Digital Commons Network^™

Analysis Of Longitudinal Marginal Structural Models , Jennifer F. Bryan, Zhuo Yu, Mark J. Van Der Laan

U.C. Berkeley Division of Biostatistics Working Paper Series

In this article we construct and study estimators of the causal effect of a time-dependent treatment on survival in longitudinal studies. We employ a particular marginal structural model (MSM), and follow a general methodology for constructing estimating functions in censored data models. The inverse probability of treatment weighted (IPTW) estimator is used as an initial estimator and the corresponding treatment-orthogonalized, one-step estimator is consistent and asymptotically linear when the treatment mechanism is consistently estimated. We extend these methods to handle informative censoring. A simulation study demonstrates that the the treatment-orthogonalized, one-step estimator is superior to the IPTW estimator in terms …

A Reduced Model Clarifies The Role Of Feedback Loops And Time Delays In The Drosophila Circadian Oscillator, Paul Smolen, Douglas A. Baxter, John H. Byrne

Faculty, Staff and Student Publications

Although several detailed models of molecular processes essential for circadian oscillations have been developed, their complexity makes intuitive understanding of the oscillation mechanism difficult. The goal of the present study was to reduce a previously developed, detailed model to a minimal representation of the transcriptional regulation essential for circadian rhythmicity in Drosophila. The reduced model contains only two differential equations, each with time delays. A negative feedback loop is included, in which PER protein represses per transcription by binding the dCLOCK transcription factor. A positive feedback loop is also included, in which dCLOCK indirectly enhances its own formation. The model …

Mining Of Correlated Rules In Genome Sequences, L. Lin, L. Wong, Tze-Yun Leong, P. S. Lai

Research Collection School Of Computing and Information Systems

With the huge amount of data collected by scientists in the molecular genetics community in recent years, there exists a need to develop some novel algorithms based on existing data mining techniques to discover useful information from genome databases. We propose an algorithm that integrates the statistical method, association rule mining, and classification rule mining in the discovery of allelic combinations of genes that are peculiar to certain phenotypes of diseased patients.

An Empirical Study Of Marginal Structural Models For Time-Independent Treatment, Tanya A. Henneman, Mark J. Van Der Laan

U.C. Berkeley Division of Biostatistics Working Paper Series

In non-randomized treatment studies a significant problem for statisticians is determining how best to adjust for confounders. Marginal structural models (MSMs) and inverse probability of treatment weighted (IPTW) estimators are useful in analyzing the causal effect of treatment in observational studies. Given an IPTW estimator a doubly robust augmented IPTW (AIPTW) estimator orthogonalizes it resulting in a more e±cient estimator than the IPTW estimator. One purpose of this paper is to make a practical comparison between the IPTW estimator and the doubly robust AIPTW estimator via a series of Monte- Carlo simulations. We also consider the selection of the optimal …

Santa Clara Magazine, Volume 44 Number 2, Fall 2002, Santa Clara University

Santa Clara Magazine

6 - INSTITUTE ON GLOBALIZATION By SCM Staff. For the academic year 2002-03, SCU will focus on globalization and how it is shaping our world.

12 - TOUGH TALK By Dale Larson. End-of-life conversations can help us cope with the loss· of a loved one.

16 - BUILDING CHARACTER By Miriam Schulman . Alumni are helping troubled kids make better choices using a program developed by SCU's Markkula Center for Applied Ethics.

2002 Scholars And Artists Bibliography, Michael Schwartz Library, Cleveland State University, Friends Of The Michael Schwartz Library

Scholars and Artists Bibliographies

This bibliography was created for the annual Friends of the Michael Schwartz Library Scholars and Artists Reception, recognizing scholarly and creative achievements of Cleveland State University faculty, staff and emeriti

Inside Unlv, Diane Russell, Gian Galassi, Cate Weeks

Inside UNLV

No abstract provided.

