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

Physical Sciences and Mathematics Commons™

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

Discipline
Institution
Keyword
Publication Year
Publication
Publication Type
File Type

Articles 137821 - 137850 of 303928

Full-Text Articles in Physical Sciences and Mathematics

Generation Of A Complete Set Of Additive Shape-Invariant Potentials From An Euler Equation, Jonathan Bougie, Asim Gangopadhyaya, Jeffrey Mallow Dec 2015

Generation Of A Complete Set Of Additive Shape-Invariant Potentials From An Euler Equation, Jonathan Bougie, Asim Gangopadhyaya, Jeffrey Mallow

Asim Gangopadhyaya

In supersymmetric quantum mechanics, shape invariance is a sufficient condition for solvability. We show that all conventional additive shape-invariant superpotentials that are independent of ħ can be generated from two partial differential equations. One of these is equivalent to the one-dimensional Euler equation expressing momentum conservation for inviscid fluid flow, and it is closed by the other. We solve these equations, generate the set of all conventional shape-invariant superpotentials, and show that there are no others in this category. We then develop an algorithm for generating all additive shape-invariant superpotentials including those that depend on ħ explicitly.

Go to article

Supersymmetry And The Tunneling Problem In An Asymmetric Double Well, Asim Gangopadhyaya, Prasanta Panigrahi, Uday Sukhatne Dec 2015

Supersymmetry And The Tunneling Problem In An Asymmetric Double Well, Asim Gangopadhyaya, Prasanta Panigrahi, Uday Sukhatne

Asim Gangopadhyaya

The techniques of supersymmetric quantum mechanics are applied to the calculation of the energy difference between the ground state and the first excited state of an asymmetric double well. This splitting, originating from the tunneling effect, is computed via a systematic, rapidly converging perturbation expansion. Perturbative calculations to any order can be easily carried out using a logarithmic perturbation theory. Our approach yield substantially better results than alternative widely used semiclassical analyses.

Go to article

Mechanism Of Redox- And Co-Sensing By The Heme Protein, Cooa: Cryoradiolysis Studies, Robert Clark, Deanna Kalafut Dec 2015

Mechanism Of Redox- And Co-Sensing By The Heme Protein, Cooa: Cryoradiolysis Studies, Robert Clark, Deanna Kalafut

Robert Clark

Gas-sensing heme proteins participate in a variety of signal-transduction mechanisms across a broad range of biological systems. This class of proteins functions by undergoing an allosteric conformational change in response to the binding of a small gas molecule to a heme group. CooA, which is a redox- and CO-sensing transcription factor that is found in several bacteria, regulates gene expression that enables growth on CO as a sole energy source. In the current study, we have employed the technique of gamma-irradiation / cryoreduction spectroscopy (cryoradiolysis) to investigate facile changes that occur to the heme coordination structure of CooA during activation. …

Go to article

Holocene Climatic Change And Past Irish Societal Response, David Brown, M. Baillie, J. Palmer, Christian Turney Dec 2015

Holocene Climatic Change And Past Irish Societal Response, David Brown, M. Baillie, J. Palmer, Christian Turney

David C. Brown

No abstract provided.

Go to article

Discovering A Research Agenda For Using Design Rationale In Software Maintenance, Janet Burge, David Brown Dec 2015

Discovering A Research Agenda For Using Design Rationale In Software Maintenance, Janet Burge, David Brown

David C. Brown

Design Rationale consists of the reasons behind decisions made while designing. This information would be particularly useful during software maintenance. In this paper, we describe a study performed to investigate the content, structure, and use of design rationale during maintenance. The major goal of this study was to discover an agenda for further research into the use of design rationale for software maintenance.

