Search results for "Variability"
showing 10 items of 904 documents
Towards a resolution of the lek paradox
2001
Genetic benefits in the shape of 'good genes' have been invoked to explain costly female choice in the absence of direct fitness benefits. Little genetic variance in fitness traits is expected, however, because directional selection tends to drive beneficial alleles to fixation. There seems to be little potential, therefore, for female choice to result in genetic benefits, giving rise to the 'lek paradox'. Nevertheless, evidence shows that genetic variance persists despite directional selection and genetic benefits of female choice are frequently reported. A theoretical solution to the lek paradox has been proposed on the basis of two assumptions: that traits are condition-dependent, and th…
Univariate and multivariate conditional entropy measures for the characterization of short-term cardiovascular complexity under physiological stress
2017
Objective: A defining feature of physiological systems under the neuroautonomic regulation is their dynamical complexity. The most common approach to assess physiological complexity from short-term recordings, i.e. to compute the rate of entropy generation of an individual system by means of measures of conditional entropy (CE), does not consider that complexity may change when the investigated system is part of a network of physiological interactions. This study aims at extending the concept of short-term complexity towards the perspective of network physiology, defining multivariate CE measures whereby multiple physiological processes are accounted for in the computation of entropy rates.…
Basic cardiovascular variability signals: mutual directed interactions explored in the information domain.
2017
The study of short-term cardiovascular interactions is classically performed through the bivariate analysis of the interactions between the beat-to-beat variability of heart period (RR interval from the ECG) and systolic blood pressure (SBP). Recent progress in the development of multivariate time series analysis methods is making it possible to explore how directed interactions between two signals change in the context of networks including other coupled signals. Exploiting these advances, the present study aims at assessing directional cardiovascular interactions among the basic variability signals of RR, SBP and diastolic blood pressure (DBP), using an approach which allows direct compar…
Interobserver variability in rectum contouring in high-dose-rate brachytherapy for prostate cancer: A multi-institutional prospective analysis
2017
PURPOSE: The aim of this study was to evaluate the interobserver variability (KW) of rectum contouring, and its dosimetric consequences, for high-dose-rate brachytherapy in patients with prostate cancer across multiple institutions. METHODS AND MATERIALS: Five radiation oncologists contoured rectums in 10 patients on transperineal ultrasound image sets after establishing a delineation consensus. The D-0.1cc, D-1cc, and D-2cc rectum volume parameters were determined. The mean, standard deviation, and range of each dose-volume histogram parameter were evaluated for each patient. The JOY was determined using the coefficient of variation, and the dosimetric impacts on the total dose were analyz…
Thermal Thresholds Predict Painfulness of Diabetic Neuropathies
2004
OBJECTIVE—Pathophysiology explaining pain in diabetic neuropathy (DN) is still unknown. RESEARCH DESIGN AND METHODS—Thirty patients with peripheral DN (17 men and 13 women; mean age 52.4 ± 2.5 years) were investigated. Fifteen patients had neuropathic pain, and 15 patients were free of pain. Patients were followed over 2 years and examined at the beginning and thereafter every 6 months. Clinical severity and painfulness of the DN were assessed by the neuropathy impairment score and visual analog scales (VASs). Cold and warm perception thresholds as well as heat pain thresholds were obtained for evaluation of Aδ- and C-fibers. Nerve conduction velocities (NCVs) and vibratory thresholds were …
Rare variants in the genetic background modulate cognitive and developmental phenotypes in individuals carrying disease-associated variants
2019
Purpose: To assess the contribution of rare variants in the genetic background toward variability of neurodevelopmental phenotypes in individuals with rare copy-number variants (CNVs) and gene-disruptive variants. Methods: We analyzed quantitative clinical information, exome sequencing, and microarray data from 757 probands and 233 parents and siblings who carry disease-associated variants. Results: The number of rare likely deleterious variants in functionally intolerant genes (“other hits”) correlated with expression of neurodevelopmental phenotypes in probands with 16p12.1 deletion (n=23, p=0.004) and in autism probands carrying gene-disruptive variants (n=184, p=0.03) compared with thei…
Agreement between parent and child report on parental practices regarding dietary, physical activity and sedentary behaviours: the ENERGY cross-secti…
2014
Background Parents and their parenting practices play an important role in shaping their children’s environment and energy-balance related behaviours (EBRBs). Measurement of parenting practices can be parent- or child-informed, however not much is known about agreement between parent and child perspectives. This study aimed to assess agreement between parent and child reports on parental practices regarding EBRBs across different countries in Europe and to identify correlates of agreement. Methods Within the ENERGY-project, a cross-sectional survey was conducted among 10–12 year old children and their parents in eight European countries. Both children and parents filled in a questionnaire o…
The impact of the degree of obesity on the discrepancies between office and ambulatory blood pressure values in youth.
2006
Objectives Obesity is an increasingly frequent problem among children and adolescents, and may lead to blood pressure (BP) increase. The aim of the present study was to assess the prevalence of hypertension, white-coat and masked hypertension in obese adolescents making systematic use of both office BP and 24-h ambulatory BP measurement. The impact of different degrees of obesity on BP and heart rate variability was also investigated. Methods Office and ambulatory BP were obtained in 285 overweight and obese Caucasian adolescents (11–18 years old) and in 180 age- and sex-matched controls. The extent of obesity was quantified using body mass index z score. Results A significant positive rela…
Aquatic cycling-What do we know? A scoping review on head-out aquatic cycling
2017
Over the past few years, aquatic cycling has become a trending fitness activity. However, the literature has not been reviewed exhaustively. Therefore, using scoping review methodology, the aim of this review was to explore the current state of the literature concerning aquatic cycling. This study specifically focused on study designs, populations and outcomes. A comprehensive search of seven databases (PubMed, MEDLINE, Cinahl, Embase, PEDro, Web of Science, WorldCat) was conducted up to 30th September 2016. GoogleScholar, World Cat, ResearchGate, specific aquatic therapy websites and aquatic therapy journals were searched to identify additional literature. Full-text publications in English…
The reliability of continuous brain responses during naturalistic listening to music
2015
Low-level (timbral) and high-level (tonal and rhythmical) musical features during continuous listening to music, studied by functional magnetic resonance imaging (fMRI), have been shown to elicit large-scale responses in cognitive, motor, and limbic brain networks. Using a similar methodological approach and a similar group of participants, we aimed to study the replicability of previous findings. Participants' fMRI responses during continuous listening of a tango Nuevo piece were correlated voxelwise against the time series of a set of perceptually validated musical features computationally extracted from the music. The replicability of previous results and the present study was assessed b…