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2008

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Full-Text Articles in Physical Sciences and Mathematics

Ssrn As An Initial Revolution In Academic Knowledge Aggregation And Dissemination, David Bray, Sascha Vitzthum, Benn Konsynski Jan 2010

Ssrn As An Initial Revolution In Academic Knowledge Aggregation And Dissemination, David Bray, Sascha Vitzthum, Benn Konsynski

Sascha Vitzthum

Within this paper we consider our results of using the Social Science Research Network (SSRN) over a period of 18 months to distribute our working papers to the research community. Our experiences have been quite positive, with SSRN serving as a platform both to inform our colleagues about our research as well as inform us about related research (through email and telephoned conversations of colleagues who discovered our paper on SSRN). We then discuss potential future directions for SSRN to consider, and how SSRN might well represent an initial revolution in 21st century academic knowledge aggregation and dissemination. Our paper ...


Automatic Reaction To A Chemical Event Detected By A Low-Cost Wireless Chemical Sensing Network, Stephen Beirne, King Tong Lau, Brian Corcoran, Dermot Diamond Dec 2008

Automatic Reaction To A Chemical Event Detected By A Low-Cost Wireless Chemical Sensing Network, Stephen Beirne, King Tong Lau, Brian Corcoran, Dermot Diamond

Faculty of Science - Papers (Archive)

A test-scale wireless chemical sensor network (WCSN) has been deployed within a controlled Environmental Chamber (EC). The combined signals from the WCSN were used to initiate a controllable response to the detected chemical event. When a particular sensor response pattern was obtained, a purging cycle was initiated. Sensor data were continuously checked against user-defined action limits, to determine if a chemical event had occurred. An acidic contaminant was used to demonstrate the response of the sensor network. Once the acid plume was simultaneously detected by a number of wireless chemical sensor nodes, an automatic response action, which was the purging ...


The 4 X 4 Semantic Model: Exploiting Data, Functional, Non-Functional And Execution Semantics Across Business Process, Workflow, Partner Services And Middleware Services Tiers, Amit P. Sheth, Karthik Gomadam Dec 2008

The 4 X 4 Semantic Model: Exploiting Data, Functional, Non-Functional And Execution Semantics Across Business Process, Workflow, Partner Services And Middleware Services Tiers, Amit P. Sheth, Karthik Gomadam

Kno.e.sis Publications

Business processes in the global environment increasingly encompass multiple partners and complex, rapidly changing requirements. In this context it is critical that strategic business objectives align with and map accurately to systems that support flexible and dynamic business processes. To support the demanding requirements of global business processes, we propose a comprehensive, unifying 4 X 4 Semantic Model that uses Semantic Templates to link four tiers of implementation with four types of semantics. The four tiers are the Business Process Tier, the Workflow Enactment Tier, the Partner Services Tier, and the Middleware Services Tier. The four types of semantics are ...


A Martingale Test For Alpha, Dean P. Foster, Robert A. Stine, H. Peyton Young Dec 2008

A Martingale Test For Alpha, Dean P. Foster, Robert A. Stine, H. Peyton Young

Statistics Papers

We present a new method for testing whether a fund manager’s track record allows us to infer that he is able to beat the market with high probability or is just plain lucky. The test is based on the martingale maximal inequality. Unlike other standard approaches the test is robust to the assumed distribution of returns while retaining substantial statistical power. The method is illustrated using stock market data from 1926‐2007.


Limnological Assistance For The Lake Mead National Recreation Area In Meeting The Challenge Of The Water 2025 Initiative: Quarterly Report, Period Ending December 31, 2008, Margaret N. Rees Dec 2008

Limnological Assistance For The Lake Mead National Recreation Area In Meeting The Challenge Of The Water 2025 Initiative: Quarterly Report, Period Ending December 31, 2008, Margaret N. Rees

Limnological Studies

Project 1: Technical input has been provided at four advisory team meetings attended this quarter.

Project 2: A formal report titled, Surface Water Monitoring for Indicator Bacteria in High-use Sites of the Lake Mead National Recreation Area, has been prepared; an accompanying poster presentation for the Lake Mead Science Symposium is in preparation.

