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PubMed1990

[Village characteristics and population retention: the case of the Senegal River Valley].

This study is concerned with rural depopulation in Africa and the effectiveness of rural development efforts designed to decrease the outflow of population, using the example of the Senegal River Valley. "On the basis of the results of a study on population mobility of a hundred villages in the region, we analyse the relations between the characteristics of the villages and the retention of their populations. As well, a statistical analysis allows us to question certain assumptions about the capacity of development projects to slow down the population drain from the countryside." Data concern Senegal, Mali, and Mauritania. (SUMMARY IN ENG)

Africa↗
PubMed2004

[Genetic diversity in Tibetan chicken].

Morphological traits and living habit of Tibetan chicken, which is an aboriginal chicken breed on plateau with its own characteristic populational genetic features, are in great common with the Red Jungle Fowl, the assumed ancestry of domestic chicken. To fully exploit this chicken resource, Multiplex PCR with semi-automated polyacrilamide gel electrophoresis (PAGE) using fluorescently labeled microsatellite primers was used to detect the polymorphism at 20 microsatellite loci. At the same time, we randomly test the individual morphology and performance. It showed that numbers of polymorphic alleles were 4 approximately 10, with mean value 7.25 per locus. Polymorphism Information Content (C(PI)) and Heterozygosity (H) had mean values 0.67 and 0.74, respectively. Macrochromosomes had relatively higher polymorphism than microchromosomes(P > 0.05). In all, high polymorphisms at microsatellite loci related to the uneven production performance and morphological discrepancy of population genetic characteristics in Tibetan chicken.

Alleles↗
PubMed1999

The obesity epidemic in children and adults: current evidence and research issues.

PURPOSE: The term "epidemic" of obesity implies that obesity is a characteristic of populations, not only of individuals. The purpose of this paper is to review evidence on obesity in populations and to identify future research issues. METHODS: To examine recent increases in the population prevalence of overweight or obesity, a literature search was undertaken. RESULTS: Trends in overweight or obesity among adults showed considerable variability internationally. Some countries, including Canada, Finland (men), New Zealand, the United Kingdom, the United States, and Western Samoa showed large increases in prevalence (>5 percentage points), whereas several other countries showed smaller or no increases. Overweight is also increasing among children and adolescents, at least in some countries. It is not clear what the expected prevalence of overweight or obesity might be in the current environment, and these findings may be most usefully viewed as shifts in the distribution of a population characteristic. The reasons for these shifts are not clear. The health implications of these shifts are also not clear, in part because trends in cardiovascular risk factors do not always parallel trends in obesity. Of the classic epidemiologic triad of host, agent, and environment, the environment has often received the least attention. CONCLUSIONS: The economic, social, and cultural factors that influence the distribution of body mass index in a population are not well understood. Future research needs include continued monitoring of trends in obesity and in related health conditions and observational studies to examine the causes of these trends. Public health research should aim at defining realistic goals and strategies to improve health in an environment conducive to high levels of overweight and obesity.

Adult↗
PubMed2005

Questionnaire-based risk assessment for amoebic gill disease (AGD) and evaluation of freshwater bathing efficacy of reared Atlantic salmon Salmo salar.

Factors causing amoebic gill disease (AGD), the main disease affecting the salmonid industry in Tasmania, are largely unknown. Managers of 57 sites, from 4 countries, in both the Southern and Northern Hemisphere were questioned regarding the 2000 smolt year-class Atlantic salmon. Questions included site characteristics, fish population characteristics, husbandry and management programs, through to freshwater bathing characteristics. Possible risk factors for AGD outbreaks that were identified in this study using farm managers' opinions were mixed sex stocks (Tasmania), downstream positioning from other salmonid farming sites (pooled), tidal sites (Tasmania), depth of site (pooled), rate of salinity change in halocline and depth of halocline (pooled, Tasmania), phytoplankton blooms (pooled, Tasmania), antifouling paints (Tasmania, overseas) and automated feeding (pooled, overseas). The information from farm managers suggested that freshwater bathing is less effective with smaller bathing cages and lower levels of saturated oxygen in the bathing water. Risk factors could not always be determined due to the complex interactions between the biological and chemical environment, host and pathogenic factors, coupled with low sample numbers.

Analysis of Variance↗
PubMed2002

The spatial dynamics of violence and alcohol outlets.

