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A Ten-Year Comparison Of Women Authorship In U.S. Dermatology Literature, 1999 Vs. 2009, Shali Zhang, Ha-Young Kim, Rachel E.S. Hill, Emir Veledar, Suephy C. Chen 2018 Emory University

A Ten-Year Comparison Of Women Authorship In U.S. Dermatology Literature, 1999 Vs. 2009, Shali Zhang, Ha-Young Kim, Rachel E.S. Hill, Emir Veledar, Suephy C. Chen

Emir Veledar

Women are entering medicine at increasing rates, particularly in dermatology. In this study, we compared women’s influence and status in academic dermatology with that of men by examining authorship roles in peer-reviewed dermatology literature.Weexamined the literature in2009 and compared that to10 years prior (1999).Atotal of 1399 articles were reviewed, 594 of whichmet study criteria andwere included in statistical analysis. There was amarked increase in senior female authorship over a decade (22% vs. 38%, p b 0.001). Female first authorship increased as well (41% vs. 51%, p b 0.001). In contrast, changes in male senior and ...


Phase Ii Adaptive Enrichment Design To Determine The Population To Enroll In Phase Iii Trials, By Selecting Thresholds For Baseline Disease Severity, Yu Du, Gary L. Rosner, Michael Rosenblum 2018 Johns Hopkins Bloomberg School of Public Health, Department of Biostatistics

Phase Ii Adaptive Enrichment Design To Determine The Population To Enroll In Phase Iii Trials, By Selecting Thresholds For Baseline Disease Severity, Yu Du, Gary L. Rosner, Michael Rosenblum

Johns Hopkins University, Dept. of Biostatistics Working Papers

We propose and evaluate a two-stage, phase 2, adaptive clinical trial design. Its goal is to determine whether future phase 3 (confirmatory) trials should be conducted, and if so, which population should be enrolled. The population selected for phase 3 enrollment is defined in terms of a disease severity score measured at baseline. We optimize the phase 2 trial design and analysis in a decision theory framework. Our utility function represents a combination of the cost of conducting phase 3 trials and, if the phase 3 trials are successful, the improved health of the future population minus the cost of ...


Optimized Adaptive Enrichment Designs For Multi-Arm Trials: Learning Which Subpopulations Benefit From Different Treatments, Jon Arni Steingrimsson, Joshua Betz, Tiachen Qian, Michael Rosenblum 2018 Department of Biostatistics, Brown School of Public Health

Optimized Adaptive Enrichment Designs For Multi-Arm Trials: Learning Which Subpopulations Benefit From Different Treatments, Jon Arni Steingrimsson, Joshua Betz, Tiachen Qian, Michael Rosenblum

Johns Hopkins University, Dept. of Biostatistics Working Papers

We consider the problem of designing a randomized trial for comparing two treatments versus a common control in two disjoint subpopulations. The subpopulations could be defined in terms of a biomarker or disease severity measured at baseline. The goal is to determine which treatments benefit which subpopulations. We develop a new class of adaptive enrichment designs tailored to solving this problem. Adaptive enrichment designs involve a preplanned rule for modifying enrollment based on accruing data in an ongoing trial. The proposed designs have preplanned rules for stopping accrual of treatment by subpopulation combinations, either for efficacy or futility. The motivation ...


Big Data And Parkinson’S Disease: Exploration, Analyses, And Data Challenges, Mahalakshmi SenthilarumugamVeilukandammal, Sree Nilakanta, Baskar Ganapathysubramanian, Vellareddy Anantharam, Anumantha Kanthasamy, Auriel A. Willette 2018 Iowa State University

Big Data And Parkinson’S Disease: Exploration, Analyses, And Data Challenges, Mahalakshmi Senthilarumugamveilukandammal, Sree Nilakanta, Baskar Ganapathysubramanian, Vellareddy Anantharam, Anumantha Kanthasamy, Auriel A. Willette

Mechanical Engineering Conference Presentations, Papers, and Proceedings

In healthcare, a tremendous amount of clinical and laboratory tests, imaging, prescription and medication data are being collected. Big data analytics on these data aim at early detection of disease which will help in developing preventive measures and in improving patient care. Parkinson disease is the second-most common neurodegenerative disorder in the United States. To find a cure for Parkinson's disease biological, clinical and behavioral data of different cohorts are collected, managed and propagated through Parkinson’s Progression Markers Initiative (PPMI). Applying big data technology to this data will lead to the identification of the potential biomarkers of Parkinson ...


