infrared(IR)color ratios IR_(60)/IR_(100)(≈0.34±0.03)indicate homogeneous large-grain temperatures and depletion of small grains and PAHs,while IR60/IR25 below 3 indicates AGN activity in the region.The non-zero offsets of IR-UV plots 89 PU(FUV)and199 PU(NUV)indicate the region s baseline illumination and extragalactic radiation.Approximately 11%of the FUV offset and 23%of the NUV offset come from extragalactic background light,while the rest comes from dust-scattered starlight.Finally,our research shows that the interstellar radiation field directly affects the UV background,with the strength inversely proportional to local dust content.展开更多
基金Supported by the National Natural Science Foundation of China(12261018)Universities Key Laboratory of Mathematical Modeling and Data Mining in Guizhou Province(2023013)。
文摘In this paper,we establish and study a single-species logistic model with impulsive age-selective harvesting.First,we prove the ultimate boundedness of the solutions of the system.Then,we obtain conditions for the asymptotic stability of the trivial solution and the positive periodic solution.Finally,numerical simulations are presented to validate our results.Our results show that age-selective harvesting is more conducive to sustainable population survival than non-age-selective harvesting.
基金supported by the National Natural Science Foundation of China(Grant No.32271554)the Guangdong Basic and Applied Basic Research Foundation(Grant No.2023A1515011501)。
文摘Predator–prey interactions are fundamental to understanding ecosystem stability and biodiversity.In this study,we propose and analyze a stochastic predator–prey model that incorporates two critical ecological factors:prey refuge and harvesting.The model also integrates disease transmission within the predator population,adding an important layer of realism.Using rigorous mathematical techniques,we demonstrate the existence and uniqueness of a global positive solution,thereby confirming the model's biological feasibility.We further derive sufficient conditions for two key ecological scenarios:stochastic permanence,which ensures the sustained co-existence of prey and predators over time,and extinction,where one or both populations decline to zero.The interplay between prey refuge and harvesting is thoroughly examined to understand their combined impact on population dynamics.All theoretical results are validated by detailed numerical simulations,highlighting the applicability of the model to real-world ecological systems.From the simulation results,we observed that with an adequate level of prey refuge and predator harvesting,the susceptible predator and prey coexist with extensive oscillations,while the infected predator population was moving towards extinction.In addition,we have investigated the effect of disease transmission on system dynamics.Our results show that,as the transmission rate of disease increases,the susceptible predator approaches extinction,whereas,on the other hand,when it declines,the susceptible predator shows robust oscillations while the infected approaches extinction.In both cases,the prey population demonstrates robust stability due to the prey refuge.Our findings show that the management of harvesting and the prey refuge can be effective ecological tactics for disease control and species protection under stochastic environmental effects.
基金support of the ORG.one project of Oxford Nanopore Technologies(ONT),the Rufford Grants(45249-1)the Idea Wild Grants(Project ID-KJOSINDI0125-00)the Mohamed Bin Zyed Species Conservation(MBZ)(GEF Grant no-240535253)Funds in our efforts to conserve threatened trees in the Western Ghats Biodiversity Hotspot Forest regions.
文摘Plants constitute nearly 80%of the planet’s total biomass(Bar-On et al.,2018);however,this vital group is experiencing severe threats,and recent evaluations indicate that approximately 45%of the world's described plant species are at risk of extinction(Bachman et al.,2024).The number of plant extinctions has increased by 60%in the last 100 years(Di Marco et al.,2017).Over the past 250 years,571 plant species have gone extinct—more than twice the combined total of extinct birds,mammals,and amphibians(217 species)(Briggs,2019).
基金Supported by National Natural Science Foundation of China,No.82360231Yunnan Basic Research Program General Project,No.202401AT070075+1 种基金Dali Basic Research Program Key Project,No.202301A020021Youth Special Project for Basic Research of Local Universities in Yunnan Province,No.202301BA070001-127.
