Existence of Four Periodic Solutions of a Ratio-Dependent Predator-Prey Model with Exploited Terms

We study a non-autonomous ratio-dependent predator-prey model with exploited terms. This model is of periodic coefficients, which incorporates the periodicity of the varying environment. By means of the coincidence degree theory, we establish sufficient conditions for the existence of at least four positive periodic solutions of this model.

THE LIMIT CYCLES OF A KIND OF EXPLOITED PREDATOR-PREY SYSTEM

In this paper, a kind of exploited predator-prey system is studied. By using the qualitative theory, we obtain some sufficient conditions for the existence and nonexistence of limit cycles of the system.

Threat Status of Commercially Exploited Trees in the Nigerian Rainforest

Unregulated commercial-scale exploitation of trees is an indication of the extent of threat to various tree species. The study examined the threat status of commercially exploited trees in the forest estates of South eastern Nigeria. Specifically, it identified tree species under threat, and categorized them into threat classes, as well as determined the rate at which exploited trees were slipping into extinction. The study utilized the IUCN’s threat categorization criteria, in determining the threat status of commercially exploited trees. This study combined both secondary and primary data sources generated through Forest Inventory records, Tree Felled Analysis records and Participatory Survey. Data such as population size and density of species, level of exploitation and threat sensitive social and ecological parameters were obtained and applied against the IUCN criteria. Twenty-eight (28) trees species representing Thirty-two percent (32%) of eighty-six (86) commercially exploited trees were identified as threatened, ranging from the Vulnerable to the Critically Endangered categories. The theory of small and declining population paradigms were found to be of relevance in explaining the processes. Nine tree species such as Triplochiton spp., Baillonella toxisperma, Pogaoleosa, Anopyxis spp. among others were considered to require urgent conservation attention. Recommendations are proposed to halt the process of decline in the biodiversity of exploited trees.

Study on optimization of underlying coal bed exploited depth for tunnel

Combined with highway construction, the analysis on the relationship betweentunnel construction and coal resource exploitation was processed, which was based onthe research of rational exploitation depth of coal.3D FEM numerical analysis for tunnelexcavation was carried out according to engineering geological features of coal measurestrata in the project area.Based on the analysis of displacement and stress of the surroundingrock in the tunnel after excavation, the characteristics for displacement andstress of the tunnel support structure were analyzed when the underlying coal bed wasexploited with sublevel and full caving method.In addition, combined with the related codeand standard, the economic and safe prohibiting exploited depth of the underlying coalbed was proposed, so that a scientific basis for tunnel construction of coal measure strataand reasonable exploitation of the mineral resources in complex geological conditions canbe offered.

THE PERSISTENCE OF SOLUTIONS IN A NONLOCAL PREDATOR-PREY SYSTEM WITH A SHIFTING HABITAT

In this paper,we mainly study the propagation properties of a nonlocal dispersal predator-prey system in a shifting environment.It is known that Choi et al.[J Differ Equ,2021,302:807-853]studied the persistence or extinction of the prey and of the predator separately in various moving frames.In particular,they achieved a complete picture in the local diffusion case.However,the question of the persistence of the prey and of the predator in some intermediate moving frames in the nonlocal diffusion case was left open in Choi et al.'s paper.By using some a prior estimates,the Arzelà-Ascoli theorem and a diagonal extraction process,we can extend and improve the main results of Choi et al.to achieve a complete picture in the nonlocal diffusion case.

Coalbed Reserves to be Exploited for New Energy

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Qualitative Properties of Equilibrium Point in a Discrete Predator-Prey Model

In this paper, the dynamic properties of a discrete predator-prey model are discussed. The properties of non-hyperbolic fixed points and hyperbolic fixed points of the model are analyzed. First, by using the classic Shengjin formula, we find the existence conditions for fixed points of the model. Then, by using the qualitative theory of ordinary differential equations and matrix theory we indicate which points are hyperbolic and which are non-hyperbolic and the associated conditions.

Exploitation and Utilization of Insect Protein Feed Resources

The insect is the animal protein feed resource potential, the rapid repro- duction, large quantity, high protein content, and most species of insects can be used as livestock feed utilization, development of insect as feed resources, to pro- mote the development of China＇s animal husbandry and feed industry, has important significance.

基于Predator-Prey行为的双种群粒子群优化算法

根据生物的捕食-食饵(predator-prey)行为的规律,提出了一种双种群粒子群优化(DPPSO)算法.将粒子分成predator和prey两个种群,其中predator种群每间隔一定的迭代次数后排斥prey种群.在排斥的过程中,predator种群采用"擒贼先擒王"的策略,逐步向prey种群的群体最优位置靠近,同时每个prey粒子尽量逃离距离最近的predator粒子.采用了一种速度变异的方法提高prey种群在停滞状态时摆脱局部最优的能力.基准函数的仿真结果表明DPPSO具有速度收敛快和全局搜索能力强的特点.

一类相异功能反应的predator-prey扩散系统的稳定性

针对斑块生境下具有庇护所效应的相异功能性反应predator-prey扩散系统,讨论了系统持续生存的条件.运用常微分方程定性理论讨论了系统解的有界性,通过构造Lyapunov函数得到了一定条件下该系统正解是全局渐近稳定的.进一步利用Pioncare定理和Brower定理证明了惟一周期正解的存在性与稳定性.

