Comparación de métodos robustos para el análisis canónico asimétrico

El análisis de canónico asimétrico o redundancia busca para dos grupos de variables las combinaciones lineales en un grupo que maximicen la varianza explicada del otro por dicha combinación lineal. En este trabajo se propone un método robusto para el análisis de redundancia basado en estimadores para regresión lineal multivariada. Se mostrará el buen desempeño de los métodos propuestos comparado con el método clásico y otros métodos basados en matrices de correlación robustas, mediante un estudio de simulación utilizando muestras con y sin contaminación.Facultad de Ciencias Exacta

Comparación de métodos robustos para el análisis canónico asimétrico

El análisis de canónico asimétrico o redundancia busca para dos grupos de variables las combinaciones lineales en un grupo que maximicen la varianza explicada del otro por dicha combinación lineal. En este trabajo se propone un método robusto para el análisis de redundancia basado en estimadores para regresión lineal multivariada. Se mostrará el buen desempeño de los métodos propuestos comparado con el método clásico y otros métodos basados en matrices de correlación robustas, mediante un estudio de simulación utilizando muestras con y sin contaminación.Facultad de Ciencias Exacta

Comparación de métodos robustos para el análisis canónico asimétrico

El análisis de canónico asimétrico o redundancia busca para dos grupos de variables las combinaciones lineales en un grupo que maximicen la varianza explicada del otro por dicha combinación lineal. En este trabajo se propone un método robusto para el análisis de redundancia basado en estimadores para regresión lineal multivariada. Se mostrará el buen desempeño de los métodos propuestos comparado con el método clásico y otros métodos basados en matrices de correlación robustas, mediante un estudio de simulación utilizando muestras con y sin contaminación.Facultad de Ciencias Exacta

Development and validation of a diet quality index based on recommendations of the Dietary Guidelines for the Argentine Population

INTRODUCCIÓN: Los índices de calidad de dieta son herramientas útiles para evaluar patrones alimentarios y adherencia a guías alimentarias. El objetivo fue desarrollar y validar un índice basado en las Guías Alimentarias para la Población Argentina (GAPA). MÉTODOS: Se desarrolló un índice basado en las guías locales, se analizó la validez de contenido por expertos y la validez de constructo y confiabilidad mediante un estudio de corte transversal. Se incluyó a voluntarios adultos sanos y se relevó información general y de consumo de alimentos. Se analizó la capacidad de otorgar puntajes variados y hallar diferencias entre grupos. Se evaluó la correlación entre el puntaje total y cada componente, y con la ingesta energética y de nutrientes. Se exploraron dimensiones subyacentes con análisis de componentes principales. Se analizó la consistencia interna mediante alfa de Cronbach. RESULTADOS: Se desarrolló un Índice de Calidad de Dieta Argentino (ICDAr) que refleja ocho mensajes principales de las guías y se halló buena aceptación por expertos (V de Aiken ≥0,8; p<0,05). El ICDAr demostró amplitud de rango (37,36-86,39) y diferencia entre fumadores y no fumadores (p=0,002). Se halló correlación positiva entre el puntaje total y cada componente y una mejor ingesta de nutrientes, pero no con ingesta energética. Se hallaron múltiples dimensiones subyacentes. El alfa de Cronbach fue 0,49. DISCUSIÓN: El ICDAr es válido para evaluar la calidad de dieta según la adherencia a las GAPA.INTRODUCTION: Diet quality indices are useful tools to assess dietary patterns and adherence to dietary guidelines. The objective was to develop and validate an index based on the Dietary Guidelines for the Argentine Population (GAPA). METHODS: An index based on local dietary guidelines was developed, content validity was analyzed by experts, and construct validity and reliability were analyzed through a cross-sectional study. Healthy adult volunteers were included, and general and food consumption data were collected. The ability to give varied scores and find differences between groups was analyzed. The correlation between the total score and each component, and with energy and nutrient intake was evaluated. Underlying dimensions were explored using principal component analysis. Internal consistency was analyzed using Cronbach’s alpha. RESULTS: An Argentine Diet Quality Index (ICDAr) was developed which reflects eight main messages of the guidelines and was found to be well accepted by experts (Aiken’s V ≥0.8; p&lt;0.05). The ICDAr showed a wide range (37.36-86.39) and a difference between smokers and non-smokers (p=0.002). A positive correlation was found between the total score and each component and a better nutrient intake, but not with energy intake. Multiple underlying dimensions were found. Cronbach’s alpha was 0.49. DISCUSSION: The ICDAr is valid to assess diet quality according to adherence to the GAPA.Facultad de Ciencias ExactasFacultad de Ciencias Médica

Continuity and differentiability of regression M functionals

This paper deals with the Fisher-consistency, weak continuity and differentiability of estimating functionals corresponding to a class of both linear and nonlinear regression high breakdown M estimates, which includes S and MM estimates. A restricted type of differentiability, called weak differentiability, is defined, which suffices to prove the asymptotic normality of estimates based on the functionals. This approach allows to prove the consistency, asymptotic normality and qualitative robustness of M estimates under more general conditions than those required in standard approaches. In particular, we prove that regression MMestimates are asymptotically normal when the observations are φ-mixing.Facultad de Ciencias Exacta

Consequences of Lockdown During COVID-19 Pandemic in Lifestyle and Emotional State of Children in Argentina

