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GLOBAL SOLUTIONS TO A 3D AXISYMMETRIC COMPRESSIBLE NAVIER-STOKES SYSTEM WITH density-dependent VISCOSITY

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Acta Mathematica Scientia 2022年第2期42卷 521-539页

作者： Mei WANG Zilai LI Zhenhua GUO School of Sciences Xi’an University of TechnologyXi’an 710048China School of Mathematics and Information Science Henan Polytechnic UniversityJiaozuo 454000China School of Mathematics and Information Science Guangxi UniversityNanning 530004China

In this paper,we consider the 3D compressible isentropic Navier-Stokes equations when the shear viscosityμis a positive constant and the bulk viscosity is λ(ρ)=ρ^(β) with β>2,which is a situation that was first introduced by Vaigant and Kazhikhov in[1].The global axisymmetric classical solution with arbitrarily large initial data in a periodic domain Ω={(r,z)|r=√x^(2)+y^(2),(x,y,z)∈R^(3),r∈I⊂(0,+∞),-∞density keeps a non-vacuum state ρ>0 when z→±∞.Our results also show that the solution will not develop the vacuum state in any finite time,provided that the initial density is uniformly away from the vacuum.

关键词： Navier-Stokes equations axisymmetric density-dependent classical solution

Illusion of a density-dependent Effect in Biology

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Agricultural Sciences 2015年第5期6卷 479-488页

作者： Kazumi Sakuramoto Department of Ocean Science and Technology Tokyo University of Marine Science and Technology Minato Tokyo Japan

Population changes are believed to be controlled by multiple factors, including an important density-dependent effect. This paper reviews the literature on this topic and shows that this density-dependent effect does not exist. This paper also gives a typical example in which no density-dependent effect was detected in the stock-recruitment relationship in Japanese sardines. The recruitment was found to be determined in proportion to the spawning stock biomass and to be affected by environmental factors. This simple mechanism is applicable not only in fish species but also in insects such as Thrips imaginis in Australia. The reason that many biologists have not become aware that the density-dependent effect does not exist is discussed using a metaphor. This paper proposes a new concept in the study of population change. The new concept proposed here will replace the currently used basic concept that has been assumed to be correct for more than 50 years.

关键词： Arctic Oscillation Index density-dependent Effect Ricker Model Sardine Stock-Recruitment Relationship

1-10 density-dependent Symmetry Energy at Subsaturation Densities

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IMP & HIRFL Annual Report 2014年第1期 14-14页

作者： Fan Xiaohua Dong Jianmin Zuo Wei 不详

The symmetry energy which characterizes the isospin dependence of the equation of state of asymmetric nuclearmatter, plays a crucial role in understanding a variety of issues in nuclear physics and astrophysics, such as heavyion collisions, exotic nuclei, stability of superheavy nuclei, fusion cross sections, the structures, composition andcooling of neutron stars[1??5]. Much theoretical and experimental effort has been made to constrain the densitydependence of symmetry energy. Up to now, we have got some basic knowledge about the symmetry energy at lowdensities, while at high densities we even do not know its variation tendency as a function of density. The problemremains unsolved due to the difficulty of nucleon-nucleon interactions and many-body problems.

关键词： density-dependent Symmetry Energy

Beyond direct neighbourhood effects: higher-order interactions improve modelling and predicting tree survival and growth

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National Science Review 2021年第5期8卷 38-47页

作者： Yuanzhi Li Margaret M.Mayfield Bin Wang Junli Xiao Kamil Kral David Janik Jan Holik Chengjin Chu Department of Ecology State Key Laboratory of BiocontrolSchool of Life SciencesSun Yat-sen University Guangxi Key Laboratory of Plant Conservation and Restoration Ecology in Karst Terrain Guangxi Institute of BotanyGuangxi Zhuang Autonomous Region and Chinese Academy of Sciences Department of Silviculture Faculty of Forestry and Wood TechnologyMendel University in Brno School of Biological Sciences The University of Queensland Department of Forest Ecology Silva Tarouca Research Institute

