Search results for " variability"
showing 10 items of 853 documents
Time, frequency and information domain analysis of short-term heart rate variability before and after focal and generalized seizures in epileptic chi…
2019
OBJECTIVE In this work we explore the potential of combining standard time and frequency domain indexes with novel information measures, to characterize pre- and post-ictal heart rate variability (HRV) in epileptic children, with the aim of differentiating focal and generalized epilepsy regarding the autonomic control mechanisms. APPROACH We analyze short-term HRV in 37 children suffering from generalized or focal epilepsy, monitored 10 s, 300 s, 600 s and 1800 s both before and after seizure episodes. Nine indexes are computed in time (mean, standard deviation of normal-to-normal intervals, root mean square of the successive differences (RMSSD)), frequency (low-to-high frequency power rati…
Sympathetic tone and ventricular tachycardia
2008
Background The pathogenesis of idiopathic monomorphic ventricular tachycardia is not clear. We suppose that a lack of balance of the sympathetic system could be involved. Frequency domain analyses of the heart rate can be useful to understand autonomic system balance. Therefore we performed this evaluation on a sample of seven children affected by idiopathic monomorphic ventricular tachycardia. Methods and results We performed a Holter recording for palpitations on all the children, with an average age of 12 (range: 7-18 years). In all the patients many episodes of repeated sustained or nonsustained ventricular tachycardia were demonstrated, with an average heart rate of 170 bpm. We exclude…
Emotion–performance relationships in team sport: The role of personal and social identities
2018
IF 2018: 1.25 (Q2); International audience; In the field of emotion–performance relationship in achievement situations, the social dimensions of emotions have been understudied. Thus, recent advances highlighted the need to explore identity processes to know whether group belonging may influence individuals’ emotions and performance when they are involved in a task-group. The current study introduced an innovative approach to continuously capture the variability of emotions (pleasant and unpleasant), identity levels (personal and social) and performances (individual and collective) experienced during volleyball games. Six elite players (M = 20.14 years; SD = 1.25) volunteered to participate…
Assessment and inter-comparison of recently developed/reprocessed microwave satellite soil moisture products using ISMN ground-based measurements
2019
Soil moisture (SM) is a key state variable in understanding the climate system through its control on the land surface energy, water budget partitioning, and the carbon cycle. Monitoring SM at regional scale has become possible thanks to microwave remote sensing. In the past two decades, several satellites were launched carrying on board either radiometer (passive) or radar (active) or both sensors in different frequency bands with various spatial and temporal resolutions. Soil moisture algorithms are in rapid development and their improvements/revisions are ongoing. The latest SM retrieval products and versions of products that have been recently released are not yet, to our knowledge, com…
Diagnosis and predictability of intraseasonal characteristics of wet and dry spells over equatorial east Africa
2010
Most of Eastern Africa has arid and semi-arid climate with high space-time variability in rainfall. The droughts are very common in this region, and often persist for several years, preceded or followed by extreme floods. Most of the livelihoods and socio-economic activities however remain rain-dependent leading to severe negative impacts during the periods of occurrence of climate extremes. It has been noted that one extreme event was capable of reversing national economic growth made over a period of several years. Thus no sustainable development can be attained in eastern Africa without effective mainstreaming of climate information in the development policies, plans and programmes. Many…
Functional Brain Segmentation Using Inter-Subject Correlation in fMRI
2016
The human brain continuously processes massive amounts of rich sensory information. To better understand such highly complex brain processes, modern neuroimaging studies are increasingly utilizing experimental setups that better mimic daily‐life situations. A new exploratory data‐analysis approach, functional segmentation inter‐subject correlation analysis (FuSeISC), was proposed to facilitate the analysis of functional magnetic resonance (fMRI) data sets collected in these experiments. The method provides a new type of functional segmentation of brain areas, not only characterizing areas that display similar processing across subjects but also areas in which processing across subjects is h…
A method for the time-varying nonlinear prediction of complex nonstationary biomedical signals
2009
A method to perform time-varying (TV) nonlinear prediction of biomedical signals in the presence of nonstationarity is presented in this paper. The method is based on identification of TV autoregressive models through expansion of the TV coefficients onto a set of basis functions and on k -nearest neighbor local linear approximation to perform nonlinear prediction. The approach provides reasonable nonlinear prediction even for TV deterministic chaotic signals, which has been a daunting task to date. Moreover, the method is used in conjunction with a TV surrogate method to provide statistical validation that the presence of nonlinearity is not due to nonstationarity itself. The approach is t…
Spatial variation of soil magnetic susceptibility in relation to different emission sources in southern Poland
2015
Abstract The study in the area surrounding the Rybnik urban agglomeration (southern Poland) was conducted to determine the influence of various emission sources on the occurrence of local magnetic anomalies observed in the forest topsoils. For this reason field measurement of volume-specific magnetic susceptibility (κ) was conducted in forest topsoil on the area of study. The measurements were performed twice: directly on the surface and after removal of forest litter to see the influence of the litter on the magnetic signal measured on the soil surface. The maps of surface distribution of κ value revealed that magnetic anomalies were observed 2.0 km around the residential areas dominated b…
Assessment of the soil organic carbon stock in Spain
2016
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The role of social processes and decision making on the psychobiological response to social stress
2018
Los humanos, a diario, se enfrentan a diversas interacciones sociales, que pueden ser interpretadas como retos o como amenazas en función del contexto y del individuo que las enfrenta. Es por ello, que el cuerpo humano acaba activando sus mecanismos fisiológicos y conductuales en función de cómo interpreta está situación. Durante toda esta interpretación los humanos deciden un patrón de conducta que les lleva a tomar un tipo de decisiones u otras para adaptarse a estas interacciones sociales. Es por ello que la toma de decisiones puede ser una variable de estudio importante a lo largo de toda una interacción social, tanto como decidimos en función de la interacción y la respuesta fisiológic…