Training And Performance Self-Efficacy, Affect, And Performance In Wheelchair Road Racers, Jeffrey J. Martin

Kinesiology, Health and Sport Studies

In the current study, social cognitive theory was examined with athletes with disabilities. More specifically, hierarchical and self-regulatory performance self-efficacy, self-regulatory training self-efficacy, outcome confidence, and affect were examined with wheelchair road racers (N = 51). In accordance with social cognitive theory, moderate to strong significant relationships among 3 types of self-efficacy and outcome confidence were found (rs = .41 - .78). All forms of self-efficacy and positive affect (rs = .39 - .56) were also related providing additional support to social cognitive theory and the important relationships among training and performance related efficacy and affect in …

Yet Another Algorithm For Pitch Tracking (Yaapt), Kavita Kasi

Electrical & Computer Engineering Theses & Dissertations

This thesis presents a pitch detection algorithm that is extremely robust for both high quality and telephone speech. The kernel method for this algorithm is the Normalized Cross Correlation (NCCF) reported by David Talkin [16]. Major innovations include: processing of the original acoustic signal and a nonlinearly processed version of the signal to partially restore very weak F0 components; intelligent peak picking to select multiple F0 candidates and assign merit factors; and, incorporation of highly robust pitch contours obtained from smoothed versions of low frequency portions of spectrograms. Dynamic programming is used to find the ''best" pitch track among all …

The Analysis Of Placement Values For Evaluating Discriminatory Measures, Margaret S. Pepe, Tianxi Cai

UW Biostatistics Working Paper Series

The idea of using measurements such as biomarkers, clinical data, or molecular biology assays for classification and prediction is popular in modern medicine. The scientific evaluation of such measures includes assessing the accuracy with which they predict the outcome of interest. Receiver operating characteristic curves are commonly used for evaluating the accuracy of diagnostic tests. They can be applied more broadly, indeed to any problem involving classification to two states or populations (D = 0 or D = 1). We show that the ROC curve can be interpreted as a cumulative distribution function for the discriminatory measure Y in the …

Case-Control Current Status Data, Nicholas P. Jewell, Mark J. Van Der Laan

U.C. Berkeley Division of Biostatistics Working Paper Series

Current status observation on survival times has recently been widely studied. An extreme form of interval censoring, this data structure refers to situations where the only available information on a survival random variable, T, is whether or not T exceeds a random independent monitoring time C, a binary random variable, Y. To date, nonparametric analyses of current status data have assumed the availability of i.i.d. random samples of the random variable (Y, C), or a similar random sample at each of a set of fixed monitoring times. In many situations, it is useful to consider a case-control sampling scheme. Here, …

Current Status Data: Review, Recent Developments And Open Problems, Nicholas P. Jewell, Mark J. Van Der Laan

U.C. Berkeley Division of Biostatistics Working Paper Series

Researchers working with survival data are by now adept at handling issues associated with incomplete data, particular those associated with various forms of censoring. An extreme form of interval censoring, known as current status observation, refers to situations where the only available information on a survival random variable T is whether or not T exceeds a random independent monitoring time C. This article contains a brief review of the extensive literature on the analysis of current status data, discussing the implications of response-based sampling on these methods. The majority of the paper introduces some recent extensions of these ideas to …

Inside Unlv, Diane Russell

Inside UNLV

No abstract provided.

