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

Physical Sciences and Mathematics Commons™

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

2010

Discipline
Institution
Keyword
Publication
Publication Type
File Type

Articles 1711 - 1740 of 8620

Full-Text Articles in Physical Sciences and Mathematics

Background Fluorescence In Groundwater From A Tropical Karst Island Aquifer, Michelle Hoffman Sep 2010

Background Fluorescence In Groundwater From A Tropical Karst Island Aquifer, Michelle Hoffman

Michelle Hoffman

Background levels of four fluorescent compounds were monitored biweekly at thirteen sampling sites on Guam, consisting of subtidal and intertidal springs, dissolution fractures, and internal upland contact spring discharge, over a 13-month period from 2006 to 2007. Samples were compared to local precipitation and to seawater samples from four nearby reef flats. The data revealed that the concentrations of optical brighteners were consistently two orders of magnitude greater than either sodium fluorescein or rhodamine WT, while Eosine Y was rarely detected. Background levels in seawater, by comparison, accounted for 25% or more of the fluorescent compounds detected at the thirteen …

Go to article

An Explicit Super‐Time‐Stepping Scheme For Non‐Symmetric Parabolic Problems, Stephen O'Sullivan, Katharine Gurski Sep 2010

An Explicit Super‐Time‐Stepping Scheme For Non‐Symmetric Parabolic Problems, Stephen O'Sullivan, Katharine Gurski

Conference papers

Explicit numerical methods for the solution of a system of differential equations may suffer from a time step size that approaches zero in order to satisfy stability conditions. When the differential equations are dominated by a skew-symmetric component, the problem is that the real eigenvalues are dominated by imaginary eigenvalues. We compare results for stable time step limits for the super-time-stepping method of Alexiades, Amiez, and Gremaud (super-time-stepping methods belong to the Runge-Kutta-Chebyshev class) and a new method modeled on a predictor-corrector scheme with multiplicative operator splitting. This new explicit method increases stability of the original super-time-stepping whenever the skew-symmetric …

Go to article

Relativistic Particle Acceleration In Tangled Magnetic Fields, Stephen O'Sullivan, Brian Reville, Andrew Taylor Sep 2010

Relativistic Particle Acceleration In Tangled Magnetic Fields, Stephen O'Sullivan, Brian Reville, Andrew Taylor

Conference papers

We present simulations of the transport of fast particles through three-dimensional turbulent magnetic field configurations. A time dependency is imposed on the plane wave modes used in constructing these fields such than acceleration via the second-order Fermi process is possible. We consider simulations of models with low and high turbulence levels for non-relativistic waves. The predictions of quasi-linear theory are discussed with respect to the simulation data. We conclude that for pure stochastic acceleration via Alfvén waves to be plausible as the generator of UHECR in Cen A, the baryon number density would need to be several orders of magnitude …

Go to article

Investigating Ultrasonic Positioning On Mobile Phones, Viacheslav Filonenko, Charlie Cullen, James Carswell Sep 2010

Investigating Ultrasonic Positioning On Mobile Phones, Viacheslav Filonenko, Charlie Cullen, James Carswell

Conference papers

In this paper we evaluate the innate ability of mobile phone speakers to produce ultrasound and the possible uses of this ability for accurate indoor positioning. The frequencies in question are a range between 20 and 22 KHz, which is high enough to be inaudible but low enough to be generated by standard sound hardware. A range of tones is generated at different volume settings on several popular modern mobile phones with the aim of finding points of failure. Our results indicate that it is possible to generate the given range of frequencies without significant distortions, provided the signal volume …

Go to article

Circular Dichroism Spectroscopy In The Undergraduate Curriculum, Adam R. Urbach Sep 2010

