Search results for " Variability"
showing 10 items of 853 documents
Comparing air quality indices aggregated by pollutant
2011
In this paper a new aggregate Air Quality Index (AQI) useful for describing the global air pollution situation for a given area is proposed. The index, unlike most of currently used AQIs, takes into account the combined effects of all the considered pollutants to human health. Its good performance, tested by means of a simulation plan, is confirmed by a comparison with two other indices proposed in the literature, one of which is based on the Relative Risk of daily mortality, considering an application to real data.
Allozyme electrophoresis: its application to rotifers
1998
Allozyme electrophoresis is a well established technique for revealing genetic variation that has given useful results in a wide range of organisms. However, in rotifers it has been applied scarcely and only in a few species. In this paper the methods of acetate allozyme electrophoresis are introduced, including laboratory setup, equipment and staining recipes that have been successfully applied to brachionid rotifers. In addition, the literature published on allozyme electrophoresis in rotifers is reviewed and the main results and future prospects of the technique are discussed. We conclude that, despite the onset of DNA techniques, allozyme electrophoresis is promising and can yield impor…
Human Heart-Related Indexes Behavior Study for Aircraft Pilots Allowable Workload Level Assessment
2022
This study aimed to evaluate workload by detecting Heart Rate Variability (HRV) indexes in a sample of 34 pilots (with a mean age of 33 years) while performing simulated flight exercises. A one-way ANOVA with repeated measures was performed to assess the changes of the physiological measures in five standard maneuvers associated with different workload levels. The results show that all the indexes, but the Low Frequency to High Frequency ratio index (LF/HF), have a well-defined trend between the baseline and the en-route phase and with the three phases takeoff, steady turn, and landing. This study, as main findings, provides evidence of a differentiation among low, medium, and high workload…
Extending the spectral decomposition of Granger causality to include instantaneous influences: application to the control mechanisms of heart rate va…
2021
Assessing Granger causality (GC) intended as the influence, in terms of reduction of variance of surprise, that a driver variable exerts on a given target, requires a suitable treatment of ‘instantaneous’ effects, i.e. influences due to interactions whose time scale is much faster than the time resolution of the measurements, due to unobserved confounders or insufficient sampling rate that cannot be increased because the mechanism of generation of the variable is inherently slow (e.g. the heartbeat). We exploit a recently proposed framework for the estimation of causal influences in the spectral domain and include instantaneous interactions in the modelling, thus obtaining (i) a novel index…
Molecular characterization can quantify and partition variation among genebank holdings: a case study with phenotypically similar accessions of Brass…
1997
To better characterize and conserve crop genetic resources, the assessment of genetic identity, relatedness, and structure among entries and collections becomes a priority. In the present study, a random amplified polymorphic DNA (RAPD) assay was applied as a quick, cost-effective, and preliminary screen to quantify and partition the molecular variation among accessions. Fourteen phenotypically uniform accessions of Brassica oleracea var. capitata L. (cabbage) similarly designated as `Golden Acre' were tested with nine decamer oligonucleotide primers. These amplifications generated 110 fragments, of which 80 were polymorphic ranging in size from 370 to 1720 bp. The 80 polymorphic fragments …
Genetic variability at neutral markers, quantitative trait loci and trait in a subdivided population under selection
2003
Abstract Genetic variability in a subdivided population under stabilizing and diversifying selection was investigated at three levels: neutral markers, QTL coding for a trait, and the trait itself. A quantitative model with additive effects was used to link genotypes to phenotypes. No physical linkage was introduced. Using an analytical approach, we compared the diversity within deme (HS) and the differentiation (FST) at the QTL with the genetic variance within deme (VW) and the differentiation (QST) for the trait. The difference between FST and QST was shown to depend on the relative amounts of covariance between QTL within and between demes. Simulations were used to study the effect of se…
Genetic background in nonalcoholic fatty liver disease: A comprehensive review
2015
In the Western world, nonalcoholic fatty liver disease (NAFLD) is considered as one of the most significant liver diseases of the twenty-first century. Its development is certainly driven by environmental factors, but it is also regulated by genetic background. The role of heritability has been widely demonstrated by several epidemiological, familial, and twin studies and case series, and likely reflects the wide inter-individual and inter-ethnic genetic variability in systemic metabolism and wound healing response processes. Consistent with this idea, genome-wide association studies have clearly identified Patatin-like phosholipase domain-containing 3 gene variant I148M as a major player i…
Genetic variability in a narrow endemic snapdragon (Antirrhinum subbaeticum, Scrophulariaceae) using RAPD markers
2002
Antirrhinum subbaeticum is an endangered species inhabiting fragmented limestone cliffs. In the last 3 years, a drastic population decline has been observed in three of four known populations and the estimated number of surviving individuals is now close to 400. A RAPD study was conducted to evaluate the levels of genetic variation present in this species to improve conservation guidelines. Thirty-nine polymorphic products identified 66.1% of the samples by unique RAPD multilocus profiles. A cluster analysis grouped the samples into two broad groups corresponding to northern or southern provenances. AMOVA analysis showed that only 17.7% of the genetic diversity was partitioned within popula…
RAD SNP markers as a tool for conservation of dolphinfish Coryphaena hippurus in the Mediterranean Sea: Identification of subtle genetic structure an…
2016
Dolphinfish is an important fish species for both commercial and sport fishing, but so far limited information is available on genetic variability and pattern of differentiation of dolphinfish populations in the Mediterranean basin. Recently developed techniques allow genome-wide identification of genetic markers for better understanding of population structure in species with limited genome information. Using restriction-site associated DNA analysis we successfully genotyped 140 individuals of dolphinfish from eight locations in the Mediterranean Sea at 3324 SNP loci. We identified 311 sex-related loci that were used to assess sex-ratio in dolphinfish populations. In addition, we identifie…
Genetic variability ofTriatoma rubrovaria(Reduviidae: Triatominae) from Brazil, Argentina and Uruguay as revealed by two different molecular markers
2007
Randomly amplified polymorphic DNA (RAPD) and nuclear ribosomal DNA sequence analyses were used to assess the genetic population structure of the South American triatomine species Triatomo rubrovario throughout its geographical distribution. To investigate the genetic variability at both intraspecific and intrapopulational levels the RAPD profiles and the nucleotide sequences of the rDNA intergenic spacers, ITS-1 and ITS-2, were analysed and compared. The phenetic analysis based on RAPD profiles show three distinct clusters diverging by similarity coefficients ranging from 0.62 to 0.96. The ITS-1 and ITS-2 sequence variability detected may be considered very high, suggesting reproductive is…