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2005

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Articles 31 - 60 of 4757

Full-Text Articles in Physical Sciences and Mathematics

Nonmetal Ordering In Tic1-Xnx: Ground-State Structure And The Effects Of Finite Temperature, Gus L. W. Hart, Brian Kolb Dec 2005

Nonmetal Ordering In Tic1-Xnx: Ground-State Structure And The Effects Of Finite Temperature, Gus L. W. Hart, Brian Kolb

Faculty Publications

The TiC1-xNx system has long been prized in industry because of its desirable thermodynamic and hardness characteristics. Previous studies have not produced comprehensive results describing the ordering tendencies of TiC1-xNx at any temperature. We apply the mixed-basis cluster expansion and Monte Carlo methods to the problem and find a fascinating array of ground-state structures occurring at precise nitrogen-concentration intervals of ∆x=1/16 and related to each other by simple (201) quasisuperlattice motifs. Thermodynamic Monte Carlo results indicate that the critical ordering temperatures at all concentrations are well below room temperature. short-range ordering develops at T ≈ 800 K and exhibits the …

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Observations Of Sand Waves, Megaripples, And Hummocks In The Dutch Coastal Area And Their Relation To Currents And Combined Flow Conditions, Sandra Passchier, Maarten Kleinhans Dec 2005

Observations Of Sand Waves, Megaripples, And Hummocks In The Dutch Coastal Area And Their Relation To Currents And Combined Flow Conditions, Sandra Passchier, Maarten Kleinhans

Department of Earth and Environmental Studies Faculty Scholarship and Creative Works

[1] This paper aims to investigate the distribution and stability of large‐scale bed forms in response to storm and fair‐weather conditions in a shallow marine environment. Multibeam and side‐scan sonar data off the Dutch coast (median grain size 0.25–0.35 mm) were collected to monitor sand waves (λ = 100–800 m) and superimposed megaripples (λ = 1–40 m) through multiple storm and fair‐weather events. Box cores were used to observe the vertical bed structure and grain size. In the Dutch coastal area, two‐dimensional (2‐D) megaripples (λ = 1–15 m) are the dominant bed forms in current‐dominated (>0.4 m/s) tidal flow …

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Monitoring Pc Hardware Sounds In Linux Systems Using The Daubechies D4 Wavelet., Robert Karns Henry Dec 2005

Monitoring Pc Hardware Sounds In Linux Systems Using The Daubechies D4 Wavelet., Robert Karns Henry

Electronic Theses and Dissertations

Users of high availability (HA) computing require systems that run continuously, with little or no downtime. Modern PCs address HA needs by monitoring operating system parameters such as voltage, temperature, and hard drive status in order to anticipate possible system failure. However, one modality for PC monitoring that has been underutilized is sound. The application described here uses wavelet theory to analyze sounds produced by PC hard drives during standard operation. When twenty-nine hard drives were tested with the application and the results compared with the drives' Self-Monitoring, Analysis, and Reporting Technology (S.M.A.R.T.) data, the binomial distribution's low p-value of …

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Assessing An Environmental Education Program, Gregory Schraw, Lori Olafson, Jeanne A. Klockow Dec 2005

Assessing An Environmental Education Program, Gregory Schraw, Lori Olafson, Jeanne A. Klockow

Presentations (DM)

We developed a comprehensive assessment plan and tested the curriculum to determine whether hands-on outdoor recreation events promote knowledge, attitudes, and performance among at-risk urban children. Knowledge, attitude, and performance assessments were developed, refined and implemented with a variety of age groups participating within the events. Findings revealed that knowledge, attitudes, and performance increased substantially as a result of participating in the outdoor recreation events.