Circular Dichroism Spectroscopy In The Undergraduate Curriculum, Adam R. Urbach

Chemistry Faculty Research

Circular dichroism spectropolarimetry (CD) is a method of optical spectroscopy that seems in most practical ways like UV−visible spectroscopy. The main difference between the two methods is that CD, instead of measuring the absorbance of light as a function of wavelength, measures the difference in absorbance of left versus right circularly polarized light as a function of wavelength. A CD spectrum is an observation of the structure of a chiral compound; it often serves as a “fingerprint” of the structure of biological molecules such as proteins and nucleic acids. For this reason, CD has been broadly applied in biochemistry and …

Go to article

Sql Querie Recommendations: A Query Fragment-Based Approach, Jayad Akbarnejad, Magdalini Eirinaki, Suju Koshy, Duc On, Neoklis Polyzotis Sep 2010

Sql Querie Recommendations: A Query Fragment-Based Approach, Jayad Akbarnejad, Magdalini Eirinaki, Suju Koshy, Duc On, Neoklis Polyzotis

Faculty Publications

Relational database systems are becoming increasingly popular in the scientific community to support the interactive exploration of large volumes of data. In this scenario, users employ a query interface (typically, a web-based client) to issue a series of SQL queries that aim to analyze the data and mine it for interesting information. First-time users, however, may not have the necessary knowledge to know where to start their exploration. Other times, users may simply overlook queries that retrieve important information. In this work we describe a framework to assist non-expert users by providing personalized query recommendations. The querying behavior of the …

Go to article

Personal Vs. Social, Magdalini Eirinaki Sep 2010

Personal Vs. Social, Magdalini Eirinaki

Faculty Publications

The last few years we witnessed an impressive growth in social networks and in applications that add value to their amassed information. At the same time, the continuing expansion of mobile platforms and applications (e.g. iPhone), combined with the overwhelming supply of information and services, makes effective personalization and context-awareness much required features. One may consider "personal" and "social" data management as comprising two distinct directions with conflicting characteristics. However, it can be argued that they complement each other and that in future applications they will ultimately converge. This "personal vs. social" predicament presents a number of interesting topics that …

Go to article

Diffeomorphic Approximation Of Sobolev Homeomorphisms, Tadeusz Iwaniec, Leonid V. Kovalev, Jani Onninen Sep 2010

Diffeomorphic Approximation Of Sobolev Homeomorphisms, Tadeusz Iwaniec, Leonid V. Kovalev, Jani Onninen

Mathematics - All Scholarship

Every homeomorphism h: X -> Y between planar open sets that belongs to the Sobolev class W1;p(X;Y), 1 < p < 1, can be approximated in the Sobolev norm by Cinfinity -smooth dieomorphisms.

Go to article

Coarser Connected Metrizable Topologies, Lynne Yengulalp Sep 2010

Coarser Connected Metrizable Topologies, Lynne Yengulalp

Mathematics Faculty Publications

We show that every metric space, X, with w(⩾) c has a coarser connected metrizable topology.

Go to article

Freshwater Fishes Of South Carolina By Fred C. Rohde, Rudolf G. Arndt, Jeffrey W. Foltz, And Joseph M. Quattro With Photographs By Fred C. Rohde-Book Review, Martin O'Connell Sep 2010

Freshwater Fishes Of South Carolina By Fred C. Rohde, Rudolf G. Arndt, Jeffrey W. Foltz, And Joseph M. Quattro With Photographs By Fred C. Rohde-Book Review, Martin O'Connell

Earth and Environmental Sciences Faculty Publications

No abstract provided.

Go to article

Studies Of Insulating Superconductors, Shawna M. Hollen, J C. Joy, Maura Lynch, H Q. Nguyen, M D. Stewart Jr, J Shainline, Aijun Yin, J M. Xu, J M. Valles Jr. Sep 2010

Studies Of Insulating Superconductors, Shawna M. Hollen, J C. Joy, Maura Lynch, H Q. Nguyen, M D. Stewart Jr, J Shainline, Aijun Yin, J M. Xu, J M. Valles Jr.

Physics & Astronomy

No abstract provided.

