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2009

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Articles 1 - 30 of 7101

Full-Text Articles in Physical Sciences and Mathematics

Analyzing Direct Effects In Randomized Trials With Secondary Interventions: An Application To Hiv Prevention Trials, Michael Rosenblum, Nicholas Jewell, Mark Van Der Laan, Steven Shiboski, Ariane Van Der Straten, Nancy Padian Dec 2015

Analyzing Direct Effects In Randomized Trials With Secondary Interventions: An Application To Hiv Prevention Trials, Michael Rosenblum, Nicholas Jewell, Mark Van Der Laan, Steven Shiboski, Ariane Van Der Straten, Nancy Padian

Michael Rosenblum MD

The `Methods for improving reproductive health in Africa' trial is a recently completed randomized trial that investigated the effect of diaphragm and lubricant gel use in reducing infection by the human immunodeficiency virus (HIV) among susceptible women. 5045 women were randomly assigned to either the active treatment arm or not. Additionally, all subjects in both arms received intensive condom counselling and provision, the `gold standard' HIV prevention barrier method. There was much lower reported use of condoms in the intervention arm than in the control arm, making it difficult to answer important public health questions based solely on the intention-to-treat ...


The Risk Of Virologic Failure Decreases With Duration Of Hiv Suppression, At Greater Than 50% Adherence To Antiretroviral Therapy., Michael Rosenblum, Steven Deeks, Mark Van Der Laan, David Bangsberg Dec 2015

The Risk Of Virologic Failure Decreases With Duration Of Hiv Suppression, At Greater Than 50% Adherence To Antiretroviral Therapy., Michael Rosenblum, Steven Deeks, Mark Van Der Laan, David Bangsberg

Michael Rosenblum MD

Background We hypothesized that the percent adherence to antiretroviral therapy necessary to maintain HIV suppression would decrease with longer duration of viral suppression. Methodology Eligible participants were identified from the REACH cohort of marginally housed HIV infected adults in San Francisco. Adherence to antiretroviral therapy was measured through pill counts obtained at unannounced visits by research staff to each participant's usual place of residence. Marginal structural models and targeted maximum likelihood estimation methodologies were used to determine the effect of adherence to antiretroviral therapy on the probability of virologic failure during early and late viral suppression. Principal Findings A ...


Sources Of Gravity Waves In The Lower Stratosphere Above South Pole, Zhenhua Li, Walter Robinson, Alan Liu Aug 2013

Sources Of Gravity Waves In The Lower Stratosphere Above South Pole, Zhenhua Li, Walter Robinson, Alan Liu

Zhenhua Li

No abstract provided.


Factors Influencing The Persistence Of Fecal Bacteroides In Stream Water, Alyssa Bell, Alice Layton, Larry Mckay, Dan Williams, Randy Gentry, Gary Sayler Jun 2013

Factors Influencing The Persistence Of Fecal Bacteroides In Stream Water, Alyssa Bell, Alice Layton, Larry Mckay, Dan Williams, Randy Gentry, Gary Sayler

Gary S. Sayler

Laboratory microcosm experiments were used to assess the effects of environmental parameters on the persistence of the Bacteroides 16S rRNA genes derived from equine fecal samples in stream water to investigate the utility of Bacteroides spp. as fecal indicator organisms. Quantitative real-time polymerase chain reaction (qPCR) was used to measure gene concentrations over time with treatments designed to compare filtered vs. unfiltered stream water, fecal aggregate size, initial fecal concentrations, and water temperatures. Comparison of Bacteroides16S rRNA genes/mL in microcosms constructed with unfiltered stream water and filtered stream water indicated that stream water filtration to remove indigenous microorganisms followed ...


Improved Synthesis Of Pincer Ligand Precursor, And Synthesis And Structural Characterization Of Terphenyl Scaffolded S–C–S Palladium Pincer Complex., Paul Schroder, Thomas Spilker, Wilson Luu, James Updegraff, Man Lung Kwan, Paul Challen, John Protasiewicz May 2013

Improved Synthesis Of Pincer Ligand Precursor, And Synthesis And Structural Characterization Of Terphenyl Scaffolded S–C–S Palladium Pincer Complex., Paul Schroder, Thomas Spilker, Wilson Luu, James Updegraff, Man Lung Kwan, Paul Challen, John Protasiewicz

Man Lung Desmond Kwan

An easier and more expedient synthesis of 2,6-(BrCH2C6H4)2-4-I-C6H3 (2) is reported. This material allowed easy synthesis of the new pincer ligand precursor 2,6-(4-CH3C6H4SCH2C6H4)2-4-I-C6H3 (3) in 87% yield. Compound 3 reacts with Pd2(dba)3 to give the new palladium pincer complex 4. Compound 4 has been fully characterized, including structural characterization by single crystal X-ray diffraction methods. The results of the crystallographic work on 4 reveal a twisted type pincer complex not unlike related terphenyl pincer complexes.


