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2007

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Articles 1 - 30 of 6538

Full-Text Articles in Physical Sciences and Mathematics

Biological, Clinical, And Forensic Analysis Using Comprehensive Two-Dimensional Gas Chromatography, Nicholas Snow Jun 2015

Biological, Clinical, And Forensic Analysis Using Comprehensive Two-Dimensional Gas Chromatography, Nicholas Snow

Nicholas A Snow

No abstract provided.


Distribution And Transport Of Coal Tar-Derived Pahs In Fine-Grained Residuum, Vijay Vulava, Larry Mckay, Steven Driese, Fu-Min Menn, Gary Sayler Jun 2013

Distribution And Transport Of Coal Tar-Derived Pahs In Fine-Grained Residuum, Vijay Vulava, Larry Mckay, Steven Driese, Fu-Min Menn, Gary Sayler

Gary S. Sayler

We investigated the distribution and transport of coal tar-derived polycyclic aromatic hydrocarbons (PAHs) in fine-grained residuum and alluvial floodplain deposits that underlie a former manufactured gas plant. All 16 USEPA priority pollutant PAHs are present at this site and have penetrated the entire 4–5 m thickness of clayey sediments, which unconformably overly limestone bedrock. Concentrations of less hydrophobic PAHs (e.g., naphthalene, 0.011–384 mg kg−1) were about 10 times higher than those of highly hydrophobic PAHs (e.g., benzo[g, h, i]perylene −0.002 to 56.03 mg kg−1). Microscopic examination of thin-sections of ...


Humancentric Applications Of Rfid Chips, S. Derrick, K. Michael, H. Tootell Dec 2012

Humancentric Applications Of Rfid Chips, S. Derrick, K. Michael, H. Tootell

Dr Holly Tootell

No abstract provided.


Metal Modulation Epitaxy Growth For Extremely High Hole Concentrations Above 10(19) Cm(-3) In Gan, Gon Namkoong, Elaissa Trybus, Kyung Keun Lee, Michael Moseley, W. Alan Doolittle, David C. Look Dec 2007

Metal Modulation Epitaxy Growth For Extremely High Hole Concentrations Above 10(19) Cm(-3) In Gan, Gon Namkoong, Elaissa Trybus, Kyung Keun Lee, Michael Moseley, W. Alan Doolittle, David C. Look

Applied Research Center Publications

The free hole carriers in GaN have been limited to concentrations in the low 1018 cm−3 range due to the deep activation energy, lower solubility, and compensation from defects, therefore, limiting doping efficiency to about 1%. Herein, we report an enhanced doping efficiency up to ~10% in GaN by a periodic doping, metal modulation epitaxy growth technique. The hole concentrations grown by periodically modulating Ga atoms and Mg dopants were over ~1.5 x 1019 cm−3.

© 2008 American Institute of Physics.


Unit Rectangle Visibility Graphs, Alice M. Dean, Joanna A. Ellis-Monaghan, Sarah J. Hamilton, Greta Pangborn Dec 2007

Unit Rectangle Visibility Graphs, Alice M. Dean, Joanna A. Ellis-Monaghan, Sarah J. Hamilton, Greta Pangborn

Mathematics, Statistics and Computer Science Faculty Research and Publications

Over the past twenty years, rectangle visibility graphs have generated consider- able interest, in part due to their applicability to VLSI chip design. Here we study unit rectangle visibility graphs, with fixed dimension restrictions more closely modeling the constrained dimensions of gates and other circuit components in computer chip applications. A graph G is a unit rectangle visibility graph (URVG) if its vertices can be represented by closed unit squares in the plane with sides parallel to the axes and pairwise disjoint interiors, in such a way that two vertices are adjacent if and only if there is a non-degenerate ...


