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 1,027 records · Page 57Linked to original sources
PubMed2003

The evolutionary demography of duplicate genes.

Although gene duplication has generally been viewed as a necessary source of material for the origin of evolutionary novelties, the rates of origin, loss, and preservation of gene duplicates are not well understood. Applying steady-state demographic techniques to the age distributions of duplicate genes censused in seven completely sequenced genomes, we estimate the average rate of duplication of a eukaryotic gene to be on the order of 0.01/ gene/million years, which is of the same order of magnitude as the mutation rate per nucleotide site. However, the average half-life of duplicate genes is relatively small, on the order of 4.0 million years. Significant interspecific variation in these rates appears to be responsible for differences in species-specific genome sizes that arise as a consequence of a quasi-equilibrium birth-death process. Most duplicated genes experience a brief period of relaxed selection early in their history and a minority exhibit the signature of directional selection, but those that survive more than a few million years eventually experience strong purifying selection. Thus, although most theoretical work on the gene-duplication process has focused on issues related to adaptive evolution, the origin of a new function appears to be a very rare fate for a duplicate gene. A more significant role of the duplication process may be the generation of microchromosomal rearrangements through reciprocal silencing of alternative copies, which can lead to the passive origin of post-zygotic reproductive barriers in descendant lineages of incipient species.

Animals↗
PubMed1977

[Demography of several hereditary diseases of the nervous system among the population of the Fergan valley].

The author studied some hereditary diseases of the nervous system among the population of the Fergan Valley. An analysis of 19751 case histories made it possible to estimate the frequency of separate forms of neuroheredodegenerative diseases (Huntington's chorea, Strümpel's paraplegia and different forms of myopathy). A clinico-genetical study of 50 families of the probands permitted to define some clinical and genetical traits of these diseases. It was established that in families of the probands there was a recessive type of inheritance of Strümpel's paraplegia and Erbb's myopathy. Huntington's chorea was characterized by a dominant type of inheritance. It was also established that in famalies with a higher inbreeding, Strümpel's paraplegia was characterized by an early onset of the disease and a rapid development. The author established the frequency of mutations in these diseases which in Hutington's chorea was 2.8X10(-6), for Strümpel's paraplegia--5.8 X 10(-5), Erbb's myopathy 1.12 X 10(5) and Duchenne's myopathy--2.4 X 10(-5).

Adolescent↗
PubMed2001

Modern human origins and prehistoric demography of Europe in light of the present-day genetic diversity.

Dynamic advance in DNA sequencing methods and progress in formal population genetics analyses made it possible to infer aspects of human evolution from the DNA diversity distribution and frequency in contemporary populations. While providing some general background concerning the origins of modern human, this paper focuses on the dynamics of prehistoric population in Europe. The relevance of the present-day genetic diversity studies in elucidating prehistoric events is presented in the context of archeological and paleoanthropological evidence. The questions of the Neanderthal admixture as well as of the relative contribution of different waves of prehistoric migrations to the gene pool of modern Europeans are discussed.

Journal Article↗
PubMed2003

[Demography of nephrologists in France in 2002].

This survey was performed using data generated by a mailing sent with the collaboration of regional coordinators in 2002 to all the nephrologists identified in France. 1326 nephrologists were included in the pool, with an average of 22 nephrologists per million population (pmp), ranging from 14 to 29 pmp according to the different regions. Their mean (and median) age was 46.6 years, 30% were female. 63.5% of the nephrologists were working in a public hospital, 19.3% in private clinics, 13.3% in non-profit associations, 2% and 0.4% in research units or with industry, respectively. The data were used to generate a register of all the French nephrologists. 47 retirements per year are anticipated between 2010 and 2019, which yields an indication for the number of new nephrologists to be certified in this time-span. The gap between the future retirees and the newly trained nephrologists is very deep and cannot be bridged with the currently operating modes of recruitment. The increasing incidence and prevalence of patients with end stage renal failure will considerably increase the need of nephrologists, which is all the more amplified by the recent modification of the French law concerning the weekly upper limit of working time for physicians. Urgent measures have to be taken for preventing the consequences of dearth of nephrologists clearly anticipated for the next 10 years.