The European Court Of Human Rights Ruling Against Britain's Policy Of Keeping Fingerprints & Dna Samples Of Criminal Suspects, K. Michael, Clive Harfield Feb 2013

The European Court Of Human Rights Ruling Against Britain's Policy Of Keeping Fingerprints & Dna Samples Of Criminal Suspects, K. Michael, Clive Harfield

Clive Harfield

In England and Wales, the Police and Criminal Evidence Act 1984 (the PACE) contained powers for the taking of fingerprints, and samples in the form of deoxyribonucleic acid (DNA). In 2001, Section 64(1A) of the PACE was substituted with Section 82 of the Criminal Justice and Police Act. The change to legislation meant that a suspect of a crime would have their fingerprints and samples permanently stored on the police national computer (PNC) even after having been acquitted. This paper critically analyses the circumstances of the landmark case of S. AND MARPER V. THE UNITED KINGDOM in two different ...


Parts Of The Whole: Observing The State Of The System, Dorothy Wallace Dec 2009

Parts Of The Whole: Observing The State Of The System, Dorothy Wallace

Numeracy

This column draws on the approach of statistician J. Edwards Deming to analyze sources and consequences of variation in an education system. Educational systems are not immune from the effects of poor statistical control, which makes it difficult for teachers to teach effectively and for managers such as principals to improve on school performance. It is also argued that the need for statistical control in these areas is in tension, if not outright conflict, with our goals for educating students.


Two Popular Books For Quantitative Literacy: What The Numbers Say, And The Numbers Game, Robert G. Root Dec 2009

Two Popular Books For Quantitative Literacy: What The Numbers Say, And The Numbers Game, Robert G. Root

Numeracy

Niederman, Derrick, and Boyum, David. What the Numbers Say: A Field Guide to Mastering Our Numerical World. (New York: Broadway Books/Random House, 2003). 288 pp. Hardcover, ISBN 978-0-7679-0998-3. Paperback, 978-0-7679-0999-0. Available as an eBook.

Blastland, Michael, and Dilnot, Andrew. The Numbers Game: The Commonsense Guide to Understanding Numbers in the News, in Politics and in Life. (New York: Gotham Books/Penguin, 2009). 192 pp. Hardcover, ISBN 978-1-5924-0423-0. Paperback, ISBN 978-1-5924-0485-8. Available as an eBook.

Popular books on quantitative literacy need to be easy to read, reasonably comprehensive in scope, and include examples that are thought-provoking and memorable. In contrast ...


Numeracy: Open-Access Publishing To Reduce The Cost Of Scholarly Journals, Todd A. Chavez Dec 2009

Numeracy: Open-Access Publishing To Reduce The Cost Of Scholarly Journals, Todd A. Chavez

Numeracy

Each fiscal year, as academic librarians throughout the United States prepare materials budgets, a national “groan” ensues. Regardless of their format (i.e. print or digital), serial subscription costs are escalating, in the process impacting the role of the library in advancing scholarly communication . This paper examines some of the economic issues concerning open-access (OA) journal publishing. The importance of quantitative literacy is suggested for librarians and academics seeking a better understanding of alternatives to traditional journal subscription models and to anyone considering ventures into OA publishing. Quantitative literacy is essential for managing alternatives to the rising cost of scholarly ...


College Algebra In Context: A Project Incorporating Social Issues, Michael T. Catalano Dec 2009

College Algebra In Context: A Project Incorporating Social Issues, Michael T. Catalano

Numeracy

This paper discusses the development of an innovative college algebra text designed for use in a data-driven, activity-oriented college algebra course, incorporating realistic problem situations emphasizing social and economic issues, including hunger and poverty, energy, and the environment. The course incorporates quantitative literacy themes, is informed by existing college algebra texts within the college algebra reform movement, and implements a collaborative pedagogical approach intended to provide future K-12 teachers an alternative model for the teaching of mathematics. The paper contains a short history of the project development phase, supported by an NSF grant (DUE #0442979), as well as the perceived ...