Muon-Fluorine Entangled States In Molecular Magnets, T Lancaster, S J. Blundell, P J. Baker, M L. Brooks, W Hayes, F L. Pratt, Jamie L. Manson, M M. Conner, J A. Schlueter Dec 2007

Muon-Fluorine Entangled States In Molecular Magnets, T Lancaster, S J. Blundell, P J. Baker, M L. Brooks, W Hayes, F L. Pratt, Jamie L. Manson, M M. Conner, J A. Schlueter

Chemistry and Biochemistry Faculty Publications

The information accessible from a muon-spin relaxation experiment can be limited due to a lack of knowledge of the precise muon stopping site. We demonstrate here the possibility of localizing a spin polarized muon in a known stopping state in a molecular material containing fluorine. The muon-spin precession that results from the entangled nature of the muon spin and surrounding nuclear spins is sensitive to the nature of the stopping site. We use this property to identify three classes of sites that occur in molecular magnets and describe the extent to which the muon distorts its surroundings.


Back Matter Dec 2007

Back Matter

Journal of Digital Forensics, Security and Law

No abstract provided.


Interagency Science And Research: Quarterly Progress Report, Period Ending December 31, 2007, Margaret N. Rees Dec 2007

Interagency Science And Research: Quarterly Progress Report, Period Ending December 31, 2007, Margaret N. Rees

Interagency Science and Research Strategy

  • Meetings were held with the SNAP Recreation Team and the SNAP Cultural Resources Team to request assistance in the development of the science strategy. Draft versions of interagency goals, subgoals, science questions, and associated tasks were given to each team for review and input.
  • Plans were prepared for the peer review of science proposals submitted for consideration as Conservations Initiatives in SNPLMA Round 9.
  • Proceedings of the natural resources management workshop held on September 13 were completed and sent to the Science & Research Team for review by members.
  • An important focus of the Science and Research Team was the development ...


Limnological Assistance For The Lake Mead National Recreation Area In Meeting The Challenge Of The Water 2025 Initiative: Quarterly Progress Report, Period Ending: December 1, 2007, Margaret N. Rees Dec 2007

Limnological Assistance For The Lake Mead National Recreation Area In Meeting The Challenge Of The Water 2025 Initiative: Quarterly Progress Report, Period Ending: December 1, 2007, Margaret N. Rees

Limnological Studies

  • The limnologist position has been announced.
  • Project 1: Review of the draft Boulder Basin Adaptive Management Plan is underway.
  • Project 2: Development of a white paper expressing the joint needs of the entities involved in Water 2025 projects is being coordinated.
  • Project 3: A bibliographic reference spreadsheet organizing literature citations related to quagga and zebra mussel research has been completed.
  • Project 4: A comprehensive literature search of Lake Mead limnology is well underway; an Access database has been designed to organize reference citations; and a special collections library at UNLV is being established to house original rare documents and other ...


Lake Mead National Recreation Area Vegetation Monitoring And Management: Quarterly Progress Report, October 1, 2007 To December 31, 2007, Margaret N. Rees Dec 2007

Lake Mead National Recreation Area Vegetation Monitoring And Management: Quarterly Progress Report, October 1, 2007 To December 31, 2007, Margaret N. Rees

Vegetation Monitoring

Executive Summary

  • The Weed Sentry program surveyed more than 750 miles of federal lands in Clark County for invasive, exotic plant species.
  • Weed Sentry also removed more than 600,000 individual invasive plants from federal
    lands. These removals represent pro-active efforts that may have forestalled large
    infestations difficult and costly to eradicate.
  • In response to a request by the manager of the Fish and Wildlife Service Desert National
    Wildlife Refuge, a major effort of surveying springs for plant community composition
    and invasive plants provided unique knowledge services by the Weed Sentry program.
    No such baseline information existed for the Sheep ...


Lake Mead National Recreation Area Sensitive Wildlife Species Monitoring And Analysis: Quarterly Progress Report, Period Ending December 31, 2007, Margaret N. Rees Dec 2007

Lake Mead National Recreation Area Sensitive Wildlife Species Monitoring And Analysis: Quarterly Progress Report, Period Ending December 31, 2007, Margaret N. Rees

Wildlife Monitoring

Project 1. Relict Leopard Frog Monitoring, Management, and Research

  • Fall surveys completed at all natural and translocation sites.
  • Coordination for a potential translocation site on BLM lands in the Gold Butte area ongoing – the aim is that this site will be ready for translocations in 2008.
  • Coordination ongoing for evaluation of a translocation site on BLM lands in the Black Mountains, AZ – the plan is to complete compliance in 2008.
  • Coordination and assistance provided to UNLV research efforts on habitat improvements at Blue Point, Rogers, and Pupfish Refuge springs.
  • Relict Leopard Frog Conservation Team meeting held in December.
  • Draft annual ...


