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

Physical Sciences and Mathematics Commons

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

2015

Discipline
Institution
Keyword
Publication
Publication Type
File Type

Articles 2491 - 2520 of 12617

Full-Text Articles in Physical Sciences and Mathematics

U.S. Drought Monitor, September 8, 2015, Richard Tinker Sep 2015

U.S. Drought Monitor, September 8, 2015, Richard Tinker

United States Agricultural Commodities in Drought Archive

Drought map of U.S. for September 8, 2015 (9/8/15) plus: U.S. crop areas experiencing drought (map), Approximate percentage of crop located in drought, by state (bar graph), Percent of crop area located in drought, past 52 weeks (line graph) for: Corn, Soybeans, Hay, Cattle, Winter wheat.


On Partial Identification Of The Pure Direct Effect, Caleb Miles, Phyllis Kanki, Seema Meloni, Eric Tchetgen Tchetgen Sep 2015

On Partial Identification Of The Pure Direct Effect, Caleb Miles, Phyllis Kanki, Seema Meloni, Eric Tchetgen Tchetgen

Harvard University Biostatistics Working Paper Series

No abstract provided.


Ultraviolet Luminosity Density Of The Universe During The Epoch Of Reionization, Ketron Mitchell-Wynne, Asantha Cooray, Yan Gong, Matthew Ashby, Timothy Dolch, Henry Ferguson, Steven Finkelstein, Norman Grogin, Dale D. Kocevski, Anton Koekemoer, Joel Primack, Joseph Smidt Sep 2015

Ultraviolet Luminosity Density Of The Universe During The Epoch Of Reionization, Ketron Mitchell-Wynne, Asantha Cooray, Yan Gong, Matthew Ashby, Timothy Dolch, Henry Ferguson, Steven Finkelstein, Norman Grogin, Dale D. Kocevski, Anton Koekemoer, Joel Primack, Joseph Smidt

Physics and Astronomy Faculty Publications

The spatial fluctuations of the extragalactic background light trace the total emission from all stars and galaxies in the Universe. A multiwavelength study can be used to measure the integrated emission from first galaxies during reionization when the Universe was about 500 million years old. Here we report arcmin-scale spatial fluctuations in one of the deepest sky surveys with the Hubble Space Telescope in five wavebands between 0.6 and 1.6 μm. We model-fit the angular power spectra of intensity fluctuation measurements to find the ultraviolet luminosity density of galaxies at redshifts greater than 8 to be log ρUV = …


Simultaneous Stress And Field Control Of Sustainable Switching Of Ferroelectric Phases, P. Finkel, M. Staruch, A. Amin, M. Ahart, Samuel E. Lofland Sep 2015

Simultaneous Stress And Field Control Of Sustainable Switching Of Ferroelectric Phases, P. Finkel, M. Staruch, A. Amin, M. Ahart, Samuel E. Lofland

College of Science & Mathematics Departmental Research

In ferroelectrics, manifestation of a strong electromechanical coupling is attributed to both engineered domain morphology and phase transformations. However, realization of large sustainable and reversible strains and polarization rotation has been limited by fatigue, nonlinearity and hysteresis losses. Here, we demonstrate that large strain and polarization rotation can be generated for over 40 × 106 cycles with little fatigue by realization of a reversible ferroelectric-ferroelectric phase transition in [011] cut Pb(In1/2Nb1/2)O3-Pb(Mg1/3Nb2/3)O3-PbTiO3 (PIN-PMN-PT) relaxor ferroelectric single crystal. Direct tuning of this effect through combination of stress and applied electric field, confirmed both macroscopically and microscopically with x-ray and Raman scattering, reveals …


Secondary Electrohydrodynamic Flow Generated By Corona And Dielectric Barrier Discharges, Mohammadreza Ghazanchaei Sep 2015

Secondary Electrohydrodynamic Flow Generated By Corona And Dielectric Barrier Discharges, Mohammadreza Ghazanchaei

Electronic Thesis and Dissertation Repository

One of the main goals of applied electrostatics engineering is to discover new perspectives in a wide range of research areas. Controlling the fluid media through electrostatic forces has brought new important scientific and industrial applications. Electric field induced flows, or electrohydrodynamics (EHD), have shown promise in the field of fluid dynamics. Although numerous EHD applications have been explored and extensively studied so far, most of the works are either experimental studies, which are not capable to explain the in depth physics of the phenomena, or detailed analytical studies, which are not time effective. The focus of this study is …


