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2015

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Articles 1711 - 1740 of 12617

Full-Text Articles in Physical Sciences and Mathematics

Successful Foundation Preparations In Karst Bedrock Of The Masonry Section Of Wolf Creek Dam, David M. Robison Oct 2015

Successful Foundation Preparations In Karst Bedrock Of The Masonry Section Of Wolf Creek Dam, David M. Robison

Sinkhole Conference 2015

Extensive foundation preparations during construction of the Wolf Creek Dam concrete masonry section precluded the need for additional rehabilitation to mitigate seepage through karstic limestone bedrock. Wolf Creek Dam on the Cumberland River in southern Kentucky has become well known for karst related seepage issues underneath the embankment section, and yet has had little to no seepage issues associated with the concrete masonry portion of the dam. Post-construction efforts to control seepage underneath the embankment began in 1967 and 1968. Emergency grouting commenced and continued through 1970. Between 1975 and 1979 a more permanent solution of a concrete diaphragm cut-off …

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Pre-Construction Rock Treatment And Soil Modification Program Using Low Mobility Grout To Mitigate Future Sinkhole Development In A 2,787.1 Square Meter (30,000 Sf) Maintenance Facility, Steven W. Shifflett Oct 2015

Pre-Construction Rock Treatment And Soil Modification Program Using Low Mobility Grout To Mitigate Future Sinkhole Development In A 2,787.1 Square Meter (30,000 Sf) Maintenance Facility, Steven W. Shifflett

Sinkhole Conference 2015

The US Army required construction of a 2,787.1 square meters (30,000 sf) maintenance facility supported on shallow foundations at the Fort Campbell Military Installation. During the subsurface investigation a seven foot air-filled void was encountered in the bedrock within the building footprint. Electrical Resistivity Imaging (ERI) was conducted in an attempt to determine the lateral extent of the encountered void and to establish the general prevalence of karst features at the site. Due to uncertainty in the subsurface conditions, a rock treatment and soil modification program was developed which consisted of a series of targeted exploratory grout holes advanced in …

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Monitoring The Threat Of Sinkhole Formation Under A Portion Of Us 18 In Cerro Gordo County, Iowa Using Tdr Measurements, Kevin O'Connor, Matthew Trainum Oct 2015

Monitoring The Threat Of Sinkhole Formation Under A Portion Of Us 18 In Cerro Gordo County, Iowa Using Tdr Measurements, Kevin O'Connor, Matthew Trainum

Sinkhole Conference 2015

Sinkhole formation is a common occurrence in northeast Iowa, and U.S. 18 in Cerro Gordo County was constructed over an area where sinkhole formation had only been locally known. It had not been recorded or identified in the Iowa DNR database at the time. Since 2004, sinkholes have developed along the right of way. Geophysical surveys contributed very little in the identifying the cause. However a Soil Survey (drilling program) identified numerous voids within carbonate bedrock. The soil borings indicated that shale overlying the carbonate rock has been removed/eroded, and resulted in the development of a karst subsurface through the …

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Concepts For Geotechnical Investigation In Karst, Joseph A. Fischer, Joseph J. Fischer Oct 2015

Concepts For Geotechnical Investigation In Karst, Joseph A. Fischer, Joseph J. Fischer

Sinkhole Conference 2015

There seems to be a lack of recognition in the literature that addresses the variety of karst in the United States of America and some of its offshore territories. For example, there are the well-known solutioned carbonates of Florida and the Caribbean, but there are also the somewhat older, harder carbonates of St. Croix, U.S.V.I. Even Florida’s recently deposited karst varies from region to region. There are also the ancient, flat-lying carbonates of the interior craton that often have semi-horizontal cavities resulting from variations in ground water levels affecting bedding and the contorted rocks of the Appalachians with its apparently …

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Determination Of The Relationship Of Nitrate To Discharge And Flow Systems In North Florida Springs, Sam B. Upchurch Oct 2015

Determination Of The Relationship Of Nitrate To Discharge And Flow Systems In North Florida Springs, Sam B. Upchurch