Synthesis And Characterization Of Hydroxyapatite-Collagen Biocomposite Materials, Vuk Uskoković, Nenad Ignjatović, Nadejda Petranović

Pharmacy Faculty Articles and Research

Hydroxyapatite-collagen composite is a prosperous biomaterial in reconstructive surgery for the reparation of defects within human hard tissue. Within this research, three-dimensional blocks of HAp/collagen composite biomaterial were synthesized by homogenizing the HAp/collagen mixture by cold and hot (T=60oC) pressing (P=49 MPa). The changes in the system were followed by using thermal analysis (DSC & TGA), FT-IR spectroscopy and scanning electron microscopy (SEM). The identification and kinetic analysis of appearing phase transition were done. FT-IR spectrum of the biocomposite shows that neither cold nor hot pressing had significant influence on the individual components of the composite. SEM of the fracture …

Estimating Population Numbers Of Black Bears (Ursus Americanus) In Eastern Kentucky Using Microsatellite Analysis, Kelly Vowels

Masters Theses & Specialist Projects

Black bears (Ursus americanus) occur sporadically in eastern Kentucky, and there is some evidence that a breeding population exists. In order to establish management practices to enhance the black bear population in Kentucky, information about this population is needed. However, until recently, no population size estimate has been available. Gathering information on black bears is difficult because black bears are elusive animals. The development of new molecular methods has made it easier to track and gather information on black bear populations, including estimates of population size. Molecular markers are particularly useful in that they do not require physical contact with …

A Correlational Analysis Of Anthropometric Measures And Selected Blood, Immune And Endocrine Indices In Adult Males, Janet Tracey Peterson

Loma Linda University Electronic Theses, Dissertations & Projects

Over the past few decades it has become apparent that increased body weight, specifically body fat, coupled with a sedentary lifestyle is associated with an increased risk for chronic disorders such as cardiovascular disease and diabetes. Researchers are now re-directing their focus on determining the cause of these relationships from an epidemiological view to a more biological or physiological standpoint. The purpose of this cross sectional study was to examine associations among obesity, physical activity and select immune, endocrine and metabolic parameters identified as risk factors for several chronic conditions. Ninety-one healthy males between the ages of 19 and 45 …

Dose Coefficient (Dc) Methodology Report, John P. Shanahan, Phillip W. Patton, Mark Rudin

Transmutation Sciences Physics (TRP)

The purpose of this report is to present the methodology developed to calculate internal and external dose coefficients for radionuclides produced in the spallation process. Much of the information regarding computer codes in this report comes from various technical manuals and professional papers. References are provided at the beginning of each section for documentation and for the user who requires more specific information. The report also includes the results of applying the methodology to determine dose coefficients for five radionuclides. This effort identified potential areas of concern that will need to be addressed when the methodology is used in the …

Il-10 And Alveolar Bone Loss, Abdulaziz Saud Al-Rasheed

Loma Linda University Electronic Theses, Dissertations & Projects

Interleukin-10 (IL-10) is a cytokine with anti-inflammatory activities. IL-10 knockout (KO) mice exhibit severe intestinal inflammation in the presence of normal gut flora. We hypothesized that IL-10 KO mice would also be susceptible to inflammatory periodontal disease resulting in alveolar bone loss (ABL). The purpose of this study was to compare naturally occurring ABL in IL-10 KO and wild type (WT) mice. Twelve IL-10 KO and 12 WT mice, age-(7 months) and sex-(male) matched, were used. Half of the mice were on 129/SvEv and half on C57BL/6J background. Animal heads were defleshed and treated to remove all organic material. ABL …

Vital Signs, Fall 2002, Boonshoft School Of Medicine

Vital Signs

A twenty-seven page newsletter created by the Boonshoft School of Medicine to document the current affairs of the school. This issue includes a variety of feature articles, class notes, a calendar of events, and more.

A 12-Year Prospective Study Of The Long-Term Effects Of Early Child Physical Maltreatment On Psychological, Behavioral, And Academic Problems In Adolescence, Jennifer E Lansford, Kenneth A Dodge, Gregory S Pettit, John E Bates, Joseph Crozier, Julie Kaplow

Faculty, Staff and Students Publications

OBJECTIVE: To determine whether child physical maltreatment early in life has long-term effects on psychological, behavioral, and academic problems independent of other characteristics associated with maltreatment.

DESIGN: Prospective longitudinal study with data collected annually from 1987 through 1999.

