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2009

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Articles 7591 - 7616 of 7616

Full-Text Articles in Physical Sciences and Mathematics

Should Biomarker Estimates Of Hiv Incidence Be Adjusted?, Ron Brookmeyer Dec 2008

Should Biomarker Estimates Of Hiv Incidence Be Adjusted?, Ron Brookmeyer

Ron Brookmeyer

Objective: To evaluate adjustment procedures that have been proposed to correct HIV incidence rates derived from cross-sectional surveys of biomarkers (BED). These procedures were motivated by some reports that the biomarker BED approach overestimates incidence when compared to cohort studies.

Design: Considered the Hargrove and McDougal adjustment procedures that adjust biomarker estimates of HIV incidence rates for misclassification with respect to the timing of infections.

Methods: Performed mathematical and statistical analysis of the adjustment formulas. Evaluated sources of error in cohort studies of incidence that could also explain discrepancies between cohort and biomarker estimates.

Results: The McDougal adjustment has no …


The Effects Of Herd Immunity On The Power Of Vaccine Trials, Blake Charvat, Ron Brookmeyer, Jay Herson Dec 2008

The Effects Of Herd Immunity On The Power Of Vaccine Trials, Blake Charvat, Ron Brookmeyer, Jay Herson

Ron Brookmeyer

We evaluate the effects of herd immunity on the power of vaccine trials. We consider large-scale trials in which persons are individually randomized to either placebo or vaccine. We evaluate the adequacy of naive power calculations that ignore the effects of herd immunity such as those based on the comparison of two independent binomials. We developed a simulation design to evaluate the quantitative effects of herd immunity on power. The simulation design accounted for nonhomogeneous mixing. We found that naive power calculations that ignore the effects of herd immunity can seriously overestimate power. In fact, we found that as sample …


Towards Self-Configurable Overlay Networks, Philadelphia University Dec 2008

Towards Self-Configurable Overlay Networks, Philadelphia University

Philadelphia University, Jordan

No abstract provided.


My Trig Book, Bruce Kessler Dec 2008

My Trig Book, Bruce Kessler

Bruce Kessler

This is the MATH 117 Trigonometry text developed by Dr. Bruce Kessler for the Gatton Academy of Math and Science at Western Kentucky University for the Academy sections of the course. The text has also been used in two online course offerings. Revised 7/19/11.

Free readers are available for all of the files that accompany the book. Mathematica Player is available at http://www.wolfram.com/products/player/. QuickTime Player is available at http://www.apple.com/quicktime/.


Diamond Theory Collections. A Collection Of Papers And Fragments Towards Diamond Theory 2007-2009, Rudolf Kaehr Dec 2008

Diamond Theory Collections. A Collection Of Papers And Fragments Towards Diamond Theory 2007-2009, Rudolf Kaehr

Rudolf Kaehr

No abstract provided.


Genome-Wide Scan Reveals Association Of Psoriasis With Il-23 And Nf-B Pathways, Rajan P. Nair, Kristina C. Duffin, Cynthia Helms, Jun Ding, Philip E. Stuart, David Goldgar, Johann E. Gudjonsson, Yun Li, Trilokraj Tejasvi, Bing-Jiag Feng, Andreas Ruether, Stefan Schreiber, Michael Weichenthal, Dafna Gladman, Proton Rahman, Steven J. Schrodi, Sampath Prahalad, Stephen L. Guthery, Judith Fischer, Wilson Liao, Pui-Yan Kwok, Alan Menter, G Mark Lathrop, Carol A. Wise, Ann B. Begovich, John J. Voorhees, James T. Elder, Gerald G. Krueger, Anne M. Bowcock, Goncalo R. Abecasis Dec 2008

Genome-Wide Scan Reveals Association Of Psoriasis With Il-23 And Nf-B Pathways, Rajan P. Nair, Kristina C. Duffin, Cynthia Helms, Jun Ding, Philip E. Stuart, David Goldgar, Johann E. Gudjonsson, Yun Li, Trilokraj Tejasvi, Bing-Jiag Feng, Andreas Ruether, Stefan Schreiber, Michael Weichenthal, Dafna Gladman, Proton Rahman, Steven J. Schrodi, Sampath Prahalad, Stephen L. Guthery, Judith Fischer, Wilson Liao, Pui-Yan Kwok, Alan Menter, G Mark Lathrop, Carol A. Wise, Ann B. Begovich, John J. Voorhees, James T. Elder, Gerald G. Krueger, Anne M. Bowcock, Goncalo R. Abecasis

