Search results for "multivariate statistic"
showing 10 items of 327 documents
Logit analysis in L2 research: measuring L1 and L2/Ln effects
1998
In quantitatively oriented L2 studies, we normally contrast two phenomena at a time, both at the group and individual level. However, it is generally acknowledged that what a learner produces is determined by a multitude of factors influencing the interlanguage (IL) simultaneously. When dealing with discrete, nominal categories, the numerical and causal relations between the variables involved cannot be adequately captured in an analysis where the phenomenon to be studied and the explanatory factors are subjected to a series of pairwise statistical tests. Instead of the two-variable approach, multivariate techniques should be applied, since they allow for the examination of the effects of m…
Organizational Cooperation and Knowledge Management in Research and Development Organizations
2017
Organizational Cooperation (OC) is a current concept that responds to the growing interdependence among individuals and teams. Likewise, Knowledge Management (KM) accompanies specialization in all sectors of human activity. Most KM processes are cooperation-intensive, and the way both constructs relate to each other is relevant in understanding organizations and promoting performance. The present paper focuses on that relationship. The Organizational Cooperation Questionnaire (ORCOQ) and the Short form of the Knowledge Management Questionnaire (KMQ-SF) were applied to 639 members of research and development (R&D) organizations (Universities and Research Institutes). Descriptive, correla…
Hypoxia and hypothermia as rival agents of selection driving the evolution of viviparity in lizards
2017
[Aim]: The evolution of key innovations promotes adaptive radiations by opening access to new ecological opportunity. The acquisition of viviparity (live-bearing reproduction) has emerged as one such innovation explaining reptile proliferations into extreme climates. By evolving viviparity, females provide embryos with internally stable environments to complete development. The classical hypothesis suggests that natural selection for viviparity arises from low temperatures in cold climates, which promote prolonged egg retention in the mother's body. An alternative hypothesis proposes that declines in atmospheric oxygen at high elevations create natural selection for embryo retention to prov…
Relationship between Fertility Traits and Kinematics in Clusters of Boar Ejaculates
2021
The aim was to determine the relationship between kinematic parameters of boar spermatozoa and fertility rates of sow, as well as to assess the effect of sperm clusters on the fertility capacity of the ejaculate. Semen samples were collected from 11 sexually mature boars. Samples were analyzed by an ISAS®v1 CASA-Mot system for eight kinematic parameters. Ejaculate clusters were characterized using multivariate procedures, such as principal factors (PFs) analysis and clustering methods (the k-means model). Four different ejaculate clusters were identified from two kinematic PFs which involved linear trajectory and velocity. There were differences (p 0.05) between dam lines and ejaculate clus…
FISCAL READJUSTMENTS IN THE UNITED STATES: A NONLINEAR TIME-SERIES ANALYSIS
2009
We analyze the fiscal adjustment process in the United States using a multivariate threshold vector error regression model. The shift from single-equation to multivariate setting adds value both in terms of our economic understanding of the fiscal adjustment process and the forecasting performance of nonlinear models. We find evidence that fiscal authorities intervene to reduce real per capita deficit only when it reaches a certain threshold and that fiscal adjustment takes place primarily by cutting government expenditure. The results of out-of-sample density forecast and probability forecasts suggest that a shift from a univariate autoregressive model to a multivariate model improves fore…
Spermiogram and sperm head morphometry assessed by multivariate cluster analysis results during adolescence (12-18 years) and the effect of varicocele
2016
Artículo científico This work evaluates sperm head morphometric characteristics in adolescents from 12 to 18 years of age, and the effect of varicocele. Volunteers between 150 and 224 months of age (mean 191, n = 87), who had reached oigarche by 12 years old, were recruited in the area of Barranquilla, Colombia. Morphometric analysis of sperm heads was performed with principal component (PC) and discriminant analysis. Combining seminal fluid and sperm parameters provided five PCs: two related to sperm morphometry, one to sperm motility, and two to seminal fluid components. Discriminant analysis on the morphometric results of varicocele and nonvaricocele groups did not provide a useful class…
Psychological and physical dimensions explaining life satisfaction among the elderly: A structural model examination
2007
The aim of the present paper is to analyze the effects of psychological well-being, physical functioning and socio-demographic factors on life satisfaction. Both a bivariate and a multivariate level of analyses have been used. Finally, a structural model explaining life satisfaction has been developed and validated. With respect to bivariate relations, there was evidence of significant positive relations between psychological well-being dimensions and life satisfaction and between physical conditions and life satisfaction as well. Also, as age increased there was a slow decrease in life satisfaction. Educational level was positively related to life satisfaction. A structural model gave valu…
Levels of trace elements in human hair samples of adolescents living near petrochemical plants
2020
The aim of the study is a comparative analysis to investigate human hair metal profiles of adolescents residing near petrochemical plants (Sicily, Italy). We selected the small town of Augusta, Gela, and Pace del Mela, and a control area made up of the towns characterized by low anthropogenic activity. Twenty trace elements were measured in samples of scalp hair from adolescents (11–14 years old) of both genders. Hair samples were cleaned using a rigorous cleaning method, mineralized, and processed for analyses by inductively coupled plasma–mass spectrometry (ICP-MS). In industrial sites, zinc was always the most abundant element, ranging from186 to 217 μg g−1. Following zinc, the elements …
The predictive value of exercise testing for survival among 75-year-old men and women
2006
All 75-year-olds born in 1914 and living in the city of Jyväskylä, central Finland (n=388) were invited to study the predictive value of exercise test for mortality. Subjects who entered the laboratory (n=295) were to have a standard pre-test evaluation and perform a cycle ergometer exercise test. Subjects with complete background, exercise-test status and mortality data (n=282) were divided into three groups according to exercise-test status: a non-exercise test group (n=79), an exercise-test termination group (n=95), and an exercise-test completion group (n=108). Mortality was followed up for 9 years. The multivariate hazard ratio (HR) for death among the non-exercise test group compared …
Development and validation of the FRAGIRE tool for assessment an older person’s risk for frailty
2016
International audience; Background: Frailty is highly prevalent in elderly people. While significant progress has been made to understand its pathogenesis process, few validated questionnaire exist to assess the multidimensional concept of frailty and to detect people frail or at risk to become frail. The objectives of this study were to construct and validate a new frailty-screening instrument named Frailty Groupe Iso-Ressource Evaluation (FRAGIRE) that accurately predicts the risk for frailty in older adults.Methods: A prospective multicenter recruitment of the elderly patients was undertaken in France. The subjects were classified into financially-helped group (FH, with financial assista…