Go to article

High Resolution Calibration Of A Multibeam Echo Sounder, Carlo Lanzoni, Thomas C. Weber Sep 2010

High Resolution Calibration Of A Multibeam Echo Sounder, Carlo Lanzoni, Thomas C. Weber

Center for Coastal and Ocean Mapping

Calibration can greatly increase the utility of collecting seafloor backscattering strength with multibeam echo sounders (MBES). A calibration procedure to determine high resolution, three dimensional transmit and receive beam patterns of a Reson SeaBat 7125 MBES was performed using the fresh water calibration tank at the University of New Hampshire. The measurements employed an omni-directional Reson TC4034 projector/hydrophone as a reference transducer at an acoustic distance of 13 m. The multibeam sonar system was configured for 256 beams equi-angle mode and operating frequency of 396 kHz. The transmit beam pattern was computed for across-track angular range between +/–90o in 0.1o …

Go to article

Macroevolutionary Patterns In The Evolutionary Radiation Of Archosaurs (Tetrapoda: Diapsida), S. L. Brusatte, M. J. Benton, G. T. Lloyd, M. Ruta, Steve C. Wang Sep 2010

Macroevolutionary Patterns In The Evolutionary Radiation Of Archosaurs (Tetrapoda: Diapsida), S. L. Brusatte, M. J. Benton, G. T. Lloyd, M. Ruta, Steve C. Wang

Mathematics & Statistics Faculty Works

The rise of archosaurs during the Triassic and Early Jurassic has been treated as a classic example of an evolutionary radiation in the fossil record. This paper reviews published studies and provides new data on archosaur lineage origination, diversity and lineage evolution, morphological disparity, rates of morphological character change, and faunal abundance during the Triassic–Early Jurassic. The fundamental archosaur lineages originated early in the Triassic, in concert with the highest rates of character change. Disparity and diversity peaked later, during the Norian, but the most significant increase in disparity occurred before maximum diversity. Archosaurs were rare components of Early–Middle Triassic …

Go to article

A Generalised Kummer's Conjecture, M. J.R. Myers Sep 2010

A Generalised Kummer's Conjecture, M. J.R. Myers

University Faculty Publications and Creative Works

Kummer's conjecture predicts the rate of growth of the relative class numbers of cyclotomic fields of prime conductor. We extend Kummer's conjecture to cyclotomic fields of conductor n, where n is any natural number. We show that the Elliott-Halberstam conjecture implies that this generalised Kummer's conjecture is true for almost all n but is false for infinitely many n.

Go to article

Investigation Of Crustal Structure Of Turkey By Means Of Gravity Data, Selim Arslan, Uğur Akin, Atakan Alaca Sep 2010

Investigation Of Crustal Structure Of Turkey By Means Of Gravity Data, Selim Arslan, Uğur Akin, Atakan Alaca

Bulletin of the Mineral Research and Exploration

During this work, the regional gravity data acquired earlier were used and in order to investigate the relations between geology - tectonics and elevation, isostatic map of Turkey, free air anomaly map and Bouguer anomaly maps were obtained, and comparisons with respect to elevations were carried out. For the thickness of the earth crust T 0 32 - 0.08g relation was used. The best relation was obtained from Bouguer anomaly with +0.65 coefficient; the relation function was obtained as Y = - 72E + 7.77. Thickness of the crust of Turkey is estimated to be 31.4 km where it is …

Go to article

Actual Bloedite Mineral Precipitation In A Seasonal Lake In Çankiri-Çorum Basin, İlhan Sönmez Sep 2010

Actual Bloedite Mineral Precipitation In A Seasonal Lake In Çankiri-Çorum Basin, İlhan Sönmez

Bulletin of the Mineral Research and Exploration

Bloedite (Na2Mg(SO4)2.4H2O) which is an economically important sodium sulfate mineral currently precipitates through evaporation in Lake İshaklı, a small seasonal lake (playa lake) situated to the north of İshaklı Village (Bayat - Çorum) in Çankırı-Çorum Basin. Lake İshaklı, in which actual bloedite precipitation has been determined for the first time by this work in Turkey, extends in East-West direction and covers an area of approximately 220 000 m2 . During winter and spring months it becomes a lake with a depth of more than 2 m. However, during hot periods when evaporation …

