نتایج جستجو برای: population dynamics parameters

تعداد نتایج: 1612060  

Journal: :environmental studies of persian gulf 2014
mojtaba pouladi omidvar farhadian vazirizadeh amir

copepods are the main zooplankton assemblages in most tropical and semi-tropical estuaries. in this research, copepod population dynamics were investigated in helleh river estuary, persian gulf during four seasons beginning from summer 2011 to spring 2012.  samples were taken using plankton net with mesh size of 140 µm and vertical towing from 5 fixed-stations in mid-season. results showed that...

2003
Geoff Childs

Despite considerable speculation virtually nothing is known about the empirical relationship between traditional Tibetan administrative systems, household processes, and demographic trends in historical Tibetan populations because indigenous data sources have never been systematically analyzed. This article examines a 1958 tax register from Kyirong, formerly a district-level political division ...

Journal: :bulletin of the iranian mathematical society 2015
l. tan z. hou x. yang

in this paper we use a class of stochastic functional kolmogorov-type model with jumps to describe the evolutions of population dynamics. by constructing a special lyapunov function, we show that the stochastic functional differential equation associated with our model admits a unique global solution in the positive orthant, and, by the exponential martingale inequality with jumps, we dis...

2000
Reginald H. Barrett BARRY R. NOON

Population models have great potential as management tools, as they use information about the life history of a species to summarize estimates of fecundity and survival into a description of population change. Models provide a framework for projecting future populations, determining the effects of management decisions on future population dynamics, evaluating extinction probabilities, and addre...

Journal: :caspian journal of mathematical sciences 2015
m.h. rahmani doust

scientists are interested in find out “how to use living resources without damaging the ecosystem at the same time?” from nineteen century because the living resources are limited. thus, the harvested rate is used as the control parameters. moreover, the study of harvested population dynamics is more realistic.    in the present paper, some predator-prey models in which two ecologically interac...

Journal: :The American naturalist 2007
Nora Underwood

Intrinsic population growth rate and density dependence are fundamental components of population dynamics. Theory suggests that variation in and correlations between these parameters among patches within a population can influence overall population size, but data on the degree of variation and correlation are rare. Replicate populations of a specialist aphid (Chaetosiphon fragaefolii) were fol...

Journal: :Mathematical and Computer Modelling 2008
H. T. Banks John E. Banks Sarah Lynn Joyner John D. Stark

Models of population dynamics play a central role in our understanding of the effects of disturbance in both natural and managed ecosystems. One of the most persistent and pervasive anthropogenic disturbances continues to be the widespread use of chemical pesticides [6]. Because they are ubiquitous and are easy to manipulate in the laboratory and in the field, pesticides are ideally suited for ...

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