Nevada Interagency Volunteer Program: Helping Hands Across Public Lands – Phase Ii: Quarterly Progress Report, Period Covering October 1 – December 31, 2007, Margaret N. Rees Dec 2007

Nevada Interagency Volunteer Program: Helping Hands Across Public Lands – Phase Ii: Quarterly Progress Report, Period Covering October 1 – December 31, 2007, Margaret N. Rees

Get Outdoors Nevada

  • The number of records in the volunteer database increased 12% over last quarter. The database now contains 4,937 records.
  • Website activity decreased, recording an average of 82,859 hits per month, a decrease of 31% from last quarter, with an average of 8,191 pages viewed per month.
  • Volunteer fall training has been completed.
  • Three National Public Land Day Events have been completed.
  • Two hundred and ten people attended the Volunteer Recognition Event.


Masthead Dec 2007

Masthead

Journal of Digital Forensics, Security and Law

No abstract provided.


Front Matter Dec 2007

Front Matter

Journal of Digital Forensics, Security and Law

No abstract provided.


Casimir Effect In Quantum Physics, Matthew James Urfer Dec 2007

Casimir Effect In Quantum Physics, Matthew James Urfer

Masters Theses

No abstract provided.


Numerical Approximations Of Differential Equations And Applications In Maple, Joyce Zimmerman Dec 2007

Numerical Approximations Of Differential Equations And Applications In Maple, Joyce Zimmerman

Masters Theses

No abstract provided.


Unresolved Issues With The Assessment Of Multidecadal Global Land Surface Temperature Trends, Roger A. Pielke Sr., Christopher A. Davey, Dev Niyogi, Souleymane Fall, Jesse Steinweg-Woods, Ken Hubbard, Xiaomao Lin, Ming Cai, Young-Kwon Lim, Hong Li, John Nielsen-Gammon, Kevin Gallo, Robert Hale, Rezaul Mahmood, Stuart Foster, Richard T. Mcnider, Peter Blanken Dec 2007

Unresolved Issues With The Assessment Of Multidecadal Global Land Surface Temperature Trends, Roger A. Pielke Sr., Christopher A. Davey, Dev Niyogi, Souleymane Fall, Jesse Steinweg-Woods, Ken Hubbard, Xiaomao Lin, Ming Cai, Young-Kwon Lim, Hong Li, John Nielsen-Gammon, Kevin Gallo, Robert Hale, Rezaul Mahmood, Stuart Foster, Richard T. Mcnider, Peter Blanken

Papers in Natural Resources

This paper documents various unresolved issues in using surface temperature trends as a metric for assessing global and regional climate change. A series of examples ranging from errors caused by temperature measurements at a monitoring station to the undocumented biases in the regionally and globally averaged time series are provided. The issues are poorly understood or documented and relate to micrometeorological impacts due to warm bias in nighttime minimum temperatures, poor siting of the instrumentation, effect of winds as well as surface atmospheric water vapor content on temperature trends, the quantification of uncertainties in the homogenization of surface temperature data ...


Optical Estimation Of Auroral Ion Upflow: Theory, M. Zettergren, J. L. Semeter, P. L. Blelly, M. Diaz Dec 2007

Optical Estimation Of Auroral Ion Upflow: Theory, M. Zettergren, J. L. Semeter, P. L. Blelly, M. Diaz

Publications

This work presents a systematic analysis of optical emissions related to auroral ion upflow. Optical intensities and field‐aligned ion transport are computed for a set of monoenergetic incident electron beams using a combined fluid‐kinetic model. The kinetic portion models the energetic particle transport with a multiple stream approach and provides ionization, excitation, and heating rates to an eight‐moment fluid model of the ionosphere, which then calculates the resulting ion upflow. The analysis is used to develop a technique for estimating upward ion flux from photometric measurements at five discrete wavelengths: 427.8 nm, 557.7 nm, 630 ...


