in this study, length-weight relationship of three populations of fingerling roach (rutilus rutilus caspicus), wild, farmed and mix were investigated with the fish reproduce in the center of the proliferation of bony fish syjeval harber. in order to check the length-weight, 587 sample fish by hand sachook during the release into the sea. minimum and maximum total length of respectively 17.14 (f...

We formulate a simple host-parasite type model to study the interaction of certain plants and herbivores. Our two-dimensional discrete-time model utilizes leaf and herbivore biomass as state variables. The parameter space consists of the growth rate of the host population and a parameter describing the damage inflicted by herbivores. We present insightful bifurcation diagrams in that parameter ...

Tumor cell growth models involve high-dimensional parameter spaces that require computationally tractable methods to solve. To address a proposed tumor growth dynamics mathematical model, an instance of the particle swarm optimization method was implemented to speed up the search process in the multi-dimensional parameter space to find optimal parameter values that fit experimental data from mi...

We obtain the exact analytic form of the growth index at present epoch (a = 1) in a flat universe with the cosmological constant (i.e. the dark energy with its equation of state ωde = −1). For the cosmological constant, we obtain the exact value of the current growth index parameter γ = 0.5547, which is very close to the well known value 6/11. We also obtain the exact analytic solution of the g...

Duplication graphs are graphs that grow by duplication of existing vertices, and are important models of biological networks, including protein-protein interaction networks and gene regulatory networks. Three models of graph growth are studied: pure duplication growth, and two two-parameter models in which duplication forms one element of the growth dynamics. A power-law degree distribution is ...

Abstract The Davis Growth Model is a dynamic model used to estimate body composition and growth in beef cattle by simulating total DNA protein turnover. Since development parametrization the 1980s, has been re-structured account for previous rate of accretion prior nutrition. Original parameter estimates alpha (maintenance constant, where net energy maintenance x shrunk weight0.75; 0.08406) K2 ...

A method was developed for estimating parameters in an individual tree basal area growth model using a system of equations based on dbh rank classes. The estimation method developed is a compromise between an individual tree and a stand level basal area growth model that accounts for the correlation between trees within a plot by using seemingly unrelated regression (SUR) to estimate the restri...

A confidence interval is an interval (i.e., a range of values) estimate of a parameter of a population (e.g., a mean) calculated from a sample drawn from the population. A confidence interval has an associated confidence level, which is frequency with which a calculated confidence interval is expected to contain the population parameter. Confidence intervals are of interest in modeling and simu...