Biometry Commons^™

Unified Methods For Feature Selection In Large-Scale Genomic Studies With Censored Survival Outcomes, Lauren Spirko-Burns, Karthik Devarajan

COBRA Preprint Series

One of the major goals in large-scale genomic studies is to identify genes with a prognostic impact on time-to-event outcomes which provide insight into the disease's process. With rapid developments in high-throughput genomic technologies in the past two decades, the scientific community is able to monitor the expression levels of tens of thousands of genes and proteins resulting in enormous data sets where the number of genomic features is far greater than the number of subjects. Methods based on univariate Cox regression are often used to select genomic features related to survival outcome; however, the Cox model assumes proportional hazards …

Application Of Non-Rated Line Officer Attrition Levels And Career Field Stability, Christine L. Zens

Theses and Dissertations

The Air Force monitors the strength of its active duty officer force and attempts to achieve the difficult challenge of employing a diversity of talent among career specialties and experience levels. This study completes two objectives, predicting future manning levels for 23 career fields, and providing a statistical framework to assess the stability of these fields. The first part of the study applies regression and survival analysis to subpopulations within the active duty Air Force officer corps, and then aggregates them by year to forecast future personnel levels. Four career fields are considered, including Acquisitions (ACQ), Logistics (LOG), Support (SPT), …

Models For Hsv Shedding Must Account For Two Levels Of Overdispersion, Amalia Magaret

UW Biostatistics Working Paper Series

We have frequently implemented crossover studies to evaluate new therapeutic interventions for genital herpes simplex virus infection. The outcome measured to assess the efficacy of interventions on herpes disease severity is the viral shedding rate, defined as the frequency of detection of HSV on the genital skin and mucosa. We performed a simulation study to ascertain whether our standard model, which we have used previously, was appropriately considering all the necessary features of the shedding data to provide correct inference. We simulated shedding data under our standard, validated assumptions and assessed the ability of 5 different models to reproduce the …

Immediate Implant Placement In Extraction Sites With Periapical Lesions: A Retrospective Study, Yuan-Lung Hung

Loma Linda University Electronic Theses, Dissertations & Projects

Immediate implant placement into fresh extraction sites has become a relatively routine clinical procedure with a favorable prognosis. However, immediate placement into extraction sockets with lesions has not been extensively documented in humans. Therefore, the purpose of this study was to retrospectively determine the survival rate of implants placed into extraction sockets with visible periapical lesions.

Patient charts of 544 immediately placed implants from Loma Linda University School of Dentistry, Center for Prosthodontics and Implant Dentistry were examined. Eighty-six of the 544 implants had been placed immediately into extraction sockets with periapical lesions and they were included in this study. …