The population system is the only subsystem tha has charecteristic of subjectivity in theregional PRED system. Influenced by the particular status quo of natural resources and environmentconditions, the population sub...The population system is the only subsystem tha has charecteristic of subjectivity in theregional PRED system. Influenced by the particular status quo of natural resources and environmentconditions, the population subsystem of the Qaidam Basin is very different from those of otherregions'. Based on the on-the-spot investigation to the Qaidam Basin in July 1997, the authors of thispaper sum up several characters of the population subsystem of the Basin. (1) Population mainlyconsisting of the big volume of immigrants and floating population increases very fast. (2) With highpopulation mobility there was great discrepany between the actual number of population (aggregatepopulation) and the statidtical population. (3) Degree of urbanization is very high, and employmentconcentrates mainly on the industrial and teftiary industrial sectors. (4) Sex ratio remains veryunbalanced, especially in the youth group of population which exerts high pressure on employmentand training because of the young age structure. (5) Population quality is relatively high as a wholeWhile educahonal level characterizes the undeveloped regions. In order to predict the futurepopulation of the Basin. according to the characters of population system, this paper puts forward away called dividing-steps-forecast-sum to do the prediction till 2050, use both modeling forecastingmethod and empirical evaluation. The results indicated that the total population of the Basin whllreach 1 .28 million in 2050. Among them, the natural increment and immigrant and floating incrementoccupy 34.99% and 60.86%, respectively, with another 4.13% of special population. In terms ofcharactedstics of population and predicted results as well as the status quo of natural resources andenvironment this paper suggests several thoughts to optimize and adjust the population system of theQaidam Basin. They are, firsuy, to control the number of population as well as improve thepopulation quality, and secondly, to reghate the floating population to assort them withsocioeconomic development in the Basin. Above all, the most important step is to throw high level ofscience and techniqte into the Basin's socioeconomic system to enhance the carrying capacity ofresources and environment and improve the coordinated relationship among population, resources andcnvironment展开更多
In this paper,a population system with cross-diffusion and habitat complexity is selected as study object.We investigate that how cross-diffusion and habitat complexity destabilize the otherwise stable periodic soluti...In this paper,a population system with cross-diffusion and habitat complexity is selected as study object.We investigate that how cross-diffusion and habitat complexity destabilize the otherwise stable periodic solutions of the ODEs to generate the new abundant spatial Turing patterns.By utilizing the local Hopf bifurcation theorem and perturbation theory,we establish a formula to determine the Turing instability of periodic solutions of the population system withcross-diffusion and habitat complexity.Finally,numerical simulations are performed to verify theoretical analysis,simultaneously,we verify the formation process of spatial Turing patterns when the cross-diffusion coefficients and habitat complexity change.展开更多
In this paper,we consider the optimal boundary control problem of a two-species competitive system with time delay and size structure in a polluted environment.First,the well posedness of the system is studied by usin...In this paper,we consider the optimal boundary control problem of a two-species competitive system with time delay and size structure in a polluted environment.First,the well posedness of the system is studied by using the characteristic line method and the fixed point principle.Second,the necessary conditions for optimal boundary control are obtained by conjugate system and normal cone property.Finally,the existence and uniqueness of the optimal strategy are proved by Ekeland variational principle.展开更多
Objective:This study aims to estimate the thyroid cancer(TC)burden and trends from 1990 and 2021 among working-age population(WAP),at the global,regional,and national levels.Methods:Based on the Global Burden of Disea...Objective:This study aims to estimate the thyroid cancer(TC)burden and trends from 1990 and 2021 among working-age population(WAP),at the global,regional,and national levels.Methods:Based on the Global Burden of Disease 2021 study,this cross-sectional study included data on TC incidence and mortality for WAP aged 15-64 years across 204 countries and territories from 1990 to 2021.The age-standardized incidence rate(ASIR)and age-standardized mortality rate(ASMR)of TC were used to estimate the disease burden.Temporal trends of ASIR and ASMR were estimated by average annual percentage changes(AAPCs)based on age-period-cohort models.Relative inequality of TC burden across 204 countries was estimated by the slope index of concentration index.Results:Globally,ASIR of TC increased from 2.27 per 100,000 population to 3.41 per 100,000 population from1990 to 2021,with AAPC of 1.59%[95%confidence interval(95%CI):1.54,1.64];in contrast,ASMRs were stable at 0.31 per 100,000 population.Females had a higher disease burden than males,and adults aged 45-64 years accounted for more than 55%of the TC cases.Across regions and countries,North Africa and Comoros experienced the highest increase in ASIR,with AAPCs of 2.97%and 7.73%,respectively.All socio-demographic index(SDI)regions experienced a significant increase in ASIR,and regions with high and high-middle SDI experienced a significant decrease in ASMR.Global ASIR burden and ASMR burden were revealed to be concentrated mainly in higher-SDI and lower-SDI countries,respectively,with the concentration index in both sexes of 0.16(95%CI:0.13,0.19)and-0.14(95%CI:-0.18,-0.10)in 2021.Conclusions:Over the past three decades,the incidence burden of TC among the global WAP remarkably increased.International and regional policies for TC controls are supposed to be updated timely,to handle the current increasing burden and geographic disparities among WAP.展开更多
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