Steven J Schrodi

Psoriasis is a common immune-mediated disorder that affects the skin, nails and joints. To identify psoriasis susceptibility loci, we genotyped 438,670 SNPs in 1,409 psoriasis cases and 1,436 controls of European ancestry. We followed up 21 promising SNPs in 5,048 psoriasis cases and 5,041 controls. Our results provide strong support for the association of at least seven genetic loci and psoriasis (each with combined P < 5 10-8). Loci with confirmed association include HLA-C, three genes involved in IL-23 signaling (IL23A, IL23R, IL12B), two genes that act downstream of TNF- and regulate NF-B signaling (TNIP1, TNFAIP3) and two genes involved in the modulation of Th2 immune responses (IL4, IL13). Although the proteins encoded in these loci are known to interact biologically, we found no evidence for epistasis between associated SNPs. Our results expand the catalog of genetic loci implicated in psoriasis susceptibility and suggest priority targets for study in other auto-immune disorders.


A Fine Mapping Theorem To Refine Results From Association Genetics Studies, Steven J. Schrodi Dec 2008

A Fine Mapping Theorem To Refine Results From Association Genetics Studies, Steven J. Schrodi

Steven J Schrodi

No abstract provided.


Homeland Security: Fostering Public-Private Partnerships, George H. Baker, Cheryl J. Elliott Dec 2008

Homeland Security: Fostering Public-Private Partnerships, George H. Baker, Cheryl J. Elliott

George H Baker

Recent U.S. high consequence events have clarified the importance of government collaboration with industry. The benefit of such collaboration was one of the most important lessons learned from Hurricane Katrina. The resources owned and controlled by American industry dwarf those available to local, state and even the federal government departments. Better agreements and incentives to bring the full capabilities of industry squarely into the national response agenda will be indispensable in effectively responding to large-scale catastrophes. At our 2007 Symposium, General Russel Honoré, who led the National Guard response to Katrina stated, “We need the partnering between local, state, and …


Modeling Forbidden Line Emission Profiles From Colliding Wind Binaries., R. Ignace, R. Bessey, C. S. Price Dec 2008

Modeling Forbidden Line Emission Profiles From Colliding Wind Binaries., R. Ignace, R. Bessey, C. S. Price

Richard Ignace

This paper presents calculations for forbidden emission-line profile shapes arising from colliding wind binaries. The main application is for systems involving a Wolf–Rayet (WR) star and an OB star companion. The WR wind is assumed to dominate the forbidden line emission. The colliding wind interaction is treated as an Archimedean spiral with an inner boundary. Under the assumptions of the model, the major findings are as follows. (i) The redistribution of the WR wind as a result of the wind collision is not flux conservative but typically produces an excess of line emission; however, this excess is modest at around …


Bayesian Statistics, Joseph F. Lucke Dec 2008

Bayesian Statistics, Joseph F. Lucke

Joseph Lucke

No abstract provided.


Synthesis, Characterization And Application Of Al,Fe-Pillared Clays, Zeljko D. Cupic Dec 2008

Synthesis, Characterization And Application Of Al,Fe-Pillared Clays, Zeljko D. Cupic

Zeljko D Cupic

No abstract provided.


The Privacy-Value-Control Harmonization For Rfid Adoption In Retail, Ben D. Renegar, K. Michael Dec 2008

The Privacy-Value-Control Harmonization For Rfid Adoption In Retail, Ben D. Renegar, K. Michael

Professor Katina Michael

Privacy concerns have, at least in part, impeded the adoption of radio frequency identification (RFID) in retail. The adoption of other automatic identification (auto-ID) applications shows that consumers often are willing to trade their privacy or their control of personal information against some value afforded by the application. In this paper, the interplay between privacy, value, and control is examined through a literature survey of four auto-ID applications: mobile phone, electronic toll collection, e-passports, and loyalty programs. The consumer value proposition for the use of RFID in retail is investigated through an online survey exploring end-user perceptions. The results of …


Improving Peer-To-Peer Search Performance Through Intelligent Social Search, Stephen J.H. Yang, Jia Zhang, L. Lin, Jeffrey J.P. Tsai Dec 2008

Improving Peer-To-Peer Search Performance Through Intelligent Social Search, Stephen J.H. Yang, Jia Zhang, L. Lin, Jeffrey J.P. Tsai

Jia Zhang

No abstract provided.