The implications of the coronavirus disease (COVID-19) lockdown measurements and social isolation in children and their parents are still unknown. The aims of this study were to examine the impact of COVID-19 lockdown on emotional state, feelings and lifestyle of children and their parents, to explore the association between parental characteristics and child well-being and to examine whether the impact of lockdown depends on socio-economic status. Parents completed an online survey including data about socio-demographic information, parent and child feelings and lifestyle during lockdown. Logistic regression and correlation analysis were used to establish associations between variables. In total, 814 parents with children between 4 and 11 were included in the study. According to parents, 69.5% of the children showed changes in their emotional state, 55.3% altered their routine and 62.6% showed sleep disorders. Families with lower socio-economic status were more worried about health, shortage of food and household income (p < 0.01). Parent and children concern about food/essential items were highly associated [OR (CI 95%) 13.0 (6.81, 26.5), p < 0.01]. Adverse children’s emotional state was associated with parental feeling of loneliness (r = 0.35) and inversely associated with keeping a routine (r = −0.11). Sleep changes were inversely associated with keeping a routine and having a balcony/garden (r = −0.53 and −0.16). We conclude that lockdown affected emotional state and lifestyle of children and parents, which were strongly related. Routine and positive parental attitude supported children’s well-being. Economic issues were an important concern in families with lower socio-economic status. Our findings can help to promote child health during lockdown.Fil: Fasano, Maria Victoria. Provincia de Buenos Aires. Ministerio de Salud. Hospital de Niños "Sor María Ludovica" de La Plata. Instituto de Desarrollo e Investigaciones Pediátricas; Argentina. Universidad Nacional de la Plata. Facultad de Cs.exactas. Centro de Matematica de la Plata.; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Padula, Marcela. Provincia de Buenos Aires. Ministerio de Salud. Hospital de Niños "Sor María Ludovica" de La Plata. Instituto de Desarrollo e Investigaciones Pediátricas; ArgentinaFil: Azrak, María Ángeles. Provincia de Buenos Aires. Ministerio de Salud. Hospital de Niños "Sor María Ludovica" de La Plata. Instituto de Desarrollo e Investigaciones Pediátricas; ArgentinaFil: Avico, Ana Julia. Provincia de Buenos Aires. Ministerio de Salud. Hospital de Niños "Sor María Ludovica" de La Plata. Instituto de Desarrollo e Investigaciones Pediátricas; ArgentinaFil: Sala, Marisa. Provincia de Buenos Aires. Ministerio de Salud. Hospital de Niños "Sor María Ludovica" de La Plata. Instituto de Desarrollo e Investigaciones Pediátricas; ArgentinaFil: Andreoli, Maria Florencia. Provincia de Buenos Aires. Ministerio de Salud. Hospital de Niños "Sor María Ludovica" de La Plata. Instituto de Desarrollo e Investigaciones Pediátricas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentin

Continuity and differentiability of regression M functionals

This paper deals with the Fisher-consistency, weak continuity and differentiability of estimating functionals corresponding to a class of both linear and nonlinear regression high breakdown M estimates, which includes S and MM estimates. A restricted type of differentiability, called weak differentiability, is defined, which suffices to prove the asymptotic normality of estimates based on the functionals. This approach allows to prove the consistency, asymptotic normality and qualitative robustness of M estimates under more general conditions than those required in standard approaches. In particular, we prove that regression MMestimates are asymptotically normal when the observations are φ-mixing.Facultad de Ciencias Exacta

Consequences of Lockdown During COVID-19 Pandemic in Lifestyle and Emotional State of Children in Argentina

The implications of the coronavirus disease (COVID-19) lockdown measurements and social isolation in children and their parents are still unknown. The aims of this study were to examine the impact of COVID-19 lockdown on emotional state, feelings and lifestyle of children and their parents, to explore the association between parental characteristics and child well-being and to examine whether the impact of lockdown depends on socio-economic status. Parents completed an online survey including data about socio-demographic information, parent and child feelings and lifestyle during lockdown. Logistic regression and correlation analysis were used to establish associations between variables. In total, 814 parents with children between 4 and 11 were included in the study. According to parents, 69.5% of the children showed changes in their emotional state, 55.3% altered their routine and 62.6% showed sleep disorders. Families with lower socio-economic status were more worried about health, shortage of food and household income (p < 0.01). Parent and children concern about food/essential items were highly associated [OR (CI 95%) 13.0 (6.81, 26.5), p < 0.01]. Adverse children's emotional state was associated with parental feeling of loneliness (r = 0.35) and inversely associated with keeping a routine (r = -0.11). Sleep changes were inversely associated with keeping a routine and having a balcony/garden (r = -0.53 and -0.16). We conclude that lockdown affected emotional state and lifestyle of children and parents, which were strongly related. Routine and positive parental attitude supported children's well-being. Economic issues were an important concern in families with lower socio-economic status. Our findings can help to promote child health during lockdown.Facultad de Ciencias Exacta

Impact of atomic defects in the electronic states of FeSe1-x Sx superconducting crystals

The electronic properties of Fe-based superconductors are drastically affected by deformations on their crystal structure introduced by doping and pressure. Here we study single crystals of FeSe 1 − x Sx and reveal that local crystal deformations such as atomic-scale defects impact the spectral shape of the electronic core level states of the material. By means of scanning tunneling microscopy we image S-doping induced defects as well as diluted dumbbell defects associated with Fe vacancies. We have access to the electronic structure of the samples by means of x-ray photoemission spectroscopy (XPS) and show that the spectral shape of the Se core levels can only be adequately described by considering a principal plus a minor component of the electronic states. We find this result for both pure and S-doped samples, irrespective that in the latter case the material presents extra crystal defects associated to doping with S atoms. We argue that the second component in our XPS spectra is associated with the ubiquitous dumbbell defects in FeSe that are known to entail a significant modification of the electronic clouds of surrounding atoms