Search results for "linear"
showing 10 items of 7165 documents
Covariation of spectral and nonlinear EEG measures with alpha biofeedback.
2002
Item does not contain fulltext This study investigated how different spectral and nonlinear EEG measures covaried with alpha power during auditory alpha biofeedback training, performed by 13 healthy subjects. We found a significant positive correlation of alpha power with the largest Lyapunov-exponent, pointing to an increased dynamical instability of the EEG accompanying alpha enhancement. Alpha power amplification, moreover, was significantly correlated with a decrease of spectral entropy within the alpha range. This outcome reflects a sharpening of the alpha peak during biofeedback training. The fact that the sharpening effect clearly preceded the increase of alpha amplitude could be exp…
Grey matter damage and overall cognitive impairment in primary progressive multiple sclerosis
2011
Objectives: To identify associations between cognitive impairment and imaging measures in a cross-sectional study of patients with primary progressive multiple sclerosis (PPMS). Methods: Neuropsychological tests were administered to 27 patients with PPMS and 31 controls. Patients underwent brain conventional magnetic resonance imaging (MRI) sequences, volumetric scans and magnetization transfer (MT) imaging; MT ratio (MTR) parameters, grey matter (GM) and normal-appearing white matter (NAWM) volumes, and WM T2 lesion load (T2LL) were obtained. In patients, multiple linear regression models identified the imaging measure associated with the abnormal cognitive tests independently from the ot…
Age-related satisfaction with complete dentures, desire for improvement and attitudes to implant treatment
1994
In the edentulous lower jaw implant stabilised dentures have proved clinically so successful that the indication for this treatment is now being discussed more often with geriatric patients. The aim of this study of edentate subjects was to determine the age-relation of the demand for denture improvement, the risks and feasibility of implant treatment. Sixty four complete denture wearers aged from 42 to 84 years took part in the study. A questionnaire was used to determine the subjective demand for denture improvement. For 33 subjects implants seemed possible. For these patients fear and scepticism concerning implant treatment were specified and quantified. Impaired general health was the m…
The significance of sperm DNA oxidation in embryo development and reproductive outcome in an oocyte donation program: a new model to study a male inf…
2008
Objective: One byproduct resulting from free radical damage is the DNA hydroxylation also known as DNA oxidation. Our aim with this work was to determine the relevance of sperm DNA oxidation on embryo quality in oocyte donation cycles. Design: We prospectively studied pairs of oocyte donation cycles, i.e., the same oocyte donors, donating to two recipients, where the only difference between the two treatments was the use of a different sperm sample. Setting: University-affiliated private IVF setting. Patient(s): Infertile male partners from couples undergoing oocyte donation cycles (n=38): 76 semen aliquots analyzed before and after semen processing by swim up. Intervention(s): None. Main O…
Corpus callosum area in patients with bipolar disorder with and without psychotic features: an international multicentre study
2015
Background Previous studies have reported MRI abnormalities of the corpus callosum (CC) in patients with bipolar disorder (BD), although only a few studies have directly compared callosal areas in psychotic versus nonpsychotic patients with this disorder. We sought to compare regional callosal areas in a large international multicentre sample of patients with BD and healthy controls. Methods We analyzed anatomic T-1 MRI data of patients with BD-I and healthy controls recruited from 4 sites (France, Germany, Ireland and the United States). We obtained the mid-sagittal areas of 7 CC subregions using an automatic CC delineation. Differences in regional callosal areas between patients and contr…
Motor Development and Physical Activity: A Longitudinal Discordant Twin-Pair Study.
2015
ntroduction : Previous longitudinal research suggests that motor proficiency in early life predicts physical activity in adulthood. Familial effects including genetic and environmental factors could explain the association, but no long-term follow-up studies have taken into account potential confounding by genetic and social family background. The present twin study investigated whether childhood motor skill development is associated with leisure-time physical activity levels in adulthood independent of family background. Methods : Altogether, 1550 twin pairs from the FinnTwin12 study and 1752 twin pairs from the FinnTwin16 study were included in the analysis. Childhood motor development wa…
Training at maximal power in resisted sprinting: Optimal load determination methodology and pilot results in team sport athletes.
2018
Aims: In the current study we investigated the effects of resisted sprint training on sprinting performance and underlying mechanical parameters (force-velocity-power profile) based on two different training protocols: (i) loads that represented maximum power output (Lopt) and a 50% decrease in maximum unresisted sprinting velocity and (ii) lighter loads that represented a 10% decrease in maximum unresisted sprinting velocity, as drawn from previous research (L10). Methods: Soccer [n = 15 male] and rugby [n = 21; 9 male and 12 female] club-level athletes were individually assessed for horizontal force-velocity and load-velocity profiles using a battery of resisted sprints, sled or robotic r…
Uncertainty quantification in simulations of epidemics using polynomial chaos.
2012
Mathematical models based on ordinary differential equations are a useful tool to study the processes involved in epidemiology. Many models consider that the parameters are deterministic variables. But in practice, the transmission parameters present large variability and it is not possible to determine them exactly, and it is necessary to introduce randomness. In this paper, we present an application of the polynomial chaos approach to epidemiological mathematical models based on ordinary differential equations with random coefficients. Taking into account the variability of the transmission parameters of the model, this approach allows us to obtain an auxiliary system of differential equa…
TESTING THE EFFECT OF THE EPIDEMIOLOGIC PARADOX: BIRTH WEIGHT OF NEWBORNS OF IMMIGRANT AND NON-IMMIGRANT MOTHERS IN THE REGION OF VALENCIA, SPAIN
2013
SummaryThe epidemiological paradox and ‘healthy migrant effect’ refer to the favourable health outcomes in unprivileged groups under unfavourable socioeconomic conditions. Weight at birth is associated with the epidemiological paradox. However, differences in fertility structure (mainly mother's age and first maternity) might be the cause of the difference in weight at birth between children of immigrant and non-immigrant mothers. This paper aims to analyse the impact of the epidemiologic paradox by distinguishing between the factors related to fertility structure, in addition to other socio-cultural factors. The importance of fertility structure as the cause of weight-at-birth differences …
Impaired Cardiopulmonary Exercise Capacity in Patients With Hyperthyroidism
1996
Hyperthyroidism (H) has been implicated as a primary cause of decreased exercise tolerance. To our knowledge, analysis of respiratory gas exchange, an efficient noninvasive method in evaluating cardiopulmonary capacity, has not been performed in patients with H.Using cardiopulmonary exercise testing, 12 consecutive women with Graves' H were examined and controlled in euthyroidism (E). Eighteen women with E, in whom cardiac catheterization had ruled out heart disease, served as control subjects (C).The ventilatory anaerobic threshold was determined by means of the V-slope method. Ergometry was performed with patients in a semisupine position using a continuous ramp protocol of 20 W/min. Echo…