AN OPTIMAL CONTROL PROBLEM FOR A LOTKA-VOLTERRA COMPETITION MODEL WITH CHEMO-REPULSION

In this paper we study a bilinear optimal control problem for a diffusive Lotka-Volterra competition model with chemo-repulsion in a bounded domain of ℝ^(ℕ),N=2,3.This model describes the competition of two species in which one of them avoid encounters with rivals through a chemo-repulsion mechanism.We prove the existence and uniqueness of weak-strong solutions,and then we analyze the existence of a global optimal solution for a related bilinear optimal control problem,where the control is acting on the chemical signal.Posteriorly,we derive first-order optimality conditions for local optimal solutions using the Lagrange multipliers theory.Finally,we propose a discrete approximation scheme of the optimality system based on the gradient method,which is validated with some computational experiments.

ENTIRE SOLUTIONS OF LOTKA-VOLTERRA COMPETITION SYSTEMS WITH NONLOCAL DISPERSAL

This paper is mainly concerned with entire solutions of the following two-species Lotka-Volterra competition system with nonlocal(convolution)dispersals:{u_(t)=k*u-u+u(1-u-av),x∈R,t∈R,vt=d(k*v-v)+rv(1-v-bu),c∈R,t∈R.(0.1)Here a≠1,b≠1,d,and r are positive constants.By studying the eigenvalue problem of(0.1)linearized at(ϕc(ξ),0),we construct a pair of super-and sub-solutions for(0.1),and then establish the existence of entire solutions originating from(ϕc(ξ),0)as t→−∞,whereϕc denotes the traveling wave solution of the nonlocal Fisher-KPP equation ut=k*u−u+u(1−u).Moreover,we give a detailed description on the long-time behavior of such entire solutions as t→∞.Compared to the known works on the Lotka-Volterra competition system with classical diffusions,this paper overcomes many difficulties due to the appearance of nonlocal dispersal operators.

Existence of Two Limit Cycles in Zeeman’s Class 30 for 3D Lotka-Volterra Competitive System

Gyllenberg and Yan(Discrete Contin Dyn Syst Ser B 11(2):347–352,2009)presented a system in Zeeman’s class 30 of 3-dimensional Lotka-Volterra(3D LV)competitive systems to admit at least two limit cycles,one of which is generated by the Hopf bifurcation and the other is obtained by the Poincaré-Bendixson theorem.Yu et al.(J Math Anal Appl 436:521–555,2016,Sect.3.4)recalculated the first Liapunov coefficient of Gyllenberg and Yan’s system to be positive,rather than negative as in Gyllenberg and Yan(2009),and pointed out that the Poincaré-Bendixson theorem is not applicable for that system.Jiang et al.(J Differ Equ 284:183–218,2021,p.213)proposed an open question:“whether Zeeman’s class 30 can be rigorously proved to admit at least two limit cycles by the Hopf theorem and the Poincaré-Bendixson theorem?”This paper provides four systems in Zeeman’s class 30 to admit at least two limit cycles by the Hopf theorem and the Poincaré-Bendixson theorem and gives an answer to the above question.

Competitive oxidation behavior of Ni-based superalloy GH4738 at extreme temperature

A high thrust-to-weight ratio poses challenges to the high-temperature performance of Ni-based superalloys. The oxidation behavior of GH4738 at extreme temperatures has been investigated by isothermal and non-isothermal experiments. As a result of the competitive diffusion of alloying elements, the oxide scale included an outermost porous oxide layer (OOL), an inner relatively dense oxide layer (IOL), and an internal oxide zone (IOZ), depending on the temperature and time. A high temperature led to the formation of large voids at the IOL/IOZ interface. At 1200℃, the continuity of the Cr-rich oxide layer in the IOL was destroyed, and thus, spallation occurred. Extension of oxidation time contributed to the size of Al-rich oxide particles with the increase in the IOZ. Based on this finding,the oxidation kinetics of GH4738 was discussed, and the corresponding oxidation behavior at 900-1100℃ was predicted.