Sinkhole Conference 2015

The Suwannee River Water Management District has collected quarterly discharge and water quality data from 30 1st and 2nd magnitude springs in the Suwannee River Basin since 1998. These data were collected quarterly well into the late 2000s and constitute a valuable database for characterizing spring discharge behavior. Trend and correlation analyses were used to compare the relationships of NO3- + NO2- (nitrate in this paper), specific conductance, and spring discharge. Trends were considered significant if alpha levels of the trend slopes were ≤ 0.05. Data from 50% of the springs show that nitrate concentrations increase as discharge from the …

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Tracking Of Karst Contamination Using Alternative Monitoring Technologies: Hidden River Cave Kentucky, Caren Raedts, Christopher Smart Oct 2015

Tracking Of Karst Contamination Using Alternative Monitoring Technologies: Hidden River Cave Kentucky, Caren Raedts, Christopher Smart

Sinkhole Conference 2015

Karst groundwater contamination presents great challenges for efficient monitoring because of rapid, discrete transport and the diversity of contaminants. Here a low cost approach is described and applied to Hidden River Cave, Kentucky, where a long history of contamination has been experienced. Local knowledge was acquired through informal interviews and coupled with observations of contaminant residues, faunal distributions and fluorescence spectra in the cave. The resulting patterns were interpreted using Google Earth and Street View to identify specific contaminant sources in the affected sub-catchment of the cave. Despite success in matching contaminant sources with the contamination history and pattern, the …

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Karst Influence In The Creation Of A Pfc Megaplume, Virginia Yingling Oct 2015

Karst Influence In The Creation Of A Pfc Megaplume, Virginia Yingling

Sinkhole Conference 2015

Perfluorochemicals (PFCs) are fully-fluorinated organic chemicals used to produce a wide range of industrial and commercial products. Their extreme persistence and mobility in the environment and nearly ubiquitous presence in humans and wildlife has raised serious concerns regarding their environmental and human health effects. In the 1940s to 1970s, PFC-bearing wastes were disposed of in three unlined landfills in Washington County, Minnesota. The resulting co-mingled PFC plumes created a “megaplume” that contaminated over 250 km2 of groundwater and four major drinking water aquifers; affecting eight municipal water supply systems and thousands of private wells. Site investigations revealed that karst features, …

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Evaluation Of Veterinary Pharmaceuticals And Iodine For Use As A Groundwater Tracer In Hydrologic Investigation Of Contamination Related To Dairy Cattle Operations, Larry Boot Pierce, Honglin Shi Oct 2015

Evaluation Of Veterinary Pharmaceuticals And Iodine For Use As A Groundwater Tracer In Hydrologic Investigation Of Contamination Related To Dairy Cattle Operations, Larry Boot Pierce, Honglin Shi

Sinkhole Conference 2015

Standard groundwater tracers such as Rhodamine WT, Fluorescein, Eosin and Tinopal CBX effectively provide a snapshot of hydrological conditions over a brief period of time and in a tightly controlled setting. However, in complex environmental situations with multiple potential sources, groundwater hydrologists are often seeking groundwater tracers that have extended longevity in the natural environment and the ability to directly pinpoint source locations. After reviewing operations of the nearby dairy it was determined that emerging contaminants, specifically two bovine veterinary pharmaceuticals (antibiotics), cephapirin sodium (CEPNa) and cephapirin benzathine (CEPB), and a sanitation agent, elemental Iodine (I) may have potential as …

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Seeps And Springs At A Platteville “Observatory” On The River Bluffs, Bj Bonin, Greg Brick, Julia R. Steenberg Oct 2015

Seeps And Springs At A Platteville “Observatory” On The River Bluffs, Bj Bonin, Greg Brick, Julia R. Steenberg

Sinkhole Conference 2015

Residential building construction along the Mississippi River bluffs in the 1970s created a unique enclosed outcrop of the Late Ordovician Platteville Formation at Lilydale, Minnesota. This outcrop was examined in early 2013 after a newly-formed spring flooded an elevator shaft the previous year, drawing attention to the foundation conditions. The Lexington Riverside property is a six story condominium complex constructed within the top of the bluff. A two-level underground parking garage was built into the bluff. Bedrock was mechanically excavated to accommodate the construction of the building, creating an unweathered rock surface. The space between the structure and the excavated …

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Karst Spring Cutoffs, Cave Tiers, And Sinking Stream Basins Correlated To Fluvial Base Level Decline In South-Central Indiana, Garre A. Conner Oct 2015