文摘BACKGROUND Fear-related disorders,such as post-traumatic stress disorder(PTSD),significantly impact patients and families.Exposure therapy is a common treatment,but imp-roving its effectiveness remains a key challenge.Fear conditioning and extinction in animal models offer insights into its mechanisms.Our previous research indi-cates that DNA methyltransferases play a role in fear memory renewal.AIM To investigate the role of DNA methylation in the extinction of fear memory,with the goal of identifying potential strategies to enhance the efficacy of exposure therapy for fear-related disorders.METHODS This study investigated the role of DNA methylation in fear memory extinction in mice.DNA methylation was manipulated using N-phthalyl-L-tryptophan(RG108)to reduce methylation and L-methionine injections to enhance it.Neuronal activity,and dendritic spine density was measured following extinction training.RESULTS RG108 suppressed extinction,reduced spine density,and inhibited neuronal activity.Methionine injections facilitated extinction.CONCLUSION DNA methylation is crucial for fear memory extinction.Enhancing methylation may improve the efficacy of exposure therapy,offering a potential strategy to treat fear-related disorders.
基金supported by the Second Tibetan Plateau Scientific Expedition and Research Program (STEP,2019QZKK0402)Science and Technology Plan Project of Xizang Autonomous Region to Y.Q. (XZ202201ZY0030G)National Natural Science Foundation of China (32201424 to Z.Y.L.and 31872233 to Y.Q.)。
文摘Assessing the threat status of species in response to global change is critical for biodiversity monitoring and conservation efforts.However,current frameworks,even the IUCN Red List,often neglect critical factors such as genetic diversity and the impacts of climate and land-use changes,hindering effective conservation planning.To address these limitations,we developed an enhanced extinction risk assessment framework using Diploderma lizards as a model.This framework incorporates long-term field surveys,environmental data,and land-use information to predict distributional changes for 10 recently described Diploderma species on the Qinghai-Xizang Plateau,which hold ecological significance but remain underassessed in conservation assessment.By integrating the distribution data and genetically inferred effective population sizes(Ne),we conducted scenario analyses and used a rank-sum approach to calculate Risk ranking scores(RRS)for each species.This approach revealed significant discrepancies with the IUCN Red List assessments.Notably,D.yangi and D.qilin were identified as facing the highest extinction risk.Furthermore,D.vela,D.batangense,D.flaviceps,D.dymondi,D.yulongense,and D.laeviventre,currently classified as“Least Concern”,were found to warrant reclassification as“Vulnerable”due to considerable threat from projected range contractions.Exploring the relationship between morphology and RRS revealed that traits such as snout-vent length and relative tail length could serve as potential predictors of extinction risk,offering preliminary metrics for assessing species vulnerability when comprehensive data are unavailable.This study enhances the precision of extinction risk assessment frameworks and demonstrates their capacity to refine and update risk assessments,especially for lesser-known taxa.
基金Supported by National Natural Science Foundation of China(61911530398,12231012)Consultancy Project by the Chinese Academy of Engineering(2022-JB-06,2023-JB-12)+3 种基金the Natural Science Foundation of Fujian Province of China(2021J01621)Special Projects of the Central Government Guiding Local Science and Technology Development(2021L3018)Royal Society of Edinburgh(RSE1832)Engineering and Physical Sciences Research Council(EP/W522521/1).
文摘A stochastic epidemic model with two age groups is established in this study,in which the susceptible(S),the exposed(E),the infected(I),the hospitalized(H)and the recovered(R)are involved within the total population,the aging rates between two age groups are set to be constant.The existence-and-uniqueness of global positive solution is firstly showed.Then,by constructing several appropriate Lyapunov functions and using the high-dimensional Itô’s formula,the sufficient conditions for the stochastic extinction and stochastic persistence of the exposed individuals and the infected individuals are obtained.The stochastic extinction indicator and the stochastic persistence indicator are less-valued expressions compared with the basic reproduction number.Meanwhile,the main results of this study are modified into multi-age groups.Furthermore,by using the surveillance data for Fujian Provincial Center for Disease Control and Prevention,Fuzhou COVID-19 epidemic is chosen to carry out the numerical simulations,which show that the age group of the population plays the vital role when studying infectious diseases.
