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Statistics and Probability

2012

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Articles 1 - 30 of 85

Full-Text Articles in Medicine and Health Sciences

Piscine Myocarditis Virus (Pmcv) In Wild Atlantic Salmon Salmo Salar, Torstein Tengs Dr. Dec 2012

Piscine Myocarditis Virus (Pmcv) In Wild Atlantic Salmon Salmo Salar, Torstein Tengs Dr.

Dr. Torstein Tengs

Cardiomyopathy syndrome (CMS) is a severe cardiac disease of sea-farmed Atlantic salmon Salmo salar L., but CMS-like lesions have also been found in wild Atlantic salmon. In 2010 a double-stranded RNA virus of the Totiviridae family, provisionally named piscine myocarditis virus (PMCV), was described as the causative agent of CMS. In the present paper we report the first detection of PMCV in wild Atlantic salmon. The study is based on screening of 797 wild Atlantic salmon by real-time RT-PCR. The samples were collected from 35 different rivers along the coast of Norway, and all individuals included in the study were …


Multiple Subject Barycentric Discriminant Analysis (Musubada): How To Assign Scans To Categories Without Using Spatial Normalization, Hervé Abdi, Lynne J. Williams, Andrew C. Connolly, M. Ida Gobbini Dec 2012

Multiple Subject Barycentric Discriminant Analysis (Musubada): How To Assign Scans To Categories Without Using Spatial Normalization, Hervé Abdi, Lynne J. Williams, Andrew C. Connolly, M. Ida Gobbini

Dartmouth Scholarship

We present a new discriminant analysis (DA) method called Multiple Subject Barycentric Discriminant Analysis (MUSUBADA) suited for analyzing fMRI data because it handles datasets with multiple participants that each provides different number of variables (i.e., voxels) that are themselves grouped into regions of interest (ROIs). Like DA, MUSUBADA (1) assigns observations to predefined categories, (2) gives factorial maps displaying observations and categories, and (3) optimally assigns observations to categories. MUSUBADA handles cases with more variables than observations and can project portions of the data table (e.g., subtables, which can represent participants or ROIs) on the factorial maps. Therefore MUSUBADA can …


Evaluation Of The Survival Effect For Various Treatment Modalities Among Stage Ii And Iii Rectal Cancer Patients In California, 1994-2009, Myung Mi Cho Dec 2012

Evaluation Of The Survival Effect For Various Treatment Modalities Among Stage Ii And Iii Rectal Cancer Patients In California, 1994-2009, Myung Mi Cho

Loma Linda University Electronic Theses, Dissertations & Projects

Background: European trials evaluating the effect of preoperative (PreOP) versus postoperative chemoradiotherapy (PostOP CRT) found no survival benefit. However, the effect of a change from PostOP to PreOP CRT has not been evaluated in a population-based setting. We sought to evaluate multimodal treatment changes and overall survival for perioperative (PeriOP) CRT versus surgery alone and for PreOP versus PostOP CRT from 1994 through 2009 among patients receiving radical surgery for stage II and III rectal cancer (RC).

Patients and Methods: We conducted a nonconcurrent cohort study evaluating demographic predictors of multimodal therapy for stage II and III RC using …


A Regionalized National Universal Kriging Model Using Partial Least Squares Regression For Estimating Annual Pm2.5 Concentrations In Epidemiology, Paul D. Sampson, Mark Richards, Adam A. Szpiro, Silas Bergen, Lianne Sheppard, Timothy V. Larson, Joel Kaufman Dec 2012

A Regionalized National Universal Kriging Model Using Partial Least Squares Regression For Estimating Annual Pm2.5 Concentrations In Epidemiology, Paul D. Sampson, Mark Richards, Adam A. Szpiro, Silas Bergen, Lianne Sheppard, Timothy V. Larson, Joel Kaufman

UW Biostatistics Working Paper Series

Many cohort studies in environmental epidemiology require accurate modeling and prediction of fine scale spatial variation in ambient air quality across the U.S. This modeling requires the use of small spatial scale geographic or “land use” regression covariates and some degree of spatial smoothing. Furthermore, the details of the prediction of air quality by land use regression and the spatial variation in ambient air quality not explained by this regression should be allowed to vary across the continent due to the large scale heterogeneity in topography, climate, and sources of air pollution. This paper introduces a regionalized national universal kriging …