Overturning Instability In The Mesosphere And Lower Thermosphere: Analysis Of Instability Conditions In Lidar Data, Lucas Hurd, Miguel F. Larsen, Alan Z. Liu Dec 2008

Overturning Instability In The Mesosphere And Lower Thermosphere: Analysis Of Instability Conditions In Lidar Data, Lucas Hurd, Miguel F. Larsen, Alan Z. Liu

Alan Z Liu

No abstract provided.


Gravity Wave Propagation And Dissipation From The Stratosphere To The Lower Thermosphere, Xian Lu, Alan Z. Liu, Gary R. Swenson, Tao Li Dec 2008

Gravity Wave Propagation And Dissipation From The Stratosphere To The Lower Thermosphere, Xian Lu, Alan Z. Liu, Gary R. Swenson, Tao Li

Alan Z Liu

No abstract provided.


A Model Study Of The Effects Of Winds On Concentric Rings Of Gravity Waves From A Convective Plume Near Fort Collins On 11 May 2004, Sharon L. Vadas, Jia Yue, Chiao-Yao She, Peter A. Stamus, Alan Z. Liu Dec 2008

A Model Study Of The Effects Of Winds On Concentric Rings Of Gravity Waves From A Convective Plume Near Fort Collins On 11 May 2004, Sharon L. Vadas, Jia Yue, Chiao-Yao She, Peter A. Stamus, Alan Z. Liu

Alan Z Liu

No abstract provided.


Estimate Eddy Diffusion Coefficients From Gravity Wave Vertical Momentum And Heat Fluxes, Alan Z. Liu Dec 2008

Estimate Eddy Diffusion Coefficients From Gravity Wave Vertical Momentum And Heat Fluxes, Alan Z. Liu

Alan Z Liu

No abstract provided.


Sources Of Gravity Waves In The Lower Stratosphere Above South Pole, Zhenhua Li, Walter A. Robinson, Alan Z. Liu Dec 2008

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

Alan Z Liu

No abstract provided.


Suitability Assessment Of Water Quality Of Shinta River And Its Impacts On The Users: A Case Study From Gondar, Ethiopia, Mohammad Mansoob Khan Dr, H. R. Sharma Dr Dec 2008

Suitability Assessment Of Water Quality Of Shinta River And Its Impacts On The Users: A Case Study From Gondar, Ethiopia, Mohammad Mansoob Khan Dr, H. R. Sharma Dr

Dr. Mohammad Mansoob Khan

No abstract provided.


Constraint Handling Using Tournament Selection: Abductive Inference In Partly Deterministic Bayesian Network, Severino F. Galan, Ole J. Mengshoel Dec 2008

Constraint Handling Using Tournament Selection: Abductive Inference In Partly Deterministic Bayesian Network, Severino F. Galan, Ole J. Mengshoel

Ole J Mengshoel

Constraints occur in many application areas of interest to evolutionary computation. The area considered here is Bayesian networks (BNs), which is a probability-based method for representing and reasoning with uncertain knowledge. This work deals with constraints in BNs and investigates how tournament selection can be adapted to better process such constraints in the context of abductive inference. Abductive inference in BNs consists of finding the most probable explanation given some evidence. Since exact abductive inference is NP-hard, several approximate approaches to this inference task have been developed. One of them applies evolutionary techniques in order to find optimal or close-to-optimal …


Methods For Probabilistic Fault Diagnosis: An Electrical Power System Case Study, Brian Ricks, Ole J. Mengshoel Dec 2008

Methods For Probabilistic Fault Diagnosis: An Electrical Power System Case Study, Brian Ricks, Ole J. Mengshoel

