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

Physical Sciences and Mathematics Commons™

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

2005

Discipline
Institution
Keyword
Publication
Publication Type
File Type

Articles 271 - 300 of 4759

Full-Text Articles in Physical Sciences and Mathematics

Electrochemical Oxidation Of Organic Additives In Tin Plating Electrolytes, Yin-Mei Cheng, Lan-Kun Cai, Qiang Song Nov 2005

Electrochemical Oxidation Of Organic Additives In Tin Plating Electrolytes, Yin-Mei Cheng, Lan-Kun Cai, Qiang Song

Journal of Electrochemistry

Cyclic voltammetry(CV) was used to characterize the voltammetric behaviours of organic additives, e.g. PSA(phenolsulfonic acid) EN(ethoxylatedα-naphthol) and ENSA(ethoxylatedα-naphthol sulfonic acid), on the anode surface. In PSA solutions, an anodic peak was obtained and the peak potential was about 1.2V. In EN and ENSA solutions, two anodic peaks were obtained and the peak potentials were about(0.95V) and 1.3V. The products of galvanostatic electrolysis were separated by HPLC(high performance liquid chromatography) and analyzed by EI/MS(electron ionizing mass spectrometry). The mechnism of the electrochemical oxidation was also disussed.

Go to article

Ontoqa: Metric-Based Ontology Quality Analysis, Samir Tartir, I. Budak Arpinar, Michael Moore, Amit P. Sheth, Boanerges Aleman-Meza Nov 2005

Ontoqa: Metric-Based Ontology Quality Analysis, Samir Tartir, I. Budak Arpinar, Michael Moore, Amit P. Sheth, Boanerges Aleman-Meza

Kno.e.sis Publications

As the Semantic Web gains importance for sharing knowledge on the Internet this has lead to the development and publishing of many ontologies in different domains. When trying to reuse existing ontologies into their applications, users are faced with the problem of determining if an ontology is suitable for their needs. In this paper, we introduce OntoQA, an approach that analyzes ontology schemas and their populations (i.e. knowledgebases) and describes them through a well defined set of metrics. These metrics can highlight key characteristics of an ontology schema as well as its population and enable users to make an informed …

Go to article

C-Terminal Tail Residue Arg1400 Enables Nadph To Regulate Electron Transfer In Neuronal Nitric-Oxide Synthase, Mauro Tiso, David Konas, Koustubh Panda, Elsa D. Garcin, Manisha Sharma, Elizabeth D. Getzoff, Dennis J. Stuehr Nov 2005

C-Terminal Tail Residue Arg1400 Enables Nadph To Regulate Electron Transfer In Neuronal Nitric-Oxide Synthase, Mauro Tiso, David Konas, Koustubh Panda, Elsa D. Garcin, Manisha Sharma, Elizabeth D. Getzoff, Dennis J. Stuehr

Department of Chemistry and Biochemistry Faculty Scholarship and Creative Works

The neuronal nitric-oxide synthase (nNOS) flavoprotein domain (nNOSr) contains regulatory elements that repress its electron flux in the absence of bound calmodulin (CaM). The repression also requires bound NADP(H), but the mechanism is unclear. The crystal structure of a CaM-free nNOSr revealed an ionic interaction between Arg1400 in the C-terminal tail regulatory element and the 2′-phosphate group of bound NADP(H). We tested the role of this interaction by substituting Ser and Glu for Arg1400 in nNOSr and in the full-length nNOS enzyme. The CaM-free nNOSr mutants had cytochrome c reductase activities that were less repressed than in wild-type, and this …

Go to article

Search For BS0→Μ+Μ- And BD0→Μ+Μ- Decays In PΡ̅ Collisions With Cdf Ii, A. Abulencia, Kenneth A. Bloom, Collider Detector At Fermilab Collaboration Nov 2005