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Using Prospect Theory To Investigate Decision-Making Bias Within An Information Security Context, Neil J. Schroeder Dec 2005

Using Prospect Theory To Investigate Decision-Making Bias Within An Information Security Context, Neil J. Schroeder

Theses and Dissertations

Information security is an issue that has increased in importance over the past decade. In this time both practitioner and academic circles have researched and developed practices and process to more effectively handle information security. Even with growth in these areas there has been little research conducted into how decision makers actually behave. This is problematic because decision makers in the Department of Defense have been observed exhibiting risk seeking behavior when making information security decisions that seemingly violate accepted norms. There are presently no models in the literature that provide sufficient insight into this phenomenon. This study used Prospect …

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Magnetic And Spectroscopic Characteristics Of Znmno System, Aswini K. Pradhan, D. Hunter, Kai Zhang, J.B. Dadson, S. Mohanty, T.M. Williams, K. Lord, R.R. Rakimhov, U.N. Roy, Y. Cui, A. Burger, Jun Zhang, David J. Sellmyer Dec 2005

Magnetic And Spectroscopic Characteristics Of Znmno System, Aswini K. Pradhan, D. Hunter, Kai Zhang, J.B. Dadson, S. Mohanty, T.M. Williams, K. Lord, R.R. Rakimhov, U.N. Roy, Y. Cui, A. Burger, Jun Zhang, David J. Sellmyer

David Sellmyer Publications

We report on the observation of room-temperature ferromagnetism in epitaxial (Zn,Mn)O films grown by a pulsed-laser deposition technique using high-density targets. The X-ray, microscopic, spectroscopic and magnetic properties of target material containing 6 at.% of Mn and films were compared. The target shows the presence of large clusters exhibiting paramagnetic behavior. However, ferromagnetic properties were observed in (Zn,Mn)O films grown at a substrate temperature of 500 °C and with an oxygen partial pressure of 1 mTorr. Although, crystalline quality of the film improves with increasing substrate temperature, the ferromagnetism becomes weaker.

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An Event-Based Approach To Validating Solar Wind Speed Predictions: High-Speed Enhancements In The Wang-Sheeley-Arge Model, M. J. Owens, C. N. Arge, Harlan E. Spence, A. Pembroke Dec 2005

An Event-Based Approach To Validating Solar Wind Speed Predictions: High-Speed Enhancements In The Wang-Sheeley-Arge Model, M. J. Owens, C. N. Arge, Harlan E. Spence, A. Pembroke

Physics & Astronomy

[1] One of the primary goals of the Center for Integrated Space Weather Modeling (CISM) effort is to assess and improve prediction of the solar wind conditions in near-Earth space, arising from both quasi-steady and transient structures. We compare 8 years of L1 in situ observations to predictions of the solar wind speed made by the Wang-Sheeley-Arge (WSA) empirical model. The mean-square error (MSE) between the observed and model predictions is used to reach a number of useful conclusions: there is no systematic lag in the WSA predictions, the MSE is found to be highest at solar minimum and lowest …

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Electromagnetism In Gravitational Collapse, Craig Ernest Skinfill Dec 2005

Electromagnetism In Gravitational Collapse, Craig Ernest Skinfill

Theses and Dissertations

A numerical approach to including electromagnetism with general relativity is developed using GRAXI as a starting point. We develop a mathematical model describing electromagnetism coupled to a scalar field in an evolving axisymmetric spacetime. As there are numerous formulations of electromagnetism, we evalute different formulations in a limited flat space case. The full curved space system is then developed, using the flat case as a guide to implementing electromagnetism. This model is then implemented using GRAXI as a code base.

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Laser-Controlled Local Magnetic Field With Semiconductor Quantum Rings, Yuriy V. Pershin Dr, Carlo Piermarocchi Dec 2005

Laser-Controlled Local Magnetic Field With Semiconductor Quantum Rings, Yuriy V. Pershin Dr, Carlo Piermarocchi

Faculty Publications

We analyze theoretically the dynamics of N electrons localized in a narrow semiconductor quantum ring under a train of phase-locked infrared laser pulses. The pulse sequence is designed to control the total angular momentum of the electrons. The quantum ring can be put in states characterized by strong currents. The local magnetic field created by these currents can be used for a selective quantum control of single spins in semiconductor systems. The current generation in quantum rings with finite width is also studied.

