Search results for "Linear Model"
showing 10 items of 598 documents
Fat intake in children with autism spectrum disorder in the Mediterranean region (Valencia, Spain)
2015
Children with autism spectrum disorder (ASD) have been found to have alterations in dietary fat intake and fat quality. The fat intakes of the foods consumed by children with and without ASD were compared, and the deficiency and excess of these nutrients were examined.In a matched case-control study, 3-day food diaries were completed by 105 children with ASD and 495 typically developing (TD) 6- to 9-year-old children in Valencia (Spain). We used the probabilistic approach and estimated average requirement cut-point to evaluate the risk of inadequate nutrients intakes. These were compared between groups and with Spanish recommendations using linear and logistic regression, respectively.Group…
On Rao Score and Pearson X2 Statistics in Generalized Linear Models
2005
The identity of the Rao score and PearsonX 2 statistics is well known in the areas where the latter was first introduced: goodness-of-fit in contingency tables and binary responses. We show in this paper that the same identity holds when the two statistics are used for testing goodness-of-fit of Generalized Linear Models. We also highlight the connections that exist between the two statistics when they are used for the comparison of nested models. Finally, we discuss some merits of these unifying results.
Efficient estimation of generalized linear latent variable models.
2019
Generalized linear latent variable models (GLLVM) are popular tools for modeling multivariate, correlated responses. Such data are often encountered, for instance, in ecological studies, where presence-absences, counts, or biomass of interacting species are collected from a set of sites. Until very recently, the main challenge in fitting GLLVMs has been the lack of computationally efficient estimation methods. For likelihood based estimation, several closed form approximations for the marginal likelihood of GLLVMs have been proposed, but their efficient implementations have been lacking in the literature. To fill this gap, we show in this paper how to obtain computationally convenient estim…
Nonlinear dynamics of interest rate and inflation
2004
According to several empirical studies, US inflation and nominal interest rates, as well as the real interest rate, can be described as unit root processes. These results imply that nominal interest rates and expected inflation do not move one-for-one in the long run, which is not consistent with the theoretical models. In this paper we introduce a nonlinear bivariate mixture autoregressive model that seems to fit quarterly US data (1952 Q1 – 2000 Q2) reasonably well. It is found that the three-month treasury bill rate and inflation share a common nonlinear component that explains a large part of their persistence. The real interest rate is devoid of this component, indicating one-for-one m…
Distance decay 2.0 – a global synthesis of taxonomic and functional turnover in ecological communities
2021
AbstractUnderstanding the variation in community composition and species abundances, i.e., β-diversity, is at the heart of community ecology. A common approach to examine β-diversity is to evaluate directional turnover in community composition by measuring the decay in the similarity among pairs of communities along spatial or environmental distances. We provide the first global synthesis of taxonomic and functional distance decay along spatial and environmental distance by analysing 149 datasets comprising different types of organisms and environments. We modelled an exponential distance decay for each dataset using generalized linear models and extracted r2 and slope to analyse the streng…
Do GOLD stages of COPD severity really correspond to differences in health status?
2003
The purpose of this study was to assess whether different stages of chronic obstructive pulmonary disease (COPD) severity defined according to the Global Initiative for Chronic Obstructive Lung Disease (GOLD) criteria correlate with meaningful differences in health status. A total of 381 COPD patients, aged 73+/-6 yrs, were classified in the five GOLD stages. Disease-specific (St George Respiratory Questionnaire (SGRQ)) and generic indexes of health status were measured in all patients. Multivariate analysis of covariance or Kruskal Wallis tests were used to compare health status indexes across the spectrum of GOLD stages of COPD severity. GOLD stages of COPD severity significantly differed…
Physical activity and sedentary time in relation to academic achievement in children
2017
Objectives To investigate the independent and combined associations of objectively measured moderate-to-vigorous physical activity (MVPA) and sedentary time (ST) with reading and arithmetic skills. Design Cross-sectional/prospective. Methods Participants were 89 boys and 69 girls aged 6–8 years. MVPA and ST were measured using a combined heart rate and movement sensor and body fat percentage by dual-energy X-ray absorptiometry in Grade 1. Reading fluency, reading comprehension, and arithmetic skills were assessed using standardized tests in Grades 1–3. The data were analyzed using linear regression analyses and analyses of covariance with repeated measures. Results In boys, MVPA was directl…
Growth patterns at distal radius and tibial shaft in pubertal girls: a 2-year longitudinal study.
2005
Bone changes, in terms of both size and BMD, were assessed longitudinally in pubertal girls. Before puberty, BMD at the distal radius declined, whereas bone size increased, suggesting that normal growing girls experience a transient period of increased bone fragility. This could explain the elevated low-trauma forearm fracture rates reported in earlier studies. Introduction: Longitudinal data on bone growth during puberty are sparse. Such information is needed to understand the sequence of biological changes, the physical and mechanical consequences for the growing skeleton, and the implications for later life. Materials and Methods: The geometric properties and volumetric BMD (vBMD) of the…
The Use of Lower or Higher Than Recommended Doses of Folic Acid Supplements during Pregnancy Is Associated with Child Attentional Dysfunction at 4–5 …
2021
We assessed the association between the use of lower- and higher-than-recommended doses of folic acid supplements (FAs) during pregnancy and attentional function in boys and girls at age of 4–5. We analyzed data from 1329 mother-child pairs from the mother-child cohort INfancia y Medio Ambiente Project (INMA) study. Information on FAs use during pregnancy was collected in personal interviews at weeks 12 and 30, and categorized in <
Asymptomatic carotid lesions add to cardiovascular risk prediction.
2010
AIM To show that subclinical atherosclerosis (subclinical-ATS) of carotid arteries [intima-media thickness (IMT) or asymptomatic carotid plaque (ACP)], may provide additional information for risk stratification, in asymptomatic patients, aged greater than 45 years, with a cluster of risk factors (RFs). METHODS AND RESULTS We studied 558 asymptomatic patients (235 males). RFs for atherosclerosis were assessed and the 10-year-risk was calculated according to the Italian risk score. Doppler ultrasound of carotid arteries identified the presence of IMT greater than 0.9 mm in 183 patients and ACP in 147 patients. One hundred and fifty-three patients developed cerebrovascular or cardiovascular (C…