Ole J Mengshoel

Health management systems that more accurately and quickly diagnose faults that may occur in different technical systems on-board a vehicle will play a key role in the success of future NASA missions. We discuss in this paper the diagnosis of abrupt continuous (or parametric) faults within the context of probabilistic graphical models, more specifically Bayesian networks that are compiled to arithmetic circuits. This paper extends our previous research, within the same probabilistic setting, on diagnosis of abrupt discrete faults. Our approach and diagnostic algorithm ProDiagnose are domain-independent; however we use an electrical power system testbed called ADAPT as a case …


Multilayered Structures In The Ionosphere F2 Region And Impulse-Like Increase Of The Nightglow Red 630 Nm Line Intensity As A Result Of Influence Of Shear Excited Atmospheric Vortical Perturbations, G. G. Didebulidze, Levan Lomidze, N. B. Gudadze, M. Todua Dec 2008

Multilayered Structures In The Ionosphere F2 Region And Impulse-Like Increase Of The Nightglow Red 630 Nm Line Intensity As A Result Of Influence Of Shear Excited Atmospheric Vortical Perturbations, G. G. Didebulidze, Levan Lomidze, N. B. Gudadze, M. Todua

Levan Lomidze

It is shown that the formation of multilayered structures in the midlatitude ionosphere F 2 layer can be caused by atmospheric vortical perturbation (shear wave) evolving in the meridional wind with linear zonal shear and can be accompanied by an impulse-like increase (with duration about 1–3 h) in the red 630 nm line total nightglow intensity. The shear wave can produce an enhancement of the northward wind (or decrease in the southward one), which can cause a downward motion of the F 2 layer peak height resulting in the impulse-like increase in the red line intensity. An important increase in …


Polylingual Topic Models, David Mimno, Hanna M. Wallach, Jason Naradowsky, David A. Smith, Andrew Mccallum Dec 2008

Polylingual Topic Models, David Mimno, Hanna M. Wallach, Jason Naradowsky, David A. Smith, Andrew Mccallum

Hanna M. Wallach

Topic models are a useful tool for analyzing large text collections, but have previously been applied in only monolingual, or at most bilingual, contexts. Meanwhile, massive collections of interlinked documents in dozens of languages, such as Wikipedia, are now widely available, calling for tools that can characterize content in many languages. We introduce a polylingual topic model that discovers topics aligned across multiple languages. We explore the model's characteristics using two large corpora, each with over ten different languages, and demonstrate its usefulness in supporting machine translation and tracking topic trends across languages.


Characterization Of Unknown Genetic Modifications Using High Throughput Sequencing And Computational Subtraction, Torstein Tengs Dec 2008

Characterization Of Unknown Genetic Modifications Using High Throughput Sequencing And Computational Subtraction, Torstein Tengs

Dr. Torstein Tengs

Background

When generating a genetically modified organism (GMO), the primary goal is to give a target organism one or several novel traits by using biotechnology techniques. A GMO will differ from its parental strain in that its pool of transcripts will be altered. Currently, there are no methods that are reliably able to determine if an organism has been genetically altered if the nature of the modification is unknown.

Results

We show that the concept of computational subtraction can be used to identify transgenic cDNA sequences from genetically modified plants. Our datasets include 454-type sequences from a transgenic line of …


Landscape: Representing And Interpreting The World, Karen M. Morin Dec 2008

Landscape: Representing And Interpreting The World, Karen M. Morin

Karen M. Morin

No abstract provided.


Are (The Log-Odds Of) Hospital Mortality Rates Normally Distributed In Ontario? Implications For Studying Variations In Outcomes Of Medical Care, Peter C. Austin Dec 2008

Are (The Log-Odds Of) Hospital Mortality Rates Normally Distributed In Ontario? Implications For Studying Variations In Outcomes Of Medical Care, Peter C. Austin

Peter Austin

Objective: Hierarchical regression models are used to examine variations in outcomes following the provision of medical care across providers. These models frequently assume a normal distribution for the provider-specific random effects. Poincaré said, “Everyone believes in the normal law, the experimenters because they imagine it a mathematical theorem, and the mathematicians because they think it an experimental fact”. Our objective was to examine the appropriateness of this assumption when examining variations in mortality.

Study design and setting: We used Bayesian model selection methods to compare hierarchical regression models in which the provider-specific random effects were either a normal distribution or …