Karst Spring Cutoffs, Cave Tiers, And Sinking Stream Basins Correlated To Fluvial Base Level Decline In South-Central Indiana, Garre A. Conner

Sinkhole Conference 2015

The Mitchell Aquifer averages 80m in thickness and underdrains a karst region in the Crawford Upland and Mitchell Plateau region in south-central Indiana (110,000 km2). The Springville Escarpment is a transitional boundary between the upland and plateau. Cave stream linking between cave tiers in the aquifer and correlation of cave tier inception horizons to a base level decline surface is interpreted for the Kirby Watershed, encompassing the prekarst headland of Indian Creek (42km2). The watershed was severed from lower Indian Creek at Eller Col by limestone cavern drainage on the ridge between White River and East Fork. Correlation of recharge …

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Using Nitrate, Chloride, Sodium, And Sulfate To Calculate Groundwater Age, Kimm Crawford, Terry Lee Oct 2015

Using Nitrate, Chloride, Sodium, And Sulfate To Calculate Groundwater Age, Kimm Crawford, Terry Lee

Sinkhole Conference 2015

Regression analysis is used to identify monotonic trends to assign water age using ion data from two large well water databases from southeast Minnesota (SE MN). Nitrate (NO3-N), chloride (Cl), sodium (Na), and sulfate (SO4) ions in the commonly used aquifers in SE MN can be used as groundwater tracers since they are either entirely or partly anthropogenic in their sources, their loading occurs on a regional scale, and they are almost entirely conserved. Ion concentrations over time are used to establish six trend patterns. Two patterns are unchanging (background and stable above background), and four are changing (linear up, …

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Conduit Flow In The Cambrian Lone Rock Formation, Southeast Minnesota, U.S.A., John D. Barry, Jeffrey A. Green, Julia R. Steenberg Oct 2015

Conduit Flow In The Cambrian Lone Rock Formation, Southeast Minnesota, U.S.A., John D. Barry, Jeffrey A. Green, Julia R. Steenberg

Sinkhole Conference 2015

The karst lands of southeast Minnesota contain more than one hundred trout streams that receive perennial discharge from Paleozoic bedrock springs. Several of the Paleozoic bedrock units that provide discharge are karst aquifers. Field investigations into the flow characteristics of these formations have been conducted using fluorescent dyes to map groundwater springsheds and characterize groundwater flow velocities for use in water resource protection. Recent field work has focused on the Cambrian Lone Rock Formation, a siliciclastic unit consisting of very fine-grained sandstone and siltstone with minor beds of shale and dolostone. The formation is mapped within tributary valleys of the …

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Hydrologic And Geochemical Dynamics Of Vadose Zone Recharge In A Mantled Karst Aquifer: Results Of Monitoring Drip Waters In Mystery Cave, Minnesota, Daniel H. Doctor, E. Calvin Alexander Jr., Roy Jameson, Scott C. Alexander Oct 2015

Hydrologic And Geochemical Dynamics Of Vadose Zone Recharge In A Mantled Karst Aquifer: Results Of Monitoring Drip Waters In Mystery Cave, Minnesota, Daniel H. Doctor, E. Calvin Alexander Jr., Roy Jameson, Scott C. Alexander

Sinkhole Conference 2015

Caves provide direct access to flows through the vadose zone that recharge karst aquifers. Although many recent studies have documented the highly dynamic processes associated with vadose zone flows in karst settings, few have been conducted in mantled karst settings, such as that of southeastern Minnesota. Here we present some results of a long-term program of cave drip monitoring conducted within Mystery Cave, Minnesota. In this study, two perennial ceiling drip sites were monitored between 1997 and 2001. The sites were located about 90 m (300 ft) apart along the same cave passage approximately 18 m (60 ft) below the …

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Human Impacts On Water Quality In Coldwater Spring, Minneapolis, Minnesota, Sophie M. Kasahara, E. Calvin Alexander Jr., Scott C. Alexander Oct 2015

Human Impacts On Water Quality In Coldwater Spring, Minneapolis, Minnesota, Sophie M. Kasahara, E. Calvin Alexander Jr., Scott C. Alexander

Sinkhole Conference 2015

Coldwater Spring in Minneapolis, Minnesota was the water supply for Fort Snelling from the 1840s to 1920. The spring site has been declared a sacred site by some federally recognized Native American tribes. The site is managed by the National Park Service. This project has monitored the water chemistry of Coldwater Spring to document human impacts on the spring’s water quality. Temperature, dissolved oxygen, conductivity, pH and anions were monitored weekly and cations and alkalinity monitored monthly at Coldwater Spring and the adjacent Wetland A from 15 February 2013 through 18 January 2015. Coldwater Spring’s water flows through fractures in …

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Karst Hydrogeologic Investigation Of Trout Brook, Joel T. Groten, E. Calvin Alexander Jr. Oct 2015

Karst Hydrogeologic Investigation Of Trout Brook, Joel T. Groten, E. Calvin Alexander Jr.