The Morbidity & Mortality Of Prevalent Heart Failure, Jennifer Kwon Dec 2012

The Morbidity & Mortality Of Prevalent Heart Failure, Jennifer Kwon

Loma Linda University Electronic Theses, Dissertations & Projects

The first study population included 292 unselected consecutive patients from the LLUMC heart failure clinic who were enrolled in the study from January to July 2006 and were followed up through the end of December 2010. The treatment policy at the clinic was to uptitrate dosages of beta-adrenergic blockade (β-blockers), angiotensin-converting-enzyme inhibitors (ACEi) and angiotensin II receptor blockers (ARB) to the most tolerable levels in order to reach target dosages, as recommended by the Heart Failure Society of America (HFSA). Patients were classified into systolic heart failure (ejection fraction (EF) < 40%) or diastolic heart failure (EF≥40%). All dosages of β-blockers, ACEi and ARB were extracted through chart reviews and were used as the main predictors of the patients' survival. Results from analyses showed that reaching target dosages of β-blockers and ACEi/ARB may increase survival when compared to not reaching target among the systolic HF population (HRβ_biockers= 0.64, 95% CI 0.26-1.56 and HRACEi/ARB=0.50, …


Limited Sampling Estimates Of Epigallocatechin Gallate Exposures In Cirrhotic And Noncirrhotic Patients With Hepatitis C After Single Oral Doses Of Green Tea Extract., Dina Halegoua-De Marzio, Walter K. Kraft, Constantine Daskalakis, Xie Ying, Roy L Hawke, Victor J. Navarro Dec 2012

Limited Sampling Estimates Of Epigallocatechin Gallate Exposures In Cirrhotic And Noncirrhotic Patients With Hepatitis C After Single Oral Doses Of Green Tea Extract., Dina Halegoua-De Marzio, Walter K. Kraft, Constantine Daskalakis, Xie Ying, Roy L Hawke, Victor J. Navarro

Division of Gastroenterology and Hepatology Faculty Papers

BACKGROUND: Epigallocatechin-3-gallate (EGCG) has antiangiogenic, antioxidant, and antifibrotic properties that may have therapeutic potential for the treatment of cirrhosis induced by hepatitis C virus (HCV). However, cirrhosis might affect EGCG disposition and augment its reported dose-dependent hepatotoxic potential.

OBJECTIVE: The safety, tolerability, and disposition of a single oral dose of EGCG in cirrhotic patients with HCV were examined in an exploratory fashion.

METHODS: Eleven patients with hepatitis C and detectable viremia were enrolled. Four had Child-Pugh (CP) class A cirrhosis, 4 had Child-Pugh class B cirrhosis, and 3 were noncirrhotic. After a single oral dose of green tea extract 400 …


Paradoxical Results Of Adaptive False Discovery Rate Procedures In Neuroimaging Studies, Philip T. Reiss, Armin Schwartzman, Feihan Lu, Lei Huang, Erika Proal Nov 2012

Paradoxical Results Of Adaptive False Discovery Rate Procedures In Neuroimaging Studies, Philip T. Reiss, Armin Schwartzman, Feihan Lu, Lei Huang, Erika Proal

Philip T. Reiss

Adaptive false discovery rate (FDR) procedures, which offer greater power than the original FDR procedure of Benjamini and Hochberg, are often applied to statistical maps of the brain. When a large proportion of the null hypotheses are false, as in the case of widespread effects such as cortical thinning throughout much of the brain, adaptive FDR methods can surprisingly reject more null hypotheses than not accounting for multiple testing at all—i.e., using uncorrected p-values. A straightforward mathematical argument is presented to explain why this can occur with the q-value method of Storey and colleagues, and a simulation study shows that …


Prediction Of Radiation Pneumonitis By Dose-Volume Histogram Parameters In Lung Cancer--A Systematic Review, George Rodrigues, Michael Lock, David D'Souza, Edward Yu, Jake Van Dyk Nov 2012

Prediction Of Radiation Pneumonitis By Dose-Volume Histogram Parameters In Lung Cancer--A Systematic Review, George Rodrigues, Michael Lock, David D'Souza, Edward Yu, Jake Van Dyk

Michael Lock

BACKGROUND AND PURPOSE: To perform a systematic review of the predictive ability of various dose-volume histogram (DVH) parameters (V(dose), mean lung dose (MLD), and normal tissue complication probability (NTCP)) in the incidence of radiation pneumonitis (RP) caused by external-beam radiation therapy.

