[Study of the body composition by isotopic dissection. II. Statistical study of the relations among the diverse measured values].
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Body Composition↗
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On the explanation of the changes in age of the concentration of the death causes.
The high concentration of the diagnoses among the categories of death causes is called the concentration of death causes. The idea of diversity used in statistical ecology is in a sense a contrary concept. Introducing the investigation of diversity indices on epidemiological material, we have shown sexual differences and age characteristics of the latter. In the course of the investigations, there was an opportunity to measure exactly and analyse the high increase of the concentration of death causes at an older age. In this paper we related the changes due to age to the structure of the set of specific death rates and to that of hazard functions. According to our fitting investigations, the majority of the elements of the set of curves could be well approximated by the Gompertz or by the Weibull function. In this case, a mathematical explanation can be given to the increase, then decrease of Hill's diversity indices, that is, to the decrease, than increase of the concentration of death causes. Finally we point briefly to the evolutionary aspects of the discussed changes with age of this concentration.
Adult↗
[Estimation of diversity by morphological markers].
A genetic statistical method for estimation of intraspecific diversity of cultivated plants with respect to morphological genes is proposed. The method may be used for estimation of probability distributions of morphological (marker) mutations with respect to the frequencies of their expression and for prediction of experimental parameter such as the total number of markers, the scale (duration) of the experiment that is necessary for detection of a given proportion of the total marker diversity of the species, etc. The method was tested on tomato Lycopersicon esculentum Mill. using data from the SolGenes Internet databank.
Biomarkers↗
Analysis of DNA diversity by spatial autocorrelation.
Two statistics are proposed for summarizing spatial patterns of DNA diversity. These autocorrelation indices for DNA analysis, or AIDAs, can be applied to RFLP and sequence data; the resulting set of autocorrelation coefficients, or correlogram, measures whether, and to what extent, individual DNA sequences or haplotypes resemble the haplotypes sampled at arbitrarily chosen spatial distances. Analyses of computer-generated sets of data, and of RFLP data from two natural populations, show that AIDAs allow one to objectively and simply identify basic patterns in the spatial distribution of haplotypes. These statistics, therefore, seem to be a useful tool both to explore the genetic structure of a population and to suggest hypotheses on the evolutionary processes that shaped the observed patterns.
DNA↗
Polymerase chain reaction denaturing gradient gel electrophoresis analysis of the N2-fixing bacterial diversity in soil under Acacia tortilis ssp. raddiana and Balanites aegyptiaca in the dryland part of Senegal.
Denaturing gradient gel electrophoresis (DGGE) of amplified nifH gene fragments was used to study the diazotrophic community of soil samples under Acacia tortilis ssp. raddiana (legume tree) and Balanites aegyptiaca (non-legume tree), two dominant plant species growing naturally in the dryland part of Senegal. Samples were taken along transects from the stem up to 10 m distance from it, at depths of 0-0.25 m and 0.25-0.50 m. Sampling was done in the dry season (25 June 1999) and in the rainy season (28 August 1999). The community structure and diversity of the bacterial groups from the different samples was analysed further using different techniques, such as statistical analysis and diversity index evaluation of the band patterns. Diazotrophic diversity was lower under B. aegyptiaca than under A. tortilis ssp. raddiana. Multidimensional scaling (MDS) analysis and ANOSIM tests showed a significant effect of the tree on the diazotroph assemblages. SIMPER analysis showed that the major elements responsible for the dissimilarity are a member of the genus Sinorhizobium, which is characteristic of the samples taken under A. tortilis ssp. raddiana and a member of the cluster Bradyrhizobium for the samples taken under B. aegyptiaca. Forty-four major bands were partially sequenced, yielding 33 different nifH sequences, which were used in phylogenetic reconstructions. Most sequences were affiliated with the alpha- beta- and gamma-proteobacteria. Five nifH sequences were identical to those of Pseudomonas stutzeri, and one sequence showed 100% similarity to that of Azotobacter vinelandii. Four bands were affiliated with the Cyanobacteria and a single one with the Firmicutes. For both trees, there were also clear differences between the samples taken in the dry and rainy seasons. Only for the samples taken under A. tortilis ssp. raddiana was a significant difference found between the two sampling depths.