Sinkhole Conference 2015

Trout Brook in the Miesville Ravine County Park of Dakota County Minnesota is the trout stream with the highest nitrate concentration in the karst region of southeastern Minnesota. Water quality data from 1985 and 1995 (Spong, 1995) and from 2001, 2002, 2006, 2010, and 2014, collected by the Dakota County Soil and Water Conservation District (Dakota SWCD, 2014) document an increasing level of nitrate in Trout Brook. A karst hydrogeologic investigation was designed to measure nitrate levels at sampling points along the stream and to increase our understanding of the source and movement of nitrates throughout the length of Trout …

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Tracer Studies Conducted Nearly Two Decades Apart Elucidate Groundwater Movement Through A Karst Aquifer In The Frederick Valley Of Maryland, Keith A. White, Michael K. Cobb, Thomas Aley, Ethan Weikel Oct 2015

Tracer Studies Conducted Nearly Two Decades Apart Elucidate Groundwater Movement Through A Karst Aquifer In The Frederick Valley Of Maryland, Keith A. White, Michael K. Cobb, Thomas Aley, Ethan Weikel

Sinkhole Conference 2015

A pair of groundwater tracer studies at a single karst test site were completed 18 years apart. The results of these studies have provided evidence of both relatively rapid advective transport via conduits and an extreme capacity for dye storage and retardation. The tracer results, coupled with other subsurface investigation data, are used to develop a conceptual model for groundwater movement through this karst aquifer in the Frederick Valley of Maryland, as well as identify implications for remediation. Three fluorescent tracer dyes used in the initial study were detected in several background monitoring locations established for the second study conducted …

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Hydrological And Hydrogeological Characteristics Of The Platform Karst (Zemo Imereti Plateau, Georgia), Zaza Lezhava, Nana Bolashvili, Kukuri Tsikarishvili, Lasha Asanidze, Nino Chikhradze Oct 2015

Hydrological And Hydrogeological Characteristics Of The Platform Karst (Zemo Imereti Plateau, Georgia), Zaza Lezhava, Nana Bolashvili, Kukuri Tsikarishvili, Lasha Asanidze, Nino Chikhradze

Sinkhole Conference 2015

The article discusses the hydrological and hydrogeological characteristics of the platform karst of Zemo Imereti plateau. The structural plateau of Zemo Imereti is the part of the intermountain plain karst zone of Georgia and one of the interesting parts of the karst relief development. The above mentioned karst region includes the easternmost part of western Georgia, which is characterized by peculiar natural conditions (relief, tectonics, climate, surface and underground streams) and represents one of the significant platform karst regions in the Caucasus. On the basis of the cartographic materials (GIS) analysis and borehole data the general scheme of hydrogeological setting …

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Recharge Area Of Selected Large Springs In The Ozarks, Bill Duley, Cecil Boswell, Jerry Prewett Oct 2015

Recharge Area Of Selected Large Springs In The Ozarks, Bill Duley, Cecil Boswell, Jerry Prewett

Sinkhole Conference 2015

Ongoing work by the Missouri Geological Survey (MGS) is refining the known recharge areas of a number of major springs in the Ozarks. Among the springs being investigated are: Mammoth Spring (Fulton County, Arkansas), and the following Missouri springs: Greer Spring (Oregon County), Blue Spring (Ozark County), Blue/Morgan Spring Complex (Oregon County), Boze Mill Spring (Oregon County), two different Big Springs (Carter and Douglas County) and Rainbow/North Fork/Hodgson Mill Spring Complex (Ozark County). Previously unpublished findings of the MGS and United States Geological Survey (USGS) are also being used to better define recharge areas of Greer Spring, Big Spring (Carter …