METHODS AND MATERIALS: Studies assessing the relationship between CT-based DVH reduction parameters and RP rate in radically treated lung cancer were eligible for the review. Synonyms for RP, lung cancer, DVH and its associated parameters (NTCP, V(20), V(30), MLD) were combined in a search strategy involving electronic databases, secondary reference searching, and consultation with experts. Individual or group data …


Technology Assessment Of Automated Atlas Based Segmentation In Prostate Bed Contouring, Jeremiah Hwee, Alexander Louie, Stewart Gaede, Glenn Bauman, David D'Souza, Tracy Sexton, Michael Lock, Belal Ahmad, George Rodrigues Nov 2012

Technology Assessment Of Automated Atlas Based Segmentation In Prostate Bed Contouring, Jeremiah Hwee, Alexander Louie, Stewart Gaede, Glenn Bauman, David D'Souza, Tracy Sexton, Michael Lock, Belal Ahmad, George Rodrigues

Michael Lock

BACKGROUND: Prostate bed (PB) contouring is time consuming and associated with inter-observer variability. We evaluated an automated atlas-based segmentation (AABS) engine in its potential to reduce contouring time and inter-observer variability.

METHODS: An atlas builder (AB) manually contoured the prostate bed, rectum, left femoral head (LFH), right femoral head (RFH), bladder, and penile bulb of 75 post-prostatectomy cases to create an atlas according to the recent RTOG guidelines. 5 other Radiation Oncologists (RO) and the AABS contoured 5 new cases. A STAPLE contour for each of the 5 patients was generated. All contours were anonymized and sent back to the …


A Descriptive Study Of Childhood Cancer Statistics: Montgomery County, Jamie L. Hartig Oct 2012

A Descriptive Study Of Childhood Cancer Statistics: Montgomery County, Jamie L. Hartig

Master of Public Health Program Student Publications

Objective: This research describes childhood cancer and identifies variances in childhood cancer statistics in the United States, Ohio, and Montgomery County.

Methods: This is a descriptive analysis of childhood cancer statistics using the Ohio Cancer Incidence Surveillance System (OCISS) (Ohio Department of Health, 2010) and CDC Wonder database (United States Department of Health and Human Services [USDHHS], Centers for Disease Control and Prevention [CDC], & National Cancer Institute [NCI], 2008 & 2011.) Cancer incidences between white children and black children were compared for the years 1999-2009. The OCISS database was also used to compare vital status by race, cancer stage …


Conventional Isolated Aortic Valve Replacement In Octogenarians: A 10-Year Single Center Experience, James K. Wu Md, Justin D. Roberts Do, Gregory S. Troutman Bs, Michael J. Weiss Mph, Sanjay M. Mehta Md, Theodore G. Phillips Md, Michael F. Szwerc Md, Gary W. Szydlowski Md, Timothy S. Misselbeck, Raymond L. Singer Md Sep 2012

Conventional Isolated Aortic Valve Replacement In Octogenarians: A 10-Year Single Center Experience, James K. Wu Md, Justin D. Roberts Do, Gregory S. Troutman Bs, Michael J. Weiss Mph, Sanjay M. Mehta Md, Theodore G. Phillips Md, Michael F. Szwerc Md, Gary W. Szydlowski Md, Timothy S. Misselbeck, Raymond L. Singer Md

Department of Surgery

No abstract provided.


A Pooled Analysis Of Smoking And Colorectal Cancer: Timing Of Exposure And Interactions With Environmental Factors Sep 2012

A Pooled Analysis Of Smoking And Colorectal Cancer: Timing Of Exposure And Interactions With Environmental Factors

Shuo Jiao

Background:Considerable evidence suggests that cigarette smoking is associated with a higher risk of colorectal cancer. What is unclear, however, is the impact of quitting smoking on risk attenuation and whether other risk factors for colorectal cancer modify this association. Methods:We performed a pooled analysis of 8 studies, including 6,796 colorectal cancer cases and 7,770 controls to evaluate the association between cigarette smoking history and colorectal cancer risk, and to investigate potential effect modification by other risk factors. Results:Current smokers (OR=1.26, 95% CI=1.11-1.43) and former smokers (OR=1.18, 95% CI=1.09-1.27), relative to never smokers, showed higher risks of colorectal cancer. Former smokers …