Project 3: A draft document titled, “Interagency Monitoring Action Plan (I-MAP): Quagga Mussels in Lakes Mead and Mohave” has been presented to an interagency core group to review and input. Six oral presentations related to quagga mussels are in preparation by this group for the Lake Mead ...


Lake Mead National Recreation Area Sensitive Wildlife Species Monitoring And Analysis: Quarterly Progress Report, Period Ending December 31, 2008, Margaret N. Rees Dec 2008

Lake Mead National Recreation Area Sensitive Wildlife Species Monitoring And Analysis: Quarterly Progress Report, Period Ending December 31, 2008, Margaret N. Rees

Wildlife Monitoring

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

  • All milestones and deliverables associated with the MSHCP project are on schedule
  • Completion of 2008 monitoring survey efforts
  • Coordination is ongoing to identify potential translocation sites, including assisting efforts to identify a potential site in the western Grand Canyon
  • RLFCT meeting hosted and minutes of meeting drafted
  • Annual report provided to RLFCT, final draft in review
  • Sampling for the amphibian chytrid fungus conducted at many sites

Project 2. Bald Eagle Winter Monitoring and Evaluation

  • All MSHCP milestones and deliverables are on schedule
  • Planning and coordination of the 2009 Eagle Count conducted ...


Nevada Interagency Volunteer Program: Helping Hands Across Public Lands – Phase Ii: Quarterly Progress Report, Period Covering October 1 – December 31, 2008, Margaret N. Rees Dec 2008

Nevada Interagency Volunteer Program: Helping Hands Across Public Lands – Phase Ii: Quarterly Progress Report, Period Covering October 1 – December 31, 2008, Margaret N. Rees

Get Outdoors Nevada

  • The number of records in the volunteer database increased 8% over last quarter. The database now contains 6,431 records.
  • Website activity increased, recording an average of 56,013 hits per month, an increase of 6% from last quarter, with an average of 5,211 pages viewed per month.
  • Volunteer fall training has been completed.
  • Three National Public Land Day and National Family Events have been completed.
  • Two hundred and five people attended the Volunteer Recognition Event.


Global Distribution Of Atmospheric Phosphorus Sources, Concentrations And Deposition Rates, And Anthropogenic Impacts, Natalie Mahowald, Timothy D. Jickells, Alex R. Baker, Paulo Artaxo, Claudia R. Benitez-Nelson, Gilles Bergametti, Tami C. Bond, Ying Chen, David D. Cohen, Barak Herut, Nilgun Kubilay, Remi Losno, Chao Luo, Willy Maenhaut, Kenneth A. Mcgee, Gregory S. Okin, Ronald L. Siefert, Seigen Tsukuda Dec 2008

Global Distribution Of Atmospheric Phosphorus Sources, Concentrations And Deposition Rates, And Anthropogenic Impacts, Natalie Mahowald, Timothy D. Jickells, Alex R. Baker, Paulo Artaxo, Claudia R. Benitez-Nelson, Gilles Bergametti, Tami C. Bond, Ying Chen, David D. Cohen, Barak Herut, Nilgun Kubilay, Remi Losno, Chao Luo, Willy Maenhaut, Kenneth A. Mcgee, Gregory S. Okin, Ronald L. Siefert, Seigen Tsukuda

Faculty Publications

[1] A worldwide compilation of atmospheric total phosphorus (TP) and phosphate (PO4) concentration and deposition flux observations are combined with transport model simulations to derive the global distribution of concentrations and deposition fluxes of TP and PO4. Our results suggest that mineral aerosols are the dominant source of TP on a global scale (82%), with primary biogenic particles (12%) and combustion sources (5%) important in nondusty regions. Globally averaged anthropogenic inputs are estimated to be ∼5 and 15% for TP and PO4, respectively, and may contribute as much as 50% to the deposition over the oligotrophic ocean where productivity may ...


Back Matter Dec 2008

Back Matter

Journal of Digital Forensics, Security and Law

No abstract provided.


Front Matter Dec 2008

Front Matter

Journal of Digital Forensics, Security and Law

No abstract provided.


Masthead Dec 2008

Masthead

Journal of Digital Forensics, Security and Law

No abstract provided.


