Medicine and Health Sciences Commons^™

Detectability Of Excitatory Versus Inhibitory Drive In An Integrate-And-Fire-Or-Burst Thalamocortical Relay Neuron Model, Gregory D. Smith, S. M. Sherman

Arts & Sciences Articles

Although inhibitory inputs are often viewed as equal but opposite to excitatory inputs, excitatory inputs may alter the firing of postsynaptic cells more effectively than inhibitory inputs. This is because spike cancellation produced by an inhibitory input requires coincidence in time, whereas an excitatory input can add spikes with less temporal constraint. To test for such potential differences, especially in the context of the function of thalamocortical (TC) relay nuclei, we used a stochastic “integrate-and-fire-or-burst” TC neuron model to quantify the detectability of excitatory and inhibitory drive in the presence and absence of the low-threshold Ca 2+ current, IT, and …

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 …

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 …

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

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 …

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 …

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 …

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

E-JASL 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 …

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 …

Comparative Genomic Hybridization Array Analysis, Annette M. Molinaro, Mark J. Van Der Laan, Dan H. Moore

U.C. Berkeley Division of Biostatistics Working Paper Series

At the present time, there is increasing evidence that cancer may be regulated by the number of copies of genes in tumor cells. Through microarray technology it is now possible to measure the number of copies of thousands of genes and gene segments in samples of chromosomal DNA. Microarray comparative genomic hybridization (array CGH) provides the opportunity to both measure DNA sequence copy number gains and losses and map these aberrations to the genomic sequence. Gains can signify the over-expression of oncogenes, genes which stimulate cell growth and have become hyperactive, while losses can signify under-expression of tumor suppressor genes, …

Inside Unlv, Diane Russell, Betty Blodgett, Kevin Force, Jennifer Vaughan, Cate Weeks, Jonathan Paver

Inside UNLV

No abstract provided.

Using Small Group Assignments In Teaching Research Ethics, Kenneth D. Pimple

Ethics in Science and Engineering National Clearinghouse

No abstract provided.

Using Short Writing Assignments In Teaching Research Ethics, Kenneth D. Pimple

Ethics in Science and Engineering National Clearinghouse

Regularly asking students to write down their thoughts and reactions to class readings and discussions is an effective method of teaching and assessing student learning. Furthermore, as composition teachers will attest, frequent writing assignments, regardless of content, dramatically improve writing skills. Asking students to think “on paper” about topics encountered in the classroom encourages them to think about those topics in greater depth, relate them to their own lives, and thus connect the classroom to the world outside. I will describe four kinds of useful short writing assignments – freewriting, the non-quiz, the one-minute paper, and logbooks.

Middlefield Open Space And Recreation Project, Center For Economic Development

Center for Economic Development Technical Reports

Over one thousand acres of farmland, open space, and wetlands are converted to residential or commercial development each week in New England. In Massachusetts, nearly two acres of open space land is lost to development every hour. Current development trends suggest that this building pattern, referred to as sprawl, is likely to continue into the near future. Because the negative consequences of sprawl development are highly visible, residents of Massachusetts are becoming increasingly concerned about its impact on their communities. Residents see the unique character of their communities being transformed by uncontrolled residential and commercial development. Green fields and open …

Estimating Causal Parameters In Marginal Structural Models With Unmeasured Confounders Using Instrumental Variables, Tanya A. Henneman, Mark Johannes Van Der Laan, Alan E. Hubbard

U.C. Berkeley Division of Biostatistics Working Paper Series

For statisticians analyzing medical data, a significant problem in determining the causal effect of a treatment on a particular outcome of interest, is how to control for unmeasured confounders. Techniques using instrumental variables (IV) have been developed to estimate causal parameters in the presence of unmeasured confounders. In this paper we apply IV methods to both linear and non-linear marginal structural models. We study a specific class of generalized estimating equations that is appropriate to these data, and compare the performance of the resulting estimator to the standard IV method, a two-stage least squares procedure. Our results are applied to …