Cognitive Activity Support Tools: Design Of The Visual Interface, Paul Parsons Sep 2015

Cognitive Activity Support Tools: Design Of The Visual Interface, Paul Parsons

Paul Parsons

This dissertation is broadly concerned with interactive computational tools that support the performance of complex cognitive activities, examples of which are analytical reasoning, decision making, problem solving, sense making, forecasting, and learning. Examples of tools that support such activities are visualization-based tools in the areas of: education, information visualization, personal information management, statistics, and health informatics. Such tools enable access to information and data and, through interaction, enable a human-information discourse. In a more specific sense, this dissertation is concerned with the design of the visual interface of these tools. This dissertation presents a large and comprehensive theoretical framework to …


Preparing Computer Science Graduates For The 21st Century, Paul Parsons Sep 2015

Preparing Computer Science Graduates For The 21st Century, Paul Parsons

Paul Parsons

The nature of computer use has changed remarkably in the past fifty years. However, most undergraduate computer science courses are still often taught through an old paradigm that is not adequate to address modern concerns. This 90 minute seminar will address some issues relevant to preparing computer scientists for the 21st century. These include issues central to human-computer interaction (HCI) such as cognitive and perceptual aspects of computer users, ergonomics, and human factors. Although there has been literature on this topic for at least the past 15 years, it is still not widely recognized nor understood by the majority of …


Contribution Of Raman Scattering To Polarized Radiation Field In Ocean Waters, Peng Wang Zhai, Yongxiang Hu, David M. Winker, Bryan A. Franz, Emmanuel Boss Sep 2015

Contribution Of Raman Scattering To Polarized Radiation Field In Ocean Waters, Peng Wang Zhai, Yongxiang Hu, David M. Winker, Bryan A. Franz, Emmanuel Boss

Marine Sciences Faculty Scholarship

We have implemented Raman scattering in a vector radiative transfer model for coupled atmosphere and ocean systems. A sensitivity study shows that the Raman scattering contribution is greatest in clear waters and at longer wavelengths. The Raman scattering contribution may surpass the elastic scattering contribution by several orders of magnitude at depth. The degree of linear polarization in water is smaller when Raman scattering is included. The orientation of the polarization ellipse shows similar patterns for both elastic and inelastic scattering contributions. As polarimeters and multipolarization-state lidars are planned for future Earth observing missions, our model can serve as a …


Quantitative Analysis Of The Density Of Trap States At The Semiconductor-Dielectric Interface In Organic Field-Effect Transistors, Peter J. Diemer, Zachary A. Lamport, Yaochuan Mei, Jeremy W. Ward, Katelyn P. Goetz, Wei Li, Marcia M. Payne, Martin Guthold, John E. Anthony, Oana D. Jurchescu Sep 2015

Quantitative Analysis Of The Density Of Trap States At The Semiconductor-Dielectric Interface In Organic Field-Effect Transistors, Peter J. Diemer, Zachary A. Lamport, Yaochuan Mei, Jeremy W. Ward, Katelyn P. Goetz, Wei Li, Marcia M. Payne, Martin Guthold, John E. Anthony, Oana D. Jurchescu

Chemistry Faculty Publications

The electrical properties of organic field-effect transistors are governed by the quality of the constituting layers, and the resulting interfaces. We compare the properties of the same organic semiconductor film, 2,8-difluoro- 5,11-bis (triethylsilylethynyl) anthradithiophene, with bottom SiO2 dielectric and top Cytop dielectric and find a 10× increase in charge carrier mobility, from 0.17 ± 0.19 cm2 V−1 s−1 to 1.5 ± 0.70 cm2 V−1 s−1, when the polymer dielectric is used. This results from a significant reduction of the trap density of states in the semiconductor band-gap, and a decrease in the …


Enzyme Localization, Crowding, And Buffers Collectively Modulate Diffusion-Influenced Signal Transduction: Insights From Continuum Diffusion Modeling, Peter M. Kekenes-Huskey, Changsun Eun, J. A. Mccammon Sep 2015

