Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Population Growth Estimation”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 91 records · Page 5Linked to original sources
PubMed1986

Estimating mortality in skeletal populations: influence of the growth rate on the interpretation of levels and trends during the transition to agriculture.

Traditional paleodemographic methods of estimating mortality have been based on unrealistic assumptions about the prevalence of closed and stationary populations. When a living closed population was growing, the mean age at death of its skeletal survivors will be shifted below its true life expectancy. For declining populations, the mean age at death will be higher than true underlying life expectancy at birth. The faster the rate of growth, the larger and more curvilinear is the displacement. Mortality estimates can only be extracted from skeletal populations via an independent estimate of the growth rate. Fertility levels, however, can be estimated directly. The empirical importance of growth rate-dependent mortality estimates is demonstrated by reinterpreting mean-age-at-death data from several populations before and after the agricultural revolution; with detailed consideration given to the Old World populations of Acsadi and Nemeskeri and a New World population from central Illinois.

Agriculture↗
PubMed1980

[Comparison between the U.N. population projections for Latin America and actual estimates, 1950-1980].

"The purpose of this paper is to compare population projections prepared by the United Nations in the 1950's with the actual estimates for the countries and the regions of Central (including Mexico) and South America. The comparison is made in terms of (a) base population used in the projections (1950), (b) the projected and the estimated population for 1980, and (c) the projected and the estimated rates (including rates of growth) and numbers of births, deaths and migration over the 30 year period of the projections (1950-1980)." (SUMMARY IN ENG)

Developing Countries↗
PubMed2003

Extinction risk to bird populations caused by DDT exposure.

The impact of toxic chemicals on wild animals and plants can be quantified in terms of the enhanced risk of population extinction. To illustrate a method for doing this, we estimated such impact for two bird species: herring gull (Larus argentatus) in Long Island, NY, and sparrowhawk (Accipiter nisus) in eastern England, when they were exposed to DDT (p,p(')-dichlorodiphenyltrichloroethane) and its metabolites (called DDTs). The method we used is based on a formula of the mean time to population extinction derived for a stochastic differential equation (the canonical model). The intrinsic rate of natural population growth was estimated from an exponentially growing population, and the intensity of the environmental fluctuation was estimated from the magnitude of population size fluctuation. The effect of exposure to DDTs in reducing the population growth rate was evaluated based on an age-structured population model, by assuming that age-specific fertility is density-dependent and sensitive to DDTs exposure, but age-specific survivorship is not. The results are expressed in terms of the risk equivalent--the decrease in carrying capacity K that causes the same enhancement of extinction risk as chemical exposure at a given level. The risk equivalent can be used in mitigation banking.

Animals↗
PubMed1992

Urban settlement size trends in the former USSR: 1970-1989.

"Based upon recently published data, this paper investigates urban settlement size trends in the former USSR and its republics during the intercensal periods of 1970-1979 and 1979-1989. Results indicate that although a trend toward largeness of the Soviet urban hierarchy continues, a slowing in this direction has occurred. Among republics, all had an increasing trend towards largeness on at least one and usually all three summary measures of urban settlement size structure. The RSFSR [Russia] and Armenia especially consistently evidenced a relatively high degree of largeness, while the former Baltic republics generally revealed a relative smallness."

Demography↗
PubMed1984

Migration and the growth of metropolitan areas in the third world.

"The purpose of the present paper [is] to investigate further the role of migration in developing countries by analyzing the components of population growth in 26 large metropolitan areas in Africa, Asia, and Latin America." The process of urban population growth is first described. Then, using data from censuses and official U.N. sources, the author examines the relative importance of migration and natural increase in urban growth and in the growth of the largest urban areas. The focus is primarily on the period 1960-1970. Consideration is also given to "estimates of the natural increase of migrants after their arrival in the city in order to assess the full effect of net migration on metropolitan growth, analyses of the relationships between the components of growth and several structural variables and, finally, a discussion of the results." The importance of migration as a factor affecting urban growth is noted.

