Search results for "Multivariate analysis"

TESTING SIMILARITY COEFFICIENTS FOR ANALYSIS OF THE FOSSIL RECORD USING CLUSTERING METHODS: THE PALAEOZOIC FLORA AS A STUDY CASE

2020

This paper reports a global methodological approach based on the similarity and clustering methods of the Palaeozoic plant fossil record using a comparative approach between two similarity measures: the Jacard and Raup-Crick Coefficients. The results show that although the Raup-Crick Coefficients clearly have the potential for providing more robust results, the consequences of the extinction processes are better reflected in the similarity analysis based on the Jaccard Coefficients. On the other hand, the cluster analysis based on UPGMA algorithm shows four robust clusters and reveals new evidence for the singularity of Mississippian flora. Finally, the results obtained reveal that similari…

Flood frequency analysis for an urban watershed: comparison between several statistical methodologies simulating synthetic rainfall events

2016

To obtain the flooding frequency distribution for an urban watershed, different methods based on simulations of synthetic rainfall events were compared with an empirical analysis of the flooding data and with the results of long-term simulations. A copula-based multivariate statistical analysis of the main hydrological variables was proposed to generate synthetic hyetographs. Two different approaches were adopted to assess a temporal pattern to the synthetic rainfall: one analyses all available historical rainfall patterns, and another adopts the cluster analysis in three different variants to reduce the computational effort of the analysis. To test the methodology reliability, the analysis…

Liver Imaging Reporting and Data System (LI-RADS) v2018: diagnostic value of ancillary features favoring malignancy in hypervascular observations ≥ 1…

2020

This study was conducted in order to assess the diagnostic accuracy of LI-RADS v2018 ancillary features (AFs) favoring malignancy applied to LR-3 and LR-4 observations on gadoxetate-enhanced MRI. In this retrospective dual-institution study, we included consecutive patients at high risk for hepatocellular carcinoma (HCC) imaged with gadoxetate disodium-enhanced MRI between 2009 and 2014 fulfilling the following criteria: (i) at least one LR-3 or LR-4 observation ≥ 10 mm; (ii) nonrim arterial phase hyperenhancement; and (iii) confirmation of benignity or malignancy by pathology or imaging follow-up. We compared the distribution of AFs between HCCs and benign observations and the diagnostic p…

Are virtues national, supranational, or universal?

2014

Many studies investigated cultural differences in values, most notably by Hofstede and Schwarz. Relatively few have focused on virtues, a related and important concept in contemporary social science. The present paper examines the similarities and differences between nations, or blocks of - culturally related - nations on the perceived importance of virtues. Adults (N = 2.809 students) from 14 countries were asked to freely mention which virtues they found important to practice in daily life, and next to rate a list of 15 virtues, which reflect the most frequently mentioned categories in The Netherlands, as found in a previous study. The 14 nations included the United States, Mexico, nine E…

Mediterranean diet adherence and synergy with acute myocardial infarction and its determinants: A multicenter case-control study in Italy

2018

Background Cardiovascular diseases are the leading causes of mortality and morbidity in Western countries. The possible synergistic effect of poor adherence to a Mediterranean diet (MD) and other risk factors for acute myocardial infarction (AMI) such as hypertension, cholesterol, ever smoker, BMI> 25, diabetes, has not been deeply studied. Design Case-control study. Methods Patients with first AMI and controls from four tertiary referral Italian centers were screened for enrolment. Dietary information was collected through a questionnaire and a MD adherence score was calculated. Physical activity and smoking habits were also registered. The Synergy Index was calculated according to Rothman…

Factors associated with first- versus second-generation long-acting antipsychotics prescribed under ordinary clinical practice in Italy

2018

Background For many years, long-acting intramuscular (LAI) antipsychotics have been prescribed predominantly to chronic and severe patients, as a last resort when other treatments failed. Recently, a broader and earlier use of LAIs, particularly second-generation LAIs, has been emphasized. To date, few studies attempted to frame how this change in prescribing took place in real-world practice. Therefore, this study aimed to describe the clinical features of patients prescribed with LAIs, and to explore possible prescribing differences between first- and second-generations LAIs under ordinary clinical practice in Italy. Methods The STAR Network "Depot" Study is an observational, longitudinal…

Is group selection a factor modulating the virulence of RNA viruses?

1997

RNA viruses consist of populations of extremely high genetic heterogeneity called quasispecies. Based on theoretical considerations, it has been suggested that the unit of selection in such complex genetic populations is not the single viral particle but a set of genetically related particles which form the quasispecies. In the present study we carried out a set of experiments with the vesicular stomatitis virus (VSV) dealing with the evolution of life-history characters under selection acting at two factors either in the same or in opposite directions. The two factors at which selective pressure is applied are the individual and the group. We show evidence that group selection modulates th…

2016

Vaccination of the elderly is an important factor in limiting the impact of influenza in the community. The aim of this study was to investigate the factors associated with influenza vaccination coverage in hospitalized patients aged ≥65 years hospitalized due to causes unrelated to influenza in Spain. We carried out a cross-sectional study. Bivariate analysis was performed comparing vaccinated and unvaccinated patients, taking in to account sociodemographic variables and medical risk conditions. Multivariate analysis was performed using multilevel regression models. We included 1038 patients: 602 (58%) had received the influenza vaccine in the 2013–14 season. Three or more general practiti…

Predictor variables for a half marathon race time in recreational male runners

2011

Christoph Alexander Rüst1, Beat Knechtle1,2, Patrizia Knechtle2, Ursula Barandun1, Romuald Lepers3, Thomas Rosemann11Institute of General Practice and Health Services Research, University of Zurich, Zurich, Switzerland; 2Gesundheitszentrum St Gallen, St Gallen, Switzerland; 3INSERM U887, University of Burgundy, Faculty of Sport Sciences, Dijon, FranceAbstract: The aim of this study was to investigate predictor variables of anthropometry, training, and previous experience in order to predict a half marathon race time for future novice recreational male half marathoners. Eighty-four male finishers in the ‘Half Marathon Basel’ completed the race distance within (me…

Gender, exercise, and health: A life-course cross-sectional study.

2020

The purpose of this study is to explore relationships between the practice of exercise, gender, and health, from adolescence to old age, testing the magnitude of gender differences throughout the life cycle in the practice of exercise of Spanish people. A cross-sectional study with 4,575 women and 4,334 men, aged 13-85 years, was conducted. The participants were assessed on the weekly hours they dedicated to the practice of exercise, masculine/instrumental and feminine/expressive traits, mental health symptomatology, and self-rated health). Univariate and multivariate analyses were performed in the age groups of adolescence, late adolescence, young adulthood, middle adulthood, and older age…