Theory And Numerics Of Gravitational Waves From Preheating After Inflation, Jean-François Dufaux, Amanda Bergman, Gary Felder, Lev Kofman, Jean-Philippe Uzan Dec 2007

Theory And Numerics Of Gravitational Waves From Preheating After Inflation, Jean-François Dufaux, Amanda Bergman, Gary Felder, Lev Kofman, Jean-Philippe Uzan

Physics: Faculty Publications

Preheating after inflation involves large, time-dependent field inhomogeneities, which act as a classical source of gravitational radiation. The resulting spectrum might be probed by direct detection experiments if inflation occurs at a low enough energy scale. In this paper, we develop a theory and algorithm to calculate, analytically and numerically, the spectrum of energy density in gravitational waves produced from an inhomogeneous background of stochastic scalar fields in an expanding universe. We derive some generic analytical results for the emission of gravity waves by stochastic media of random fields, which can test the validity/accuracy of numerical calculations. We contrast ...


Extending The Information Partition Function: Modeling Interaction Effects In Highly Multivariate, Discrete Data, Paul C. Cannon Dec 2007

Extending The Information Partition Function: Modeling Interaction Effects In Highly Multivariate, Discrete Data, Paul C. Cannon

Theses and Dissertations

Because of the huge amounts of data made available by the technology boom in the late twentieth century, new methods are required to turn data into usable information. Much of this data is categorical in nature, which makes estimation difficult in highly multivariate settings. In this thesis we review various multivariate statistical methods, discuss various statistical methods of natural language processing (NLP), and discuss a general class of models described by Erosheva (2002) called generalized mixed membership models. We then propose extensions of the information partition function (IPF) derived by Engler (2002), Oliphant (2003), and Tolley (2006) that will allow ...


Exploiting Self-Assembly For Ligand-Scaffold Optimization: Substrate-Tailored Ligands For Efficient Catalytic Asymmetric Hydroboration, Shin A. Moteki, James M. Takacs Dec 2007

Exploiting Self-Assembly For Ligand-Scaffold Optimization: Substrate-Tailored Ligands For Efficient Catalytic Asymmetric Hydroboration, Shin A. Moteki, James M. Takacs

James Takacs Publications

A self-assembled ligand library (SAL XY) affords a wide range of R/S ratios in Rh-catalyzed asymmetric hydroboration (nbd = 2,5norbornadiene, R* is a chiral substituent). Ligand-scaffold optimization reveals “substrate-tailored” ligands that afford high regio- and enantioselectivity for a variety of ortho-substituted styrene derivatives.

Includes article (4 pp.) and supporting information (106 pp.).


Validation Of The Aura Microwave Limb Sounder Hnomeasurements, M L. Santee, A Lambert, W G. Read, N J. Livesey, R E. Cofield, D T. Cuddy, W H. Daffer, B J. Drouin, L Froidevaux, R A. Fuller, R F. Jarnot, B W. Knosp, G L. Manney, V S. Perun, W V. Snyder, P C. Stek, R P. Thurstans, P A. Wagner, J W. Waters, G Muscari, R L. De Zafra, Jack E. Dibb, D W. Fahey, P J. Popp, T P. Marcy, K W. Jucks, G C. Toon, R A. Stachnik, P F. Bernath, C D. Boone, K A. Walker, J Urban, D Murtagh Dec 2007

Validation Of The Aura Microwave Limb Sounder Hnomeasurements, M L. Santee, A Lambert, W G. Read, N J. Livesey, R E. Cofield, D T. Cuddy, W H. Daffer, B J. Drouin, L Froidevaux, R A. Fuller, R F. Jarnot, B W. Knosp, G L. Manney, V S. Perun, W V. Snyder, P C. Stek, R P. Thurstans, P A. Wagner, J W. Waters, G Muscari, R L. De Zafra, Jack E. Dibb, D W. Fahey, P J. Popp, T P. Marcy, K W. Jucks, G C. Toon, R A. Stachnik, P F. Bernath, C D. Boone, K A. Walker, J Urban, D Murtagh