Enzyme Localization, Crowding, And Buffers Collectively Modulate Diffusion-Influenced Signal Transduction: Insights From Continuum Diffusion Modeling, Peter M. Kekenes-Huskey, Changsun Eun, J. A. Mccammon

Chemistry Faculty Publications

Biochemical reaction networks consisting of coupled enzymes connect substrate signaling events with biological function. Substrates involved in these reactions can be strongly influenced by diffusion “barriers” arising from impenetrable cellular structures and macromolecules, as well as interactions with biomolecules, especially within crowded environments. For diffusion-influenced reactions, the spatial organization of diffusion barriers arising from intracellular structures, non-specific crowders, and specific-binders (buffers) strongly controls the temporal and spatial reaction kinetics. In this study, we use two prototypical biochemical reactions, a Goodwin oscillator, and a reaction with a periodic source/sink term to examine how a diffusion barrier that partitions substrates controls reaction …


Effect Of Quercetin, Genistein And Kaempferol On Glutathione And Glutathione-Redox Cycle Enzymes In 3t3-L1 Preadipocytes, William Y. Boadi, Paul K. Amartey, Andrew Lo Sep 2015

Effect Of Quercetin, Genistein And Kaempferol On Glutathione And Glutathione-Redox Cycle Enzymes In 3t3-L1 Preadipocytes, William Y. Boadi, Paul K. Amartey, Andrew Lo

Chemistry Faculty Research

Context and objective: Many studies have shown that cellular redox potential is largely determined by glutathione (GSH), which accounts for more than 90% of cellular nonprotein thiols. The aim of this study was to delineate the effect of three flavonoids – namely, quercetin, kaempferol and genistein – and exogenous GSH on oxidative damage by the Fenton’s pathway through the GSH and GSH-redox cycle enzymes in 3T3-L1 cells. Materials and methods: 3T3-L1 preadipocytes were exposed to each flavonoid and GSH at concentrations of 0, 5, 10, 15, 20 and 25 µM and then GSH levels and activities of glutathione peroxidase (GSH-Px), …


Controls On Suspended Particle Properties And Water Clarity Along A Partially-Mixed Estuary, York River, Virginia, Usa, K. A. Fall, C. T. Friedrichs, G. M. Cartwright, D. G. Bowers Sep 2015

Controls On Suspended Particle Properties And Water Clarity Along A Partially-Mixed Estuary, York River, Virginia, Usa, K. A. Fall, C. T. Friedrichs, G. M. Cartwright, D. G. Bowers

Presentations

The Chesapeake Bay and its associated tidal tributaries, which together form one of the United States’ largest and most important estuaries, are among the many coastal systems where degraded water clarity is a major concern. Despite long-term decreases in sediment input, water clarity over the last 20 years has continued to deteriorate in the Bay and its tributaries (Williams et al., 2010). Analysis of long-term monitoring data (Wang et al., 2010) found that the concentration of total suspended solids (TSS), the regulatory indicator of ‘suspended sediment pollution’, is about as likely to be positively or negatively correlated to sediment loads …


Identification Of Suspended Resilient Pellets In Particles Tracked By A Particle Image Camera System (Pics) In A Muddy Estuary, Grace M. Cartwright, Kelsey A. Fall, Carl T. Friedrichs Sep 2015

Identification Of Suspended Resilient Pellets In Particles Tracked By A Particle Image Camera System (Pics) In A Muddy Estuary, Grace M. Cartwright, Kelsey A. Fall, Carl T. Friedrichs

