Search results for "Variation"
showing 10 items of 2124 documents
Análisis tiempo-frecuencia de la fibrilación ventricular. Estudio experimental
2006
Introduction and objectives. The analysis of frequency variability during ventricular fibrillation has yielded inconsistent results. We used an experimental model of ventricular fibrillation, with a short timescale, to analyze variations in frequency and their associated spatial distribution. Methods. Epicardial recordings of ventricular fibrillation were made in 10 perfused isolated rabbit heart preparations using a multiple electrode system (i.e., 240 unipolar electrodes). Both spectral and time-frequency analysis were used to derive the dominant frequency in the anterolateral wall of the left ventricle. Results. Linear regression analysis showed that there was a good correlation between …
Variation in the Senecio aethnensis group (Asteraceae) along an altitudinal gradient
2003
ABSTRACT The variability of the Senecio aethnensis group was investigated through morphometric analyses of seven populations along an altitudinal transect on Mt. Etna (E Sicily). The data obtained show a separation into two groups, one including the populations of the upper and middle belts, at and above 1700 m, the other including the populations from lower altitudes. In the first group a clinal morphological variation in several reproductive and vegetative characters was observed in relation to altitude. The analysis of leaf characters in progeny cultivated under uniform conditions confirmed the differentiation into the two groups, which are to be treated as separate species, i.e. S. aeth…
Genetic basis of trichome production in Arabidopsis lyrata.
2002
Leaf trichomes may protect plants against herbivorous insects, and may increase tolerance to drought and UV-radiation. The perennial herb Arabidopsis lyrata (Brassicaceae) is polymorphic for trichome production and occurs in a glabrous and trichome-producing form. In addition, there is quantitative variation in trichome density among trichome-producing plants. To examine the genetic basis of glabrousness, we conducted controlled crosses with plants originating from two natural populations in Sweden (one polymorphic for trichome-production, and one consisting of glabrous plants only). In addition, we estimated the heritability of trichome number from parent-offspring regressions for plants o…
Molecular surveillance of norovirus, 2005–16 : an epidemiological analysis of data collected from the NoroNet network
2018
BACKGROUND: The development of a vaccine for norovirus requires a detailed understanding of global genetic diversity of noroviruses. We analysed their epidemiology and diversity using surveillance data from the NoroNet network.METHODS: We included genetic sequences of norovirus specimens obtained from outbreak investigations and sporadic gastroenteritis cases between 2005 and 2016 in Europe, Asia, Oceania, and Africa. We genotyped norovirus sequences and analysed sequences that overlapped at open reading frame (ORF) 1 and ORF2. Additionally, we assessed the sampling date and country of origin of the first reported sequence to assess when and where novel drift variants originated.FINDINGS: W…
Geographic Variations in Cardiometabolic Risk Factors in Luxembourg
2017
Cardiovascular disease (CVD) and associated behavioural and metabolic risk factors constitute a major public health concern at a global level. Many reports worldwide have documented different risk profiles for populations with demographic variations. The objective of this study was to examine geographic variations in the top leading cardio metabolic and behavioural risk factors in Luxembourg, in order to provide an overall picture of CVD burden across the country. The analysis conducted was based on data from the nationwide ORISCAV-LUX survey, including 1432 subjects, aged 18-69 years. A self-reported questionnaire, physical examination and blood sampling were performed. Age and sex-adjuste…
Force-velocity profiling in athletes: Reliability and agreement across methods
2021
The aim of the study was to examine the test-retest reliability and agreement across methods for assessing individual force-velocity (FV) profiles of the lower limbs in athletes. Using a multicenter approach, 27 male athletes completed all measurements for the main analysis, with up to 82 male and female athletes on some measurements. The athletes were tested twice before and twice after a 2- to 6-month period of regular training and sport participation. The double testing sessions were separated by ~1 week. Individual FV-profiles were acquired from incremental loading protocols in squat jump (SJ), countermovement jump (CMJ) and leg press. A force plate, linear encoder and a flight time cal…
Independence between developmental stability and canalization in the skull of the house mouse.
2000
The relationship between the two components of developmental homeostasis, that is canalization and developmental stability (DS), is currently debated. To appraise this relationship, the levels and morphological patterns of interindividual variation and fluctuating asymmetry were assessed using a geometric morphometric approach applied to the skulls of laboratory samples of the house mouse. These three samples correspond to two random-bred strains of the two European subspecies of the house mouse and their F1 hybrids. The inter- and intraindividual variation levels were found to be smaller in the hybrid group compared to the parental ones, suggesting a common heterotic effect on skull canali…
Absolutely continuous variational measures of Mawhin's type
2011
Abstract In this paper we study absolutely continuous and σ-finite variational measures corresponding to Mawhin, F- and BV -integrals. We obtain characterization of these σ-finite variational measures similar to those obtained in the case of standard variational measures. We also give a new proof of the Radon-Nikodým theorem for these measures.
Anatomical variations of the internal jugular vein: The role of ultrasonography
2014
Purpose: In many places, especially in emergency department, central venous catheter is still inserted using anatomical landmark guidance with a success rate up to 97.6% and complications up to 15%. This study was aimed to determine by the support of ultrasono-graphy (US) the anatomical variations of the internal jugular vein (IJV) in relation with other structures of the neck, such as the common carotid artery (CCA). Material and Methods: 830 patients requiring central vein catheterization (CVC) were in-cluded in the analysis. The position of the IJV in relation to the other structures of the neck was demonstrated by portable ultrasonography. Results: The mean diameter of IJV was 10.3 mm i…
An extended version of the theory of planned behavour: Prediction of intentions to quit smoking using past behaviour as moderator
2010
It was hypothesised that: (i) intentions to quit smoking were predictable from group identity, self-identity, moral norms and past quit attempts, beyond the components of the Theory of Planned Behaviour (TPB), and (ii) that past experiences with the behaviour (quit attempts) would increase the predictive utility of the extended TPB model on intentions. The data was collected among 357 daily smoking students (M = 24 years). The TPB components accounted for 12.3% of the variance in quitting intentions, while the extension variables added 16.5% to the explained variance in intentions beyond the impact of the TPB. Past behaviour had the strongest impact on intentions (α = 0.30), followed by mor…