Search results for "Statistical"
showing 10 items of 4960 documents
Relations between multi-resolution analysis and quantum mechanics
2005
We discuss a procedure to construct multiresolution analyses (MRA) of L2 (R) starting from a given seed function h (s) which should satisfy some conditions. Our method, originally related to the quantum mechanical Hamiltonian of the fractional quantum Hall effect, is shown to be model independent. The role of a canonical map between certain canonically conjugate operators is discussed. This clarifies our previous procedure and makes much easier most of the original formulas, producing a convenient framework to produce examples of MRA. © 2005 American Institute of Physics.
Varietal and geographic classification of french red wines in terms of major acids
1989
Concentrations of acids other than malic and lactic appeared to be related more to area of production than to grape variety. These variables (2- hydroxyglutaric, butyric and isovaleric acid concentrations) were attributed to differences in the technological process used for vinification in the various areas. Shikimic and galacturonic acids were helpful for classifying and discriminating wine varieties. Principal component analysis characterised Cabernet Franc, Grenache and Carignan wines well by their acid content but failed to discriminate Merlot from Cabernet Sauvignon and Cinsault. Stepwise discriminant analysis allowed a clear separation of all wines according to the different varieties…
1H NMR Spectroscopy with Multivariate Statistical Analysis as a Tool for a Rapid Screening of the Molecular Changes Occurring During Micro-Oxygenatio…
2008
A red wine from Aglianico vine was subjected to a micro-oxygenation procedure for five weeks. The wine was weekly sampled together with a non micro-oxygenated control and extracted with di-ethyl-ether in order to simplify NMR analyses. In fact, 1 H NMR spectra of the whole wine samples were dominated by water and ethanol signals which pre- vented visibility of the resonances generated by the less concentrated wine components. The 1 H NMR analyses of the di- ethyl-ether extracts revealed an increase of the amount of oxygen-containing materials. Such increase was attributed to a wine ageing process which resulted, hence, fastened by application of micro-oxygenation.
Expressing forest origins in the chemical composition of cooperage oak woods and corresponding wines by using FTICR-MS.
2008
A non-targeted, ultra-high-resolution mass spectrometric, direct analysis of oak-wood extracts from two species (Quercus robur L. and Quercus petraea Liebl.) from three French forests, and of a wine aged in barrels derived therefrom has been performed to identify families of metabolites that could discriminate both the species and the geographical origin of woods. From 12 T ultra-high-resolution Fourier transform ion cyclotron resonance mass spectra of wood extracts, hundreds of mass signals were identified as possible significant biomarkers of the two species, with phenolic and carbohydrate moieties leading the differentiation between Q. robur and Q. petraea, respectively, as corroborated …
Multivariate Methods Based Soft Measurement for Wine Quality Evaluation
2014
Published version of an article in the journal: Abstract and Applied Analysis. Also available from the publisher at: http://dx.doi.org/10.1155/2014/740754 Open Access Soft measurement is a new, developing, and promising industry technology and has been widely used in the industry nowadays. This technology plays a significant role especially in the case where some key variables are difficult to be measured by traditional measurement methods. In this paper, the quality of the wine is evaluated given the wine physicochemical indexes according to multivariate methods based soft measurement. The multivariate methods used in this paper include ordinary least squares regression (OLSR), principal c…
The chemodiversity of wines can reveal a metabologeography expression of cooperage oak wood
2009
Wine chemical compositions, which result from a complex interplay between environmental factors, genetic factors, and viticultural practices, have mostly been studied using targeted analyses of selected families of metabolites. Detailed studies have particularly concerned volatile and polyphenolic compounds because of their acknowledged roles in the organoleptic and therapeutic properties. However, we show that an unprecedented chemical diversity of wine composition can be unraveled through a nontargeted approach by ultrahigh-resolution mass spectrometry, which provides an instantaneous image of complex interacting processes, not easily or possibly resolvable into their unambiguous individu…
A grape and wine chemodiversity comparison of different appellations in Burgundy: vintage vs terroir effects.
2013
Abstract This study aimed at assessing the ability of high resolution Fourier Transform Ion Cyclotron Resonance – Mass Spectrometry (FTICR–MS) to differentiate grapes and corresponding wines from distinct vineyards managed by a same producer, according to complex chemical fingerprints. Grape extracts (at harvest) and corresponding wines from four different vineyards, sampled immediately after the alcoholic fermentation over three successive vintages, were analysed by FTICR–MS. Thousands of metabolites that are specific to a given vintage, or a given class (wine, skin or must) could be revealed, thus emphasising a strong vintage effect. The same wines were reanalyzed after a few years in bot…
High precision mass measurements for wine metabolomics
2014
An overview of the critical steps for the non-targeted Ultra-High Performance Liquid Chromatography coupled with Quadrupole Time-of-Flight Mass Spectrometry (UPLC-Q-ToF-MS) analysis of wine chemistry is given, ranging from the study design, data preprocessing and statistical analyses, to markers identification. UPLC-Q-ToF-MS data was enhanced by the alignment of exact mass data from FTICR-MS, and marker peaks were identified using UPLC-Q-ToF-MS(2). In combination with multivariate statistical tools and the annotation of peaks with metabolites from relevant databases, this analytical process provides a fine description of the chemical complexity of wines, as exemplified in the case of red (P…
La cultura ci salverà? Processi di touristification a base culturale nel centro storico di Palermo
2023
Negli ultimi tre decenni la cultura ha avuto un ruolo chiave nella costruzione delle politiche urbane, divenendo uno strumento decisivo nella definizione delle strategie di sviluppo economico e nell’accesso alla competizione globale che caratterizzano l’attuale regime di neoliberismo urbano (Miles e Paddison 2005). Anche nel sud Europa la cosiddetta rigenerazione a base culturale ha rappresentato e continua ancora oggi a rappresentare una vera e propria ortodossia urbana, che trova nel turismo tanto una ragione di esistenza quanto un campo di attuazione. In particolare, negli ultimi anni i centri storici di molte città sudeuropee sono stati oggetto di trasformazioni profonde in cui pratiche…
Overdispersion tests in count-data analysis.
2008
Count data are commonly assumed to have a Poisson distribution, especially when there is no diagnostic procedure for checking this assumption. However, count data rarely fit the restrictive assumptions of the Poisson distribution. The violation of much of such assumptions commonly results in overdispersion, which invalidates the Poisson distribution. Undetected overdispersion may entail important misleading inferences, so its detection is essential. In this study, different overdispersion diagnostic tests are evaluated through two simulation studies. In Exp. 1, the nominal error rate is compared under different sample sizes and Λ conditions. Analysis shows a remarkable performance of the χ…