Search results for "Variable"
showing 10 items of 1674 documents
Clinical retrospective study of dental implant removal : do patients who require implant removal desire implant prosthesis again?
2020
Background This study investigated the causes of dental implant removal due to complications, and examined whether patients who had dental implant removal desired re-implant prosthesis treatments. Material and Methods A retrospective case–control study was conducted on patients who had their dental implants removed. We investigated whether the removed dental implant was replaced with other implant prostheses. Age, sex, diabetes, smoking, implant site distribution, reason for implant removal, and blade and root-form implants were categorized as predictive variables. The outcome variable was desire for re-implantation or use of other prosthetic methods after implant removal. A logistic regres…
Max–min dispersion with capacity and cost for a practical location problem
2022
Diversity and dispersion problems deal with selecting a subset of elements from a given set in such a way that their diversity is maximized. This study considers a practical location problem recently proposed in the context of max–min dispersion models. It is called the generalized dispersion problem, and it models realistic applications by introducing capacity and cost constraints. We propose two effective linear formulations for this problem, and develop a hybrid metaheuristic algorithm based on the variable neighborhood search methodology, to solve real instances. Extensive numerical computational experiments are performed to compare our hybrid metaheuristic with the state-of-art heurist…
Uniformization of two-dimensional metric surfaces
2014
We establish uniformization results for metric spaces that are homeomorphic to the Euclidean plane or sphere and have locally finite Hausdorff 2-measure. Applying the geometric definition of quasiconformality, we give a necessary and sufficient condition for such spaces to be QC equivalent to the Euclidean plane, disk, or sphere. Moreover, we show that if such a QC parametrization exists, then the dilatation can be bounded by 2. As an application, we show that the Euclidean upper bound for measures of balls is a sufficient condition for the existence of a 2-QC parametrization. This result gives a new approach to the Bonk-Kleiner theorem on parametrizations of Ahlfors 2-regular spheres by qu…
Ecologists overestimate the importance of predictor variables in model averaging: a plea for cautious interpretations.
2014
Abstract: Information-theory procedures are powerful tools for multimodel inference and are now standard methods in ecology. When performing model averaging on a given set of models, the importance of a predictor variable is commonly estimated by summing the weights of models where the variable appears, the so-called sum of weights (SW). However, SWs have received little methodological attention and are frequently misinterpreted. We assessed the reliability of SW by performing model selection and averaging on simulated data sets including variables strongly and weakly correlated to the response variable and a variable unrelated to the response. Our aim was to investigate how useful SWs are …
Motivación y aprendizaje escolar en la Educación Secundaria Obligatoria: Un estudio empírico desde el Modelo de Calidad de Situación Educativa
2015
La desmotivación de los alumnos/as es uno de los principales problemas con los que se enfrenta actualmente el profesorado, sobre todo en los niveles de educación secundaria. Basándonos en el Modelo de Calidad de Situación Educativa (MCSE) (Doménech, 2006, 2007, 2011a, 2011b, 2012, 2013 y Doménech-Betoret, Gómez-Artiga y Lloret-Segura, 2014), este estudio, compuesto de cuatro investigaciones independientes, examina a) cómo se genera la motivación de los alumnos/as de secundaria y cómo ésta va evolucionando a lo largo del curso en función de sus variables personales y de la percepción que éstos se formen del contexto de la situación educativa. Además, b) examina de forma simultánea el efecto …
Interactions, spillovers de connaissance et croissance des économies modernes. Faut-il préférer la globalisation ou la proximité géographique ?
2009
Globalisation and metropolisation in modern economies induce some locational strategies of knowledge based activities towards cities and deeply increase trade and move of ideas across cities. In that context, we study the way knowledge spillovers have influenced the economic growth of 82 European Metropolises over the 1990-2005 period. We model knowledge spillovers across cities according to three specific interaction patterns depending either on geography or on global advanced services or thought a combination of these patterns. We show that the mixed pattern matters the best for economic growth of cities in Europe.
Recursion at the crossroads of sequence modeling, random trees, stochastic algorithms and martingales
2013
This monograph synthesizes several studies spanning from dynamical systems in the statistical analysis of sequences, to analysis of algorithms in random trees and discrete stochastic processes. These works find applications in various fields ranging from biological sequences to linear regression models, branching processes, through functional statistics and estimates of risk indicators for insurances. All the established results use, in one way or another, the recursive property of the structure under study, by highlighting invariants such as martingales, which are at the heart of this monograph, as tools as well as objects of study.
Development of sport and school burnout among student-athletes across the first year of upper secondary school : different methodological perspectives
2018
The present research investigated the co-development of sport and school burnout symptoms (sport- or school-related exhaustion, cynicism, and feelings of inadequacy) among student-athletes during the first year of upper secondary school. Furthermore, the environment- and individual-related predictors of sport and school burnout were examined. The participants were student- athletes (Ntime 1=391; Ntime 2=373) from six Finnish upper secondary sport schools and their 260 mothers and 188 fathers. Athletes and their parents filled out questionnaires at the beginning of upper secondary school. Athletes answered the questionnaires again at the end of the school year, and a subsample of high-level …
MOTIVACIÓN Y ESTILO ATRIBUCIONAL SOBRE EL RENDIMIENTO ACADÉMICO EN EDUCACIÓN INFANTIL
2016
El presente trabajo tiene como objetivo examinar el poder predictivo de variables del sistema motivacional sobre las habilidades iniciales de lectura y matemáticas en una muestra de niños de Educación Infantil. Participaron 209 preescolares (5-6 años) y sus maestros. Se evaluaron las habilidades matemáticas de conteo, conocimiento de los números, cálculo y resolución de problemas. Para determinar el rendimiento en lectura se administraron tareas de identificación de letras y de lectura de palabras. Respecto al sistema motivacional, se analizaron las variables de competencia-motivación, atención-persistencia y actitud hacia el aprendizaje, así como las dimensiones de internalidad, globalida…
Motywacja jako zmienna w badaniach pedagogicznych z odniesieniami do aktywności sportowej
2018
Celem artykułu jest zaprezentowanie roli motywacji w wychowaniu i w sporcie, w kontekście traktowania motywacji jako zmiennej zależnej bądź zmiennej niezależnej w badaniach edukacyjnych. Motywacja może mieć wpływ na osiąganie pożądanych wyników w nauce i w sporcie. Możliwa jest jednak także sytuacja odwrotna: lepsze wyniki i osiągnięcia mogą zwiększać poziom motywacji do podejmowania dalszych wysiłków. Artykuł składa się z trzech części. W pierwszej przywołane są najważniejsze koncepcje i stanowiska dotyczące motywacji, w drugiej opisane są różne sposoby traktowania motywacji jako zmiennej w badaniach. W trzeciej części – przy uwzględnieniu tych różnic – ukazane są możliwe konsekwencje i po…