Clarifying the photosynthetic and population characteristics of conventional japonica rice at different yield levels is crucial for boosting yield and ensuring food security.Therefore,a two-year field trial with two c...Clarifying the photosynthetic and population characteristics of conventional japonica rice at different yield levels is crucial for boosting yield and ensuring food security.Therefore,a two-year field trial with two conventional japonica varieties was conducted at four planting densities:16 cm×30 cm(D1),14 cm×30 cm(D2),12 cm×30 cm(D3),and 10 cm×30 cm(D4).This study aimed to investigate how photosynthetic and population characteristics influence grain yield under varying planting densities.The results indicated that higher yields were primarily driven by increased grain weight and seed-setting rate(with a 9.68%‒11.40%higher single panicle weight),supported by optimized dry matter translocation and source-sink relationships.Elevated planting density(D2‒D4)enhanced panicle number and total spikelet number(by 3.91%‒15.00%)but reduced the number of spikelets per panicle,1000-grain weight,and photosynthetic efficiency due to mutual shading.Despite these trade-offs,yield increased by 4.10%‒12.42%under higher densities.The use of planting density D4 in japonica rice cultivation contributed to maximize yield.These findings provide important theoretical insights and practical significance for increasing the yield of conventional japonica rice and ensuring food security.展开更多
Varicella,a highly contagious respiratory infection caused by the varicella-zoster virus(VZV),predominantly affects children and is characterized by symptoms such as low-grade fever and vesicular rash[1,2].In China,va...Varicella,a highly contagious respiratory infection caused by the varicella-zoster virus(VZV),predominantly affects children and is characterized by symptoms such as low-grade fever and vesicular rash[1,2].In China,varicella remains prevalent,with a steady increase in incidence,peaking at 70.14 cases per 100,000 individuals in 2019[3].Although the number of reported outbreaks and cases from 2020 to 2022 was lower than those from 2006 to 2012 and 2013 to 2019,varicella continues to pose a significant public health challenge[3].展开更多
Purpose:ATLAS is a cross-sectional study aiming to investigate environmental and genetic determinants of athletic performance in healthy Greek competitive athletes(CA).This article presents the study design,investigat...Purpose:ATLAS is a cross-sectional study aiming to investigate environmental and genetic determinants of athletic performance in healthy Greek competitive athletes(CA).This article presents the study design,investigates the muscle strength performance(MSP)of 289 adult and teenage CA,exercisers,and physically inactive individuals(PI),and proposes predictive models of MSP for adults.Methods:Muscle maximal,speed,and explosive strength(MMS/MSS/MES)at unilateral maximal concentric flexion and extension contraction(FC/EC)were evaluated using Biodex System 3 PRO^(TM)at 60°/s,180°/s,and 300°/s,while additional performance markers were assessed through field ergometric testing.Participants were interviewed about their lifestyle,dietary habits,physical activity,injury,and medical history.Body composition was assessed via bioelectrical impedance.gDNA was extracted from biochemical samples and then genotyped.Statistical analysis was conducted using IBM SPSS Statistics v21.0 and R.Results:Age,fitness,and sex impacted correlations of MSP with body composition and anthropometric measurements(p<0.05).Among CA,females outperformed males in accuracy(p<0.001)while,males outperformed females in anaerobic power,MSP,speed,and endurance(p<0.001).Adult CA outperformed exercisers and PI in MMS,MSS,and MES(p<0.05).Multiple linear regression models,with predictors age,FFM,body extremity,training load explained the majority of variation in MMS(R^(2)_(adj):71.4%–88.9%),MSS(R^(2)_(adj):64.8%–78.4%),and MES(R^(2)_(adj):52.7%–68.4%)at EC,FC,and their mean(p<0.001).Conclusions:Muscle-strengthening strategies should be customized according to individual fitness levels,body composition,and anthropometric measurements.The innovative sex-specific regression models assessing MMS,MSS,and MES at EC and FC provide a framework for personalizing rehabilitation and skill-specific training strategies.展开更多
The United Nations Sustainable Development Goal(SDG) 2 aims to achieve Zero Hunger by 2030.However,global hunger and food insecurity have continued to rise at an alarming rate(UN 2023).Subtropical regions are home to ...The United Nations Sustainable Development Goal(SDG) 2 aims to achieve Zero Hunger by 2030.However,global hunger and food insecurity have continued to rise at an alarming rate(UN 2023).Subtropical regions are home to more than 30% of the world's population,predominantly in developing countries where per capita farmland and food supply are only 40% of those in developed nations(FAO 2018).Meeting the Zero Hunger target amid ongoing population growth in these regions requires a substantial increase in agricultural production while minimizing soil degradation and adverse ecological impacts.This challenge is shared by many countries across South Asia,Africa,and Central and South America.展开更多
Taking the rural low-income population of Zhejiang Province as its subject, this paper examines how to build a sustainable income-growth mechanism and identify feasible implementation paths within the context of the c...Taking the rural low-income population of Zhejiang Province as its subject, this paper examines how to build a sustainable income-growth mechanism and identify feasible implementation paths within the context of the common prosperity strategy. The research identifies key obstacles to income expansion, including an undiversified industrial structure, insufficient human capital, and a lack of robust social protection. These call for systemic solutions featuring institutional innovation, resource consolidation, and capability enhancement. Building on Zhejiang's experience as a common prosperity demonstration zone, the article constructs an integrated framework centered on four pillars: industrial empowerment, education upgrading, social security reinforcement, and digital coordination. It further offers concrete policy proposals involving the cultivation of localized industries, vocational skill training, enhanced safety nets, and the adoption of digital tools. The study thus offers both theoretical insights and practical paradigms for tackling the challenge of raising incomes in low-income rural areas.展开更多