Earth Sciences Scholarship

We assess the quality of the version 2.2 (v2.2) HNO3 measurements from the Microwave Limb Sounder (MLS) on the Earth Observing System Aura satellite. The MLS HNO3 product has been greatly improved over that in the previous version (v1.5), with smoother profiles, much more realistic behavior at the lowest retrieval levels, and correction of a high bias caused by an error in one of the spectroscopy files used in v1.5 processing. The v2.2 HNO3 data are scientifically useful over the range 215 to 3.2 hPa, with single-profile precision of ∼0.7 ...


Flux, Gaugino Condensation, And Antibranes In Heteroic M Theory, James Gray, André Lukas, Burt A. Ovrut Dec 2007

Flux, Gaugino Condensation, And Antibranes In Heteroic M Theory, James Gray, André Lukas, Burt A. Ovrut

Department of Physics Papers

We present the potential energy due to flux and gaugino condensation in heterotic M theory compactifications with antibranes in the vacuum. For reasons which we explain in detail, the contributions to the potential due to flux are not modified from those in supersymmetric contexts. The discussion of gaugino condensation is, however, changed by the presence of antibranes. We show how a careful microscopic analysis of the system allows us to use standard results in supersymmetric gauge theory in describing such effects—despite the explicit supersymmetry breaking which is present. Not surprisingly, the significant effect of antibranes on the threshold corrections ...


Science Plan For Potential 2008 Experimental High Flow At Glen Canyon Dam, Grand Canyon Monitoring And Research Center Dec 2007

Science Plan For Potential 2008 Experimental High Flow At Glen Canyon Dam, Grand Canyon Monitoring And Research Center

All U.S. Government Documents (Utah Regional Depository)

No abstract provided.


Phase Dynamics Of Inas/Gaas Quantum Dot Semiconductor Optical Amplifiers, T. Piwonski, Guillaume Huyet, Et. Al. Dec 2007

Phase Dynamics Of Inas/Gaas Quantum Dot Semiconductor Optical Amplifiers, T. Piwonski, Guillaume Huyet, Et. Al.

Physical Sciences Publications

The gain and phase dynamics of InAs∕GaAs quantum dot amplifiers are studied using single and two-color heterodyne pump probe spectroscopy. The relaxation of the wetting layer carrier density is shown to have a strong effect on the phase dynamics of both ground and excited state transients, while having a much weaker effect on the gain dynamics. In addition, the dynamical alpha factor may also display a constant value after an initial transient. Such behavior is strongly encouraging for reduced pattern effect operation in high speed optical networks.


Model-Robust Bayesian Regression And The Sandwich Estimator, Adam A. Szpiro, Kenneth M. Rice, Thomas Lumley Dec 2007

Model-Robust Bayesian Regression And The Sandwich Estimator, Adam A. Szpiro, Kenneth M. Rice, Thomas Lumley

UW Biostatistics Working Paper Series

PLEASE NOTE THAT AN UPDATED VERSION OF THIS RESEARCH IS AVAILABLE AS WORKING PAPER 338 IN THE UNIVERSITY OF WASHINGTON BIOSTATISTICS WORKING PAPER SERIES (http://www.bepress.com/uwbiostat/paper338).

In applied regression problems there is often sufficient data for accurate estimation, but standard parametric models do not accurately describe the source of the data, so associated uncertainty estimates are not reliable. We describe a simple Bayesian approach to inference in linear regression that recovers least-squares point estimates while providing correct uncertainty bounds by explicitly recognizing that standard modeling assumptions need not be valid. Our model-robust development parallels frequentist estimating ...


