This paper is concerned with the connection between two classes of population variables: measures of population growth rate--the Malthusian parameter, the net reproduction rate, the gross reproduction rate, and the mean life expectancy; and measures of demographic heterogeneity--population entropy. It is shown that the entropy functions predict the response of the growth rate parameters to pert...

biological characteristics and population growth parameters of diaeretiella rapae (hym.: braconidae) on russian wheat aphid, diuraphis noxia (hem.: aphididae) were investigated at five constant temperatures (10, 15, 20, 25 and 27.5 ?c), 60±5% rh and a photoperiodicity of 16:8 h (light:dark). developmental period of immature stages of d. rapae was the lowest at 25 ?c (11.23±0.144 days) and highe...

The intrinsic population growth rate (r) of the surplus production function used in the biomass dynamic model and the steepness (h) of the stock-recruitment relationship used in age-structured population dynamics models are two key parameters in fish stock assessment. There is generally insufficient information in the data to estimate these parameters that thus have to be constrained. We develo...

Structured population models are increasingly used in decision making, but typically have many entries that are unknown or highly uncertain. We present an approach for the systematic analysis of the effect of uncertainties on long-term population growth or decay. Many decisions for threatened and endangered species are made with poor or no information. We can still make decisions under these ci...

Recent research on growth empirics has been focused on resolving model and variable uncertainty. The conventional approach has been to assume a linear growth process and then to proceed with investigating the relevant variables that determine cross-country growth. This paper questions the linearity assumption underlying the vast majority of such research and uses recently-developed nonparametri...

in this study, some of biological parameters of vimba vimba from february 2009 to june 2010 were examined. in total, 281 fish samples were caught by gill- net. in two regions had of five age groups that, the most frequent age groups were related to 2+. sex ratio of male to female were in gorganrud population 67% ? to 33% ? and in mahmoudabad population 57% ? to 43% ? (p?0.05). there was no sign...

Objective: To verify the applicability of standard fetal growth curves proposed for western populations to an Indian population. Method: Thirty patients were included and ultrasound scans were performed on Indian pregnant women to measure fetal growth parameters of biparietal diameter, head circumference, abdominal circumference and femur length for every weekly interval from 14 to 40 weeks. Tw...

Two conceptually different approaches to incorporate growth uncertainty into sizestructured population models have recently been investigated. One entails imposing a probabilistic structure on all the possible growth rates across the entire population, which results in a growth rate distribution model. The other involves formulating growth as a Markov stochastic diffusion process, which leads t...

the present study illustrates the long-term changes in selected socioeconomic variables (population,industrial activities, settlement dispersion, and land-use) together with climate aridity trends in thriasio, the larger industrial area of greece located twenty kilometers far from athens. this region, originally devoted to agriculture, experienced fast industrial and economic development during...