Physical Sciences and Mathematics Commons^™

Highly Variable Recurrence Of Tsunamis In The 7,400 Years Before The 2004 Indian Ocean Tsunami, Charles M. Rubin, Benjamin P. Horton, Kerry Sieh, Jessica E. Pilarczyk, Patrick Daly, Nazli Ismail, Andrew C. Parnell

Faculty Publications

The devastating 2004 Indian Ocean tsunami caught millions of coastal residents and the scientific community off-guard. Subsequent research in the Indian Ocean basin has identified prehistoric tsunamis, but the timing and recurrence intervals of such events are uncertain. Here we present an extraordinary 7,400 year stratigraphic sequence of prehistoric tsunami deposits from a coastal cave in Aceh, Indonesia. This record demonstrates that at least 11 prehistoric tsunamis struck the Aceh coast between 7,400 and 2,900 years ago. The average time period between tsunamis is about 450 years with intervals ranging from a long, dormant period of over 2,000 years, to …

The Potential Effects Of Percolating Snowmelt On Palynological Records From Firn And Glacier Ice, Michael E. Ewin, Carl A. Reese, Matthew A. Nolan

Faculty Publications

The effects of meltwater percolation on pollen in snow, firn and glacial ice are not fully understood and currently hamper the use of pollen in ice-core studies of paleoclimate. Several studies have suggested that, due to grain size, pollen is not mobilized by meltwater transport. However, these findings contradict many ice-core pollen studies that show pollen concentrations in snow and firn are much higher than concentrations found in the ice layers they eventually form. This study addresses one aspect of this question by investigating whether meltwater percolation can effectively transport pollen within a snowpack. We used nine Styrofoam coolers filled …

List-Distinguishing Cartesian Products Of Cliques, Michael Ferrara, Zoltan Füredi, Sogol Jahanbekam, Paul Wenger

Faculty Publications

The distinguishing number of a graph G, denoted D(G), is the minimum number of colors needed to produce a coloring of the vertices of G so that every nontrivial isomorphism interchanges vertices of different colors. A list assignment L on a graph G is a function that assigns each vertex of G a set of colors. An L-coloring of G is a coloring in which each vertex is colored with a color from L(v). The list distinguishing number of G, denoted Dℓ(G) is the minimum k such that every list assignment L that assigns a list of size at least …

The Sluggs Survey: Dark Matter Fractions At Large Radii And Assembly Epochs Of Early-Type Galaxies From Globular Cluster Kinematics, Adebusola Alabi, Duncan Forbes, Aaron Romanowsky, Jean Brodie, Jay Strader, Joachim Janz, Christopher Usher, Lee Spitler, Sabine Bellstedt, Anna Ferré-Mateu

Faculty Publications

We use globular cluster kinematics data, primarily from the SAGES Legacy Unifying Globulars and GalaxieS (SLUGGS) survey, to measure the dark matter fraction (fDM) and the average dark matter density (〈ρDM〉) within the inner 5 effective radii (Re) for 32 nearby early-type galaxies (ETGs) with stellar mass log (M*/M⊙) ranging from 10.1 to 11.8. We compare our results with a simple galaxy model based on scaling relations as well as with cosmological hydrodynamical simulations where the dark matter profile has been modified through various physical processes. We find a high fDM (≥0.6) within 5 Re in most of our sample, …

Equity Of Success In Clasp Courses At Uc Davis, Cassandra Paul, David Webb, Mary Chessey, Wendell Potter

Faculty Publications

We have recently described the reformed introductory physics course, Collaborative Learning through Active Sense-Making in Physics (CLASP), for bioscience students at UC Davis and argued that the course was more successful than its predecessor (Physics 5) by several measures. Now we examine the effects of these courses for different student ethnic groups. We find that, compared to Physics 5, students of most ethnic backgrounds were more successful in CLASP. We also find that students from ethnic groups underrepresented in STEM who took the CLASP course were more likely to graduate as STEM majors. We discuss possible features of CLASP that …

In-Beam Γ-Ray Spectroscopy Studies Of Medium-Spin States In The Odd-Odd Nucleus 186Re, David A. Matters, F. G. Kondev, N. Aoi, Y. Ayyad, A. P. Byrne, M. P. Carpenter, J. Carroll, C. J. Chiara, P. M. Davidson, G. D. Dracoulis, Y. D. Fang, C. R. Hoffmann, R. O. Hughes, E. Ideguchi, R. V. F. Janssens, S. Kanaya, B. P. Kay, T. Kibedi, G. J. Lane, T. Lauritsen, John W. Mcclory, P. Nieminen, S. Noji, A. Odahara, H. J. Ong, A. E. Stuchbery, D. T. Tran, H. Watanabe, A. N. Wilson, Y. Yamamoto, S. Zhu

