Physical Sciences and Mathematics Commons^™

Calibration Of The Total Carbon Column Observing Network Using Aircraft Profile Data, D. Wunch, G. Toon, P. Wennberg, Steven Wofsy, B. Stephens, M. Fischer, O. Uchino, J. Abshire, P. Bernath, S. Biraud, J.-F. Blavier, C. Boone, K. Bowman, E. Browell, T. Campos, B. Connor, B. Daube, N. Deutscher, Minghui Diao, J. Elkins, C. Gerbig, E. Gottlieb, D. W. Griffith, D. Hurst, R. Jimenez, G. Keppel-Aleks, E. Kort, R. Macatangay, T. Machida, H. Matsueda, F. Moore, I. Morino, S. Park, J. Robinson, C. Roehl, Y. Sawa, V. Sherlock, C. Sweeney, T. Tanaka, M. Zondlo

Faculty Publications, Meteorology and Climate Science

The Total Carbon Column Observing Network (TCCON) produces precise measurements of the column average dry-air mole fractions of CO2, CO, CH4, N2O and H2O at a variety of sites worldwide. These observations rely on spectroscopic parameters that are not known with sufficient accuracy to compute total columns that can be used in combination with in situ measurements. The TCCON must therefore be calibrated to World Meteorological Organization (WMO) in situ trace gas measurement scales. We present a calibration of TCCON data using WMO-scale instrumentation aboard aircraft that measured profiles over four TCCON stations during 2008 and 2009. These calibrations are …

Multilevel Functional Principal Component Analysis For High-Dimensional Data, Vadim Zipunnikov, Brian Caffo, Ciprian Crainiceanu, David M. Yousem, Christos Davatzikos, Brian S. Schwartz

Johns Hopkins University, Dept. of Biostatistics Working Papers

We propose fast and scalable statistical methods for the analysis of hundreds or thousands of high dimensional vectors observed at multiple visits. The proposed inferential methods avoid the difficult task of loading the entire data set at once in the computer memory and use sequential access to data. This allows deployment of our methodology on low-resource computers where computations can be done in minutes on extremely large data sets. Our methods are motivated by and applied to a study where hundreds of subjects were scanned using Magnetic Resonance Imaging (MRI) at two visits roughly five years apart. The original data …

Location And Mechanism Of Very Long Period Tremor During The 2008 Eruption Of Okmok Volcano From Interstation Arrival Times, Matthew M. Haney

CGISS Publications and Presentations

We describe continuous, very long period (VLP) tremor that occurred during the 2008 eruption of Okmok Volcano, Alaska. Due to its low frequency content in band from the 0.2–0.4 Hz, the wave field of the VLP tremor is relatively free of path effects. From continuous recordings of the VLP tremor on 2 three-component broadband and 3 single-component short‐period instruments, we devise a method to locate the epicenter of the tremor based on interstation arrival times computed with cross correlation. We find the epicenter since the vertical and radial components of the VLP tremor wave field are dominated by Rayleigh waves …

Mapping Water Collisions For Interstellar Space Conditions, C.-H. Yang, G. Sarma, J. J. Ter Meulen, D. H. Parker, George C. Mcbane, Laurent Wiesenfeld, A. Faure

Peer Reviewed Articles

We report a joint experimental and theoretical study that directly tests the quality of the potential energy surfaces used to calculate energy changing cross sections of water in collision with helium and molecular hydrogen, at conditions relevant for astrophysics. Fully state-to-state differential cross sections are measured for H₂O-He and H₂O-H₂ collisions at 429 and 575 cm^-1 collision energy, respectively. We compare these differential cross sections with theoretical ones for H₂O+H₂ derived from state-of-the-art potential energy surfaces [P. Valiron et al., J. Chem. Phys. 129, 134306 (2008)] and quantum scattering …

Electronic Structure Based Classification Of Neurotransmitters And Related Drugs, Amrita Jha

Theses and Dissertations

A fundamental understanding of the relationship between structure and activity of neurotransmitters in the human brain is of vital importance for the design targeted drugs. Using density functional theory and hybrid exchange correlation energy functionals we have studied the structure-activity-relationships of some important neurotransmitters and selected drugs by calculating their absolute hardness (η) and absolute electronegativity (χ). A plot of the η- χ diagram allowed us to assign them into three distinct groups, namely, (i) Acetylcholine analogs (positively charged structure), (ii) GABA analogs (zwitterionic structures) and (iii) monoamines. The results suggest that brain stem is chemically soft because of distribution …

