Evaluation of the Orthogonal Projection on Latent Structure Model Limitations Caused by Chemical Shift Variability and Improved Visualization of Biomarker Changes in1H NMR Spectroscopic Metabonomic Studies

2005 ◽  
Vol 77 (2) ◽  
pp. 517-526 ◽  
Author(s):  
Olivier Cloarec ◽  
Marc E. Dumas ◽  
Johan Trygg ◽  
Andrew Craig ◽  
Richard H. Barton ◽  
...  

2019 ◽  
Vol 35 (23) ◽  
pp. 4886-4897 ◽  
Author(s):  
David M Swanson ◽  
Tonje Lien ◽  
Helga Bergholtz ◽  
Therese Sørlie ◽  
Arnoldo Frigessi

Abstract Motivation Unsupervised clustering is important in disease subtyping, among having other genomic applications. As genomic data has become more multifaceted, how to cluster across data sources for more precise subtyping is an ever more important area of research. Many of the methods proposed so far, including iCluster and Cluster of Cluster Assignments (COCAs), make an unreasonable assumption of a common clustering across all data sources, and those that do not are fewer and tend to be computationally intensive. Results We propose a Bayesian parametric model for integrative, unsupervised clustering across data sources. In our two-way latent structure model, samples are clustered in relation to each specific data source, distinguishing it from methods like COCAs and iCluster, but cluster labels have across-dataset meaning, allowing cluster information to be shared between data sources. A common scaling across data sources is not required, and inference is obtained by a Gibbs Sampler, which we improve with a warm start strategy and modified density functions to robustify and speed convergence. Posterior interpretation allows for inference on common clusterings occurring among subsets of data sources. An interesting statistical formulation of the model results in sampling from closed-form posteriors despite incorporation of a complex latent structure. We fit the model with Gaussian and more general densities, which influences the degree of across-dataset cluster label sharing. Uniquely among integrative clustering models, our formulation makes no nestedness assumptions of samples across data sources so that a sample missing data from one genomic source can be clustered according to its existing data sources. We apply our model to a Norwegian breast cancer cohort of ductal carcinoma in situ and invasive tumors, comprised of somatic copy-number alteration, methylation and expression datasets. We find enrichment in the Her2 subtype and ductal carcinoma among those observations exhibiting greater cluster correspondence across expression and CNA data. In general, there are few pan-genomic clusterings, suggesting that models assuming a common clustering across genomic data sources might yield misleading results. Availability and implementation The model is implemented in an R package called twl (‘two-way latent’), available on CRAN. Data for analysis are available within the R package. Supplementary information Supplementary data are available at Bioinformatics online.



2014 ◽  
Vol 35 (8) ◽  
pp. 1739-1770 ◽  
Author(s):  
FENGYAN TANG ◽  
JEFFREY A. BURR

ABSTRACTA dynamic latent structure model of the work–retirement transition process was identified, focusing on transitions of work and retirement status for men and women aged 51–74 years. Using the Health and Retirement Study data (1998–2004), latent transition analysis was used to identify a best fitting model capturing work–retirement statuses in four samples defined by age and sex. The prevalence of each status was described and the dynamic transition probabilities within the latent structure were examined. Using multinomial logistic regression, socio-demographic, health, family and occupational factors were assessed to determine how each was related to the likelihood of occupying a specific latent status at baseline. Results showed that study respondents were classified into distinct groups: full retiree, partial retiree or part-time worker, full-time worker, work-disabled or home-maker. The prevalence of full retiree status increased, while the prevalence for full-time worker status decreased over time for both men and women. Membership rates in the work-disabled and partial retiree status were generally consistent, with decreased probabilities of the work-disabled status in the older age groups and increased probabilities of partial retirees among younger men. Our findings indicated that many older Americans experience multiple transitions on the pathway to retirement. Future research on late-life labour-force transitions should evaluate the impact of the recent Great Recession and examine the role of larger socio-economic contexts.





Author(s):  
Curtis K. Deutsch ◽  
Steven Matthysse ◽  
James M. Swanson ◽  
Leslie G. Farkas


1970 ◽  
Vol 73 (1) ◽  
pp. 23-40 ◽  
Author(s):  
Fred Damarin




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