Faculty Publications

Excited states in ¹⁸⁶Re with spins up to J=12ℏ were investigated in two separate experiments using 186W(d,2n) reactions at beam energies of 12.5 and 14.5 MeV. Two- and threefold γ-ray coincidence data were collected using the CAESAR and CAGRA spectrometers, respectively, each composed of Compton-suppressed high-purity germanium detectors. Analysis of the data revealed rotational bands built on several two-quasiparticle intrinsic states, including a long-lived K^π=(8⁺) isomer. Configuration assignments were supported by an analysis of in-band properties, such as |gK−gR| values. The excitation energies of the observed intrinsic states were compared with results from multi-quasiparticle blocking …

Changes In Substrate Availability Drive Carbon Cycle Response To Chronic Warming, Grace Pold, A. Stuart Grandy, Jerry M. Melillo, Kristen M. Deangelis

Faculty Publications

As earth's climate continues to warm, it is important to understand how the capacity of terrestrial ecosystems to retain carbon (C) will be affected. We combined measurements of microbial activity with the concentration, quality, and physical accessibility of soil carbon to microorganisms to evaluate the mechanisms by which more than two decades of experimental warming has altered the carbon cycle in a Northeast US temperate deciduous forest. We found that concentrations of soil organic matter were reduced in both the organic and mineral soil horizons. The molecular composition of the carbon was altered in the mineral soil with significant reductions …

Growth And Magnetooptical Properties Of Anisotropic Tbf3 Single Crystals, Uygun V. Valiev, Denis N. Karimov, Gary W. Burdick, Rakhim Rakhimov, Vasiliy O. Pelenovich, Dejun Fu

Faculty Publications

The present paper investigates the Faraday effect and absorption and luminescence spectra of single-crystal TbF₃ measured at 90 K and 300 K. The optical-quality single-phase TbF₃ crystals (structural type β-YF3) were grown by the Bridgman technique. Faraday rotation angles were measured at remagnetization along the [100] crystallographic axis. Low temperature optical measurements were carried out along the [100] axis. “Quasi-doublet” sublevels with energy at 0 cm^-1, 65 cm^-1 and 190 cm^-1, and also a singlet sublevel with energy at 114 cm^-1 located in the ground 7F6 multiplet were determined from the …

An Ensemble Multilabel Classification For Disease Risk Prediction, Runzhi Li, Wei Liu, Yusong Lin, Hongling Zhao, Chaoyang Zhang

Faculty Publications

It is important to identify and prevent disease risk as early as possible through regular physical examinations. We formulate the disease risk prediction into a multilabel classification problem. A novel Ensemble Label Power-set Pruned datasets Joint Decomposition (ELPPJD) method is proposed in this work. First, we transform the multilabel classification into a multiclass classification. Then, we propose the pruned datasets and joint decomposition methods to deal with the imbalance learning problem. Two strategies size balanced (SB) and label similarity (LS) are designed to decompose the training dataset. In the experiments, the dataset is from the real physical examination records. We …

The Sluggs Survey: Using Extended Stellar Kinematics To Disentangle The Formation Histories Of Low-Mass S0 Galaxies, Sabine Bellstedt, Duncan Forbes, Caroline Foster, Aaron Romanowsky, Jean Brodie, Nicola Pastorello, Adebusola Alabi, Alexa Villaume

Faculty Publications

We utilize the DEIMOS instrument on the Keck telescope to measure the wide-field stellar kinematics of early-type galaxies as part of the SAGES Legacy Unifying Globulars and GalaxieS (SLUGGS) survey. In this paper, we focus on some of the lowest stellar mass lenticular galaxies within this survey, namely NGC 2549, NGC 4474, NGC 4459 and NGC 7457, performing detailed kinematic analyses out to large radial distances of ∼2–3 effective radii. For NGC 2549, we present the first analysis of data taken with the SuperSKiMS (Stellar Kinematics from Multiple Slits) technique. To better probe kinematic variations in the outskirts of the …

Relaxation Of Microwave Nonlinearity In A Cuprate Superconducting Resonator, Richard A. Huizen, Sean L. Hamilton, Geoffrey T. Lenters, Stephen K. Remillard

