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At least 811 records · Page 45Linked to original sources
PubMed1998

Evaluation of genetic variability and genetic distances between eight chicken lines using microsatellite markers.

The genetic variability and divergence of eight chicken lines were evaluated using nine microsatellite markers. The chicken lines included three White Leghorn hybrids, three Finnish Landrace lines, a Rhode Island Red line, and a broiler hybrid line. All the microsatellite loci were found to be polymorphic, the number of alleles varying from 4 to 13 per locus and 1 to 10 per line, respectively. Observed heterozygosities ranged from 0.00 to 0.91. The highest (0.67) and lowest (0.29) mean heterozygosity per line was observed in the broiler and in White Leghorn of Mäkelä, respectively. Three of the microsatellite loci deviated from the Hardy-Weinberg equilibrium in some populations. F statistics indicated clearly the subdivision of the total population into different lines. The genetic distances confirmed the classification of Finnish Landraces into different lines. A phylogenetic consensus tree was constructed from resampled data (1,000 times) using the neighbor-joining method. According to the phylogenetic tree, the lines were grouped into three clusters, in which the White Leghorns formed one group, two Landraces a second group, and a Landrace, the Rhode Island Red, and the broiler lines a third group. Allele distribution at the loci does not support either the stepwise or the infinite alleles mutation model, but the distribution pattern was quite irregular at different loci.

Animals↗
PubMed2000

Symmetries of independent statistical observables for ultrametric populations

When N=2(G), random data X(i), i=1,ellipsis,N show ultrametric covariations, represented by a binary tree, decorrelated observables are defined by a covariance matrix diagonalization. Eigenvalue degeneracies lead one to regroup such observables into eigenprojectors. Symmetries of such projectors are discussed. Such symmetries and degeneracies influence the robustness of the corresponding measurements under random permutations of data.

Journal Article↗
PubMed2006

Scaling relations in food webs.

In the last three decades, researchers have tried to identify universal patterns in the structure of food webs. It was recently proposed that the exponent eta characterizing the efficiency of the transport of energy in large and small food webs might have a universal value (eta = 1.13). In this work we establish lower and upper bounds for this exponent in a general spanning tree with a fixed number of trophic species and levels. When the number of species is large, the lower and upper bounds are equal to 1, implying that the result eta = 1.13 is due to finite-size effects and that the value of this exponent depends on the size of the web. We also evaluate analytically and numerically the exponent eta for hierarchical and random networks. In all cases the exponent eta depends on the number of trophic species K, and when K is large we have that eta-->1. Moreover, this result holds for any fixed number M of trophic levels.

Adaptation, Physiological↗
PubMed1987

Toward a typology of preventively oriented dentists.

This study identifies predictors of preventive behavior among dental general practitioners in New York State. A total of 217 clinicians was interviewed by telephone. Dentists practicing in an urban area (n = 120) and in a rural area (n = 97) were studied. A unit-weighted index of clinician preventive orientation was created, by summing z-score values for two preventive variables: the number of content items and the number of patient visits in an organized preventive program that entailed more than one visit. Multiple regression of this preventive orientation index on selected independent variables showed that, for the entire sample, variables representing involvement in academic and institutional dentistry, exposure to education through journals and courses, a predeliction for innovation, and the presence of a hygienist in the office, were most influential in creating a model that successfully predicted reported preventive behavior. Differences between urban and rural clinicians in predictors of preventive behavior are also identified. Data collected are compared with those of four previous studies that attempted to describe potential predictors of preventive behavior in dentists.

Age Factors↗
PubMed1989

Locational decisions of physicians in rural North Carolina.

Recent literature suggests that there is a rural-urban imbalance of doctors in the United States. In order to investigate this maldistribution, a survey was conducted of 504 physicians in eastern North Carolina. The objective was to determine the factors which most influenced doctors' decisions to locate their practice. A conceptual framework was used to highlight the influence of the community, medical schools and the physician's personal preferences. A discriminant analysis of rural and urban physicians revealed the doctor's personal characteristics to be most important, followed by community and medical school factors. In particular, physicians raised in smaller communities showed a greater preference for practicing in rural areas. Tactics for recruiting rural doctors and other policy recommendations are suggested.

Career Choice↗
PubMed1992

A survey of contraceptive use and unplanned pregnancy in Perth, Western Australia.

Contraceptive use and unplanned pregnancy were studied in a stratified cluster sample of 1,511 couples with women aged 16 to 44 years resident in metropolitan Perth in 1988. Twenty-one couples were excluded from analysis owing to missing data. The proportion of couples using contraception was 76.8 per cent (1,144 of 1,490), and all but three of the remaining couples gave a reason for nonuse. Among users, surgical sterilisation made up 42.3 per cent (484 of 1,144) of all methods, with a slight predominance of tubal ligation over vasectomy. Oral contraceptives accounted for just over half of nonsurgical methods. Comparisons with a Victorian survey performed in 1978 suggested that surgical methods and condom use may have increased, whereas use of oral contraceptives and intrauterine devices may have fallen. Unplanned pregnancies conceived during the 12 months before the interview affected 3.4 per cent (51 of 1,490) of respondents. The incidence of unplanned pregnancy was four times higher in couples with inconsistent usage patterns of contraception.