Effects Of Genetic Variants Previously Associated With Fasting Glucose And Insulin In The Diabetes Prevention Program, Jose C. Florez, Kathleen A. Jablonski, Jarred B. Mcateer, Paul W. Franks, Clinton C. Mason, Kieren J. Mather, Edward Horton, Ronald Goldberg, Dana Dabelea, Steven E. Kahn, Richard F. Arakaki, Alan R. Shuldiner, William C. Knowler Sep 2012

Effects Of Genetic Variants Previously Associated With Fasting Glucose And Insulin In The Diabetes Prevention Program, Jose C. Florez, Kathleen A. Jablonski, Jarred B. Mcateer, Paul W. Franks, Clinton C. Mason, Kieren J. Mather, Edward Horton, Ronald Goldberg, Dana Dabelea, Steven E. Kahn, Richard F. Arakaki, Alan R. Shuldiner, William C. Knowler

Epidemiology Faculty Publications

Common genetic variants have been recently associated with fasting glucose and insulin levels in white populations. Whether these associations replicate in pre-diabetes is not known. We extended these findings to the Diabetes Prevention Program, a clinical trial in which participants at high risk for diabetes were randomized to placebo, lifestyle modification or metformin for diabetes prevention. We genotyped previously reported polymorphisms (or their proxies) in/near G6PC2, MTNR1B, GCK, DGKB, GCKR, ADCY5, MADD, CRY2, ADRA2A,FADS1, PROX1, SLC2A2, GLIS3, C2CD4B, IGF1, and IRS1 in 3,548 Diabetes …


Measuring Infertility In Populations: Constructing A Standard Definition For Use With Demographic And Reproductive Health Surveys, Maya N. Mascarenhas, Hoiwan Cheung, Colin D. Mathers, Gretchen A. Stevens Aug 2012

Measuring Infertility In Populations: Constructing A Standard Definition For Use With Demographic And Reproductive Health Surveys, Maya N. Mascarenhas, Hoiwan Cheung, Colin D. Mathers, Gretchen A. Stevens

Dartmouth Scholarship

Background: Infertility is a significant disability, yet there are no reliable estimates of its global prevalence. Studies on infertility prevalence define the condition inconsistently, rendering the comparison of studies or quantitative summaries of the literature difficult. This study analyzed key components of infertility to develop a definition that can be consistently applied to globally available household survey data.

Methods: We proposed a standard definition of infertility and used it to generate prevalence estimates using 53 Demographic and Health Surveys (DHS). The analysis was restricted to the subset of DHS that contained detailed fertility information collected through the reproductive health calendar. …


Genetic Modulation Of Lipid Profiles Following Lifestyle Modification Or Metformin Treatment: The Diabetes Prevention Program, Toni I. Pollin, Tamara Isakova, Kathleen A. Jablonski, Paul I.W. De Bakker, Andrew Taylor, Jarred B. Mcateer, Qing Pan, Edward Horton, Linda M. Delahanty, David Altshuler, Alan R. Shuldiner, Ronald Goldberg, Jose C. Florez, George A. Bray Aug 2012

Genetic Modulation Of Lipid Profiles Following Lifestyle Modification Or Metformin Treatment: The Diabetes Prevention Program, Toni I. Pollin, Tamara Isakova, Kathleen A. Jablonski, Paul I.W. De Bakker, Andrew Taylor, Jarred B. Mcateer, Qing Pan, Edward Horton, Linda M. Delahanty, David Altshuler, Alan R. Shuldiner, Ronald Goldberg, Jose C. Florez, George A. Bray

Epidemiology Faculty Publications

Weight-loss interventions generally improve lipid profiles and reduce cardiovascular disease risk, but effects are variable and may depend on genetic factors. We performed a genetic association analysis of data from 2,993 participants in the Diabetes Prevention Program to test the hypotheses that a genetic risk score (GRS) based on deleterious alleles at 32 lipid-associated single-nucleotide polymorphisms modifies the effects of lifestyle and/or metformin interventions on lipid levels and nuclear magnetic resonance (NMR) lipoprotein subfraction size and number. Twenty-three loci previously associated with fasting LDL-C, HDL-C, or triglycerides replicated (P = 0.04–1×10−17). Except for total HDL particles (r = −0.03, …


Prevalence Of Tick Borne Encephalitis Virus In Tick Nymphs In Relation To Climatic Factors On The Southern Coast Of Norway, Torstein Tengs Dr. Aug 2012

Prevalence Of Tick Borne Encephalitis Virus In Tick Nymphs In Relation To Climatic Factors On The Southern Coast Of Norway, Torstein Tengs Dr.

