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2012

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Full-Text Articles in Physical Sciences and Mathematics

Nextgen Flight Deck Data Comm: Auxiliary Synthetic Speech Phase I, Tracy Lennertz, Judith Bürki-Cohen, Andrea L. Sparko, Nickolas D. Macchiarella, Jason Kring, Mike Coman, Tom Haritos, Jeffry Alvarado Dec 2012

Nextgen Flight Deck Data Comm: Auxiliary Synthetic Speech Phase I, Tracy Lennertz, Judith Bürki-Cohen, Andrea L. Sparko, Nickolas D. Macchiarella, Jason Kring, Mike Coman, Tom Haritos, Jeffry Alvarado

Publications

Data Comm—a text-based controller-pilot communication system—is critical to many NextGen improvements. With Data Comm, communication becomes a visual task. Interacting with a visual Data Comm display may yield an unsafe increase in head-down time, particularly for single-pilot operations. This study examined the feasibility of supplementing Data Comm with synthetic speech. To this end, thirty-two pilots flew two experimental scenarios in a Cessna 172 Flight Training Device. In one scenario, ATC communication was with a text-only Data Comm display, in the other, communication was with a text Data Comm display with synthetic speech that read aloud each message (i ...


Histological Changes In The Target Organs Of Channa Punctatus After Exposure To Anthraquinone Vat Dyes, Rajee Olaganathan, Jamila Patterson Dec 2012

Histological Changes In The Target Organs Of Channa Punctatus After Exposure To Anthraquinone Vat Dyes, Rajee Olaganathan, Jamila Patterson

Publications

The present study is an attempt on histopathology of gill, liver, kidney and intestine of Channa punctatus after exposure to sublethal concentrations of anthraquinone vat dyes viz., vat blue 4 and vat green 1. The dyes has been found to produce several damages in the vital organs of C. punctatus leading to various lesions like extensive lamellar hypertrophy with some proliferation at the base of secondary lamellae and hyperplasia of intercellular epithelial cells in the gill; fat accumulation, hepatic necrosis, aggregation of polymorphonuclear leucocytes, hepatocellular degeneration and aggregation of hepatocytes in liver; while in kidney it caused hyperplastic of the ...


Testing The Predictive Performance Of Distribution Models, Volker Bahn, Brian Mcgill Dec 2012

Testing The Predictive Performance Of Distribution Models, Volker Bahn, Brian Mcgill

Publications

Distribution models are used to predict the likelihood of occurrence or abundance of a species at locations where census data are not available. An integral part of modelling is the testing of model performance. We compared different schemes and measures for testing model performance using 79 species from the North American Breeding Bird Survey. The four testing schemes we compared featured increasing independence between test and training data: resubstitution, random data hold-out and two spatially segregated data hold-out designs. The different testing measures also addressed different levels of information content in the dependent variable: regression R2 for absolute abundance, squared ...


Protein Nano-Object Integrator (Pronoi) For Generating Atomic Style Objects For Molecular Modeling, Nicholas Smith, Brandon Campbell, Lin Li, Chuan Li, Emil Alexov Dec 2012

Protein Nano-Object Integrator (Pronoi) For Generating Atomic Style Objects For Molecular Modeling, Nicholas Smith, Brandon Campbell, Lin Li, Chuan Li, Emil Alexov

Publications

Background

With the progress of nanotechnology, one frequently has to model biological macromolecules simultaneously with nano-objects. However, the atomic structures of the nano objects are typically not available or they are solid state entities. Because of that, the researchers have to investigate such nano systems by generating models of the nano objects in a manner that the existing software be able to carry the simulations. In addition, it should allow generating composite objects with complex shape by combining basic geometrical figures and embedding biological macromolecules within the system.

Results

Here we report the Protein Nano-Object Integrator (ProNOI) which allows for ...