基于Lotka-Volterra模型的数字经济与实体经济共生模式研究

为推进数字经济与实体经济深度融合,促进区域经济高质量发展,依据共生理论,论文从资源环境承载力角度,构建数字经济与实体经济的共生系统,基于Lotka-Volterra模型分析数字经济与实体经济的共生模式,并运用熵值-DEMATEL法探析实现数字经济与实体经济互惠共生的关键因素。实证研究结果表明:存在以互惠共生为主的多种共生模式,以实体经济的促进作用为主要表现形式;共生模式与数字经济、实体经济发展水平无明显关联;数字经济与实体经济的共生呈现出互惠共生—单利共生/竞争互害—互惠共生的交替上升规律;数字经济发展类因素是实现数字经济与实体经济互惠共生的关键因素,生态环境类因素是实现互惠共生发展中最为明显的被影响因素。

一类分数阶Lotka-Volterra系统的动力学研究

本文建立了一个新的分数阶Lotka-Volterra模型.首先,我们考虑所涉及的分数阶Lotka-Volterra模型的存在性、唯一性和非负性.其次,通过分析特征方程将时滞视为分岔参数,建立一个新的充分条件来保证系统的稳定性和Hopf分岔的出现.

具有时滞和线性收获项的三维Lotka-Volterra合作系统的Hopf分支

针对三维Lotka-Volterra合作系统的Hopf分支进行了研究。首先,在三维Lotka-Volterra合作系统的基础上,引入时滞项及线性收获项对该系统进行改进;其次,以时滞τ作为分支参数,对改进后系统的局部Hopf分支的存在性进行分析,给出使系统在正平衡点处产生Hopf分支的临界值;然后,利用中心流形定理和规范型理论计算出Hopf分支方向及周期解稳定性的公式;最后,进行数值模拟,根据数值模拟的结果,验证了理论的可行性。结果表明,当时滞τ从0一直增加到超过临界值时,系统的正平衡点由稳定状态变为不稳定状态,且在正平衡点处产生Hopf分支。说明时滞影响了系统的动力学行为,使其动力学性质更加复杂。

基于Lotka-Volterra种群动态模型的水生动物性别比例变化研究

水生动物的性别比例会受遗传因素与外界环境、激素的影响,其具有适应性别比例变异的特征,且性别比例变化对种群自身及其他物种都有一定影响。主要从物种间的内部机制与外部资源环境因素两方面论述。通过已知性别决定因素,构造性别比例变化与资源可用性相关函数,考虑性别比例变化与生存环境面积的影响,建立基于Lotka-Volterra的系统动态模型。本文以海七鳃鳗为例,运用模型进行研究,研究得到其在性别比例变化下种群数量变化曲线随时间呈周期性,且猎食者的数量波动相比于猎物的数量呈现约四分之一个周期的滞后效应。

Competitive effect, but not competitive response, varies along a climatic gradient depending on tree species identity

Background: Understanding the role of species identity in interactions among individuals is crucial for assessing the productivity and stability of mixed forests over time. However, there is limited knowledge concerning the variation in competitive effect and response of different species along climatic gradients. In this study, we investigated the importance of climate, tree size, and competition on the growth of three tree species: spruce(Picea abies), fir(Abies alba), and beech(Fagus sylvatica), and examined their competitive response and effect along a climatic gradient.Methods: We selected 39 plots distributed across the European mountains with records of the position and growth of 5,759 individuals. For each target species, models relating tree growth to tree size, climate and competition were proposed. Competition was modelled using a neighbourhood competition index that considered the effects of inter-and intraspecific competition on target trees. Competitive responses and effects were related to climate.Likelihood methods and information theory were used to select the best model.Results: Our findings revealed that competition had a greater impact on target species growth than tree size or climate. Climate did influence the competitive effects of neighbouring species, but it did not affect the target species? response to competition. The strength of competitive effects varied along the gradient, contingent on the identity of the interacting species. When the target species exhibited an intermediate competitive effect relative to neighbouring species, both higher inter-than intraspecific competitive effects and competition reduction occurred along the gradient. Notably, species competitive effects were most pronounced when the target species' growth was at its peak and weakest when growing conditions were far from their maximum.Conclusions: Climate modulates the effects of competition from neighbouring trees on the target tree and not the susceptibility of the target tree to competition. The modelling approach should be useful in future research to expand our knowledge of how competition modulates forest communities across environmental gradients.

