Search results for "Multivariate Analysis"
showing 10 items of 1076 documents
A note on (basic) Principal Components Analysis
2020
This paper provides some issues, known but somewhat little stressed, on using the conventional covariance or correlation matrix when performing the simple PCA. The paper also proposes a new simple alternative by providing some evidence, via real-data analysis and some simulation experiments, supporting the proposal
Volcanic products of Lipari (Aeolian islands, Italy): Multivariate analysis of petrographic and radiometric data
2010
Abstract A petrographic and radiometric study, along with statistical multivariate analysis of volcanic products of the island of Lipari (Aeolian islands, Italy) was carried out. The volcanological history of Lipari was reconstructed defining two stages (pre- and post-erosive stages) further on subdivided in four volcanic phases, each of which characterized by products with a particular chemical composition and separated by stratigraphic unconformities. The correlations between petrographic features, determined by X-ray fluorescence, and volcanological history of the island highlight a gradual differentiation with younger rocks showing a more acid chemical composition than the older ones. R…
A new species of Armeria (Plumbaginaceae) from southern Spain with molecular and morphometric evidence on its origin
2001
The definitive version is available at http://onlinelibrary.wiley.com/
The Influence of an Enriched Sport Program on Children’s Sport Motivation in the School Context: The ESA PROGRAM
2020
Purpose: Besides the evident positive effect on body development, physical activity has proven to boost executive functions, especially if the exercises are enriched with cognitive stimuli. Previous studies have shown that introducing challenging exercises in the physical activity routine can also enhance motivation. Therefore, enriching a physical education program with cognitively challenging exercises may also foster children’s motivation during physical education classes, where the motivation is high at the beginning of the school year and low at the end of it. Therefore, the purpose of this paper is to test if a sport program enriched by cognitive stimuli may improve kids’ motivation o…
Multi-elemental EDXRF mapping of polluted soil from former horticultural land.
2004
The distribution of major and trace elements was systematically investigated by use of energy dispersive X-ray fluorescence spectrometry (EDXRF) on a former horticultural soil. The purpose of the study was to combine mapping of soil element concentration levels with multivariate statistics for characterisation of soil metal pollution in relation to previous and present land use. A 1-ha study site was chosen from a former horticulture where a previous preliminary survey indicated increased concentration levels of toxic elements. The soil was sampled from the top 20 cm of the soil surface in a 10×10-m grid-like pattern covering the 1-ha study area. In addition, three soil profiles were studie…
Students’ physical activity intensity and sedentary behaviour by physical self-concept profiles: A latent profile analysis. [Intensidad de la activid…
2020
Abstract Aims of this study were to identify student clusters in physical appearance, sport competence, global physical self-concept and self-esteem, and to examine whether different physical self-concept groups differ in their moderate-to-vigorous physical activity (MVPA) and sedentary behaviour. Participants of the study were 211 boys and 183 girls aged 13-16 years. MVPA and sedentary behaviour were monitored by GT3X accelerometers during seven days. Participants’ physical self-concept was measured by the short Physical Self-Description Questionnaire. Latent profile analyses revealed a four-cluster solution: 1) “low sport competence, moderate global physical self-concept and self-esteem, …
gllvm : Fast analysis of multivariate abundance data with generalized linear latent variable models in R
2019
1.There has been rapid development in tools for multivariate analysis based on fully specified statistical models or “joint models”. One approach attracting a lot of attention is generalized linear latent variable models (GLLVMs). However, software for fitting these models is typically slow and not practical for large datsets. 2.The R package gllvm offers relatively fast methods to fit GLLVMs via maximum likelihood, along with tools for model checking, visualization and inference. 3.The main advantage of the package over other implementations is speed e.g. being two orders of magnitude faster, and capable of handling thousands of response variables. These advances come from using variationa…
Parental and Infant Gender Factors in Parent-Infant Interaction: State-Space Dynamic Analysis.
2017
This study aimed to investigate the influence of parental gender on their interaction with their infants, considering, as well, the role of the infant’s gender. The State Space Grid (SSG) method, a graphical tool based on the non-linear dynamic system (NDS) approach was used to analyze the interaction, in Free-Play setting, of 52 infants, aged 6 to 10 months, divided into two groups: half of the infants interacted with their fathers and half with their mothers. There were 50% boys in each group. MANOVA results showed no differential parenting of boys and girls. Additionally, mothers and fathers showed no differences in the Diversity of behavioral dyadic states nor in Predictability. However…
Heritability of maximal isometric muscle strength in older female twins.
2003
The purpose of the present study was to examine genetic and environmental effects on maximal isometric handgrip, knee extension, and ankle plantar flexion strength. In addition, we wanted to investigate whether the strength of these three muscle groups shares a genetic component or whether the genetic effect is specific for each muscle group. Muscle strength was measured as part of the Finnish Twin Study on Aging in 97 monozygotic (MZ) and 102 dizygotic (DZ) female twin pairs, aged 63-76 yr. The MZ and DZ individuals did not differ from each other in age, body height, weight, or self-related health. The age-adjusted pairwise (intraclass) correlations of the MZ and DZ twins were, respective…
Comprehensive geriatric assessment is an essential tool to support treatment decisions in elderly patients with diffuse large B-cell lymphoma: A pros…
2015
We performed a multicenter study to validate the concept that a simple comprehensive geriatric assessment (CGA) can identify elderly, non-fit patients with diffuse large B-cell lymphoma (DLBCL) in whom curative treatment is not better then palliation, and to analyze potential benefits of treatment modulation after further subdividing the non-fit category by CGA criteria. One hundred and seventy-three patients aged > 69 treated with curative or palliative intent by clinical judgement only were grouped according to CGA into fit (46%), unfit (16%) and frail (38%) categories. Two-year overall survival (OS) was significantly better in fit than in non-fit patients (84% vs. 47%; p < 0.0001).…