Multi-Color Observations Of Short Grb Afterglows: 20 Events Observed Between 2007 And 2010, A. Nicuesa Guelbenzu, S. Klose, J. Greiner, D. A. Kann, T. Krühler, A. Rossi, S. Schulze, P. M. J. Afonso, J. Elliott, R Filgas, Dieter H. Hartmann, A Kupcu Yoldas, S Mcbreen, M Nardini, F Olivares E., A Rau, S Schmidl, P Schady, V Sudilovsky, A C. Updike, A Yoldas Dec 2012

Multi-Color Observations Of Short Grb Afterglows: 20 Events Observed Between 2007 And 2010, A. Nicuesa Guelbenzu, S. Klose, J. Greiner, D. A. Kann, T. Krühler, A. Rossi, S. Schulze, P. M. J. Afonso, J. Elliott, R Filgas, Dieter H. Hartmann, A Kupcu Yoldas, S Mcbreen, M Nardini, F Olivares E., A Rau, S Schmidl, P Schady, V Sudilovsky, A C. Updike, A Yoldas

Publications

We report on follow-up observations of 20 short-duration gamma-ray bursts (GRBs; T90 <2 >s) performed in g'r'i'z' JHKs with the Gamma-Ray Burst Optical Near-Infrared Detector (GROND) between mid-2007 and the end of 2010. This is one of the most compre-hensive data sets on GRB afterglow observations of short bursts published so far. In three cases, GROND was on target within less than 10 min after the trigger, leading to the discovery of the afterglow of GRB 081226A and its faint underlying host galaxy. In addition, GROND was able to image the optical afterglow and follow the light curve ...


An Intense Traveling Airglow Front In The Upper Mesosphere–Lower Thermosphere With Characteristics Of A Bore Observed Over Alice Springs, Australia, During A Strong 2 Day Wave Episode, R. L. Walterscheid, J. H. Hecht, L. J. Galinas, Michael P. Hickey Ph.D., I. M. Reid Nov 2012

An Intense Traveling Airglow Front In The Upper Mesosphere–Lower Thermosphere With Characteristics Of A Bore Observed Over Alice Springs, Australia, During A Strong 2 Day Wave Episode, R. L. Walterscheid, J. H. Hecht, L. J. Galinas, Michael P. Hickey Ph.D., I. M. Reid

Publications

The Aerospace Corporation’s Nightglow Imager observed a large step function change in airglow in the form of a traveling front in the OH Meinel (OHM) and O2 atmospheric (O2A) airglow emissions over Alice Springs, Australia, on 2 February 2003. The front exhibited nearly a factor of 2 stepwise increase in the OHM brightness and a stepwise decrease in the O2A brightness. There was significant (~25 K) cooling behind the airglow fronts. The OHM airglow brightness behind the front was among the brightest for Alice Springs that we have measured in 7 years of observations. The event was associated with ...


Spectral Engineering Of Optical Fiber Preforms Through Active Nanoparticle Doping, T. Lindstrom, E. Garber, D. Edmonson, T. Hawkins, Y. Chen, G. Turri, M. Bass, J. Ballato Nov 2012

Spectral Engineering Of Optical Fiber Preforms Through Active Nanoparticle Doping, T. Lindstrom, E. Garber, D. Edmonson, T. Hawkins, Y. Chen, G. Turri, M. Bass, J. Ballato

Publications

Europium doped alkaline earth fluoride [Eu:AEF2 (AE = Ca, Sr, Ba)] nanoparticles were synthesized and systematically incorporated into the core of modified chemical vapor deposition (MCVD)-derived silica-based preforms by solution doping. The resulting preforms were examined to determine the impact of the nanoparticles chemistry on the spectroscopic behavior of the glass. The dominant existence of Eu3+ was demonstrated in all preforms, which is in contrast to conventional solution doped preforms employing dissolved europium salts where Eu2+ is primarily observed. Raman spectroscopy and fluorescence lifetime measurements indicated that the nanoparticles composition is effective in controlling, at a local chemical and ...


Radiation From Accelerated Particles In Relativistic Jets With Shocks, Shear-Flow, And Reconnection, K.-I. Nishikawa, P. Hardee, Y. Mizuno, I. Dutan, B. Zhang, M. Medvedev, E. J. Chor, K. W. Min, J. Niemiec, Y Mizuno, A Nordlund, J T. Frederiksen, H Sol, M Pohl, Dieter H. Hartmann Oct 2012

Radiation From Accelerated Particles In Relativistic Jets With Shocks, Shear-Flow, And Reconnection, K.-I. Nishikawa, P. Hardee, Y. Mizuno, I. Dutan, B. Zhang, M. Medvedev, E. J. Chor, K. W. Min, J. Niemiec, Y Mizuno, A Nordlund, J T. Frederiksen, H Sol, M Pohl, Dieter H. Hartmann

