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2014

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Articles 1 - 30 of 69

Full-Text Articles in Physical Sciences and Mathematics

Mitigating The Effects Of Climate Change With Wind Energy And Gis, Rachael Isphording, Richard Snow, Mary Snow Dec 2014

Mitigating The Effects Of Climate Change With Wind Energy And Gis, Rachael Isphording, Richard Snow, Mary Snow

Publications

The climate is changing, and humans are heavily exacerbating these changes. As the effects of climate change are being felt across the planet, scientists and policy makers are uniting to increase mitigation efforts and are researching renewable, clean energy sources to reduce the amount of greenhouse gas emissions released into the atmosphere during energy production. Of the different renewable energy technologies, wind energy is one of the most researched and implemented. Over the past twenty years, researchers have been applying Geographic Information Systems (GIS) to their climate change studies. GIS allows the user to spatially view, manipulate, and analyze data ...


A Deep Proper Motion Catalog Within The Sloan Digital Sky Survey Footprint, Jeffrey A. Munn, Hugh C. Harris, Ted Von Hippel, Mukremin Kilic, James W. Liebert, Kurtis A. Williams, Steven Degenarro, Elizabeth Jeffery, Trudy M. Tilleman Dec 2014

A Deep Proper Motion Catalog Within The Sloan Digital Sky Survey Footprint, Jeffrey A. Munn, Hugh C. Harris, Ted Von Hippel, Mukremin Kilic, James W. Liebert, Kurtis A. Williams, Steven Degenarro, Elizabeth Jeffery, Trudy M. Tilleman

Publications

A new proper motion catalog is presented, combining the Sloan Digital Sky Survey (SDSS) with second epoch observations in the r band within a portion of the SDSS imaging footprint. The new observations were obtained with the 90prime camera on the Steward Observatory Bok 90 inch telescope, and the Array Camera on the U.S. Naval Observatory, Flagstaff Station, 1.3 m telescope. The catalog covers 1098 square degrees to r = 22.0, an additional 1521 square degrees to r = 20.9, plus a further 488 square degrees of lesser quality data. Statistical errors in the proper motions range from ...


The Power Of Principled Bayesian Methods In The Study Of Stellar Evolution, Ted Von Hippel, David Van Dyk, David Stenning, Elliot Robinson, Elizabeth Jeffery, Nathan Stein, William Jefferys, Erin M. O'Malley Nov 2014

The Power Of Principled Bayesian Methods In The Study Of Stellar Evolution, Ted Von Hippel, David Van Dyk, David Stenning, Elliot Robinson, Elizabeth Jeffery, Nathan Stein, William Jefferys, Erin M. O'Malley

Publications

It takes years of effort employing the best telescopes and in- struments to obtain high-quality stellar photometry, astrometry, and spectroscopy. Stellar evolution models contain the experience of life- times of theoretical calculations and testing. Yet most astronomers fit these valuable models to these precious datasets by eye. We show that a principled Bayesian approach to fitting models to stellar data yields substantially more information over a range of stellar astrophysics. We highlight advances in determining the ages of star clusters, mass ratios of binary stars, limitations in the accuracy of stellar models, post-main-sequence mass loss, and the ages of individual ...


Bayesian Analysis For Stellar Evolution With Nine Parameters (Base-9): User's Manual, Ted Von Hippel, Elliot Robinson, Elizabeth Jeffery, Rachel Wagner-Kaiser, Steven Degennaro, Nathan Stein, David Stenning, William H. Jefferys, David Van Dyk Nov 2014

Bayesian Analysis For Stellar Evolution With Nine Parameters (Base-9): User's Manual, Ted Von Hippel, Elliot Robinson, Elizabeth Jeffery, Rachel Wagner-Kaiser, Steven Degennaro, Nathan Stein, David Stenning, William H. Jefferys, David Van Dyk

Publications

BASE-9 is a Bayesian software suite that recovers star cluster and stellar parameters from photometry. BASE-9 is useful for analyzing single-age, single-metallicity star clusters, binaries, or single stars, and for simulating such systems. BASE-9 uses Markov chain Monte Carlo and brute-force numerical integration techniques to estimate the posterior probability distributions for the age, metallicity, helium abundance, distance modulus, and line-of-sight absorption for a cluster, and the mass, binary mass ratio, and cluster membership probability for every stellar object. BASE-9 is provided as open source code on a version-controlled web server. The executables are also available as Amazon Elastic Compute Cloud ...


