Physical Sciences and Mathematics Commons^™

Range Of Horizontal Transport And Residence Time Of Nitrate In A Mature Karst Vadose Zone, Jiri Kamas, Jiri Bruthans, Helena Vysoka, Miroslav Kovařík

International Journal of Speleology

Nitrate concentrations in drips in Amaterska, Spolecnak, and Holstejnska caves situated below a 25 to 120 m thick vadose zone in the Moravian Karst, Central Europe were studied during several periods from 1992. Each cave runs below a land-use boundary between fertilized lands and forest, which enabled study of the range of horizontal components of nitrate transport in the vadose zone. Parts of the fertilized land were turned into grassland in 1998 and 2003, and the cave drips were sampled both prior and after the changes in land use. The mean residence time of nitrate is - 30 m thick …

Hairy Stalagmites, A New Biogenic Root Speleothem From Botswana, Gerhard C. Du Preez, Paolo Forti, Gerhard Jacobs, Anine Jordaan, Louwrens Tiedt

International Journal of Speleology

Ngamiland in northwestern Botswana hosts the Gcwihaba Caves which present unique subterranean environments and host speleothems never before recorded. Cave atmospheric conditions can be extreme with temperatures as high as 28°C and relative humidity nearing 99.9%. Within Dimapo and Diviner’s Caves peculiar root speleothems that we named ‘Hairy Stalagmites’ were found. These stalagmites are closely associated with the roots of Namaqua fig (Ficus cordata) trees that enter the cave environment in search of water. Pieces of broken stalagmites were sampled from Dimapo Cave for further investigations. Stereo and electron microscopy revealed that the Hairy Stalagmites consist of multiple …

High-Resolution Digital 3d Models Of Algar Do Penico Chamber: Limitations, Challenges, And Potential, Ivo Silvestre M.Sc., José I. Rodrigues Phd, Mauro Figueiredo Phd, Cristina Veiga-Pires Phd

International Journal of Speleology

The study of karst and its geomorphological structures is important for understanding the relationships between hydrology and climate over geological time. In that context, we conducted a terrestrial laser-scan survey to map geomorphological structures in the karst cave of Algar do Penico in southern Portugal. The point cloud data set obtained was used to generate 3D meshes with different levels of detail, allowing the limitations of mapping capabilities to be explored.

In addition to cave mapping, the study focuses on 3D-mesh analysis, including the development of two algorithms for determination of stalactite extremities and contour lines, and on the interactive …

U.S. Drought Monitor, November 25, 2014, Eric Luebehusen

United States Agricultural Commodities in Drought Archive

Drought map of U.S. for November 25, 2014 (11/25/14) plus: U.S. crop areas experiencing drought (map), Approximate percentage of crop located in drought, by state (bar graph), Percent of crop area located in drought, past 52 weeks (line graph) for: Corn, Soybeans, Hay, Cattle, Winter wheat.

Catechol Oxidation By Ozone And Hydroxyl Radicals At The Air-Water Interface, Elizabeth A. Pillar, Robert C. Camm, Marcelo I. Guzman

Chemistry Faculty Publications

Anthropogenic emissions of aromatic hydrocarbons promptly react with hydroxyl radicals undergoing oxidation to form phenols and polyphenols (e.g., catechol) typically identified in the complex mixture of humic-like substances (HULIS). Because further processing of polyphenols in secondary organic aerosols (SOA) can continue mediated by a mechanism of ozonolysis at interfaces, a better understanding about how these reactions proceed at the air–water interface is needed. This work shows how catechol, a molecular probe of the oxygenated aromatic hydrocarbons present in SOA, can contribute interfacial reactive species that enhance the production of HULIS under atmospheric conditions. Reactive semiquinone radicals are quickly produced upon …

Neural Network Dynamic Progamming Constrained Control Of Distributed Parameter Systems Governed By Parabolic Partial Differential Equations With Application To Diffusion-Reaction Processes, Behzad Talaei, Hao Xu, S. Jagannathan

