PubMed Health⌕ Search
Home/Archive/PubMed

PubMed · 7766781

Latent variable models for clustered ordinal data.

Y Qu·M R Piedmonte·S V Medendorp
View original source ↗Export metadata ↓

Abstract

Existing methods for the analysis of clustered, ordinal data are inappropriate for certain applications. We propose latent variable models for clustered ordinal data which are derived as natural extensions of latent variable models for clustered binary data (Qu, Williams, Beck, and Medendorp, 1992. Biometrics 48, 1095-1102). These models can be applied to repeated measures data, familial data, longitudinal data, and data with both cluster specific and occasion specific covariates with a wide range of correlation structures.

Explore related subjects

Analysis of VarianceArmBiometryCluster AnalysisDouble-Blind MethodFaceHumansModels, StatisticalOdds RatioOintmentsProbabilityRandomized Controlled Trials as TopicSkin AgingSunlightTime FactorsTretinoinUltraviolet RaysJournal Article

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Y Qu, M R Piedmonte, S V Medendorp. 1995. Latent variable models for clustered ordinal data.. https://pubmed.ncbi.nlm.nih.gov/7766781/

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

PubMed2014

Molecular heterochrony and the evolution of sociality in bumblebees (Bombus terrestris).

Sibling care is a hallmark of social insects, but its evolution remains challenging to explain at the molecular level. The hypothesis that sibling care evolved from ancestral maternal care in primitively eusocial insects has been elaborated to involve heterochronic changes in gene expression. This elaboration leads to the prediction that workers in these species will show patterns of gene expression more similar to foundress queens, who express maternal care behaviour, than to established queens engaged solely in reproductive behaviour. We tested this idea in bumblebees (Bombus terrestris) using a microarray platform with approximately 4500 genes. Unlike the wasp Polistes metricus, in which support for the above prediction has been obtained, we found that patterns of brain gene expression in foundress and queen bumblebees were more similar to each other than to workers. Comparisons of differentially expressed genes derived from this study and gene lists from microarray studies in Polistes and the honeybee Apis mellifera yielded a shared set of genes involved in the regulation of related social behaviours across independent eusocial lineages. Together, these results suggest that multiple independent evolutions of eusociality in the insects might have involved different evolutionary routes, but nevertheless involved some similarities at the molecular level.

Analysis of Variance↗
PubMed2005

Population structure and properties of Candida albicans, as determined by multilocus sequence typing.

We submitted a panel of 416 isolates of Candida albicans from separate sources to multilocus sequence typing (MLST). The data generated determined a population structure in which four major clades of closely related isolates were delineated, together with eight minor clades comprising five or more isolates. By Fisher's exact test, a statistically significant association was found between particular clades and the anatomical source, geographical source, ABC genotype, decade of isolation, and homozygosity versus heterozygosity at the mating type-like locus (MTL) of the isolates in the clade. However, these associations may have been influenced by confounding variables, since in a univariate analysis of variance, only the clade associations with ABC type and anatomical source emerged as statistically significant, providing the first indication of possible differences between C. albicans strain type clades and their propensity to infect or colonize different anatomical locations. There were no significant differences between clades with respect to distributions of isolates resistant to fluconazole, itraconazole, or flucytosine. However, the majority of flucytosine-resistant isolates belonged to clade 1, and these isolates, but not flucytosine-resistant isolates in other clades, bore a unique mutation in the FUR1 gene that probably accounts for their resistance. A significantly higher proportion of isolates resistant to fluconazole, itraconazole, and flucytosine were homozygous at the MTL, suggesting that antifungal pressure may trigger a common mechanism that leads both to resistance and to MTL homozygosity. The utility of MLST for determining clade assignments of clinical isolates will form the basis for strain selection for future research into C. albicans virulence.

Analysis of Variance↗