Search For BS0→Μ+Μ- And BD0→Μ+Μ- Decays In PΡ̅ Collisions With Cdf Ii, A. Abulencia, Kenneth A. Bloom, Collider Detector At Fermilab Collaboration

Kenneth Bloom Publications

We report on a search for Bs0→µ+µ- and Bd0→µ+µ- decays in pρ̅ collisions at √8=1.96 TeV using 364 pb-1 of data collected by the CDF II detector at the Fermilab Tevatron Collider. After applying all selection requirements, we observe no candidates inside the Bs0 or Bd0 mass windows. The resulting upper limits on the branching fractions are Ɓ (Bs0→µ+µ-)<1.5×10-7 and Ɓ (Bd0→µ+µ-)<3.9×10-8 at 90% confidence level.

Go to article

Performance Of A C4f8o Gas Radiator Ring Imaging Cherenkov Detector Using Multi-Anode Photomultiplier Tubes, Raymond Mountain, Marina Artuso, Chaouki Boulahouache, S. Blusk Nov 2005

Performance Of A C4f8o Gas Radiator Ring Imaging Cherenkov Detector Using Multi-Anode Photomultiplier Tubes, Raymond Mountain, Marina Artuso, Chaouki Boulahouache, S. Blusk

Physics - All Scholarship

We report on test results of a novel ring imaging Cherenkov (RICH) detection system consisting of a 3 meter long gaseous C4F8O radiator, a focusing mirror, and a photon detector array based on Hamamatsu multi-anode photomultiplier tubes. This system was developed to identify charged particles in the momentum range from 3-70 GeV/c for the BTeV experiment.

Go to article

Roadmap Query For Sensor Network Assisted Navigation In Dynamic Environments, Sangeeta Bhattacharya, Nuzhet Atay, Gazihan Alankus, Chenyang Lu, O. Burchan Bayazit, Gruia-Catalin Roman Nov 2005

Roadmap Query For Sensor Network Assisted Navigation In Dynamic Environments, Sangeeta Bhattacharya, Nuzhet Atay, Gazihan Alankus, Chenyang Lu, O. Burchan Bayazit, Gruia-Catalin Roman

All Computer Science and Engineering Research

Autonomous mobile entity navigation through dynamic and unknown environments is an essential part of many mission critical applications like search and rescue and fire fighting. The dynamism of the environment necessitates the mobile entity to constantly maintain a high degree of awareness of the changing environment. This criteria makes it difficult to achieve good navigation performance by using just on-board sensors and existing navigation methods and motivates the use of wireless sensor networks (WSNs) to aid navigation. In this paper, we present a novel approach that integrates a roadmap based navigation algorithm with a novel network query protocol called Roadmap …

Go to article

Process For The Preparation Of Citalopram Intermediate, Aslam A. Malik, Hasan Palandoken, Joy A. Stringer, Dershing Huang, Antonio Romero, Olivier Dapremont Nov 2005

Process For The Preparation Of Citalopram Intermediate, Aslam A. Malik, Hasan Palandoken, Joy A. Stringer, Dershing Huang, Antonio Romero, Olivier Dapremont

Chemistry and Biochemistry

The present invention provides, inter alia, a novel process for the preparation of Citalopram, a known antidepressant.

Go to article

Generating Data-Extraction Ontologies By Example, Yuanqiu Zhou Nov 2005

Generating Data-Extraction Ontologies By Example, Yuanqiu Zhou

Theses and Dissertations

Ontology-based data-extraction is a resilient web data-extraction approach. A major limitation of this approach is that ontology experts must manually develop and maintain data-extraction ontologies. The limitation prevents ordinary users who have little knowledge of conceptual models from making use of this resilient approach. In this thesis we have designed and implemented a general framework, OntoByE, to generate data-extraction ontologies semi-automatically through a small set of examples collected by users. With the assistance of a limited amount of prior knowledge, experimental evidence shows that OntoByE is capable of interacting with users to generate data-extraction ontologies for domains of interest to …