Partial extinction, permanence and global attractivity innonautonomous n-species Lotka-Volterra competitivesystems with impulses

In this paper, the qualitative properties of general nonautonomous Lotka-Volterran-species competitive systems with impulsive e？ects are studied. Some new criteria on thepermanence, extinction and global attractivity of partial species are established by used themethods of inequalities estimate and Liapunov functions. As applications, nonautonomous twospecies Lotka-Volterra systems with impulses are discussed.

Live-streaming selling strategies for competitive firms

The booming live-streaming commerce has significantly changed the traditional e-commerce model,thus attracting much attention from both industry and academia.In recent years,an increasing number of scholars have applied analytical models to explore live-streaming strategies for firms in different scenarios.However,the previous literature mainly considers monopolists,while in the real world,competition is not rare.To fill this gap between the literature and practical observations,this paper applies a game theoretical model to study live-streaming adoption and pricing strategy for firms under competitive environments.The results show that,for competitive firms,the equilibrium strategy depends on the relation between the commission rate and the intensity of the market expansion effect.Additionally,compared to the case in which no firm adopts live-streaming,competitive firms do not always benefit from the adoption of live-streaming selling.The paper also shows that competition plays a negative role in inducing a firm to adopt live-streaming.

Optimal Control for Age Distribution and Weighted Size Competitive Species in a Polluted Environment

In the paper,we study an optimal control for a system representing a competitive species model with fertility and mortality depending on a weighted size in a polluted environment.A fixed point theorem is applied to obtain the existence and uniqueness exhibited by a non-negative solution of above mentioned model.A maximum principle helps to carefully verify the existence of the optimal control policy,and tangent-normal cone techniques help to obtain the optimal condition specific to control issue.

CRB:A new rumor blocking algorithm in online social networks based on competitive spreading model and influence maximization

The virtuality and openness of online social platforms make networks a hotbed for the rapid propagation of various rumors.In order to block the outbreak of rumor,one of the most effective containment measures is spreading positive information to counterbalance the diffusion of rumor.The spreading mechanism of rumors and effective suppression strategies are significant and challenging research issues.Firstly,in order to simulate the dissemination of multiple types of information,we propose a competitive linear threshold model with state transition(CLTST)to describe the spreading process of rumor and anti-rumor in the same network.Subsequently,we put forward a community-based rumor blocking(CRB)algorithm based on influence maximization theory in social networks.Its crucial step is to identify a set of influential seeds that propagate anti-rumor information to other nodes,which includes community detection,selection of candidate anti-rumor seeds and generation of anti-rumor seed set.Under the CLTST model,the CRB algorithm has been compared with six state-of-the-art algorithms on nine online social networks to verify the performance.Experimental results show that the proposed model can better reflect the process of rumor propagation,and review the propagation mechanism of rumor and anti-rumor in online social networks.Moreover,the proposed CRB algorithm has better performance in weakening the rumor dissemination ability,which can select anti-rumor seeds in networks more accurately and achieve better performance in influence spread,sensitivity analysis,seeds distribution and running time.

Construction of CDKN2A-related competitive endogenous RNA network and identification of GAS5 as a prognostic indicator for hepatocellular carcinoma

BACKGROUND Competitive endogenous RNA(ceRNA)is an innovative way of gene expression modulation,which plays a crucial part in neoplasia.However,the intricacy and behavioral characteristics of the ceRNA network in hepatocellular carcinoma(HCC)remain dismal.AIM To establish a cyclin dependent kinase inhibitor 2A(CDKN2A)-related ceRNA network and recognize potential prognostic indicators for HCC.METHODS The mutation landscape of CDKN2A in HCC was first explored using the cBioPortal database.Differential expression analysis was implemented between CDKN2Ahigh and CDKN2Alow expression HCC samples.The targeted microRNAs were predicted by lncBasev3.0,and the targeted mRNAs were predicted by miRDB,and Targetscan database.The univariate and multivariate analysis were utilized to identify independent prognostic indicators.RESULTS CDKN2A was frequently mutated and deleted in HCC.The single-cell RNA-sequencing analysis revealed that CDKN2A participated in cell cycle pathways.The CDKN2A-related ceRNA network-growth arrest specific 5(GAS5)/miR-25-3p/SRY-box transcription factor 11(SOX11)was successfully established.GAS5 was recognized as an independent prognostic biomarker,whose overexpression was correlated with a poor prognosis in HCC patients.The association between GAS5 expression and methylation,immune infilt-ration was explored.Besides,traditional Chinese medicine effective components targeting GAS5 were obtained.CONCLUSION This CDKN2A-related ceRNA network provides innovative insights into the molecular mechanism of HCC formation and progression.Moreover,GAS5 might be a significant prognostic biomarker and therapeutic target in HCC.