BACKGROUND In an era leaning toward a personalized alignment of total knee arthroplasty,coronal plane alignment of the knee(CPAK)phenotypes for each population are studied;furthermore,other possible variables affectin...BACKGROUND In an era leaning toward a personalized alignment of total knee arthroplasty,coronal plane alignment of the knee(CPAK)phenotypes for each population are studied;furthermore,other possible variables affecting the alignment,such as ankle joint alignment,should be considered.AIM To determine CPAK distribution in the North African(Egyptian)population with knee osteoarthritis and to assess ankle joint line orientation(AJLO)adaptations across different CPAK types.METHODS A cross-sectional study was conducted on patients with primary knee osteoarthritis and normal ankle joints.Radiographic parameters included the mechanical lateral distal femoral angle,medial proximal tibial angle,and the derived calculations of joint line obliquity(JLO)and arithmetic hip-knee-ankle angle(aHKA).The tibial plafond horizontal angle(TPHA)was used for AJLO assessment,where 0°is neutral(type N),<0°is varus(type A),and>0°is valgus(type B).The nine CPAK types were further divided into 27 subtypes after incorporating the three AJLO types.RESULTS A total of 527 patients(1054 knees)were included for CPAK classification,and 435 patients(870 knees and ankles)for AJLO assessment.The mean age was 57.2±7.8 years,with 79.5%females.Most knees(76.4%)demonstrated varus alignment(mean aHKA was-5.51°±4.84°)and apex distal JLO(55.3%)(mean JLO was 176.43°±4.53°).CPAK types I(44.3%),IV(28.6%),and II(10%)were the most common.Regarding AJLO,70.2%of ankles exhibited varus orientation(mean TPHA was-5.21°±6.45°).The most frequent combined subtypes were CPAK type I-A(33.7%),IV-A(21.5%),and I-N(6.9%).A significant positive correlation was found between the TPHA and aHKA(r=0.40,P<0.001).CONCLUSION In this North African cohort,varus knee alignment with apex distal JLO and varus AJLO predominated.CPAK types I,IV,and II were the most common types,while subtypes I-A,IV-A,and I-N were commonly occurring after incorporating AJLO types;furthermore,the AJLO was significantly correlated to aHKA.展开更多
The Fujian oyster(Crassostrea angulata) is an economically significant shellfish species distributed mainly along the Fujian coast, Southeast China. However, its genetic diversity and structure remain unclear. The mai...The Fujian oyster(Crassostrea angulata) is an economically significant shellfish species distributed mainly along the Fujian coast, Southeast China. However, its genetic diversity and structure remain unclear. The main distribution area of the C. angulata is located in Fujian, South China. In total, 420 C. angulata were collected from 14 natural habitats(populations) along the Fujian coast, and their genetic diversity and structure were analyzed in the mitochondrial COI and nuclear gene ITS2 sequences. Results reveal that all the 14 populations of C. angulata exhibited high levels of genetic diversity, with a total of 57(haplotype diversity: 0.811±0.016) and 124(haplotype diversity: 0.912±0.007) haplotypes revealed by COI and ITS2, respectively. Notably, significant intermediate level of genetic differentiations between the Ningde Zhujiang(ZJ) population(FS T by COI: 0.035–0.142, P<0.05;FS T by ITS2: 0.078–0.123, P<0.05) with other populations were observed for the first time, which is also supported by the results of molecular variance analysis(FC T by COI: 0.105, P<0.05;FC T by ITS2: 0.086, P<0.05) and the clustering of the ZJ population into distinct branches in the interpopulation genetic differentiation tree. Furthermore, the evolutionary tree and haplotype network analyses do not support the formation of a clear geographical genealogical structure among these 14 populations. In addition, the population dynamics analysis suggests that the C. angulata may have undergone expansion during the third ice age of the Pleistocene. These results provide a reference for the preservation and further genetic improvement of C. angulata.展开更多
Stichopus chloronotus is a tropical sea cucumber with facultative asexual reproduction in the Indo-Western Pacific,yet its wild populations are decreasing due to extensive harvesting.Understanding the species’genetic...Stichopus chloronotus is a tropical sea cucumber with facultative asexual reproduction in the Indo-Western Pacific,yet its wild populations are decreasing due to extensive harvesting.Understanding the species’genetic characteristics is essential for effective management and conservation.To develop novel microsatellite markers and assess the genetic diversity,clonality,and genetic structure of eight populations of S.chloronotus in the South China Sea,193 individuals from eight populations across Wuzhizhou and Fenjiezhou(Boundary)islands were analyzed using nine newly developed microsatellite markers and five previously established markers.RNA-Seq was employed to obtained 62662 unigenes and identified 16926 microsatellite loci.Fourteen polymorphic microsatellite loci were developed,of which 11 were highly polymorphic(polymorphic information content>0.5).The number of alleles(N_(a))ranged from 3 to 6 per locus,and the average Shannon diversity index(I)was 1.107.All the populations exhibited asexual reproduction,with regional variations in reproductive modes.Asexual reproduction was predominant in the northwestern Wuzhizhou Island population(SY 7)and the Fenjiezhou Island population(LS 8),where four and five predominant clones represented more than 89%of the individuals,which led to reduced genetic diversity.Overall,genetic diversity was moderately low,with significant genetic differentiation among populations(F_(ST)=0.33;P<0.001),suggesting limited gene flow(the number of migrants(N_(m))<1).These findings highlight the role of reproductive strategies in shaping fine-scale genetic differentiation in S.chloronotus.The limited recruitment success of sexually produced larvae and habitat heterogeneity likely constrain clone dispersal,contributing to distinct genetic restructuring.This study provided key insights into the interplay between reproductive strategies and genetic patterns in sea cucumbers,offering a scientific basis for targeted conservation efforts.展开更多