OBJECTIVE: This study examines whether the association between violence and population density is moderated by the presence of alcohol outlets, both within a target geographical area and in adjacent geographical areas. The effect of sociodemographic variables on violence is also examined controlling for spatial confounding. METHOD: Zip code areas (N = 766) in California from four distinct areas (three urban and one rural) were examined for rates of violence, taking into consideration population characteristics of persons living in those areas and the potential interaction effects of alcohol outlets on violence rates. Population characteristics were assessed using Census data: outlet densities were obtained from the California Department of Alcohol Beverage Control; and violence rates were abstracted from hospital discharge data. A spatial population model of the production of violence was used to examine the relationships of population characteristics of target and surrounding areas to violence rates. RESULTS: The density of bars was found to be strongly associated with greater rates of assault, while density of restaurants was associated with less violence. Both appeared to have greatest effect in densely populated areas. Local and nearby population characteristics were also found to be related to greater rates of violence. CONCLUSIONS: While limited to cross-sectional data, the current study suggests that alcohol outlets, in the presence of socioeconomic measures, moderate the occurrence of violence in urban areas.

Alcoholic Beverages↗
PubMed1998

Left ventricular hypertrophy in northern and Siberian populations.

Characteristics of left ventricular hypertrophy (LVH) were investigated in random samples of the Chukotka coastal Native population (131 males) and in the urban Novosibirsk population (627 males) aged 30-59. Standard epidemiological methods employing electrocardiography (EKG) and echocardiography (EchoCG) were used. The frequency of EKG-LVH in the urban population was about six percent. The prevalence of LVH in Chukotka was more than twice as high as in Novosibirsk, as determined by both EKG and EchoCG criteria. About half of EchoCG-LVH cases in Natives and one-fifth of those in the city population could not be explained by conventional reasons. Advanced family surveys in Novosibirsk established the fact that myocardial hypertrophy exhibits a family aggregation in first-degree relatives of normotensive probands affected by LVH. The data demonstrate an inherited predisposition for LVH and suggest the need for molecular-genetic analysis.

Adult↗
PubMed1999

Osteoblast population migration characteristics on substrates modified with immobilized adhesive peptides.

The process of cell migration is inextricably linked with the process of cell adhesion and, therefore, with cell/substrate adhesiveness. The present study adapted an under-agarose cell migration assay to quantitatively examine population migration characteristics of osteoblasts, on substrates modified with adhesive peptides, in the absence and presence of growth factors. Short-term, that is, 48 h osteoblast migration distances on substrates modified with adhesive Arg-Gly-Asp-Ser peptides were significantly (P < 0.05) less than migration distances on substrates modified with non-adhesive Arg-Asp-Gly-Ser peptides, demonstrating that osteoblast population haptokinesis was significantly decreased on substrates modified with adhesive peptides. Random motility coefficients calculated in the present study for osteoblast populations were an order of magnitude lower than a published random motility coefficient for leukocytes, proving quantitatively that, compared to leukocytes, osteoblasts migrate via haptokinesis more slowly. The 48 and 72 h osteoblast population migration differentials in the presence of an initial mass of 60 ng of basic Fibroblast Growth Factor, on substrates modified with Arg-Gly-Asp-Ser or with Arg-Asp-Gly-Ser, were larger than all other chemotactic differentials on these substrates. Quantitative investigations (such as the present study) of cell population migration characteristics on model biomaterial surfaces will become increasingly necessary as the discipline of cell/tissue engineering matures.

Adhesiveness↗
PubMed1991

Epidemiological correlates of NIDDM in Hispanics, whites, and blacks in the U.S. population.

Characteristics, prevalence, and risk factors for non-insulin-dependent diabetes mellitus (NIDDM) among Hispanics, blacks, and whites aged 20-74 yr in the United States population were investigated with two national surveys that used a household interview to ascertain diagnosed diabetes and a 75-g 2-h oral glucose tolerance test to measure undiagnosed diabetes. The Hispanic Health and Nutrition Examination Survey of 1982-1984 studied Mexican Americans in the southwest U.S., Cuban Americans in the Miami, Florida, area, and Puerto Ricans in the New York City area. The National Health and Nutrition Examination Survey of 1976-1980 examined a national sample of U.S. residents, of whom data on blacks and whites were analyzed. People with diagnosed diabetes in the five populations were similar with respect to mean age (53-57 yr), age at diagnosis (45-48 yr), duration of diabetes (6.9-8.7 yr), and diabetes therapies (58-67% using pharmacological treatment). Mean age of people with undiagnosed diabetes (51-59 yr) was comparable to that of diagnosed cases, and mean fasting (7.1-7.8 mM) and 2-h postchallenge plasma glucose (14.1-15.5 mM) values for people with undiagnosed diabetes were similar among the five populations. However, obesity levels varied by race, sex, and whether diabetes was diagnosed or undiagnosed. Age-standardized prevalence of diabetes (sum of diagnosed and undiagnosed cases) was 6.2% in whites, 9.3% in Cubans, 10.2% in blacks, 13% in Mexican Americans, and 13.4% in Puerto Ricans. Thus, compared to whites, diabetes rates were 50-60% higher among Cubans and blacks and 110-120% higher among Mexican Americans and Puerto Ricans. Age-standardized rates of impaired glucose tolerance were similar among the five populations (10.3-13.8%). Increasing age, obesity, and family history of diabetes were associated with higher rates of diabetes but sex, physical activity, education, income, and acculturation were not risk factors or were only weakly associated with diabetes prevalence.