Female↗
PubMed2004

>>For better or worse, till death us do part<<--spousal age gap and differential longevity: evidence from historical demography.

Based on a set of 2,371 family related entries dating from 1688 to 1921, the current study tried to verify longevity differentials due to interspousal age difference. For the purpose of the analysis, age-heterogamy was operationalized in terms of sample-specific marital age gap (3.2 years) with a standard deviation of 6.1 years. Based on this, five marriage groups were isolated. Female mean age at marriage experienced a slight increase over time, while the male mean at marriage decreased. This led to an appreciable narrowing of the spousal age gap. Age-homogamous unions were most prevalent in the lower socio-economic class (day-laborers, industrial workers) (p<0.01). In both husband-older and wife-older unions, the interspousal gap increased with marriage order. In accord with previous studies, mean age at death varied significantly by marriage group. Females, who married younger men, died later than females, who married older men. In contrast, male longevity was most depressed within age-similar marriages, while those who married older or younger wives displayed higher life spans. Overall, marriage to a younger spouse seemed to increase longevity prospects (p<0.05). These differentials were not exclusively a function of the marital age gap, but were affected by diverse confounders such as reproductive output and socio-economic status.

Adult↗
PubMed1992

Demography of sexual orientation in adolescents.

This study was undertaken to explore patterns of sexual orientation in a representative sample of Minnesota junior and senior high school students. The sample included 34,706 students (grades 7 through 12) from diverse ethnic, geographic, and socioeconomic strata. Five items pertaining to sexual attraction, fantasy, behavior, and affiliation were embedded in a self-administered survey of adolescent health. Overall, 10.7% of students were "unsure" of their sexual orientation; 88.2% described themselves as predominantly heterosexual; and 1.1% described themselves as bisexual or predominantly homosexual. The reported prevalence of homosexual attractions (4.5%) exceeded homosexual fantasies (2.6%), sexual behavior (1%), or affiliation (0.4%). Gender differences were minor; but responses to individual sexual orientation items varied with age, religiosity, ethnicity, and socioeconomic status. Uncertainty about sexual orientation diminished in successively older age groups, with corresponding increases in heterosexual and homosexual affiliation. The findings suggest an unfolding of sexual identity during adolescence, influenced by sexual experience and demographic factors.

Adolescent↗
PubMedDate not supplied

[Epidemiology and demography of uremia: data from the Lombardy Dialysis and Transplantation Registry (RLDT)].

The Lombardy Registry of Dialysis and Transplantation (RLDT) since 1983 has collected data concerning patients affected by end-stage renal disease (ESRD) on renal replacement therapy (RRT) in Lombardy, a region of Northern Italy with 9 million inhabitants. This report illustrates the main features of ESRD patients on RRT: there were 6589 patients undergoing treatment at 31 December 2003, with a prevalence rate of 727 pmp. Patient numbers regularly increased by 4.5%/yr for the last 5 yrs. This phenomenon is probably due to the high incidence rate (172 pmp) of ESRD patients in Lombardy during these years related to a relatively stable mortality rate (15.2%). The increasing incidence is probably correlated to the population's characteristics: higher rates (189-223 pmp) were observed in certain provinces (Cremona, Lodi and Pavia) with a larger elderly population (people >65 yrs = >20%, people <65 yrs = <16%). Of dialysis modalities, 85% of prevalent patients were on hemodialysis (HD), 55% in hospital, and 30% in limited care units. The number of patients treated by peritoneal dialysis (PD) was stable during the last years, but showed a slow percentage decline (15% during 2003) since 1999. However, PD remains the first dialysis modality for 21.4% of new patients, with a wide variability among renal units. Regarding HD, highly efficient techniques (on-line hemodiafiltration (HDF)) represented 19.2%, with a significant increase (1.8%) compared to 2002. During 2003, the number of dialysis units in Lombardy was stable; there was only an increase in facility beds in limited care units in order to treat the increasing numbers of uremic patients.