The Saccostrea mordax Gould,1850 is a typical intertidal species,whose genetic differentiation is influenced by various factors,including geological and climatic changes.To explore the genetic structure and historical...The Saccostrea mordax Gould,1850 is a typical intertidal species,whose genetic differentiation is influenced by various factors,including geological and climatic changes.To explore the genetic structure and historical population characteristics of Saccostrea mordax,we sequenced the mitochondrial cytochrome c oxidase subunit I(COI)gene from 58 specimens sampled from four locations in the western Pacific.Additionally,103 individuals from the Persian Gulf and western Pacific(from databases)were included for phylogenetic analysis.The Bayesian Inference tree showed that all specimens were divided into two clades,i.e.,the Persian Gulf population and the western Pacific population.Spatial molecular variance analysis indicated significant genetic differentiation between the two populations,and isolation by distance analysis revealed a positive correlation between genetic differentiation and geographic distance.Neutrality tests and Bayesian Skyline Plot suggested that both populations underwent expansions during the late Pleistocene.This study revealed the population history of Saccostrea mordax and described a new lineage,Saccostrea mordax lineage D,providing a foundation for understanding oyster biodiversity formation and genetic resource conservation.展开更多
We investigate an optimal harvesting problem for age-structured species,in which elder individuals are more competitive than younger ones,and the population is modeled by a highly nonlinear integro-partial differentia...We investigate an optimal harvesting problem for age-structured species,in which elder individuals are more competitive than younger ones,and the population is modeled by a highly nonlinear integro-partial differential equation with a global feedback boundary condition.The existence of optimal strategies is established by means of compactness and maximizing sequences,and the maximum principle obtained via an adjoint system,tangent-normal cones and a new continuity result.In addition,some numerical experiments are presented to show the effects of the price function and younger's weight on the optimal profits.展开更多
In this paper,we study the nonstationary population control systems:We regard the female-sum fertility rate β(t) as control auction ac judge its optimality by"norm minimum",and discuss the minimum norm cont...In this paper,we study the nonstationary population control systems:We regard the female-sum fertility rate β(t) as control auction ac judge its optimality by"norm minimum",and discuss the minimum norm control problems for the above population control systems.Utilizing space L2(0,T)’s reflexivity,smoothness and strict convexity,we prove the existence,the uniqueness and the approximation property of the minimum norm control for the nonstationary population control systems and give the corresponding optimality conditions by means of the methods of the dial mapping of Banach space.展开更多
In this paper,we discuss the optimal control of growth rate for a class of population systems governed by nonlinear degenerate parabolic equations.Given an ap-propriate cost functional,we prove the existence of the op...In this paper,we discuss the optimal control of growth rate for a class of population systems governed by nonlinear degenerate parabolic equations.Given an ap-propriate cost functional,we prove the existence of the optimal growth rate and give some necessary conditions for optimal growth rate.展开更多
In this paper, we present the compensated stochastic θ method for stochastic age-dependent delay population systems（SADDPSs） with Poisson jumps. The definition of mean-square stability of the numerical solution is ...In this paper, we present the compensated stochastic θ method for stochastic age-dependent delay population systems（SADDPSs） with Poisson jumps. The definition of mean-square stability of the numerical solution is given and a sufficient condition for mean-square stability of the numerical solution is derived. It is shown that the compensated stochastic θ method inherits stability property of the numerical solutions. Finally,the theoretical results are also confirmed by a numerical experiment.展开更多
A field experiment was conducted to study the combined effect of nutrient andpest managements on soil biomass phospholipid contents, functional biodiversity and substrateutilization patterns of soil microbial populati...A field experiment was conducted to study the combined effect of nutrient andpest managements on soil biomass phospholipid contents, functional biodiversity and substrateutilization patterns of soil microbial populations in hybrid rice cropping system. The mineral N, Pand K fertilizers (as urea, calcium superphosphate and KCl respectively) were incorporated at 100,25, and 100 kg ha^(-1), respectively, and the various pesticides were applied at the recommendedrates. The results of the experiment demonstrated a decline in the microbial abundance and soilmicrobial biomass phospholipid contents with the advancement of crop growth, and significant changesin substrate utilization pattern of soil microbial population studied were observed with differentmanagement practices and at different growth stages. The principal component analysis (PCA) usingall 95-carbon sources (BIOLOG plates) gave good differentiation among the treatments, indicatingthat they have different patterns of carbon utilization under different habitats. The data showedthat diversity in microbial community continuously changed with the progression in crop stage,particularly at physiological maturity (PM) stage that was evident from the utilization of differentcarbon sources at various crop stages.展开更多
The floating population has become the main driver of urban population excessive growth in China＇s mega cities. Urban transit system （UTS） is a significant factor in population spatial distributions within urban ar...The floating population has become the main driver of urban population excessive growth in China＇s mega cities. Urban transit system （UTS） is a significant factor in population spatial distributions within urban areas, especially rapid and high-capacity transit systems. This paper analyzes the causal effects of the extension of expressways and subways between 2000 and 2010 in the Beijing Metropolitan Area （BMA）, focusing on the group differences between the local residents and the floating population. Due to the endogeneity of transportation improvements and population growth, Instrumental Variable （IV） regression model is applied to avoid this problem. The results show the local residents increased in the inner suburbs but decreased in the city center, while the floating population increased in the majority areas. IV regression results show that the extension of urban transit systems had statistically significant impacts on population growth across the BMA, The results also show that the extension of urban subway system had more effects on the floating population than the local residents across the BMA. It is mainly caused by the rather low fare of urban subway system. This implies that the excessive subsidy on urban subway system could result in ex- cessive floating population growth and residential differentiation, even residential segregation Hence, it is necessary to plan and design reasonable and scientific urban transit systems in order to advance reasonable population size and promote residential integration. Moreover, the regional analysis shows that the effects of urban transportation improvements on the local residents are not statistically significant in the inner suburbs. It implies that urban transportation improvements had limited effects on inducing people to move to suburban areas and controlling center city＇s population in Beijing. Therefore, it should be stressed the differenti- ated effects of urban transportation improvements on population distribution in the process of urban planning and population control.展开更多