It is known that biotic interactions are the key to species coexistence and maintenance of species *** studies focus overwhelmingly on pairwise interactions between organisms, ignoring complex higher-order interactions(HOIs). In this study, we present a novel method of calculating individual-level HOIs for trees, and use this method to test the importance of size-and distance-dependent individual-level HOIs to tree performance in a 25-ha temperate forest dynamic plot. We found that full HOI-inclusive models improved our ability to model and predict the survival and growth of trees, providing empirical evidence that HOIs strongly influence tree performance in this temperate forest. Specifically, assessed HOIs mitigate the competitive direct effects of neighbours on survival and growth of focal trees. Our study lays a foundation for future investigations of the prevalence and relative importance of HOIs in global forests and their impact on species diversity.

关键词： pairwise interactions indirect interactions density-dependent size- and distance-dependent Zofin Forest Dynamic Plot

density effect and intraspecific competition in a leaf-mining moth on bamboo leaves

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Journal of Forestry Research 2019年第2期30卷 689-697页

作者： Xiaohua Dai Jiasheng Xu Qingyun Guo Shengchang Lai Peng Liu Juju Fan Peirong Tang Leafminer Group School of Life and Environmental Sciences Gannan Normal University National Navel Orange Engineering Research Center Jiulianshan National Nature Reserve Administration

When confined to a single leaf, the larvae of most leafminers should suffer intense intraspecific competition. The survival and performance of individuals are expected to decline with increasing larval density within a leaf, showing a negative density-dependent effect. The maximum density of an Elachista Treitschke(Lepidoptera:Elachistidae) miner on Indocalamus tessellatus(Munro)Keng f.(Poaceae: Bambusoideae) under natural conditions can be greater than 40 per leaf, making this a good system for studying intraspecific competition and density *** counted the number of leaves with different mine densities in the field and found a clumped distribution of leafminer larvae among host leaves. The emergence rates of pupae(and last-instar larvae), adults and parasitoids were inversely correlated with larval density. Pupal weight and adult weight also showed negative relationships with larval density. However, pairwise tests showed that there might be no differences in pupal or adult weight at larval densities of 1–10 mines per leaf, indicating that densitydependent effects are more obvious at densities greater than 10 mines per leaf. Intraspecific competition could lead to stable density and consistent body size in surviving individual insects, which would help maintain a sustainable population size. The density threshold could be an indicator of the balance between intraspecific competitive detriments and conspecific aggregation benefits; however, the validity of the threshold density hypothesis requires further testing and confirmation.

关键词： Leafminer density-dependent Distribution pattern Sustainable population Threshold density

Exploring the sensitivity of α-decay half-life to neutron skin thickness for nuclei around ^(208)Pb

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Nuclear Science and Techniques 2017年第2期28卷 44-48页

作者： Niu Wan Chang Xu Zhong-Zhou Ren Department of Physics and Key Laboratory of Modern Acoustics Institute of Acoustics Nanjing UniversityNanjing 210093 China Center of Theoretical Nuclear Physics National Laboratory of Heavy-Ion Accelerator Lanzhou 730000 China

Based on the newest experimentally extracted nuclear density distributions for double-magic nucleus208Pb(Tarbert et al. in Phys Rev Lett 112:242502, 2014),the sensitivity of α-decay half-life to nuclear skin thickness is explored in the vicinity of the shell closure region around208 Pb, i.e., isotopes of Z ? 82 and isotones of N ? *** the two-parameter Fermi(2PF) density distributions and an analytically derived formula, the α-decay half-life is found to be closely related to the magnitude of nuclear skin thickness. For a decays to the Z ? 82 isotopes, the α-decay half-life is found to decrease with the increasing neutron skin thickness, while the opposite behavior is found for a decays to the N ? 126 isotones. Therefore, it could be a possible way to extract the nuclear skin thickness from measured α-decay half-lives.