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(E)-9,10-Dihydro-9-Methyl-9-Nitro-10-(Trinitro­Meth­Yl)Anthracene, Mustafa Arslan, Ronald J. Baker, John Masnovi, Erol Asker Dec 2005

(E)-9,10-Dihydro-9-Methyl-9-Nitro-10-(Trinitro­Meth­Yl)Anthracene, Mustafa Arslan, Ronald J. Baker, John Masnovi, Erol Asker

Chemistry Faculty Publications

The title compound, C16H12N4O8, was prepared by the photochemical reaction of 9-methyl­anthracene and tetra­nitro­methane in dichloromethane. Intermolecula face-to-face π–π stacking inter­actions are present along the a axis.

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Spin-Photovoltaic Effect In Quantum Wires Due To Intersubband Transitions, Arkady Fedorov, Yuriy V. Pershin Dr, Carlo Piermarocchi Dec 2005

Spin-Photovoltaic Effect In Quantum Wires Due To Intersubband Transitions, Arkady Fedorov, Yuriy V. Pershin Dr, Carlo Piermarocchi

Faculty Publications

We consider the current induced in a quantum wire by external electromagnetic radiation. The photocurrent is caused by the interplay of spin-orbit interaction (Rashba and Dresselhaus terms) and an external in-plane magnetic field. We calculate this current using a Wigner functions approach, taking into account radiation-induced transitions between transverse subbands. The magnitude and the direction of the current depends on the Dresselhaus and Rashba constants, strength of magnetic field, radiation frequency, and intensity. The current can be controlled by changing some of these parameters.

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K-Hyponormality Of Multivariable Weighted Shifts, Raúl E. Curto, Sang Hoon Lee, Jasang Yoon Dec 2005

K-Hyponormality Of Multivariable Weighted Shifts, Raúl E. Curto, Sang Hoon Lee, Jasang Yoon

School of Mathematical & Statistical Sciences Faculty Publications

We characterize joint k-hyponormality for 2-variable weighted shifts. Using this characterization we construct a family of examples which establishes and illustrates the gap between k-hyponormality and (k+1) -hyponormality for each k ≥ 1. As a consequence, we obtain an abstract solution to the Lifting Problem for Commuting Subnormals.

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Rescattering Effects In The Multiphoton Regime, M. V. Frolov, A. V. Flegel, N. L. Manakov, Anthony F. Starace Dec 2005

Rescattering Effects In The Multiphoton Regime, M. V. Frolov, A. V. Flegel, N. L. Manakov, Anthony F. Starace

Anthony F. Starace Publications

LETTER TO THE EDITOR

The plateau features that characterize the low-frequency spectra of fundamental strong-field processes such as harmonic generation, above-threshold ionization and laser-assisted electron-atom scattering are shown to exist also for photon energies Eγ of the order of the energy |E0| of a bound electron. The existence of these rescattering effects in such a high-frequency (and thus nontunnelling) regime is supported by accurate quantum analyses of intense Ti-Sapphire laser interactions with halogen negative ions, for which Eγ ≈ 0.5|E0|.

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Kondo Resonances And Anomalous Gate Dependence In The Electrical Conductivity Of Single-Molecule Transistors, L H. Yu, Z K. Keane, Jacob W. Ciszek, L Cheng, J M. Tour, T Baruah, M R. Pederson, D Natelson Dec 2005

Kondo Resonances And Anomalous Gate Dependence In The Electrical Conductivity Of Single-Molecule Transistors, L H. Yu, Z K. Keane, Jacob W. Ciszek, L Cheng, J M. Tour, T Baruah, M R. Pederson, D Natelson

Chemistry: Faculty Publications and Other Works

We report Kondo resonances in the conduction of single-molecule transistors based on transition metal coordination complexes. We find Kondo temperatures in excess of 50 K, comparable to those in purely metallic systems. The observed gate dependence of the Kondo temperature is inconsistent with observations in semiconductor quantum dots and a simple single-dot-level model. We discuss possible explanations of this effect, in light of electronic structure calculations.