文摘The population system is the only subsystem tha has charecteristic of subjectivity in theregional PRED system. Influenced by the particular status quo of natural resources and environmentconditions, the population subsystem of the Qaidam Basin is very different from those of otherregions'. Based on the on-the-spot investigation to the Qaidam Basin in July 1997, the authors of thispaper sum up several characters of the population subsystem of the Basin. (1) Population mainlyconsisting of the big volume of immigrants and floating population increases very fast. (2) With highpopulation mobility there was great discrepany between the actual number of population (aggregatepopulation) and the statidtical population. (3) Degree of urbanization is very high, and employmentconcentrates mainly on the industrial and teftiary industrial sectors. (4) Sex ratio remains veryunbalanced, especially in the youth group of population which exerts high pressure on employmentand training because of the young age structure. (5) Population quality is relatively high as a wholeWhile educahonal level characterizes the undeveloped regions. In order to predict the futurepopulation of the Basin. according to the characters of population system, this paper puts forward away called dividing-steps-forecast-sum to do the prediction till 2050, use both modeling forecastingmethod and empirical evaluation. The results indicated that the total population of the Basin whllreach 1 .28 million in 2050. Among them, the natural increment and immigrant and floating incrementoccupy 34.99% and 60.86%, respectively, with another 4.13% of special population. In terms ofcharactedstics of population and predicted results as well as the status quo of natural resources andenvironment this paper suggests several thoughts to optimize and adjust the population system of theQaidam Basin. They are, firsuy, to control the number of population as well as improve thepopulation quality, and secondly, to reghate the floating population to assort them withsocioeconomic development in the Basin. Above all, the most important step is to throw high level ofscience and techniqte into the Basin's socioeconomic system to enhance the carrying capacity ofresources and environment and improve the coordinated relationship among population, resources andcnvironment
文摘In this paper,a population system with cross-diffusion and habitat complexity is selected as study object.We investigate that how cross-diffusion and habitat complexity destabilize the otherwise stable periodic solutions of the ODEs to generate the new abundant spatial Turing patterns.By utilizing the local Hopf bifurcation theorem and perturbation theory,we establish a formula to determine the Turing instability of periodic solutions of the population system withcross-diffusion and habitat complexity.Finally,numerical simulations are performed to verify theoretical analysis,simultaneously,we verify the formation process of spatial Turing patterns when the cross-diffusion coefficients and habitat complexity change.
基金project funded by the Natural Science Foundation of Ningxia Province(2023AAC03114)the First-class Discipline Construction Project of Ningxia Colleges and Universities(NXYLXK2021A03)the Graduate Innovation Project of Ningxia University(CXXM2023-10).
文摘In this paper,we consider the optimal boundary control problem of a two-species competitive system with time delay and size structure in a polluted environment.First,the well posedness of the system is studied by using the characteristic line method and the fixed point principle.Second,the necessary conditions for optimal boundary control are obtained by conjugate system and normal cone property.Finally,the existence and uniqueness of the optimal strategy are proved by Ekeland variational principle.
文摘Objective:This study aims to estimate the thyroid cancer(TC)burden and trends from 1990 and 2021 among working-age population(WAP),at the global,regional,and national levels.Methods:Based on the Global Burden of Disease 2021 study,this cross-sectional study included data on TC incidence and mortality for WAP aged 15-64 years across 204 countries and territories from 1990 to 2021.The age-standardized incidence rate(ASIR)and age-standardized mortality rate(ASMR)of TC were used to estimate the disease burden.Temporal trends of ASIR and ASMR were estimated by average annual percentage changes(AAPCs)based on age-period-cohort models.Relative inequality of TC burden across 204 countries was estimated by the slope index of concentration index.Results:Globally,ASIR of TC increased from 2.27 per 100,000 population to 3.41 per 100,000 population from1990 to 2021,with AAPC of 1.59%[95%confidence interval(95%CI):1.54,1.64];in contrast,ASMRs were stable at 0.31 per 100,000 population.Females had a higher disease burden than males,and adults aged 45-64 years accounted for more than 55%of the TC cases.Across regions and countries,North Africa and Comoros experienced the highest increase in ASIR,with AAPCs of 2.97%and 7.73%,respectively.All socio-demographic index(SDI)regions experienced a significant increase in ASIR,and regions with high and high-middle SDI experienced a significant decrease in ASMR.Global ASIR burden and ASMR burden were revealed to be concentrated mainly in higher-SDI and lower-SDI countries,respectively,with the concentration index in both sexes of 0.16(95%CI:0.13,0.19)and-0.14(95%CI:-0.18,-0.10)in 2021.Conclusions:Over the past three decades,the incidence burden of TC among the global WAP remarkably increased.International and regional policies for TC controls are supposed to be updated timely,to handle the current increasing burden and geographic disparities among WAP.