Go to article

Measuring The Performance Gains From Directional Antennas In An Unplanned 802.11b Mesh Network, Jason Wilson, Patrick Gemme, Emmanuel Agu Dec 2015

Measuring The Performance Gains From Directional Antennas In An Unplanned 802.11b Mesh Network, Jason Wilson, Patrick Gemme, Emmanuel Agu

Emmanuel O. Agu

Wireless mesh networks are becoming increasingly popular. Most proposed mesh algorithms are evaluated using simulation. Simulations frequently oversimplify real world scenarios and can lead to results that are significantly different. Thus, although it is more difficult to run controlled experiments in already deployed real-world networks, it is important to understand how proposed improvements perform under these realistic scenarios. Several authors have suggested the use of directional antennas, but their merits have only comprehensively evaluated in simulators. Roofnet is an unplanned 802.11b wireless mesh network deployed by MIT and is constructed primarily of omni-directional antennas. We use measurements to evaluate performance …

Go to article

Inferring Unobservable Learning Variables From Students’ Help Seeking Behavior, Ivon Arroyo Dec 2015

Inferring Unobservable Learning Variables From Students’ Help Seeking Behavior, Ivon Arroyo

Ivon Arroyo

Results of an evaluation of students’ attitudes and their relationship to student behaviors within a tutoring system are presented. Starting from a correlation analysis that integrates survey-collected student attitudes, learning variables, and behaviors while using the tutor, we constructed a Bayesian Network that infers attitudes and perceptions towards help and the tutoring system.

Go to article

Coastal Resources Management Training Needs Assessment: Strategies And Opportunities, Kevin O'Brien, Claudette Robey, Wendy Kellogg, Michael Tevesz Dec 2015

Coastal Resources Management Training Needs Assessment: Strategies And Opportunities, Kevin O'Brien, Claudette Robey, Wendy Kellogg, Michael Tevesz

Michael J. Tevesz

The Old Woman Creek National Estuarine Research Reserve (OWC), Ohio Department of Natural Resources-Coastal Management Program (ODNRCMP), and Ohio Sea Grant College Program engaged the Great Lakes Environmental Finance Center (GLEFC) to aid them in developing a coastal resources management training initiative for Ohio coastal decision-makers. Coastal decision-maker professionals are expected to formulate effective strategies and apply interdisciplinary approaches to solving problems and policy issues that affect the environments of coastal regions. There are a number of professionals in a variety of occupations who make decisions regarding coastal and environmental policy issues. These individuals include those within the coastal resources …

Go to article

Silica-Bound Copper(Ii) Triazacyclononane As A Phosphate Esterase: Effect Of Linker Length And Surface Hydrophobicity, Brett Bodsgard, Robert Clark, Anthony Ehrbar, Judith Burstyn Dec 2015

Silica-Bound Copper(Ii) Triazacyclononane As A Phosphate Esterase: Effect Of Linker Length And Surface Hydrophobicity, Brett Bodsgard, Robert Clark, Anthony Ehrbar, Judith Burstyn

Robert Clark

A series of silica-bound Cu(II) triazacyclononane materials was prepared to study the effect of linker length and surface hydrophobicity on the hydrolysis of phosphate esters. The general synthetic approach for these heterogeneous reagents was rhodium-catalyzed hydrosilation between an alkenyl-modified triazacyclononane and hydride-modified silica followed by metallation with a Cu(II) salt. Elemental analysis confirmed that organic functionalization of the silica gel was successful and provided an estimate of the surface concentration of triazacyclononane. EPR spectra were consistent with square pyramidal Cu(II), indicating that Cu(II) ions were bound to the immobilized macrocycles. The hydrolytic efficacies of these heterogeneous reagents were tested with …

Go to article

Magnet Traveling Through A Conducting Pipe: A Variation On The Analytical Approach, Benjamin Irvine, Matthew Kemnetz, Asim Gangopadhyaya, Thomas Ruubel Dec 2015

Magnet Traveling Through A Conducting Pipe: A Variation On The Analytical Approach, Benjamin Irvine, Matthew Kemnetz, Asim Gangopadhyaya, Thomas Ruubel

Asim Gangopadhyaya

We present an analytical study of magnetic damping. In particular, we investigate the dynamics of a cylindrical neodymium magnet as it moves through a conducting tube. Owing to the very high degree of uniformity of the magnetization for neodymium magnets, we are able to provide completely analytical results for the electromotive force generated in the pipe and the consequent retarding force. Our analytical expressions are shown to have excellent agreement with experimental observations.