Formal [4 + 2] Cycloaddition Of Alkoxy-Substituted Donor-Acceptor Cyclobutanes And Aldehydes Catalyzed By Yb(Otf)3., Mahmoud M Abd Rabo Moustafa, Andrew C Stevens, Ben P Machin, Brian L Pagenkopf

Chemistry Publications

The cycloaddition between 2-alkoxy-1,1-cyclobutane diesters and aromatic, heteroaromatic, or aliphatic aldehydes under Yb(OTf)(3) catalysis generates tetrahydropyrans in high yields with exclusive cis-stereochemistry.

Ytterbium Triflate Catalyzed Synthesis Of Alkoxy-Substituted Donor-Acceptor Cyclobutanes And Their Formal [4 + 2] Cycloaddition With Imines: Stereoselective Synthesis Of Piperidines., Mahmoud M Abd Rabo Moustafa, Brian L Pagenkopf

Chemistry Publications

A new synthesis of 2-alkoxy-1,1-cyclobutane diesters and their first use in dipolar cycloadditions is reported. Both the formation of the donor-acceptor cyclobutanes and their subsequent annulation with in situ formed imines are catalyzed by Yb(OTf)(3). Cyclobutanes with carbon donor groups give piperidines with high trans stereoselectivity.

Polymeric Monolithic Stationary Phases For Capillary Hydrophobic Interaction Chromatography, Yuanyuan Li

Theses and Dissertations

Rigid poly[hydroxyethyl acrylate-co-poly(ethylene glycol) diacrylate] (Poly(HEA-co-PEGDA) monoliths were synthesized inside 75-µm i.d. capillaries by one-step UV-initiated copolymerization using methanol and ethyl ether as porogens. The optimized monolithic column was evaluated for hydrophobic interaction chromatography (HIC) of standard proteins. Six proteins were separated within 20 min with high resolution using a 20 min elution gradient, resulting in a peak capacity of 54. The performance of this monolithic column for HIC was comparable or superior to the performance of columns packed with small particles. Monoliths synthesized solely from PEGDA were also found to show excellent performance in HIC …

Instabilities And Oscillations In Isotropic Active Gels, Shiladitya Banerjee, M. Cristina Marchetti

Physics - All Scholarship

We present a generic formulation of the continuum elasticity of an isotropic crosslinked active gel. The gel is described by a two-component model consisting of an elastic network coupled frictionally to a permeating fluid. Activity is induced by active crosslinkers that undergo an ATP-activated cycle and transmit forces to the network. The on/off dynamics of the active crosslinkers is described via rate equations for unbound and bound motors. For large activity motors yield a contractile instability of the network. At smaller values of activity, the on/off motor dynamics provides an effective inertial drag on the network that opposes elastic restoring …

Simulation Of Groundwater Flow And Effects Of Groundwater Irrigation On Stream Base Flow In The Elkhorn And Loup River Basins, Nebraska, 1895-2055: Phase Two, Jennifer S. Stanton, Steven M. Peterson, Michael N. Fienen

United States Geological Survey: Water Reports and Publications

Regional groundwater-flow simulations for a 30,000-square-mile area of the High Plains aquifer, referred to collectively as the Elkhorn-Loup Model, were developed to predict the effects of groundwater irrigation on stream base flow in the Elkhorn and Loup River Basins, Nebraska. Simulations described the stream-aquifer system from predevelopment through 2005 [including predevelopment (pre-1895), early development (1895–1940), and historical development (1940 through 2005) conditions] and future hypothetical development conditions (2006 through 2033 or 2055). Predicted changes to stream base flow that resulted from simulated changes to groundwater irrigation will aid development of long-term strategies for management of hydrologically connected water supplies.

The …

Take Pride In America In Southern Nevada: Quarterly Progress Report, Period Covering October 5, 2010 – January 4, 2010, Margaret N. Rees

Anti-littering Programs

• The Hector’s Helpers program with the Clark County School District continued curriculum development.
• The team was selected to serve on the litter and recycling work group for Keep Las Vegas Beautiful.
• The team continued to develop the GIS database.
• A total of 12 clean-up events were conducted this quarter.