Go to article

Second Oh Overtone Excitation And Statistical Dissociation Dynamics Of Peroxynitrous Acid, I. M. Konen, E. X.J. Li, Thomas Alex Stephenson, M. I. Lester Nov 2005

Second Oh Overtone Excitation And Statistical Dissociation Dynamics Of Peroxynitrous Acid, I. M. Konen, E. X.J. Li, Thomas Alex Stephenson, M. I. Lester

Chemistry & Biochemistry Faculty Works

The second OH overtone transition of the trans-perp conformer of peroxynitrous acid (tp-HOONO) is identified using infrared action spectroscopy. HOONO is produced by the recombination of photolytically generated OH and NO(2) radicals, and then cooled in a pulsed supersonic expansion. The second overtone transition is assigned to tp-HOONO based on its vibrational frequency (10 195.3 cm(-1)) and rotational band contour, which are in accord with theoretical predictions and previous observations of the first overtone transition. The transition dipole moment associated with the overtone transition is rotated considerably from the OH bond axis, as evident from its hybrid band composition, indicating …

Go to article

Group Scheduling In Selinux To Mitigate Cpu-Focused Denial Of Service Attacks, Armando Migliaccio, Terry Tidwell, Christopher Gill, Tejasvi Aswathanarayana, Douglas Niehaus Nov 2005

Group Scheduling In Selinux To Mitigate Cpu-Focused Denial Of Service Attacks, Armando Migliaccio, Terry Tidwell, Christopher Gill, Tejasvi Aswathanarayana, Douglas Niehaus

All Computer Science and Engineering Research

Popular security techniques such as public-private key encryption, firewalls, and role-based access control offer significant protec-tion of system data, but offer only limited protection of the computations using that data from significant interference due to accident or adversarial attack. However, in an increasing number of modern systems, ensuring the reliable execution of system activities is every bit as important as ensuring data security. This paper makes three contributions to the state of the art in protection of the execution of system activities from accidental or adversarial interference. First, we consider the motivating problem of CPU-focused denial of service attacks, and …

Go to article

Marketing Military Service Benefits Segmentation Based On Generalized And Restricted Exchange, Caroline Fisher, Kimball P. Marshall Nov 2005

Marketing Military Service Benefits Segmentation Based On Generalized And Restricted Exchange, Caroline Fisher, Kimball P. Marshall

Business and Information Technology Faculty Research & Creative Works

Willingness to engage in exchange is based on desired benefits. In typical commercial transactions, restricted exchange benefits dominate. However, public policy, social marketing situations might require consideration of both restricted and generalized exchange benefits. Applying factor analysis, cluster analysis and cross-tabulation, this paper reports research that has successfully segmented a young adult target market regarding interest in military service based on considerations of generalized and restricted exchange motivations. This research contributes to a growing body of literature on generalized exchange as a key conceptual element for social marketing. Results demonstrate the utility of the generalized exchange concept in identifying amarket …

Go to article

Freshwater Mussel Survey Of The 39-Mile District - Missouri National Recreational River, South Dakota And Nebraska, Jeff Shearer, Doug Backlund, Stephen K. Wilson Nov 2005

Freshwater Mussel Survey Of The 39-Mile District - Missouri National Recreational River, South Dakota And Nebraska, Jeff Shearer, Doug Backlund, Stephen K. Wilson

School of Natural Resources: Faculty Publications

Freshwater mussel (Bivalvia: Unionida) surveys were conducted on the 39-Mile District of the Missouri National Recreational River (MNRR) between Ft. Randall Dam, South Dakota and Running Water, South Dakota from October 2004 to September 2005. Fortynine locations within the 39-Mile District were inspected for the presence of mussel populations. Mussels (live individuals or dead shells) were collected at only 37% (18 of 49) of the sites. Of the seven mussel species collected during this survey, the fragile papershell Leptodea fragilis and pink papershell otamilus ohiensis were the most common. The paper pondshell Utterbackia imbecillis and mapleleaf Quadrula quadrula were rare …