Faculty Publications

The second- and third-order nonlinear microwave response of a superconducting YBa2Cu3O7 thin-film resonator was synchronously measured using three input tones. This technique permits the local measurement, and hence mapping, of intermodulation distortion inside the resonator. Second- and third-order IMD measured with a fixed probe relaxed in remarkably different ways after the removal of a static magnetic field. The second-order IMD relaxed by two different magnetic processes, a fast process that appears related to bulk remanent magnetization and a slow process that fits the description of Bean and Livingston. The third-order IMD relaxes by only one process that is distinct from …

Conquering Worrisome Word Problems – Algebra Success, Vicki-Lynn Holmes, Karla Spence, Jane Finn, Shelia Mcgee Ingram, Libbey Horton

Faculty Publications

High school students can struggle with word problems in upper level math classes. Causes for this struggle could include lower reading comprehension, limited mathematic vocabulary, and difficulty changing words to algebraic expressions. This article proposes three techniques to help teachers instruct these struggling students that include (a) organization by difficulty of comprehension and computation (b) scaffolding and (c) utilizing the Explain, Practice and Assess (EPA) strategy.

Measuring The Reflection Matrix Of A Rough Surface, Kenneth W. Burgi, Michael A. Marciniak, Mark E. Oxley, Stephen E. Nauyoks

Faculty Publications

Phase modulation methods for imaging around corners with reflectively scattered light required illumination of the occluded scene with a light source either in the scene or with direct line of sight to the scene. The RM (reflection matrix) allows control and refocusing of light after reflection, which could provide a means of illuminating an occluded scene without access or line of sight. Two optical arrangements, one focal-plane, the other an imaging system, were used to measure the RM of five different rough-surface reflectors. Intensity enhancement values of up to 24 were achieved. Surface roughness, correlation length, and slope were examined …

Rapid Reversible Borane To Boryl Hydride Exchange By Metal Shuttling On The Carborane Cluster Surface, Bennett J. Eleazer, Mark D. Smith, Alexey A. Popov, Dmitry V. Peryshkov

Faculty Publications

In this work, we introduce a novel concept of a borane group vicinal to a metal boryl bond acting as a supporting hemilabile ligand in exohedrally metalated three-dimensional carborane clusters. The (POBOP)Ru(Cl)(PPh3) pincer complex (POBOP ¼ 1,7-OP(i-Pr)2-m-2-carboranyl) features extreme distortion of the two-center-two-electron Ru–B bond due to the presence of a strong three-centertwo-electron B–H/Ru vicinal interaction. Replacement of the chloride ligand with a hydride afforded the (POBOP)Ru(H)(PPh3) pincer complex, which possesses B–Ru, B–H/Ru, and Ru–H bonds. This complex was found to exhibit a rapid exchange between hydrogen atoms of the borane and the terminal hydride through metal center shuttling between …

Preferential Binding Effects On Protein Structure And Dynamics Revealed By Coarse-Grained Monte Carlo Simulation, Ras B. Pandey, D.L. Jacobs, Barry L. Farmer

Faculty Publications

The effect of preferential binding of solute molecules within an aqueous solution on the structure and dynamics of the histone H3.1 protein is examined by a coarse-grained Monte Carlo simulation. The knowledge-based residue-residue and hydropathy-index-based residue-solvent interactions are used as input to analyze a number of local and global physical quantities as a function of the residue-solvent interaction strength (f). Results from simulations that treat the aqueous solution as a homogeneous effective solvent medium are compared to when positional fluctuations of the solute molecules are explicitly considered. While the radius of gyration (R_g) of the …

Strong Linkages Between Surface And Deep-Water Dissolved Organic Matter In The East/Japan Sea, Tae-Hoon Kim, Guebuem Kim, Yuan Shen, Ronald Benner

Faculty Publications

Vertical and horizontal distributions of total dissolved amino acids (TDAAs), dissolved organic carbon (DOC), and dissolved organic nitrogen (DON) were measured in the East/Japan Sea (EJS). The euphotic zone of this sea is N-limited, and the N : P ratio is ∼ 13 below 200 m depth. Elevated TDAA concentrations (137 ± 34 nM) and DOC-normalized yields (0.8 ± 0.2 % of DOC) were observed in deep waters ( ≥  1000 m) of the EJS and compared with those in the deep North Pacific Ocean. Significantly high TDAA concentrations and yields were observed in a region of deep-water formation, indicating …

On The Origin Of Energy: Metaphors And Manifestations As Resources For Conceptualizing And Measuring The Invisible, Imponderable, Benedikt Harrer

Faculty Publications

This article explores the origins of metaphorical language to describe energy by reviewing the historical development of the concept by physicists since the early 19th century. In addition to examples of historical and contemporary use of metaphors in academic writing, observable manifestations of energy are identified as the origin of energy “forms.” The historical- philosophical review and presentation of examples from contemporary physics literature contribute a disciplinary foundation to recent claims about the productiveness of physics learners’ use of metaphors and indicators to describe energy.