An Activity Promoting The Practice Of Quantitative Literacy For Pre– And In–Service Teachers Of Mathematics And Science, Timothy L. Sorey, Teri Willard, Duane Sholz Dec 2009

An Activity Promoting The Practice Of Quantitative Literacy For Pre– And In–Service Teachers Of Mathematics And Science, Timothy L. Sorey, Teri Willard, Duane Sholz

Numeracy

The purpose of this article is to describe a hands-on, laboratory activity that provided pre-service teachers in mathematics and science methods courses, and also some in-service mathematics teachers, with the opportunity to exercise quantitative literacy (QL) skills. The focus of the activity is electrical resistance, more particularly the resistance (in ohms) that is painted on small resistors by the use of color-coded bands, one of which is a band for % error. The activity consists of four parts. In the first, student teams familiarize themselves with the code, measure the ohmage of resistors for which the codes are visible, and compare ...


Are Statistics Labs Worth The Effort?--Comparison Of Introductory Statistics Courses Using Different Teaching Methods, Jose H. Guardiola, Nadina Duran-Hutchings, Hassan Elsalloukh Dec 2009

Are Statistics Labs Worth The Effort?--Comparison Of Introductory Statistics Courses Using Different Teaching Methods, Jose H. Guardiola, Nadina Duran-Hutchings, Hassan Elsalloukh

Numeracy

This paper compares the academic performance of students in three similar elementary statistics courses taught by the same instructor, but with the lab component differing among the three. One course is traditionally taught without a lab component; the second with a lab component using scenarios and an extensive use of technology, but without explicit coordination between lab and lecture; and the third using a lab component with an extensive use of technology that carefully coordinates the lab with the lecture. Extensive use of technology means, in this context, using Minitab software in the lab section, doing homework and quizzes using ...


Envisioning A Quantitative Studies Center: A Liberal Arts Perspective, Gizem Karaali, Philip I. Choi, Sara Owsley Sood, Eric B. Grosfils Dec 2009

Envisioning A Quantitative Studies Center: A Liberal Arts Perspective, Gizem Karaali, Philip I. Choi, Sara Owsley Sood, Eric B. Grosfils

Numeracy

Several academic institutions are searching for ways to help students develop their quantitative reasoning abilities and become more adept at higher-level tasks that involve quantitative skills. In this note we study the particular way Pomona College has framed this issue within its own context and what it plans to do about it. To this end we describe our efforts as members of a campus-wide committee that was assigned the duty of investigating the feasibility of founding a quantitative studies center on our campus. These efforts involved analysis of data collected through a faculty questionnaire, discipline-specific input obtained from each departmental ...


A Rubric For Assessing Quantitative Reasoning In Written Arguments, Nathan D. Grawe, Neil S. Lutsky, Christopher J. Tassava Dec 2009

A Rubric For Assessing Quantitative Reasoning In Written Arguments, Nathan D. Grawe, Neil S. Lutsky, Christopher J. Tassava

Numeracy

This paper introduces a rubric for assessing QR in student papers and analyzes the inter-rater reliability of the instrument based on a reading session involving 11 participants. Despite the disciplinary diversity of the group (which included a faculty member from the arts and literature, two staff members, and representatives from five natural and social science departments), the rubric produced reliable measures of QR use and proficiency in a sample of student papers. Readers agreed on the relevance and extent of QR in 75.0 and 81.9 percent of cases respectively (corresponding to Cohen’s κ= 0.611 and 0 ...


Confessions Of A Weak Tie, Joel Best Dec 2009

Confessions Of A Weak Tie, Joel Best

Numeracy

No abstract provided.


Five Thousand Downloads, H L Vacher Dec 2009

Five Thousand Downloads, H L Vacher

Numeracy

No abstract provided.


Anti-Cloaking: The Mathematics Of Disguise, Theresa C. Anderson, Brooke E. Phillips Dec 2009

Anti-Cloaking: The Mathematics Of Disguise, Theresa C. Anderson, Brooke E. Phillips

Mathematical Sciences Technical Reports (MSTR)

Recent developments in cloaking, the ability to selectively bend electromagnetic waves so as to render an object invisible, have been abundant. Based on cloaking principles, we will describe several ways to mathematically disguise objects in the context of electrical impedance imaging. Through the use of a change-of-variables scheme we show how one can make an object appear enlarged, translated, or rotated by surrounding it with a suitable "metamaterial," a man-made material that selectively redirects current. Analysis of eigenvectors and eigenvalues, which describe how current flows, follow. We prove that in order to disguise an object, a metamaterial must encompass both ...