Go to article

Acoustics Of The Salt Lake Tabernacle: Characterization And Study Of Spatial Variation, Sarah Rollins Nov 2005

Acoustics Of The Salt Lake Tabernacle: Characterization And Study Of Spatial Variation, Sarah Rollins

Theses and Dissertations

In order to preserve the acoustics of the Salt Lake Tabernacle after the seismic renovation of 2005-2006, it was necessary to characterize these acoustics immediately preceding the renovation. This thesis discusses the characterization process that began with the measurement of hundreds of impulse responses for five different source positions and several receiver locations throughout the hall seating areas. The acoustics were further characterized by deriving various parameters from these responses that correlate with subjective preferences for music and speech. Impulse responses were also generated by a CATT-Acoustic™ computer model of the Tabernacle for the same purpose. The parameter values were …

Go to article

A Software Development Environment For Building Context-Aware Systems For Family Technology, Jeremiah Kenton Jones Nov 2005

A Software Development Environment For Building Context-Aware Systems For Family Technology, Jeremiah Kenton Jones

Theses and Dissertations

The purpose of this thesis was to utilize existing technologies to create a development environment suitable for creating context-aware applications and systems specific to home and family living conditions. After outlining the history of context-aware applications and the challenges that face family-centric systems in this field, a development environment was implemented that solves the unique challenges that face application development for family-centric, context-aware applications. In particular, research cited in this document indicates that a browser-based user interface is the most appropriate interface for a family environment. The flexibility of the interface, as well as the familiarity of the application structure …

Go to article

Results Of Vadose Zone Sampling Within The Tri-Basin Natural Resources District, Mark E. Burbach Nov 2005

Results Of Vadose Zone Sampling Within The Tri-Basin Natural Resources District, Mark E. Burbach

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

Go to article

The Compression Of Dark Matter Halos By Baryonic Infall, Stacy S. Mcgaugh Nov 2005

The Compression Of Dark Matter Halos By Baryonic Infall, Stacy S. Mcgaugh

Faculty Scholarship

The initial radial density profiles of dark matter halos are laid down by gravitational collapse in hierarchical structure formation scenarios and are subject to further compression as baryons cool and settle to the halo centers. Here we describe an explicit implementation of the algorithm, originally developed by Young, to calculate changes to the density profile as the result of adiabatic infall in a spherical halo model. Halos with random motion are more resistant to compression than are those in which random motions are neglected, which is a key weakness of the simple method widely employed. Young's algorithm results in density …

Go to article

Charge-Exchange Spectra Of Hydrogenic And He-Like Iron, B. J. Wargelin, P. Beiersdorfer, P. A. Neill, Ronald E. Olson, J. H. Scofield Nov 2005

Charge-Exchange Spectra Of Hydrogenic And He-Like Iron, B. J. Wargelin, P. Beiersdorfer, P. A. Neill, Ronald E. Olson, J. H. Scofield

Physics Faculty Research & Creative Works

We present H-like Fe XXVI and He-like Fe XXV charge-exchange spectra resulting from collisions of highly charged iron with N2 gas at an energy of ∼10 eV amu-1 in an electron beam ion trap. Although individual high-n emission lines are not resolved in our measurements, we observe that the most likely level for Fe+25 → Fe+24 electron capture is nmax ∼ 9, in line with expectations, while the most likely value for Fe+26 → Fe+25 charge exchange is significantly higher. in the Fe XXV spectrum, the Kα emission feature dominates, whether produced via charge exchange …

Go to article

Dq Herculis In Profile: Whole Earth Telescope Observations And Smoothed Particle Hydrodynamics Simulations Of An Edge-On Cataclysmic Variable System, Matt A. Wood Nov 2005