SETTING AND PARTICIPANTS: Randomly selected, community-based samples of 585 children from the ongoing Child Development Project were recruited the summer before children entered kindergarten in 3 geographic sites. Seventy-nine percent continued to participate in grade 11. The initial in-home interviews revealed that 69 children (11.8%) had experienced physical maltreatment prior to kindergarten matriculation.

MAIN OUTCOME MEASURES: Adolescent assessment of school grades, standardized …

Challenges, Strategies, And Tools For Research Scientists: Using Web-Based Information Resources, Danielle Bodrero Hoggan

E-JASL: Electronic Journal of Academic and Special Librarianship (1999-2009, Volumes 1-10)

Scientists face many challenges in harnessing web-based resources. Information overload, misinformation, fees, poorly designed navigation, and loss of browsability all hamper the scientist searcher. In addition, many scientists rely on only one or two databases and often miss unique information that is available through other sources. Librarians can team up with scientists to develop strategies to overcome the challenges of web-based information. For example, a librarian can teach effective information seeking techniques, including how to use controlled vocabularies, how to evaluate information on the web, and how to complement web-based resources with print resources. Librarians can also help scientists to …

The Personality Profile Of September 11 Hijack Ringleader Mohamed Atta, Aubrey Immelman

Psychology Faculty Publications

This paper presents the results of a posthumous, indirect assessment of the personality of Mohamed Atta, apparent ringleader in the September 11, 2001 terror attack on the World Trade Center and the Pentagon, from the conceptual perspective of Theodore Millon.

Information concerning Mohamed Atta was collected from media reports in the one-month period following the attack and synthesized into a personality profile using the second edition of the Millon Inventory of Diagnostic Criteria (MIDC), which yields 34 normal and maladaptive personality classifications congruent with Axis II of DSM-IV.

The personality profile yielded by the MIDC was analyzed on the …

The Role Of Psychologists In Primary Care: An Integrative Curriculum, Gary Charles Hawley

Loma Linda University Electronic Theses, Dissertations & Projects

Psychologists have been service providers in the health care sector for many years. They are consistently recognized as valued members of health care teams but are not frequently included as primary care providers. Integrated primary care services that include psychologists are a positive step toward achieving a comprehensive model of patient care. The biopsychosocial model is suggested to supplant the current biomedical model for health and wellness conceptualization. Psychologists are trained in the dynamic interplay between biological, psychological, and social domains. However, education at the graduate level for psychologists working specifically in primary care has not been well conceptualized, developed …

Modular Machine Learning Methods For Computer-Aided Diagnosis Of Breast Cancer, Mia Kathleen Markey '94

Doctoral Dissertations

The purpose of this study was to improve breast cancer diagnosis by reducing the number of benign biopsies performed. To this end, we investigated modular and ensemble systems of machine learning methods for computer-aided diagnosis (CAD) of breast cancer. A modular system partitions the input space into smaller domains, each of which is handled by a local model. An ensemble system uses multiple models for the same cases and combines the models' predictions.

Five supervised machine learning techniques (LDA, SVM, BP-ANN, CBR, CART) were trained to predict the biopsy outcome from mammographic findings (BIRADS™) and patient age based on a …

The Impact Of Systematically Varying The Duration Of Breath Samples During Infrared-Based Alcohol Breath Testing, Chris C. Clatterbuck

Dissertations

The present study set out to investigate the reliability and performance of the BAC DataMaster®, an infrared-based alcohol breath testing instrument. The focus of this study was to determine: (a) the impact of varying breath sample duration during testing, (b) if Blood Alcohol Concentration (BAC) levels produced by the DataMaster® (BAC_DM) are significantly different from BAC levels produced by analysis of whole blood (BAC_WB), and (c) if the relationship between BAC_DM estimates and BAC_WB is influenced by the amount of alcohol an examinee has ingested. Each of 27 participants was randomly assigned to one …