Go to article

Engaging Students In Information Storage Management Courses, Vladan Jovanovic, Timur Mirzoev, Lee Toderick, Rick Homkes, Mark Stockman Sep 2010

Engaging Students In Information Storage Management Courses, Vladan Jovanovic, Timur Mirzoev, Lee Toderick, Rick Homkes, Mark Stockman

Department of Computer Science Faculty Publications

This panel will elaborate on faculty experiences with specific ways used to engage students in the Information Storage and Management, formerly Storage Technology, and the Virtualization coursework. The emphasize of the discussion will be on the mechanisms used in engaging students in learning and on experiences with various activities helpful for varying learning preferences/modes. All invited panelists are experienced faculty involved with subject matter courses via EMC’s Academic Alliance program. The resources made available via this alliance and through exchange among the faculty involved in teaching related subjects in IT and CS programs will be discussed and evaluated. The impact …

Go to article

Review Of "The Science On Women And Science" Edited By C. H. Sommers, Amy Lisa Graves Sep 2010

Review Of "The Science On Women And Science" Edited By C. H. Sommers, Amy Lisa Graves

Physics & Astronomy Faculty Works

No abstract provided.

Go to article

Scenario-Based And Value-Based Specification Mining: Better Together, David Lo, Shahar Maoz Sep 2010

Scenario-Based And Value-Based Specification Mining: Better Together, David Lo, Shahar Maoz

Research Collection School Of Computing and Information Systems

Specification mining takes execution traces as input and extracts likely program invariants, which can be used for comprehension, verification, and evolution related tasks. In this work we integrate scenario-based specification mining, which uses data-mining algorithms to suggest ordering constraints in the form of live sequence charts, an inter-object, visual, modal, scenario-based specification language, with mining of value-based invariants, which detects likely invariants holding at specific program points. The key to the integration is a technique we call scenario-based slicing, running on top of the mining algorithms to distinguish the scenario-specific invariants from the general ones. The resulting suggested specifications are …

Go to article

Baryon Acoustic Oscillations In 2d: Modeling Redshift-Space Power Spectrum From Perturbation Theory, Atsushi Taruya, Takahiro Nishimichi, Shun Saito Sep 2010

Baryon Acoustic Oscillations In 2d: Modeling Redshift-Space Power Spectrum From Perturbation Theory, Atsushi Taruya, Takahiro Nishimichi, Shun Saito

Physics Faculty Research & Creative Works

We present an improved prescription for the matter power spectrum in redshift space taking proper account of both nonlinear gravitational clustering and redshift distortion, which are of particular importance for accurately modeling baryon acoustic oscillations (BAOs). Contrary to the models of redshift distortion phenomenologically introduced but frequently used in the literature, the new model includes the corrections arising from the nonlinear coupling between the density and velocity fields associated with two competitive effects of redshift distortion, i.e., Kaiser and Finger-of-God effects. Based on the improved treatment of perturbation theory for gravitational clustering, we compare our model predictions with the monopole …

Go to article

Relation Between Transmission And Energy Stored In Random Media With Gain, Ben Payne, Jonathan Andreasen, Hui Cao, Alexey Yamilov Sep 2010

Relation Between Transmission And Energy Stored In Random Media With Gain, Ben Payne, Jonathan Andreasen, Hui Cao, Alexey Yamilov

Physics Faculty Research & Creative Works

In this work, we investigate a possibility of using the ratio between optical transmission, T, and energy stored inside the system, E, as a quantitative measure of the enhanced mesoscopic corrections to diffusive transport of light through a random medium with gain. We obtain an expression for T/E as a function of amplification strength in the diffusive approximation and show that it does not a have tendency to diverge when the threshold for random lasing is approached, as both T and E do. Furthermore, we find that a change in T/E signifies a change in the electric field distribution inside …

Go to article

Effects Of Bubbles And Sea Spray On Air–Sea Exchange In Hurricane Conditions, Alexander Soloviev, Roger Lukas Sep 2010