A Cooperated Imperialist Competitive Algorithm for Unrelated Parallel Batch Machine Scheduling Problem

This study focuses on the scheduling problem of unrelated parallel batch processing machines(BPM)with release times,a scenario derived from the moulding process in a foundry.In this process,a batch is initially formed,placed in a sandbox,and then the sandbox is positioned on a BPM formoulding.The complexity of the scheduling problem increases due to the consideration of BPM capacity and sandbox volume.To minimize the makespan,a new cooperated imperialist competitive algorithm(CICA)is introduced.In CICA,the number of empires is not a parameter,and four empires aremaintained throughout the search process.Two types of assimilations are achieved:The strongest and weakest empires cooperate in their assimilation,while the remaining two empires,having a close normalization total cost,combine in their assimilation.A new form of imperialist competition is proposed to prevent insufficient competition,and the unique features of the problem are effectively utilized.Computational experiments are conducted across several instances,and a significant amount of experimental results show that the newstrategies of CICAare effective,indicating promising advantages for the considered BPMscheduling problems.

Treatment of Helicobacter pylori with potassium competitive acid blockers:A systematic review and meta-analysis

BACKGROUND Helicobacter pylori(H.pylori)infects over half the global population,causing gastrointestinal diseases like dyspepsia,gastritis,duodenitis,peptic ulcers,GMALT lymphoma,and gastric adenocarcinoma.Eradicating H.pylori is crucial for treating and preventing these conditions.While conventional proton pump inhibitor(PPI)-based triple therapy is effective,there’s growing interest in longer acid suppression therapies.Potassium competitive acid blocker(P-CAB)triple and dual therapy are new regimens for H.pylori eradication.Initially used in Asian populations,vonoprazan(VPZ)has been recently Food and Drug Administration-approved for H.pylori eradication.AIM To assess the efficacy of regimens containing P-CABs in eradicating H.pylori infection.METHODS This study,following PRISMA 2020 guidelines,conducted a systematic review and meta-analysis by searching MEDLINE and Scopus libraries for randomized clinical trials(RCTs)or observational studies with the following command:[("Helicobacter pylori"OR"H pylori")AND("Treatment"OR"Therapy"OR"Eradication")AND("Vonaprazan"OR"Potassium-Competitive Acid Blocker"OR"P-CAB"OR"PCAB"OR"Revaprazan"OR"Linaprazan"OR"Soraprazan"OR"Tegoprazan")].Studies comparing the efficacy of P-CABs-based treatment to classical PPIs in eradicating H.pylori were included.Exclusion criteria included case reports,case series,unpublished trials,or conference abstracts.Data variables encompassed age,diagnosis method,sample sizes,study duration,intervention and control,and H.pylori eradication method were gathered by two independent reviewers.Meta-analysis was performed in R software,and forest plots were generated.RESULTS A total of 256 references were initially retrieved through the search command.Ultimately,fifteen studies(7 RCTs,7 retrospective observational studies,and 1 comparative unique study)were included,comparing P-CAB triple therapy to PPI triple therapy.The intention-to-treat analysis involved 8049 patients,with 4471 in the P-CAB intervention group and 3578 in the PPI control group across these studies.The analysis revealed a significant difference in H.pylori eradication between VPZ triple therapy and PPI triple therapy in both RCTs and observational studies[risk ratio(RR)=1.17,95%confidence interval(CI):1.11-1.22,P<0.0001]and(RR=1.13,95%CI:1.09-1.17,P<0.0001],respectively.However,no significant difference was found between tegoprazan(TPZ)triple therapy and PPI triple therapy in both RCTs and observational studies(RR=1.04,95%CI:0.93-1.16,P=0.5)and(RR=1.03,95%CI:0.97-1.10,P=0.3),respectively.CONCLUSION VPZ-based triple therapy outperformed conventional PPI-based triple therapy in eradicating H.pylori,positioning it as a highly effective first-line regimen.Additionally,TPZ-based triple therapy was non-inferior to classical PPI triple therapy.

