Search results for "STATISTICS"
showing 10 items of 7671 documents
Mixed predictability and cross-validation to assess non-linear Granger causality in short cardiovascular variability series
2006
A method to evaluate the direction and strength of causal interactions in bivariate cardiovascular and cardiorespiratory series is presented. The method is based on quantifying self and mixed predictability of the two series using nearest-neighbour local linear approximation. It returns two causal coupling indexes measuring the relative improvement in predictability along direct and reverse directions, and a directionality index indicating the preferential direction of interaction. The method was implemented through a cross-validation approach that allowed quantification of directionality without constraining the embedding of the series, and fully exploited the available data to maximise th…
Time-Varying Surrogate Data to Assess Nonlinearity in Nonstationary Time Series: Application to Heart Rate Variability
2009
We propose a method to extend to time-varying (TV) systems the procedure for generating typical surrogate time series, in order to test the presence of nonlinear dynamics in potentially nonstationary signals. The method is based on fitting a TV autoregressive (AR) model to the original series and then regressing the model coefficients with random replacements of the model residuals to generate TV AR surrogate series. The proposed surrogate series were used in combination with a TV sample entropy (SE) discriminating statistic to assess nonlinearity in both simulated and experimental time series, in comparison with traditional time-invariant (TIV) surrogates combined with the TIV SE discrimin…
Psychological intimate partner violence against women in the European Union: a cross-national invariance study
2019
Abstract Background Intimate partner violence against women (IPVAW) is a worldwide public health problem. One of the most frequent forms of this type of violence in western societies is psychological IPVAW. According to the European Union (EU) Fundamental Rights Association (FRA) the prevalence of psychological IPVAW in the EU is 43%. However, the measurement invariance of the measure addressing psychological IPVAW in this survey has not yet been assessed. Methods The aim of this study is to ensure the cross-national comparability of this measure, by evaluating its measurement invariance across the 28 EU countries in a sample of 37,724 women, and to examine how the levels of this type of vi…
Biliary sludge and gallstones in pregnancy: Incidence, risk factors, and natural history
1993
To evaluate the incidence and symptoms of and risk factors for biliary sludge and gallstones during pregnancy and to assess the natural history of these conditions in the first year after delivery.Cohort study.A total of 272 pregnant women recruited in the first trimester.Biliary sludge and gallstones were diagnosed using ultrasonography, both during pregnancy and after delivery. Predictors of the presence or disappearance of sludge and stones were examined.Overall, from the first trimester of pregnancy until the immediate postpartum period, 67 women were newly diagnosed with biliary sludge, and 6 women were newly diagnosed with gallstones. The respective incidence rates were 31% (95% Cl, 2…
Laparoscopic temporary clipping of uterine artery during laparoscopic myomectomy
2012
Purpose: Our aim is to study the feasibility and effect of bilateral laparoscopic temporary occlusion of uterine arteries by special vascular clamps on blood loss during laparoscopic myomectomy. Methods: Of 166 women with symptomatic uterine myomas necessitating surgical intervention who wished to retain their uteri, 80 underwent laparoscopic uterine artery clipping and myomectomy (experimental group) and 86 received laparoscopic myomectomy only (control group). Main outcome measures were operating time, number and weight of leiomyomas, blood loss, Doppler examination of the uterine arteries and complications of procedure. Results: In the experimental group the median hemoglobin drop measur…
Neural Network for Estimating Energy Expenditure in Paraplegics from Heart Rate
2014
The aim of the present study is to obtain models for estimating energy expenditure based on the heart rates of people with spinal cord injury without requiring individual calibration. A cohort of 20 persons with spinal cord injury performed a routine of 10 activities while their breath-by-breath oxygen consumption and heart rates were monitored. The minute-by-minute oxygen consumption collected from minute 4 to minute 7 was used as the dependent variable. A total of 7 features extracted from the heart rate signals were used as independent variables. 2 mathematical models were used to estimate the oxygen consumption using the heart rate: a multiple linear model and artificial neural networks…
Acoustic Airway Profiles in Unilateral Cleft Palate Patients
1999
Objective: This study investigates the nasal airway in unilateral cleft palate patients by means of a noninvasive, objective diagnostic method that provides topographic information about the airway profile. Design: A consecutive sample of patients was measured. Setting: Cleft palate rehabilitation center of the University of Mainz, Germany. Patients: Forty-nine subjects were investigated: 34 full-grown patients with complete unilateral cleft lip and palate and 15 controls with subjective normal nasal patency. Intervention: A transnasal series of three acoustic measurements of nasal volume was performed per nostril; measurements were taken both before and after decongestion with 0.3 mg xylom…
Facial disability index (FDI): adaptation to Spanish, reliability and validity.
2011
Objectives: To adapt to Spanish the facial disability index (FDI) described by VanSwearingen and Brach in 1995 and to assess its reliability and validity in patients with facial nerve paresis after parotidectomy. Study Design: The present study was conducted in two different stages: a) cross-cultural adaptation of the questionnaire and b) cross-sectional study of a control group of 79 Spanish-speaking patients who suffered facial paresis after superficial parotidectomy with facial nerve preservation. The cross-cultural adaptation process comprised the following stages: (I) initial translation, (II) synthesis of the translated document, (III) retro-translation, (IV) review by a board of expe…
A questionnaire assessing women's care needs related to gynaecological cancer screening: development of the GCSCNS.
2013
Abstract Objective To identify women's care needs concerning cancer screening and to develop an instrument suitable for measuring them – the Gynaecological Cancer Screening Care Needs Scale (GCSCNS). We hypothesized that it is possible: (a) to explore care needs and to develop reliable subscales of them, (b) to rank these needs in order of importance, and (c) to detect determinants of these needs (age, social status, marital status, health locus of control) and these need scores. Study design A questionnaire was developed based on the relevant literature, interviews conducted with gynaecological patients, and a consultation with 18 experts. The questionnaire listed 58 items addressed to phy…
Clinical parameters and aMMP-8-concentrations in gingival crevicular fluid in pregnancy gingivitis.
2013
BACKGROUND During pregnancy hormonal changes may increase the risk for developing gingivitis. The aim of this study was to evaluate the signs of gingival inflammation and the enzyme activity of matrix metalloproteinase-8 (aMMP-8) in the gingival crevicular fluid of pregnant women. METHODS After approval by the ethics commission, a total of 40 volunteers participated in the study; group 1 (n = 20, age: 32 +/- 4 years) with pregnant women, and group 2 (n = 20, age: 30 +/- 10 years) with age-matched non-pregnant women as controls. After obtaining anamnestic data, the dental examination included assessment of oral hygiene, gingival inflammation, probing pocket depth, and recession. Gingival cre…