Publications

We have investigated particle acceleration and shock structure associated with an unmagnetized rel-ativistic jet propagating into an unmagnetized plasma for electron-positron and electron-ion plasmas. Strong magnetic fields generated in the trailing jet shock lead to transverse deflection and acceleration of the electrons. We have self-consistently calculated the radiation from the electrons accelerated in the turbulent magnetic fields for different jet Lorentz factors. We find that the synthetic spectra depend on the bulk Lorentz factor of the jet, the jet temperature, and the strength of the magnetic fields generated in the shock. We have investigated the generation of magnetic fields associated ...


Demographic Amplification Of Climate Change Experienced By The Contiguous United States Population During The 20th Century, Jason Samson, Dominique Berteaux, Brian Mcgill, Murray Humphries Oct 2012

Demographic Amplification Of Climate Change Experienced By The Contiguous United States Population During The 20th Century, Jason Samson, Dominique Berteaux, Brian Mcgill, Murray Humphries

Publications

Better understanding of the changing relationship between human populations and climate is a global research priority. The 20th century in the contiguous United States offers a particularly well-documented example of human demographic expansion during a period of radical socioeconomic and environmental change. One would expect that as human society has been transformed by technology, we would become increasingly decoupled from climate and more dependent on social infrastructure. Here we use spatially-explicit models to evaluate climatic, socio-economic and biophysical correlates of demographic change in the contiguous United States between 1900 and 2000. Climate-correlated variation in population growth has caused the U ...


An Infrastructure To Support Data Integration And Curation For Higher Educational Research, Linh B. Ngo, Amy W. Apon, Pengfei Xuan, Kimberley Ferguson, Christin Marshall, John Mccann, Yueli Zheng Oct 2012

An Infrastructure To Support Data Integration And Curation For Higher Educational Research, Linh B. Ngo, Amy W. Apon, Pengfei Xuan, Kimberley Ferguson, Christin Marshall, John Mccann, Yueli Zheng

Publications

The recent challenges for higher education call for research that can offer a comprehensive understanding about the performance and efficiency of higher education institutions in their three primary missions: research, education, and service. In other for this to happen, it is necessary for researchers to have access to a multitude of data sources.However, due to the nature of their academic training, many higher education practitioners do not have access to expertise in working with different data sources. In this work, we describe a design and implementation for an infrastructure that will bring together the tools and the data to ...


Highly Efficient And Exact Method For Parallelization Of Grid-Based Algorithms And Its Implementation In Delphi, Chuan Li, Lin Li, Jie Zhang, Emil Alexov Sep 2012

Highly Efficient And Exact Method For Parallelization Of Grid-Based Algorithms And Its Implementation In Delphi, Chuan Li, Lin Li, Jie Zhang, Emil Alexov

Publications

The Gauss–Seidel (GS) method is a standard iterative numerical method widely used to solve a system of equations and, in general, is more efficient comparing to other iterative methods, such as the Jacobi method. However, standard implementation of the GS method restricts its utilization in parallel computing due to its requirement of using updated neighboring values (i.e., in current iteration) as soon as they are available. Here, we report an efficient and exact (not requiring assumptions) method to parallelize iterations and to reduce the computational time as a linear/nearly linear function of the number of processes or ...


A Deep Search For Host Galaxies Of Grbs With No Detected Optical Afterglow, A. Rossi, S. Klose, P. Ferrero, J. Greiner, L. A. Arnold, E. Gonslaves, Dieter H. Hartmann, A. C. Updike, D. A. Kann, T. Krühler Sep 2012

A Deep Search For Host Galaxies Of Grbs With No Detected Optical Afterglow, A. Rossi, S. Klose, P. Ferrero, J. Greiner, L. A. Arnold, E. Gonslaves, Dieter H. Hartmann, A. C. Updike, D. A. Kann, T. Krühler

Publications

Context. Gamma-ray bursts (GRBs) can provide information about star formation at high redshifts. Even in the absence of a bright optical/near-infrared/radio afterglow, the high detection rate of X-ray afterglows by Swift/XRT and its localization precision of 2–3 arcsec facilitates the identification and the study of GRB host galaxies. Aims. We focus on the search for the host galaxies of 17 bursts with arcsec-sized XRT error circles but no detected long-wavelength afterglow, in spite of their deep and rapid follow-up observations. Three of these events can also be classified as truly dark bursts, i.e., the observed ...


