Open Access. Powered by Scholars. Published by Universities.®

Physical Sciences and Mathematics Commons

Open Access. Powered by Scholars. Published by Universities.®

Articles 1 - 30 of 48

Full-Text Articles in Physical Sciences and Mathematics

Teaching Of Biostatistics And Epidemiology In Medical Schools: How Do We Fare Compared With Developed Countries, Vijay Tiwari, Kuldeep Kumar, Sherin Raj Mar 2015

Teaching Of Biostatistics And Epidemiology In Medical Schools: How Do We Fare Compared With Developed Countries, Vijay Tiwari, Kuldeep Kumar, Sherin Raj

Kuldeep Kumar

Background Biostatistics is taught in almost all medical schools at the undergraduate and the postgraduate levels as a core course and is a prerequisite to epidemiology, public health and evidence-based medicine. However, it has to be taught in a different way in medical schools as compared with how it is taught to the students studying MSc (Biostatistics) or in the Statistics Department in universities. Objectives (1) To review the experience of teaching biostatistics in medical schools in India and compares the same with abroad (2) How best the curriculum can be designed as per the need of the medical students …


Promoting Similarity Of Model Sparsity Structures In Integrative Analysis Of Cancer Genetic Data, Shuangge Ma Dec 2014

Promoting Similarity Of Model Sparsity Structures In Integrative Analysis Of Cancer Genetic Data, Shuangge Ma

Shuangge Ma

In profiling studies, the analysis of a single dataset often leads to unsatisfactory results because of the small sample size. Multi-dataset analysis utilizes information across multiple independent datasets and outperforms single-dataset analysis. Among the available multi-dataset analysis methods, integrative analysis methods aggregate and analyze raw data and outperform meta-analysis methods, which analyze multiple datasets separately and then pool summary statistics. In this study, we conduct integrative analysis and marker selection under the heterogeneity structure, which allows different datasets to have overlapping but not necessarily identical sets of markers. Under certain scenarios, it is reasonable to expect some similarity of identified …


A Quantitative Paleoecological Approach To High-Resolution Cyclic And Event Stratigraphy: The Upper Ordovician Miamitown Shale In The Type Cincinnatian, Benjamin Dattilo Jul 2014

A Quantitative Paleoecological Approach To High-Resolution Cyclic And Event Stratigraphy: The Upper Ordovician Miamitown Shale In The Type Cincinnatian, Benjamin Dattilo

Benjamin F. Dattilo

No abstract provided.


Bias In Estimating The Causal Hazard Ratio Using Two-Stage Instrumental Variable Methods, Fei Wan, Dylan S. Small, Justin E. Bekelman, Nandita Mitra Dec 2013

Bias In Estimating The Causal Hazard Ratio Using Two-Stage Instrumental Variable Methods, Fei Wan, Dylan S. Small, Justin E. Bekelman, Nandita Mitra

fei wan

Two stage instrumental variable methods are commonly used to determine the causal effects of treatments on survival in the presence of measured and unmeasured confounding. Two stage residual inclusion (2SRI) has been the method of choice over two stage predictor substitution (2SPS) in clinical studies. We directly compare the bias in the causal hazard ratio estimated by these two methods. Under a principal stratification framework, we derive a closed form solution for asymptotic bias of the causal hazard ratio among compliers for both the 2SPS and 2SRI methods when survival time follows the Weibull distribution with random censoring. When there …


Integrative Analysis Of Prognosis Data On Multiple Cancer Subtypes, Shuangge Ma Dec 2012

Integrative Analysis Of Prognosis Data On Multiple Cancer Subtypes, Shuangge Ma

Shuangge Ma

In cancer research, profiling studies have been extensively conducted, searching for genes/SNPs associated with prognosis. Cancer is diverse. Examining similarity and difference in the genetic basis of multiple subtypes of the same cancer can lead to a better understanding of their connections and distinctions. Classic meta-analysis methods analyze each subtype separately and then compare analysis results across subtypes. Integrative analysis methods, in contrast, analyze the raw data on multiple subtypes simultaneously and can outperform meta-analysis methods. In this study, prognosis data on multiple subtypes of the same cancer are analyzed. An AFT (accelerated failure time) model is adopted to describe …


Why Match In Individually And Cluster Randomized Trials?, Laura Balzer, Maya Petersen, Mark Van Der Laan Apr 2012

Why Match In Individually And Cluster Randomized Trials?, Laura Balzer, Maya Petersen, Mark 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 thereby thought to improve study credibility. Matching is also implemented to increase study power. Analogue to Rose and van der Laan (2009), this article investigates the asymptotic efficiency of pair-matching individuals or clusters relative to not matching in randomized trials. We focus on estimating the average treatment effect. We use the efficient influence curve to understand the information provided by each design for estimation of the target causal parameter. Our approach …


An Annotated Bibliography Of Methods For Analyzing Correlated Categorical Data, Mark Ashby, John Neuhaus, Walter Hauck, Peter Bacchetti, David Heilbron, Nicholas Jewell, Mark Segal, Robert Fusaro Apr 2012

An Annotated Bibliography Of Methods For Analyzing Correlated Categorical Data, Mark Ashby, John Neuhaus, Walter Hauck, Peter Bacchetti, David Heilbron, Nicholas Jewell, Mark Segal, Robert Fusaro

Mark R Segal

This paper provides an annotated bibliography of over 100 articles concerning methods for analyzing correlated categorical response data. Most of the papers listed here concern categorical regression models and estimation, with particular emphasis on binary responses. The papers are classified by several characteristics which group them according to common themes. The bibliography serves as a reference of methods for analysts of correlated categorical data, as well as for persons interested in methodologic work in this active area of statistical research.