Molecular Mechanisms Of Persistence Of Mutualistic Bacteria Photorhabdus In The Entomopathogenic Nematode Host, Ruisheng An, Parwinder Grewal

School of Earth, Environmental, and Marine Sciences Faculty Publications and Presentations

Symbioses between microbes and animals are ubiquitous, yet little is known about the intricate mechanisms maintaining such associations. In an emerging mutualistic model system, insect-pathogenic bacteria Photorhabdus and their insect-parasitic nematode partner Heterorhabditis, we found that the bacteria undergo major transcriptional reshaping in the nematode intestine. Besides general starvation mechanisms, the bacteria induce cellular acidification to slow down growth, switch to pentose phosphate pathway to overcome oxidative stress and nutrition limitation, and shed motility but develop biofilm to persist in the nematode intestine until being released into the insect hemolymph. These findings demonstrate how the symbiotic bacteria reduce their …

Unidirectional Nonlinear Pt-Symmetric Optical Structures, Hamidreza Ramezani, Tsampikos Kottos, Ramy El-Ganainy, Demetrios N. Christodoulides

Ramy El-Ganainy

We show that nonlinear optical structures involving a balanced gain-loss profile can act as unidirectional optical valves. This is made possible by exploiting the interplay between the fundamental symmetries of parity (P) and time (T), with optical nonlinear effects. This unidirectional dynamics is specifically demonstrated for the case of an integrable PT -symmetric nonlinear system.

Ferroelectricity In Non-Stoichiometric Srtio3 Films Studied By Ultraviolet Raman Spectroscopy, Dmitri A. Tenne, A. K. Farrar

Physics Faculty Publications and Presentations

Homoepitaxial Sr_1+xTiO_3+δ films with -0.2 ≤ x ≤ 0.25 grown by reactive molecular-beam epitaxy on SrTiO₃ (001) substrates have been studied by ultraviolet Raman spectroscopy. Non-stoichiometry for strontium- deficient compositions leads to the appearance of strong first-order Raman scattering at low temperatures, which decreases with increasing temperature and disappears at about 350 K. This indicates the appearance of a spontaneous polarization with a paraelectric-to-ferroelectric transition temperature above room temperature. Strontium-rich samples also show a strong first-order Raman signal, but the peaks are significantly broader and exhibit a less pronounced temperature dependence, indicating a stronger contribution …

Take Pride In America In Southern Nevada: Quarterly Progress Report, Period Covering July 5, 2010 – October 4, 2010, Margaret N. Rees

Anti-littering Programs

• The street team portion of the media campaign was completed.
• The Hector’s Helpers program with the Clark County School District continued curriculum development.
• The team was selected to serve on the litter and recycling work group for Keep Las Vegas Beautiful.
• The team continued to develop the GIS database.
• A total of five clean-up events were conducted this quarter.

First Year Investigation Of Gravity Waves And Temperature Variability Over The Andes, Jonathan Pugmire, Neal R. Criddle, Michael J. Taylor, Dominique Pautet, Yucheng Zhao

Graduate Student Presentations

The Andes region is an excellent natural laboratory for investigating gravity wave influences on the Upper Mesospheric and Lower Thermospheric (MLT) dynamics: during the summer months the dominant gravity waves result from deep convection arising from severe thunderstorms over the continent to the east. In winter this convective activity is expected to be replaced by strong orographic forcing due to intense prevailing zonal winds blowing eastward from the Pacific Ocean and suddenly encountering the towering Andes mountain range (6000m). This creates large amplitude mountain waves that have been measured well into the stratosphere and most recently penetrate occasionally into the …

One-Dimensional Wave Equations Defined By Fractal Laplacians, John Fun-Choi Chan, Sze-Man Ngai, Alexander Teplyaev

Sze-Man Ngai

We study one-dimensional wave equations defined by a class of fractal Laplacians. These Laplacians are defined by fractal measures generated by iterated function systems with overlaps. We prove the existence and uniqueness of weak solutions. We also study numerical computations of the solutions and prove the convergence of the approximation scheme. This is a joint work with John F. Chan and Alexander Teplyaev.