Development Of Dose Coefficients For Radionulides Produced In Spallation Neutron Sources: Annual Report, Phillip W. Patton, Mark Rudin

Transmutation Sciences Physics (TRP)

The University of Nevada, Las Vegas (UNLV) Transmutation Research Program has been tasked to support U.S. Department of Energy (DOE) efforts to assess the health risks associated with the operation of each of their accelerator-driven nuclear facilities for both NEPA and PSAR development. Quantifying the radiological risks to workers will have to be addressed during the design and siting of each of these facilities. U.S. Environmental Protection Agency (EPA) Federal Guidance Report No. 11 “Limiting Values of Intake and Air Concentration and Dose Conversion Factors for Inhalation, Submersion, and Ingestion”, developed two derived guides, Annual Limit on Intake (ALI) and …

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

Transmutation Sciences Physics (TRP)

For the first year of this effort, the UNLV research team set out four objectives. First, the university and laboratory consortium had to be established. This consortium was tasked with helping to determine the methodology for determining the dose coefficients, and to ensure that the resulting DCs will be of use to the national programs developing accelerator-driven nuclear systems (such as the SNS or an accelerator-driven transmutation system) and to the health physics community as a whole. The second goal of this program was to determine a methodology and then prioritize the radionuclides so that the research effort would address …

Assessing Student Learning In The Responsible Conduct Of Research, Kenneth D. Pimple

Ethics in Science and Engineering National Clearinghouse

Introduction

As with all effective teaching, a key element in any unit designed to teach research ethics is assessment of student learning, whether the “unit” is a whole course, a brown bag lunch seminar, or a few sessions or segments of sections within a course. How can we know what our students learned, and whether they learned what we intended them to learn? How can we tell whether our instructional goals were met?

I am reminded of the Saturday Night Live skit in which a reporter asks President Carter, “Why are you building the B-1 Bomber?” To which Carter replies, …

Medtextus: An Ontology-Enhanced Medical Portal, Gondy Leroy, Hsinchun Chen

CGU Faculty Publications and Research

In this paper we describe MedTextus, an online medical search portal with dynamic search and browse tools. To search for information, MedTextus lets users request synonyms and related terms specifically tailored to their query. A mapping algorithm dynamically builds the query context based on the UMLS ontology and then selects thesaurus terms that fit this context. Users can add these terms to their query and meta-search five medical databases. To facilitate browsing, the search results can be reviewed as a list of documents per database, as a set of folders into which all the documents are automatically categorized based on …

Filling Preposition-Based Templates To Capture Information From Medical Abstracts, Gondy Leroy, Hsinchun Chen

CGU Faculty Publications and Research

Due to the recent explosion of information in the biomedical field, it is hard for a single researcher to review the complex network involving genes, proteins, and interactions. We are currently building GeneScene, a toolkit that will assist researchers in reviewing existing literature, and report on the first phase in our development effort: extracting the relevant information from medical abstracts. We are developing a medical parser that extracts information, fills basic prepositional-based templates, and combines the templates to capture the underlying sentence logic. We tested our parser on 50 unseen abstracts and found that it extracted 246 templates with a …

Actiononaias Ligamentina As A Biomonitor In The Green River: An Unique Approach For Analysis Of Environmental Impacts, Robert Kirkland

Masters Theses & Specialist Projects

Biomonitoring has become an important component in bioassessment programs. It is used to maintain high water quality standards, and determine contaminant levels and biological affects in areas that have been heavily disturbed. The objectives of this research were 1) to improve and apply certain modern biomonitoring techniques and 2) to locate possible contaminant sources affecting the flora and fauna of the Green River and of Mammoth Cave. Actinonaias ligamentina (Lamarck, 1819), a freshwater mussel, was used for interpretation of these impacts as well as refinement of biomonitoring techniques. The mussels were collected in the Lawler Bend region of the Green …