基金Supported by the National Natural Science Foundation of China(10671182)。
文摘The article studies the evolutionary dynamics of two-population two-strategy game models with and without impulses. First, the payment matrix is given and two evolutionary dynamics models are established by adding stochastic and impulse. For the stochastic model without impulses, the existence and uniqueness of solution, and the existence of positive periodic solutions are proved, and a sufficient condition for strategy extinction is given. For the stochastic model with impulses, the existence of positive periodic solutions is proved. Numerical results show that noise and impulses directly affect the model, but the periodicity of the model does not change.
基金Supported by the National Key Research and Development Program of China(2022YFA1404602)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB0580000)+3 种基金the National Natural Science Foundation of China(U23B2045,62305362)the Program of Shanghai Academic/Technology Research Leader(22XD1424400)the Fund of SITP Innovation Foundation(CX-461 and CX-522)Special Project to Seize the Commanding Heights of Science and Technology of Chinese Academy of Sciences,subtopic(GJ0090406-6).
文摘The polarization properties of light are widely applied in imaging,communications,materials analy⁃sis,and life sciences.Various methods have been developed that can measure the polarization information of a target.However,conventional polarization detection systems are often bulky and complex,limiting their poten⁃tial for broader applications.To address the challenges of miniaturization,integrated polarization detectors have been extensively explored in recent years,achieving significant advancements in performance and functionality.In this review,we focus mainly on integrated polarization detectors with innovative features,including infinitely high polarization discrimination,ultrahigh sensitivity to polarization state change,full Stokes parameters measure⁃ment,and simultaneous perception of polarization and other key properties of light.Lastly,we discuss the oppor⁃tunities and challenges for the future development of integrated polarization photodetectors.
文摘Nearly a quarter of animals living in rivers,lakes and other freshwater sources are threatened with extinction,according to new research published on Wednesday.“Huge rivers like the Amazon River can appear mighty,but at the same time,freshwater environments are very weak,”said the study's co⁃author Patricia Charvet,a biologist at Brazil's Federal University of Ceará.
基金supported by the National Natural Science Foundation of China(Nos.41730320,42030513)。
文摘Gastropods,as one of the most common invertebrates in shallow marine environments,were heavily impacted by the Permian–Triassic mass extinction(PTME),with severe loss of diversity and remarkable dwarfism of body size.Here,we report a new gastropod fauna from the Permian-Triassic carbonates of Zuodeng,Guangxi Province,South China.Five species belonging to five genera and two indeterminate taxa are identified.The Zuodeng fauna is dominated by Paleozoic holdover taxa,including Holopea teres,Protostylus sp.,and Wannerispira shangganensis although most of them are found in the basal Triassic microbialites.Three gastropod communities have been recognized by cluster analysis.Further morphological analyses show that the changing pattern of disparity,with diversity decreasing from communityⅡtoⅢ,fits the interior-reduction model.In addition,the morphospace of community in microbialites is higher than those in non-microbialite bearing beds at Zuodeng,shedding new light on the ecological role of microbialites during the Permian–Triassic environmental stress.
基金supported by the National Natural Science Foundation of China(82071498,81871046,and 32161143022)STI2030-Major Projects(2022ZD0214500).
文摘Persistent and maladaptive drug-related memories represent a key component in drug addiction.Converging evidence from both preclinical and clinical studies has demonstrated the potential efficacy of the memory reconsolidation updating procedure(MRUP),a non-pharmacological strategy intertwining two distinct memory processes:reconsolidation and extinction—alternatively termed“the memory retrieval-extinction procedure”.This procedure presents a promising approach to attenuate,if not erase,entrenched drug memories and prevent relapse.The present review delineates the applications,molecular underpinnings,and operational boundaries of MRUP in the context of various forms of substance dependence.Furthermore,we critically examine the methodological limitations of MRUP,postulating potential refinement to optimize its therapeutic efficacy.In addition,we also look at the potential integration of MRUP and neurostimulation treatments in the domain of substance addiction.Overall,existing studies underscore the significant potential of MRUP,suggesting that interventions predicated on it could herald a promising avenue to enhance clinical outcomes in substance addiction therapy.