Development Of A Stakeholder-Driven Spatial Modeling Framework For Strategic Landscape Planning Using Bayesian Networks Across Two Urban-Rural Gradients In Maine, Usa, Spencer Meyer, Michelle Johnson, Robert Lilieholm, Christopher Cronan Nov 2014

Development Of A Stakeholder-Driven Spatial Modeling Framework For Strategic Landscape Planning Using Bayesian Networks Across Two Urban-Rural Gradients In Maine, Usa, Spencer Meyer, Michelle Johnson, Robert Lilieholm, Christopher Cronan

Publications

Land use change results from frequent, independent actions by decision-makers working in isolation, often with a focus on a single land use. In order to develop integrated land use policies that encourage sustainable outcomes, scientists and practitioners must understand the specific drivers of land use change across mixed land use types and ownerships, and must consider the combined influences of biophysical, economic, and social factors that affect land use decisions. In this analysis of two large watersheds covering a total of 1.9 million hectares in Maine, USA, we co-developed with groups of stakeholders land use suitability models that integrated ...


Book Review: Planetary Rings: A Post-Equinox View 2nd Ed, T. D. Oswalt Nov 2014

Book Review: Planetary Rings: A Post-Equinox View 2nd Ed, T. D. Oswalt

Publications

This document is Dr. Oswalt’s review of Planetary Rings : a Post-Equinox View 2nd Ed. by Larry W. Esposito, Cambridge, 2014 246p bibl index, 9781107028821 $120.00


Numerical Simulation Of The Long-Range Propagation Of Gravity Wave Packets At High Latitudes, C. J. Heale, J. B. Snively, M. P. Hickey Oct 2014

Numerical Simulation Of The Long-Range Propagation Of Gravity Wave Packets At High Latitudes, C. J. Heale, J. B. Snively, M. P. Hickey

Publications

We use a 2-D, nonlinear, time-dependent numerical model to simulate the propagation of wave packets under average high latitude, winter conditions. We investigate the ability of waves to propagate large horizontal distances, depending on their direction of propagation relative to the average modeled ambient winds. Wave sources were specified to represent the following: (1) the most common wave parameters inferred from observations of Nielsen et al. (2009) ((18 km λᵪ , 7.5 min period), (2) waves consistent with the average phase speed observed (40 m/s) but outlying horizontal wavelength and period values (40 km λᵪ , 17 min period), and ...


Rational Design Of Small-Molecule Stabilizers Of Spermine Synthase Dimer By Virtual Screening And Free Energy-Based Approach, Zhe Zhang, Virginie Martiny, David Lagorce, Yoshihiko Ikeguchi, Emil Alexov, Maria A. Miteva Oct 2014

Rational Design Of Small-Molecule Stabilizers Of Spermine Synthase Dimer By Virtual Screening And Free Energy-Based Approach, Zhe Zhang, Virginie Martiny, David Lagorce, Yoshihiko Ikeguchi, Emil Alexov, Maria A. Miteva

Publications

Snyder-Robinson Syndrome (SRS) is a rare mental retardation disorder which is caused by the malfunctioning of an enzyme, the spermine synthase (SMS), which functions as a homo-dimer. The malfunctioning of SMS in SRS patients is associated with several identified missense mutations that occur away from the active site. This investigation deals with a particular SRS-causing mutation, the G56S mutation, which was shown computationally and experimentally to destabilize the SMS homo-dimer and thus to abolish SMS enzymatic activity. As a proof-of-concept, we explore the possibility to restore the enzymatic activity of the malfunctioning SMS mutant G56S by stabilizing the dimer through ...