关键词： density distribution Neutron skin thickness density-dependent cluster model a-decay half-life

High nymphal host density and mortality negatively impact parasitoid complex during an insect herbivore outbreak

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Insect Science 2019年第2期26卷 351-365页

作者： Aidan A. G. Hall Scott N. Johnson James M. Cook Markus Riegler Hawkesbury Institute for the Environment Western Sydney University NSW Australia

Insect herbivore outbreaks frequently occur and this may be due to factors that restrict top-down control by parasitoids, for example, host-parasitoid asynchrony, hyperparasitization, resource limitation and climate. Few studies have examined hostparasitoid density relationships during an in sect herbivore outbreak in a n atural ecosystem with diverse parasitoids. We studied parasitization patterns of Cardiaspina psyllids during an outbreak in a Eucalyptus woodland. First, we established the trophic roles of the parasitoids through a species-specific multiplex PCR approach on mummies from which parasitoids emerged. Then, we assessed host-parasitoid density relationships across three spatial scales (leaf, tree and site) over one yeas We detected four endoparasitoid species of the family Encyrtidae (Hymenoptera);two primary parasitoid and one heteronomous hyperparasitoid Psyllaephagus species (the latter with female development as a primary parasitoid and male development as a hyperparasitoid), and the hyperparasitoid Coccidoctonuspsyllae. Parasitoid development was host-synchronized, although synchrony between sites appeared constrained during winter (due to temperature differences). Parasitization was predominantly driven by one primary parasitoid species and was mostly inversely host-density dependent across the spatial scales. Hyperparasitization by C. psyllae was psyllid-density dependent at the site scale, however, this only impacted the rarer primary parasitoid. High larval parasitoid mortality due to density-dependent nymphal psyllid mortality (a consequence of resource limitation) compounded by a summer heat wave was incorporated in the assessment and resulted in density independence of host-parasitoid relationships. As such, high larval parasitoid mortality during insect herbivore outbreaks may contribute to the absence of host density-dependent parasitization during outbreak events.

关键词： density-dependent mortality insect outbreak psyllid synchronization temperature trophic interactions

DYNAMIC BEHAVIOR OF AGE-STRUCTURED RICKER MODEL

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Chinese Science Bulletin 1989年第21期34卷 1811-1814页

作者：刘来福周云 Department of Mathematics Beijing Normal University Beijing 100875 PRC

Let N (t)be the number of individuals in a population at time t. Model I: N (t+1)=λN(t) exp(-βN (t)) describes the dynamics of a density-dependent population for a discrete time, where r=lnλ is the intrinsic growth rate of a population without density dependence, and β measures per capita density sensitivity. Model I is an elementary

关键词： Ricker model density-dependent matrix model bifurcation

Optimal Extraction of Groundwater in Gaza Coastal Aquifer

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Journal of Water Resource and Protection 2009年第4期1卷 249-259页

作者： Khalid QAHMAN Abdelkader LARABI Driss OUAZAR Ahmed NAJI Alexander H.-D. CHENG 不详

Two multi-objective management models are applied on a local area selected from the regional Gaza coastal aquifer. The objectives and constraints of these management scenarios include maximizing the total volume of water pumped, minimizing the salt concentration of the pumped water, and controlling the drawdown limits. The physical model is based on the CODESA-3D density-dependent advective-dispersive solute transport model. Genetic algorithm is used as the optimization tool. The models are tested on a part of the aquifer ( ) with 9 existing pumping wells located at various depths. The results of the optimization show that the optimization/simulation approach can give better decision if there is enough information to feed to the model. It confirms that the use of the concept of safe yield alone is not enough for sustainable develop-ment of the coastal aquifer. It shows that the optimum pumping rate is in the range of 26%–34% of the total natural replenishment. The application shows that the proposed technique is a powerful tool for solving this type of management problems.

关键词： Seawater Intrusion Genetic Algorithm Pumping Optimization density-dependent Miscible Transport