Search results for "Multivariate statistical"
showing 10 items of 44 documents
Multivariate statistical analysis of a large odorants database aimed at revealing similarities and links between odorants and odors
2017
International audience; The perception of odor is an important component of smell; the first step of odor detection, and the discrimination of structurally diverse odorants depends on their interactions with olfactory receptors (ORs). Indeed, the perception of an odor's quality results from a combinatorial coding, in which the deciphering remains a major challenge. Several studies have successfully established links between odors and odorants by categorizing and classifying data. Hence, the categorization of odors appears to be a promising way to manage odors. In the proposed study, we performed a computational analysis using odor descriptions of the odorants present in Flavor-Base 9th Edit…
Unexpected high frequency of genital involvement in women with clinical and hostological features of oral lichen planus
2006
The main aims of this cross-sectional study were: (i) to assess the frequency of genital (vulval) lichen planus (VLP) and vulval lichen sclerosus (VLS) in women affected with oral lichen planus (OLP), regardless of the genital symptoms reported; and (ii) to verify whether any demographic, clinical, or histological features of OLP are associated with a higher risk of vulvo-vaginal involvement. Fifty-five women, presenting OLP, consecutively underwent gynaecological examination and, if they demonstrated positive clinical signs of VLP, underwent biopsy. After a drop-out of 14 subjects, 31/41 (75.6%) were found to have signs of genital involvement, of which 13/31 (44.0%) were asymptomatic. Foll…
Chemical and Microbiological Characterization for PDO Labelling of Typical East Piedmont (Italy) Salami
2015
This study is focused on the characterisation of typical salami produced in Alessandria province (North West of Italy). Seventeen small or medium salami producers from this area were involved in the study and provided the samples investigated. The aim is double and consists in obtaining a screening of the characteristics of different products and following their evolution along ripening. The study involved five types of typical salami that were characterised for aroma components and nutritional features. This approach could provide a basis for a possible PDO or PGI label request. Principal Component Analysis and cluster analysis were used as multivariate statistical tools for data treatment…
Biogenic Selenium Nanoparticles: A Fine Characterization to Unveil Their Thermodynamic Stability
2021
Among the plethora of available metal(loid) nanomaterials (NMs), those containing selenium are interesting from an applicative perspective, due to their high biocompatibility. Microorganisms capable of coping with toxic Se-oxyanions generate mostly Se nanoparticles (SeNPs), representing an ideal and green alternative over the chemogenic synthesis to obtain thermodynamically stable NMs. However, their structural characterization, in terms of biomolecules and interactions stabilizing the biogenic colloidal solution, is still a black hole that impairs the exploitation of biogenic SeNP full potential. Here, spherical and thermodynamically stable SeNPs were produced by a metal(loid) tolerant Mic…
Multivariate quality control studies applied to Ca(II) and Mg(II) determination by a portable method
1998
Made available in DSpace on 2022-04-28T19:53:14Z (GMT). No. of bitstreams: 0 Previous issue date: 1998-01-01 A portable or field test method for simultaneous spectrophotometric determination of calcium and magnesium in water using multivariate partial least squares (PLS) calibration methods is proposed. The method is based on the reaction between the analytes and methylthymol blue at pH 11. The spectral information was used as the X-block and the Ca(II) and Mg(II) concentrations obtained by a reference technique (ICP-AES) were used as the Y-block. Two series of analyses were performed, with a month's difference between them. The first series was used as the calibration set and the second on…
Predictive value of morphologic parameters for successful correction of Class II Division 2 malocclusion
2003
Abstract The aim of this study was to assess the predictive value of pretreatment cephalometric parameters and apical base size for successful correction of Angle Class II Division 2 malocclusion. Pretreatment lateral cephalograms and pretreatment and posttreatment study casts of 96 subjects with Class II Division 2 malocclusions were examined to obtain 23 cephalometric parameters and to measure the size of the apical bases. Success of occlusal correction was evaluated as the percentage of change of peer assessment rating scores during treatment; percentage of change was the dependent variable in multivariate statistical analyses used to test the predictive value of the assessed parameters.…
Archaeometry of Sicilian glazed pottery
2004
Petrographic and chemical analyses of the “ceramic body” of 114 majolica artefacts manufactured in Sicily over a wide time range (16th–-19th century) are presented. All the analysed samples, which belong to museums and private collections, were previously attributed to Sicilian workshops based on stylistic features evaluated by expert historians of art. Unambiguous identification of the production sites of majolica handicrafts in Sicily remains, however, open to question when this relies only on purely stylistic considerations. To this end compositional and/or textural markers have been searched for in the “ceramic body” of the majolica artefacts in order to differentiate between the centre…
Identification of compounds responsible for the odorant properties of aromatic caramel
2012
Aromatic caramel results from the heat treatment of sugars under specific temperature conditions. Because of its richness in aroma compounds and its pleasant organoleptic properties, caramel is widely used in the food industry. However, the composition of the volatile odorant fraction has not been completely elucidated. The aim of this work was thus to identify the volatile odorant compounds responsible for caramel sensory properties using a multivariate statistical technique. Four aromatic caramels differing in terms of their carbohydrate composition and cooking process were chosen. Odorant compounds were screened by gas chromatography–olfactometry (GC-O) and identified by GC–mass spectrom…
Multivariate statistical technique over QoS variables to analyze video quality metrics on IEEE 802.11ac networks
2017
[EN] We present the results from a measurementbasedperformance evaluation of wireless networks basedon IEEE 802.11ac standard in an indoor environment, withthe aim to analyze their performance under high definitionstreaming video applications. We focus our study on analyzingthe highest performance of these standards using off-theshelfequipment as well as the behavior of Quality of Servicevariables and how they affect to the video quality. Thus, wehave analyzed and measured these variables and have applieda multivariate statistical technique, called Factor Analysis,and finally discuss their behavior.
Biometric analysis of Brachionus plicatilis ecotypes from Spanish lagoons
1983
Univariate comparisons and several multivariate statistical analyses have been performed to study the morphometric variability of B. plicatilis. Both laboratory clones kept under constant conditions and natural populations from different Spanish lagoons and different times of the year have been compared. The results show that not only size, but also allometric coefficients are influenced by environmental factors. However, an important genetic component in the variation of shape and size has been visualized. A clear North-South ordination of the populations of the different lagoons and an important dispersion between their summer populations as well as great differences due to seasonal varia…