Adult↗
PubMed2005

[Impact of canine demography on rabies transmission in N'djamena, Chad].

A transversal study using the clustering technique was carried out in 600 households to estimate dog-population density in the city of N'Djamena and evaluate the knowledge of the inhabitants concerning the risk of rabies. Dog-population density as estimated by negative binomial modelling was 0.03 dogs per person. The dog population estimated taking into account the extrapolated human population for 2001 was at 23 575 dogs (95% confidence interval, 14579-37921 dogs). Three-fourths of inhabitants reported that they had heard of rabies. Most respondents knew some rabies symptoms such as frothing at the mouth, restlessness, and aggressivity. In case of dog-bite injury many respondents said that they would seek care in medical facilities, e.g., health-care centers, hospitals and veterinary clinics, but some said they would also use traditional remedies, witch-doctor services, and self-medication. More than half of the respondents believed that symptomatic rabies could be cured. Because of confinement and feeding needs stray dogs are common. The canine vaccination rate is low (19%) for various reasons including limited financial resources, absence of transportation, unavailability of vaccination facilities, ignorance and negligence. Since access to health care after exposure can be difficult, mass vaccination of dogs is the recommended strategy to control rabies in cities like N'Djamena. Cooperation of all those involved in rabies control is necessary to promote the education and awareness action necessary to promote canine vaccination and reporting of exposure cases to competent authorities.

Animals↗
PubMed2005

Demography, psychosocial factors, and emotional problems of Korean American adolescents.

This study attempted to identify emotional problems and examine the related demographic and psychosocial factors of 340 Korean American adolescents in a major metropolitan area. Results revealed that lower GPA, longer length of residence in the United States, subjects' poor self-esteem, greater severity of conflict with parents, and poor relationships with peers were significant predictors of emotional problems. The findings could be beneficial for social work practitioners and educators in determining the service needs of Korean American adoelscents and designing interventions for their problems.

Acculturation↗
PubMed1992

Demography of the human sex ratio in some Latin American countries, 1967-1986.

A sample based on hospital births recorded for the Latin American Collaborative Study on Congenital Malformations (ECLAMC) program was used in the present study to determine sex ratios for live births and for stillbirths. Sixty-four cities and 147 hospitals in 11 countries (Uruguay, Chile, Argentina, Brazil, Bolivia, Peru, Paraguay, Ecuador, Venezuela, Colombia, and Costa Rica) were included in the present analyses. The number of live births was 1,886,653 in the period 1967-1986, and the number of stillbirths was 24,818 in the period 1978-1986. The sex ratio for the total sample was 0.5112 for live births and 0.5477 for stillbirths. The sex ratio as a whole is decreasing with time in a parabolic fashion. Each country in our study behaved differently. Except for Peru and Uruguay, the countries experienced a significant decrease in the sex ratio after 1978 for live births; only Brazil did not show a temporal trend for the sex ratio for stillbirths.

Birth Rate↗
PubMed2006

Population demography and the evolution of helping behaviors.

Limited dispersal may favor the evolution of helping behaviors between relatives as it increases their relatedness, and it may inhibit such evolution as it increases local competition between these relatives. Here, we explore one way out of this dilemma: if the helping behavior allows groups to expand in size, then the kin-competition pressure opposing its evolution can be greatly reduced. We explore the effects of two kinds of stochasticity allowing for such deme expansion. First, we study the evolution of helping under environmental stochasticity that may induce complete patch extinction. Helping evolves if it results in a decrease in the probability of extinction or if it enhances the rate of patch recolonization through propagules formed by fission of nonextinct groups. This mode of dispersal is indeed commonly found in social species. Second, we consider the evolution of helping in the presence of demographic stochasticity. When fecundity is below its value maximizing deme size (undersaturation), helping evolves, but under stringent conditions unless positive density dependence (Allee effect) interferes with demographic stochasticity. When fecundity is above its value maximizing deme size (oversaturation), helping may also evolve, but only if it reduces negative density-dependent competition.

Altruism↗