基金supported by the Natural Science Foundation of Jiangsu Province,P.R.China(No.BK20220553)the China Postdoctoral Science Foundation(No.2023M742955)Z.Qiu's work was supported by the National Natural Science Foundation of China(No.12071217).
文摘In this paper,a stochastic framework with a general nonmonotonic response function is formulated to investigate the competition dynamics between two species in a chemostat environment.The model incorporates both white noise and telegraph noise,the latter being described by Markov process.The existence of a unique global positive solution for the stochastic chemostat model is established.Subsequently,by using the ergodic theory of Markov process and utilizing techniques of stochastic analysis,the critical value differentiating between persistence in mean and extinction for the microorganism species is explored.Moreover,the existence of a unique stationary distribution is proved by using stochastic Lyapunov analysis.Finally,numerical simulations are introduced to support the obtained results.
文摘Although hunting in the north-eastern Atlantic forest of Brazil began more than 500 years ago, no study to date has evaluated its impacts on the region’s mammalian fauna. For one year we carried out diurnal and nocturnal surveys using the Line Transect method in seven forest fragments varying from 7.32 ha to 469.76 ha, within a 4000 ha forest island archipelago, in Pernambuco State, Atlantic forest of northeastern Brazil. We calculated species density, population size, biomass and synergetic biomass, and recorded direct and indirect human impacts along the study transects. We recorded 44 mammalian species, of which 45.5% (n = 20) went extinct through hunting. The smallest forest fragment had the lowest richness, diversity, population size, and total biomass. It also had no synergetic biomass. The largest fragment had the highest richness, total density, and population size. There was a statistically significant relationship between fragment area and number of gunshots heard and suspended hunting platforms found;between population size and gunshots heard, suspended hunting platforms, free-roaming and feral dogs, and between total density and free-roaming and feral dogs. After more than 500 years of colonization hunting is still devastating, with larger fragments being linked to more hunters. Higher mammal abundances attracted more free-roaming and feral dogs, which have adapted to hunt wildlife on their own. Unless we protect every single forest fragment and create sustainable landscapes, we will not be able to save this hotspot’s hotspot.
基金supported by the National Key Research and Development Project of China(2021ZD0202800)the National Natural Science Foundation of China(U21A20418,82003727).
文摘Post-traumatic stress disorder(PTSD)is a psychiatric disorder caused by traumatic past experiences,rooted in the neurocircuits of fear memory formation.Memory processes include encoding,storing,and recalling to forgetting,suggesting the potential to erase fear memories through timely interventions.Conventional strategies such as medications or electroconvulsive therapy often fail to provide permanent relief and come with significant side-effects.This review explores how fear memory may be erased,particularly focusing on the mnemonic phases of reconsolidation and extinction.Reconsolidation strengthens memory,while extinction weakens it.Interfering with memory reconsolidation could diminish the fear response.Alternatively,the extinction of acquired memory could reduce the fear memory response.This review summarizes experimental animal models of PTSD,examines the nature and epidemiology of reconsolidation to extinction,and discusses current behavioral therapy aimed at transforming fear memories to treat PTSD.In sum,understanding how fear memory updates holds significant promise for PTSD treatment.
基金supported by the Scientific Research Fund of the Education Department of Yunnan Province(Grant Number:2019J0488).