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Hydrogeological Dynamic Variability In The Lomme Karst System (Belgium) As Evidenced By Tracer Tests Results (Karag Project), Amaël Poulain, Gaëtan Rochez, Vincent Hallet Oct 2015

Hydrogeological Dynamic Variability In The Lomme Karst System (Belgium) As Evidenced By Tracer Tests Results (Karag Project), Amaël Poulain, Gaëtan Rochez, Vincent Hallet

Sinkhole Conference 2015

Paleozoic carbonate aquifers represent major groundwater resources in Belgium. Karstification processes affect most of them and Belgium counts many hydrologically active karst networks. Given the intrinsic vulnerability of such geological objects, comprehensive studies are required in order to improve their protection and management. The KARAG project (Karst Aquifer ReseArch by Geophysic, 2013-2017) aims to identify the specific dynamic of karst aquifers by using geophysical and hydrogeological tools. This research is funded by the Belgium National Fund for Scientific Research (FNRS) and conducted by the University of Namur, University of Mons and the Royal Observatory of Belgium. The LKS – Lomme …

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An Omnibus Nonparametric Test Of Equality In Distribution For Unknown Functions, Alexander Luedtke, Marco Carone, Mark Van Der Laan Oct 2015

An Omnibus Nonparametric Test Of Equality In Distribution For Unknown Functions, Alexander Luedtke, Marco Carone, Mark Van Der Laan

Alex Luedtke

We present a novel family of nonparametric omnibus tests of the hypothesis that two unknown but estimable functions are equal in distribution when applied to the observed data structure. We developed these tests, which represent a generalization of the maximum mean discrepancy tests described in Gretton et al. [2006], using recent developments from the higher-order pathwise differentiability literature. Despite their complex derivation, the associated test statistics can be expressed rather simply as U-statistics. We study the asymptotic behavior of the proposed tests under the null hypothesis and under both fixed and local alternatives. We provide examples to which our tests …

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Adding Light To The Gravitational Waves On The Null Cone, Maria Babiuc-Hamilton Oct 2015

Adding Light To The Gravitational Waves On The Null Cone, Maria Babiuc-Hamilton

Maria C. Babiuc-Hamilton

Recent interesting astrophysical observations point towards a multi-messenger, multi-wavelength approach to understanding strong gravitational sources, like compact stars or black hole collisions, supernovae explosions, or even the big bang. Gravitational radiation is properly defined only at future null infinity, but usually is estimated at a finite radius, and then extrapolated. Our group developed a characteristic waveform extraction tool, implemented in an open source code, which computes the gravitational waves infinitely far from their source, in terms of compactified null cones, by numerically solving Einstein equation in Bondi space-time coordinates. The goal is extend the capabilities of the code, by solving …

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Steps Towards The Well-Posedness Of The Characteristic Evolution For The Einstein Equations, Maria Babiuc-Hamilton Oct 2015

Steps Towards The Well-Posedness Of The Characteristic Evolution For The Einstein Equations, Maria Babiuc-Hamilton

Maria C. Babiuc-Hamilton

The correct modeling of gravitational radiation is a key requirement for a meaningful detection and interpretation of data. The Cauchy-characteristic technique connects the strong-field Cauchy evolution of the space-time near the black-hole merger to the characteristic evolution at future null infinity, where the waveform is properly defined. The PITT Null code, publicly available, is the most precise and refined computational method for the extraction of gravitational waves, but is not well-posed. The numerical relativity community recognizes that a well-posed problem is the only way to ensure that a code is stable and dependable. The well-posedness of the null-timelike problem for …

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Using Water–Solvent Systems To Estimate In Vivo Blood–Tissue Partition Coefficients, Andrew Lang, Caitlin E. Derricott Oct 2015

Using Water–Solvent Systems To Estimate In Vivo Blood–Tissue Partition Coefficients, Andrew Lang, Caitlin E. Derricott