Go to article

Noncentral Potentials And Spherical Harmonics Using Supersymmetry And Shape Invariance, Ranabir Dutt, Asim Gangopadhyaya, Uday Sukhatne Dec 2015

Noncentral Potentials And Spherical Harmonics Using Supersymmetry And Shape Invariance, Ranabir Dutt, Asim Gangopadhyaya, Uday Sukhatne

Asim Gangopadhyaya

It is shown that the operator methods of supersymmetric quantum mechanics and the concept of shape invariance can profitably be used to derive properties of spherical harmonics in a simple way. The same operator techniques can also be applied to several problems with noncentral vector and scalar potentials. As examples, we analyze the bound state spectra of an electron in a Coulomb plus an Aharonov – Bohm field and/or in the magnetic field of a Dirac monopole.

Go to article

Isomer Distribution Of Succinylcyclohexenyl, Acetylcyclohexenyl And Acetylcyclopentenyl Enamines, A. Cook, Sarah Folk Dec 2015

Isomer Distribution Of Succinylcyclohexenyl, Acetylcyclohexenyl And Acetylcyclopentenyl Enamines, A. Cook, Sarah Folk

A. Gilbert Cook

The isomeric distributions of some cyclohexenyl enamines substituted by succinyl or acetyl groups at either the 2- or 6-positions are reported as are the isomeric distributions of similarly substituted cyclopentenyl enamines. Correlation between the C-13 NMR chemical shifts in these enamines and isomer distribution is shown. Density functional molecular modeling is used to demonstrate resonance and electrostatic effects on isomeric distributions.

Go to article

Mobile Mud Dynamics In The East China Sea Elucidated Using 210pb, 137cs, 7be, And 234th As Tracers, Jinlong Wang, Jinzhou Du, Mark Baskaran, Jing Zhang Dec 2015

Mobile Mud Dynamics In The East China Sea Elucidated Using 210pb, 137cs, 7be, And 234th As Tracers, Jinlong Wang, Jinzhou Du, Mark Baskaran, Jing Zhang

Environmental Science and Geology Faculty Research Publications

“Mobile mud” (MM), which has fine grain size distribution (>90% clay + silt, and <5% sand) and high porosity (≥0.50), plays an important role in the biogeochemical cycles in the estuarine areas and the inshore shelf. A suite of MM samples from the coastal area of the East China Sea (ECS) was collected in spring and summer of 2011 to observe their spatial and temporal distribution, grain size, and radionuclides concentrations. The MM thickness ranged from 0.5 to 11 cm (average: 2.2 cm (May) and 3.9 cm (August)). The thick mud layer is mainly distributed along the coast, with an area of 2.2 × 104 km2 in May and 1.5 × 104 km2 in August, with corresponding masses of 8.8 × 108 and 7.8 × 108 t, respectively. The estimated masses of MM are considerably larger than the annual sediment discharge mass of the Changjiang River. The distribution of 137Cs inventories in MM indicates that 137Cs can be effectively utilized as a transport tracer of MM in the river‐dominated estuaries and coastal areas. The higher inventories of 7Be in MM in the river mouth in spring are attributed to higher depositional flux and higher sediment discharge. The ratio of the MM inventory of 234Thex/production in the overlying water column of >2.5 in south inshore indicates that the sediment focusing resulted in the increased mass flux. The residence time of MM is estimated as 3–6 years both by mass balance of MM and 210Pbex in MM.