Synthetic Data Generation For The Internet Of Things, Jason Anderson, K. E. Kennedy, Linh B. Ngo, Andre Luckow, Amy Apon Oct 2014

Synthetic Data Generation For The Internet Of Things, Jason Anderson, K. E. Kennedy, Linh B. Ngo, Andre Luckow, Amy Apon

Publications

The concept of Internet of Things (IoT) is rapidly moving from a vision to being pervasive in our everyday lives. This can be observed in the integration of connected sensors from a multitude of devices such as mobile phones, healthcare equipment, and vehicles. There is a need for the development of infrastructure support and analytical tools to handle IoT data, which are naturally big and complex. But, research on IoT data can be constrained by concerns about the release of privately owned data. In this paper, we present the design and implementation results of a synthetic IoT data generation framework ...


Shifted One-Parameter Supersymmetric Family Of Quartic Asymmetric Double-Well Potentials, Haret C. Rosu, Stefan C. Mancas, Pisin Chen Oct 2014

Shifted One-Parameter Supersymmetric Family Of Quartic Asymmetric Double-Well Potentials, Haret C. Rosu, Stefan C. Mancas, Pisin Chen

Publications

Extending our previous work (Rosu, Mancas, Chen, Ann.Phys. 343 (2014) 87-102), we define supersymmetric partner potentials through a particular Riccati solution of the form F (x) = (x - c)^2 - 1, where c is a real shift parameter, and work out the quartic double-well family of one-parameter isospectral potentials obtained by using the corresponding general Riccati solution. For these parametric double well potentials, we study how the localization properties of the two wells depend on the parameter of the potentials for various values of the shifting parameter.


Investigation Of A Mesospheric Gravity Wave Ducting Event Using Coordinated Sodium Lidar And Mesospheric Temperature Mapper Measurements At Alomar, Norway (69°N), Katrina Bossert, David C. Fritts, Pierre-Dominique Pautet, Michael J. Taylor, Bifford P. Williams, William R. Pendleton Jr. Aug 2014

Investigation Of A Mesospheric Gravity Wave Ducting Event Using Coordinated Sodium Lidar And Mesospheric Temperature Mapper Measurements At Alomar, Norway (69°N), Katrina Bossert, David C. Fritts, Pierre-Dominique Pautet, Michael J. Taylor, Bifford P. Williams, William R. Pendleton Jr.

Publications

New measurements at the ALOMAR observatory in northern Norway (69°N, 16°E) using the Weber sodium lidar and the Advanced Mesospheric Temperature Mapper (AMTM) allow for a comprehensive investigation of a gravity wave (GW) event on 22 and 23 January 2012 and the complex and varying propagation environment in which the GW was observed. These observational techniques provide insight into the altitude ranges over which a GW may be evanescent or propagating and enable a clear distinction in specific cases. Weber sodium lidar measurements provide estimates of background temperature, wind, and stability profiles at altitudes from ~78 to 105 ...


A Coordinated Investigation Of The Gravity Wave Breaking And The Associated Dynamical Instability By A Na Lidar And An Advanced Mesosphere Temperature Mapper Over Logan, Ut (41.7°N, 111.8°W), Xuguang Cai, Tao Yuan, Yucheng Zhao, Pierre-Dominique Pautet, Michael J. Taylor, William R. Pendleton Jr. Aug 2014

A Coordinated Investigation Of The Gravity Wave Breaking And The Associated Dynamical Instability By A Na Lidar And An Advanced Mesosphere Temperature Mapper Over Logan, Ut (41.7°N, 111.8°W), Xuguang Cai, Tao Yuan, Yucheng Zhao, Pierre-Dominique Pautet, Michael J. Taylor, William R. Pendleton Jr.

Publications

The impacts of gravity wave (GW) on the thermal and dynamic characteristics within the mesosphere/lower thermosphere, especially on the atmospheric instabilities, are still not fully understood. In this paper, we conduct a comprehensive and detailed investigation on one GW breaking event during a collaborative campaign between the Utah State University Na lidar and the Advanced Mesospheric Temperature Mapper (AMTM) on 9 September 2012. The AMTM provides direct evidence of the GW breaking as well as the horizontal parameters of the GWs involved, while the Na lidar's full diurnal cycle observations are utilized to uncover the roles of tide ...