Bivariate Generalization Of The Time-To-Event Conditional Reassessment Method With A Novel Adaptive Randomization Method, Donglin Yan 2018 University of Kentucky

Bivariate Generalization Of The Time-To-Event Conditional Reassessment Method With A Novel Adaptive Randomization Method, Donglin Yan

Theses and Dissertations--Epidemiology and Biostatistics

Phase I clinical trials in oncology aim to evaluate the toxicity risk of new therapies and identify a safe but also effective dose for future studies. Traditional Phase I trials of chemotherapies focus on estimating the maximum tolerated dose (MTD). The rationale for finding the MTD is that better therapeutic effects are expected at higher dose levels as long as the risk of severe toxicity is acceptable. With the advent of a new generation of cancer treatments such as the molecularly targeted agents (MTAs) and immunotherapies, higher dose levels no longer guarantee increased therapeutic effects, and the focus has shifted ...


Cross-Sectional Versus Longitudinal Designs For Function Estimation, With An Application To Cerebral Cortex Development, Philip T. Reiss 2017 New York University School of Medicine

Cross-Sectional Versus Longitudinal Designs For Function Estimation, With An Application To Cerebral Cortex Development, Philip T. Reiss

Philip T. Reiss

Motivated by studies of the development of the human cerebral cortex, we consider
the estimation of a mean growth trajectory and the relative merits of cross-sectional
and longitudinal data for that task. We define a class of relative efficiencies that
compare function estimates in terms of aggregate variance of a parametric function
estimate. These generalize the classical design effect for estimating a scalar with
cross-sectional versus longitudinal data, and in particular cases are shown to be
bounded above by it. Turning to nonparametric function estimation, we find that a
longitudinal fits may tend to have higher aggregate variance than cross-sectional ...


Reassessment Of The Red Drum Stock In Mississippi Coastal Waters: The Role Of Ages 3-5 Year-Class Fish, Emily Satterfield 2017 The University of Southern Mississippi

Reassessment Of The Red Drum Stock In Mississippi Coastal Waters: The Role Of Ages 3-5 Year-Class Fish, Emily Satterfield

Master's Theses

Red Drum, Sciaenops ocellatus, are highly sought after by sport fishermen in Mississippi coastal waters. In 2016, Mississippi anglers made over 180,000 fishing trips targeting Red Drum, making it the second most targeted marine species. The current Fishery Management Plan of the Gulf of Mexico Fishery Management Council, prohibits harvest of Red Drum in federal waters. Monitoring of the stock in Mississippi state waters occurs at sites that are almost exclusively estuarine, using gear types selective for juvenile fish. Additional samples come from the for-hire-industry that typically targets larger Red Drum. This project’s goal was to target age ...


Functional Data Analysis Methods For Predicting Disease Status., Sarah Kendrick 2017 University of Louisville

Functional Data Analysis Methods For Predicting Disease Status., Sarah Kendrick

Electronic Theses and Dissertations

Introduction: Differential scanning calorimetry (DSC) is used to determine thermally-induced conformational changes of biomolecules within a blood plasma sample. Recent research has indicated that DSC curves (or thermograms) may have different characteristics based on disease status and, thus, may be useful as a monitoring and diagnostic tool for some diseases. Since thermograms are curves measured over a range of temperature values, they are often considered as functional data. In this dissertation we propose and apply functional data analysis (FDA) techniques to analyze DSC data from the Lupus Family Registry and Repository (LFRR). The aim is to develop FDA methods to ...