Go to article

Energy Subsidies And The Future Of Power, Christian Jewett Dec 2015

Energy Subsidies And The Future Of Power, Christian Jewett

Op-Eds from ENSC230 Energy and the Environment: Economics and Policies

The modern political climate has grown rife with talk concerning the use of fossil fuels as an energy source and how this may impact our planet for generations to come. The Left and the Right seem to be at odds over whether or not climate change is actually occurring, or who is causing it. Additionally, the energy industry likes to tout their “low-cost” energy sources as a boon to the global economy as well as a benefit to the consumer at large. However, are coal, oil, and natural gas truly the “cheapest” sources of energy? Whether or not one believes …

Go to article

Bipartite Probe Interval Graphs, Interval Point Bigraphs, And Circular Arcgraphs, David Brown, J. Lundgren Dec 2015

Bipartite Probe Interval Graphs, Interval Point Bigraphs, And Circular Arcgraphs, David Brown, J. Lundgren

David C. Brown

No abstract provided.

Go to article

Supersymmetric Quantum Mechanics And Solvable Models, Asim Gangopadhyaya, Jonathan Bougie, Jeffrey Mallow, C. Rasinariu Dec 2015

Supersymmetric Quantum Mechanics And Solvable Models, Asim Gangopadhyaya, Jonathan Bougie, Jeffrey Mallow, C. Rasinariu

Asim Gangopadhyaya

We review solvable models within the framework of supersymmetric quantum mechanics (SUSYQM). In SUSYQM, the shape invariance condition insures solvability of quantum mechanical problems. We review shape invariance and its connection to a consequent potential algebra. The additive shape invariance condition is specified by a difference-differential equation; we show that this equation is equivalent to an infinite set of partial differential equations. Solving these equations, we show that the known list of h-independent superpotentials is complete. We then describe how these equations could be extended to include superpotentials that do depend on h.

Go to article

Web-Based Intelligent Multimedia Tutoring For High Stakes Achievement Tests, Ivon Arroyo Dec 2015

Web-Based Intelligent Multimedia Tutoring For High Stakes Achievement Tests, Ivon Arroyo

Ivon Arroyo

We describe Wayang Outpost, a web-based ITS for the Math section of the Scholastic Aptitude Test (SAT). It has several distinctive features: help with multimedia animations and sound, problems embedded in narrative and fantasy contexts, alternative teaching strategies for students of different mental rotation abilities and memory retrieval speeds. Our work on adding intelligence for adaptivity is described. Evaluations prove that students learn with the tutor, but learning depends on the interaction of teaching strategies and cognitive abilities. A new adaptive tutor is being built based on evaluation results; surveys results and students’ log files analyses.

Go to article

Trends Analysis Of Coastal Training Programs In The National Estuarine Research Reserve System: Executive Summary, Claudette Robey, Kevin O'Brien, Kirstin Toth, Dan Baracksay, Michael Mcgoun, Wendy Kellogg, Michael Tevesz Dec 2015

Trends Analysis Of Coastal Training Programs In The National Estuarine Research Reserve System: Executive Summary, Claudette Robey, Kevin O'Brien, Kirstin Toth, Dan Baracksay, Michael Mcgoun, Wendy Kellogg, Michael Tevesz

Michael J. Tevesz

No abstract provided.

Go to article

Land-Use Pattern, Urbanization, And Deer–Vehicle Collisions In Alabama, Anwar Hussain, James Armstrong, David Brown, John Hogland Dec 2015

Land-Use Pattern, Urbanization, And Deer–Vehicle Collisions In Alabama, Anwar Hussain, James Armstrong, David Brown, John Hogland

David C. Brown

With the rise in deer–vehicle collisions across the United States, the associated costs also have risen. Increasingly, however, researchers are learning that these collisions are not a random phenomena but follow a systematic pattern. Building on this insight, we explored the role of county characteristics in influencing the pattern and incidence of white-tailed deer- (Odocoileus virginianus) related auto collisions. Using county level data from 1994 to 2003 in Alabama, we tested several data models with the above mentioned factors …

Go to article

Comment On "Ideal Capacitor Circuits And Energy Conservation" By K. Mita And M. Boufaida [Am. J. Phys. 67 (8), 737-739 (1999)], Asim Gangopadhyaya, Jeffrey Mallow Dec 2015

Comment On "Ideal Capacitor Circuits And Energy Conservation" By K. Mita And M. Boufaida [Am. J. Phys. 67 (8), 737-739 (1999)], Asim Gangopadhyaya, Jeffrey Mallow

Asim Gangopadhyaya

No abstract provided.