The Geocoronal H Α Cascade Component Determined From Geocoronal H Β Intensity Measurements, F. L. Roesler, E. J. Mierkiewicz, S. M. Nossal Aug 2014

The Geocoronal H Α Cascade Component Determined From Geocoronal H Β Intensity Measurements, F. L. Roesler, E. J. Mierkiewicz, S. M. Nossal

Publications

"Geocoronal H α and H β intensity measurements using the Wisconsin H α Mapper Fabry-Perot are used to determine the intensity of the H α cascade component. From basic atomic physics and the work of Meier (1995), we show that the total cascade in geocoronal H α emission is 0.52 ± 0.03 times the geocoronal H β intensity, I(H β), for solar Lyman series excitation of geocoronal hydrogen. The results are consistent with the H α cascade measurements of Mierkiewicz et al. (2012), which were determined directly from the analysis of H α line profile measurements, and significantly ...


A Statistical Study Of Magnetic Field Fluctuations In The Dayside Magnetosheath And Their Dependence On Upstream Solar Wind Conditions, A. P. Dimmock, K. Nykyri, T. I. Pulkkinen Aug 2014

A Statistical Study Of Magnetic Field Fluctuations In The Dayside Magnetosheath And Their Dependence On Upstream Solar Wind Conditions, A. P. Dimmock, K. Nykyri, T. I. Pulkkinen

Publications

The magnetosheath functions as a natural interface connecting the interplanetary and magnetospheric plasma. Since the magnetosheath houses the shocked solar wind, it is populated with abundant magnetic field turbulence which are generated both locally and externally. Although the steady state magnetosheath is to date relatively well understood, the same cannot be said of transient magnetic perturbations due to their kinetic nature and often complex and numerous generation mechanisms. The current manuscript presents a statistical study of magnetic field fluctuations in the dayside magnetosheath as a function of upstream solar wind conditions. We concentrate on the ambient higher-frequency fluctuations in the ...


Potential And Technological Advancement Of Biofuels, Rajee Olaganathan, Fabian Ko Qui Shen, Lim Jun Shen Aug 2014

Potential And Technological Advancement Of Biofuels, Rajee Olaganathan, Fabian Ko Qui Shen, Lim Jun Shen

Publications

This scientific paper examines the feasibility of biofuels as a solution to the world‟s energy crisis. It studies the development of the four different generations of biofuel that have been discerned over the years, determining the pros and cons of each. The paper further investigates the issues concerning each generation, and determines how their successors have solved and improved on those problems. In order to give the reader an unbiased perspective, the paper studies both general advantages and disadvantages that encompasses social, economic and environmental impacts. Research and development on the first two generations of biofuels have matured, and ...


Nonadiabatic Heating In Magnetic Reconnection, Xuanye Ma, Antonius Otto Jul 2014

Nonadiabatic Heating In Magnetic Reconnection, Xuanye Ma, Antonius Otto

Publications

Plasma transport process as a fundamental problem in magnetospheric physics is often associated with strong nonadiabatic heating. At the magnetopause, observations show an increase of specific entropy (i.e., S = p/ργ) by 2 orders of magnitude from the magnetosheath into the magnetosphere. In the near‐Earth magnetotail, particle injection requires strongly entropy depleted plasma bubbles, and their evolution can be strongly modified in the presence of nonadiabatic heating. In this study, one of the critical plasma transport mechanisms, magnetic reconnection, is investigated as a nonadiabatic process in the framework of MHD. It is important to examine whether magnetic reconnection ...


Variable Viscosity Condition In The Modeling Of A Slider Bearing, Kedar Nath Uprety, Stefan C. Mancas Jul 2014

Variable Viscosity Condition In The Modeling Of A Slider Bearing, Kedar Nath Uprety, Stefan C. Mancas

Publications

To reduce tear and wear of machinery lubrication is essential. Lubricants form a layer between two surfaces preventing direct contact and reduce friction between moving parts and hence reduce wear. In this short letter the lubrication of two slider bearings with parallel and nonparallel is studied. First, we show that bearings with parallel plates cannot support any load. For bearings with nonparallel plates we are interested on how constant and temperature dependent viscosity affects the properties of the bearings. Also, a critical temperature for which the bearings would fail due to excess in temperature is found for both latter cases ...