Electrical Impedance Imaging Of Corrosion On A Partially Accessible 2-Dimensional Region, Court Hoang, Katherine Osenbach Dec 2009

Electrical Impedance Imaging Of Corrosion On A Partially Accessible 2-Dimensional Region, Court Hoang, Katherine Osenbach

Mathematical Sciences Technical Reports (MSTR)

In this paper we examine the inverse problem of determining the amount of corrosion on an inaccessible surface of a two-dimensional region. Using numerical methods, we develop an algorithm for approximating corrosion profile using measurements of electrical potential along the accessible portion of the region. We also evaluate the effect of error on the problem, address the issue of ill-posedness, and develop a method of regularization to correct for this error. An examination of solution uniqueness is also presented.


Job Seeking And Job Application In Social Networking Sites : Predicting Job Seekers' Behavioral Intentions, Maria Marcella Plummer Dec 2009

Job Seeking And Job Application In Social Networking Sites : Predicting Job Seekers' Behavioral Intentions, Maria Marcella Plummer

Dissertations

Social networking sites (SNSs) are revolutionizing the way in which employers and job seekers connect and interact with each other. Despite the reported benefits of SNSs with respect to finding a job, there are issues such as privacy concerns that might be deterring job seekers from using these sites in their attempts to secure a job. It is therefore important to understand the factors that are salient in predicting job seekers' use of SNSs in applying for jobs.

In this research, a theoretical model was developed to explicate job seekers' intentions to use SNSs to apply for jobs. Two aspects ...


Understanding Cognitive Differences In Processing Competing Visualizations Of Complex Systems, Madhavi Mukul Chakrabarty Dec 2009

Understanding Cognitive Differences In Processing Competing Visualizations Of Complex Systems, Madhavi Mukul Chakrabarty

Dissertations

Node-link diagrams are used represent systems having different elements and relationships among the elements. Representing the systems using visualizations like node-link diagrams provides cognitive aid to individuals in understanding the system and effectively managing these systems. Using appropriate visual tools aids in task completion by reducing the cognitive load of individuals in understanding the problems and solving them. However, the visualizations that are currently developed lack any cognitive processing based evaluation. Most of the evaluations (if any) are based on the result of tasks performed using these visualizations. Therefore, the evaluations do not provide any perspective from the point of ...


Perturbed Spherical Objects In Acoustic And Fluid Flow Fields, Manmeet Kaur Dec 2009

Perturbed Spherical Objects In Acoustic And Fluid Flow Fields, Manmeet Kaur

Dissertations

In this study, the time averaged acoustic radiation force and drag on a small, nearly spherical object suspended freely in a stationary sound wave field in a compressible, low viscosity fluid is to be calculated. This problem has been solved for a spherical object, and it has many important engineering applications related to segregation and separation processes for particles in fluids such as water. Small but significant errors have occurred in the predicted behavior of the particles using the existing approximate solutions based on perfect spheres. The classical approach has been extended in this research to objects that deviate slightly ...


Integration Of Electronic And Optical Techniques In The Design And Fabrication Of Pressure Sensors, Ivan Padron Dec 2009

Integration Of Electronic And Optical Techniques In The Design And Fabrication Of Pressure Sensors, Ivan Padron

Dissertations

Since the introduction of micro-electro-mechanical systems fabrication methods, piezoresistive pressure sensors have become the more popular pressure transducers. They dominate pressure sensor commercialization due to their high performance, stability and repeatability. However, increasing demand for harsh environment sensing devices has made sensors based on Fabry-Perot interferometry the more promising optical pressure sensors due to their high degree of sensitivity, small size, high temperature performance, versatility, and improved immunity to environmental noise and interference. The work presented in this dissertation comprises the design, fabrication, and testing of sensors that fuse these two pressure sensing technologies into one integrated unit. A key ...


Modeling And Quasi-Monte Carlo Simulation Of Risk In Credit Portfolios, Bo Ren Dec 2009

Modeling And Quasi-Monte Carlo Simulation Of Risk In Credit Portfolios, Bo Ren

Dissertations

Credit risk is the risk of losing contractually obligated cash flows promised by a counterparty such as a corporation, financial institution, or government due to default on its debt obligations. The need for accurate pricing and hedging of complex credit derivatives and for active management of large credit portfolios calls for an accurate assessment of the risk inherent in the underlying credit portfolios. An important challenge for modeling a credit portfolio is to capture the correlations within the credit portfolio. For very large and homogeneous portfolios, analytic and semi-analytic approaches can be used to derive limiting distributions. However, for portfolios ...


Semantics And Efficient Evaluation Of Partial Tree-Pattern Queries On Xml, Xiaoying Wu Dec 2009

Semantics And Efficient Evaluation Of Partial Tree-Pattern Queries On Xml, Xiaoying Wu

Dissertations

Current applications export and exchange XML data on the web. Usually, XML data are queried using keyword queries or using the standard structured query language XQuery the core of which consists of the navigational query language XPath. In this context, one major challenge is the querying of the data when the structure of the data sources is complex or not fully known to the user. Another challenge is the integration of multiple data sources that export data with structural differences and irregularities. In this dissertation, a query language for XML called Partial Tree-Pattern Query (PTPQ) language is considered. PTPQs generalize ...