Sample Size Calculations And Normalization Methods For Rna-Seq Data., Xiaohong Li 2017 University of Louisville

Sample Size Calculations And Normalization Methods For Rna-Seq Data., Xiaohong Li

Electronic Theses and Dissertations

High-throughput RNA sequencing (RNA-seq) has become the preferred choice for transcriptomics and gene expression studies. With the rapid growth of RNA-seq applications, sample size calculation methods for RNA-seq experiment design and data normalization methods for DEG analysis are important issues to be explored and discussed. The underlying theme of this dissertation is to develop novel sample size calculation methods in RNA-seq experiment design using test statistics. I have also proposed two novel normalization methods for analysis of RNA-seq data. In chapter one, I present the test statistical methods including Wald’s test, log-transformed Wald’s test and likelihood ratio test ...


Clinical Evaluation Of The Cepheid Xpert® Tv Assay For Detection Of Trichomonas Vaginalis With Prospectively Collected Female And Male Specimens., Jane R Schwebke, C A Gaydos, T Davis, J Marrazzo, D Furgerson, S N Taylor, B Smith, L H Bachmann, R Ackerman, T Spurrell, D Ferris, C A Burnham, H Reno, J Lebed, D Eisenberg, P Kerndt, S Philip, J Jordan, N Quigley 2017 George Washington University

Clinical Evaluation Of The Cepheid Xpert® Tv Assay For Detection Of Trichomonas Vaginalis With Prospectively Collected Female And Male Specimens., Jane R Schwebke, C A Gaydos, T Davis, J Marrazzo, D Furgerson, S N Taylor, B Smith, L H Bachmann, R Ackerman, T Spurrell, D Ferris, C A Burnham, H Reno, J Lebed, D Eisenberg, P Kerndt, S Philip, J Jordan, N Quigley

Epidemiology and Biostatistics Faculty Publications

Trichomoniasis is the most prevalent curable sexually transmitted disease (STD). It has been associated with preterm birth and acquisition/transmission of HIV. Recently, nucleic acid amplification tests (NAAT) have been FDA-cleared in the United States for detection of Trichomonas vaginalis (TV) in specimens from both women and men. This current study reports the results of a multicenter study recently conducted using the Xpert TV Assay to test specimens from both men and women. On-demand results were available in as little as 40 minutes for positive specimens. A total of 1867 women and 4791 men were eligible for inclusion in the ...


Data-Adaptive Kernel Support Vector Machine, Xin Liu 2017 The University of Western Ontario

Data-Adaptive Kernel Support Vector Machine, Xin Liu

Electronic Thesis and Dissertation Repository

In this thesis, we propose the data-adaptive kernel Support Vector Machine (SVM), a new method with a data-driven scaling kernel function based on real data sets. This two-stage approach of kernel function scaling can enhance the accuracy of a support vector machine, especially when the data are imbalanced. Followed by the standard SVM procedure in the first stage, the proposed method locally adapts the kernel function to data locations based on the skewness of the class outcomes. In the second stage, the decision rule is constructed with the data-adaptive kernel function and is used as the classifier. This process enlarges ...


Using Multilevel Outcomes To Construct And Select Biomarker Combinations For Single-Level Prediction, Allison Meisner, Chirag R. Parikh, Kathleen F. Kerr 2017 University of Washington, Seattle

Using Multilevel Outcomes To Construct And Select Biomarker Combinations For Single-Level Prediction, Allison Meisner, Chirag R. Parikh, Kathleen F. Kerr

UW Biostatistics Working Paper Series

Biomarker studies may involve a multilevel outcome, such as no, mild, or severe disease. There is often interest in predicting one particular level of the outcome due to its clinical significance. The standard approach to constructing biomarker combinations in this context involves dichotomizing the outcome and using a binary logistic regression model. We assessed whether information can be usefully gained from instead using more sophisticated regression methods. Furthermore, it is often necessary to select among several candidate biomarker combinations. One strategy involves selecting a combination on the basis of its ability to predict the outcome level of interest. We propose ...