Modeled Co2 Emissions From Coastal Wetland Transitions To Other Land Uses: Tidal Marshes, Mangrove Forests, And Seagrass Beds, Catherine E. Lovelock, James W. Fourqurean, James T. Morris

Faculty Publications

The sediments of coastal wetlands contain large stores of carbon which are vulnerable to oxidation once disturbed, resulting in high levels of CO2 emissions that may be avoided if coastal ecosystems are conserved or restored. We used a simple model to estimate CO2 emissions from mangrove forests, seagrass beds, and tidal marshes based on known decomposition rates for organic matter in these ecosystems under either oxic or anoxic conditions combined with assumptions of the proportion of sediment carbon being deposited in either oxic or anoxic environments following a disturbance of the habitat. Our model found that over 40 years after …

Gallium Vacancies In Β-Ga2O3 Crystals, Brant E. Kananen [*], Larry E. Halliburton, K. T. Stevens, G. K. Foundos

Faculty Publications

The gallium vacancy, an intrinsic acceptor, is identified in β-Ga₂O₃ using electron paramagnetic resonance (EPR). Spectra from doubly ionized (V²⁻_Ga) and singly ionized (V⁻_Ga) gallium vacancies are observed at room temperature, without photoexcitation, after an irradiation with high-energy neutrons. The V²⁻_Ga centers (with S = 1/2) have a slight angular variation due to a small anisotropy in the g matrix (principal values are 2.0034, 2.0097, and 2.0322). The V²⁻_Ga centers also exhibit a resolved hyperfine structure due to equal and nearly isotropic interactions with the …

The Hi Content Of Isolated Ultra-Diffuse Galaxies: A Sign Of Multiple Formation Mechanisms?, E. Papastergis, E. Adams, Aaron Romanowsky

Faculty Publications

We report on the results of radio observations in the 21 cm emission line of atomic hydrogen (HI) of four relatively isolated ultra-diffuse galaxies (UDGs): DGSAT I, R-127-1, M-161-1, and SECCO-dI-2. Our Effelsberg observations resulted in non-detections for the first three UDGs, and a clear detection for the last. DGSAT I, R-127-1, and M-161-1 are quiescent galaxies with gas fractions that are much lower than those of typical field galaxies of the same stellar mass. On the other hand, SECCO-dI-2 is a star forming gas-rich dwarf, similar to two other field UDGs that have literature HI data: SECCO-dI-1 and UGC …

Digital Hegemonies: The Localness Of Search Engine Results, Andrea Ballatore, Mark Graham, Shilad Sen

Faculty Publications

Every day, billions of Internet users rely on search engines to find information about places to make decisions about tourism, shopping, and countless other economic activities. In an opaque process, search engines assemble digital content produced in a variety of locations around the world and make it available to large cohorts of consumers. Although these representations of place are increasingly important and consequential, little is known about their characteristics and possible biases. Analyzing a corpus of Google search results generated for 188 capital cities, this article investigates the geographic dimension of search results, focusing on searches such as “Lagos” and …

Analysis Of Beam Deflection Measurements In The Presence Of Linear Absorption, Manuel R. Ferdinandus, Jennifer Reed, Kent L. Averett, F. Kenneth Hopkins, Augustine Urbas

Faculty Publications

We develop a series of analytical approximations allowing for rapid extraction of the nonlinear parameters from beam deflection measurements. We then apply these approximations to the analysis of cadmium silicon phosphide and compare the results against previously published parameter extraction methods and find good agreement for typical experimental conditions.