What Do We Assess When We Assess A Big 5 Trait? : A Content Analysis Of The Affective, Behavioral, And Cognitive Processes Represented In Big 5 Personality Inventories, Lisa M. Pytlik Zillig, Scott H. Hemenover, Richard A. Dienstbier

Department of Psychology: Faculty Publications

What are personality traits? Are all “broad” traits equally broad in the constructs they encompass and in the pervasiveness of their effects? Or are some traits more or less affective, behavioral, or cognitive in nature? The present study examined these issues as they applied to the Big 5 traits of Neuroticism, Extraversion, Openness, Agreeableness, and Conscientiousness. Expert and novice raters judged the extent to which items from four popular Big 5 inventories contain behavioral, cognitive, or affective components. Traits and inventories were then compared in terms of their relative assessment of these components. Results indicate convergence among inventories but remarkable …

Effect Of Added Mass On Human Unipedal Hopping, Gary P. Austin, Gladys E. Garrett, David Tiberio

All PTHMS Faculty Publications

Although hopping is considered a children's activity, it can be used to provide insight into the neuromuscular and biomechanical performance of adults. This study investigated whether mass added during unipedal hopping altered the vertical stiffness, hopping period, and angular kinematics of the lower exteremity of adults. Measures of two-dimensional kinematics and vertical force were made from 10 healthy men during hopping at a preferred period under three conditions: Body Mass, Body Mass +10%, and Body Mass +20%. Adding mass significantly increased hopping period and hip flexion without significantly affecting vertical stiffness, ankle dorsiflexion, or knee flexion. Overall, the findings agreed …

Effect Of Frequency On Human Unipedal Hopping, Gary P. Austin, David Tiberio, Gladys E. Garrett

All PTHMS Faculty Publications

All mature forms of locomotion involve periods of unilateral stance. Unipedal hopping may provide useful information about the neuromuscular and biomechanical capabilities of a single lower extremity in adults. This study investigated whether hopping influenced vertical stiffness and lower extremity angular kinematics during human unipedal hopping. Vertical force and two-dimensional kinematics were measured in 10 healthy males hopping at three frequencies: preferred, +20%, and -20%. At +20%, compared to preferred, vertical stiffness increased 55% as hip flexion, knee flexion, and ankle dorsiflexion decreased, while at -20%, vertical stiffness decreased 39.4% as hip flexion, knee flexion, and ankle dorsiflexion increased. As …

Development Of Dose Coefficients For Radionuclides Produced In Spallation Neutron Sources, Phillip W. Patton

Transmutation Sciences Physics (TRP)

A research consortium comprised of representatives from several universities and national laboratories has been established as part of this on-going project to generate internal and external dose conversion coefficients for radionuclides produced in spallation neutron sources. Information obtained from this multi-year study will be used to support the siting and licensing of future accelerator-driven nuclear initiatives within the U.S. Department of Energy complex, including the Spallation Neutron Source (SNS) and Accelerator Production of Tritium (APT) Projects. Determination of these coefficients will also fill data gaps for several hundred radionuclides that exist in Federal Guide Report No. 11 and in Publications …

Residential Radon Exposure And Lung Cancer: Variation In Risk Estimates Using Alternative Exposure Scenarios, R. William Field, Brian J. Smith, Daniel J. Steck, Charles F. Lynch

Physics Faculty Publications

The most direct way to derive risk estimates for residential radon progeny exposure is through epidemiologic studies that examine the association between residential radon exposure and lung cancer. However, the National Research Council concluded that the inconsistency among prior residential radon case-control studies was largely a consequence of errors in radon dosimetry. This paper examines the impact of applying various epidemiologic dosimetry models for radon exposure assessment using a common data set from the Iowa Radon Lung Cancer Study (IRLCS). The IRLCS uniquely combined enhanced dosimetric techniques, individual mobility assessment, and expert histologic review to examine the relationship between cumulative …