Problm Web Server: Protein And Membrane Placement And Orientation Package, Taylor Kimmett, Nicholas Smith, Shawn Witham, Marharyta Petukh, Subhra Sarkar, Emil Alexov Jul 2014

Problm Web Server: Protein And Membrane Placement And Orientation Package, Taylor Kimmett, Nicholas Smith, Shawn Witham, Marharyta Petukh, Subhra Sarkar, Emil Alexov

Publications

The 3D structures of membrane proteins are typically determined without the presence of a lipid bilayer. For the purpose of studying the role of membranes on the wild type characteristics of the corresponding protein, determining the position and orientation of transmembrane proteins within a membrane environment is highly desirable. Here we report a geometry-based approach to automatically insert a membrane protein with a known 3D structure into pregenerated lipid bilayer membranes with various dimensions and lipid compositions or into a pseudomembrane. The pseudomembrane is built using the Protein Nano-Object Integrator which generates a parallelepiped of user-specified dimensions made up of ...


The Life Cycle Of Instability Features Measured From The Andes Lidar Observatory Over Cerro Pachon On 24 March 2012, J. H. Hecht, K. Wan, L. J. Gelinas, David C. Fritts, R. L. Walterscheid, R. J. Rudy, A. Z. Liu, S. J. Franke, F. A. Vargas, Pierre-Dominique Pautet, Michael J. Taylor, G. R. Swenson Jun 2014

The Life Cycle Of Instability Features Measured From The Andes Lidar Observatory Over Cerro Pachon On 24 March 2012, J. H. Hecht, K. Wan, L. J. Gelinas, David C. Fritts, R. L. Walterscheid, R. J. Rudy, A. Z. Liu, S. J. Franke, F. A. Vargas, Pierre-Dominique Pautet, Michael J. Taylor, G. R. Swenson

Publications

The Aerospace Corporation's Nightglow Imager (ANI) observes nighttime OH emission (near 1.6 μm) every 2 s over an approximate 73° field of view. ANI had previously been used to study instability features seen over Maui. Here we describe observations of instabilities seen from 5 to 8 UT on 24 March 2012 over Cerro Pachon, Chile, and compare them with previous results from Maui, with theory, and with Direct Numerical Simulations (DNS). The atmosphere had reduced stability because of the large negative temperature gradients measured by a Na lidar. Thus, regions of dynamical and convective instabilities are expected to ...


Ermakov-Lewis Invariants And Reid Systems, Stefan C. Mancas, Haret C. Rosu Jun 2014

Ermakov-Lewis Invariants And Reid Systems, Stefan C. Mancas, Haret C. Rosu

Publications

Reid's mth-order generalized Ermakov systems of nonlinear coupling constant α are equivalent to an integrable Emden–Fowler equation. The standard Ermakov–Lewis invariant is discussed from this perspective, and a closed formula for the invariant is obtained for the higher-order Reid systems (m≥3). We also discuss the parametric solutions of these systems of equations through the integration of the Emden–Fowler equation and present an example of a dynamical system for which the invariant is equivalent to the total energy.


High-Resolution Spectroscopy Of The Lunar Sodium Exosphere, E. J. Mierkiewicz, R. J. Oliversen, F. L. Roesler, O. L. Lupie Jun 2014

High-Resolution Spectroscopy Of The Lunar Sodium Exosphere, E. J. Mierkiewicz, R. J. Oliversen, F. L. Roesler, O. L. Lupie

Publications

"We have applied high-resolution Fabry-Perot spectroscopy to the study of the lunar sodium exosphere for the study of exospheric effective temperature and velocity variations. Observing from the National Solar Observatory McMath-Pierce Telescope, we used a dual-etalon Fabry-Perot spectrometer with a resolving power of 180,000 to measure line widths and Doppler shifts of the sodium D2 (5889.95 Å) emission line. Our field of view was 360 km, and measurements were made in equatorial and polar regions from 500 km to 3500 km off the limb. Data were obtained from full moon to 3 days following full moon (waning phase ...