Biodegradation Of Textile Dye Anthraquinone Vat Blue 4 By Pseudomonas Aeruginosa, Rajee Olaganathan, Jamila Patterson Aug 2012

Biodegradation Of Textile Dye Anthraquinone Vat Blue 4 By Pseudomonas Aeruginosa, Rajee Olaganathan, Jamila Patterson

Publications

Uncontaminated and Vat blue 4 contaminated soil were screened for heterotrophic bacterial population and the bacterial density were found to be 19.3 X 104 and 5.5 X 104 CFU/gm respectively. The bacterial genera of dye contaminated soil was dominated by Pseudomonas sp. (32.5 %) followed by Bacillus sp. (27.5 %), Aeromonas sp. (15.0 %), Micrococcus sp. (12.5 %) and Achromobacter sp. (12.5 %). The optimum inoculums load, pH and temperature were found to be 5%, 7 and 35oC respectively. The initial pH of the effluent prepared using Vat Blue 4 was 8.5. The free cells of ...


On The Cyclically Fully Commutative Elements Of Coxeter Groups, T. Boothby, J. Burket, M. Eichwald, D. C. Ernst, R. M. Green, Matthew Macauley Aug 2012

On The Cyclically Fully Commutative Elements Of Coxeter Groups, T. Boothby, J. Burket, M. Eichwald, D. C. Ernst, R. M. Green, Matthew Macauley

Publications

Let W be an arbitrary Coxeter group. If two elements have expressions that are cyclic shifts of each other (as words), then they are conjugate (as group elements) in W. We say that w is cyclically fully commutative (CFC) if every cyclic shift of any reduced expression for w is fully commutative (i.e., avoids long braid relations). These generalize Coxeter elements in that their reduced expressions can be described combinatorially by acyclic directed graphs, and cyclically shifting corresponds to source-to-sink conversions. In this paper, we explore the combinatorics of the CFC elements and enumerate them in all Coxeter groups ...


The Gaise College Report: The American Statistical Association Meets Sound Pedagogy In Central Virginia, Beverly Wood Aug 2012

The Gaise College Report: The American Statistical Association Meets Sound Pedagogy In Central Virginia, Beverly Wood

Publications

Research in undergraduate statistics education often centers on the introductory course required for a large percentage of college students. While acknowledging the diverse setting, audience, and purpose of introductory courses, existing research assumes that courses offered by different disciplines share the same goals and teaching practices. The purpose of this study is to examine the objectives for student outcomes and pedagogical delivery of introductory statistics courses in various academic departments to provide explicit evidence for this assumption. The American Statistical Association’s Guidelines for Assessment and Instruction in Statistics Education (GAISE) are meant to apply to all introductory courses. The ...


The Gas/Dust Ratio Of Circumstellar Disks: Testing Models Of Planetesimal Formation, David Horne, Erika Gibb, Terrence W. Rettig, Sean D. Brittain, David Tilley, Dinshaw Balsara Jul 2012

The Gas/Dust Ratio Of Circumstellar Disks: Testing Models Of Planetesimal Formation, David Horne, Erika Gibb, Terrence W. Rettig, Sean D. Brittain, David Tilley, Dinshaw Balsara

Publications

We present high-resolution, near-infrared NIRSPEC observations of CO absorption toward six class II T Tauri stars: AA Tau, DG Tau, IQ Tau, RY Tau, CW Tau, and Haro 6–5b. 12CO overtone absorption lines originating from the circumstellar disk of each object were used to calculate line-of-sight gas column densities toward each source. We measured the gas/dust ratio as a function of disk inclination, utilizing measured visual extinctions and inclinations for each star. The majority of our sources show further evidence for a correlation between the gas/dust columndensity ratio and disk inclination similar to that found by Rettig ...


