Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “DEMOGRAPHY”

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 235 records · Page 13Linked to original sources
PubMed1998

Towards a theory of modern human origins: geography, demography, and diversity in recent human evolution.

The origins of modern humans have been the central debate in palaeoanthropology during the last decade. We examine the problem in the context of the history of anthropology, the accumulating evidence for a recent African origin, and evolutionary mechanisms. Using a historical perspective, we show that the current controversy is a continuation of older conflicts and as such relates to questions of both origins and diversity. However, a better fossil sample, improved dates, and genetic data have introduced new perspectives, and we argue that evolutionary geography, which uses spatial distributions of populations as the basis for integrating contingent, adaptive, and demographic aspects of microevolutionary change, provides an appropriate theoretical framework. Evolutionary geography is used to explore two events: the evolution of the Neanderthal lineage and the relationship between an ancestral bottleneck with the evolution of anatomically modern humans and their diversity. We argue that the Neanderthal and modern lineages share a common ancestor in an African population between 350,000 and 250,000 years ago rather than in the earlier Middle Pleistocene; this ancestral population, which developed mode 3 technology (Levallois/Middle Stone Age), dispersed across Africa and western Eurasia in a warmer period prior to independent evolution towards Neanderthals and modern humans in stage 6. Both lineages would thus share a common large-brained ancestry, a technology, and a history of dispersal. They differ in the conditions under which they subsequently evolved and their ultimate evolutionary fate. Both lineages illustrate the repeated interactions of the glacial cycles, the role of cold-arid periods in producing fragmentation of populations, bottlenecks, and isolation, and the role of warmer periods in producing trans-African dispersals.

Animals↗
PubMed1999

Looking into the demography of an iron age population in the western Mediterranean. I. Mortality.

In this paper, we attempt to reconstruct the mortality pattern of the population buried in S'Illot des Porros (Majorca), an Iron Age necropolis in the western Mediterranean, by means of paleodemographic analysis. The skeletal sample consists of 285 individuals, 93 subadults (under 20 years old) and 192 adults. The aim of this study is twofold: first, to identify and to evaluate the structural anomalies of the skeletal sample, and second, to obtain a possible and realistic description of the biological dynamics of this population, with special reference to its mortality pattern. The study uses current demographic methodology and several demographic models (for comparison). An abridged life table was built to estimate the mortality parameters. To evaluate the likelihood of the estimated data, an indirect analysis, which consisted of a comparison of our results with different population models (Weiss [1973] American Antiquity 38; Coale and Demeny [1996] Regional Model Life Tables and Stable Populations. Princeton: Princeton University Press; Ledermann [1969] Nouvelles tables-types de mortalité. Paris: Presses Universitaires de France), was carried out. An important bias was identified in the case of children, mostly affecting infants but also children between the ages of 1 and 5. This was interpreted as a census error due to taphonomic reasons and to an excluding differential funeral rite. A life expectancy at birth of approximately 28 years was estimated from the observed data. When this bias was removed, the estimated life expectancy at birth dropped to 23 years. The use of the Brass logit system allowed us to sketch a possible mortality profile for this population: low life expectancy, high infant mortality and hard life conditions, which were the cause of the low levels of survivorship in old ages. Am J Phys Anthropol 110:285-301, 1999.

Adolescent↗
PubMed1984

Neural tube defects in Eastern Ontario and Western Quebec: demography and family data.

This paper reports the results of a study of families in the Eastern Ontario/Western Quebec region who had a child born with a neural tube defect during the years 1969-1981. As in several other geographic areas, the prevalence of neural tube defects at birth has fallen from previous levels. However, there was no evidence of further decline during the period of study. Socioeconomic and ethnic influences were noted, but there was no evidence of seasonal variation or any correlation with maternal age or parity. There was support for a causative role of maternal fever in some cases. The rates of miscarriage varied between pregnancies before and those after the proband, and there was an excess of males born prior to the proband. Family studies showed a 2.4% risk for sibs born after the proband and an excess of affected relatives on the maternal side. Knowledge of rates of occurrence in relatives is useful for counseling and the interpretation of the results of alpha-fetoprotein screening.

Abortion, Spontaneous↗
PubMed2001

Demography and pedigree structure of an SPF colony of rhesus monkeys (Macaca mulatta).

The SPF rhesus colony at the M.D. Anderson Cancer Center in Bastrop, Texas, was analyzed with the aim of determining the demographic and genetic effects of stringent selection for virus-free breeders, permanent quarantine, continued surveillance, and culling of animals that show evidence of viral infection. The analysis shows minimal effects on population viability and loss of genetic variability in comparison with the traditionally managed (non-SPF) portion of the population.

Animal Husbandry↗
PubMed2007

Demography and life history of Thomas langurs (Presbytis thomasi).

Life history data from wild primate populations are necessary to explain variation in primate social systems and explain differences between primates and other mammals. Here we report life history data from a 12.5-year study on wild Thomas langurs. Mean age at first reproduction was 5.4 years and the sex ratio at birth was even. The mean interbirth interval (IBI) after a surviving infant was 26.8 mo, after nonsurviving infants 17.7 mo, and combined 22.0 mo. Mean annual birth rate of adult females was 0.44, while reaching a peak at 6 years of age and showing no decrease with age. Mortality was highest during the first year of life (48.0% for males and 43.0% for females) and consistently higher for males than females. The oldest female observed during the study was estimated to be 20 years of age, whereas the oldest male disappeared at age 13 years, indicating that males die at a much earlier age than females. A Leslie matrix based on these estimates yielded a growth rate of 1.01, which is comparable to the nonsignificant increase in density indicated by our long-term field data. A comparison with life history data for sympatric frugivorous primates suggests that folivory might be associated with faster life history.

Age Factors↗