Go to article

Using Gis Network Analyst To Identify Suppliers For A Produce Co-Op In Waterville, Me, Bethany Darling, Jamie O'Connell Dec 2015

Using Gis Network Analyst To Identify Suppliers For A Produce Co-Op In Waterville, Me, Bethany Darling, Jamie O'Connell

Jamie O'Connell

No abstract provided.

Go to article

Impact Of Heme Reconstitution On The Spectroscopic Properties And Dna Binding Activity Of The H82a Variant Of The Carbon Monoxide-Sensing Heme Transcription Factor, Cooa, Rachel Troester, Robert Clark Dec 2015

Impact Of Heme Reconstitution On The Spectroscopic Properties And Dna Binding Activity Of The H82a Variant Of The Carbon Monoxide-Sensing Heme Transcription Factor, Cooa, Rachel Troester, Robert Clark

Robert Clark

CooA is a gas-sensing heme protein that regulates the expression of genes responsible for growth by carbon monoxide (CO) in several bacteria. CO binding to the CooA heme groups results in an allosteric conformation change that initiates the protein’s DNA binding function. All known CooA homologs have a conserved histidine residue that i) acts as the proximal heme ligand and ii) istrans to CO. Together with the results from mutagenesis studies, this observation suggests the presence of a proximal histidine ligand is required for CooA’s DNA-binding activity. However, since mutants lacking this His have been observed to lose heme …

Go to article

Semiclassical Approach To Quantum-Mechanical Problems With Broken Supersymmetry, Ranabir Dutt, Asim Gangopadhyaya, Avinash Khare, A. Pagnamenta, Uday Sukhatne Dec 2015

Semiclassical Approach To Quantum-Mechanical Problems With Broken Supersymmetry, Ranabir Dutt, Asim Gangopadhyaya, Avinash Khare, A. Pagnamenta, Uday Sukhatne

Asim Gangopadhyaya

The semiclassical WKB approximation method is reexamined in the context of nonrelativistic quantum-mechanical bound-state problems with broken supersymmetry (SUSY). This gives rise to an alternative quantization condition (denoted by BSWKB) which is different from the standard WKB formula and also different from the previously studied supersymmetric (SWKB) formula for unbroken SUSY. It is shown that to leading order in ħ, the BSWKB condition yields exact energy eigenvalues for shape-invariant potentials with broken SUSY (harmonic oscillator, Pöschl-Teller I and II) which are known to be analytically solvable. Further, we show explicitly that the higher-order corrections to these energy eigenvalues, up to …

Go to article

Reasoning With Design Rationale, Janet Burge, David Brown Dec 2015

Reasoning With Design Rationale, Janet Burge, David Brown

David C. Brown

Design Rationale (DR) consists of the decisions made during the design process and the reasons behind them. Because it offers more than just a “snapshot” of the final design decisions, DR is invaluable as an aid for revising, maintaining, documenting, evaluating, and learning the design. Much work has been performed on how DR can be captured and represented but not as much on how it can be used. In this paper, we investigate the use of DR by building InfoRat, a system that inferences over a design’s rationale in order to detect inconsistencies and to assess the impact of changes.

Go to article

Renormalization Group Equations In Broken Supersymmetric Theories Using Superspace Methods, Asim Gangopadhyaya, Darwin Chang Dec 2015

Renormalization Group Equations In Broken Supersymmetric Theories Using Superspace Methods, Asim Gangopadhyaya, Darwin Chang

Asim Gangopadhyaya

We apply the superfield method with the spurion technique to derive the renormalization-group equations in broken supersymmetric theories. We point out some possible ambiguities in this procedure and show that it is in general necessary to express the supersymmetry-breaking terms in explicit D-type form. We also found that it is possible to construct broken supersymmetric theories where some of the symmetry-breaking parameters do not receive any infinite renormalization.

