Search results for "Variables"
showing 10 items of 578 documents
Evaluación del desarrollo madurativo en niños y niñas de adopción internacional y la influencia de la familia en su evolución
2015
La tesis pretende analizar los cambios y mejoras en el desarrollo madurativo que se han ido produciendo en menores de adopción internacional a través de su paso por el programa de Apoyo a Familias Solicitantes de Adopción y Adoptivas. Se realizaron varias medidas desde la llegada del menor al nuevo hogar siguiendo un diseño longitudinal, en el cual también participaron las familias desde el inicio del proceso adoptivo (antes de la llegada del menor, y posteriormente a su llegada). Se ha evaluado una muestra de menores procedentes de diferentes países como China, Países del Este, Etiopía etc. La evaluación del desarrollo madurativo se ha realizado por un lado, a través de la Escala de Desarr…
Canonical correlation in multivariate time series analysis
1997
We analyze a class o f state space identification algorithms for time series, based on canonical correlation analysis in the ligth of recent results on stochastic systems theory calle d « subspace methods » .These can be describe as covariance estimation followed b y stochastic realization .The methods offer the major advantage o f converting the nonlinear parameter estimation phase in traditional V A R M A models identification in to the solution o f Riccati equation but introduce at the same time some no n trivial mathematical problem s related to positivity. The states o f the forward -backward innovations representation have an interpretation : Instrumental Variables estimators .
A New Multinomial Accuracy Measure for Polling Bias
2014
In this article, we propose a polling accuracy measure for multi-party elections based on a generalization of Martin, Traugott, and Kennedy's two-party predictive accuracy index. Treating polls as random samples of a voting population, we first estimate an intercept only multinomial logit model to provide proportionate odds measures of each party's share of the vote, and thereby both unweighted and weighted averages of these values as a summary index for poll accuracy. We then propose measures for significance testing, and run a series of simulations to assess possible bias from the resulting folded normal distribution across different sample sizes, finding that bias is small even for polls…
Comparing the Climatic and Landscape Risk Factors for Lyme Disease Cases in the Upper Midwest and Northeast United States
2020
Lyme disease, recognized as one of the most important vector-borne diseases worldwide, has been increasing in incidence and spatial extend in United States. In the Northeast and Upper Midwest, Lyme disease is transmitted by Ixodes scapularis. Currently, many studies have been conducted to identify factors influencing Lyme disease risk in the Northeast, however, relatively few studies focused on the Upper Midwest. In this study, we explored and compared the climatic and landscape factors that shape the spatial patterns of human Lyme cases in these two regions, using the generalized linear mixed models. Our results showed that climatic variables generally had opposite correlations with Lyme d…
Optimisation d’un modèle atmosphérique transnational de prédiction de la concentration journalière d’ozone : intégration de paramètres météorologique…
2021
International audience; L'ozone (O3) est un polluant atmosphérique secondaire formé lors de réactions photochimiques, en présence de précurseurs (NOx, COV, CO). L'exposition à l'O3 est délicate à modéliser car ce polluant présente une forte variabilité spatiotemporelle. Le but des présents travaux est d'optimiser l'évaluation des concentrations journalières d'O3 modélisées à échelle kilométrique, à l'aide de modèles MARS et de données météorologiques. La plateforme de modélisation PREVEST a généré une prédiction de concentrations maximales journalières d'O3 pour un maillage de 3km de côté. La station de mesure de la qualité de l'air du réseau ATMO-Bourgogne-Franche-Comté, Besançon-Prévoyanc…
Creación de un instrumento de decisión objetivo para la indicación de tratamiento quirúrgico vs conservador en la fractura de cadera
2022
La mortalidad tras la fractura de cadera es elevada y conocer en el ingreso el riesgo de mortalidad podría ser de utilidad para ajustar la necesidad de cuidados pre y perioperatorios, ayudar a la toma de decisiones y permitir el ajuste de riesgo en auditorías. En el Hospital de la Ribera (Alzira) hemos creado un modelo que tras el ingreso por la fractura de cadera mida el riesgo de mortalidad a los 30 (Alzira Hip Fracture Score: AHFS-30) y 180 días (AHFS-180). Métodos: Se incluyeron 701 pacientes mayores de 69 años, ingresados de forma consecutiva por cualquier tipo de fractura de cadera. Se recogieron las variables asociadas a mortalidad en estudios previos. Se realizó una regresión logíst…
Two‐dimensional metric spheres from gluing hemispheres
2022
We study metric spheres (Z,dZ) obtained by gluing two hemispheres of S2 along an orientation-preserving homeomorphism g:S1→S1, where dZ is the canonical distance that is locally isometric to S2 off the seam. We show that if (Z,dZ) is quasiconformally equivalent to S2, in the geometric sense, then g is a welding homeomorphism with conformally removable welding curves. We also show that g is bi-Lipschitz if and only if (Z,dZ) has a 1-quasiconformal parametrization whose Jacobian is comparable to the Jacobian of a quasiconformal mapping h:S2→S2. Furthermore, we show that if g−1 is absolutely continuous and g admits a homeomorphic extension with exponentially integrable distortion, then (Z,dZ) …
Sobolev homeomorphic extensions onto John domains
2020
Given the planar unit disk as the source and a Jordan domain as the target, we study the problem of extending a given boundary homeomorphism as a Sobolev homeomorphism. For general targets, this Sobolev variant of the classical Jordan-Schoenflies theorem may admit no solution - it is possible to have a boundary homeomorphism which admits a continuous $W^{1,2}$-extension but not even a homeomorphic $W^{1,1}$-extension. We prove that if the target is assumed to be a John disk, then any boundary homeomorphism from the unit circle admits a Sobolev homeomorphic extension for all exponents $p<2$. John disks, being one sided quasidisks, are of fundamental importance in Geometric Function Theory.
Mathematical Models and their Solutions for Domains of Compex Form
2014
Promocijas darbā tiek apskatīti dažādi oriģināli modeļi un to risinājumi sarežģītas formas apgabaliem. Intensīvās tērauda rūdīšanas procesi sistēmām ar ribām tiek aprakstīti ar 3D hiperbolisko, kā arī ar klasisko siltuma vadīšanas vienādojumu. Precīzā atrisinājuma iegūšanai izmantota Grīna funkciju metode un tās vispārinājums. Modernajos datoros sastopamajām sistēmām ar dubulsieniņu un dubultribu dota stacionārā un nestacionārā siltumvadīšanas problēma 2D gadījumā. Tās risinājums tiek iegūts ar konservatīvās viduvēšanas metodi, galīgo diferenču metodi un tās modifikāciju robežnosacījumiem. Piedāvāts jauns matemātiskais modelis vītola flautai, problēmas formulējumā izmantojot 1D lineāru viļņ…