Phospholipase Dζ Enhances Diacylglycerol Flux Into Triacylglycerol, Wenyu Yang, Geliang Wang, Jia Li, Philip D. Bates, Xuemin Wang, Doug K. Allen

Faculty Publications

Plant seeds are the primary source of triacylglycerols (TAG) for food, feed, fuel, and industrial applications. As TAG is produced from diacylglycerol (DAG), successful engineering strategies to enhance TAG levels have focused on the conversion of DAG to TAG. However, the production of TAG can be limited by flux through the enzymatic reactions that supply DAG. In this study, two Arabidopsis phospholipase D_ζ genes (AtPLD_ζ1 and AtPLD_ζ2) were coexpressed in Camelina sativa to test whether the conversion of phosphatidylcholine to DAG impacts TAG levels in seeds. The resulting transgenic plants produced 2% to 3% more TAG …

Kinetics Of High Pressure Argon-Helium Pulsed Gas Discharge, Daniel J. Emmons, David E. Weeks

Faculty Publications

Simulations of a pulsed direct current discharge are performed for a 7% argon in helium mixture at a pressure of 270 Torr using both zero- and one-dimensional models. Kinetics of species relevant to the operation of an optically pumped rare-gas laser are analyzed throughout the pulse duration to identify key reaction pathways. Time dependent densities, electron temperatures, current densities, and reduced electric fields in the positive column are analyzed over a single 20 μs pulse, showing temporal agreement between the two models. Through the use of a robust reaction rate package, radiation trapping is determined to play a key role …

Why Teach Science? Helping Teacher Candidates Frame Instructional Decision Making From Moral And Ethical Perspectives, Grinell Smith, Colette Rabin

Faculty Publications

This qualitative research project’s overarching goal was to explore ways to help primary grade teacher candidates (re)kindle a conception of teaching as a moral enterprise involving ethical choices and enactment of one’s values. In the context of a science methods course, we explored the research question: What happens to the commitments toward science instruction of pre-service elementary teachers when we help them view science instruction as an act of caring? Our findings suggest that for many, this approach helped students take a moral stance, articulate an ethical position regarding educational issues, and use these perspectives to inform decision-making at the …

Detection Of Supermassive Black Holes In Two Virgo Ultracompact Dwarf Galaxies, Christopher Ahn, Anil Seth, Mark Den Brok, Jay Strader, Holger Baumgardt, Remco Van Den Bosch, Igor Chilingarian, Matthias Frank, Michael Hilker, Richard Mcdermid, Steffen Mieske, Aaron Romanowsky, Lee Spitler, Jean Brodie, Nadine Neumayer, Jonelle Walsh

Faculty Publications

No abstract provided.

Time Lags Associated With Effects Of Oceanic Conditions On Seabird Breeding In The Salish Sea Region Of The Northern California Current System, Rashida S. Smith, Lynelle M. Weldon, James L. Hayward, Shandelle M. Henson

Faculty Publications

No abstract provided.

Functional Photosystem I Maintains Proper Energy Balance During Nitrogen Depletion In Chlamydomonas Reinhardtii, Promoting Triacylglycerol Accumulation, Mahmoud Gargouri, Philip D. Bates, Jeong-Jin Park, Helmut Kirchhoff, David R. Gang

Faculty Publications

Background

Nutrient deprivation causes significant stress to the unicellular microalga, Chlamydomonas reinhardtii, which responds by significantly altering its metabolic program. Following N deprivation, the accumulation of starch and triacylglycerols (TAGs) is significantly altered following massive reprogramming of cellular metabolism. One protein that was found to change dramatically and early to this stress was TAB2, a photosystem I (PSI) translation initiation factor, whose transcript and protein levels increased significantly after only 30 min of N deprivation. A detailed physiological and omics-based analysis of an insertional mutant of Chlamydomonas with reduced TAB2 function was conducted to determine what role the functional …

Periodic Traveling Interfacial Hydroelastic Waves With Or Without Mass, Benjamin F. Akers, David M. Ambrose, David W. Sulon

Faculty Publications

We study the motion of an interface between two irrotational, incompressible fluids, with elastic bending forces present; this is the hydroelastic wave problem. We prove a global bifurcation theorem for the existence of families of spatially periodic traveling waves on infinite depth. Our traveling wave formulation uses a parameterized curve, in which the waves are able to have multi-valued height. This formulation and the presence of the elastic bending terms allows for the application of an abstract global bifurcation theorem of "identity plus compact" type. We furthermore perform numerical computations of these families of traveling waves, finding that, depending on …

An Approach To Robust Homing With Stereovision, Fuqiang Fu, Damian Lyons

Faculty Publications

Visual Homing is a bioinspired approach to robot navigation which can be fast and uses few assumptions. However, visual homing in a cluttered and unstructured outdoor environment offers several challenges to homing methods that have been developed for primarily indoor environments. One issue is that any current image during homing may be tilted with respect to the home image. The second is that moving through a cluttered scene during homing may cause obstacles to interfere between the home scene and location and the current scene and location. In this paper, we introduce a robust method to improve a previous developed …