Acacia↗
[Dietary diversity and associated factors among beneficiaries of 77 child care centers: Central Regional, Venezuela].
The aim of this study was to estimate household measure diet quality, using a dietary diversity score, and its associated demographic and socio-economic factors. One hundred fifty three households representatives of the Capital District and Miranda State belonging of seventy seven day care children centers were studied. To gather data on dietary diversity, we used the food register method, collecting data on household food availability during a month. Dietary diversity at day care centers of the Capital District was 46 foods differed from that found, in Miranda State was 39 foods (p = 0.005). Likewise it differed in beneficiaries' households of the Capital District was 33 foods compared to those in Miranda State was 25 foods (p = 0.000). There were 13 and 14 foods more between day care centers and the households in both states. State (Capital District or Miranda), money spent on food per person, households size and social level were variables that explained 28.9% of dietary diversity variation in households studied. Households in the Capital District had less members, spent more money on food, and a greater proportion were non-poor compared to those in Miranda. These factors could partially explain differences in diet quality among households in the two States. Whatever perspective studied indicates that the dietary diversity had a statistically significant difference between day care centers and households in states studied. Miranda State was more deficiency than Capital District. Higher dietary diversity reflects a better quality diet at day care centers compared to households studied.
Child↗
LORETA imaging of P300 in schizophrenia with individual MRI and 128-channel EEG.
We investigated the characteristics of P300 generators in schizophrenics by using voxel-based statistical parametric mapping of current density images. P300 generators, produced by a rare target tone of 1500 Hz (15%) under a frequent nontarget tone of 1000 Hz (85%), were measured in 20 right-handed schizophrenics and 21 controls. Low-resolution electromagnetic tomography (LORETA), using a realistic head model of the boundary element method based on individual MRI, was applied to the 128-channel EEG. Three-dimensional current density images were reconstructed from the LORETA intensity maps that covered the whole cortical gray matter. Spatial normalization and intensity normalization of the smoothed current density images were used to reduce anatomical variance and subject-specific global activity and statistical parametric mapping (SPM) was applied for the statistical analysis. We found that the sources of P300 were consistently localized at the left superior parietal area in normal subjects, while those of schizophrenics were diversely distributed. Upon statistical comparison, schizophrenics, with globally reduced current densities, showed a significant P300 current density reduction in the left medial temporal area and in the left inferior parietal area, while both left prefrontal and right orbitofrontal areas were relatively activated. The left parietotemporal area was found to correlate negatively with Positive and Negative Syndrome Scale total scores of schizophrenic patients. In conclusion, the reduced and increased areas of current density in schizophrenic patients suggest that the medial temporal and frontal areas contribute to the pathophysiology of schizophrenia, the frontotemporal circuitry abnormality.
Adolescent↗
Coastal Environmental Impacts Brought About by Alterations to Freshwater Flow in the Gulf of Mexico
/ Freshwater inflow is one of the most influential landscape processes affecting community structure and function in lagoons, estuaries, and deltas of the world; nevertheless there are few reviews of coastal impacts associated with altered freshwater inputs. A conceptual model of the possible influences of freshwater inflows on biogeochemical and trophic interactions was used to structure this review, evaluate dominant effects, and discuss tools for coastal management. Studies in the Gulf of Mexico were used to exemplify problems commonly encountered by coastal zone managers and scientists around the world. Landscape alteration, impacting the timing and volume of freshwater inflow, was found to be the most common stress on estuarine systems. Poorly planned upstream landscape alterations can impact wetland and open-water salinity patterns, nutrients, sediment fertility, bottom topography, dissolved oxygen, and concentrations of xenobiotics. These, in turn, influence productivity, structure, and behavior of coastal plant and animal populations. Common biogeochemical impacts include excessive stratification, eutrophication, sediment deprivation, hypoxia, and contamination. Common biological impacts include reduction in livable habitats, promotion of "exotic" species, and decreased diversity. New multiobjective statistical models and dynamic landscape simulations, used to conduct policy-relevant experiments and integrate a wide variety of coastal data for freshwater inflow management, assume that optimum estuarine productivity and diversity is found somewhere between the stress associated with altered freshwater flow and the subsidy associated with natural flow. These models attempt to maximize the area of spatial overlap where favorable dynamic substrates, such as salinity, coincide with favorable fixed substrates, such as bottom topography. Based upon this principle of spatial overlap, a statistical performance model demonstrates how population vitality measurements (growth, survival, and reproduction) can be used to define sediment, freshwater, and nutrient loading limits. Similarly, a spatially articulate landscape simulation model demonstrates how cumulative impacts and ecosystem processes can be predicted as a function of changes in freshwater, sediment, and nutrient inflows.KEY WORDS: Resource management; Landscape impacts; Freshwater discharge; Coastal, ecosystem models; Coastal wetlands
Journal Article↗
When should quality of life be measured after radical cystectomy?