The Influence Of Automation On Aviation Accident And Fatality Rates: 2000-2010, Nicholas A. Koeppen Jul 2012

The Influence Of Automation On Aviation Accident And Fatality Rates: 2000-2010, Nicholas A. Koeppen

Publications

The purpose of this project is to evaluate if technological advances and implementation of automation have produced a decrease in the number and severity of accidents in commercial aviation over the last decade. To accomplish this evaluation historical commercial aviation accident data from 2000 to 2010 will be examined. Commercial fixed wing and rotary wing data will be evaluated. No aviation incident data will be collected; the project will be limited in scope to commercial aviation accidents. Accidents highlighting major deficiencies involving automation will be discussed in detail. To further support the projects purpose, emphasis will be given to evaluate ...


Ionospheric Signatures Of Tohoku-Oki Tsunami Of March 11, 2011: Model Comparisons Near The Epicenter, David A. Galvan, Attila Komjathy, Michael P. Hickey, Philip Stephens, Jonathan Snively, Y. Tony Song, Mark D. Butala, Anthony J. Mannucci Jul 2012

Ionospheric Signatures Of Tohoku-Oki Tsunami Of March 11, 2011: Model Comparisons Near The Epicenter, David A. Galvan, Attila Komjathy, Michael P. Hickey, Philip Stephens, Jonathan Snively, Y. Tony Song, Mark D. Butala, Anthony J. Mannucci

Publications

We observe ionospheric perturbations caused by the Tohoku earthquake and tsunami of March 11, 2011. Perturbations near the epicenter were found in measurements of ionospheric total electron content (TEC) from 1198 GPS receivers in the Japanese GEONET network. For the first time for this event, we compare these observations with the estimated magnitude and speed of a tsunami-driven atmospheric gravity wave, using an atmosphere-ionosphere-coupling model and a tsunami model of sea-surface height, respectively. Traveling ionospheric disturbances (TIDs) were observed moving away from the epicenter at approximate speeds of 3400 m/s, 1000 m/s and 200–300 m/s, consistent ...


Elastic Properties Of The Zintl Ferromagnet Yb14mnsb11, Sriparna Bhattacharya, D C. Marinescu, James R. Morris, Ivan A. Sergienko, Brian Sales, David Madrus, Veerle Keppens Jul 2012

Elastic Properties Of The Zintl Ferromagnet Yb14mnsb11, Sriparna Bhattacharya, D C. Marinescu, James R. Morris, Ivan A. Sergienko, Brian Sales, David Madrus, Veerle Keppens

Publications

We report measurements of the elastic moduli as a function of temperature (5–300) K and magnetic field (0–2 T) for the Zintl ferromagnet Yb14MnSb11, which is believed to be a rare example of an underscreened Kondo lattice. The elastic moduli measured below the Curie temperature in this complex ferromagnet exhibit unusual lattice stiffening that is independent of the magnetic field and can be adequately modeled using the Landau theory.


Herschel/Pacs Observations Of Young Sources In Taurus: The Far-Infrared Counterpart Of Optical Jets, L Podio, I Kamp, D Flower, C Howard, G Sandell, A Mora, G Aresu, Sean D. Brittain, W.R.F. Dent, C Pinte, G J. White Jul 2012

Herschel/Pacs Observations Of Young Sources In Taurus: The Far-Infrared Counterpart Of Optical Jets, L Podio, I Kamp, D Flower, C Howard, G Sandell, A Mora, G Aresu, Sean D. Brittain, W.R.F. Dent, C Pinte, G J. White

Publications

Context. Observations of the atomic and molecular line emission associated with jets and outflows emitted by young stellar objects provide sensitive diagnostics of the excitation conditions, and can be used to trace the various evolutionary stages they pass through as they evolve to become main sequence stars. Aims. To understand the relevance of atomic and molecular cooling in shocks, and how accretion and ejection efficiency evolves with the evolutionary state of the sources, we will study the far-infrared counterparts of bright optical jets associated with Class I and II sources in Taurus (T Tau, DG Tau A, DG Tau B ...


Observed Seasonal Variations In Exospheric Effective Temperatures, E. J. Mierkiewicz, F. L. Roesler, S. M. Nossal Jun 2012

Observed Seasonal Variations In Exospheric Effective Temperatures, E. J. Mierkiewicz, F. L. Roesler, S. M. Nossal

Publications

High spectral resolution line profile observations indicate a reproducible semi-annual variation in the geocoronal hydrogen Balmer α effective temperature. These observations were made between 08 January 2000 and 21 November 2001 from Pine Bluff Observatory (WI) with a second generation double etalon Fabry-Perot annular summing spectrometer operating at a resolving power of 80,000. This data set spans sixty-four nights of observations (1404 spectra in total) over 20 dark-moon periods. A two cluster Gaussian model fitting procedure is used to determine Doppler line widths, accounting for fine structure contributions to the line, including those due to cascade; cascade contributions at ...