Diabetes Prediction In Pima Indians Using Ann And Statistical Techniques, Kuldeep Kumar, Ping Zhang Sep 2011

Diabetes Prediction In Pima Indians Using Ann And Statistical Techniques, Kuldeep Kumar, Ping Zhang

Kuldeep Kumar

Due to the fact that Pima Indian tribe has lived in the same location for an unmitigated number of years, a vast source of information of these people has been gained, which helps researchers for the study of diabetes and possible genetic factors of the disease. In this paper, we use Artificial Neural Network (ANN) and some statistical techniques for the prediction of diabetes. All the prediction models are evaluated with ROC curves.


Curriculum Vitae, Tatiyana V. Apanasovich Oct 2010

Curriculum Vitae, Tatiyana V. Apanasovich

Tatiyana V Apanasovich

No abstract provided.


Prognosis Of Acute Myocardial Infarction Complicated By Complete Heart Block (The Worcester Heart Attack Study), Robert Goldberg, Juan Zevallos, Jorge Yarzebski, Joseph Alpert, Joel Gore, Z. Chen, James Dalen Jul 2010

Prognosis Of Acute Myocardial Infarction Complicated By Complete Heart Block (The Worcester Heart Attack Study), Robert Goldberg, Juan Zevallos, Jorge Yarzebski, Joseph Alpert, Joel Gore, Z. Chen, James Dalen

Jorge L. Yarzebski

As part of a community-based study of patients hospitalized with acute myocardial infarction (AMI) in the Worcester, Massachusetts, metropolitan area, changes over time in the incidence rates of complete heart block (CHB) complicating AMI, and the prognostic impact of CHB on the in-hospital and long-term survival of these patients were examined. In all, 4,762 patients with validated AMI hospitalized at 16 hospitals in the Worcester metropolitan area during 1975, 1978, 1981, 1984, 1986 and 1988 constituted the study sample. The incidence rates of CHB complicating AMI remained relatively stable at 5.8% over the 13-year (1975 to 1988) period studied. The …


Long-Term Trends (1986-2003) In The Use Of Coronary Reperfusion Strategies In Patients Hospitalized With Acute Myocardial Infarction In Central Massachusetts, Robert J. Goldberg, Frederick A. Spencer, Joseph Okolo, Darleen M. Lessard, Jorge L. Yarzebski, Joel M. Gore Jul 2010

Long-Term Trends (1986-2003) In The Use Of Coronary Reperfusion Strategies In Patients Hospitalized With Acute Myocardial Infarction In Central Massachusetts, Robert J. Goldberg, Frederick A. Spencer, Joseph Okolo, Darleen M. Lessard, Jorge L. Yarzebski, Joel M. Gore

Jorge L. Yarzebski

BACKGROUND: The objectives of our study were to examine long-term (1986-2003) trends in the use of percutaneous coronary interventions (PCI) and thrombolytic therapy in the management of patients hospitalized at all Central Massachusetts medical centers with acute myocardial infarction (AMI). Our secondary study goal was to examine factors associated with use of these coronary reperfusion strategies. Limited contemporary data are available about changing trends in the use of coronary reperfusion strategies, particularly from a population-based perspective. METHODS: The sample consisted of 9422 greater Worcester (MA) residents hospitalized with AMI at all metropolitan Worcester medical centers in 10 annual periods between …


A Community-Wide Perspective Of Gender Differences And Temporal Trends In The Use Of Diagnostic And Revascularization Procedures For Acute Myocardial Infarction, David Chiriboga, Jorge Yarzebski, Robert Goldberg, Z. Chen, Jerry Gurwitz, Joel Gore, Joseph Alpert, James Dalen Jul 2010

A Community-Wide Perspective Of Gender Differences And Temporal Trends In The Use Of Diagnostic And Revascularization Procedures For Acute Myocardial Infarction, David Chiriboga, Jorge Yarzebski, Robert Goldberg, Z. Chen, Jerry Gurwitz, Joel Gore, Joseph Alpert, James Dalen

Jorge L. Yarzebski

This study compares the overall use, as well as temporal trends, of various diagnostic and revascularization procedures for acute myocardial infarction (AMI) in men and women. The study sample comprised a total of 2,924 men and 1,838 women with validated AMI admitted to any of the 16 teaching and community hospitals in the Worcester, Massachusetts, metropolitan area during 1975, 1978, 1981, 1984, 1986 and 1988. During the period under study there was a significant increase in use of each of the examined procedures during hospitalization for AMI in both men and women. Increasing use of multiple procedures was also seen …