Bridging The Divide: Tensions Between The Biophysical And Social Sciences In An Interdisciplinary Sustainability Science Project, Susan Gardner Jun 2014

Bridging The Divide: Tensions Between The Biophysical And Social Sciences In An Interdisciplinary Sustainability Science Project, Susan Gardner

Publications

Interdisciplinary research has gained tremendous popularity in higher education over the past several decades and funding for such efforts through federal agencies has underscored its relevance. In sustainability science, in particular, interdisciplinarity is seen as integral to the research endeavor. However, a paucity of empirical evidence exists regarding the process of interdisciplinary endeavors, particularly those that cross the social-biophysical science divide. The current study incorporated insights over a four-year period from 25 faculty members involved in a large, interdisciplinary effort at one institution of higher education in the United States. Issues of disciplinary status, power, and hierarchy were prevalent in ...


Land Conservation In Northern New England: Historic Trends And Alternative Conservation Features, Spencer Meyer, Christopher Cronan, Robert J. Lilieholm, Michelle Johnson, David Foster Jun 2014

Land Conservation In Northern New England: Historic Trends And Alternative Conservation Features, Spencer Meyer, Christopher Cronan, Robert J. Lilieholm, Michelle Johnson, David Foster

Publications

Protected areas (PAs) are an important component of the global conservation strategy and understanding the past drivers of land protection can inform future conservation planning. Socioeconomic and policy drivers of protection vary through time and space, but a lack of spatio-temporal data limit the ability to conduct retrospective analyses of PAs. We developed a spatio-temporal database covering 90% of area in PAs in northern New England in the U.S. to quantify trends in the extent, rate of increase, ownership characteristics, and level of protection from 1800 to 2010. We found an accelerating rate of protection and an increase in ...


On The Dynamics, Thermodynamics, And Forecast Model Evaluation Of Two Snow-Burst Events In Southern Alberta, Shawn M. Milrad, John R. Gyakum, Kelly Lombardo, Eyad H. Atallah Jun 2014

On The Dynamics, Thermodynamics, And Forecast Model Evaluation Of Two Snow-Burst Events In Southern Alberta, Shawn M. Milrad, John R. Gyakum, Kelly Lombardo, Eyad H. Atallah

Publications

Two high-impact convective snowband events (‘‘snow bursts’’) that affected Calgary, Alberta, Canada, are examined to better understand the dynamics and thermodynamics of heavy snowbands not associated with lake effects or the cold conveyor belt of synoptic-scale cyclones. Such events are typically characterized by brief, but heavy, periods of snow; low visibilities; and substantial hazards to automobile and aviation interests. Previous literature on these events has been limited to a few case studies across North America, including near the leeside foothills of the U.S. Rockies. The large-scale dynamics and thermodynamics are investigated using the National Centers for Environmental Prediction (NCEP ...


Is Biofuel A Feasible Long-Term Chief Energy Source? A Global Perspective, Rajee Olaganathan, Aston Lee, Debra Tong, Mameegate Zheng Jun Cheston, Zack Ho Xuan Yi Jun 2014

Is Biofuel A Feasible Long-Term Chief Energy Source? A Global Perspective, Rajee Olaganathan, Aston Lee, Debra Tong, Mameegate Zheng Jun Cheston, Zack Ho Xuan Yi

Publications

This scientific paper examines the feasibility of officiating biofuels as the future chief energy source of the world. It weighs the pros and cons of the four different generations of biofuels that have been discovered over time, explaining how the raw materials used in each generation determines each individual level of long-term sustainability. It then further analyses both general advantages and disadvantages, comprising of economic, social, health and environmental impacts; giving the reader an unbiased perspective. Few case studies have also been reviewed to better understand the implications of drawing energy from biofuels, as well as the current state of ...


Reduction Of Transportation Greenhouse Gas Emissions To Mitigate Climate Change Impacts, Mary Snow, Richard Snow May 2014

Reduction Of Transportation Greenhouse Gas Emissions To Mitigate Climate Change Impacts, Mary Snow, Richard Snow

Publications

Weather affects almost all modes of transportation in a modern society, and likewise, transportation has an enormous impact on the weather. Transportation greenhouse gas emissions (GHG) impact climate change, which impacts transportation in return. Reduction of transportation impacts on climate change can mitigate the reverse climate change impacts on transportation. This paper examines the relationship between transportation and climate change and establishes prospective solutions to reduce transportation greenhouse gas emission impacts on climate change and mitigate the reverse climate change impacts on transportation.