Efficient Synthesis And Conformational Investigations Of Cis-Pentacenediols, Jinyue Jiang, Charles E. Schiaffo, Chris P. Schwartz, Yong Pei, Joseph J. Dumais, Xiao Cheng Zeng, Patrick Dussault, Li Tan

Patrick Dussault Publications

Diisobutylaluminum hydride is utilized to reduce pentacene-6,13-diones to the corresponding diols, useful precursors to functionalized pentacenes. This pathway is mild and efficient, and produces the cis-diols as major products. Further, we found the cis-diols adopt endo conformation, which cannot flip to the exo conformation under ambient conditions. Due to the cis and endo orientation, the cis-diols can be potential bidentates in catalysis, molecular propellers, and optoelectronic devices.

The Waterfalls Of Kauai, Hawaii, Darryll T. Pederson

Department of Earth and Atmospheric Sciences: Faculty Publications

Everyone enjoys the sounds and sights of a tropical waterfall. They are the setting for romantic and action packed movies. Fantasy Island used Wailua Falls on Kauai to open their weekly TV series. From a different viewpoint waterfall origin and evolution has been attributed to a wide range of geologic processes. The Hawaiian Island's waterfalls and amphitheater-headed valleys have been cited by many as equivalent to similar features seen on Mars. After a number of years of studying these features on Kauai, I offer the following thoughts and observations about Kauai's waterfalls and amphitheater-headed valleys.

Continental Warming Preceding The Paleocene–Eocene Thermal Maximum, Ross Secord, Philip D. Gingerich, Kyger C. Lohmann, Kenneth G. Macleod

Department of Earth and Atmospheric Sciences: Faculty Publications

Marine and continental records show an abrupt negative shift in carbon isotope values at ~55.8 Myr ago. This carbon isotope excursion (CIE) is consistent with the release of a massive amount of isotopically light carbon into the atmosphere and was associated with a dramatic rise in global temperatures termed the Paleocene–Eocene thermal maximum (PETM). Greenhouse gases released during the CIE, probably including methane, have often been considered the main cause of PETM warming. However, some evidence from the marine record suggests that warming directly preceded the CIE, raising the possibility that the CIE and PETM may have been linked to …

Virginia Wetlands Report Vol. 25, No. 2, Virginia Institute Of Marine Science, Center For Coastal Resources Management

Virginia Wetlands Reports

CCRM Living Shorelines Website Update

Water Current, Volume 42, No. 4, Fall 2010

Water Current Newsletter

Permanganate Candles Clean Contamination at Former Cozad Landfill

Free Water and Natural Resources Lectures Begin Jan. 19

Water Center has Busy and Prosperous Fall; Dvorak to Return from Czech

Meet the Faculty: Greg Kruger, Ph.D., Christ L. Thompson

2011 Water Tour Focuses on Ogallala Aquifer

New Web Portal Focuses on Republican River Basin

The Center Pivot Water Conservation Project

The Eternal Flame and the Grandfather Clock

A Trio of Fall Events

WRAP Meets with VCs Green and Paul; Reviews Projects

NSF Awards Grants to Study Dimensions of Earth’s Biodiversity

Saving Space And Time Using Index Merging, Lubomir Stanchev, Grant Weddell

Computer Science and Software Engineering

Managing digital information is an integral part of our society. Efficient access to data is supported through the use of indices. Although indices can reduce the cost of answering queries, they have two significant drawbacks: they take additional storage space and their maintenance can become a bottleneck. We address these challenges by introducing search data structures that reduce the need for storing redundant data among indices. Our experimental results with the main-memory version of these data structures show that our approach can reduce by half the storage space and can improve performance, where the highest performance improvement is achieved for …

Solving The Low Dimensional Smoluchowski Equation With A Singular Value Basis Set, Gregory E. Scott, Martin Gruebele

Chemistry and Biochemistry

Reaction kinetics on free energy surfaces with small activation barriers can be computed directly with the Smoluchowski equation. The procedure is computationally expensive even in a few dimensions. We present a propagation method that considerably reduces computational time for a particular class of problems: when the free energy surface suddenly switches by a small amount, and the probability distribution relaxes to a new equilibrium value. This case describes relaxation experiments. To achieve efficient solution, we expand the density matrix in a basis set obtained by singular value decomposition of equilibrium density matrices. Grid size during propagation is reduced from (100–1000) …

Nanopod Formation Through Gold Nanoparticle Templated And Catalyzed Cross-Linking Of Polymers Bearing Pendant Propargyl Ethers, Ke Zhang, Joshua I. Cutler, Jian Zhang, Dan Zheng, Evelyn Auyeung, Chad A. Mirkin

Chemistry Department: Faculty Publications

A novel method for synthesizing polymer nanopods from a linear polymer bearing pendant propargyl ether groups, using gold nanoparticles as both the template and the catalyst for the crosslinking reaction, is reported. The transformations involved in the cross-linking process are unprecedented on the surface of a gold particle. A tentative cross-linking mechanism is proposed.

