نتایج جستجو برای: population equation

تعداد نتایج: 914242  

2012
Tom D. Brewer Joshua E. Cinner Rebecca Fisher Alison Green Shaun K. Wilson

There is overwhelming evidence that many local-scale human activities (e.g. fishing) have a deleterious effect on coral reef fish assemblages. Our understanding of how broad social phenomena (e.g. socioeconomic development) affect the diversity and function of coral reef fish assemblages however, is still poor. Here, we use structural equation models to reveal how human population density, soci...

2004
J. M. Dzakuma E. Risch C. O. Smith H. D. Blackburn

There is a paucity of literature characterizing response to varying levels of feed intake in goats. A controlled experiment was designed at Prairie View A&M University (PVAMU) with purebred goats, to measure feed intake, and its subsequent effects on growth of different goat genotypes when raised intensively. Two goat populations, the Spanish (SP) and the Tennessee Stiff-legged (TS) were fed th...

2006
S. S. Hamed

Spectroscopic diagnostic technique are applied for the determination of excitation temperature Texc and electron density in Air Acetylene premixed laminar flame. A group of FeI spectral lines has been used to estimate Texc using Boltzmann plot. Electron number density was determined from atom ion line pairs for Cd and Zn using Saha Boltzmann equation after substitution the obtained value of exc...

Journal: :Journal of theoretical biology 2006
Harold P de Vladar

The growth function of populations is central in biomathematics. The main dogma is the existence of density-dependence mechanisms, which can be modelled with distinct functional forms that depend on the size of the population. One important class of regulatory functions is the theta-logistic, which generalizes the logistic equation. Using this model as a motivation, this paper introduces a simp...

1996
Esben Sloth Andersen

It is increasingly recognised that population thinking is a basic characteristic of evolutionary economics. By taking its starting point in what is here called Marshall’s fable of the trees, the paper demonstrates that there are several forms of population thinking. The most basic form is intra-population thinking for single populations, and this thinking easily extends to structured population...

2014
Dustin D. Keck David M. Bortz

Abstract. Size-structured population models provide a popular means to mathematically describe phenomena such as bacterial aggregation, schooling fish, and planetesimal evolution. For parameter estimation, generalized sensitivity functions (GSFs) provide a tool that quantifies the impact of data from specific regions of the experimental domain. These functions help identify the most relevant da...

Journal: :Mathematical and Computer Modelling 2012
Donghan Cai

In this paper, a mathematical model is set up to inquire population change under interaction between the economic growth and human population carrying capacity. By introducing the population growth equation with variable carrying capacity into the classical Solow model and combining the population growth equation, we obtain a two-dimensional dynamical system. It is proved that the dynamical sys...

1997
Suzanne M. Lenhart Jiongmin Yong

This paper considers the optimal control of a degenerate parabolic partial differential equation governing a di usive population with logistic growth terms. Assuming this population causes damage to forest and agricultural land, the optimal control is the trapping rate and the cost functional is a combination of the damage and trapping costs. We prove existence, uniqueness, and regularity resul...

2016
John T. Nardini D. M. Bortz

Recent biological research has sought to understand how biochemical signaling pathways, such as the mitogen-activated protein kinase (MAPK) family, influence the migration of a population of cells during wound healing. Fisher’s Equation has been used extensively to model experimental wound healing assays due to its simple nature and known traveling wave solutions. This partial differential equa...

Journal: :SIAM Journal of Applied Mathematics 2013
Pietro Landi Fabio Dercole Sergio Rinaldi

We show in this paper how simulations of ODEs and continuations of systems of algebraic equations can be combined to study the evolution of biodiversity in multi-species systems where phenotypic traits are genetically transmitted. We follow the Adaptive Dynamics (AD) approach, that provides a deterministic approximation of the evolutionary dynamics of stationary coexisting populations in terms ...

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