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, a novel neural network (NN) adaptive dynamic programming (ADP) control scheme for distributed parameter systems (DPS) governed by parabolic partial differential equations (PDE) is introduced in the presence of control constraints and unknown system dynamics. First, Galerkin method is utilized to develop a relevant reduced order system which captures the dominant dynamics of the DPS. Subsequently, a novel control scheme is proposed over finite horizon by using NN ADP. To relax the requirement of system dynamics, a novel NN identifier is developed. More-over, a second NN is proposed to estimate online the time-varying non-quadratic value function from …

Empirical Formulas For Direct Double Ionization By Bare Ions: Z=-1 To 92, Robert D. Dubois, A. C.F. Santos, S. T. Manson

Physics Faculty Research & Creative Works

Experimental cross sections and cross-section ratios reported in the literature for direct double ionization of the outer shells of helium, neon, and argon atoms resulting from bare ions ranging from protons to uranium and for antiprotons are analyzed in terms of a first- and second-order interference model originally proposed by McGuire [J. H. McGuire, Phys. Rev. Lett. 49, 1153 (1982) PRLTAO0031-900710.1103/PhysRevLett.49.1153]. Empirical formulas for the various contributions to double ionization plus information about the phase difference between the first- and second-order mechanisms are extracted from the data. Projectile and target scaling's are also extracted. Total cross sections and their ratios …

The First Month Of Evolution Of The Slow-Rising Type Iip Sn 2013ej In M74, S. Valenti, D. Sand, A. Pastorello, M. L. Graham, D. A. Howell, J. T. Parrent

Dartmouth Scholarship

We present early photometric and spectroscopic observations of SN 2013ej, a bright Type IIP supernova (SN) in M74. SN 2013ej is one of the closest SNe ever discovered. The available archive images and the early discovery help to constrain the nature of its progenitor. The earliest detection of this explosion was on 2013 July 24.125 ut and our spectroscopic monitoring with the FLOYDS spectrographs began on July 27.7 ut, continuing almost daily for two weeks. Daily optical photometric monitoring was achieved with the 1 m telescopes of the Las Cumbres Observatory Global Telescope (LCOGT) network, and was complemented by UV …

Upward Flow Constructed Wetland For Treatment Of Water Contaminated With Chlorinated Aliphatics, Michael Shelley, Abinash Agrawal, Ke Qin, Garrett Struckhoff, Carl Enfield, James Waldron, Christina Powell

AFIT Patents

An improved upward flow constructed wetland cell for treatment of water contaminated with chlorinated aliphatics is disclosed. The improvements include adding ammonia-oxidizing microorganisms to the methane-oxidizing microorganisms already present in an oxygenated root zone and adding improved pore-water sample chambers for measuring the performance of the constructed wetland cell.

Quantifying An Adherence Path-Specific Effect Of Antiretroviral Therapy In The Nigeria Pepfar Program, Caleb Miles, Ilya Shpitser, Phyllis Kanki, Seema Meloni, Eric J. Tchetgen Tchetgen

Harvard University Biostatistics Working Paper Series

No abstract provided.

On The Restricted Mean Survival Time Curve Survival Analysis, Lihui Zhao, Brian Claggett, Lu Tian, Hajime Uno, Marc A. Pfeffer, Scott D. Solomon, Lorenzo Trippa, L. J. Wei

Harvard University Biostatistics Working Paper Series

No abstract provided.

Ferroelectric Tunnel Junctions With Graphene Electrodes, Haidong Lu, Alexey Lipatov, Sangjin Ryu, D. J. Kim, H. Lee, M. Ye. Zhuravlev, Chang-Beom Eom, Evgeny Y. Tsymbal, Alexander Sinitskii, Alexei Gruverman

Evgeny Tsymbal Publications

Polarization-driven resistive switching in ferroelectric tunnel junctions (FTJs)—structures composed of two electrodes separated by an ultrathin ferroelectric barrier—offers new physics and materials functionalities, as well as exciting opportunities for the next generation of non-volatile memories and logic devices. Performance of FTJs is highly sensitive to the electrical boundary conditions, which can be controlled by electrode material and/or interface engineering. Here, we demonstrate the use of graphene as electrodes in FTJs that allows control of interface properties for significant enhancement of device performance. Ferroelectric polarization stability and resistive switching are strongly affected by a molecular layer at the graphene/BaTiO₃ interface. …

A Review Of Software For Analyzing Molecular Sequences, Haema Nilakanta, Kimberly L. Drews, Suzanne Firrell, Mary A. Foulkes, Kathleen A. Jablonski

GW Biostatistics Center

Background Over the past ten years, there has been an explosion of microbiome research. Many software packages for analyzing microbial sequences such as the 16S gene from 454 sequencers and Illumina platforms are available. But for a new researcher, it is difficult to know which package to choose. We present a systematic review of packages for the analysis of molecular sequences used to describe and compare microbial communities. This review gives students and researchers information to help choose the best analytic pipeline for their project. To the best of our knowledge, this is the first review of such software.