Dq Herculis In Profile: Whole Earth Telescope Observations And Smoothed Particle Hydrodynamics Simulations Of An Edge-On Cataclysmic Variable System, Matt A. Wood

Aerospace, Physics, and Space Science Faculty Publications

The old nova DQ Herculis was the Whole Earth Telescope Northern Hemisphere target for the 1997 July campaign and was observed on four nights with the SARA 0.9 m telescope during 2003 June. We present updated ephemerides for the eclipse and 71 s timings. The Fourier transform displays power at the presumed white dwarf spin period of 71.0655 s, but no significant power at either 142 or 35.5 s. The mean pulsed light curve is obtained by folding on the orbital period modulus the mean ephemeris of the 71 s period, and from this we calculate an O - C …

Go to article

Diversity Of Methanogens And Other Archaea In Permanently Cold, Anoxic Marine Sediments, Melissa Mary Kendell Nov 2005

Diversity Of Methanogens And Other Archaea In Permanently Cold, Anoxic Marine Sediments, Melissa Mary Kendell

Dissertations and Theses

Little is known about the mechanism of methanogenic degradation of acetate or the fate of hydrogen and formate in cold marine sediments, or the ability of methanogens to grow and produce methane there. We used cultivation and molecular techniques to examine the microbes that produce methane from these substrates in permanently cold, anoxic marine sediments at Skan Bay, Alaska (57°N, 167°W, depth 65 m), at the Nankai Trough (32°21'N, 134°56'E, depth 247 m), and at Hydrate Ridge, Oregon (44°35'N, 125°10'W, depth 800 m). Most probable number (MPN) analyses were conducted for CO2-reducing, methylotrophic, and aceticlastic methanogens from Skan Bay and …

Go to article

Low Magnetic Prandtl Number Dynamos With Helical Forcing, Pablo D. Mininni, David C. Montgomery Nov 2005

Low Magnetic Prandtl Number Dynamos With Helical Forcing, Pablo D. Mininni, David C. Montgomery

Dartmouth Scholarship

We present direct numerical simulations of dynamo action in a forced Roberts flow. The behavior of the dynamo is followed as the mechanical Reynolds number is increased, starting from the laminar case until a turbulent regime is reached. The critical magnetic Reynolds for dynamo action is found, and in the turbulent flow it is observed to be nearly independent on the magnetic Prandtl number in the range from ∼0.3 to ∼0.1. Also the dependence of this threshold with the amount of mechanical helicity in the flow is studied. For the different regimes found, the configuration of the magnetic and velocity …

Go to article

Measuring The Expression Of Hypovirulence In A Segregating Population Of Bc2f2 Castanea Dentata Hybrids, Lisa Michelle Worthen Nov 2005

Measuring The Expression Of Hypovirulence In A Segregating Population Of Bc2f2 Castanea Dentata Hybrids, Lisa Michelle Worthen

Honors Theses

The American chestnut tree (Castanea dentata) was reduced from an important canopy hardwood to an understory shrub by the chestnut blight fungus (Cryphonectria parasitica). Hypovirulence, a phenomenon whereby Cryphonectria parasitica is weakened in its ability to incite chestnut blight, is caused by doublestranded RNA (dsRNA) molecules of viral origin in the cytoplasm of the fungus.Hypovirulence serves as a biological control of C. parasitica in Europe and small, isolated areas in North America, but has not been an effective, widespread biological control in North America. It has been hypothesized that the moderately higher levels of host resistance of the European chestnut …

Go to article

Principal Component Analysis For Predicting Transcription-Factor Binding Motifs From Array-Derived Data, Yunlong Liu, Matthew P Vincenti, Hiroki Yokota Nov 2005

Principal Component Analysis For Predicting Transcription-Factor Binding Motifs From Array-Derived Data, Yunlong Liu, Matthew P Vincenti, Hiroki Yokota

