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2001

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Articles 241 - 270 of 2764

Full-Text Articles in Physical Sciences and Mathematics

Profile Combinatorics For Fragment Selection In Comparative Protein Structure Modeling, Deacon Sweeney, Travis E. Doom, Michael L. Raymer Nov 2001

Profile Combinatorics For Fragment Selection In Comparative Protein Structure Modeling, Deacon Sweeney, Travis E. Doom, Michael L. Raymer

Kno.e.sis Publications

Sequencing of the human genome was a great stride towards modeling cellular complexes, massive systems whose key players are proteins and DNA. A major bottleneck limiting the modeling process is structure and function annotation for the new genes. Contemporary protein structure prediction algorithms represent the sequence of every protein of known structure with a profile to which the profile of a protein sequence of unknown structure is compared for recognition. We propose a novel approach to increase the scope and resolution of protein structure profiles. Our technique locates equivalent regions among the members of a structurally similar fold family, and …


Hubble Space Telescope Wfpc2 Imaging Of Cassiopeia A, R. A. Fesen, J. A. Morse, R. A. Chevalier, K. J. Borkowski, C. L. Gerardy Nov 2001

Hubble Space Telescope Wfpc2 Imaging Of Cassiopeia A, R. A. Fesen, J. A. Morse, R. A. Chevalier, K. J. Borkowski, C. L. Gerardy

Dartmouth Scholarship

The young galactic supernova remnant Cassiopeia A was imaged with Wide Field Planetary Camera 2 (WFPC2) aboard the Hubble Space Telescope through filters selected to capture the complete velocity range of the remnant's main shell in several emission lines. The primary lines detected, along with the specific WFPC2 filters used, were [O III] λλ4959, 5007 (F450W), [N II] λ6583 (F658N), [S II] λλ6716, 6731 + [O II] λλ7319, 7330 + [O I] λλ6300, 6364 (F675W), and [S III] λλ9069, 9532 (F850LP). About three-quarters of the remnant's 4' diameter main shell was imaged with all four filters in three WFPC2 pointings, …


Comparison Of Stellar Angular Diameters From The Npoi, The Mark Iii Optical Interferometer, And The Infrared Flux Method, Tyler E. Nordgren, Jeffrey J. Sudol, D. Mozurkewich Nov 2001

Comparison Of Stellar Angular Diameters From The Npoi, The Mark Iii Optical Interferometer, And The Infrared Flux Method, Tyler E. Nordgren, Jeffrey J. Sudol, D. Mozurkewich

Physics & Engineering Faculty Publications

No abstract provided.


Concentration Gradient, Diffusion, And Flow Through Open Porous Medium Near Percolation Threshold Via Computer Simulations, Ras B. Pandey, J.F. Gettrust, D. Stauffer Nov 2001

Concentration Gradient, Diffusion, And Flow Through Open Porous Medium Near Percolation Threshold Via Computer Simulations, Ras B. Pandey, J.F. Gettrust, D. Stauffer

Faculty Publications

The interacting lattice gas model is used to simulate fluid flow through an open percolating porous medium with the fluid entering at the source-end and leaving from the opposite end. The shape of the steady-state concentration profile and therefore the gradient field depends on the porosity (p). The root mean square (rms) displacements of fluid and its constituents (tracers) show a drift power-law behavior, R∝t in the asymptotic regime (t→∞). The flux current density (j) is found to scale with the porosity according to, j∝(Δp)β with Δp …


A Dipolar Coupling Based Strategy For Simultaneous Resonance Assignment And Structure Determination Of Protein Backbones, Fang Tian, Homayoun Valafar, James H. Prestegard Nov 2001

A Dipolar Coupling Based Strategy For Simultaneous Resonance Assignment And Structure Determination Of Protein Backbones, Fang Tian, Homayoun Valafar, James H. Prestegard

Faculty Publications

A new approach for simultaneous protein backbone resonance assignment and structure determination by NMR is introduced. This approach relies on recent advances in high-resolution NMR spectroscopy that allow observation of anisotropic interactions, such as dipolar couplings, from proteins partially aligned in field ordered media. Residual dipolar couplings are used for both geometric information and a filter in the assembly of residues in a sequential manner. Experimental data were collected in less than one week on a small redox protein, rubredoxin, that was 15N enriched but not enriched above 1% natural abundance in 13C. Given the acceleration possible with partial 13C …