Constructing A Confidence Interval For The Fraction Who Benefit From Treatment, Using Randomized Trial Data, Emily J. Huang, Ethan X. Fang, Daniel F. Hanley, Michael Rosenblum 2017 Johns Hopkins University School of Public Health, Department of Biostatistics

Constructing A Confidence Interval For The Fraction Who Benefit From Treatment, Using Randomized Trial Data, Emily J. Huang, Ethan X. Fang, Daniel F. Hanley, Michael Rosenblum

Johns Hopkins University, Dept. of Biostatistics Working Papers

The fraction who benefit from treatment is the proportion of patients whose potential outcome under treatment is better than that under control. Inference on this parameter is challenging since it is only partially identifiable, even in our context of a randomized trial. We propose a new method for constructing a confidence interval for the fraction, when the outcome is ordinal or binary. Our confidence interval procedure is pointwise consistent. It does not require any assumptions about the joint distribution of the potential outcomes, although it has the flexibility to incorporate various user-defined assumptions. Unlike existing confidence interval methods for partially ...


Correction Of Verification Bias By Application Of Homogeneous Log-Linear Models For A Single Scale Binary Diagnostic Test, Haresh D. Rochani, Hani M. Samawi, Robert L. Vogel, Jingjing Yin 2017 Georgia Southern University

Correction Of Verification Bias By Application Of Homogeneous Log-Linear Models For A Single Scale Binary Diagnostic Test, Haresh D. Rochani, Hani M. Samawi, Robert L. Vogel, Jingjing Yin

Robert L. Vogel

In patient management and control of many infectious diseases it is very crucial to have accurate diagnostic test. The test/procedure that determines the true disease status without an error is referred to as gold standard test. Even when a gold standard exist, it is extremely difficult to verify each patient due to the issues of cost-effectiveness and invasive nature of the procedures. In practice some of the patients with test results are not selected for verification of the disease status which results into a verification bias for diagnostic tests. The ability of the diagnostic tests to correctly identify the ...


Persistent Organic Pollutants And Mortality In The United States, Nhanes 1999-2011., Kristiann Fry, Melinda C Power 2017 George Washington University

Persistent Organic Pollutants And Mortality In The United States, Nhanes 1999-2011., Kristiann Fry, Melinda C Power

Epidemiology and Biostatistics Faculty Publications

Background

Persistent organic pollutants (POPs) are environmentally and biologically persistent chemicals that include polybrominated diphenyl ethers (PBDEs), per- and polyfluoroalkyl substances (PFASs), polychlorinated biphenyls (PCBs), and organochlorine (OC) pesticides. Currently, data on the associations between exposure to POPs and the risk of mortality in the U.S. population is limited.

Our objective was to determine if higher exposure to POPs is associated with greater risk of all-cause, cancer, heart/cerebrovascular disease, or other-cause mortality.

Methods

Analyses included participants aged 60 years and older from the 1999–2006 National Health and Nutrition Examination Surveys (NHANES). We included 483 participants for analyses ...


An Optimal Nonparametric Test Of Symmetry Based On The Overlapping Coefficient Using An Extreme Ranked Set Sample: Application To Noninvasive Measurement Of Cardiac Output By Electrical Velocimetry In Neonates, Hani M. Samawi, Robert L. Vogel, Barbara Weaver, Joseph M. Van De Water 2017 Georgia Southern University

An Optimal Nonparametric Test Of Symmetry Based On The Overlapping Coefficient Using An Extreme Ranked Set Sample: Application To Noninvasive Measurement Of Cardiac Output By Electrical Velocimetry In Neonates, Hani M. Samawi, Robert L. Vogel, Barbara Weaver, Joseph M. Van De Water

Hani M. Samawi

In this paper we provide a more efficient nonparametric test of symmetry based on the empirical overlap coefficient using kernel density estimation applied to an extreme ranked set sample. Our investigation reveals that our proposed test of symmetry is more powerful than all available tests of symmetry. Intensive simulation is conducted to examine the power of the proposed test. An illustration is provided using cardiac output and body weight of neonates in a neonatal intensive care unit.