Findings …

The Detection Of Peroxynitrite Using 19f Magnetic Resonance Probes, Kevin Bruemmer

Collection of Engaged Learning

The following report presents the work done by Kevin Bruemmer for his Engaged Learning project. The 19F magnetic resonance probes 5-uoroisatin and 6-uoroisatin were reacted with ONOO- to yield anthranilic acid derivatives through a novel oxidative decarbonyaltion reaction. Utilizing 19F NMR spectroscopy techniques, the presence of ONOO- can be determined through a chemical shift switching signal. 5-uoroisatin was subsequently used to detect ONOO- in living lung epithelial cells.

Synthesis Of Hydrogenated Thiol-Silanes For Selective Reactions, Macartney Welborn

Collection of Engaged Learning

The intention of this experiment is to show the creation of multifunctional thiols from the reaction between various hydrochlorosilanes and mercaptoethanol in an attempt to utilize their distinct properties for practical applications. Multifunctional thiols have many useful applications including use in high-refractive-index lenses, ¹ heavy metal chelation, ² and degradable plastics³. Previous work, ⁵ in our lab has explored a class of reactions key to the synthesis of these compounds: the reaction between methylated chlorosilanes with mercaptoalcohols. We extended this reaction to include hydrogenated chlorosilanes. This allows us to produce multifunctional thiols with an additional functionalizable position at …

The Number Of Framings Of A Knot In A 3-Manifold, Patricia Cahn, Vladimir Chernov, Rustam Sadykov

Mathematics Sciences: Faculty Publications

In view of the self-linking invariant, the number |K| of framed knots in S3 with given underlying knot K is infinite. In fact, the second author previously defined affine self-linking invariants and used them to show that |K| is infinite for every knot in an orientable manifold unless the manifold contains a connected sum factor of S1 × S2; the knot K need not be zero-homologous and the manifold is not required to be compact. We show that when M is orientable, the number |K| is infinite unless K intersects a nonseparating sphere at exactly one point, in which case …

Fearless Friday: Sean Pethybridge, Christina L. Bassler

SURGE

Talking with Sean Pethybridge ’15, one could easily assume his interest in agriculture and food justice developed at a very young age. Sean confesses that he had very limited knowledge prior to attending Gettysburg. “My grandpa had a garden and the most experience I had with that was picking green beans during the summer time when I was younger,” he jokes. [excerpt]

Comment On “Chemically Mediated Behavior Of Recruiting Corals And Fishes: A Tipping Point That May Limit Reef Recovery”, Andrew H. Baird, Vivian R. Cumbo, Joana Figueiredo, Saki Harii, Tom Hata, Joshua S. Madin

Marine & Environmental Sciences Faculty Articles

Dixson et al. (2014) report that coral larvae navigate towards chemical cues associated with healthy reefs and avoid cues from degraded reefs. However, the swimming capabilities of coral larvae and well-established patterns of recruitment and reef hydrodynamics indicate that coral larvae will not be able to use these cues to recruit to healthy reefs. Perfuming degraded reefs, as suggested by Dixson et al (2014), will not enhance recovery rather it will distract from the difficult task of reducing fishing effort and improving water quality.

Preliminary Analysis Of Thermal Reactions Of Select Metals With Chalcogens, Elizabeth G. Cook

Student Theses and Dissertations

Metal sulfides and selenides are important industrially as semiconductor materials, pigments, electrochemical cells, solar energy conversion and catalysts. The purpose of this study was to determine if a reaction occurs at elevated temperatures between sulfur and selenium with electropositive metals. Reactions were studied using a TG/DTA instrument. The metals used to react with sulfur were copper, nickel, lead, cobalt, manganese, iron, zinc, and cadmium. For comparison, copper, lead, and nickel were reacted with elemental selenium.

