Search results for " variability"
showing 10 items of 853 documents
Spatial and temporal characteristics of potential evapotranspiration trends over China
2000
This paper analyses the time series (1954–1993) of Penman–Monteith evapotranspiration estimates for 65 stations in mainland China and Tibet, for the country as a whole and for individual stations. The analysis shows that for China as a whole, the potential evapotranspiration (PET) has decreased in all seasons. On a regional basis, northeast and southwest China have experienced moderate evapotranspiration increases, while in northwest and southeast China evapotranspiration has decreased to a much higher extent. South of 35°N, sunshine appears to be most strongly associated with evapotranspiration changes while wind, relative humidity and maximum temperature are the primary factors in northwe…
The relationship between ADHD and key cognitive phenotypes is not mediated by shared familial effects with IQ
2011
BackgroundTwin and sibling studies have identified specific cognitive phenotypes that may mediate the association between genes and the clinical symptoms of attention deficit hyperactivity disorder (ADHD). ADHD is also associated with lower IQ scores. We aimed to investigate whether the familial association between measures of cognitive performance and the clinical diagnosis of ADHD is mediated through shared familial influences with IQ.MethodMultivariate familial models were run on data from 1265 individuals aged 6–18 years, comprising 920 participants from ADHD sibling pairs and 345 control participants. Cognitive assessments included a four-choice reaction time (RT) task, a go/no-go task…
Assessment of cardiac autonomic nervous activity in frail elderly people with postural abnormalities and in control subjects
2008
Heart rate variability (HRV), which is considered to reflect the activity of the autonomic nervous system (ANS), has been shown to decline with age. The aim of the present study was to explore cardiac ANS in older patients showing frontal-subcortical dysfunction with "Psychomotor Disadaptation Syndrome" (PDS), through the 24-h HRV. We enrolled 14 patients with PDS (mean age: 84.5+/-6.9 years), they were compared to 13 frail control subjects (mean age: 80.6+/-6.7 years). Cardiac ANS activity was assessed by 24-h ECG recordings from three leads with a Holter digital monitor. The decrease in cardiac ANS activity observed in PDS subjects was greater than the alteration found in normally aging s…
High N-Terminal Pro-B-Type Natriuretic Peptide Levels Are Associated with Reduced Heart Rate Variability in Acute Myocardial Infarction
2012
AIM: We investigated the relationships between the autonomic nervous system, as assessed by heart rate variability (HRV) and levels of N-terminal Pro-B-type Natriuretic Peptide (Nt-proBNP) in patients with acute myocardial infarction (MI). METHODS AND RESULTS: The mean of standard deviation of RR intervals (SDNN), the percentage of RR intervals with >50 ms variation (pNN50), square root of mean squared differences of successive RR intervals (rMSSD), and frequency domain parameters (total power (TP), high frequency and low frequency power ratio (LF/HF)) were assessed by 24 h Holter ECG monitoring. 1018 consecutive patients admitted <24 h for an acute MI were included. Plasma Nt-proBNP (Elecs…
Influences of baseline heart rate variability on repeated sprint performance in young soccer players
2015
AIM: The aim of this study was to assess the influence of the autonomic system on the performance of repeated sprints, involving predominantly neuromuscular power, in young soccer players. METHODS: Twelve young soccer players, selected for the Sicilian Regional Football Representative, mean age 15 years, were recruited. Baseline heart rate variability (HRV) was measured and indices of power spectral analysis (LF, HF, and ratio LF/HF) were calculated to evaluate the sympathovagal balance. The athletes performed 10 maximal 6--sec cycling sprints (RS), interspersed with 30--sec of recovery, to measure the peak power output (PP) represented by the highest power value recorded during a 6--sec sp…
Interleukin-10 and interleukin-18 promoter polymorphisms in an Italian cohort of patients with undifferentiated carcinoma of nasopharyngeal type.
2004
Purpose: Cytokines such as IL-10 and IL-18 seem to be involved in the inflammatory response of undifferentiated carcinoma of nasopharyngeal type (UCNT). The aim of this study was to evaluate the correlation between functional single nucleotide polymorphisms (SNPs) in the promoter region of IL-10 and IL-18 genes and the virological and clinical characteristics in a large case series of Caucasian patients suffering from UCNT, a tumor regularly associated with the Epstein Barr Virus (EBV). Methods: Eighty-nine patients with histologically confirmed UCNT and 130 healthy donors were included in our study. DNA was examined for the polymorphisms of IL-10 gene at positions –1082, −819, −592 by dire…
Recovery from sauna bathing favorably modulates cardiac autonomic nervous system
2019
Objective: Sauna bathing is becoming a common activity in many countries and it has been linked to favorable health outcomes. However, there is limited data on the heart rate (HR) and heart rate variability (HRV) responses to an acute sauna exposure. Design: We conducted a single-group, longitudinal study utilizing a pre-post design to examine acute effects of sauna bathing on the autonomic nervous system as reflected by HRV. A total of 93 participants (mean [SD] age: 52.0 [8.8] years, 53.8% males) with cardiovascular risk factors were exposed to a single sauna session (duration: 30 min; temperature: 73 °C; humidity: 10–20%) and data on HRV variables were collected before, during and after …
Use of heart rate variability in monitoring stress and recovery in judo athletes
2013
The main objective of this study was to examine the effect of different judo training loads on heart rate variability (HRV) measurements, to determine if they can be used as valid indicators in monitoring stress and recovery in judo athletes. Fourteen male national-standard judo athletes were randomly divided into 2 groups, and each group followed a different type of training, namely, a high training load (HTL) and a moderate training load program (MTL). Data collection included HRV measurements, a Recovery Stress Questionnaire for athletes (RESTQ-SPORT), and strength measurements, 4 weeks before and after the training program. The HTL group had lower square root of the mean squared differe…
From pioneering to implementing automated blood pressure measurement in clinical practice: Thomas Pickeringʼs legacy
2010
Thomas G. Pickering spent most of his scientific career in carrying out research on clinical hypertension and blood pressure (BP) measurement. In our review of Pickering's seminal work, we first focused on white-coat hypertension and masked hypertension, two terms that he had introduced. Next, we highlighted the early publications of Pickering on diurnal BP variability and on the clinical application of self-measured BP. Pickering's work inspired many investigators worldwide and constituted a solid basis for further research. Pickering's original ideas led to algorithms for risk stratification involving white-coat hypertension and masked hypertension, diurnal BP variability, and self-measur…
Genetic polymorphism and high detrimental load in natural populations of Drosophila melanogaster from cellar and vineyard
1987
Two Spanish natural populations of Drosophila melanogaster have been analysed with respect to genetic variability in third chromosome viability. The two populations, although from the same locality, belong to relatively different habitats: the inside of a cellar and a vineyard. The patterns of homozygote and heterozygote viability are similar in both populations. The homozygous detrimental loads estimated are very high and the values for the D:L (detrimental/lethal) ratio close to 2.5, which is higher than any previously found. The environmental variance of viability, average degrees of dominance of lethal genes and of viability polygenes and effective population sizes were estimated in eac…