AIM: In this prospective study our aim was to establish the time it takes cystectomized patients' to adapt to their new health status. MATERIALS AND METHOD: A total of 68 patients, having radical cystectomy for bladder cancer (64 males and 4 females) were enrolled in the study. The mean age of the group was 55.4 +/- 8.0 years (range 38-70 years). Continent urinary diversion was applied to 17 while the rest had incontinent urinary diversions. There was no statistical difference between those who had continent and incontinent diversions in regard to pre-operative stage. All patients were given a Beck's Depression Inventory (BDI), an EORTC-QLQ C-30 Version 2 (European Organization for Research on Treatment of Cancer Quality of Life Questionnaire C-30 Version 2) quality of life measurement scale pre-operatively, and post-operatively 3, 6, 12 and >12 months (every 6 months). Log-rank and Student's t-test was used for statistical analysis of the results. RESULTS: The mean follow-up of the study group was 27.7 +/- 7.3 months (range 12-46 months). Five patients at the first 3rd-month control, seven at the 6th-month control and eight at the 12th-month control did not appear for interview, but their available results were also included in the overall assessment. The mean functional score of the study group, evaluated by QLQ C-30, was 80 +/- 25.4 pre-operatively. There is dramatic decrease at the 3rd-month control (56.9 +/- 25.1; p < 0.01). The overall functional score after 12 months (80 +/- 20) is back to the pre-operative value. The mean symptom score of the group pre-operatively was 29.5 +/- 16.7, which showed similar results at 3 and 6 months post-operatively of 29.8 +/- 16.7 and 30.6 +/- 19.4, respectively (p > 0.05). At the 12th-month and thereafter the symptom scores of the patients decreased significantly in comparison to both the pre-operative and the post-operative 3-6 months (23.4 +/- 13.7 and 21.8 +/- 18.5, respectively; p < 0.01 for all). The self-rating general health status of this group was lowest pre-operatively with a mean of 49.8 +/- 26.5. Interestingly, there was a statistically significant increase in the general health status assessment of the patients even at the early post-operative period of 3 months (61.4 +/- 17.2; p < 0.01). The increase in the well-being of the patients increased linearly until the 12th-month control and stabilized thereafter. There was a 23% pre-operative depression rate, which comes down to 16% at the 12th-month control. The peak depression scores suggesting depression are observed at the 3rd-month controls. There is a gradual decrease in depression score starting from the 6th-month controls and all reach minimum scores after 12 months. Ninety-six percent of the study group showed scores even lower than the pre-operative ones. The mean pre-operative and post-operative 12th-month control scores were 11.5 +/- 7.7, and 8.1 +/- 6.8, respectively (p < 0.01). CONCLUSION: Both psychological and health-related quality of life measures come to baseline values and stabilize after the 12th-month period, suggesting that the time frame for the adaptation of patients is 12 months in patients undergoing radical cystectomy surgery. Therefore, we believe it is better to perform any quality of life assessment as an end-point criterion for comparison of treatment modalities in radical cystectomy patients after 12 months.
Activities of Daily Living↗
Genetic composition of Jewish populations: diversity and inbreeding.