Demography↗
PubMed2003

Detecting population growth, selection and inherited fertility from haplotypic data in humans.

The frequency of a rare mutant allele and the level of allelic association between this allele and one or several closely linked markers are frequently measured in genetic epidemiology. Both quantities are related to the time elapsed since the appearance of the mutation in the population and the intrinsic growth rate of the mutation (which may be different from the average population growth rate). Here, we develop a method that uses these two kinds of genetic data to perform a joint estimation of the age of the mutation and the minimum growth rate that is compatible with its present frequency. In absence of demographic data, it provides a useful estimate of population growth rate. When such data are available, contrasts among estimates from several loci allow demographic processes, affecting all loci similarly, to be distinguished from selection, affecting loci differently. Testing these estimates on populations for which data are available for several disorders shows good congruence with demographic data in some cases whereas in others higher growth rates are obtained, which may be the result of selection or hidden demographic processes.

Alleles↗
PubMed1992

Fundamental issues in nonlinear urban population dynamic models: theory and a synthesis.

"The main purpose of this paper is to examine certain basic similarities between three nonlinear models of urban dynamics which appeared in [1980], and seem to be driven by somewhat different mechanisms.... By looking at their implicit assumptions we set the stage for addressing certain fundamental premises underlying the process of urban growth or decline. Searching for these fundamental assumptions permits the construction of a comprehensive-unifying theory of urban population dynamics placing urban evolution squarely within the domain of evolutionary theory."

Demography↗
PubMed1977

Nepal: NFP/MCH Project's prime target.

Sterilization as a means of permanent family planning will be the prime target of the Nepal Family Planning and Maternity and Child Health Project in the current fiscal year. Under the permanent sterilization scheme, the project plans to open 18 laparoscopic camps in addition to 34 vasectomy camps in different parts of the country. The 146 mobile teams of the project sent to different parts of the country performed vasectomies on over 9000 males in the previous fiscal year. According to project statistics, more than 38,000 males have undergone vasectomy so far in Nepal. The rate of population growth is estimated to continue to increase by 3% in the next 5 years. This estimate is much higher than the original estimate made during the formation of the current 5-year plan.

Asia↗
PubMed1996

Preliminary evidence for a theory of the fractal city.

"In this paper, we argue that the geometry of urban residential development is fractal. Both the degree to which space is filled and the rate at which it is filled follow scaling laws which imply invariance of function, and self-similarity of urban form across scale. These characteristics are captured in population density functions based on inverse power laws whose parameters are fractal dimensions. First we outline the relevant elements of the theory in terms of scaling relations and then we introduce two methods for estimating fractal dimension based on varying the size of cities and the scale at which their form is detected. Exact and statistical estimation techniques are applied to each method respectively generating dimensions which measure the extent and the rate of space filling. These methods are then applied to residential development patterns in six industrial cities in the northeastern United States...."

Americas↗
PubMed2006

Predator avoidance behavior in the pea aphid: costs, frequency, and population consequences.

Induced prey defenses can be costly. These costs have the potential to reduce prey survival or reproduction and, therefore, prey population growth. I estimated the potential for predators to suppress populations of pea aphids (Acyrthosiphon pisum) in alfalfa fields through the induction of pea aphid predator avoidance behavior. I quantified (1) the period of non-feeding activity that follows a disturbance event, (2) the effect of frequent disturbance on aphid reproduction, and (3) the frequency at which aphids are disturbed by predators. In combination, these three values predict that the disturbances induced by predators can substantially reduce aphid population growth. This result stems from the high frequency of predator-induced disturbance, and the observation that even brief disturbances reduce aphid reproduction. The potential for predators to suppress prey populations through induction of prey defenses may be strongest in systems where (1) predators frequently induce prey defensive responses, and (2) prey defenses incur acute survival or reproductive costs.

Animals↗