Detecting Topological Features Of Chaotic Fluid Flow, Nicholas T. Ouellette, Jerry P. Gollub Dec 2008

Detecting Topological Features Of Chaotic Fluid Flow, Nicholas T. Ouellette, Jerry P. Gollub

Department of Physics Papers

No abstract provided.


Quad General Tree Drawing Algorithm And General Trees Characterization: Towards An Environment For The Experimental Study On General Tree Drawing Algorithms, Chu Yao Dec 2008

Quad General Tree Drawing Algorithm And General Trees Characterization: Towards An Environment For The Experimental Study On General Tree Drawing Algorithms, Chu Yao

Theses and Dissertations

Information visualization produces (interactive) visual representations of abstract data to reinforce human cognition and perception; thus enabling the viewer to gain knowledge about the internal structure of the data and causal relationships in it. The visualization of information hierarchies is concerned with the presentation of abstract hierarchical information about relationships between various entities. It has many applications in diverse domains such as software engineering, information systems, biology, and chemistry. Information hierarchies are typically modeled by an abstract tree, where vertices are entities and edges represent relationships between entities. The aim of visualizing tree drawings is to automatically produce drawings of ...


A Note On The Sub-Optimality Of Rank Ordering Of Objects On The Basis Of The Leading Principal Component Factor Scores, Sudhanshu K. Mishra Dec 2008

A Note On The Sub-Optimality Of Rank Ordering Of Objects On The Basis Of The Leading Principal Component Factor Scores, Sudhanshu K. Mishra

Sudhanshu K Mishra

This paper demonstrates that if we intend to optimally rank order n objects (candidates) each of which has m rank-ordered attributes or rank scores have been awarded by m evaluators, then the overall ordinal ranking of objects by the conventional principal component based factor scores turns out to be suboptimal. Three numerical examples have been provided to show that principal component based rankings do not necessarily maximize the sum of squared correlation coefficients between the individual m rank scores arrays, X(n,m), and overall rank scores array, Z(n).


Casimir Effect For Massless Fermions In One Dimension: A Force-Operator Approach, Dina Zhabinskaya, Jesse M. Kinder, Eugene J. Mele Dec 2008

Casimir Effect For Massless Fermions In One Dimension: A Force-Operator Approach, Dina Zhabinskaya, Jesse M. Kinder, Eugene J. Mele

Department of Physics Papers

We calculate the Casimir interaction between two short-range scatterers embedded in a background of one-dimensional massless Dirac fermions using a force-operator approach. We obtain the force between two finite-width square barriers and take the limit of zero width and infinite potential strength to study the Casimir force mediated by the fermions. For the case of identical scatterers, we recover the conventional attractive one-dimensional Casimir force. For the general problem with inequivalent scatterers, we find that the magnitude and sign of this force depend on the relative spinor polarizations of the two scattering potentials, which can be tuned to give an ...


Step-Wise Changes In Glacier Flow Speed Coincide With Calving And Glacial Earthquakes At Helheim Glacier, Greenland, M. Nettles, T. B. Larsen, P. Elósegui, Gordon S. Hamilton, Leigh A. Stearns, A. P. Ahlstrom, J. L. Davis, M. L. Andersen, J. De Juan, S. A. Khan, L. Stensing, G. Ekstrom, R. Forsberg Dec 2008

Step-Wise Changes In Glacier Flow Speed Coincide With Calving And Glacial Earthquakes At Helheim Glacier, Greenland, M. Nettles, T. B. Larsen, P. Elósegui, Gordon S. Hamilton, Leigh A. Stearns, A. P. Ahlstrom, J. L. Davis, M. L. Andersen, J. De Juan, S. A. Khan, L. Stensing, G. Ekstrom, R. Forsberg

Earth Science Faculty Scholarship

Geodetic observations show several large, sudden increases in flow speed at Helheim Glacier, one of Greenland's largest outlet glaciers, during summer, 2007. These step-like accelerations, detected along the length of the glacier, coincide with teleseismically detected glacial earthquakes and major iceberg calving events. No coseismic offset in the position of the glacier surface is observed; instead, modest tsunamis associated with the glacial earthquakes implicate glacier calving in the seismogenic process. Our results link changes in glacier velocity directly to calving-front behavior at Greenland's largest outlet glaciers, on timescales as short as minutes to hours, and clarify the mechanism ...