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funded by the National Key R&D Program of China (Grant No. 2024YFD2300301)the National Natural Science Foundation of China (Grant Nos. 32472223 and 31901447)+1 种基金the Priority Academic Program Development of Jiangsu Higher Education Institutionsthe Qinglan Project of Jiangsu Province, China
文摘Clarifying the photosynthetic and population characteristics of conventional japonica rice at different yield levels is crucial for boosting yield and ensuring food security.Therefore,a two-year field trial with two conventional japonica varieties was conducted at four planting densities:16 cm×30 cm(D1),14 cm×30 cm(D2),12 cm×30 cm(D3),and 10 cm×30 cm(D4).This study aimed to investigate how photosynthetic and population characteristics influence grain yield under varying planting densities.The results indicated that higher yields were primarily driven by increased grain weight and seed-setting rate(with a 9.68%‒11.40%higher single panicle weight),supported by optimized dry matter translocation and source-sink relationships.Elevated planting density(D2‒D4)enhanced panicle number and total spikelet number(by 3.91%‒15.00%)but reduced the number of spikelets per panicle,1000-grain weight,and photosynthetic efficiency due to mutual shading.Despite these trade-offs,yield increased by 4.10%‒12.42%under higher densities.The use of planting density D4 in japonica rice cultivation contributed to maximize yield.These findings provide important theoretical insights and practical significance for increasing the yield of conventional japonica rice and ensuring food security.
文摘Varicella,a highly contagious respiratory infection caused by the varicella-zoster virus(VZV),predominantly affects children and is characterized by symptoms such as low-grade fever and vesicular rash[1,2].In China,varicella remains prevalent,with a steady increase in incidence,peaking at 70.14 cases per 100,000 individuals in 2019[3].Although the number of reported outbreaks and cases from 2020 to 2022 was lower than those from 2006 to 2012 and 2013 to 2019,varicella continues to pose a significant public health challenge[3].
文摘Purpose:ATLAS is a cross-sectional study aiming to investigate environmental and genetic determinants of athletic performance in healthy Greek competitive athletes(CA).This article presents the study design,investigates the muscle strength performance(MSP)of 289 adult and teenage CA,exercisers,and physically inactive individuals(PI),and proposes predictive models of MSP for adults.Methods:Muscle maximal,speed,and explosive strength(MMS/MSS/MES)at unilateral maximal concentric flexion and extension contraction(FC/EC)were evaluated using Biodex System 3 PRO^(TM)at 60°/s,180°/s,and 300°/s,while additional performance markers were assessed through field ergometric testing.Participants were interviewed about their lifestyle,dietary habits,physical activity,injury,and medical history.Body composition was assessed via bioelectrical impedance.gDNA was extracted from biochemical samples and then genotyped.Statistical analysis was conducted using IBM SPSS Statistics v21.0 and R.Results:Age,fitness,and sex impacted correlations of MSP with body composition and anthropometric measurements(p<0.05).Among CA,females outperformed males in accuracy(p<0.001)while,males outperformed females in anaerobic power,MSP,speed,and endurance(p<0.001).Adult CA outperformed exercisers and PI in MMS,MSS,and MES(p<0.05).Multiple linear regression models,with predictors age,FFM,body extremity,training load explained the majority of variation in MMS(R^(2)_(adj):71.4%–88.9%),MSS(R^(2)_(adj):64.8%–78.4%),and MES(R^(2)_(adj):52.7%–68.4%)at EC,FC,and their mean(p<0.001).Conclusions:Muscle-strengthening strategies should be customized according to individual fitness levels,body composition,and anthropometric measurements.The innovative sex-specific regression models assessing MMS,MSS,and MES at EC and FC provide a framework for personalizing rehabilitation and skill-specific training strategies.
文摘The United Nations Sustainable Development Goal(SDG) 2 aims to achieve Zero Hunger by 2030.However,global hunger and food insecurity have continued to rise at an alarming rate(UN 2023).Subtropical regions are home to more than 30% of the world's population,predominantly in developing countries where per capita farmland and food supply are only 40% of those in developed nations(FAO 2018).Meeting the Zero Hunger target amid ongoing population growth in these regions requires a substantial increase in agricultural production while minimizing soil degradation and adverse ecological impacts.This challenge is shared by many countries across South Asia,Africa,and Central and South America.
文摘Taking the rural low-income population of Zhejiang Province as its subject, this paper examines how to build a sustainable income-growth mechanism and identify feasible implementation paths within the context of the common prosperity strategy. The research identifies key obstacles to income expansion, including an undiversified industrial structure, insufficient human capital, and a lack of robust social protection. These call for systemic solutions featuring institutional innovation, resource consolidation, and capability enhancement. Building on Zhejiang's experience as a common prosperity demonstration zone, the article constructs an integrated framework centered on four pillars: industrial empowerment, education upgrading, social security reinforcement, and digital coordination. It further offers concrete policy proposals involving the cultivation of localized industries, vocational skill training, enhanced safety nets, and the adoption of digital tools. The study thus offers both theoretical insights and practical paradigms for tackling the challenge of raising incomes in low-income rural areas.
基金approved by Institutional Review Board of Faculty of Medicine in Assiut University,No.04-2024-300470.