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Detecting Submarine Groundwater Discharge With Synoptic Surveys Of Sediment Resistivity, Radium, And Salinity, John A. Breier, Crystaline F. Breier, Henrietta Edmonds Dec 2005

Detecting Submarine Groundwater Discharge With Synoptic Surveys Of Sediment Resistivity, Radium, And Salinity, John A. Breier, Crystaline F. Breier, Henrietta Edmonds

School of Earth, Environmental, & Marine Sciences Faculty Publications

A synoptic geophysical and geochemical survey was used to investigate the occurrence and spatial distribution of submarine discharges of water to upper Nueces Bay, Texas. The 17 km survey incorporated continuous resistivity profiling; measurements of surface water salinity, temperature, and dissolved oxygen; and point measurements of dissolved Ra isotopes. The survey revealed areas of interleaving, vertical fingers of high and low conductivity extending up through 7 m of bay bottom sediments into the surface water, located within 100 m of surface salinity and dissolved Ra maxima along with peaks in water temperature and lows in dissolved oxygen. These results indicate …

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Tree Ring Dating Of Beams And Trusses In The Beall House, Wayne County Historical Society Wooster, Ohio Dec 2005

Tree Ring Dating Of Beams And Trusses In The Beall House, Wayne County Historical Society Wooster, Ohio

Historic Structures

Dating historical structures in Wayne County. The Historical Structures collection consists of reports that are the resoult of dendochronological analysis of timbers from structures in Pennsylvania and Ohio. Contributors: Lehman, Sophie; Wiles, Greg

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Conference Web Site Redesign, Steven M. Pisarski Dec 2005

Conference Web Site Redesign, Steven M. Pisarski

Regis University Student Publications (comprehensive collection)

Sustainable Resources was a non-profit organization based out of Boulder, CO that, at the time of this project hosted yearly conferences to help find solutions to world poverty. Although, the previous web site had a professional appearance, it was not meeting their needs with regards to usability, extensibility, and maintainability, as they had been forced to rely heavily on a transient volunteer IT labor base. The aim of this project was to address their functional and maintenance problems. The application's front-end was built in adherence to the Model -view-Controller (MVC) design pattern and implemented using the Jakarta Struts framework and …

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Tree Ring Dating Of Beams And Trusses In The Geiser House Forrer Road, Orrville, Ohio Dec 2005

Tree Ring Dating Of Beams And Trusses In The Geiser House Forrer Road, Orrville, Ohio

Historic Structures

Dating historical structures in Orrville, Ohio using dendrochronology.The Historical Structures collection consists of reports that are the result of dendochronological analysis of timbers from structures in Pennsylvania and Ohio. Contributors: Lehman, Sophie; Wiles, Greg

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A Multisite Photometric Campaign On The Pre-Main-Sequence ₰ Delta Scuti Pulsator Ip Per, V. Ripepi, T. D. Oswalt, S. Bernabei, M. Marconi, Et Al. Dec 2005

A Multisite Photometric Campaign On The Pre-Main-Sequence ₰ Delta Scuti Pulsator Ip Per, V. Ripepi, T. D. Oswalt, S. Bernabei, M. Marconi, Et Al.

Publications

We present the results of a photometric multisite campaign on the δ Scuti Pre-Main-Sequence star IP Per. Nine telescopes have been involved in the observations, with a total of about 190 h of observations over 38 nights. Present data confirms the multiperiodic nature of this star and leads to the identification of at least nine pulsational frequencies. Comparison with the predictions of linear non-adiabatic radial pulsation models allowed us to identify only five of the nine observed frequencies, and to constrain the position of IP Per in the HR diagram. The latter is in good agreement with the empirical determination …

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Ultracold Neutral Plasma Expansion In Two Dimensions, E. A. Cummings, J. E. Daily, Dallin S. Durfee, Scott D. Bergeson Dec 2005

Ultracold Neutral Plasma Expansion In Two Dimensions, E. A. Cummings, J. E. Daily, Dallin S. Durfee, Scott D. Bergeson

Faculty Publications

An isothermal model of ultracold neutral plasma expansion is extended to systems without spherical symmetry. It is used to interpret new fluorescence measurements on ultracold neutral calcium plasmas. For a self-similar expansion, the fluid equations are solved both analytically and numerically. The density and velocity solutions are used to predict fluorescence signals induced by a laser beam weakly focused into the plasma. Despite the simplicity of the model, predicted fluorescence signals reproduce major features of the experimental data

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Foundations Of Generalized Cwatsets, Jesse Beder Dec 2005

Foundations Of Generalized Cwatsets, Jesse Beder

Mathematical Sciences Technical Reports (MSTR)

We present a new, abstract definition for a generalized cwatset that produces notions of subcwatset and quotient cwatset that behave naturally. We use small cancellation theory to prove a result analogous to the statement that every group is isomorphic to some permutation group.