Institutional Controls And Brownfield Redevelopment, Ronnachai Tiyarattanachai Dec 2009

Institutional Controls And Brownfield Redevelopment, Ronnachai Tiyarattanachai

Dissertations

Institutional controls (ICs) are used to reduce risks to human health and environment from exposure to contaminants at Brownfield sites. Regulators approve use of ICs in Brownfield redevelopment with the expectation that ICs will remain effective over the long-term under proper oversight mechanisms. However, a recent review of compliance statuses of Brownfield sites with ICs implemented in Massachusetts and New Jersey indicated a significant percentage of the sites are out of compliance status.

Implementation of ICs depends on compliance efforts by humans. Thus, consistency of implementation over the long-term is questionable because there are several potential problems due to human ...


Masthead Dec 2009

Masthead

Journal of Digital Forensics, Security and Law

No abstract provided.


Relationship Between Photospheric Magnetic Fields And Coronal Activities, Changyi Tan Dec 2009

Relationship Between Photospheric Magnetic Fields And Coronal Activities, Changyi Tan

Dissertations

Coronal emission comes in two forms, a steady component where the corona is heated to million degrees and a much hotter transient component of solar flares. Both components are known to be related to the evolution of surface magnetic fields. This dissertation studies the evolution of photospheric magnetic fields and flow fields and their relation to the properties of these two coronal emission components.

The key issue in the study of the steady coronal emission is the coronal heating problem: how the corona is heated to millions of degrees while the underlying solar photosphere is only a few thousand degrees ...


Algorithms In Comparative Genomics, Satish Chikkagoudar Dec 2009

Algorithms In Comparative Genomics, Satish Chikkagoudar

Dissertations

The field of comparative genomics is abundant with problems of interest to computer scientists. In this thesis, the author presents solutions to three contemporary problems: obtaining better alignments for phylogeny reconstruction, identifying related RNA sequences in genomes, and ranking Single Nucleotide Polymorphisms (SNPs) in genome-wide association studies (GWAS).

Sequence alignment is a basic and widely used task in bioinformatics. Its applications include identifying protein structure, RNAs and transcription factor binding sites in genomes, and phylogeny reconstruction. Phylogenetic descriptions depend not only on the employed reconstruction technique, but also on the underlying sequence alignment. The author has studied and established a ...


Virtual World Commerce Adoption (Vwca) : A Case Study Of Second Life Investigating The Impacts Of Perceived Affordances, Trust, And Need Satisfaction, Kamolbhan Olapiriyakul Dec 2009

Virtual World Commerce Adoption (Vwca) : A Case Study Of Second Life Investigating The Impacts Of Perceived Affordances, Trust, And Need Satisfaction, Kamolbhan Olapiriyakul

Dissertations

Virtual worlds are computer-simulated worlds in which multi-players can simultaneously interact in a rich graphical environment. The development of virtual worlds, along with the massive growth of users, creates opportunities for business organizations. This dissertation involves many studies regarding virtual world adoption in business by virtual consumers.

Most of the research in Information Systems (IS) was conducted investigating factors influencing technology adoption, such as ease of use and usefulness, subjective norms and behavioral controls, self-efficacy, performance and effort expectancy, flow, etc. However, most of these research studies focused neither on design aspects related to affordances nor users' goal-oriented behaviors, such ...


Detection Of Psilocybin Mushroom Analogs In Chocolate: Incorporating Current Events Into The Undergraduate Teaching Laboratory, Brandon Huskins, Christopher Dockery Dec 2009

Detection Of Psilocybin Mushroom Analogs In Chocolate: Incorporating Current Events Into The Undergraduate Teaching Laboratory, Brandon Huskins, Christopher Dockery

Faculty Publications

In this experiment, tryptamine is used as a psilocin analog and is dispersed onto a Fisher brand cellulose laboratory sponge to simulate dehydrated mushrooms. The resulting “mushroom” material is ground, molded into chocolate, and presented to student groups for real-world and applied analyses. Students isolate the tryptamine from the chocolate using their knowledge of drug chemistry, solubility, pH, extractions, etc. Qualitative analysis is conducted by comparison to standards (Thin Layer Chromatography or Gas Chromatography) and quantitative analysis is conducted by Gas Chromatography using the method of internal standards.