Genetic diversity and F statistics analysis, using 9 and 5 blood group loci, respectively, were carried out on 16 Jewish populations from 5 geographic regions: East Europe, Central Europe, South Europe, Middle East and North Africa. The proportion of total diversity found within populations was 98.9% while that between populations, within geographic groups and between groups altogether was only 1.1%. The average heterozygosity between geographic groups ranged from 0.3867 to 0.4150. There were no significant differences between geographic groups of populations in heterozygosity or in its variance. Average estimates of inbreeding were as follows: Fis = 0.0419, Fst = 0.0084 and Fit = 0.0498. Because the heterogeneity and relative proportion of diversity were less between Jewish populations than between non-Jewish ones, we conclude that genetic similarity between Jews is higher than between Gentiles. The findings are in agreement with our previously obtained calculations of genetic distances (Kobyliansky, Micle, Goldschmidt-Nathan, Arensburg and Nathan 1982).
Africa, Northern↗
Recurrent gene amplification and soft selective sweeps during evolution of multidrug resistance in malaria parasites.
When selection is strong and beneficial alleles have a single origin, local reductions in genetic diversity are expected. However, when beneficial alleles have multiple origins or were segregating in the population prior to a change in selection regime, the impact on genetic diversity may be less clear. We describe an example of such a "soft" selective sweep in the malaria parasite Plasmodium falciparum that involves adaptive genome rearrangements. Amplification in copy number of genome regions containing the pfmdr1 gene on chromosome 5 confer resistance to mefloquine and spread rapidly in the 1990s. Using flanking microsatellite data and real-time polymerase chain reaction determination of copy number, we show that 5-15 independent amplification events have occurred in parasites on the Thailand/Burma border. The amplified genome regions (amplicons) range in size from 14.7 to 49 kb and contain 2-11 genes, with 2-4 copies arranged in tandem. To examine the impact of drug selection on flanking variation, we genotyped 48 microsatellites on chromosome 5 in 326 parasites from a single Thai location. Diversity was reduced in a 170- to 250-kb (10-15 cM) region of chromosomes containing multiple copies of pfmdr1, consistent with hitchhiking resulting from the rapid recent spread of selected chromosomes. However, diversity immediately flanking pfmdr1 is reduced by only 42% on chromosomes bearing multiple amplicons relative to chromosomes carrying a single copy. We highlight 2 features of these results: 1) All amplicon break points occur in monomeric A/T tracts (9-45 bp). Given the abundance of these tracts in P. falciparum, we expect that duplications will occur frequently at multiple genomic locations and have been underestimated as drivers of phenotypic evolution in this pathogen. 2) The signature left by the spread of amplified genome segments is broad, but results in only limited reduction in diversity. If such "soft" sweeps are common in nature, statistical methods based on diversity reduction may be inefficient at detecting evidence for selection in genome-wide marker screens. This may be particularly likely when mutation rate is high, as appears to be the case for gene duplications, and in pathogen populations where effective population sizes are typically very large.
ATP-Binding Cassette Transporters↗
Sparse Bayesian kernel survival analysis for modeling the growth domain of microbial pathogens.
Survival analysis is a branch of statistics concerned with the time elapsing before "failure," with diverse applications in medical statistics and the analysis of the reliability of electrical or mechanical components. We introduce a parametric accelerated life survival analysis model based on kernel learning methods that, at least in principal, is able to learn arbitrary dependencies between a vector of explanatory variables and the scale of the distribution of survival times. The proposed kernel survival analysis method is then used to model the growth domain of Clostridium botulinum, the food processing and storage conditions permitting the growth of this foodborne microbial pathogen, leading to the production of the neurotoxin responsible for botulism. A Bayesian training procedure, based on the evidence framework, is used for model selection and to provide a credible interval on model predictions. The kernel survival analysis models are found to be more accurate than models based on more traditional survival analysis techniques but also suggest a risk assessment of the foodborne botulism hazard would benefit from the collection of additional data.
Artificial Intelligence↗
Career path to CFO: selection, training, and placement.