Topological Structures In The Equities Market Network, Gregory Leibon, Scott Pauls, Daniel Rockmore, Robert Savell Dec 2008

Topological Structures In The Equities Market Network, Gregory Leibon, Scott Pauls, Daniel Rockmore, Robert Savell

Open Dartmouth: Peer-reviewed articles by Dartmouth faculty

We present a new method for articulating scale-dependent topological descriptions of the network structure inherent in many complex systems. The technique is based on “partition decoupled null models,” a new class of null models that incorporate the interaction of clustered partitions into a random model and generalize the Gaussian ensemble. As an application, we analyze a correlation matrix derived from 4 years of close prices of equities in the New York Stock Exchange (NYSE) and National Association of Securities Dealers Automated Quotation (NASDAQ). In this example, we expose (i) a natural structure composed of 2 interacting partitions of the market ...


Structure Of Polc Reveals Unique Dna Binding And Fidelity Determinants, Ronald J. Evans, Douglas R. Davies, James M. Bullard, Jeffrey Christensen, Louis S. Green, Joseph W. Guiles, Janice D. Pata, Wendy K. Ribble, Nebojsa Janjic, Thale C. Jarvis Dec 2008

Structure Of Polc Reveals Unique Dna Binding And Fidelity Determinants, Ronald J. Evans, Douglas R. Davies, James M. Bullard, Jeffrey Christensen, Louis S. Green, Joseph W. Guiles, Janice D. Pata, Wendy K. Ribble, Nebojsa Janjic, Thale C. Jarvis

Chemistry Faculty Publications and Presentations

PolC is the polymerase responsible for genome duplication in many Gram-positive bacteria and represents an attractive target for antibacterial development. We have determined the 2.4-Å resolution crystal structure of Geobacillus kaustophilus PolC in a ternary complex with DNA and dGTP. The structure reveals nascent base pair interactions that lead to highly accurate nucleotide incorporation. A unique β-strand motif in the PolC thumb domain contacts the minor groove, allowing replication errors to be sensed up to 8 nt upstream of the active site. PolC exhibits the potential for large-scale conformational flexibility, which could encompass the catalytic residues. The structure suggests ...


Sub-Micron Parallel Laser Direct-Write, Christina Othon, Arnoldo Laracuente, H Ladoucuer, Bradley Ringeisen Dec 2008

Sub-Micron Parallel Laser Direct-Write, Christina Othon, Arnoldo Laracuente, H Ladoucuer, Bradley Ringeisen

Christina M Othon

We have developed a modified laser induced forward transfer (LIFT) technique which allows for the parallel deposition of hundreds of sub-micron features. The approach utilizes a self-assembled monolayer of monodisperse polystyrene microspheres as the focusing element. A monolayer of close-packed microspheres is formed on top of an ultra-thin quartz support (25 m thick), and a metallic thin film is then deposited on the underside of the quartz. This approach is different from previous parallel microsphere-assisted LIFT experiments that required the deposition of metal directly onto the surface of the periodic microsphere structure. For this study, an 800 nm, 130 fs ...


Laser-Induced Photon-Branched Chain Reaction In A Chemically-Active Gas-Dispersed Medium, Thomas George, Renat Letfullin, Galen Duree Dec 2008

Laser-Induced Photon-Branched Chain Reaction In A Chemically-Active Gas-Dispersed Medium, Thomas George, Renat Letfullin, Galen Duree

Chemistry & Biochemistry Faculty Works

A promising avenue in the development of high-energy pulsed chemical HF/DF lasers and amplifiers is the utilization of a photon-branched chain reaction initiated in a two-phase active medium, that is, a medium containing a laser working gas and ultradispersed passivated metal particles. These particles are evaporated under the action of IR laser radiation which results in the appearance of free atoms, their diffusion into the gas, and the development of a photon-branching chain process, which involves photons as both reactants and products. The key obstacle here is the formation of a relatively large volume (in excess of 10^3 ...


