Search results for "correspondence analysis"
showing 10 items of 53 documents
Combined effect of different factors on weight status and cardiometabolic risk in Italian adolescents
2019
Background The observed increase in body weight and cardiometabolic risk (CR) in youth from developed countries contributes to the global burden of chronic diseases in adult age. The aim of this work is to provide a patterning of the associations between different factors and the weight status and CR of the subjects involved in the Italian ministerial ASSO project. Methods This study involved 919 students from high schools in Palermo. Weight, height and waist circumference were collected by trained teachers; weight status was estimated by the BMI cut-offs for adolescents and CR through the waist-to-height ratio. Questionnaires were administered through the web-based ASSO-NutFit software. Ch…
Effects of environmental and spatial variables on lotic ostracod metacommunity structure in the Iberian Peninsula
2015
The heterogeneous distribution of aquatic species in lotic environments has been studied little in terms of metacommunity theory. Previous empirical tests have found significant spatial and environmental effects in pond and lake communities, but this has not yet been clearly established for stream networks. We conducted a multi-season survey of mountain streams in the Iberian Peninsula. We recorded GIS and in situ environmental data and collected biological samples to determine ostracods and macroinvertebrates and identified 41 ostracod species, the most common belonging to genera Herpetocypris , Sarscypridopsis , and Ilyocypris . A generalized linear model analysis showed that thermal rang…
An extended Benthic Quality Index for assessment of lake profundal macroinvertebrates: addition of indicator taxa by multivariate ordination and weig…
2014
AbstractThe chironomid Benthic Quality Index (BQI) is a widely used metric in assessments of lake status. The BQI is based on 7 indicator taxa, which like most profundal fauna, often occur sporadically in low densities. Hence, a major weakness of the index is that it cannot be calculated when indicator taxa are not captured. Thus, an extension of the BQI that incorporates more macroinvertebrate taxa is desirable. We used 2 statistical approaches (Detrended Correspondence Analysis and Weighted Averaging) to estimate new benthic quality indicator scores for profundal macroinvertebrate taxa and to construct modified BQIs called Profundal Invertebrate Community Metrics (PICMs). We calibrated th…
Subfossil chironomid assemblages in deep, stratified European lakes: relationships with temperature, trophic state and oxygen
2010
Summary 1. The distributions of subfossil remains of chironomid larvae in 28 large, deep and stratified lakes in Europe were examined in surface sediments along a latitudinal transect ranging from northern Sweden to southern Italy. 2. Canonical correspondence analysis (CCA) showed that summer surface water and July air temperature, as well as total phosphorus (TP) concentrations, hypolimnetic oxygen availability and conductivity were statistically significant (P < 0.05) explanatory variables explaining between 11 and 14% of the variance in the chironomid data. 3. Owing to the spatial scale covered by our study, many environmental variables were covarying. Temperature, TP concentration and o…
Distribution and habitat selection of wintering birds in urban environments
1998
Habitat selection of wintering land-birds was studied in 31 human settlements in Finland. A total of 26 wintering bird species representing 5155 individuals were observed. Between-year variation (CVB%) and short-term fluctuation within one winter (CVW%) in species richness (CVB=10% CVW=15%) were low, as were total numbers of birds (CVB=22% CVW=24%) and populations of the most common bird species (CVB=20–40% CVW=15–47%). The most abundant bird species (e.g., Passer domesticus, Parus major and Pica pica) occurred in most of the study sites. The total densities of omnivorous birds, sedentary birds and bird species that commonly use feeding tables were higher in a heavily urbanized areas than i…
Revista electrónica de investigación y evaluación educativa
2016
Este estudio evalúa un procedimiento nuevo para el análisis “micro-sociométrico” de los patrones relacionales de género en el alumnado adolescente, lo que se analiza aplicando Análisis de Correspondencias Múltiples (ACM). El propósito del estudio es desarrollar y validar la Escala de Preferencias Relacionales de Género (EPRG), con el fin de obtener datos válidos y fiables que permitan reconocer la predisposición de las chicas y los chicos adolescentes a relacionarse con sus iguales; y, si las relaciones que establecen están condicionadas por la socialización diferencial de género que propone el patriarcado (Bosch, Ferrer & Alzamora, 2006; Lagarde, 1996; Lomas, 2007; Lorente, 2007; Rodríguez…
Spectral properties of correlation matrices for some hierarchically nested factor models
2007
We show that spectral methods, such as Principal Component Analysis and Random Matrix Theory, are unable to reveal the hierarchical (or nested) structure of a set of mutivariate data. We consider the method introduced in M. Tumminello et al., EPL 78, 30006 (2007) to associate a hierarchical factor model with a set of data by making use of clustering algorithms. This is done by proving the existence of a bijective correspondence between a hierarchical tree and a factor model.
Study of growth opportunities for Sicilian sparkling wine market by a Simple Correspondence Analysis and a Focus Group
2010
Sicilian territory vocation to the production of wines is a prerequisite needed to ensure a large variety of high quality products, very appreciated by national and international markets. Indeed, Sicily produces sparkling wines since the past century and now there are 21 Sicilian wineries that produce high quality sparkling wines. Currently, Sicilian sparkling wines are sold in the local market, however, customer penetration is still low due to a lack of communication and advertising. This paper is divided in two parts and aims to investigate through an experimental survey, possible growth opportunities for Sicilian sparkling wines market. In the rst part we applied the Simple Correspondenc…
Socio-Demographic Vulnerability: The Condition of Italian Young People
2009
For a kind of inertia effect, today the Italian welfare state protects the older too much and, on the contrary, it does not counter sufficiently the new risks associated with other phases of life. Not much seems to be implemented in favour of Italian young people who, as a matter of fact, seem to suffer a lot from the present changes: young people remain longer in the parental home and postpone setting up their own independent life to a most advanced age. In order to understand the situation of vulnerability increasingly widespread among young people, it seemed more and more necessary an in-depth analysis of the reasons and the subjective status of the discomfort that affects young people b…
Measuring Tourist Satisfaction Through a Dual Approach: The 4Q Methodology
2018
Tourist satisfaction is one of the key factors in determining the success of a tourist destination, since it affects behavioural intentions, such as the willingness to revisit and recommend the destination. Therefore, much research has addressed the measuring of tourist satisfaction, either eliciting positive or negative evaluations of a holiday or destination. The spread between expected positive and negative characteristics can trigger a tourist experience. And the gap between expectations and perceptions will produce a feeling of satisfaction or dissatisfaction (Expectancy-Disconfirmation Paradigm, EDP). Under these conditions, this paper adopts a dual approach, considering tourist satis…