Adult↗
PubMed2004

[Population development characteristics of rice crop cultivated on aerobic soil with mulching].

Field experiments were carried out to study the population development characteristics of rice crop cultivated both on aerobic and waterlogged soil conditions. The results showed that the whole growth duration of rice growing on aerobic soil was one week longer than that on waterlogged soil. Shorter and narrower leaves and smaller LAI of rice population were found on aerobic soil than on waterlogged soil, which resulted in a decreased photosynthesis, smaller amount and lighter weight of rice grains on aerobic soil, compared with those on waterlogged soil. Among the aerobic treatments, more tillers, lower percentage of filled grains and shorter duration of grain forming were found on soils covered with plastic film than on soils covered with semi-decomposed straw or without mulching. The rice grain yield was decreased in the order of waterlogged soil > aerobic soil covered with plastic film > aerobic soil covered with semi-decomposed straw > aerobic soil without mulching.

Aerobiosis↗
PubMed1993

Demographic characteristics of the population of FR Yugoslavia by nationality.

Changes in the ethnic composition of Yugoslavia as a whole are analyzed using data from censuses carried out between 1948 and 1991. "The subject matter of the analysis [was] the differences in natural movements (birth rate, death rate, natural increase) and migrations by nationalities, as well as marriages and divorces of people of different nationalities." Problems concerning the various ways of identifying ethnic groups by nationality or language are also reviewed.

Culture↗
PubMed1998

Population genetic characteristics of the STR Loci D21S11 and FGA in eight diverse human populations.

A highly polymorphic multiplex short tandem repeat (STR) system composed of D21S11, FGA, and the sex-typing system amelogenin (AMG) has been used to investigate allele frequency distributions in two Canadian Caucasian samples (British Columbia and Alberta), three Canadian aboriginal populations (Coastal Salishans from British Columbia, Ojibwa from northern Ontario, and Cree from Saskatchewan), and three ethnic groups from Singapore (Chinese, Malays, and Asian Indians). Using the automated fluorescence detection approach on an ABD 373A DNA Sequencer, we distinguished 20 D21S11 and 22 FGA alleles with a nearly equal representation of two- and four-base variants. An overlap in allele sizes for both STR loci across populations was observed, but frequency differences were noted. Statistical analysis revealed that (1) both D21S11 and FGA loci conform to Hardy-Weinberg equilibrium in all eight surveyed populations based on five different tests and (2) both STR loci are in linkage equilibrium. Results from the 2 x N contingency table exact tests for population differentiation demonstrated that the Canadian samples from two different provinces were not distinguishable from one another at either STR locus and therefore could be combined to form one Caucasian group. Likewise, Chinese and Malays from Singapore did not show significant differences at either STR locus. In contrast, all other examined populations exhibited differences deemed statistically significant. As a complement to our study, we compared D21S11 allele frequency distributions in 21 worldwide populations and FGA allele frequency distributions in 14 populations. Many alleles never previously reported in worldwide populations were identified in Canadian aboriginal and Asian samples from this study. Twenty-four D21S11 and 29 FGA alleles were distinguished in worldwide groups. Interesting similarities in allele frequency distribution patterns across populations suggest that the STR polymorphism at these loci predates the geographic dispersal of ancestral human populations. This study further demonstrates the utility of highly informative STR loci such as D21S11 and FGA in human population evolutionary history and in forensic medicine.

Canada↗
PubMed2002

Demographic characteristics and population dynamical patterns of solitary birds.