Micromagnetics Simulation Of Deep-Submicron Supermalloy Disks, Scott Whittenburg Nov 2001

Micromagnetics Simulation Of Deep-Submicron Supermalloy Disks, Scott Whittenburg

Chemistry Faculty Publications

The results of recent micromagnetic simulations of deep submicron supermalloy disks are presented. A recent experimental measurement of the hysteresis and magnetic domain structure in supermalloy disks with diameters ranging from 55 to 500 nm and thickness ranging from 6 to 15 nm has been reported. Our micromagnetic simulations show remarkable agreement with the experimental hysteresis loops. The simulation results show that for thin or small diameter disks a single magnetic domain exists with all spins aligned. The hysteresis loop represents free rotation of these spins. For larger diameter disks or as the thickness increases the hysteresis loops change shape …


Groundwater Study Of The Perenjori Townsite, Russell John Speed Nov 2001

Groundwater Study Of The Perenjori Townsite, Russell John Speed

Resource management technical reports

A groundwater study of the townsite of Perenjori. It aimed to accelerate the implementation of effective salinity management options. The study consisted of drilling investation and installation of a piezometer network, a pumping test, groundwater flow modelling and a flood risk analysis.


Inside Unlv, Betty Blodgett, Tom Flagg, Diane Russell Nov 2001

Inside Unlv, Betty Blodgett, Tom Flagg, Diane Russell

Inside UNLV

No abstract provided.


A Round Trip Time And Timeout Aware Traffic Conditioner For Differentiated Services Networks, Ahsan Habib, Bharat Bhargava, Sonia Fahmy Nov 2001

A Round Trip Time And Timeout Aware Traffic Conditioner For Differentiated Services Networks, Ahsan Habib, Bharat Bhargava, Sonia Fahmy

Department of Computer Science Technical Reports

No abstract provided.


Parameter Synthesis Of Higher Kinematic Planars, Min-Ho Kyung, Elisha Sacks Nov 2001

Parameter Synthesis Of Higher Kinematic Planars, Min-Ho Kyung, Elisha Sacks

Department of Computer Science Technical Reports

No abstract provided.


Using Ssm Proxies To Provide Efficient Multiple-Source Multicast Delivery, Daniel Zappala, Aaron Fabbri Nov 2001

Using Ssm Proxies To Provide Efficient Multiple-Source Multicast Delivery, Daniel Zappala, Aaron Fabbri

Faculty Publications

We consider the possibility that single-source multicast (SSM) will become a universal multicast service, enabling large-scale distribution of content from a few well-known sources to a general audience. Operating under this assumption, we explore the problem of building the traditional IP model of any-source multicast on top of SSM. Toward this end, we design an SSM proxy service that allows any sender to efficiently deliver content to a multicast group. We demonstrate the performance improvements this service offers over standard SSM and describe extensions for access control, dynamic proxy discovery, and multicast proxy distribution.


The Role Of Small And Medium Enterprises In The Economy Of Slovakia, Jaroslav Kling Nov 2001

The Role Of Small And Medium Enterprises In The Economy Of Slovakia, Jaroslav Kling

Student Work

The aim of this paper is to analyze the role of small and medium enterprises in the economy of Slovakia. The changes of 1989 brought about the changes of society and economy as well. In the period of transformation of the Slovak economy, small and medium enterprises have been often considered to be a critical element of economic revival. The study answers to what extent this expectation has been met. Legal and institutional frameworks of the small and medium enterprises development are analyzed. Popular attitudes toward entrepreneurs, views and opinions of the key representatives of entrepreneurs and state representatives are …


Ecdis Development Laboratory And Navigation Technology Demonstration Center, Lee Alexander, Maxim F. Van Norden, Charles M. Fralick Nov 2001

Ecdis Development Laboratory And Navigation Technology Demonstration Center, Lee Alexander, Maxim F. Van Norden, Charles M. Fralick