Dr. Torstein Tengs

BACKGROUND

Tick-borne encephalitis (TBE) is among the most important vector borne diseases of humans in Europe and is currently identified as a major health problem in many countries. TBE endemic zones have expanded over the past two decades, as well as the number of reported cases within endemic areas. Multiple factors are ascribed for the increased incidence of TBE, including climatic change. The number of TBE cases has also increased in Norway over the past decade, and the human cases cluster along the southern coast of Norway. In Norway the distribution and prevalence of TBE virus (TBEV) in tick populations …


Evaluating The Consistency Of Gene Sets Used In The Analysis Of Bacterial Gene Expression Data, Nathan L. Tintle, Alexandra Sitarik, Benjamin Boerema, Kylie Young, Aaron Best, Matthew Dejongh Aug 2012

Evaluating The Consistency Of Gene Sets Used In The Analysis Of Bacterial Gene Expression Data, Nathan L. Tintle, Alexandra Sitarik, Benjamin Boerema, Kylie Young, Aaron Best, Matthew Dejongh

Faculty Work Comprehensive List

Background

Statistical analyses of whole genome expression data require functional information about genes in order to yield meaningful biological conclusions. The Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) are common sources of functionally grouped gene sets. For bacteria, the SEED and MicrobesOnline provide alternative, complementary sources of gene sets. To date, no comprehensive evaluation of the data obtained from these resources has been performed.

Results

We define a series of gene set consistency metrics directly related to the most common classes of statistical analyses for gene expression data, and then perform a comprehensive analysis of 3581 …


Fall In C-Peptide During First 2 Years From Diagnosis: Evidence Of At Least Two Distinct Phases From Composite Type 1 Diabetes Trialnet Data., Carla J. Greenbaum, Craig A. Beam, David Boulware, Stephen E. Gitelman, Peter A. Gottlieb, Kevan C. Herold, John M. Lachin, Paula L. Mcgee, Jerry P. Palmer, Mark D. Pescovitz, Heidi Krause-Steinrauf, Jay S. Skyler, Jay M. Sosenko Aug 2012

Fall In C-Peptide During First 2 Years From Diagnosis: Evidence Of At Least Two Distinct Phases From Composite Type 1 Diabetes Trialnet Data., Carla J. Greenbaum, Craig A. Beam, David Boulware, Stephen E. Gitelman, Peter A. Gottlieb, Kevan C. Herold, John M. Lachin, Paula L. Mcgee, Jerry P. Palmer, Mark D. Pescovitz, Heidi Krause-Steinrauf, Jay S. Skyler, Jay M. Sosenko

Epidemiology Faculty Publications

Interpretation of clinical trials to alter the decline in β-cell function after diagnosis of type 1 diabetes depends on a robust understanding of the natural history of disease. Combining data from the Type 1 Diabetes TrialNet studies, we describe the natural history of β-cell function from shortly after diagnosis through 2 years post study randomization, assess the degree of variability between patients, and investigate factors that may be related to C-peptide preservation or loss. We found that 93% of individuals have detectable C-peptide 2 years from diagnosis. In 11% of subjects, there was no significant fall from baseline by 2 …


An Efficient Methodology For Learning Bayesian Networks, Emmanuel Owusu Asante-Asamani Aug 2012

An Efficient Methodology For Learning Bayesian Networks, Emmanuel Owusu Asante-Asamani

Theses and Dissertations

Statistics from the National Cancer Institute indicate that 1 in 8 women will develop Breast cancer in their lifetime. Researchers have developed numerous statistical models to predict breast cancer risk however physicians are hesitant to use these models because of disparities in the predictions they produce. In an effort to reduce these disparities, we use Bayesian networks to capture the joint distribution of risk factors, and simulate artificial patient populations (clinical avatars) for interrogating the existing risk prediction models. The challenge in this effort has been to produce a Bayesian network whose dependencies agree with literature and are good estimates …


Big Data And The Future, Sherri Rose Jul 2012

Big Data And The Future, Sherri Rose

Sherri Rose

No abstract provided.