Includes Supporting Information.

Oga Inhibition By Glcnac-Selenazoline, E. J. Kim, D. C. Love, E. Darout, M. Abdo, B. Rempel, S. G. Withers, Paul R. Rablen, J. A. Hanover, S. Knapp

Chemistry & Biochemistry Faculty Works

The title compound, which differs from the powerful O-GlcNAcase (OGA) inhibitor GlcNAc-thiazoline only at the chalcogen atom (Se for S), is a much weaker inhibitor in a direct OGA assay. In human cells, however, the selenazoline shows comparable ability to induce hyper-O-GlcNAc-ylation, and the two show similar reduction of insulin-stimulated translocation of glucose transporter 4 in differentiated 3T3 adipocytes. (C) 2010 Elsevier Ltd. All rights reserved.

The Amazon Frontier Of Land-Use Change: Croplands And Consequences For Greenhouse Gas Emissions, Gillian L. Galford, Jerry Melillo, John F. Mustard, Carlos E.P. Cerri, Carlos C. Cerri

Rubenstein School of Environment and Natural Resources Faculty Publications

The Brazilian Amazon is one of the most rapidly developing agricultural frontiers in the world. The authors assess changes in cropland area and the intensification of cropping in the Brazilian agricultural frontier state of Mato Grosso using remote sensing and develop a greenhouse gas emissions budget. The most common type of intensification in this region is a shift from single-to double-cropping patterns and associated changes in management, including increased fertilization. Using the enhanced vegetation index (EVI) from the Moderate Resolution Imaging Spectroradiometer (MODIS) sensor, the authors created a green-leaf phenology for 2001-06 that was temporally smoothed with a wavelet filter. …

Spatio-Temporal Coupling Of Random Electromagnetic Pulses Interacting With Reflecting Gratings, Min Yao, Yangjian Cai, Olga Korotkova, Qiang Lin, Zhaoying Wang

Physics Articles and Papers

Matrix optics is applied to a class of random, in time and space, electromagnetic pulsed beam-like (REMPB) radiation interacting with linear optical elements. A 66 order matrix describing transformation of a six-dimensional state vector including four spatial and two temporal positions within the field is used to derive conditions for spatio-temporal coupling. An example is included which deals with a spatio-temporal coupling in a typical REMPB on reflection from a reflecting grating. Electromagnetic nature of such interaction is explored via considering dependence of the degree of polarization of the reflected REMPB on its source and on the structure of the …

Ebec Phase Ii Wind Energy Project Feasibility Study: Asa Project 10-060, Final Report, Applied Science Associates, Inc.

East Bay Energy Consortium Documents

Subsequent to the Phase I preliminary wind energy feasibility and siting study EBEC contracted again with ASA to perform a Phase II study with the scope of performing a detailed feasibility study of developing a project at the Tiverton site. The detailed study, presented herein, evaluated the project size and layout options, siting considerations, procurement and development considerations, ownership structures, financing opportunities, and legislation considerations. The results are presented as four different options for EBEC to act as owner, developer and operator, evaluating the associated development cost and potential revenue streams as well as a third party developer owned and …

Cosmology With Torsion: An Alternative To Cosmic Inflation, Nikodem Poplawski

Physics Faculty Publications

We propose a simple scenario which explains why our Universe appears spatially flat, homogeneous and isotropic. We use the Einstein–Cartan–Kibble–Sciama (ECKS) theory of gravity which naturally extends general relativity to include the spin of matter. The torsion of spacetime generates gravitational repulsion in the early Universe filled with quarks and leptons, preventing the cosmological singularity: the Universe expands from a state of minimum but finite radius. We show that the dynamics of the closed Universe immediately after this state naturally solves the flatness and horizon problems in cosmology because of an extremely small and negative torsion density parameter,Ω_S≈− …