College of Science and Engineering Faculty Research and Scholarship

Background: Blood–tissue partition coefficients indicate how a chemical will distribute throughout the body and are an important part of any pharmacokinetic study. They can be used to assess potential toxicological effects from exposure to chemicals and the efficacy of potential novel drugs designed to target certain organs or the central nervous system. In vivo measurement of blood–tissue partition coefficients is often complicated, time-consuming, and relatively expensive, so developing in vitro systems that approximate in vivo ones is desirable. We have determined such systems for tissues such as brain, muscle, liver, lung, kidney, heart, skin, and fat. Results: Several good (p < 0.05) blood–tissue partition coefficient models were developed using a single water– solvent system. These include blood–brain, blood–lung, blood–heart, blood–fat, blood–skin, water–skin, and skin permeation. Many of these partition coefficients have multiple water–solvent systems that can be used as models. Several solvents—methylcyclohexane, 1,9-decadiene, and 2,2,2-trifluoroethanol—were common to multiple models and thus a single measurement can be used to estimate multiple blood–tissue partition coefficients. A few blood–tissue systems require a combination of two water–solvent partition coefficient measurements to model well (p < 0.01), namely: blood–muscle: chloroform and dibutyl ether, blood–liver: N-methyl-2-piperidone and ethanol/water (60:40) volume, and blood–kidney: DMSO and ethanol/water (20:80) volume. Conclusion: In vivo blood–tissue partition coefficients can be easily estimated through water–solvent partition coefficient measurements.

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Supporting Teachers’ Learning About Mathematical Modeling, June L. Gastón, Barbara A. Lawrence Oct 2015

Supporting Teachers’ Learning About Mathematical Modeling, June L. Gastón, Barbara A. Lawrence

Publications and Research

In the United States, one of the Standards for Mathematical Practice of the Common Core Curriculum (Common Core State Standards Initiative, 2010) is Model with mathematics. This standard requires that students be taught in a manner that will enable them to ―apply the mathematics they know to solve problems arising in everyday life, society, and the workplace‖ (p. 7). However many prospective and practicing teachers acquire a pedagogical style that does not support this standard. To promote higher levels of student thinking associated with mathematical modeling, teachers must thus be taught not only what mathematical modeling is, but how it …

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Cellular Hokey Pokey: A Coarse-Grained Model Of Lamellipodia Protrusion Dynamics Driven By Fluctuations In Actin Polymerization, Gillian Ryan, Dimitrios Vavylonis, Naoki Watanabe Oct 2015

Cellular Hokey Pokey: A Coarse-Grained Model Of Lamellipodia Protrusion Dynamics Driven By Fluctuations In Actin Polymerization, Gillian Ryan, Dimitrios Vavylonis, Naoki Watanabe

Physics Publications

Animal cells that spread onto a surface often rely on actin-rich cell extensions called lamellipodia to execute cell protrusion. XTC cells on a two-dimensional substrate exhibit regular protrusion and retraction of their lamellipodium, even though the cell is not translating. Travelling waves of protrusion have also been observed, similar to those observed in crawling cells. These periodic fluctuations in leading edge position have been linked to excitable actin dynamics near the cell edge using a one dimensional model of actin dynamics, as a function of arc-length along the cell. In this work we extend this earlier model of actin dynamics …

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Integration And Delivery Of Interferometric Synthetic Aperture Radar [Insar] Data Into Stormwater Planning Within Karst Terranes, Brian Bruckno, Andrea Vaccari, Edward Hoppe, Scott Acton, Elizabeth Campbell Oct 2015

Integration And Delivery Of Interferometric Synthetic Aperture Radar [Insar] Data Into Stormwater Planning Within Karst Terranes, Brian Bruckno, Andrea Vaccari, Edward Hoppe, Scott Acton, Elizabeth Campbell

Department of Earth and Atmospheric Sciences: Faculty Publications

As part of two USDOT-funded studies focused on the development of satellite-based Interferometric Synthetic Aperture Radar (InSAR) technology, the researchers integrated InSAR-derived point cloud data into the transportation design process to optimize the location of a stormwater management system in a karst terrane. After initial validation, the InSAR data (over 1.67 million data points comprising various “scatterers”) were brought into a GIS dataframe and georeferenced to locations of known sinkholes. This dataset was then used to evaluate karst hazard within a 40x40km data frame located in the Valley and Ridge Province of Virginia. The group identified systematic kinematic differences in …

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Crystallization Engineering As A Route To Epitaxial Strain Control, Andrew R. Akbashev, Aleksandr V. Plokhikh, Dmitri Barbash, Samuel Lofland, Jonathan E. Spanier Oct 2015

