Search results for "cluster analysis."

Molecular Surveillance of HIV-1 in Madrid, Spain: a Phylogeographic Analysis ▿

2011

ABSTRACT The molecular epidemiology of HIV-1 is constantly changing, mainly as a result of human migratory flows and the high adaptive ability of the virus. In recent years, Spain has become one of Europe's main destinations for immigrants and one of the western European countries with the highest rates of HIV-positive patients. Using a phylogeographic approach, we have analyzed the relationship between HIV-1 variants detected in immigrant and native populations of the urban area of Madrid. Our project was based on two coincidental facts. First, resistance tests were extended to naïve and newly diagnosed patients, and second, the Spanish government legislated the provision of legal status t…

U-search: a meta engine for creation of knowledge paths on the web

2010

The main tools used to find digital contents in the Web are search engines and directories but they are not presently able to understand the user specific needs and starting knowledge. This work presents "U-Search" a new meta engine that allows to create knowledge paths on the Web based on specific user requirements and knowledge levels. To this end, we consider different searcher categories such as a "basic searcher" who knows little about a topic and will look for more information, a "deep searcher" who will look for specific details on a topic that he/she already knows and a "wide searcher" who will look for expanding his/her knowledge domain with topics that are loosely related to the s…

Clinical support in radiation therapy scenarios: MR brain tumor segmentation using an unsupervised fuzzy C-Means clustering technique

2016

Integrative transnational analysis to dissect tuberculosis transmission events along the migratory route from Africa to Europe

2021

páginas, 4 figuras, 3 tablas

Estradiol Stimulates Vasodilatory and Metabolic Pathways in Cultured Human Endothelial Cells

2009

Vascular effects of estradiol are being investigated because there are controversies among clinical and experimental studies. DNA microarrays were used to investigate global gene expression patterns in cultured human umbilical vein endothelial cells (HUVEC) exposed to 1 nmol/L estradiol for 24 hours. When compared to control, 187 genes were identified as differentially expressed with 1.9-fold change threshold. Supervised principal component analysis and hierarchical cluster analysis revealed the differences between control and estradiol-treated samples. Physiological concentrations of estradiol are sufficient to elicit significant changes in HUVEC gene expression. Notch signaling, actin cyt…

Using Two-Step Cluster Analysis and Latent Class Cluster Analysis to Classify the Cognitive Heterogeneity of Cross-Diagnostic Psychiatric Inpatients

2020

The heterogeneity of cognitive profiles among psychiatric patients has been reported to carry significant clinical information. However, how to best characterize such cognitive heterogeneity is still a matter of debate. Despite being well suited for clinical data, cluster analysis techniques, like the Two-Step and the Latent Class, received little to no attention in the literature. The present study aimed to test the validity of the cluster solutions obtained with Two-Step and Latent Class cluster analysis on the cognitive profile of a cross-diagnostic sample of 387 psychiatric inpatients. Two-Step and Latent Class cluster analysis produced similar and reliable solutions. The overall result…

Principal component analysis and cluster analysis for measuring the local organisation of human atrial fibrillation

2001

The distribution of atrial electrogram types has been proposed to characterise human atrial fibrillation. The aim of this study was to provide computer procedures for evaluating the local organisation of intracardiac recordings during AF as an alternative to off-line manual classification. Principal components analysis (PCA) reduced the data set to a few representative activations, and cluster analysis (CA) measured the average dissimilarity between consecutive activations of an intracardiac signal. The data set consisted of 106 bipolar signals recorded on 11 patients during electrophysiological studies for catheter ablation. Performances of PCA and CA in distinguishing between organised (t…

Walking Stroop carpet: an innovative dual-task concept for detecting cognitive impairment

2013

A Perrochon,1,2,5 G Kemoun,1,2 E Watelain,3,4 A Berthoz51ISIS, Research Institute on Handicap and Aging, Paris; 2Université de Poitiers, Laboratoire Mobilité, Vieillissement et Exercice (MOVE), EA 6314, 3Université de Valenciennes, LAMIH, UMR CNRS 8201, 4Université Sud Toulon Var, HandiBio, EA 4322, La Garde, 5LPPA, UMR CNRS 7152, Collège de France, Paris, FranceBackground: Several studies have reported the potential value of the dual-task concept during locomotion in clinical evaluation because cognitive decline is strongly associated with gait abnormalities. However, current dual-task tests appear to be insufficient for early diagnosi…

Conditional predictive inference for online surveillance of spatial disease incidence

2011

This paper deals with the development of statistical methodology for timely detection of incident disease clusters in space and time. The increasing availability of data on both the time and the location of events enables the construction of multivariate surveillance techniques, which may enhance the ability to detect localized clusters of disease relative to the surveillance of the overall count of disease cases across the entire study region. We introduce the surveillance conditional predictive ordinate as a general Bayesian model-based surveillance technique that allows us to detect small areas of increased disease incidence when spatial data are available. To address the problem of mult…

Pain and clinical findings in the low back: a study of industrial employees with 5-, 10-, and 28-year follow-ups.

2009

Little is known about the relationships of clinical findings in the low back with low back pain (LBP) in the normal working population. We studied whether physiotherapist's findings in the low back were associated with local and radiating LBP among a cohort (n=902) of employees in the engineering industry. A systematic non-proportional sample was drawn in strata by age, gender, and occupational class. The non-proportionality aimed at increasing sample size in smaller strata. Physiotherapists performed the straight-leg raising test (SRL), and made assessments of the fingertip-to-floor distance and pain in palpation of the lumbar interspinous spaces. The variables on pain at the interspinous …