Reflection on the Exploitation of Rural Tourism Resources in Zhenjiang City

Rural tourism, i.e., agrotourism, is the newly-exploited tourism product[1] with agricultural production, rustic view, rural life and rural custom as the main carrier and with agriculture and countryside as the tourism resources. Zhenjiang City is in possession of adequate source markets, abundant rural tourism resources, good tourist ecological environment and profound culture. The pleasant ecological environment and charming rural scenery provide the development of rural tourism in Zhenjiang with exceptional advantages. The exploitation of rural tourism not only promotes the exploitation and development of agricultural tourism in Zhenjiang, but also improves the structure of tourism product, simulating the healthy development of rural economy. Through the analysis of the exploitation advantage of the rural tourism resources in Zhenjiang, the author analyzed the exploitation situation and existing problems of the rural tourism resources in Zhenjiang. The author considered that the rural tourism development in Zhenjiang was lack of unified planning; the cultural content of tourism product was low; the development depth was not enough; the construction of infrastructure was lagging behind; and meanwhile, it was lacking of funding, tourism program and advertising promotion. In the light of the above deficiencies, a series of countermeasures of rural tourism exploitation was put forward, that is, to complete the exploitation planning of the rural tourism resources, promoting the cultural taste of the rural tourism product; to enhance the publicity of the rural tourism, highlighting the brand feature of local tourism and creating high-quality product; to conduct standard management, strengthening the training of tourism management personnel.

The Orientation and Development of Zhenjiang Pearl S.Buck Tourism Products Exploitation

This study aimed to make an orientation for the development of Zhenjiang Pearl S.Buck tourism products.According to the spatial structure styles of tourism products,this paper discussed the exploitation of Zhenjiang Pearl S.Buck tourism products from the perspective of spot products,linear products and network products.It expanded the Pearl S.Buck research to tourism science field and put forward some ideas of promoting the comprehensive benefits of Pearl S.Buck tourism resource as well as the exploitation of similar tourism products.

Gradient Differentiation and Exploitation Mode of Tourist Resources in Hailuogou Scenic Area,China

Natural environment of Hailuogou Scenic Area(Conch Gully)was introduced,and it was pointed out that tourist resources in the study area showed gradient differentiation along the vertical height.In view of such gradient differentiation,resource contents and characteristics of its cultural heritages zone,geothermal resources zone,forest vegetation zone,and glacial resources zone were respectively analyzed.Based on the gradient differentiation of tourist resources in Hailuogou Scenic Area,suggestions were given for its further tourism development,and it was stressed that brand effects of the attractions should be enhanced,infrastructure construction and maintenance of newly-explored scenic spots should be improved,and more efforts should be devoted to explore disastrous landform resources.This research is of practical significance for studying spatial differentiation and evolution mechanism of tourist resources in mountainous areas in western China,and also provides scientific support for the exploration of tourist resources in mountainous areas.

Note on a diffusive ratio-dependent predator-prey model

Subject to the homogeneous Neumann boundary condition, a ratio-dependent predator-prey reaction diffusion model is discussed. An improved result for the model is derived, that is, the unique positive constant steady state is the global stability. This is done using the comparison principle and establishing iteration schemes involving positive solutions supremum and infimum. The result indicates that the two species will ultimately distribute homogeneously in space. In fact, the comparison argument and iteration technique to be used in this paper can be applied to some other models. This method deals with the not-existence of a non-constant positive steady state for some reaction diffusion systems, which is rather simple but sufficiently effective.

Exploitation and Sustainable Development of Hot Springs in Xinjiang Province of China——A Case Study of Shawan Hot Spring Tourist Area

The paper had introduced geographic causes and types of hot springs, illustrated its disease-treating function and displayed its great vitality and widespread development prospect as tourist resources. By taking Shawan Hot Spring in Xinjiang for example, the paper had analyzed its natural condition, hot springs and tourist economic development. And then, quantitative and qualitative analysis had been conducted on the quality of water environment resources in the research area. It had analyzed reasons for degeneration of water environment and studied exploitation and sustainable development of hot springs. It was considered that environment especially water environment quality had decreased since hot spring tourism development. In order to achieve sustainable development of hot springs and promotion of local tourism, it must be guided by environment treatment, and some strategies for sustainable development of hot springs had been proposed.

将EXPLOITATION译成“剥削”质疑

英文EXPLOITATION与汉语的"剥削"不能构成互相对译的词汇。EXPLOITATION在英语中的原意是开发、开拓、利用;"剥削"在汉语中解释为"搜刮民财,荼毒天下"。这两个词原始语义不同,词汇的褒贬含义不同,所代表的善恶是非观念界限不同,作为一种社会现象和行为,其合法性和社会后果不同,在未来社会发展进程中的前景和结局不同。当今中国社会所存在的"剥削"是封建社会腐朽的官民关系的残余。EXPLOITATION如果以人为对象客体,则应该译成汉语的"人力资源开发利用"。

EXPLOITATION可以译成“剥削”——与杨彬先生商榷

《将EXPLOITATION译成"剥削"质疑》一文认为把EXPLOITATION一词译成"剥削"是扭曲了词义,应该译成"人力资源开发、利用"。这是不对的。其实,在英语中EXPLOITA-TION有"剥削"之义,可以译成"剥削"。汉语中的"剥削"概念受到了马克思主义政治经济学的影响,但与EXPLOITATION的翻译无关。

Canadian West Exploitation in the Context of American Threat of Annexation

America had been attempting to annex Canadian West and posed a threat to the security of the fledgling country. Therefore the antipathy towards America as well as independent-nation complex of Canadians drove Canadian government to incorporate the west exploitation into the national strategy of creating an independent country. Canadian west exploitation thus took on some distinctiveness.

Windows缓冲区溢出Exploit代码分析研究

该文首先讨论了缓冲区漏洞的产生原理和一般攻击手段,然后分析总结Windows缓冲区溢出漏洞利用的攻击Exploit代码结构和特征,最后讨论了这些特征在入侵检测领域中的应用以及基于系统调用特征的入侵检测这一最新发展方向。