Center for Coastal and Ocean Mapping

The U.S. Navy is undergoing a major transition from traditional, paper chart navigation to computer-based electronic charting. The Chief of Naval Operations (CNO) has mandated that all Navy ships will navigate strictly through electronic means by FY07. However, due to some recent groundings, the Navy is now striving to accelerate the full implementation of electronic navigation by FY04. The Naval Oceanographic Office (NAVOCEANO) is making a concerted effort to support this transition with upgrades to state-of-the-art survey ships, instrumentation, and data processing equipment. NAVOCEANO is increasing its capability to rapidly collect and process hydrographic survey data, and to quickly produce …


Geozui3d: Data Fusion For Interpreting Oceanographic Data, Colin Ware, Matthew D. Plumlee, Roland J. Arsenault, Larry A. Mayer, Shep M. Smith Lt, Donald H. House Nov 2001

Geozui3d: Data Fusion For Interpreting Oceanographic Data, Colin Ware, Matthew D. Plumlee, Roland J. Arsenault, Larry A. Mayer, Shep M. Smith Lt, Donald H. House

Center for Coastal and Ocean Mapping

GeoZui3D stands for Geographic Zooming User Interface. It is a new visualization software system designed for interpreting multiple sources of 3D data. The system supports gridded terrain models, triangular meshes, curtain plots, and a number of other display objects. A novel center of workspace interaction method unifies a number of aspects of the interface. It creates a simple viewpoint control method, it helps link multiple views, and is ideal for stereoscopic viewing. GeoZui3D has a number of features to support real-time input. Through a CORBA interface external entities can influence the position and state of objects in the display. Extra …


Hypsometry And Volume Of The Arctic Ocean And Its Constituent's Seas, Martin Jakobsson Nov 2001

Hypsometry And Volume Of The Arctic Ocean And Its Constituent's Seas, Martin Jakobsson

Center for Coastal and Ocean Mapping

No abstract provided.


Electron-Impact Excitation To The 4p⁵5s And 4p⁵5p Levels Of Kr | Using Different Distorted-Wave And Close-Coupling Methods, Arati K. Dasgupta, Klaus Bartschat, D. Vaid, Alexei N. Grum-Grzhimailo, Don H. Madison, Milan Blaha, John L. Giuliani Nov 2001

Electron-Impact Excitation To The 4p⁵5s And 4p⁵5p Levels Of Kr | Using Different Distorted-Wave And Close-Coupling Methods, Arati K. Dasgupta, Klaus Bartschat, D. Vaid, Alexei N. Grum-Grzhimailo, Don H. Madison, Milan Blaha, John L. Giuliani

Physics Faculty Research & Creative Works

Electron-impact excitation of the 4p55s and 4p55p levels of Kr I has been investigated in detail by calculating cross sections using distorted-wave and close-coupling approaches. The results are presented from the excitation thresholds up to 50 eV incident energy. They are contrasted among the different calculations and compared with other theoretical predictions and experimental data. Significant disagreement is found with many of the recent experimental data of Chilton et al. [Phys. Rev. A 62, 032714 (2000)].


Three-Body Coulomb Problem Probed By Mapping The Bethe Surface In Ionizing Ion-Atom Collisions, Robert Moshammer, Appathurai N. Perumal, Michael Schulz, V. D. Rodriguez, Holger Kollmus, Rido Mann, Siegbert Hagmann, Joachim Hermann Ullrich Nov 2001

Three-Body Coulomb Problem Probed By Mapping The Bethe Surface In Ionizing Ion-Atom Collisions, Robert Moshammer, Appathurai N. Perumal, Michael Schulz, V. D. Rodriguez, Holger Kollmus, Rido Mann, Siegbert Hagmann, Joachim Hermann Ullrich

Physics Faculty Research & Creative Works

The three-body Coulomb problem has been explored in kinematically complete experiments on single ionization of helium by 100 MeV / u C 6 + and 3.6 MeV / u u 5 3 + impact. Low-energy electron emission (E e < 150 eV ) as a function of the projectile deflection ϑ p (momentum transfer), i.e., the Bethe surface [[15]], has been mapped with Δ ϑ p ± 25 nanoradian resolution at extremely large perturbations (3.6 MeV / uAu53+ ) where single ionization occurs at impact parameters of typically 10 times the He K -shell radius. The experimental data are not in agreement with state-of-the-art continuum distorted wave-eikonal initial state theory.