文摘The End-Permian mass extinction(EPME),Earth’s most severe biocrisis,occurred proximal to the Permian-Triassic Boundary(PTB),with marine ecosystems experiencing catastrophic collapse.This study employs stable carbon(δ^(13)C)and oxygen isotopes from marine carbonates in the Haidai Section(Xuanwei,northeastern Yunnan)to decipher paleoenvironmental drivers.The well-preserved stratigraphic sequence encompasses the Upper Permian(Yangxin and Xuanwei Formations)transitioning into the Lower Triassic(Feixianguan and Jialingjiang Formations),providing a continuous marine sedimentary archive.A marked negativeδ^(13)C excursion(-9.66‰V-PDB)occurs at the PTB,initiating from+0.82‰with subsequent gradual recovery.This geochemical signature correlates with:90%reduction in primary productivity Biodiversity collapse exhibiting cluster extinction patterns Prolonged suppression of ecological recovery Concurrently,reconstructed seawater temperatures reveal extreme thermal fluctuations,surging from 23℃to 32℃at the PTB before precipitously declining to 16℃.These perturbations demonstrate coupled biogeochemical dynamics wherein:•Carbon cycle destabilization disrupted nutrient fluxes.•Temperature oscillations exceeded marine taxa thermal tolerances.•Synergistic environmental stresses amplified extinction selectivity.Theδ^(13)C-temperature covariance(r^(2)=0.085)establishes mechanistic linkages between physicochemical perturbations and biotic responses.Our findings demonstrate that the EPME was driven by positive feedback loops in which:Volcanic CO₂emissions triggered carbonate saturation decline Thermal stratification exacerbated anoxia Biogeochemical cycling perturbations suppressed primary producers This integrated geochemical record from the Haidai Section provides critical insights into environment-organism coevolution during Phanerozoic Earth’s most profound mass extinction.
基金supported by the National Natural Science Foundation of China (32271734)。
文摘Nestedness is one of the important patterns in island biogeography,community ecology and conservation biology.However,most previous nestedness studies focus on the taxonomic dimension while neglecting the functional and phylogenetic processes in generating nestedness.Moreover,few studies have examined the seasonal change of the nestedness and underlying processes.Here,we examined the seasonal nestedness of bird assemblages in taxonomic,functional,and phylogenetic dimensions,and determined the underlying processes of nestedness patterns in the Zhoushan Archipelago,China.We surveyed the occurrence, abundance,and habitats of birds on 40 islands.We calculated taxonomic,functional,and phylogenetic nestedness using WNODF and treeNODF.We determined the processes underlying nestedness by relating nestedness ranks to island characteristics and species traits.The WNODF analyses showed that bird assemblages in winter and summer were both significantly nested.The habitat-by-site matrix was also significantly nested.The nestedness of bird assemblages was significantly correlated with island area,habitat diversity,habitat specificity,minimum area requirement,habitat specificity and hand-wing index(HWI) of birds in both seasons.While the distance to the nearest mainland(DTM) exerted the influence on nestedness in summer,the distance to the nearest larger island(DTNL)affected nestedness only in winter.However,the nestedness of bird assemblages was not caused by passive sampling or human disturbance.The results of treeNODF analyses illustrated that bird assemblages were functionally and phylogenetically nested in summer and winter,but the exact mechanisms were somewhat different in these two seasons.Overall,our results supported the habitat nestedness hypothesis,selective extinction hypothesis,and selective colonization hypothesis in both seasons.From a conservation viewpoint,we should protect islands with large area and diverse habitats,islands close to the mainland,and species with large area requirement and high habitat specificity to prevent local extinction.
基金supported by the grants from National Natural Science Foundation of China(12231012,12161005,62173161).
文摘Based on the work of Mumby et al.[Thresholds and the resilience of Caribbean coral reefs,Nature 450(2007)98-101],this study is devoted to investigate the deterministic and stochastic features of a coral reef ecosystem in which macroalgae and coral compete to occupy algae turfs,and the macroalgae are grazed by parrotfish.By taking the grazing rate as the focused parameter,we completely analyze the global dynamics of the deterministic coral reef ecosystem,including bistable phenomenon,linear equilibria and degenerate attractor.It is found that for different grazing rates,the coral reef system may exhibit rich dynamics which are closely dependent on the initial values.Furthermore,we derive a stochastic coral reef model in the form of continuous-time Markov chain(CTMC),and estimate the extinction probabilities of macroalgae and coral by using the branching process theory.Analytical results reveal that the macroalgae or coral species will go to extinction in a positive probability,even if it can survive in the deterministic environment.