文摘BACKGROUND In an era leaning toward a personalized alignment of total knee arthroplasty,coronal plane alignment of the knee(CPAK)phenotypes for each population are studied;furthermore,other possible variables affecting the alignment,such as ankle joint alignment,should be considered.AIM To determine CPAK distribution in the North African(Egyptian)population with knee osteoarthritis and to assess ankle joint line orientation(AJLO)adaptations across different CPAK types.METHODS A cross-sectional study was conducted on patients with primary knee osteoarthritis and normal ankle joints.Radiographic parameters included the mechanical lateral distal femoral angle,medial proximal tibial angle,and the derived calculations of joint line obliquity(JLO)and arithmetic hip-knee-ankle angle(aHKA).The tibial plafond horizontal angle(TPHA)was used for AJLO assessment,where 0°is neutral(type N),<0°is varus(type A),and>0°is valgus(type B).The nine CPAK types were further divided into 27 subtypes after incorporating the three AJLO types.RESULTS A total of 527 patients(1054 knees)were included for CPAK classification,and 435 patients(870 knees and ankles)for AJLO assessment.The mean age was 57.2±7.8 years,with 79.5%females.Most knees(76.4%)demonstrated varus alignment(mean aHKA was-5.51°±4.84°)and apex distal JLO(55.3%)(mean JLO was 176.43°±4.53°).CPAK types I(44.3%),IV(28.6%),and II(10%)were the most common.Regarding AJLO,70.2%of ankles exhibited varus orientation(mean TPHA was-5.21°±6.45°).The most frequent combined subtypes were CPAK type I-A(33.7%),IV-A(21.5%),and I-N(6.9%).A significant positive correlation was found between the TPHA and aHKA(r=0.40,P<0.001).CONCLUSION In this North African cohort,varus knee alignment with apex distal JLO and varus AJLO predominated.CPAK types I,IV,and II were the most common types,while subtypes I-A,IV-A,and I-N were commonly occurring after incorporating AJLO types;furthermore,the AJLO was significantly correlated to aHKA.
基金Supported by the National Natural Science Foundation of China(No.32172979)the Natural Science Foundation of Fujian Province(No.2021J05159)the 2023 Special Program for Promoting High-Quality Development of Marine and Fishery Industry in Fujian Province(No.PJHYF-L-2023-2)。
文摘The Fujian oyster(Crassostrea angulata) is an economically significant shellfish species distributed mainly along the Fujian coast, Southeast China. However, its genetic diversity and structure remain unclear. The main distribution area of the C. angulata is located in Fujian, South China. In total, 420 C. angulata were collected from 14 natural habitats(populations) along the Fujian coast, and their genetic diversity and structure were analyzed in the mitochondrial COI and nuclear gene ITS2 sequences. Results reveal that all the 14 populations of C. angulata exhibited high levels of genetic diversity, with a total of 57(haplotype diversity: 0.811±0.016) and 124(haplotype diversity: 0.912±0.007) haplotypes revealed by COI and ITS2, respectively. Notably, significant intermediate level of genetic differentiations between the Ningde Zhujiang(ZJ) population(FS T by COI: 0.035–0.142, P<0.05;FS T by ITS2: 0.078–0.123, P<0.05) with other populations were observed for the first time, which is also supported by the results of molecular variance analysis(FC T by COI: 0.105, P<0.05;FC T by ITS2: 0.086, P<0.05) and the clustering of the ZJ population into distinct branches in the interpopulation genetic differentiation tree. Furthermore, the evolutionary tree and haplotype network analyses do not support the formation of a clear geographical genealogical structure among these 14 populations. In addition, the population dynamics analysis suggests that the C. angulata may have undergone expansion during the third ice age of the Pleistocene. These results provide a reference for the preservation and further genetic improvement of C. angulata.
基金Supported by the National Key Research and Development Program of China(Nos.2022YFD2401305,2022YFD2401303)the National Natural Science Foundation of China(Nos.42166005,42076097)。
文摘Stichopus chloronotus is a tropical sea cucumber with facultative asexual reproduction in the Indo-Western Pacific,yet its wild populations are decreasing due to extensive harvesting.Understanding the species’genetic characteristics is essential for effective management and conservation.To develop novel microsatellite markers and assess the genetic diversity,clonality,and genetic structure of eight populations of S.chloronotus in the South China Sea,193 individuals from eight populations across Wuzhizhou and Fenjiezhou(Boundary)islands were analyzed using nine newly developed microsatellite markers and five previously established markers.RNA-Seq was employed to obtained 62662 unigenes and identified 16926 microsatellite loci.Fourteen polymorphic microsatellite loci were developed,of which 11 were highly polymorphic(polymorphic information content>0.5).The number of alleles(N_(a))ranged from 3 to 6 per locus,and the average Shannon diversity index(I)was 1.107.All the populations exhibited asexual reproduction,with regional variations in reproductive modes.Asexual reproduction was predominant in the northwestern Wuzhizhou Island population(SY 7)and the Fenjiezhou Island population(LS 8),where four and five predominant clones represented more than 89%of the individuals,which led to reduced genetic diversity.Overall,genetic diversity was moderately low,with significant genetic differentiation among populations(F_(ST)=0.33;P<0.001),suggesting limited gene flow(the number of migrants(N_(m))<1).These findings highlight the role of reproductive strategies in shaping fine-scale genetic differentiation in S.chloronotus.The limited recruitment success of sexually produced larvae and habitat heterogeneity likely constrain clone dispersal,contributing to distinct genetic restructuring.This study provided key insights into the interplay between reproductive strategies and genetic patterns in sea cucumbers,offering a scientific basis for targeted conservation efforts.