Correction Of Verification Bias By Application Of Homogeneous Log-Linear Models For A Single Scale Binary Diagnostic Test, Haresh D. Rochani, Hani M. Samawi, Robert L. Vogel, Jingjing Yin 2017 Georgia Southern University

Correction Of Verification Bias By Application Of Homogeneous Log-Linear Models For A Single Scale Binary Diagnostic Test, Haresh D. Rochani, Hani M. Samawi, Robert L. Vogel, Jingjing Yin

Hani M. Samawi

In patient management and control of many infectious diseases it is very crucial to have accurate diagnostic test. The test/procedure that determines the true disease status without an error is referred to as gold standard test. Even when a gold standard exist, it is extremely difficult to verify each patient due to the issues of cost-effectiveness and invasive nature of the procedures. In practice some of the patients with test results are not selected for verification of the disease status which results into a verification bias for diagnostic tests. The ability of the diagnostic tests to correctly identify the ...


On The Estimation Of Penetrance In The Presence Of Competing Risks With Family Data, Daniel Prawira 2017 The University of Western Ontario

On The Estimation Of Penetrance In The Presence Of Competing Risks With Family Data, Daniel Prawira

Electronic Thesis and Dissertation Repository

In family studies, we are interested in estimating the penetrance function of the event of interest in the presence of competing risks. Failure to account for competing risks may lead to bias in the estimation of the penetrance function. In this thesis, three statistical challenges are addressed: clustering, missing data, and competing risks. We proposed the cause-specific model with shared frailty and ascertainment correction to account for clustering and competing risks along with ascertainment of families into study. Multiple imputation is used to account for missing data. The simulation study showed good performance of our proposed model in estimating the ...


Correction Of Verification Bias By Application Of Homogeneous Log-Linear Models For A Single Scale Binary Diagnostic Test, Haresh D. Rochani, Hani M. Samawi, Robert L. Vogel, Jingjing Yin 2017 Georgia Southern University

Correction Of Verification Bias By Application Of Homogeneous Log-Linear Models For A Single Scale Binary Diagnostic Test, Haresh D. Rochani, Hani M. Samawi, Robert L. Vogel, Jingjing Yin

Haresh Rochani

In patient management and control of many infectious diseases it is very crucial to have accurate diagnostic test. The test/procedure that determines the true disease status without an error is referred to as gold standard test. Even when a gold standard exist, it is extremely difficult to verify each patient due to the issues of cost-effectiveness and invasive nature of the procedures. In practice some of the patients with test results are not selected for verification of the disease status which results into a verification bias for diagnostic tests. The ability of the diagnostic tests to correctly identify the ...


Comparison Of Adaptive Randomized Trial Designs For Time-To-Event Outcomes That Expand Versus Restrict Enrollment Criteria, To Test Non-Inferiority, Josh Betz, Jon Arni Steingrimsson, Tianchen Qian, Michael Rosenblum 2017 Johns Hopkins Bloomberg School of Public Health, Department of Biostatistics

Comparison Of Adaptive Randomized Trial Designs For Time-To-Event Outcomes That Expand Versus Restrict Enrollment Criteria, To Test Non-Inferiority, Josh Betz, Jon Arni Steingrimsson, Tianchen Qian, Michael Rosenblum

Johns Hopkins University, Dept. of Biostatistics Working Papers

Adaptive enrichment designs involve preplanned rules for modifying patient enrollment criteria based on data accrued in an ongoing trial. These designs may be useful when it is suspected that a subpopulation, e.g., defined by a biomarker or risk score measured at baseline, may benefit more from treatment than the complementary subpopulation. We compare two types of such designs, for the case of two subpopulations that partition the overall population. The first type starts by enrolling the subpopulation where it is suspected the new treatment is most likely to work, and then may expand inclusion criteria if there is early ...


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