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Longitudinal Magnetic Field Changes Accompanying Solar Flares, Jeffrey J. Sudol, J. W. Harvey Dec 2005

Longitudinal Magnetic Field Changes Accompanying Solar Flares, Jeffrey J. Sudol, J. W. Harvey

Physics & Engineering Faculty Publications

No abstract provided.

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New Graph Model For Channel Assignment In Ad Hoc Wireless Networks, Maggie Xiaoyan Cheng, S. C. Huang, X. Huang, Weili Wu Dec 2005

New Graph Model For Channel Assignment In Ad Hoc Wireless Networks, Maggie Xiaoyan Cheng, S. C. Huang, X. Huang, Weili Wu

Computer Science Faculty Research & Creative Works

The channel assignment problem in ad hoc wireless networks is investigated. The problem is to assign channels to hosts in such a way that interference among hosts is eliminated and the total number of channels is minimised. Interference is caused by direct collisions from hosts that can hear each other or indirect collisions from hosts that cannot hear each other, but simultaneously transmit to the same destination. A new class of disk graphs (FDD: interFerence Double Disk graphs) is proposed that include both kinds of interference edges. Channel assignment in wireless networks is a vertex colouring problem in FDD graphs. …

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Structural Studies On A Mitochondrial Glyoxalase Ii, Gishanthi P. K. Marasinghe, Ian M. Sander, Brian Bennett, Gopal R. Periyannan, Ke-Wu Yang, Christopher A. Makaroff, Michael W. Crowder Dec 2005

Structural Studies On A Mitochondrial Glyoxalase Ii, Gishanthi P. K. Marasinghe, Ian M. Sander, Brian Bennett, Gopal R. Periyannan, Ke-Wu Yang, Christopher A. Makaroff, Michael W. Crowder

Physics Faculty Research and Publications

Glyoxalase 2 is a β-lactamase fold-containing enzyme that appears to be involved with cellular chemical detoxification. Although the cytoplasmic isozyme has been characterized from several organisms, essentially nothing is known about the mitochondrial proteins. As a first step in understanding the structure and function of mitochondrial glyoxalase 2 enzymes, a mitochondrial isozyme (GLX2-5) from Arabidopsis thaliana was cloned, overexpressed, purified, and characterized using metal analyses, EPR and 1H NMR spectroscopies, and x-ray crystallography. The recombinant enzyme was shown to bind 1.04 ± 0.15 eq of iron and 1.31 ± 0.05 eq of Zn(II) and to exhibit kcat and …

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Change Bell Ringing And Mathematics: A High School Student Excursion Into Graph Theory And Group Theory, Kristi Carlson Dec 2005

Change Bell Ringing And Mathematics: A High School Student Excursion Into Graph Theory And Group Theory, Kristi Carlson

Honors Theses

This unit was created as a way to introduce higher level mathematics concepts to advanced high school students. All five of the National Council of Teachers of Mathematics Process Standards are found in this unit. For most of the unit, students work within small groups

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Discovery And Characterization Of The Cryptic Psi Subunit Of The Pseudomonad Dna Replicase, Thale C. Jarvis, Amber A. Beaudry, James M. Bullard, Urs Ochsner, H. Garry Dallmann, Charles S. Mchenry Dec 2005

Discovery And Characterization Of The Cryptic Psi Subunit Of The Pseudomonad Dna Replicase, Thale C. Jarvis, Amber A. Beaudry, James M. Bullard, Urs Ochsner, H. Garry Dallmann, Charles S. Mchenry

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Chemistry)

We previously reconstituted a minimal DNA replicase from Pseudomonas aeruginosa consisting of α and ϵ (polymerase and editing nuclease), β (processivity factor), and the essential τ, δ, and δ′ components of the clamp loader complex (Jarvis, T., Beaudry, A., Bullard, J., Janjic, N., and McHenry, C. (2005) J. Biol. Chem. 280, 7890-7900). In Escherichia coli DNA polymerase III holoenzyme, χ and Ψ are tightly associated clamp loader accessory subunits. The addition of E. coli χΨ to the minimal P. aeruginosa replicase stimulated its activity, suggesting the existence of χ and Ψ counterparts in P. aeruginosa. The P. aeruginosa χ …