Temporal Trends And Factors Associated With Extent Of Delay To Hospital Arrival In Patients With Acute Myocardial Infarction: The Worcester Heart Attack Study, Jorge Yarzebski, Robert Goldberg, Joel Gore, Joseph Alpert Jul 2010

Temporal Trends And Factors Associated With Extent Of Delay To Hospital Arrival In Patients With Acute Myocardial Infarction: The Worcester Heart Attack Study, Jorge Yarzebski, Robert Goldberg, Joel Gore, Joseph Alpert

Jorge L. Yarzebski

Factors associated with delay to hospital arrival after the onset of symptoms suggestive of acute myocardial infarction (AMI) were examined in the late 1960s and 1970s, but recent data concerning these characteristics are limited. The purpose of the present study was to examine overall and temporal distributions of the extent of patients' delay from the time of onset of AMI symptoms to hospital arrival and factors associated with delay in seeking medical care from a multihospital, population-based perspective. Review of medical records was undertaken of patients hospitalized with a discharge diagnosis of AMI in 16 teaching and community hospitals in …


Patient Delay And Receipt Of Thrombolytic Therapy Among Patients With Acute Myocardial Infarction From A Community-Wide Perspective, Robert Goldberg, Jerry Gurwitz, Jorge Yarzebski, J. Landon, Joel Gore, Joseph Alpert, P. Dalen, James Dalen Jul 2010

Patient Delay And Receipt Of Thrombolytic Therapy Among Patients With Acute Myocardial Infarction From A Community-Wide Perspective, Robert Goldberg, Jerry Gurwitz, Jorge Yarzebski, J. Landon, Joel Gore, Joseph Alpert, P. Dalen, James Dalen

Jorge L. Yarzebski

The duration of patient delay from the time of onset of symptoms of acute myocardial infarction (AMI) to hospital presentation, and the relation of delay time and various patient characteristics to receipt of thrombolytic therapy were examined as part of a community-based study of patients hospitalized with AMI in the Worcester, Massachusetts, metropolitan area. In all, 800 patients with validated AMI hospitalized at 16 hospitals in the Worcester metropolitan area in 1986 and 1988 constituted the study sample. Patients delayed on average 4 hours between noting symptoms suggestive of AMI and presenting to area-wide emergency departments with no significant change …


Identification Of Cancer-Associated Gene Pathways From Analysis Of Expression Data, Shuangge Ma Aug 2009

Identification Of Cancer-Associated Gene Pathways From Analysis Of Expression Data, Shuangge Ma

Shuangge Ma

No abstract provided.


Lecture 5, Shuangge Ma Jun 2009

Lecture 5, Shuangge Ma

Shuangge Ma

No abstract provided.


Final Project, Shuangge Ma Jun 2009

Final Project, Shuangge Ma

Shuangge Ma

No abstract provided.


Lecture 4, Shuangge Ma Jun 2009

Lecture 4, Shuangge Ma

Shuangge Ma

No abstract provided.


Lecture 4, Shuangge Ma Jun 2009

Lecture 4, Shuangge Ma

Shuangge Ma

No abstract provided.


Computer Intensive Methods Lecture 13, Shuangge Ma Jun 2009

Computer Intensive Methods Lecture 13, Shuangge Ma

Shuangge Ma

No abstract provided.


Final Project (Description), Shuangge Ma Jun 2009

Final Project (Description), Shuangge Ma

Shuangge Ma

No abstract provided.


Final Project (Data), Shuangge Ma Jun 2009

Final Project (Data), Shuangge Ma

Shuangge Ma

No abstract provided.


Lecture 3, Shuangge Ma Jun 2009

Lecture 3, Shuangge Ma

Shuangge Ma

No abstract provided.


Lecture 2, Shuangge Ma Jun 2009

Lecture 2, Shuangge Ma

Shuangge Ma

No abstract provided.


Reference: Multiple Imputation, Shuangge Ma Jun 2009

Reference: Multiple Imputation, Shuangge Ma

Shuangge Ma

No abstract provided.


Reference: Weighted Bootstrap, Shuangge Ma Jun 2009

Reference: Weighted Bootstrap, Shuangge Ma

Shuangge Ma

No abstract provided.


Computer Intensive Methods Lecture 9, Shuangge Ma Jun 2009

Computer Intensive Methods Lecture 9, Shuangge Ma

Shuangge Ma

No abstract provided.


Computer Intensive Methods Lecture 8, Shuangge Ma Jun 2009

Computer Intensive Methods Lecture 8, Shuangge Ma

Shuangge Ma

No abstract provided.


Reference: Counter Examples [Bootstrap], Shuangge Ma Jun 2009

Reference: Counter Examples [Bootstrap], Shuangge Ma

Shuangge Ma

No abstract provided.


Computer Intensive Methods Lecture 7 (Lab 2), Shuangge Ma Jun 2009

Computer Intensive Methods Lecture 7 (Lab 2), Shuangge Ma

Shuangge Ma

No abstract provided.