基金Supported by the Key R&D Program of Shandong Province(No.2023CXGC010411)the National Key R&D Program of China(Nos.2023YFD2400800,2022YFD2401301,2022FY100304)+2 种基金the National Natural Science Foundation of China(Nos.42076092,41906083,41776179)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB42000000)the Earmarked Fund for Modern Agro-industry Technology Research System(No.CARS-47)。
文摘The Saccostrea mordax Gould,1850 is a typical intertidal species,whose genetic differentiation is influenced by various factors,including geological and climatic changes.To explore the genetic structure and historical population characteristics of Saccostrea mordax,we sequenced the mitochondrial cytochrome c oxidase subunit I(COI)gene from 58 specimens sampled from four locations in the western Pacific.Additionally,103 individuals from the Persian Gulf and western Pacific(from databases)were included for phylogenetic analysis.The Bayesian Inference tree showed that all specimens were divided into two clades,i.e.,the Persian Gulf population and the western Pacific population.Spatial molecular variance analysis indicated significant genetic differentiation between the two populations,and isolation by distance analysis revealed a positive correlation between genetic differentiation and geographic distance.Neutrality tests and Bayesian Skyline Plot suggested that both populations underwent expansions during the late Pleistocene.This study revealed the population history of Saccostrea mordax and described a new lineage,Saccostrea mordax lineage D,providing a foundation for understanding oyster biodiversity formation and genetic resource conservation.
基金the National Natural Science Foundation of China(11871185)Zhejiang Provincial Natural Science Foundation of China(LY18A010010).
文摘We investigate an optimal harvesting problem for age-structured species,in which elder individuals are more competitive than younger ones,and the population is modeled by a highly nonlinear integro-partial differential equation with a global feedback boundary condition.The existence of optimal strategies is established by means of compactness and maximizing sequences,and the maximum principle obtained via an adjoint system,tangent-normal cones and a new continuity result.In addition,some numerical experiments are presented to show the effects of the price function and younger's weight on the optimal profits.
文摘In this paper,we study the nonstationary population control systems:We regard the female-sum fertility rate β(t) as control auction ac judge its optimality by"norm minimum",and discuss the minimum norm control problems for the above population control systems.Utilizing space L2(0,T)’s reflexivity,smoothness and strict convexity,we prove the existence,the uniqueness and the approximation property of the minimum norm control for the nonstationary population control systems and give the corresponding optimality conditions by means of the methods of the dial mapping of Banach space.
基金This research is supported by the National Natural Science Foundation of China.
文摘In this paper,we discuss the optimal control of growth rate for a class of population systems governed by nonlinear degenerate parabolic equations.Given an ap-propriate cost functional,we prove the existence of the optimal growth rate and give some necessary conditions for optimal growth rate.
基金Supported by Major Innovation Projects for Building First-class Universities in China’s Western Region(No.ZKZD2017009)(China)
文摘In this paper, we present the compensated stochastic θ method for stochastic age-dependent delay population systems（SADDPSs） with Poisson jumps. The definition of mean-square stability of the numerical solution is given and a sufficient condition for mean-square stability of the numerical solution is derived. It is shown that the compensated stochastic θ method inherits stability property of the numerical solutions. Finally,the theoretical results are also confirmed by a numerical experiment.
基金the National Natural Science Foundation of China.
文摘A field experiment was conducted to study the combined effect of nutrient andpest managements on soil biomass phospholipid contents, functional biodiversity and substrateutilization patterns of soil microbial populations in hybrid rice cropping system. The mineral N, Pand K fertilizers (as urea, calcium superphosphate and KCl respectively) were incorporated at 100,25, and 100 kg ha^(-1), respectively, and the various pesticides were applied at the recommendedrates. The results of the experiment demonstrated a decline in the microbial abundance and soilmicrobial biomass phospholipid contents with the advancement of crop growth, and significant changesin substrate utilization pattern of soil microbial population studied were observed with differentmanagement practices and at different growth stages. The principal component analysis (PCA) usingall 95-carbon sources (BIOLOG plates) gave good differentiation among the treatments, indicatingthat they have different patterns of carbon utilization under different habitats. The data showedthat diversity in microbial community continuously changed with the progression in crop stage,particularly at physiological maturity (PM) stage that was evident from the utilization of differentcarbon sources at various crop stages.
基金Key Project of National Natural Science Foundation of China, No.41230632, No.71433008 Doctoral Project of Tianjin Normal University, No.52XB 1621Acknowledgments We thank Prof. Michael J. White in Brown University for the comments and suggestions on this research. We also thank the Writing Center in Brown University, Joan and John Kenower for the language revision.
文摘The floating population has become the main driver of urban population excessive growth in China＇s mega cities. Urban transit system （UTS） is a significant factor in population spatial distributions within urban areas, especially rapid and high-capacity transit systems. This paper analyzes the causal effects of the extension of expressways and subways between 2000 and 2010 in the Beijing Metropolitan Area （BMA）, focusing on the group differences between the local residents and the floating population. Due to the endogeneity of transportation improvements and population growth, Instrumental Variable （IV） regression model is applied to avoid this problem. The results show the local residents increased in the inner suburbs but decreased in the city center, while the floating population increased in the majority areas. IV regression results show that the extension of urban transit systems had statistically significant impacts on population growth across the BMA, The results also show that the extension of urban subway system had more effects on the floating population than the local residents across the BMA. It is mainly caused by the rather low fare of urban subway system. This implies that the excessive subsidy on urban subway system could result in ex- cessive floating population growth and residential differentiation, even residential segregation Hence, it is necessary to plan and design reasonable and scientific urban transit systems in order to advance reasonable population size and promote residential integration. Moreover, the regional analysis shows that the effects of urban transportation improvements on the local residents are not statistically significant in the inner suburbs. It implies that urban transportation improvements had limited effects on inducing people to move to suburban areas and controlling center city＇s population in Beijing. Therefore, it should be stressed the differenti- ated effects of urban transportation improvements on population distribution in the process of urban planning and population control.