Go to article

Tradeoffs Between Energy And Security In Wireless Networks, Fernando Colón Osorio, Emmanuel Agu, Kerry Mckay Dec 2015

Tradeoffs Between Energy And Security In Wireless Networks, Fernando Colón Osorio, Emmanuel Agu, Kerry Mckay

Emmanuel O. Agu

In recent years, several researchers have studied the vulnerabilities present in the encryption protocols and authentication mechanisms associated with 802.11-based networks. This research has led to the creation of protocol extensions and replacement proposals such as WPA, 802.11i, and 802.1X. In addition, Denial of Service attacks that can be launched against 802.11-based networks, with relative ease and impunity, have been studied. Simultaneously, researchers studying the limitations of wireless networks have turned their attention to one of the inherent limitation of wireless devices, namely, power consumption. Research in this area has been focused in understanding the impact of the network interface …

Go to article

Comment On ‘‘The Hidden Symmetry For A Quantum System With An Infinitely Deep Square-Well Potential By Shi-Hai Dong And Zhong-Qi Ma [Am. J. Phys. 70 (5) 520-521 (2002)], Asim Gangopadhyaya, Jeffrey Mallow Dec 2015

Comment On ‘‘The Hidden Symmetry For A Quantum System With An Infinitely Deep Square-Well Potential By Shi-Hai Dong And Zhong-Qi Ma [Am. J. Phys. 70 (5) 520-521 (2002)], Asim Gangopadhyaya, Jeffrey Mallow

Asim Gangopadhyaya

No abstract provided.

Go to article

Gas-Binding Studies Of The Carbon Monoxide Sensor, Cooa, Joshua Wagoner, Lindsey Dillingham, Robert Clark Dec 2015

Gas-Binding Studies Of The Carbon Monoxide Sensor, Cooa, Joshua Wagoner, Lindsey Dillingham, Robert Clark

Robert Clark

CooA is a carbon monoxide-sensing (CO-sensing) heme protein transcription factor that regulates gene activation in several bacteria and is a convenient model for studying analogous proteins in the human body. The goal of this study is to understand the specificity and mechanism of gas binding of CooA. To accomplish this, wild type CooA and selected protein variants were purified and then reacted with different diatomic gas molecules. The resulting species were characterized by UV-Visible and fluorescence spectroscopy.

Go to article

Preliminary Design Of A High Tc Superconducting Persistent Mode Current Switch, Christopher Hawley, Dominic Cuiuri, Steve Gower Dec 2015

Preliminary Design Of A High Tc Superconducting Persistent Mode Current Switch, Christopher Hawley, Dominic Cuiuri, Steve Gower

Dominic Cuiuri

Persistent Mode Current Switches (PMCS) are made from coils of superconductor that in theory will provide zero conduction losses when closed. By causing a section of the superconductor to leave its superconducting state and become resistive, the switch is effectively opened. There are currently 3 methods to open a PMCS; 1) applying heat, 2) applying a magnetic field or 3) application of current above the critical current (Ic) of the tape. The first two methods are not suitable for power applications as the switching time is too slow. Recent work at the University of Wollongong and in literature has shown …

Go to article

Characterizing The Performance And Behaviors Of Runners Using Twitter, Qian He, Emmanuel Agu, Diane Strong, Bengisu Tulu, Peder Pedersen Dec 2015

Characterizing The Performance And Behaviors Of Runners Using Twitter, Qian He, Emmanuel Agu, Diane Strong, Bengisu Tulu, Peder Pedersen

Emmanuel O. Agu

Running is a popular physical activity that improves physical and mental wellbeing. Unfortunately, up-to- date information about runners’ performance and psychological wellbeing is limited. Many questions remain unanswered, such as how far and how fast runners typically run, their preferred running times and frequencies, how long new runners persist before dropping out, and what factors cause runners to quit. Without hard data, establishing patterns of runner behavior and mitigating the challenges they face are difficult. Collecting data manually from large numbers of runners for research studies is costly and time consuming. Emerging Social Networking Services (SNS) and fitness tracking devices …

Go to article

First Prev Next Last