Search results for "multivariate statistic"
showing 10 items of 327 documents
Health literacy of pregnant women and duration of breastfeeding maintenance: a feasibility study
2020
Research the association between health literacy (HL) and exclusive breastfeeding at 4-months postpartum.Despite the benefits of breastfeeding (BF), its rates are low worldwide. Among the reasons for abandonment is the level of maternal education. Maternal education has been associated with HL, but evidence between HL and BF maintenance is limited.A cross-sectional study.The sample compromised 229 nursing mothers recruited from January 2018 to the end of December 2018 at Spain by systematic sampling method. Women were interviewed postpartum on parameters associated with the start and continuation of BF up to 4 months postpartum. Multivariate logistic regression models to explain exposure va…
Non-Parametric Rank Statistics for Spectral Power and Coherence
2019
AbstractDespite advances in multivariate spectral analysis of neural signals, the statistical inference of measures such as spectral power and coherence in practical and real-life scenarios remains a challenge. The non-normal distribution of the neural signals and presence of artefactual components make it difficult to use the parametric methods for robust estimation of measures or to infer the presence of specific spectral components above the chance level. Furthermore, the bias of the coherence measures and their complex statistical distributions are impediments in robust statistical comparisons between 2 different levels of coherence. Non-parametric methods based on the median of auto-/c…
Adaptive independent vector analysis for multi-subject complex-valued fMRI data.
2017
Abstract Background Complex-valued fMRI data can provide additional insights beyond magnitude-only data. However, independent vector analysis (IVA), which has exhibited great potential for group analysis of magnitude-only fMRI data, has rarely been applied to complex-valued fMRI data. The main challenges in this application include the extremely noisy nature and large variability of the source component vector (SCV) distribution. New method To address these challenges, we propose an adaptive fixed-point IVA algorithm for analyzing multiple-subject complex-valued fMRI data. We exploited a multivariate generalized Gaussian distribution (MGGD)- based nonlinear function to match varying SCV dis…
Combination of mid- and near-infrared spectroscopy for the determination of the quality properties of beers
2006
Abstract The combination of infrared (MIR) and near-infrared (NIR) spectroscopy has been employed for the determination of important quality parameters of beers, such as original and real extract and alcohol content. A population of 43 samples obtained from the Spanish market and including different types of beer, was evaluated. For each technique, spectra were obtained in triplicate. In the case of NIR a 1 mm pathlength quartz flow cell was used, whereas attenuated total reflectance measurements were used in MIR. Cluster hierarchical analysis was employed to select calibration and validation data sets. The calibration set was composed of 15 samples, thus leaving 28 for validation. A critic…
Pre- and post-ictal brain activity characterization using combined source decomposition and connectivity estimation in epileptic children
2019
In this research, the study of functional connectivity between sources of electroencephalogram (EEG) activity assessed for different classes (well before seizure, preictal and post-ictal) was performed. EEG recordings were acquired from 12 subjects with focal epilepsy. Then, ten common spatial patterns (CSP) were obtained for EEG segments describing 95% of Riemannian distance between pairs of classes, followed by estimation of multivariate autoregressive (MVAR) models’ coefficients. The MVAR models were further used to extract coherence as a functional connectivity measures. Our results show that the coherence between CSP sources differs between baseline and pre-ictal segments: it has the l…
Partial least squares X-ray fluorescence determination of trace elements in sediments from the estuary of Nerbioi-Ibaizabal River.
2010
The feasibility of partial least squares (PLS) regression modeling of X-ray fluorescence (XRF) spectra of estuarine sediments has been evaluated as a tool for rapid trace element content monitoring. Multivariate PLS calibration models were developed to predict the concentration of Al, As, Cd, Co, Cr, Cu, Fe, Mg, Mn, Ni, Pb, Sn, V and Zn in sediments collected from different locations across the estuary of the Nerbioi-Ibaizabal River (Metropolitan Bilbao, Bay of Biscay, Basque Country). The study was carried out on a set of 116 sediment samples, previously lyophilized and sieved with a particle size lower than 63 microm. Sample reference data were obtained by inductively coupled plasma mass …
Multivariate Frequency Domain Analysis of Causal Interactions in Physiological Time Series
2011
A common way of obtaining information about a physiological system is to measure one or more signals from the system, consider their temporal evolution in the form of numerical time series, and obtain quantitative indexes through the application of time series analysis techniques. While historical approaches to time series analysis were addressed to the study of single signals, recent advances have made it possible to study collectively the behavior of several signals measured simultaneously from the considered system. In fact, multivariate (MV) time series analysis is nowadays extensively used to characterize interdependencies among multiple signals collected from dynamical physiological s…
Accuracy of SCORTEN to predict the prognosis of Stevens‐Johnson syndrome/toxic epidermal necrolysis: a systematic review and meta‐analysis
2019
BACKGROUND The SCORTEN score is a specific predictor of the probability of death for patients diagnosed with Stevens-Johnson syndrome (SJS)/toxic epidermal necrolysis (TEN). OBJECTIVES To evaluate the overall accuracy of SCORTEN and the influence of several moderators such as age, sex, geographical region and age of the study. METHODS A systematic search was performed on MEDLINE, The Cochrane Library, EMBASE, SCOPUS and Web of Knowledge, with no restriction on language (last update 5 February 2019 for all databases). Original studies on the use of SCORTEN were eligible. The standardized mortality ratio (SMR), defined as the quotient between the number of deaths observed and the number expec…
253 PFS of elderly ovarian cancer patients might be predicted by G-8 geriatric screening tool – results of a retrospective cohort study
2021
Introduction/Background* The aim of this study was to evaluate the impact of the preoperative global health status on the prognosis of patients with ovarian cancer (OC) older than 60 years, who received cytoreductive surgery. Methodology G-8 geriatric screening tool (G-8 score), Lee Schonberg prognostic index, Eastern Cooperative Oncology Group (ECOG) performance status and Charlson Comorbidity Index (CCI) were determined retrospectively in a consecutive cohort of elderly patients with OC. Univariate and multivariate Cox regression analyses and Kaplan-Meier method were performed to analyze the impact of the preoperative global health status on survival. Result(s)* 116 patients entered the s…
The Relapsing Polychondritis Disease Activity Index: Development of a disease activity score for relapsing polychondritis.
2012
Abstract Objective The rarity of relapsing polychondritis (RP) has hindered the development of standardized tools for clinical assessment. Here, we describe the development of a preliminary score for disease assessing activity in RP, the Relapsing Polychondritis Disease Activity Index (RPDAI). Methods Twenty-seven RP experts participated in an international collaboration. Selection and definition of items for disease activity were established by consensus during a 4-round internet-based Delphi survey. Twenty-six experts assessed the Physician's Global Assessment (PGA) of disease activity on 43 test cases on a 0–100 scale, yielding a total of 1118 PGA ratings. The weight of each item was est…