The June 2008 Flare Of Markarian 421 From Optical To Tev Energies, P. T. Reynolds, Et Al Dec 2008

The June 2008 Flare Of Markarian 421 From Optical To Tev Energies, P. T. Reynolds, Et Al

Physical Sciences Publications

We present optical, X-ray, high-energy (30 GeV) and very high energy (100 GeV; VHE) observations of the high-frequency peaked blazar Mrk 421 taken between 2008 May 24 and June 23. A high-energy γ-ray signal was detected by AGILE with between June 9 and 15, with F(E>100 MeV) = 42+14 –12 × 10–8 photons cm–2 s–1. This flaring state is brighter than the average flux observed by EGRET by a factor of ~3, but still consistent with the highest EGRET flux. In hard X-rays (20-60 keV) SuperAGILE resolved a five-day flare (June 9-15) peaking at ~55 mCrab ...


Laser-Induced Photon-Branched Chain Reaction In A Chemically-Active Gas-Dispersed Medium, Thomas F. George, Renat R. Letfullin, Galen C. Duree Dec 2008

Laser-Induced Photon-Branched Chain Reaction In A Chemically-Active Gas-Dispersed Medium, Thomas F. George, Renat R. Letfullin, Galen C. Duree

Thomas George

A promising avenue in the development of high-energy pulsed chemical HF/DF lasers and amplifiers is the utilization of a photon-branched chain reaction initiated in a two-phase active medium, that is, a medium containing a laser working gas and ultradispersed passivated metal particles. These particles are evaporated under the action of IR laser radiation which results in the appearance of free atoms, their diffusion into the gas, and the development of a photon-branching chain process, which involves photons as both reactants and products. The key obstacle here is the formation of a relatively large volume (in excess of 10^3 ...


Analysis Of Adverse Events In Drug Safety: A Multivariate Approach Using Stratified Quasi-Least Squares, Hanjoo Kim, Justine Shults, Scott Patterson, Robert Goldberg-Alberts Dec 2008

Analysis Of Adverse Events In Drug Safety: A Multivariate Approach Using Stratified Quasi-Least Squares, Hanjoo Kim, Justine Shults, Scott Patterson, Robert Goldberg-Alberts

UPenn Biostatistics Working Papers

Safety assessment in drug development involves numerous statistical challenges, and yet statistical methodologies and their applications to safety data have not been fully developed, despite a recent increase of interest in this area. In practice, a conventional univariate approach for analysis of safety data involves application of the Fisher's exact test to compare the proportion of subjects who experience adverse events (AEs) between treatment groups; This approach ignores several common features of safety data, including the presence of multiple endpoints, longitudinal follow-up, and a possible relationship between the AEs within body systems. In this article, we propose various regression ...


Synthesis Analysis Of Regression Models With A Continuous Outcome, Andrew Zhou, Nan Hu, Guizhou Hu, Martin Root Dec 2008

Synthesis Analysis Of Regression Models With A Continuous Outcome, Andrew Zhou, Nan Hu, Guizhou Hu, Martin Root

UW Biostatistics Working Paper Series

Synthesis Analysis of Regression Models with a Continuous Outcome Xiao-Hua Zhou 1,2, Nan Hu 2, Guizhou Hu3, and Martin Root3 1 HSR&D Center of Excellence, VA Puget Sound Health Care System, Seattle, WA 98101. 2 Department of Biostatistics, University of Washington, Seattle, WA 98195. 3 BioSignia, Inc., 1822 East NC Highway 54, Suite 350, Durham, NC 27713 To estimate the multivariate regression model from multiple individual studies, it would be challenging to obtain results if the input from individual studies only provide univariate or incomplete multivariate regression information. Samsa et al [1] proposed a simple method to combine ...


Final Report: Task 22 — Extreme Ground Motion Studies, John G. Anderson, James N. Brune, Jaak J.K. Daemen, Matthew Purvance Dec 2008

Final Report: Task 22 — Extreme Ground Motion Studies, John G. Anderson, James N. Brune, Jaak J.K. Daemen, Matthew Purvance

Publications (YM)

TASK 22 consisted of two separate investigations into extreme ground motions due to seismic events, Subtask 1 and Subtask 2. Subtask 1 included field studies of geological formations that should put an upper bound on extreme ground motions that have happened at the site of the formations. The locations are critically selected to provide the most effective constraints possible on the validity of the probabilistic seismic hazard analysis for Yucca Mountain. Subtask 2 surveyed recorded ground motions from around the world, with the aim to draw general conclusions from these as to the conditions where extreme ground motions are observed ...