Dartmouth Scholarship

The responses to interleukin 1 (IL-1) in human chondrocytes constitute a complex regulatory mechanism, where multiple transcription factors interact combinatorially to transcription-factor binding motifs (TFBMs). In order to select a critical set of TFBMs from genomic DNA information and an array-derived data, an efficient algorithm to solve a combinatorial optimization problem is required. Although computational approaches based on evolutionary algorithms are commonly employed, an analytical algorithm would be useful to predict TFBMs at nearly no computational cost and evaluate varying modelling conditions. Singular value decomposition (SVD) is a powerful method to derive primary components of a given matrix. Applying SVD …

Go to article

Classifcation Of Conics In The Tropical Projective Plane, Amanda Ellis Nov 2005

Classifcation Of Conics In The Tropical Projective Plane, Amanda Ellis

Theses and Dissertations

This paper defines tropical projective space, TP^n, and the tropical general linear group TPGL(n). After discussing some simple examples of tropical polynomials and their hypersurfaces, a strategy is given for finding all conics in the tropical projective plane. The classification of conics and an analysis of the coefficient space corresponding to such conics is given.

Go to article

Sun In The Spectroscopic Binary Im Pegasi, The Guide Star For The Gravity Probe B Mission, Stephen C. Marsden, Svetlana Berdyugina, Jean-Francois Donati, Joel A. Eaton, Michael H. Williamson, Ilya Ilyin, Debra A. Fischer, Melesio Muñoz, Howard Isaacson, M. I. Ratner, Meïr Semel, Pascal Petit, Brad D. Carter Nov 2005

Sun In The Spectroscopic Binary Im Pegasi, The Guide Star For The Gravity Probe B Mission, Stephen C. Marsden, Svetlana Berdyugina, Jean-Francois Donati, Joel A. Eaton, Michael H. Williamson, Ilya Ilyin, Debra A. Fischer, Melesio Muñoz, Howard Isaacson, M. I. Ratner, Meïr Semel, Pascal Petit, Brad D. Carter

Information Systems and Engineering Management Research Publications

We present the first detection of the secondary of the spectroscopic binary system IM Pegasi (HR 8703), the guide star for the NASA-Stanford relativity gyroscope mission Gravity Probe B. In support of this mission, high-resolution echelle spectra of IM Peg have been obtained on an almost nightly basis. Applying the technique of least-squares deconvolution, we achieve very high signal-to-noise ratio line profiles and detect the orbit of the secondary of the system. Combining almost 700 new radial velocity measurements of both the primary and secondary of the system with previous measurements, we derive improved orbital parameters of the IM Peg …

Go to article

Nonparametric Estimation Of Bivariate Failure Time Associations In The Presence Of A Competing Risk, Karen Bandeen-Roche, Jing Ning Nov 2005

Nonparametric Estimation Of Bivariate Failure Time Associations In The Presence Of A Competing Risk, Karen Bandeen-Roche, Jing Ning

Johns Hopkins University, Dept. of Biostatistics Working Papers

There has been much research on the study of associations among paired failure times. Most has either assumed time invariance of association or been based on complex measures or estimators. Little has accommodated failures arising amid competing risks. This paper targets the conditional cause specific hazard ratio, a recent modification of the conditional hazard ratio to accommodate competing risks data. Estimation is accomplished by an intuitive, nonparametric method that localizes Kendall’s tau. Time variance is accommodated through a partitioning of space into “bins” between which the strength of association may differ. Inferential procedures are researched, small sample performance evaluated, and …

Go to article

Nanomesa And Nanowell Formation In Langmuir–Blodgett Polyvinylidene Fluoride Trifluoroethylene Copolymer Films, Jiangyu Li, Yang Luo, Mengjun Bai, Stephen Ducharme Nov 2005

Nanomesa And Nanowell Formation In Langmuir–Blodgett Polyvinylidene Fluoride Trifluoroethylene Copolymer Films, Jiangyu Li, Yang Luo, Mengjun Bai, Stephen Ducharme