Anion competition for Li^(+)solvated coordination environments in poly(1,3 dioxolane)electrolyte to enable high-voltage lithium metal solid-state batteries

Gel-based polymer electrolytes are limited by the polarity of the residual solvent,which restricts the coupling-breaking behaviour during Li^(+)conduction,resulting in the Li^(+)transport kinetics being greatly affected.Here,we designed anion competitive gel polymer electrolyte(ACPE)by introducing lithium difluoro(oxalato)borate(LiDFOB)anion into the 1,3-dioxolane(DOL)in situ polymerisation system.ACPE enhances the ionic dipole interaction between Li^(+)and the solvent molecules and synergizes with Li^(+)across the solvation site of the polymer ethylene oxide(EO)unit,combination that greatly improves the Li^(+)transport efficiency.As a result,ACPE exhibits 1.12 mS cm^(−1)ionic conductivity and 0.75 Li^(+)transfer number at room temperature.Additionally,this intra-polymer solvation sheath allows preferential desolvation of DFOB−,which contributes to the formation of kinetically stable anion-derived interphase and effectively mitigates side reactions.Our results demonstrate that the assembled Li||NCM622 solid-state battery exhibits lifespan of over 300 cycles with average Coulombic efficiency of 98.8%and capacity retention of 80.3%.This study introduces a novel approach for ion migration and interface design,paving the way for high-safety and high-energy-density batteries.

Extensive numerical simulations on competitive growth between the Edwards–Wilkinson and Kardar–Parisi–Zhang universality classes

Extensive numerical simulations and scaling analysis are performed to investigate competitive growth between the linear and nonlinear stochastic dynamic growth systems, which belong to the Edwards–Wilkinson(EW) and Kardar–Parisi–Zhang(KPZ) universality classes, respectively. The linear growth systems include the EW equation and the model of random deposition with surface relaxation(RDSR), the nonlinear growth systems involve the KPZ equation and typical discrete models including ballistic deposition(BD), etching, and restricted solid on solid(RSOS). The scaling exponents are obtained in both the(1 + 1)-and(2 + 1)-dimensional competitive growth with the nonlinear growth probability p and the linear proportion 1-p. Our results show that, when p changes from 0 to 1, there exist non-trivial crossover effects from EW to KPZ universality classes based on different competitive growth rules. Furthermore, the growth rate and the porosity are also estimated within various linear and nonlinear growths of cooperation and competition.

移动环境下具有时滞的 Lotka-Volterra合作模型的行波解

本文研究了移动环境下具有非局部扩散和时滞的Lotka-Volterra合作模型行波解的存在性。 通过构造一对合适的上下解,再利用单调迭代,证明了当环境运动速度时,系统存在行波解。

Enhancement of Competitiveness of Border Trade Entrepreneurs: Case Study of Su-Ngai Kolok Checkpoint, Narathiwat Province

This research aimed to analyze the enhancement of competitiveness among fruit and vegetable export entrepreneurs,with the case study of the Su-ngai Kolok checkpoint in Narathiwat Province.This research focused on three objectives:(1)examining how competitiveness is enhanced through government support and the development of border trade zones,(2)studying the supply chain dynamics,including strategic factors and opportunities in agricultural product management,and(3)developing a model for border trade to strengthen exporters’capabilities.The research employed qualitative methods,with data collected from 25 informants through interviews and employed descriptive methods.The research results revealed that:(1)government agencies play a crucial role in improving competitiveness by developing border economic zones and trade policies;additionally,(2)the research highlighted the importance of strategic partnerships,network building,and efficient logistics along the value chain;(3)the proposed Border Trade Model includes elements for instance government policy,partnerships,entrepreneurial potential,and transportation channels,aiming to enhance the overall efficiency and effectiveness of vegetable and fruit exporters in the region.