Presentations

The Particle Imaging Camera System (PICS) was designed to allow for the measurement of the settling velocity of individual particles in situ by using the smaller particles (< density < 1800kg/m3 ). This classification system, while adequate for suspended dredge plumes, needs to be revisited when the PICS is used in a muddy estuary, such as the York River Estuary, Virginia. Figure 1B shows the settling velocities of particles tracked within a video captured 2.5m from the surface in the Clay Bank region of the York River, plotted against their equivalent spherical diameters. While most of the particles are classified as flocs, as indicated by the blue dots in Figure 1C and the peak in the relative number of particles in Figure 1E, there is still a large number of particles classified as “bed aggregates” (red dots). This number of higher density particles may be unexpected, as this video was captured 4.25m over a “muddy bed” in a natural system with a flood current of 40cm/s. However, biologically compacted mud in the form of resilient pellets (see Figure 2) may be the answer. Bed sediments from five sediment cruises during this study period (Aug 2012 – Nov 2014) were found to be comprised of 86-96% mud (Figure 3A). However, 9-14% of the mud was packaged as resilient pellets (Figure 3B). Sediment captured 38cm above the bed by traps deployed on tripods were found to have 92-98% mud, with 4-14% of the mud packaged as resilient pellets (Figures 3A and B). Pellets isolated from the Apr to Jul 2014 trap were sampled with the PICS to determine the distribution of settling velocities (Ws), particle densities, and the ratio of the long and short axis of the particles. This will be used to identify the pellets in PICS videos captured during the five 6h anchor stations (black lines in Figure 3) where three depths were sampled each hour.


Controls On Bed Erodibility In A Muddy, Partially-Mixed Estuary: York River, Virginia, Usa, Carl T. Friedrichs, Grace M. Cartwright, Patrick J. Dickhut, Kelsey A. Fall Sep 2015

Controls On Bed Erodibility In A Muddy, Partially-Mixed Estuary: York River, Virginia, Usa, Carl T. Friedrichs, Grace M. Cartwright, Patrick J. Dickhut, Kelsey A. Fall

Presentations

Appropriate parameterization of time-dependent erodibility of muddy seabeds is a significant barrier to improved understanding and accurate modelling of sediment dynamics in estuaries and other coastal regions. In an effort to better understand controls on muddy seabed erodibility, bed erodibility and associated bed sediment properties have been measured by our group on cores collected on dozens of cruises over the last decade in the York Estuary (e.g., Dickhudt et al., 2009, 2011; Kraatz, 2013). We have also inferred time-varying erodibility indirectly in the York Estuary over several years by vertically integrating observations of tidally-varying suspended sediment concentration (e.g. Friedrichs et …


Eletron-Helium Laser-Assisted Free-Free Scattering For Incident Energies From 30 - 200 Ev: Effects Of Polarization Direction, B. A. Deharak, Benjamin Nosarzewski, Mahsa Siavashpouri, Nicholas L. S. Martin Sep 2015

Eletron-Helium Laser-Assisted Free-Free Scattering For Incident Energies From 30 - 200 Ev: Effects Of Polarization Direction, B. A. Deharak, Benjamin Nosarzewski, Mahsa Siavashpouri, Nicholas L. S. Martin

Physics and Astronomy Faculty Publications

We report on experiments that examine electron-helium scattering in the presence of an Nd:YAG laser field of 1.17 eV photons. At each incidentelectron energy (30, 60, and 200 eV), the laser polarization direction is varied within a plane perpendicular to the Watson approximation calculations.


Experimentally Generating Any Desired Partially Coherent Schell-Model Source Using Phase-Only Control, Milo W. Hyde Iv, Santasri Basu, David G. Voelz, Xifeng Xiao Sep 2015

Experimentally Generating Any Desired Partially Coherent Schell-Model Source Using Phase-Only Control, Milo W. Hyde Iv, Santasri Basu, David G. Voelz, Xifeng Xiao

Faculty Publications

A technique is presented to produce any desired partially coherent Schell-model source using a single phase-only liquid-crystal spatial light modulator (SLM). Existing methods use SLMs in combination with amplitude filters to manipulate the phase and amplitude of an initially coherent source. The technique presented here controls both the phase and amplitude using a single SLM, thereby making the amplitude filters unnecessary. This simplifies the optical setup and significantly increases the utility and flexibility of the resulting system. The analytical development of the technique is presented and discussed. To validate the proposed approach, experimental results of three partially coherent Schell-model sources …


Efficient Photochemical Synthesis Of Peptide-Α-Phenylthioesters, Andrew Pardo, Tyrone J. Hogenauer, Zhefeng Cai, Julian A. Vellucci, Efrain M. Castillo, Carl W. Dirk, Andreas H. Franz, Katja Michael Sep 2015

Efficient Photochemical Synthesis Of Peptide-Α-Phenylthioesters, Andrew Pardo, Tyrone J. Hogenauer, Zhefeng Cai, Julian A. Vellucci, Efrain M. Castillo, Carl W. Dirk, Andreas H. Franz, Katja Michael