Structure And Dynamics Of Metalloproteins In Live Cells, Jeremy D. Cook, James E. Penner-Hahn, Timothy L. Stemmler Dec 2008

Structure And Dynamics Of Metalloproteins In Live Cells, Jeremy D. Cook, James E. Penner-Hahn, Timothy L. Stemmler

Biochemistry and Molecular Biology Faculty Publications

X-ray absorption spectroscopy (XAS) has emerged as one of the premier tools for investigating the structure and dynamic properties of metals in cells and in metal containing biomolecules. Utilizing the high flux and broad energy range of X-rays supplied by synchrotron light sources, one can selectively excite core electronic transitions in each metal. Spectroscopic signals from these electronic transitions can be used to dissect the chemical architecture of metals in cells, in cellular components and in biomolecules at varying degrees of structural resolution. With the development of ever-brighter X-ray sources, X-ray methods have grown into applications that can be utilized ...


Is The Pamela Positron Excess Winos?, Scott Watson, Phill Grajek, Gordon L. Kane, Daniel J. Phalen, Aaron Pierce Dec 2008

Is The Pamela Positron Excess Winos?, Scott Watson, Phill Grajek, Gordon L. Kane, Daniel J. Phalen, Aaron Pierce

Physics

Recently the PAMELA satellite-based experiment reported an excess of galactic positrons that could be a signal of annihilating dark matter. The PAMELA data may admit an interpretation as a signal from a wino-like LSP of mass about 200 GeV, normalized to the local relic density, and annihilating mainly into W-bosons. This possibility requires the current conventional estimate for the energy loss rate of positrons be too large by roughly a factor of five. Data from anti-protons and gamma rays also provide tension with this interpretation, but there are significant astrophysical uncertainties associated with their propagation. It is not unreasonable to ...


Energy-Efficient Peer-To-Peer Caching And Mobility Management In 4g Hybrid Networks, Mehdi Azami, Bharat Bhargava Dec 2008

Energy-Efficient Peer-To-Peer Caching And Mobility Management In 4g Hybrid Networks, Mehdi Azami, Bharat Bhargava

Department of Computer Science Technical Reports

No abstract provided.


Gravitational Wave Burst Source Direction Estimation Using Time And Amplitude Information, J. Markowitz, M. Zanolin, L. Cadonati, E. Katsavounidis Dec 2008

Gravitational Wave Burst Source Direction Estimation Using Time And Amplitude Information, J. Markowitz, M. Zanolin, L. Cadonati, E. Katsavounidis

Publications

In this article we study two problems that arise when using timing and amplitude estimates from a network of interferometers (IFOs) to evaluate the direction of an incident gravitational wave burst (GWB). First, we discuss an angular bias in the least squares timing-based approach that becomes increasingly relevant for moderate to low signal-to-noise ratios. We show how estimates of the arrival time uncertainties in each detector can be used to correct this bias. We also introduce a stand alone parameter estimation algorithm that can improve the arrival time estimation and provide root-sum-squared strain amplitude (h(rss)) values for each site ...


Intelligent Multimedia Delivery? It’S A Question Of Semantics, Joseph Thomas-Kerr, I. Burnett, C. Ritz Dec 2008

Intelligent Multimedia Delivery? It’S A Question Of Semantics, Joseph Thomas-Kerr, I. Burnett, C. Ritz

Ian Burnett

Intelligent multimedia delivery uses semantic information about content to enhance the delivery process. This paper proposes a model for intelligent multimedia delivery that advances the state of the art by incorporating a concept of semantic distortion into the delivery optimization process. Furthermore, the model combines format-independence with rate-distortion optimization to provide a flexible framework for intelligent delivery of multimedia in existing and future formats. The paper provides a review of the existing work covering components of the model: scalable coding formats, rate-distortion optimization, format-independent adaptation, and semantic adaptation. It then details the model, and identifies open problems and opportunities for ...