Adolescent↗
PubMed1994

Subjective assessment of sleep: statistical analysis in a population of healthy subjects.

A principal components analysis was carried out on subjective data obtained from the sleep questionnaire systematically used in our laboratory on the morning following a polysomnographic recording. This technique, based on 70 healthy subjects, revealed three principal axes which explore the questionnaire. The first axis reflects the subjective evaluation of the quality of sleep. The second underlines the importance of dreams and of the brief waking periods which immediately follow. Finally, the third axis brings out the subjective assessment of sleep efficiency. The third axis was the most ambiguous and the only one to show a gender difference. Women tend to better estimate general sleep events, while men tend to evaluate better the more circumstantial events. Finally, given the results, it would be interesting to apply a similar analysis to populations presenting sleep disorders in order to establish the presence of an eventual pattern specific to the disorder.

Adult↗
PubMed2006

Active epilepsy as an index of burden of neurocysticercosis in Vellore district, India.

OBJECTIVE: To determine the contribution of neurocysticercosis (NCC) to the causation of active epilepsy (AE) in a south Indian community. METHODS: We conducted a door-to-door survey of 50,617 people between the ages of 2 and 60 years in a rural (38,105 people) and urban setting (12,512 people) in the Vellore district of the south Indian state of Tamil Nadu to identify patients with AE. Patients with AE were investigated with a contrast-enhanced CT scan and serologic study using enzyme-linked immunotransfer blot (EITB) for cysticercal antibodies. RESULTS: We identified 194 patients with AE. The prevalence of AE was 3.83 per 1,000 people, with the prevalence in the urban clusters more than twice that in the rural clusters (6.23 vs 3.04 per 1,000) (p < 0.0001). A diagnosis of NCC was made in 46 (28.4%) of the 162 patients undergoing a CT scan, and EITB was positive in 21 (13%) patients. Overall, 55 (34%) patients were diagnosed with NCC (11 definitive NCC and 44 probable NCC). There was no significant difference in the prevalence of NCC causing AE in the urban (1.28 per 1,000) and rural (1.02 per 1,000) communities. CONCLUSIONS: NCC is the cause of nearly one-third of all cases of AE in both the urban and rural regions. Extrapolating our results to the country as a whole leads to an estimated disease burden of 1 million patients in India with AE attributable to NCC.

Adolescent↗
PubMed2005

African sequence variation accounts for most of the sequence polymorphism in non-African Drosophila melanogaster.

We compared the sequence polymorphism of 12 genomic fragments in six geographically dispersed African populations to one European Drosophila melanogaster population. On the basis of one African and one European population half of these fragments have strongly reduced levels of variability outside of Africa. Despite this striking difference in European variation, we detected no significant difference in African variation between the two fragment classes. The joint analysis of all African populations indicated that all high-frequency European alleles are of African origin. We observed a negative Tajima's D in all African populations, with three populations deviating significantly from neutral equilibrium. Low, but statistically significant, population differentiation was observed among the African populations. Our results imply that the population structure and demographic past of African D. melanogaster populations need to be considered for the inference of footprints of selection in non-African populations.

Africa↗
PubMedDate not supplied

[The prevalence of viral hepatitis markers in patients hospitalized in infectious disease wards with a diagnosis of acute viral hepatitis].

According with Romanian public health surveillance system, the acute viral hepatitis is nominal reportable disease for what hospital admission is compulsory (Ord. MS 638/1978 and Ord. MS 386/1985); that why, for this condition controlling purpose, only the hospital admitted cases are reported. The acute viral hepatitis statistics do not reflect the morbidity in general population but in hospitalized population; these statistics are very dependent if ill people are hospitalized or not, and in the same time by the lack possibilities of laboratory diagnosis. The objective's study were: a) to describe the structure of laboratory-based diagnostics (using ELISA kits), b) to compare this one with diagnostics established for admitted ill people in infectious wards or clinics, using electroimmunodiffusion (EID) test. The most important findings reveal that from a total of 121 cases about three quarters has been identified as type B viral hepatitis, 20% as type A viral hepatitis and 8.3% were neither type A nor type B viral hepatitis (ELISA kits for hepatitis C diagnosis there was not available for us). According with our findings we think EID technique as etiologic diagnosis for acute viral hepatitis, have to be changed. We need instead a more sensitive and timeliness test; in the same time this has to be permissive from the financial point of view.

Acute Disease↗