Search results for " Variability"
showing 10 items of 853 documents
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…
Canal construction destroys the barrier between major European invasion lineages of the zebra mussel.
2002
Since the mid-1980s the zebra mussel, Dreissena polymorpha, Pallas 1771, has become the protagonist of a spectacular freshwater invasion in North America due to its large economic and biological impact. Several genetic studies on American populations have failed to detect any large-scale geographical patterns. In western Europe, where D. polymorpha has been a classical invader from the Pontocaspian since the early 19th century, the situation is strikingly different. Here, we show with genetic markers that two major western European invasion lineages with lowered genetic variability within and among populations can be discriminated. These two invasion lineages correspond with two separate na…
Reduction of depressive symptoms during inpatient treatment is not associated with changes in heart rate variability
2021
Vagally mediated heart rate variability (HRV) is a psychophysiological indicator of mental and physical health. Limited research suggests there is reduced vagal activity and resulting lower HRV in patients with Major Depressive Disorder (MDD); however little is actually known about the association between HRV and symptoms of depression and whether the association mirrors symptom improvement following psychotherapy. The aim of this study was to investigate the association between antidepressant therapy, symptom change and HRV in 50 inpatients (68% females; 17–68 years) with a diagnosis of MDD. Severity of depressive symptoms was assessed by self-report (Beck Depression Inventory II) and the …
Genetic variation in neuromuscular performance.
1973
Using a simple cumulative model of heredity plus environment, based on intrapair differences observed in monozygous (MZ) and dizygous (DZ) twins, the relative contribution of heredity to the interindividual variance in several neuromuscular parameters was determined with 15 pairs of male (8 MZ and 7 DZ) and 14 pairs of female (7 MZ and 7 DZ) twins ranging in age from 10 to 14 years. The data disclosed that in boys the variability in maximal mechanical (anaerobic) power was 99.2% genetically determined under the environmental conditions of the study. The corresponding heritability estimate values for the patellar reflex time and reaction time were 97.5% and 85.7%, respectively. In girls the …
Comparison of short-term heart rate variability indexes evaluated through electrocardiographic and continuous blood pressure monitoring
2019
Heart rate variability (HRV) analysis represents an important tool for the characterization of complex cardiovascular control. HRV indexes are usually calculated from electrocardiographic (ECG) recordings after measuring the time duration between consecutive R peaks, and this is considered the gold standard. An alternative method consists of assessing the pulse rate variability (PRV) from signals acquired through photoplethysmography, a technique also employed for the continuous noninvasive monitoring of blood pressure. In this work, we carry out a thorough analysis and comparison of short-term variability indexes computed from HRV time series obtained from the ECG and from PRV time series …
Does sympathetic overactivation feature all hypertensives? Differences of sympathovagal balance according to night/day blood pressure ratio in patien…
2015
When evaluating the 'night/day BP ratio', both hypertensives and normotensives can be arbitrarily classified into four groups: extreme dippers (ratio ⩽0.8), dippers (0.8<ratio ⩽0.9), mild dippers (0.9<ratio⩽1.0) and reverse dippers (ratio ⩾1.0). Reverse and mild dipper hypertensives have poorer prognoses compared with the physiological dipper profile, but the prognostic relevance of the extreme dipper profile remains uncertain. The evaluation of heart rate variability (HRV), obtained by 24-h Holter ECG monitoring, is the most frequently used noninvasive form of assessment of the activity of the autonomic nervous system. Reverse and mild dipper hypertensives have reduced HRV, indicating an o…
Linear and non-linear brain-heart and brain-brain interactions during sleep.
2015
In this study, the physiological networks underlying the joint modulation of the parasympathetic component of heart rate variability (HRV) and of the different electroencephalographic (EEG) rhythms during sleep were assessed using two popular measures of directed interaction in multivariate time series, namely Granger causality (GC) and transfer entropy (TE). Time series representative of cardiac and brain activities were obtained in 10 young healthy subjects as the normalized high frequency (HF) component of HRV and EEG power in the δ, θ, α, Ï, and β bands, measured during the whole duration of sleep. The magnitude and statistical significance of GC and TE were evaluated between each …
Time-on-Task in Children with ADHD: An ex-Gaussian Analysis
2013
AbstractAlthough it is widely known that high intra-individual variability (IIV) is a key characteristic of attention deficit/hyperactivity disorder (ADHD), a detailed exploration of the IIV pattern during the time course of a cognitive task has never been carried out. In this study, 30 children with ADHD and 30 controls, were administered the Conners’ Continuous Performance Task (CPT-II). The across-block individual performance of the groups was analyzed using an ex-Gaussian approach, which enabled a clearer understanding of how individual response times (RTs) fluctuate during a task in comparison with conventional measures of central tendency. While the conventional measures showed a sign…
Computer assisted morphometric analysis of ram sperm heads: Evaluation of different fixative techniques
1998
The recent development of automated systems for morphometric sperm head analysis has provided a series of objective parameters which have facilitated the standardization of morphological semen evaluation. This current work attempts to establish the optimum fixing conditions for the morphometric characterization of ram spermatozoa. Ejaculates were obtained from 5 Merino rams used for periodic collection of semen and were diluted at 1:50 with TEST medium. Air-dried smears were fixed either in ethanol-ether (1:1), 50% methanol, 2% glutaraldehyde or SUZA fixative, in which case the smear was pretreated with chloramine. The samples were then stained with commercial kit Hemacolor. Once the prepar…