A Comparison Of Individual Versus Community Influences On Youth Smoking Behaviours: A Cross-Sectional Observational Study, Anna M. Adachi-Mejia, Heather A. Carlos, Ethan M. Berke, Susanne E. Tanski, James Sargent Jul 2012

A Comparison Of Individual Versus Community Influences On Youth Smoking Behaviours: A Cross-Sectional Observational Study, Anna M. Adachi-Mejia, Heather A. Carlos, Ethan M. Berke, Susanne E. Tanski, James Sargent

Dartmouth Scholarship

Objectives: To compare individual with community risk factors for adolescent smoking. Design: A cross-sectional observational study with multivariate analysis.Setting: National telephone survey.Participants: 3646 US adolescents aged 13–18 years in 2007 recruited through a random digit-dial survey.


Function-On-Scalar Regression With The Refund Package, Philip T. Reiss Jul 2012

Function-On-Scalar Regression With The Refund Package, Philip T. Reiss

Philip T. Reiss

No abstract provided.


A Strain Of Piscine Myocarditis Virus (Pmcv) Infecting Argentina Silus (Ascanius), Torstein Tengs Dr. Jul 2012

A Strain Of Piscine Myocarditis Virus (Pmcv) Infecting Argentina Silus (Ascanius), Torstein Tengs Dr.

Dr. Torstein Tengs

No abstract.


Comparing Years Of Healthy Life, Measured In 16 Ways, For Normal Weight And Overweight Older Adults, Paula Diehr Jun 2012

Comparing Years Of Healthy Life, Measured In 16 Ways, For Normal Weight And Overweight Older Adults, Paula Diehr

Paula Diehr

Introduction. The traditional definitions of overweight and obesity are not age specific, even though the relationship of weight to mortality is different for older adults. Effects of adiposity on aspects of health beside mortality have not been well investigated. Methods. We calculated the number of years of healthy life (YHL) in the 10 years after baseline, for 5,747 older adults. YHL was defined in 16 different ways. We compared Normal and Overweight persons, classified either by bodymass index (BMI) or by waist circumference (WC). Findings. YHL for Normal and Overweight persons differed significantly in 25% of the comparisons, of which …


Selective Impact Of Hiv Disease Progression On The Innate Immune System In The Human Female Reproductive Tract., Timothy Lahey, Mimi Ghosh, John V. Fahey, Zheng Sheng, Lucy R. Mukura, Yan Song, Susan Cu-Uvin, Kenneth H. Mayer, Peter F. Wright, John C. Kappes, Christina Ochsenbauer, Charles R. Wira Jun 2012

Selective Impact Of Hiv Disease Progression On The Innate Immune System In The Human Female Reproductive Tract., Timothy Lahey, Mimi Ghosh, John V. Fahey, Zheng Sheng, Lucy R. Mukura, Yan Song, Susan Cu-Uvin, Kenneth H. Mayer, Peter F. Wright, John C. Kappes, Christina Ochsenbauer, Charles R. Wira

Epidemiology Faculty Publications

Background

We have previously demonstrated intrinsic anti-HIV activity in cervicovaginal lavage (CVL) from HIV-infected women with high CD4 counts and not on antiretroviral therapy. However, the impact of HIV disease progression on CVL innate immune responses has not been delineated.

Methods

CVL from 57 HIV-infected women not on antiretroviral therapy were collected by washing the cervicovaginal area with 10 ml of sterile normal saline. We characterized subject HIV disease progression by CD4 count strata: >500 cells/µl, 200–500 cells/µl, or <200 cells/µl of blood. To assess CVL anti-HIV activity, we incubated TZM-bl cells with HIV plus or minus CVL. Antimicrobials, cytokines, chemokines and anti-gp160 HIV IgG antibodies were measured by ELISA and Luminex.