文摘This research directly supported the author’s thesis work in partial fulfilment of Master of Science in biology from the University of North Texas(United States)from August 1996 to September 1997.Two sites at Lake Ray Roberts,Denton County,Texas(United States)were examined and contrasted for productivity.The site located in the pelagic zone exhibited a slight,thermal gradient with no stratification,and a slightly stratified clinograde oxygen profile which is typical for summer-stratified eutrophic lakes.The site located in the shallow,littoral zone exhibited high,increasing turbidity with depth,marked by shallow light attenuation through the water column.Temperature was constant at every depth in the littoral site,with a slight,clinograde oxygen profile,typical for shallow,littoral areas subject to wind-induced mixing.Volume estimations of chlorophyll-α shows a strong presence in the euphotic zone,indicating photosynthesis occurs until approximately 2.2 m below the surface.The shallow,littoral site showed the basic signs of higher productivity than the open,pelagic site.
基金Supported by the General Program of the Joint Fund Project Under the Liaoning Provincial Science and Technology Plan,No.2024-MSLH-104Research Project Plan of the Qingpu Branch of Zhongshan Hospital,No.QYT2023-02Research Topic of the Shanghai Qingpu District Health Commission,No.QWJ2024-10.
文摘In the contemporary research landscape of mental illness treatment,fear-related disorders such as post-traumatic stress disorder continue to pose significant challenges.Although exposure therapy remains a fundamental component of treatment,its efficacy varies considerably among individuals.DNA methylation plays a pivotal role in the extinction of fear memories,providing a promising molecular mechanism that could enhance the success of exposure-based interventions.Extensive studies have consistently demonstrated a substantial association between DNA methylation and neuronal plasticity.While DNA methylation holds potential regulatory effects on the effectiveness of exposure therapy,the bidirectional regulatory relationship between it and neuronal activity necessitates addressing several challenges before its widespread clinical application for mental disorders.First,excessive DNA methylation may suppress neural function,and non-selective enhancement of methylation could be counterproductive.Furthermore,due to potential systemic side effects,the use of methylation-modulating agents might disrupt the physiological balance and functionality of other organs and systems.Despite the dynamic interplay between DNA methylation and neuronal activity offering novel insights into the treatment of mental disorders, the strict consideration of target specificity and an appropriate dosing window requirescautious implementation in clinical practice.
文摘This study examines diffuse ultraviolet(UV)emissions in the PHOENIX_00 region near galaxy clusters using GALEX deep observations.In the far-UV(FUV)and near-UV(NUV),we detected backgrounds of 125-200 and225-350 photon units(PU),with scatters of±16 and±22 PU,respectively.A moderate FUV-NUV correlation and FUV/NUV ratio below unity indicate FUV-dominated emission and little molecular hydrogen fluorescence or hot-line contributions.Dust influences the FUV background more strongly than the NUV,and UV band emissions correlate more strongly at Galactic latitudes|gb|>71°.29.Infrared(IR)color ratios IR_(60)/IR_(100)(≈0.34±0.03)indicate homogeneous large-grain temperatures and depletion of small grains and PAHs,while IR60/IR25 below 3 indicates AGN activity in the region.The non-zero offsets of IR-UV plots 89 PU(FUV)and199 PU(NUV)indicate the region s baseline illumination and extragalactic radiation.Approximately 11%of the FUV offset and 23%of the NUV offset come from extragalactic background light,while the rest comes from dust-scattered starlight.Finally,our research shows that the interstellar radiation field directly affects the UV background,with the strength inversely proportional to local dust content.