Crystallization Engineering As A Route To Epitaxial Strain Control, Andrew R. Akbashev, Aleksandr V. Plokhikh, Dmitri Barbash, Samuel Lofland, Jonathan E. Spanier

College of Science & Mathematics Departmental Research

The controlled synthesis of epitaxial thin films offers opportunities for tuning their functional properties via enabling or suppressing strain relaxation. Examining differences in the epitaxial crystallization of amorphous oxide films, we report on an alternate, low-temperature route for strain engineering. Thin films of amorphous Bi–Fe–O were grown on (001)SrTiO3 and (001)LaAlO3substrates via atomic layer deposition. In situ X-ray diffraction and X-ray photoelectron spectroscopy studies of the crystallization of the amorphous films into the epitaxial (001)BiFeO3 phase reveal distinct evolution profiles of crystallinity with temperature. While growth on (001)SrTiO3 results in a coherently strained film, the same films obtained on (001)LaAlO3 …

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A Coordinated Study Of 1 H Mesoscale Gravity Waves Propagating From Logan To Boulder With Crrl Na Doppler Lidars And Temperature Mapper, Xian Lu, Cao Chen, Wentao Huang, John A. Smith, Xinzhao Chu, Tao Yuan, Pierre-Dominique Pautet, Michael J. Taylor, Jie Gong, Chihoko Y. Cullens Oct 2015

A Coordinated Study Of 1 H Mesoscale Gravity Waves Propagating From Logan To Boulder With Crrl Na Doppler Lidars And Temperature Mapper, Xian Lu, Cao Chen, Wentao Huang, John A. Smith, Xinzhao Chu, Tao Yuan, Pierre-Dominique Pautet, Michael J. Taylor, Jie Gong, Chihoko Y. Cullens

All Physics Faculty Publications

We present the first coordinated study using two lidars at two separate locations to characterize a 1 h mesoscale gravity wave event in the mesopause region. The simultaneous observations were made with the Student Training and Atmospheric Research (STAR) Na Doppler lidar at Boulder, CO, and the Utah State University Na Doppler lidar and temperature mapper at Logan, UT, on 27 November 2013. The high precision possessed by the STAR lidar enabled these waves to be detected in vertical wind. The mean wave amplitudes are ~0.44 m/s in vertical wind and ~1% in relative temperature at altitudes of 82–107 km. …

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Observations Of Backscatter From Sand And Gravel Seafloors Between 170-250 Khz, Thomas C. Weber, Larry G. Ward Oct 2015

Observations Of Backscatter From Sand And Gravel Seafloors Between 170-250 Khz, Thomas C. Weber, Larry G. Ward

Center for Coastal and Ocean Mapping

Interpreting observations of frequency-dependence in backscatter from the seafloor offers many challenges, either because multiple frequencies are used for different observations that will later be merged or simply because seafloor scattering models are not well-understood above 100 kHz. Hindering the understanding of these observations is the paucity of reported, calibratedacoustic measurements above 100 kHz. This manuscript seeks to help elucidate the linkages between seafloor properties and frequency-dependent seafloor backscatter by describing observations of backscatter collected from sand, gravel, and bedrock seafloors at frequencies between 170 and 250 kHz and at a grazing angle of 45°. Overall, the frequency dependence appeared …

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Overlap Statistics Of Shallow Boundary Layer Clouds: Comparing Ground-Based Observations With Large-Eddy Simulations, G. Corbetta, E. Orlandi, Thijs Heus, Roel Neggers, S. Crewell Oct 2015

Overlap Statistics Of Shallow Boundary Layer Clouds: Comparing Ground-Based Observations With Large-Eddy Simulations, G. Corbetta, E. Orlandi, Thijs Heus, Roel Neggers, S. Crewell

Physics Faculty Publications

High-resolution ground-based measurements are used to assess the realism of fine-scale numerical simulations of shallow cumulus cloud fields. The overlap statistics of cumuli as produced by large-eddy simulations (LES) are confronted with Cloudnet data sets at the Jülich Observatory for Cloud Evolution. The Cloudnet pixel is small enough to detect cumuliform cloud overlap. Cloud fraction masks are derived for five different cases, using gridded time-height data sets at various temporal and vertical resolutions. The overlap ratio (R), i.e., the ratio between cloud fraction by volume and by area, is studied as a function of the vertical resolution. Good agreement is …

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