Not long ago, chief financial officers (CFOs) in hospitals could focus almost exclusively on financial accounting. Today, however, financial managers must tend diverse tasks of coordination, education, and professional specialization. The authors suggest that those who desire the position of CFO would do well to couple accounting expertise with a capacity to understand ethics and mores, economics, descriptive and predictive statistics, people from diverse socioeconomic and cultural backgrounds, as well as features of disease, its prevention, and course of treatment.
Career Mobility↗
Positive selection on a human-specific transcription factor binding site regulating IL4 expression.
A single nucleotide polymorphism in the promoter of the multifunctional cytokine Interleukin 4 (IL4) affects the binding of NFAT, a key transcriptional activator of IL4 in T cells. This regulatory polymorphism influences the balance of cytokine signaling in the immune system, with important consequences-positive and negative-for human health. We determined that the NFAT binding site is unique to humans; it arose by point mutation along the lineage separating humans from other great apes. We show that its frequency distribution among human subpopulations has been shaped by the balance of selective forces on IL4's diverse roles. New statistical approaches, based on parametric and nonparametric comparisons to neutral variants typed in the same individuals, indicate that differentiation among subpopulations at the IL4 promoter polymorphism is too great to be attributed to neutral drift. The allele frequencies of this binding site represent local adaptation to diverse pathogenic challenges; disease states associated with the common derived allele are side-effects of positive selection on other IL4 functions.
Animals↗
Microbial diversity in hypersaline wastewater: the example of tanneries.
In contrast to conventional wastewater treatment plants and saline environments, little is known regarding the microbial diversity of hypersaline wastewater. In this study, the microbial communities of a hypersaline tannery effluent, and those of three treatment systems operating with the tannery effluent, were investigated using 16S rDNA phylogenetic markers. The comparative analysis of 377 bacterial sequences revealed the high diversity of this type of hypersaline environment, clustering within 193 phylotypes (> or = 97% similarity) and covering 14 of the 52 divisions of the bacterial domain, i.e. Proteobacteria, Bacteroidetes, Firmicutes, Actinobacteria, Chlorobi, Planctomycetes, Spirochaetes, Synergistes, Chloroflexi, Thermotogae, Verrucomicrobia, OP3, OP11 and TM7. Most of the phylotypes were related to halophilic and pollutant-degrading bacteria. Using statistical analysis, the diversity of this type of environment was compared to that of other environmental samples selected on the basis of their salinity, oxygen content and organic load.
Bacteria↗
Morphometry of the midfacial complex in subjects with class III malocclusions: Procrustes, Euclidean, and cephalometric analyses.
The purpose of this study was to determine whether the morphology of the midface differed in subjects with a retrognathic midfacial appearance (Class III malocclusions) using a combination of morphometric and cephalometric analyses. After obtaining appropriate consent, lateral cephalographs of 133 children of European-American descent, ages 5-11 years, were compared: 73 had Class III malocclusion, 60 had normal (Class I) occlusion. The cephalographs were traced and subdivided into seven age- and sex-matched groups. Average geometries based upon seven nodes (pterygoid point, PTS; rhinion, RO; posterior nasal spine, PNS; midpalatal point, MPP; anterior nasal spine, ANS; subspinale, A; prosthion, Pr), scaled to an equivalent size, were compared using a Procrustes routine. Euclidean distance matrix analysis (EDMA) was employed to localize differences in morphology. Bivariate analyses on unscaled data utilizing nine linear and six angular measurements were also undertaken. Results from Procrustes and EDMA analyses indicated that although the overall midfacial configurations differed statistically (P < 0.05), only about half of the seven age sub-groups maintained significance. Similarly, only four of the nine linear measures (PNS-MPP, MPP-ANS, A-Pr and PTS-RO) and two of the six angular parameters (PTS-RO-ANS and ANS-A-Pr) tested were significantly different (P < 0.05). Therefore, midfacial morphometric variability and morphological diversity may mask statistical differences. It is concluded that the midface may be the defining craniofacial component in the final appearance of Class III malocclusions compared to other craniofacial components, including the cranial base and mandible.