Effects Of Bubbles And Sea Spray On Air–Sea Exchange In Hurricane Conditions, Alexander Soloviev, Roger Lukas

Marine & Environmental Sciences Faculty Articles

The lower limit on the drag coefficient under hurricane force winds is determined by the break-up of the air–sea interface due to Kelvin–Helmholtz instability and formation of the two-phase transition layer consisting of sea spray and air bubbles. As a consequence, a regime of marginal stability develops. In this regime, the air–sea drag coefficient is determined by the turbulence characteristics of the two-phase transition layer. The upper limit on the drag coefficient is determined by the Charnock-type wave resistance. Most of the observational estimates of the drag coefficient obtained in hurricane conditions and in laboratory experiments appear to lie between …

Go to article

Comparison Of Non-Surgical And Surgical Endodontic Retreatment: A Systematic Review, Robert Corr Sep 2010

Comparison Of Non-Surgical And Surgical Endodontic Retreatment: A Systematic Review, Robert Corr

Loma Linda University Electronic Theses, Dissertations & Projects

Primary root canal therapy has been shown to be a predictable procedure with a high degree of success 1-4, however failures can occur after treatment. Treatment options for the preservation of teeth that have had previous endodontic treatment but demonstrate persistent disease include non-surgical (orthograde) or surgical (retrograde) endodontic retreatment, assuming the tooth is restorable, periodontally sound, and the patient desires to retain the tooth. The purpose of this study was to conduct a systematic review of the current available evidence to compare the clinical and radiographic outcomes of nonsurgical with those of surgical endodontic retreatment. Methodology began with …

Go to article

Do Online Reviews Reflect A Product’S True Perceived Quality? An Investigation Of Online Movie Reviews Across Cultures, Noi Sian Koh, Nan Hu, Eric K. Clemons Sep 2010

Do Online Reviews Reflect A Product’S True Perceived Quality? An Investigation Of Online Movie Reviews Across Cultures, Noi Sian Koh, Nan Hu, Eric K. Clemons

Research Collection School Of Computing and Information Systems

This paper investigates when the reported average of online ratings matches the perceived average assessment of the population as a whole, including the average assessments of both raters and non-raters. We apply behavioral theory to capture intentions in rating online movie reviews in two dissimilar countries – China and the United States. We argue that consumers’ rating behaviors are affected by cultural influences and that they are influenced in predictable ways. Based on data collected from IMDB.com and Douban.com, we found significant differences across raters from these two different cultures. Additionally, we examined how cultural elements influence rating behavior for …

Go to article

Shortest Path Computation On Air Indexes, Georgios Kellaris, Kyriakos Mouratidis Sep 2010

Shortest Path Computation On Air Indexes, Georgios Kellaris, Kyriakos Mouratidis

Research Collection School Of Computing and Information Systems

Shortest path computation is one of the most common queries in location-based services that involve transportation net- works. Motivated by scalability challenges faced in the mo- bile network industry, we propose adopting the wireless broad- cast model for such location-dependent applications. In this model the data are continuously transmitted on the air, while clients listen to the broadcast and process their queries locally. Although spatial problems have been considered in this environment, there exists no study on shortest path queries in road networks. We develop the rst framework to compute shortest paths on the air, and demonstrate the practicality and …

Go to article

Sensitivity Of Geoelectrical Measurements To The Presence Of Bacteria In Porous Media, Gamal Z. Abdel Aal, Estella A. Atekwana, Silvia Rossbach, D. Dale Werkema Sep 2010

Sensitivity Of Geoelectrical Measurements To The Presence Of Bacteria In Porous Media, Gamal Z. Abdel Aal, Estella A. Atekwana, Silvia Rossbach, D. Dale Werkema