College of the Pacific Faculty Articles

Low yields and substantial epimerization of peptide-α-thioesters often compromise the overall efficiency of native chemical ligation (NCL). Peptide arylthioesters are more reactive than peptide alkylthioesters in NCL, but are also more difficult to handle due to their propensity to hydrolyze, and are therefore often generated in situ. However, pre-prepared peptide arylthioesters are required for some NCL applications. Here we present a 7-nitroindoline-based photochemical method that generates protected peptide phenylthioesters under neutral reaction conditions via their activated esters from photoreactive peptide precursors in high isolated yields, and with low levels of epimerization. This method is fully compatible with Fmoc-strategy solid-phase peptide …


Clinical Data Warehousing: A Business Analytics Approach For Managing Health Data, Lekha Narra, Tony Sahama, Peta Stapleton Sep 2015

Clinical Data Warehousing: A Business Analytics Approach For Managing Health Data, Lekha Narra, Tony Sahama, Peta Stapleton

Peta B. Stapleton

Heterogeneous health data is a critical issue when managing health information for quality decision making processes. In this paper we examine the efficient aggregation of lifestyle information through a data warehousing architecture lens. We present a proof of concept for a clinical data warehouse architecture that enables evidence based decision making processes by integrating and organising disparate data silos in support of healthcare services improvement paradigms.


Work Integrated Learning In Stem In Australian Universities: Final Report: Submitted To The Office Of The Chief Scientist, Daniel Edwards, Kate Perkins, Jacob Pearce, Jennifer Hong Sep 2015

Work Integrated Learning In Stem In Australian Universities: Final Report: Submitted To The Office Of The Chief Scientist, Daniel Edwards, Kate Perkins, Jacob Pearce, Jennifer Hong

Dr Daniel Edwards

The Australian Council for Educational Research (ACER) undertook this study for the Office of the Chief Scientist (OCS). It explores the practice and application of Work Integrated Learning (WIL) in STEM, with a particular focus on natural and physical sciences, information technology, and agriculture departments in Australian universities. The project involved a detailed ‘stocktake’ of WIL in practice in these disciplines, with collection of information by interview, survey instruments, consultation with stakeholders and literature reviews. Every university in Australia was visited as part of this project, with interviews and consultation sessions gathering insight from more than 120 academics and support …


Work Integrated Learning In Stem In Australian Universities: Final Report: Submitted To The Office Of The Chief Scientist, Daniel Edwards, Kate Perkins, Jacob Pearce, Jennifer Hong Sep 2015

Work Integrated Learning In Stem In Australian Universities: Final Report: Submitted To The Office Of The Chief Scientist, Daniel Edwards, Kate Perkins, Jacob Pearce, Jennifer Hong

Dr Jacob Pearce

The Australian Council for Educational Research (ACER) undertook this study for the Office of the Chief Scientist (OCS). It explores the practice and application of Work Integrated Learning (WIL) in STEM, with a particular focus on natural and physical sciences, information technology, and agriculture departments in Australian universities. The project involved a detailed ‘stocktake’ of WIL in practice in these disciplines, with collection of information by interview, survey instruments, consultation with stakeholders and literature reviews. Every university in Australia was visited as part of this project, with interviews and consultation sessions gathering insight from more than 120 academics and support …


The Impact Of Climate Change On Select Ecosystems, Mary Snow, Richard Snow Sep 2015

The Impact Of Climate Change On Select Ecosystems, Mary Snow, Richard Snow

Publications

Terrestrial and marine environments are experiencing pronounced changes. As species and their ecosystems undergo rising temperatures, varying precipitation patterns and alterations in their chemistry and phenology, there is a great deal of added stress on many organisms. Many species attempting to adapt to a rapidly changing climate are forced to migrate or to become extinct. Forest communities are changing in composition as well as migrating northward. Often, roads, cities, and other forms of development physically impede migration. Some species are not able to migrate at the pace with which their ecosystems are warming. In some forest communities, southern boundaries are …


Application Of An Education Research Lab (Erl) Model To A Community Sailing Program, Lauren Shure, Emilie Ney, Precious Broffee, Gerene K. Starratt, Andy Roberts Sep 2015

Application Of An Education Research Lab (Erl) Model To A Community Sailing Program, Lauren Shure, Emilie Ney, Precious Broffee, Gerene K. Starratt, Andy Roberts

South Florida Education Research Conference

This presentation showcases the application of a university-based education research lab (ERL) model to the evaluation of a community sailing program for individuals with disabilities. Presenters conceptualize the ERL model as a mutually beneficial relationship between universities and community education agencies.