In birds and many other animals, there are large interspecific differences in the magnitude of annual variation in population size. Using time-series data on populations of solitary bird species, we found that fluctuations in population size of solitary birds were affected by the deterministic characteristics of the population dynamics as well as the stochastic factors. In species with highly variable populations, annual variation in recruitment was positively related to the return rate of adults between successive breeding seasons. In stable populations, more recruits were found in years with low return rates of breeding adults. This identifies a gradient, associated with the position of the species along a "slow-fast" continuum of life history variation, from highly variable populations with a recruitment-driven demography to stable, strongly density-regulated populations with a survival-restricted demography. These results suggest that patterns in avian population fluctuations can be predicted from a knowledge of life-history characteristics and/or temporal variation in certain demographic traits.

Animals↗
PubMed2004

Ecological and life history characteristics predict population genetic divergence of two salmonids in the same landscape.

Ecological and life history characteristics such as population size, dispersal pattern, and mating system mediate the influence of genetic drift and gene flow on population subdivision. Bull trout (Salvelinus confluentus) and mountain whitefish (Prosopium williamsoni) differ markedly in spawning location, population size and mating system. Based on these differences, we predicted that bull trout would have reduced genetic variation within and greater differentiation among populations compared with mountain whitefish. To test this hypothesis, we used microsatellite markers to determine patterns of genetic divergence for each species in the Clark Fork River, Montana, USA. As predicted, bull trout had a much greater proportion of genetic variation partitioned among populations than mountain whitefish. Among all sites, FST was seven times greater for bull trout (FST = 0.304 for bull trout, 0.042 for mountain whitefish. After removing genetically differentiated high mountain lake sites for each species FST, was 10 times greater for bull trout (FST = 0.176 for bull trout; FST = 0.018 for mountain whitefish). The same characteristics that affect dispersal patterns in these species also lead to predictions about the amount and scale of adaptive divergence among populations. We provide a theoretical framework that incorporates variation in ecological and life history factors, neutral divergence, and adaptive divergence to interpret how neutral and adaptive divergence might be correlates of ecological and life history factors.

Animals↗
PubMedDate not supplied

Subjective symptomatology of asthma in an outpatient population.

Characteristics of subjective symptomatology of asthma were examined within a group of 132 adult asthma patients receiving medical care in a university-based, ambulatory clinic setting. Patients responded to 36 symptom descriptions or adjectives associated with asthma which were included in a modified version of the Asthma Symptoms Checklist (ASC). A principal components exploratory factor analysis was conducted and five factors were identified. The five factors measured 1) panic-fear, 2) airways obstruction, 3) hyperventilation, 4) fatigue, and 5) irritability. Psychometric properties of the factor scores were satisfactory. The reliabilities were high, standard deviations were large, and differences in factor mean scores conformed to clinical experience. Correlational analyses support the construct validity of the ASC, especially the panic-fear factor. An important outcome of this study was to verify the ASC factor structure in an outpatient setting. The ASC was confirmed as a valuable instrument for use in self-management programs for adults with asthma. The five ASC factors represent highly stable components of subjective symptomatology of asthma among diverse adult patient populations and geographical settings.

Adaptation, Psychological↗
PubMed2005

Osteoporosis in otherwise healthy perimenopausal and early postmenopausal women: physical and biochemical characteristics.

Population studies have shown that about 3-5% of perimenopausal women already have osteoporosis according to the WHO definition of osteoporosis for postmenopausal women ( t -score<or=-2.5). In general, this bone loss arises from well-characterized diseases or conditions that affect acquisition of peak bone mass and/or the rate of bone loss after peak bone mass has been attained. However, there often remains a subset of these women, with no identifiable cause of bone loss. This group has so far been little studied. We prospectively evaluated a group of 60 perimenopausal and early postmenopausal women (mean age 52.2+/-2.5 years) who were found to have apparently unexplained low bone mass, and we compared them to 120 controls matched for age and menopausal status. These women were extensively investigated, including by detailed questionnaire and laboratory testing. Of the 60 women with osteoporosis, only three were found to have previously undiagnosed disorders (two with subclinical hyperthyroidism and one with elevated serum PTH levels) that might have contributed to their low bone mass. On the other hand, osteoporotic patients were characterized by a significantly lower body weight, higher prevalence of personal and parental histories of fractures and a higher level of bone turnover as assessed by increased serum osteocalcin and bone alkaline phosphatase levels and urinary type I collagen C-telopeptide (CTX) excretion, as compared to controls. These findings support theories of a genetic contribution to osteoporosis and underline the predictive value of a previous history of personal and familial fracture in the identification of osteoporosis in early postmenopausal women.

Alkaline Phosphatase↗