Three Moving Groups Detected In The Lamost Dr1 Archive, Zhao J. K., Zhao G., Y. Q. Chen, T. D. Oswalt, K. F. Tan, Y. Zhang May 2014

Three Moving Groups Detected In The Lamost Dr1 Archive, Zhao J. K., Zhao G., Y. Q. Chen, T. D. Oswalt, K. F. Tan, Y. Zhang

Publications

We analyze the kinematics of thick disk and halo stars observed by the Large Sky Area Multi-Object Fiber Spectroscopic Telescope. We have constructed a sample of 7993 F, G, and K nearby main-sequence stars (d < 2 kpc) with estimates of position (x, y, z) and space velocity (U, V, W) based on color and proper motion from the Sloan Digital Sky Survey DR9 catalog. Three “phase-space overdensities” are identified in (V,√U2 + 2V 2) with significance levels of σ > 3. Two of them (the Hyades–Pleiades stream and the Arcturus–AF06 stream) have been identified previously. We also ...


Thermospheric Dissipation Of Upward Propagating Gravity Wave Packets, C. J. Heale, J. B. Snively, M. P. Hickey, C. J. Ali May 2014

Thermospheric Dissipation Of Upward Propagating Gravity Wave Packets, C. J. Heale, J. B. Snively, M. P. Hickey, C. J. Ali

Publications

We use a nonlinear, fully compressible, two-dimensional numerical model to study the effects of dissipation on gravity wave packet spectra in the thermosphere. Numerical simulations are performed to excite gravity wave packets using either a time-dependent vertical body forcing at the bottom boundary or a specified initial wave perturbation. Three simulation case studies are performed to excite (1) a steady state monochromatic wave, (2) a spectrally broad wave packet, and (3) a quasi-monochromatic wave packet. In addition, we analyze (4) an initial condition simulation with an isothermal background. We find that, in cases where the wave is not continually forced ...


Very Low Frequency Subionospheric Remote Sensing Of Thunderstorm-Driven Acoustic Waves In The Lower Ionosphere, R. A. Marshall, J. B. Snively May 2014

Very Low Frequency Subionospheric Remote Sensing Of Thunderstorm-Driven Acoustic Waves In The Lower Ionosphere, R. A. Marshall, J. B. Snively

Publications

"We present observations of narrowband subionospheric VLF transmitter signals on 20 March 2001, exhibiting coherent fluctuations of over 1 dB peak to peak. Spectral analysis shows that the fluctuations have periods of 1–4 min and are largely coherent. The subionospheric propagation path of the signal from Puerto Rico to Colorado passes over two regions of convective and lightning activity, as observed by GOES satellite imagery and National Lightning Detection Network lightning data. We suggest that these fluctuations are evidence of acoustic waves launched by the convective activity below, observed in the 80–90 km altitude range to which nighttime ...


Chronic Beryllium Disease: Revealing The Role Of Beryllium Ion And Small Peptides Binding To Hla-Dp2, Marharyta Petukh, Bohua Wu, Shannon Stefl, Nick Smith, David Hyde-Volpe, Li Wang, Emil Alexov May 2014

Chronic Beryllium Disease: Revealing The Role Of Beryllium Ion And Small Peptides Binding To Hla-Dp2, Marharyta Petukh, Bohua Wu, Shannon Stefl, Nick Smith, David Hyde-Volpe, Li Wang, Emil Alexov

Publications

Chronic Beryllium (Be) Disease (CBD) is a granulomatous disorder that predominantly affects the lung. The CBD is caused by Be exposure of individuals carrying the HLA-DP2 protein of the major histocompatibility complex class II (MHCII). While the involvement of Be in the development of CBD is obvious and the binding site and the sequence of Be and peptide binding were recently experimentally revealed [1], the interplay between induced conformational changes and the changes of the peptide binding affinity in presence of Be were not investigated. Here we carry out in silico modeling and predict the Be binding to be within ...