Multiwavelength Monitoring Of The Narrow-Line Seyfert 1 Galaxy Arakelian 564. Iii. Optical Observations And The Optical--Uv--X-Ray Connection, O. Shemmer, P. Romano, R. Bertram, W. Brinkmann, S. Collier, K. A. Crowley, E. Detsis, A. V. Filippenko, C. Martin Gaskell, T. A. George, M. Gliozzi, M. E. Hiller, T. L. Jewell, Shai Kaspi, Elizabeth S. Klimek, M. H. Lannon, W D. Li, P. Martini, Smita Mathur, H. Negoro, Hagai Netzer, Iossif Papadakis, Ioannis Papamastorakis, Bradley M. Peterson, Bradley W. Peterson, Richard William Pogge, V. I. Pronik, Kenneth S. Rumstay, S. G. Sergeev, G. M. Stirpe, C. J. Taylor, R. R. Treffers, T. J. Turner, P. Uttley, Marianne Vestergaard, Kaspar Von Braun, R. M. Wagner, Z. Zheng Nov 2001

Multiwavelength Monitoring Of The Narrow-Line Seyfert 1 Galaxy Arakelian 564. Iii. Optical Observations And The Optical--Uv--X-Ray Connection, O. Shemmer, P. Romano, R. Bertram, W. Brinkmann, S. Collier, K. A. Crowley, E. Detsis, A. V. Filippenko, C. Martin Gaskell, T. A. George, M. Gliozzi, M. E. Hiller, T. L. Jewell, Shai Kaspi, Elizabeth S. Klimek, M. H. Lannon, W D. Li, P. Martini, Smita Mathur, H. Negoro, Hagai Netzer, Iossif Papadakis, Ioannis Papamastorakis, Bradley M. Peterson, Bradley W. Peterson, Richard William Pogge, V. I. Pronik, Kenneth S. Rumstay, S. G. Sergeev, G. M. Stirpe, C. J. Taylor, R. R. Treffers, T. J. Turner, P. Uttley, Marianne Vestergaard, Kaspar Von Braun, R. M. Wagner, Z. Zheng

Department of Physics and Astronomy: Faculty Publications

We present the results of a 2 yr long optical monitoring program of the narrow-line Seyfert 1 galaxy Ark 564. The majority of this monitoring project was also covered by X-ray observations (RXT E), and for a period of ~50 days, we observed the galaxy in UV (HST) and X-rays (RXTE and ASCA) simultaneously with the ground-based observations. Rapid and large-amplitude variations seen in the X-ray band, on a daily and hourly timescale, were not detected at optical and UV wavelengths, which in turn exhibited much lower variability either on short (1 day) or long (several months) timescales. The only …


Privacy Protection For Transactions Of Digital Goods, Feng Bao, Robert H. Deng Nov 2001

Privacy Protection For Transactions Of Digital Goods, Feng Bao, Robert H. Deng

Research Collection School Of Computing and Information Systems

In this paper we study the problem of how to protect users’ privacy in web transactions of digital goods. In particular, we introduce a system which allows a user to disclose his/her identity information (such as user account or credit card number) to a web site in exchange for a digital item, but prevents the web site from learning which specific item the user intends to obtain. The problem concerned here is orthogonal to the problem of anonymous transactions [RSG98], [RR98] but commensurate with the general problem of PIR (private information retrieval) [CGK95]


Capillary Flow In Interior Corners: The Infinite Column, Mark M. Weislogel Nov 2001

Capillary Flow In Interior Corners: The Infinite Column, Mark M. Weislogel

Mechanical and Materials Engineering Faculty Publications and Presentations

Capillary flow of a sinusoidally perturbed liquid column in an interior corner of infinite extent is solved using lubrication theory. Due primarily to the length scales selected to nondimensionalize the momentum equation, an analytic time scale governing the settling of the perturbation is determined. The time scale, which is shown to be independent of a steady base state flow, proves useful in rapidly predicting transients for surface settling in certain liquid-bearing tanks of spacecraft employing interior corners for fluids management purposes. The asymptotic analysis is extended to address flows along interior corners whose faces are slightly nonplanar. The generalized formulation …


