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[Survival in colorectal cancers in population statistics].

Available population based survival statistics for colorectal cancers were compared. The results based on relative survival rates showed similar data in Finland, Norway, Geneva and Cote d'Or. The survival rates were lower in Great Britain and Iceland. Several factors complicate survival comparisons: age, exact localization of the tumour, definitions and distribution of tumour stages. Adjustment of these factors is necessary. If their definitions differ, no conclusion can be based upon the data. Population based survival figures provide public health authorities with a basis for monitoring cancer patient care. They are also useful for assessing the resources required for cancer treatment, follow-up and rehabilitation. They provide clinicians with survival data for reference.

Adult

Determination of hprt mutant frequencies in T-lymphocytes from a healthy pediatric population: statistical comparison between newborn, children and adult mutant frequencies, cloning efficiency and age.

Somatic cell mutant frequencies at the hprt locus of the X-chromosome were measured with the T-lymphocyte cloning assay in a healthy pediatric population. Assays were performed on 49 subjects (29 males and 20 females) ranging in age from 0.08 to 15.2 years. A statistical analysis of the thioguanine-resistant (TGr) mutant frequency (MF), unselected cloning efficiency (CE) and age was performed using data obtained in this study and those previously obtained in our laboratory on 66 newborn umbilical cord blood samples and 230 adult blood samples. For statistical comparisons pediatric subjects were divided into 4 groups. Group I included cord blood samples (age 0 years); Group II were subjects between 0 and 5 years; Group III were between 6 and 11 years and Group IV were between 12 and 17 years. The ln MF of Groups I and II were significantly lower than Groups III and IV (p < 0.05). The mean ln MF for each of Groups I-IV was significantly lower than the adult value. The cloning efficiency for Group I was significantly lower than that for Groups II-IV and adults. The relationships among the ln MF, unselected CE and age were expressed by the equations: ln (MF) = 0.945 -2.453 CE (p < 0.001) and ln (MF) = 0.114 + 0.063 age (p 0.004). The slope coefficients for unselected CE and age were significantly different from adults (p < 0.05). Regression analysis of combined data from Groups I-IV and adults were performed using both age and unselected CE as well as terms to reflect differences in their relationships with ln MF in adults and children. The results showed that the intercept and the age coefficients differ significantly for children and adults after adjustment for CE and yielded the following equations: ln (MF) = 0.548 -1.676 CE + 0.075 age, (Groups I-IV) and ln (MF) = 2.263 -1.676 CE + 0.014 age (adults). An alternative statistical model using ln (age ), ln (MF) = 0.381 -1.767 CE + 0.673 ln (age + 1), (p < 0.001), describes the rapid increase in MF with age that levels off in late adolescence. These findings demonstrate the changing influence of age on mutant frequency in the pediatric population as compared to the adult populations. These studies also illustrate that the increase in background somatic mutant frequencies at the hprt locus in T-lymphocytes is not linear from birth to adolescence and is significantly different from that seen in the adult population.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent

The problem of pressure sores in a nursing home population: statistical data.

This study on 93 patients was conducted at a skilled nursing facility. Twenty-two of the 93 patients had pressure sores; 34 of the 54 sores were present when the patients were admitted and 20 developed after admission. Only 5 of the 54 sores healed. Healing times ranged from 15 to 55 days after the beginning of treatment. Thirteen deaths occurred among the 71 patients without sores, and 17 deaths among the 22 patients with sores. Specific treatment regimens varied (cleaning solutions, antimicrobial drugs, heat, enzymatic debridement) but always included frequent changes in the position of the patient. Ten of the 22 patients with sores were anemic vs. 19 of the 71 patients without sores. Half of the patients with sores were maintained with tube feedings whereas more than half of the patients without sores received regular house diets. Pressure sores are a serious problem among geriatric patients in nursing homes. All those who care for the aged should be fully aware of the procedures involved in the prevention and management of these sores.

Adult

1991 Census of Great Britain: summary of results.

All the scheduled Topic Statistics Population Statistics reports from the 1991 Census are now published. This article illustrates the Census range of statistics contained in these reports, making some comparisons with results from the 1981 Census for those topics where there are comparable figures.

Adolescent

[Structural analysis of populations : new statistical approach to the problem of age in Squilla mantis (Crustacea Stomatopoda)].

Thirty-three male length-frequency samples are analysed first by a multivariate procedure. The evolutionary cycles are pointed out by the interpretation of the first two components. The simulation model is built up on the basis of factorial analysis. The assessment of age classes parameters (mean, standard deviation, percentage) is then carried out by the simulation of data. Their configuration with respect to the two components points out the proximity of the observed and generated samples and shows the value of the statistical model.

Age Factors

Using allele frequencies and geographic subdivision to reconstruct gene trees within a species: molecular variance parsimony.

We formalize the use of allele frequency and geographic information for the construction of gene trees at the intraspecific level and extend the concept of evolutionary parsimony to molecular variance parsimony. The central principle is to consider a particular gene tree as a variable to be optimized in the estimation of a given population statistic. We propose three population statistics that are related to variance components and that are explicit functions of phylogenetic information. The methodology is applied in the context of minimum spanning trees (MSTs) and human mitochondrial DNA restriction data, but could be extended to accommodate other tree-making procedures, as well as other data types. We pursue optimal trees by heuristic optimization over a search space of more than 1.29 billion MSTs. This very large number of equally parsimonious trees underlines the lack of resolution of conventional parsimony procedures. This lack of resolution is highlighted by the observation that equally parsimonious trees yield very different estimates of population genetic diversity and genetic structure, as shown by null distributions of the population statistics, obtained by evaluation of 10,000 random MSTs. We propose a non-parametric test for the similarity between any two trees, based on the distribution of a weighted coevolutionary correlation. The ability to test for tree relatedness leads to the definition of a class of solutions instead of a single solution. Members of the class share virtually all of the critical internal structure of the tree but differ in the placement of singleton branch tips.

Alleles

Statistical analysis of population screening.

Statistical techniques used for the evaluation and monitoring of screening tests and screening programmes are reviewed. Though many differences exist between screening to prevent congenital abnormalities, and screening to prevent death from chronic disease, the two are considered together. Analysis for other instances of medical screening will be conceptually similar to one or other of these.

Biometry

Optimal sequential sampling from two populations.

Given two statistical populations with unknown means, we consider the problem of sampling chi 1, chi 2, ... sequentially from these populations so as to achieve the greatest possible expected value of the sum Sn = chi 1 + ... + chi n. In particular, for normal populations, we obtain the optimal rule and study its properties when the average of the two population means is assumed known, and exhibit an asymptotically optimal rule without assuming any prior knowledge about the population means.

Animals