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Trust Broker: A Defense Against Identity Theft From Online Transactions, Michael George Edvalson Dec 2005

Trust Broker: A Defense Against Identity Theft From Online Transactions, Michael George Edvalson

Theses and Dissertations

The proliferation of online services over the years has encouraged more and more people to participate in Internet activities. Many web sites request personal and sensitive information needed to deliver the desired service. Unfortunately, it is difficult to distinguish the sites that can be trusted to protect such information from those that cannot. Many attempts to make the Internet easier to use introduce new security and privacy problems. On the other hand, most attempts at creating a safe online environment produce systems that are cryptic and hard to use. The TrustBroker system is based on a specialized online repository that …

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Estimation Of Iron Solubility From Observations And A Global Aerosol Model, Chao Luo, N. M. Mahowald, N. Meskhidze, Y. Chen, R. L. Siefert, A. R. Baker, Anne M. Johansen Dec 2005

Estimation Of Iron Solubility From Observations And A Global Aerosol Model, Chao Luo, N. M. Mahowald, N. Meskhidze, Y. Chen, R. L. Siefert, A. R. Baker, Anne M. Johansen

All Faculty Scholarship for the College of the Sciences

Mineral aerosol deposition is the dominant source of iron to the open ocean. Soil iron is typically insoluble and understanding the atmospheric processes that convert insoluble iron to the more soluble forms observed over the oceans is crucial. In this paper, we model several proposed processes for the conversion of Fe(III) to Fe(II), and compare with cruise observations. The comparisons show that the model results in similar averaged magnitudes of iron solubility as measured during 8 cruises in 2001–2003. Comparisons show that results of cases including cloud, SO2 and hematite processing are better than the other approaches used using …

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Intrinsic Conformational Preferences Of Substituted Cyclohexanes And Tetrahydropyrans Evaluated At The Ccsd(T) Complete Basis Set Limit: Implications For The Anomeric Effect, Abby Jones Weldon, Trisha L. Vickrey, Gregory S. Tschumper Dec 2005

Intrinsic Conformational Preferences Of Substituted Cyclohexanes And Tetrahydropyrans Evaluated At The Ccsd(T) Complete Basis Set Limit: Implications For The Anomeric Effect, Abby Jones Weldon, Trisha L. Vickrey, Gregory S. Tschumper

Chemistry Faculty Research & Creative Works

A series of MP2 and CCSD(T) computations have been carried out with correlation consistent basis sets as large as aug-cc-pV5Z to determine the intrinsic equatorial-axial conformational preference of CH 3-, F-, OCH 3-, and OH-substituted cyclohexane and tetrahydropyran rings. The high-accuracy relative electronic energies reported here shed new light on the intrinsic energetics of these cyclic prototypes for the anomeric effect. At the CCSD(T) complete basis set (CBS) limit, the energy of the equatorial conformation relative to the axial position (ΔE CCSD(T)CBC) is -0.75, -0.20, -0.21, and -0.56 kcal mol -1 in methyl-, fluoro-, methoxy-, and hydroxy cyclohexane, respectively, while …

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Empirical Likelihood Inference For The Area Under The Roc Curve, Gengsheng Qin, Xiao-Hua Zhou Dec 2005

Empirical Likelihood Inference For The Area Under The Roc Curve, Gengsheng Qin, Xiao-Hua Zhou

UW Biostatistics Working Paper Series

For a continuous-scale diagnostic test, the most commonly used summary index of the receiver operating characteristic (ROC) curve is the area under the curve (AUC) that measures the accuracy of the diagnostic test. In this paper we propose an empirical likelihood approach for the inference of AUC. We first define an empirical likelihood ratio for AUC and show that its limiting distribution is a scaled chi-square distribution. We then obtain an empirical likelihood based confidence interval for AUC using the scaled chi-square distribution. This empirical likelihood inference for AUC can be extended to stratified samples and the resulting limiting distribution …

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