Results

CVL exhibited broad anti-HIV activity against multiple laboratory-adapted and transmitted/founder (T/F) viruses, with anti-HIV activity ranging from 0 to 100% …


Analysis Of Dietary Patterns Over Freshman Year Of College, Chelsea Lofland Jun 2012

Analysis Of Dietary Patterns Over Freshman Year Of College, Chelsea Lofland

Statistics

This analysis is an investigation of changes in Cal Poly students’ eating habits over freshman year. The motivation behind this was an interest in college students’ lifestyles; college is the first time most students live on their own and it can be an important maturation period. College is stressful, exciting, liberating, and terrifying all at the same time. This distinctive life experience, along with my desire to handle big and messy data, led me to this research question.

The response variable analyzed was food consumption and the explanatory variables were: sex, race, quarter, food group, stress, exercise, BMI, sleep quality …


Change-Point Analysis Of Paired Allele-Specific Copy Number Variation Data, Yinglei Lai Jun 2012

Change-Point Analysis Of Paired Allele-Specific Copy Number Variation Data, Yinglei Lai

GW Biostatistics Center

The recent genome-wide allele-specific copy number variation data enable us to explore two types of genomic information including chromosomal genotype variations as well as DNA copy number variations. For a cancer study, it is common to collect data for paired normal and tumor samples. Then, two types of paired data can be obtained to study a disease subject. However, there is a lack of methods for a simultaneous analysis of these four sequences of data. In this study, we propose a statistical framework based on the change-point analysis approach. The validity and usefulness of our proposed statistical framework are demonstrated …


Characteristics Of Children With Type 1 Diabetes And Persistent Suboptimal Glycemic Control., Hyuntae Kim, Angelo Elmi, Celia L. Henderson, Fran R. Cogen, Paul B. Kaplowitz Jun 2012

Characteristics Of Children With Type 1 Diabetes And Persistent Suboptimal Glycemic Control., Hyuntae Kim, Angelo Elmi, Celia L. Henderson, Fran R. Cogen, Paul B. Kaplowitz

Epidemiology Faculty Publications

Objective: This study aims to determine the relationship between the duration of persistent poor glycemic control in type 1 diabetes mellitus (T1DM) children and the likelihood of subsequent improvement.

Methods: A retrospective cohort study was conducted on T1DM patients aged 6-18 years, followed for at least six visits at Children’s National Medical Center (Washington, DC) with at least one hemoglobin A1c (HbA1c) ≥10% after the first year since the initial visit (n=151). Medical records of patients with subsequently improved glycemic control were reviewed (n=39).

Results: Patients aged 12-18 years, females, and Medicaid patients were twice as likely to be in …


Estimating The Impact Of Community-Level Interventions: The Search Trial And Hiv Prevention In Sub-Saharan Africa, Laura Balzer, Maya Petersen, Joshua Schwab, Mark Van Der Laan May 2012

Estimating The Impact Of Community-Level Interventions: The Search Trial And Hiv Prevention In Sub-Saharan Africa, Laura Balzer, Maya Petersen, Joshua Schwab, Mark Van Der Laan

Laura B. Balzer

Evaluation of community level interventions to prevent HIV infection presents significant methodological challenges. Even when it is feasible to randomly assign a treatment versus control level of the intervention to each community in a sample, measurement of incident HIV infection remains difficult. In this talk we describe an experimental design developed for the SEARCH Trial, a large community randomized trial that will evaluate the impact of expanded treatment on incident HIV and other outcomes. Regular community-wide testing campaigns are conducted and a random sample of community members who fail to attend a campaign are tracked. The data generated by this …


Why Match In Individually And Cluster Randomized Trials?, Laura B. Balzer, Maya L. Petersen, Mark J. Van Der Laan May 2012

Why Match In Individually And Cluster Randomized Trials?, Laura B. Balzer, Maya L. Petersen, Mark J. Van Der Laan

Laura B. Balzer

The decision to match individuals or clusters in randomized trials is motivated by both practical and statistical concerns. Matching protects against chance imbalances in baseline covariate distributions and is thought to improve study credibility. Matching is also implemented to increase study power. This article compares the asymptotic efficiency of the pair-matched design, where units are matched on baseline covariates and the treatment randomized within pairs, to the independent design, where units are randomly paired and the treatment randomized within pairs. We focus on estimating the average treatment effect and use the efficient influence curve to understand the information provided by …