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Results for “Population Growth Estimation”

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At least 19 recordsLinked to original sources
PubMed2001

The use of intraallelic variability for testing neutrality and estimating population growth rate.

To better understand the forces affecting individual alleles, we introduce a method for finding the joint distribution of the frequency of a neutral allele and the extent of variability at closely linked marker loci (the intraallelic variability). We model three types of intraallelic variability: (a) the number of nonrecombinants at a linked biallelic marker locus, (b) the length of a conserved haplotype, and (c) the number of mutations at a linked marker locus. If the population growth rate is known, the joint distribution provides the basis for a test of neutrality by testing whether the observed level of intraallelic variability is consistent with the observed allele frequency. If the population growth rate is unknown but neutrality can be assumed, the joint distribution provides the likelihood of the growth rate and leads to a maximum-likelihood estimate. We apply the method to data from published data sets for four loci in humans. We conclude that the Delta32 allele at CCR5 and a disease-associated allele at MLH1 arose recently and have been subject to strong selection. Alleles at PAH appear to be neutral and we estimate the recent growth rate of the European population to be approximately 0.027 per generation with a support interval of (0.017-0.037). Four of the relatively common alleles at CFTR also appear to be neutral but DeltaF508 appears to be significantly advantageous to heterozygous carriers.

Alleles↗
PubMed1985

Density estimation and population growth of mosquitofish (Gambusia affinis) in rice fields.

Mark-release-recapture estimation of population density was performed with mosquitofish in a rice field habitat. Regression analysis showed a relationship between absolute density and mean number of fish per trap. Trap counts were converted to density estimates with data from several fields and growth curves were calculated to describe seasonal growth of mosquitofish populations at three different initial stocking rates. The calculated curves showed a good correspondence to field populations of mosquitofish.

Animals↗
PubMed1998

Maximum likelihood estimation of population growth rates based on the coalescent.

We describe a method for co-estimating 4Nemu (four times the product of effective population size and neutral mutation rate) and population growth rate from sequence samples using Metropolis-Hastings sampling. Population growth (or decline) is assumed to be exponential. The estimates of growth rate are biased upwards, especially when 4Nemu is low; there is also a slight upwards bias in the estimate of 4Nemu itself due to correlation between the parameters. This bias cannot be attributed solely to Metropolis-Hastings sampling but appears to be an inherent property of the estimator and is expected to appear in any approach which estimates growth rate from genealogy structure. Sampling additional unlinked loci is much more effective in reducing the bias than increasing the number or length of sequences from the same locus.

Forecasting↗
PubMed1985

Population trends of Soviet cities, 1970-84.

This article contains a time series for the population of cities of the Soviet Union for the period 1970-1984. The data are from the Soviet censuses of 1970 and 1979 and from official estimates for 1974 and 1984. The article is designed as a continuation of an earlier time series developed by Chauncy D. Harris for the period 1897-1967. "The updated material consists of a series of tables following the patterns of the earlier material, a methodological explanation, and a discussion of significant trends in the population size of Soviet cities."

Demography↗
PubMedDate not supplied

[A method for projecting the population according to size of locality. (Application to the case of Mexico's urban population in 1990)].

"In this article, a restricted components method is presented (because sex and age are not taken into account) to project the population classified according to the size of the locality.... The application is presented for urban centers (15,000 or more inhabitants) of Mexico in 1990, utilizing the trend in demographic growth for the 1960-1980 period." Data are from Mexican censuses conducted in 1960, 1970, and 1980. (SUMMARY IN ENG)

Americas↗
PubMed1979

The urban density function and its application: cross-sectional approach.

Using population census data for the years 1947-1971, the author analyzes the relationship between changes in urban density and population growth in three major coastal urban centers in Queensland, Australia. "Changes in density patterns over time are examined in terms of the empirical exponential density gradient models which emphasise the significance of the distance from the CBD (Central Business District), and a projection of residential population in the centres is made for the year 1990."

Australia↗
PubMed1987

Urbanization and internal migration.

This is a survey of the U.N. Population Division's contributions to the study of urbanization and internal migration, related research, and publications. In order to review these contributions, the relevant U.N. publications are classified under five broad topics: "estimates and projections of urban, rural and city populations, including problems of data comparability and methods to measure internal migration; monitoring of trends in urbanization; estimates and analyses of migration as a component of urban and metropolitan growth; studies of demographic and socio-economic aspects of urbanization, and studies of demographic and socio-economic aspects of internal migration."

Demography↗
PubMedDate not supplied

Loose-coupling a cellular automaton model and GIS: long-term urban growth prediction for San Francisco and Washington/Baltimore.

"Prior research developed a cellular automaton model, that was calibrated by using historical digital maps of urban areas and can be used to predict the future extent of an urban area. The model has now been applied to two rapidly growing, but remarkably different urban areas: the San Francisco Bay region in California and the Washington/Baltimore corridor in the Eastern United States. This paper presents the calibration and prediction results for both regions, reviews their data requirements, compares the differences in the initial configurations and control parameters for the model in the two settings, and discuses the role of GIS in the applications."

Americas↗