Cephalometry↗
Genetic diversity impacts of forest fires, forest harvesting, and alternative reforestation practices in black spruce (Picea mariana).
Benchmarks were established for genetic diversity inherent in natural mature populations, and genetic diversity impacts of forest fires, clearcut harvesting and alternative natural and artificial silvicultural regeneration practices were determined in black spruce (Picea mariana). Allozymes of 32 loci were used to determine and compare genetic diversity and genetic relationships of adjacent or nearby four stand types: post-fire natural mature (FNM), post-fire natural young (FNR), post-harvest natural young (HNR) and post-harvest plantation (PLT), of black spruce at each of the four study sites located in two ecoregions in Manitoba: Ecoregion 90-Lac Seul Upland (Eastern) and Ecoregion 158 - Mid-Boreal Lowland (Northern). Both allelic- and genotypic-based genetic diversity parameters, as well as latent genetic potential, were determined. Black spruce populations showed typical moderate to high levels of allozyme genetic diversity. The mean genetic diversity parameters over the 16 black spruce populations sampled were as follows: percent loci polymorphic - 67%, mean number of alleles per locus - 2.52, effective number of alleles per locus - 1.70, observed heterozygosity - 0.222, expected heterozygosity - 0.308, mean number of observed genotypes per locus - 3.65, mean number of expected genotypes per locus - 5.03, genotype additivity (observed) - 116.8, genotype additivity (expected) - 161, genotype multiplicity (observed) - 6.16 x 10(15), genotype multiplicity (expected) - 2.06 x 10(19) and latent genetic potential - 26.12. The four stand types (FNM, FNR, HNR and PLT) had comparable and statistically similar genetic diversity levels at each of the four study sites as well as overall. No significant differences in black spruce genetic diversity levels were observed between the two ecoregions in Manitoba, as well as between the post-fire and post-harvest regenerated stands. No particular order of genetic relatedness among the four stand types was observed. Black spruce populations showed some sort of site-related differentiation in their genetic constitution. Allelic heterogeneity and genetic distances among populations within stand types and among four stand types suggest that the genetic diversity was maintained at the landscape level in black spruce. The results of our study demonstrate that forest fires and currently used clearcut harvesting, and alternative natural and artificial silvicultural regeneration practices, do not adversely affect genetic diversity in black spruce, and that the genetic diversity effects of clearcut harvesting are not significantly different from those due to forest fires in black spruce.
Alleles↗
The cerebellar-vestibular basis of learning disabilities in children, adolescents and adults: hypothesis and study.
This paper provides a description of the cerebellar-vestibular-determined (CV) neurological and electronystagmographic (ENG) parameters characterizing 4,000 patients with learning disabilities. Of this sample, 1465 or 36.6% were children, 1156 or 28.9% adolescents, and 1379 or 34.5% adults. Using a set of diagnostic methods and criteria, the incidence of CV-dysfunction in this diverse sample was statistically equivalent to that reported by neurologists and neurotologists in a prior "blind" analysis of 115 dyslexic children. Over 94% of both the learning disabled and the dyslexic samples showed two or more abnormal neurological or ENG parameters indicating a CV-dysfunction whereas less than 1% evidenced hard neurological signs of a cerebral disorder. These and related data suggested that: (1) learning disabilities and dyslexia may be cerebellar-vestibular-based and reflect a single disorder and that (2) the varying academic, speech, concentration, activity, and related symptoms characterizing learning disabled persons seem to be shaped by a diverse group of cerebellar-vestibular-determining mechanisms rather than distinct neurophysiological disorders; also, (3) cerebellar-vestibular dysfunctioning and learning disabilities may secondarily trigger altered and/or compensatory cerebral processing and dominance mechanisms. (4) The cerebral cortex apparently plays a vital, compensatory role in shaping the final symptoms. A cerebellar-vestibular basis of learning disabilities is proposed. This conceptualization is consistent with, encompasses, and/or readily explains most of these clinical diagnostic, therapeutic, and research data as well as the many and varied hypotheses.
Adolescent↗