Hierarchical Text Classification And Evaluation, Aixin Sun, Ee Peng Lim Nov 2001

Hierarchical Text Classification And Evaluation, Aixin Sun, Ee Peng Lim

Research Collection School Of Computing and Information Systems

Hierarchical Classification refers to assigning of one or more suitable categories from a hierarchical category space to a document. While previous work in hierarchical classification focused on virtual category trees where documents are assigned only to the leaf categories, we propose atop-down level-based classification method that can classify documents to both leaf and internal categories. As the standard performance measures assume independence between categories, they have not considered the documents incorrectly classified into categories that are similar or not far from the correct ones in the category tree. We therefore propose the Category-Similarity Measures and Distance-Based Measures to consider the …


Pickup And Delivery Problem With Time Windows: Algorithms And Test Case Generation, Hoong Chuin Lau, Zhe Liang Nov 2001

Pickup And Delivery Problem With Time Windows: Algorithms And Test Case Generation, Hoong Chuin Lau, Zhe Liang

Research Collection School Of Computing and Information Systems

In the pickup and delivery problem with time windows (PDPTW), vehicles have to transport loads from origins to destinations respecting capacity and time constraints. In this paper, we present a two-phase method to solve the PDPTW. In the first phase, we apply a novel construction heuristics to generate an initial solution. In the second phase, a tabu search method is proposed to improve the solution. Another contribution of this paper is a strategy to generate good problem instances and benchmarking solutions for PDPTW, based on Solomon's benchmark test cases for VRPTW. Experimental results show that our approach yields very good …


Genetic And Environmental Risk Factors Associated With Colon Cancer, Shamma Rashed Khalfan Al-Naili Al-Shamsi Nov 2001

Genetic And Environmental Risk Factors Associated With Colon Cancer, Shamma Rashed Khalfan Al-Naili Al-Shamsi

Theses

Colorectal cancer represents one of the most common causes of mortality in the world. A major number of populations develop an adenoma by the age of 40s. Over the past years, it has become clear that genetic factors are of crucial importance in colorectal tumorigenesis. Familial adenomatous polyposis (FAP) is responsible of developing numerous colorectal cancers cases by causing mutations in the germline in adenomatous polyposis coli (APC) genes.

Colon cancer is considered the second most frequent cause of death in most of the Western countries. Colonic cancer is common in women and rectal in men. It arise in adenomatous …


Seismicity In The Vicinity Of Yucca Mountain, Nevada, For The Period October 1, 1999 To September 30, 2000, David H. Von Seggern, Ken Smith, James N. Brune, Richard Quittmeyer, Amy J. Smiecinski Oct 2001

Seismicity In The Vicinity Of Yucca Mountain, Nevada, For The Period October 1, 1999 To September 30, 2000, David H. Von Seggern, Ken Smith, James N. Brune, Richard Quittmeyer, Amy J. Smiecinski

Publications (YM)

Starting on October 1, 1995, the monitoring of seismicity within the southern Great Basin near Yucca Mountain was performed with a new digital network. This network features three-component recording with 24-bit A/D conversion in the field. Continuous data are collected at 20 sps, and event triggered windows are collected at 100 sps. A seismic bulletin of events is made by automatically associating triggers among stations, classifying the local earthquake events, and locating the earthquakes and computing their magnitudes with conventional methods. This report covers the operational and seismic results of the fifth full year (FYOO) of the improved, digitally based, …


Complementary Ansatz For The Neutrino Mass Matrix, Joseph Schechter, Deirdre Black, Amir H. Fariborz, Salah Nasri Oct 2001

Complementary Ansatz For The Neutrino Mass Matrix, Joseph Schechter, Deirdre Black, Amir H. Fariborz, Salah Nasri

Physics - All Scholarship

We propose a simple Ansatz for the three generation neutrino mass matrix M_\nu which is motivated from an SO(10) grand unified theory. The Ansatz can be combined with information from neutrino oscillation experiments and bounds on neutrinoless double beta decay to determine the neutrino masses themselves and to reconstruct, with some assumptions, the matrix M_\nu.