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

We investigated the sensitivity of low-frequency electrical measurements (0.1-1000 Hz) to (1) microbial cell density, (2) live and dead cells, and (3) microbial attachment onto mineral surfaces of clean quartz sands and iron oxide-coated sands. Three strains of Pseudomonas aeruginosa PAO1 (wild type and rhlA and pilA mutant) with different motility and attachment properties were used. Varying concentrations of both live and dead cells of P. aeruginosa wild type in sand columns showed no effect on the real conductivity component (σ′). However, the imaginary conductivity component (σ″) increased linearly with increasing concentrations of live cells in sand columns, whereas minimal …

Go to article

Sol-Gel Synthesis And Characterisation Of Novel Metal Oxide Nanomaterials For Photocatalytic Applications, Nicholas T. Nolan Sep 2010

Sol-Gel Synthesis And Characterisation Of Novel Metal Oxide Nanomaterials For Photocatalytic Applications, Nicholas T. Nolan

Doctoral

This thesis presents a study of the effect of chemical modifiers and dopants on both the anatase to rutile transformation and also the photocatalytic efficiency of semiconductor nanomaterials. The main focus of the work is based on the crystallisation and phase transformation of the widely investigated semiconductor metal oxide, titanium dioxide (TiO2) Of the three polymorphs associated with titanium dioxide, anatase is widely regarded as the most effective photocatalyst. Typically anatase will transform to rutile in the temperature range 600 – 700 °C however, modification of a titanium precursor with a chelating agent can result in extended transformation temperature. The …

Go to article

Modeling Acoustic Scattering From The Seabed Using Transport Theory, Jorge Quijano, Lisa M. Zurk Sep 2010

Modeling Acoustic Scattering From The Seabed Using Transport Theory, Jorge Quijano, Lisa M. Zurk

Electrical and Computer Engineering Faculty Publications and Presentations

Radiative Transfer (RT) theory has established itself as an important tool for electromagnetic remote sensing in parallel plane geometries with random distributions of scatterers, and most recently it has also been proposed as a model for the propagation of elastic waves in layered ocean sediments. In this work the capabilities of this model are illustrated, as the RT method is used to predict backscattering strength from laboratory models of random media. The RT model is characterized by its flexibility on accommodating scatterers in a broad variety of sizes, shapes, and acoustic contrast relative to the background media. Additionally, this formulation …

Go to article

A Taxonomy-Based Model For Expertise Extrapolation, Delroy H. Cameron, Boanerges Aleman-Meza, Ismailcem Budak Arpinar, Sheron L. Decker, Amit P. Sheth Sep 2010

A Taxonomy-Based Model For Expertise Extrapolation, Delroy H. Cameron, Boanerges Aleman-Meza, Ismailcem Budak Arpinar, Sheron L. Decker, Amit P. Sheth

Kno.e.sis Publications

While many ExpertFinder applications succeed in finding experts, their techniques are not always designed to capture the various levels at which expertise can be expressed. Indeed, expertise can be inferred from relationships between topics and subtopics in a taxonomy. The conventional wisdom is that expertise in subtopics is also indicative of expertise in higher level topics as well. The enrichment of Expertise Profiles for finding experts can therefore be facilitated by taking domain hierarchies into account. We present a novel semantics-based model for finding experts, expertise levels and collaboration levels in a peer review context, such as composing a Program …

Go to article

Ranking Documents Semantically Using Ontological Relationships, Boanerges Aleman-Meza, I. Budak Arpinar, Mustafa V. Nural, Amit P. Sheth Sep 2010

Ranking Documents Semantically Using Ontological Relationships, Boanerges Aleman-Meza, I. Budak Arpinar, Mustafa V. Nural, Amit P. Sheth

Kno.e.sis Publications

Although arguable success of today’s keyword based search engines in certain information retrieval tasks, ranking search results in a meaningful way remains an open problem. In this work, the goal is to use of semantic relationships for ranking documents without relying on the existence of any specific structure in a document or links between documents. Instead, real-world entities are identified and the relevance of documents is determined using relationships that are known to exist between the entities in a populated ontology. We introduce a measure of relevance that is based on traversal and the semantics of relationships that link entities …

Go to article

First Prev Next Last