Ionospheric Plasma Transport And Loss In Auroral Downward Current Regions, M. Zettergren, J. L. Semeter Jun 2012

Ionospheric Plasma Transport And Loss In Auroral Downward Current Regions, M. Zettergren, J. L. Semeter

Publications

A detailed study of the effects of auroral current systems on thermal ionospheric plasma transport and loss is conducted using a new ionospheric model. The mathematical formulation of the model is a variation on the 5‐moment approximation which describes the temporal evolution of density, drift, and temperature for five different ion species in two spatial dimensions. The fluid system is closed through a 2‐D electrostatic treatment of the auroral currents. This model is used to examine the interplay between ion heating, perpendicular transport, molecular ion generation, and type‐1 ion upflows in a self‐consistent way for the ...


Topological Thermoelectric Effects In Spin-Orbit Coupled Electron- And Hole-Doped Semiconductors, E Dumitrescu, Chuanwei Zhang, D C. Marinescu, Sumanta Tewari Jun 2012

Topological Thermoelectric Effects In Spin-Orbit Coupled Electron- And Hole-Doped Semiconductors, E Dumitrescu, Chuanwei Zhang, D C. Marinescu, Sumanta Tewari

Publications

We compute the intrinsic contributions to the Berry-phase mediated anomalous Hall and Nernst effects in electron- and hole-doped semiconductors in the presence of an in-plane magnetic field as well as Rashba and Dresselhaus spin-orbit couplings. For both systems we find that the regime of chemical potential which supports the topological superconducting state in the presence of the superconducting proximity effect can be characterized by plateaus in the topological Hall and Nernst coefficients flanked by well-defined peaks marking the emergence of the topological regime. The plateaus arise from a clear momentum space separation between the region where the Berry curvature is ...


Observations Of Herbig Ae/Be Stars With Herschel/Pacs. The Atomic And Molecular Contents Of Their Protoplanetary Discs, G Meeus, B Montesinos, I Mendigutia, I Kamp, W F. Thi, C Eiroa, C A. Grady, G Mathews, G Sandell, C. Martin-Zaidi, Sean D. Brittain, W.R.F. Dent, C Howard, F Menard, C Pinte, A Roberge, B Vandenbussche, J P. Williams Jun 2012

Observations Of Herbig Ae/Be Stars With Herschel/Pacs. The Atomic And Molecular Contents Of Their Protoplanetary Discs, G Meeus, B Montesinos, I Mendigutia, I Kamp, W F. Thi, C Eiroa, C A. Grady, G Mathews, G Sandell, C. Martin-Zaidi, Sean D. Brittain, W.R.F. Dent, C Howard, F Menard, C Pinte, A Roberge, B Vandenbussche, J P. Williams

Publications

We observed a sample of 20 representative Herbig Ae/Be stars and 5 A-type debris discs with PACS onboard Herschel, as part of the GAS in Protoplanetary Systems (GASPS) project. The observations were done in spectroscopic mode, and cover the far-infrared lines of [O i], [C ii], CO, CH+, H2O, and OH. We have a [Oi] 63 μm detection rate of 100% for the Herbig Ae/Be and 0% for the debris discs. The [Oi] 145 μm line is only detected in 25% and CO J = 18–17 in 45% (and fewer cases for higher J transitions) of the Herbig ...


Predicting Nonspecific Ion Binding Using Delphi, Marharyta Petukh, Maxim Zhenirovskyy, Chuan Li, Lin Li, Lin Wang, Emil Alexov Jun 2012

Predicting Nonspecific Ion Binding Using Delphi, Marharyta Petukh, Maxim Zhenirovskyy, Chuan Li, Lin Li, Lin Wang, Emil Alexov

Publications

Ions are an important component of the cell and affect the corresponding biological macromolecules either via direct binding or as a screening ion cloud. Although some ion binding is highly specific and frequently associated with the function of the macromolecule, other ions bind to the protein surface nonspecifically, presumably because the electrostatic attraction is strong enough to immobilize them. Here, we test such a scenario and demonstrate that experimentally identified surface-bound ions are located at a potential that facilitates binding, which indicates that the major driving force is the electrostatics. Without taking into consideration geometrical factors and structural fluctuations, we ...