Department of Physics and Astronomy: Faculty Publications

In this letter, we report an energetics-based model to explain the self-organizing nanomesa and nanowell patterns recently observed in Langmuir-Blodgett (LB) films of polyvinylidene fluoride trifluoroethylene [P(VDF-TrFE)] copolymers. The feature size of nanomesas and nanowells has been estimated using a linear stability analysis, and the morphology of the nanomesas and nanowells has been revealed by the numerical simulation, both in good agreement with experiments. A number of other model predictions regarding the nanomesa and nanowell formation also agree with experimental observations. The model can be used to guide the design and optimization of nanostructures in the P(VDF-TrFE) LB films and …

Go to article

The Role Of Phosducin-Like Protein And The Cytosolic Chaperonin Cct In G Beta Gamma Dimer Assembly, Ting Hu Nov 2005

The Role Of Phosducin-Like Protein And The Cytosolic Chaperonin Cct In G Beta Gamma Dimer Assembly, Ting Hu

Theses and Dissertations

Phosducin-like protein (PhLP), a G protein beta gamma subunit dimer binder and G protein signaling regulator, was suggested to regulate the activity of cytosolic chaperonin CCT by their high affinity interaction. In the present study, the three-dimensional structure of PhLP:CCT complex has been solved by cryoelectron microscopy. PhLP was found to bind only one of the chaperonin rings with both N- and C-terminal domains. It spans the central folding cavity of CCT and interacts with two opposite sides of the top apical region, inducing the constraining of the entry of the folding cavity. These findings support a putative role of …

Go to article

Progress Towards Terahertz Acoustic Phonon Generation In Doping Superlattices, Thomas E. Wilson Nov 2005

Progress Towards Terahertz Acoustic Phonon Generation In Doping Superlattices, Thomas E. Wilson

Physics Faculty Research

Progress is described in experiments to generate coherent terahertz acoustic phonons in silicon doping superlattices by the resonant absorption of nanosecond-pulsed far-infrared laser radiation. Future experiments are proposed that would use the superlattice as a transducer in a terahertz cryogenic acoustic reflection microscope with sub-nanometer resolution.

Go to article

Correspondences Between Regression Models For Complex Binary Outcomes And Those For Structured Multivariate Survival Analyses, Nicholas P. Jewell Nov 2005

Correspondences Between Regression Models For Complex Binary Outcomes And Those For Structured Multivariate Survival Analyses, Nicholas P. Jewell

U.C. Berkeley Division of Biostatistics Working Paper Series

Doksum and Gasko [5] described a one-to-one correspondence between regression models for binary outcomes and those for continuous time survival analyses. This correspondence has been exploited heavily in the analysis of current status data (Jewell and van der Laan [11], Shiboski [18]). Here, we explore similar correspondences for complex survival models and categorical regression models for polytomous data. We include discussion of competing risks and progressive multi-state survival random variables.

Go to article

Application Of A Variable Importance Measure Method To Hiv-1 Sequence Data, Merrill D. Birkner, Mark J. Van Der Laan Nov 2005

Application Of A Variable Importance Measure Method To Hiv-1 Sequence Data, Merrill D. Birkner, Mark J. Van Der Laan

U.C. Berkeley Division of Biostatistics Working Paper Series

van der Laan (2005) proposed a method to construct variable importance measures and provided the respective statistical inference. This technique involves determining the importance of a variable in predicting an outcome. This method can be applied as an inverse probability of treatment weighted (IPTW) or double robust inverse probability of treatment weighted (DR-IPTW) estimator. A respective significance of the estimator is determined by estimating the influence curve and hence determining the corresponding variance and p-value. This article applies the van der Laan (2005) variable importance measures and corresponding inference to HIV-1 sequence data. In this data application, protease and reverse …

Go to article

First Prev Next Last