Toward A New Generation Of Ice Sheet Models, Christopher M. Little, Michael Oppenheimer, Richard B. Alley, Venkatramani Balaji, Garry K. C. Clarke, Thomas L. Delworth, Robert Hallberg, David Holland, Christina L. Hulbe, Stan Jacobs, Jesse V. Johnson, Hiram Levy, William Lipscomb, Shawn J. Marshall, Byron R. Parizek, Antony J. Payne, Gavin A. Schmidt, Ronald J. Stouffer, David G. Vaughan, Michael Winton Dec 2007

Toward A New Generation Of Ice Sheet Models, Christopher M. Little, Michael Oppenheimer, Richard B. Alley, Venkatramani Balaji, Garry K. C. Clarke, Thomas L. Delworth, Robert Hallberg, David Holland, Christina L. Hulbe, Stan Jacobs, Jesse V. Johnson, Hiram Levy, William Lipscomb, Shawn J. Marshall, Byron R. Parizek, Antony J. Payne, Gavin A. Schmidt, Ronald J. Stouffer, David G. Vaughan, Michael Winton

Computer Science Faculty Publications

This report summarizes the conclusions and recommendations of a 1-day workshop on ice sheet modeling held at the NOAA Geophysical Fluid Dynamics Laboratory on 8 January 2007, sponsored by NOAA and by the Program in Science, Technology, and Environmental Policy of the Woodrow Wilson School of Public and International Affairs at Princeton University, N. J.


Imaging Thermal Stratigraphy In Freshwater Lakes Using Georadar, John H. Bradford, Cody R. Johnson, Troy Brosten, James P. Mcnamara, Michael N. Gooseff Dec 2007

Imaging Thermal Stratigraphy In Freshwater Lakes Using Georadar, John H. Bradford, Cody R. Johnson, Troy Brosten, James P. Mcnamara, Michael N. Gooseff

CGISS Publications and Presentations

Thermal stratification exerts significant control over biogeochemical processing in freshwater lakes. Thus, the temporal and spatial distribution of the thermal structure is an important component in understanding lake ecosystems. We present the first reported observations of lake thermal stratification from surface based georadar measurements acquired over two small freshwater lakes. This method is very useful because it can provide rapid acquisition of 2D or 3D lotic stratification.


An Explanation Of Srs Beam Cleanup In Graded-Index Fibers And The Absence Of Srs Beam Cleanup In Step-Index Fibers, Nathan B. Terry, Thomas G. Alley, Timothy H. Russell Dec 2007

An Explanation Of Srs Beam Cleanup In Graded-Index Fibers And The Absence Of Srs Beam Cleanup In Step-Index Fibers, Nathan B. Terry, Thomas G. Alley, Timothy H. Russell

Faculty Publications

Beam cleanup via stimulated Raman scattering in multimode fibers is modeled by numerically considering the competition between the Stokes modes of graded-index and step-index fibers. The relative gain of each Stokes mode is calculated by considering the overlap the various pump and Stokes modes of the fibers. Mode competition in a graded-index fiber favors the LP01 Stokes mode while mode competition in a step-index fiber does not favor the LP01 Stokes mode. This model explains why beam cleanup has only been reported for graded-index fibers and not for step-index fibers.


Tidal Asymmetry And Residual Circulation Over Linear Sandbanks And Their Implication On Sediment Transport: A Process-Oriented Numerical Study, Rosario Sanay, George Voulgaris, John C. Warner Dec 2007

Tidal Asymmetry And Residual Circulation Over Linear Sandbanks And Their Implication On Sediment Transport: A Process-Oriented Numerical Study, Rosario Sanay, George Voulgaris, John C. Warner

Faculty Publications

A series of process-oriented numerical simulations is carried out in order to evaluate the relative role of locally generated residual flow and overtides on net sediment transport over linear sandbanks. The idealized bathymetry and forcing are similar to those present in the Norfolk Sandbanks, North Sea. The importance of bottom drag parameterization and bank orientation with respect to the ambient flow is examined in terms of residual flow and overtide generation, and subsequent sediment transport implications are discussed. The results show that although the magnitudes of residual flow and overtides are sensitive to bottom roughness parameterization and bank orientation, the ...