Strike One, You're Out: Airports, Aircraft, Safety & Wildlife, Bette Blinde Oct 2001

Strike One, You're Out: Airports, Aircraft, Safety & Wildlife, Bette Blinde

Other Bird Strike and Aviation Materials

This activity is part of a program that asks students to use their problem-solving abilities to evaluate, plan and design a solution to real life dilemmas. This dilemma focuses on airports, aircraft, safety and wildlife. It is one of a series of dilemmas that allows students to learn about natural resource and environmental issues by developing solutions to complex and actual problems being faced.


Modeling Axisymmetric Optical Precision Piezoelectric Membranes, James W. Rogers Jr. Oct 2001

Modeling Axisymmetric Optical Precision Piezoelectric Membranes, James W. Rogers Jr.

Theses and Dissertations

The US Department of Defense (DOD), as well as the National Aeronautics and Astronautics Administration (NASA) and the Jet Propulsion Laboratory (JPL) are interested in developing and deploying precise, compliant, light-weight, space-based structures. More specifically, the Air Force’s core competencies ‘Aerospace Superiority’ and ‘Information Superiority’ demand ever-increasing depth and breadth of capability. Whether used for energy transmission or optical reconnaissance, current launch restraints limit rigid space-based optical reflector size. To support this requirement, the Air Force Research Laboratory (AFRL) is developing a large space-based optical membrane telescope. Inflatable reflectors can conceptually break this barrier, but controlling such a compliant structure …


Assessment Of Criticality Safety For Cylindrical Containers To Be Used In The Processing Of Spent Fuel, William Culbreth, Daniel R. Lowe, Jason Viggato Oct 2001

Assessment Of Criticality Safety For Cylindrical Containers To Be Used In The Processing Of Spent Fuel, William Culbreth, Daniel R. Lowe, Jason Viggato

Separations Campaign (TRP)

The UREX process separates uranium from transuranic wastes (TRU) and fission products (FP). Nuclear reactors require fissile isotopes that will absorb neutrons and break apart into smaller nuclei while releasing a large amount of energy as well as multiple neutrons. Fissile isotopes in spent fuel include not only 235U, but also 239Pu, 241Pu, and several isotopes of americium (Am) and curium (Cm).

TRU contains the actinides with atomic numbers greater than that of uranium. This includes Pu, Np, Am, and Cm. When TRU is separated from uranium, the TRU still poses a significant risk of sustaining a …


An Improved Method For Determining Snowmelt Onset Dates Over Arctic Sea Ice Using Scanning Multichannel Microwave Radiometer And Special Sensor Microwave/Imager Data, Sheldon D. Drobot, Mark R. Anderson Oct 2001

An Improved Method For Determining Snowmelt Onset Dates Over Arctic Sea Ice Using Scanning Multichannel Microwave Radiometer And Special Sensor Microwave/Imager Data, Sheldon D. Drobot, Mark R. Anderson

Department of Earth and Atmospheric Sciences: Faculty Publications

Ablation of snow over sea ice is an important physical process affecting the Arctic surface energy balance. An improved understanding of the spatial and temporal variations in snowmelt onset could be utilized to improve climate simulations in the Arctic, as well as monitor the Arctic for signs of climate change. Utilizing an updated approach for monitoring snowmelt onset over Arctic sea ice, spatial variability in passive microwave derived snowmelt onset dates is examined from 1979 through 1998. The improved technique, termed the advanced horizontal range algorithm (AHRA), utilizes temporal variations in 18/19G Hz and 37 GHz passive microwave horizontal brightness …


Investigating The Light Scalar Mesons, Joseph Schechter, D. Black, Amir H. Fariborz, Salah Moussa, S. Nasri Oct 2001

Investigating The Light Scalar Mesons, Joseph Schechter, D. Black, Amir H. Fariborz, Salah Moussa, S. Nasri

Physics - All Scholarship

We first briefly review a treatment of the scalars in meson meson scattering based on a non-linear chiral Lagrangian, with unitarity implemented by a "local" modification of the scalar propagators. It is shown that the main results are confirmed by a treatment in the SU(3) linear sigma model in which unitarity is implemented "globally". Some remarks are made on the speculative subject of the scalars' quark structure.