Unseen Minutia, Sara Kapadia Sep 2015

Unseen Minutia, Sara Kapadia

The STEAM Journal

A brief thought on the unseen details.


Art, Math, And Physics; All About For, Chris Brownell, Steve Pauls Sep 2015

Art, Math, And Physics; All About For, Chris Brownell, Steve Pauls

The STEAM Journal

Anish Kapoor’s public sculpture “Cloud Gate” and Frame of Reference.


Relationships, Michael Goodman Sep 2015

Relationships, Michael Goodman

The STEAM Journal

No abstract provided.


The Threshold Of Hearing, Mike Wereski Sep 2015

The Threshold Of Hearing, Mike Wereski

The STEAM Journal

No abstract provided.


Ecoscience + Art Initiative: Designing A New Paradigm For College Education, Scholarship, And Service, Changwoo Ahn Sep 2015

Ecoscience + Art Initiative: Designing A New Paradigm For College Education, Scholarship, And Service, Changwoo Ahn

The STEAM Journal

The paper presents a new initiative, EcoScience + Art, which blooms at George Mason University. The creator explains the background, history, and recent activities of the initiative, and also introduces an on-going special project called “The Rain Project”, a student participatory project to design, construct, and monitor a green infrastructure (i.e., floating wetland) for sustainable stormwater management on campus. The special project is geared to design and present a new paradigm to integrate college education, scholarship, and service. The relevance of the initiative and the special project to STEAM education is discussed.


Putting The Team In Steam: The Art Of Robot Making, Teresa Walker, David Thompson Sep 2015

Putting The Team In Steam: The Art Of Robot Making, Teresa Walker, David Thompson

The STEAM Journal

What began as a life partnership has evolved into an early learning STEAM team. Artist, David Thompson, uses science, technology, engineering and math, on a daily basis, to create robots and much more. Teresa Day Walker is an assistant professor of early childhood education. Through necessity they discovered their combined talents could be used to promote STEAM in early childhood. David and Teri teamed up to provide a nearly impromptu robot making demonstration for 100 kindergarten students. After reading their co-authored book, Robot Hide and Seek, both, clay based and 3-D modeled images were used to generate interest and …


Improvement Of Mechanical Properties And Water Stability Of Vegetable Protein Based Plastics, Gowrishankar Srinivasan Sep 2015

Improvement Of Mechanical Properties And Water Stability Of Vegetable Protein Based Plastics, Gowrishankar Srinivasan

Gowrishankar Srinivasan

Bio-renewable bio-degradable plastics are a potential solution to the growing problems of pollution caused by petroleum plastics and dependency on foreign nations for petroleum resources. One possible feed stock for these materials are vegetable proteins, especially from soy bean and corn. These proteins have relatively high molecular weights and have the potential of being processed with standard polymer processing technologies. But some issues that need to be addressed are their water instability (soy protein) and inferior mechanical properties as compared to petroleum derived plastics. In this study, soy protein isolates (SPI) and zein protein was processed with various additives and …


Ambiguity In Speaking Chemistry And Other Stem Content: Educational Implications, Mick D. Isaacson, Michelle Michaels Sep 2015

Ambiguity In Speaking Chemistry And Other Stem Content: Educational Implications, Mick D. Isaacson, Michelle Michaels

Journal of Science Education for Students with Disabilities

Ambiguity in speech is a possible barrier to the acquisition of knowledge for students who have print disabilities (such as blindness, visual impairments, and some specific learning disabilities) and rely on auditory input for learning. Chemistry appears to have considerable potential for being spoken ambiguously and may be a barrier to accessing knowledge and to learning. Educators in chemistry may be unaware of, or have limited awareness of, potential ambiguity in speaking chemistry and may speak chemistry ambiguously to their students. One purpose of this paper is to increase awareness of potential ambiguity in speaking chemistry and other STEM fields …