Topology And Geometry Of Mixing Of Fluids, Andrei Ludu, Stefan Mancas, Ionutz Ionescu, Audrey Gbagaudi, Matthew Schumacher Jun 2012

Topology And Geometry Of Mixing Of Fluids, Andrei Ludu, Stefan Mancas, Ionutz Ionescu, Audrey Gbagaudi, Matthew Schumacher

Publications

We present an enhancement of diffusive mixing on a compact Riemannian manifold by a fast incompressible flow.

We describe the class of flows that make the deviation of the solution from its average arbitrarily small in an arbitrarily short time, provided that the flow amplitude is large enough.

The necessary and sufficient condition on such flows is expressed naturally in terms of the spectral properties of the dynamical system associated with the flow.

Further studies are needed for non-compact manifolds, or compact manifolds with Dirichlet BC. The optimal shape of the fixed obstacles in the mixing device could be obtained ...


2d Novel Structures Along An Opitcal Fiber, Charles-Julien Vandamme, Stefan C. Mancas Jun 2012

2d Novel Structures Along An Opitcal Fiber, Charles-Julien Vandamme, Stefan C. Mancas

Publications

By using spectral methods, we present seven classes of stable and unstable structures that occur in a dissipative media. By varying parameters and initial conditions we find ranges of existence of stable structures (spinning elliptic, pulsating, stationary, organized exploding), and unstable structures (filament, disorganized exploding, creeping). By varying initial conditions, vorticity, and parameters of the equation, we find a reacher behavior of solutions in the form of creeping-vortex (propellers), spinning rings and spinning “bean-shape” solitons. Each class differentiates from the other by distinctive features of their shape and energy evolution, as well as domain of existence.


Gravity Wave Propagation In A Diffusively Separated Gas: Effects On The Total Gas, Michael P. Hickey Ph.D., R. L. Walterscheid May 2012

Gravity Wave Propagation In A Diffusively Separated Gas: Effects On The Total Gas, Michael P. Hickey Ph.D., R. L. Walterscheid

Publications

We present a full-wave model that simulates acoustic-gravity wave propagation in a binary-gas mixture of atomic oxygen and molecular nitrogen, including molecular viscosity and thermal conductivity appropriately partitioned between the two gases. Compositional effects include the collisional transfer of heat and momentum by mutual diffusion between the two gases. An important result of compositional effects is that the velocity and temperature summed over species can be significantly different from the results of one-gas models with the same height dependent mean molecular weight (M(z)). We compare the results of our binary-gas model to two one-gas full-wave models: one where M ...


Delphi: A Comprehensive Suite For Delphi Software And Associated Resources, Lin Li, Chuan Li, Subhra Sarkar, Jie Zhang, Shawn Witham, Zhe Zhang, Lin Wang, Nicholas Smith, Marharyta Petukh, Emil Alexov May 2012

Delphi: A Comprehensive Suite For Delphi Software And Associated Resources, Lin Li, Chuan Li, Subhra Sarkar, Jie Zhang, Shawn Witham, Zhe Zhang, Lin Wang, Nicholas Smith, Marharyta Petukh, Emil Alexov

Publications

Background

Accurate modeling of electrostatic potential and corresponding energies becomes increasingly important for understanding properties of biological macromolecules and their complexes. However, this is not an easy task due to the irregular shape of biological entities and the presence of water and mobile ions.

Results

Here we report a comprehensive suite for the well-known Poisson-Boltzmann solver, DelPhi, enriched with additional features to facilitate DelPhi usage. The suite allows for easy download of both DelPhi executable files and source code along with a makefile for local installations. The users can obtain the DelPhi manual and parameter files required for the corresponding ...


Book Review: Astronomy At The Frontiers Of Science, T. D. Oswalt May 2012

Book Review: Astronomy At The Frontiers Of Science, T. D. Oswalt

Publications

This document is Dr. Oswalt’s review of Astronomy at the Frontiers of Science, edited by Jean-Pierre Lasota, Springer, 2011. 357p, 9789400716575 $179.00.