Line-Driven Radiative Outflows In Luminous Quasars, Rebecca A. A. Bowler, Paul C. Hewett, James T. Allen, Gary J. Ferland

Physics and Astronomy Faculty Publications

An analysis of ≃19 500 narrow ( ≲ 200 km s⁻¹) C iv λλ1548.2,1550.8 absorbers in ≃34 000 Sloan Digital Sky Survey quasar spectra is presented. The statistics of the number of absorbers as a function of outflow velocity shows that in approximately two-thirds of outflows, with multiple C iv absorbers present, absorbers are line-locked at the 500 km s⁻¹ velocity separation of the C iv absorber doublet; appearing as ‘triplets’ in the quasar spectra. Line-locking is an observational signature of radiative line-driving in outflowing material, where the successive shielding of ‘clouds’ of material in the outflow …

Mr-Tree: A Customizable Gpu Mapreduce Framework, Zhi Qiao

Student Theses and Dissertations

The MapReduce programming model has been criticized for a long time for its lack of flexibility to apply on many difficult scientific computations. Currently, several approaches try to conduct a more flexible MapReduce framework, but some of them are required to run on a particular platform, others have a lack of support to GPU environments. In this thesis, we present MR-Tree, a customizable GPU MapReduce framework. In MR-Tree, users can configure each task's data I/O behavior, so computations that have strong data dependency will no longer hold back the MapReduce runtime. Moreover, MR-Tree also features configurable workflow. Users can arrange …

Chemistry Graduate Teaching Assistants' Experiences In Academic Laboratories And Development Of A Teaching Self-Image, Todd Adam Gatlin

USF Tampa Graduate Theses and Dissertations

Graduate teaching assistants (GTAs) play a prominent role in chemistry laboratory instruction at research based universities. They teach almost all undergraduate chemistry laboratory courses. However, their role in laboratory instruction has often been overlooked in educational research. Interest in chemistry GTAs has been placed on training and their perceived expectations, but less attention has been paid to their experiences or their potential benefits from teaching.

This work was designed to investigate GTAs' experiences in and benefits from laboratory instructional environments. This dissertation includes three related studies on GTAs' experiences teaching in general chemistry laboratories. Qualitative methods were used for each …

Effects Of Ocean Acidification On The Dissolution Rates Of Reef-Coral Skeletons, Robert Van Woesik, Kelly Van Woesik, Liana Van Woesik, Sandra Van Woesik

Ocean Engineering and Marine Sciences Faculty Publications

Ocean acidification threatens the foundation of tropical coral reefs. This study investigated three aspects of ocean acidification: (i) the rates at which perforate and imperforate coral-colony skeletons passively dissolve when pH is 7.8, which is predicted to occur globally by 2100, (ii) the rates of passive dissolution of corals with respect to coral-colony surface areas, and (iii) the comparative rates of a vertical reef-growth model, incorporating passive dissolution rates, and predicted sea-level rise. By 2100, when the ocean pH is expected to be 7.8, perforate Montipora coral skeletons will lose on average 15 kg CaCO3 m􀀀2 y􀀀1, which is approximately …

Confined Mesoscopic Fluid-Like Films Analyzed With Frequency Modulation And Acoustic Detection, Rodolfo Fernandez Rodriguez

Dissertations and Theses

Complete understanding of the physics underlying the changes in viscoelasticity, relaxation time, and phase transitions that mesoscopic fluid-like systems undergo at solid-liquid interfaces or under confinement remains one of the major challenges in condensed matter physics. Moreover, studies of confined mesoscopic fluid films are relevant to technological areas like adhesion, wetting processes and nanotribology.

This thesis addresses the interaction between two sliding solids interfaces separated by a nanometer sized gap, with emphasis on the role of the mesoscopic fluid film trapped between them. For this purpose we integrated two acoustic techniques, recently introduced by our group, into a sub-nanometer precision …

Can Xrf Scanning Of Speleothems Be Used As A Non-Destructive Method To Identify Paleoflood Events In Caves?, Martin Finné, Malin Kylander, Meighan Boyd, Hanna S. Sundqvist, Ludvig Löwemark

International Journal of Speleology

We have developed a novel, quick and non-destructive method for tracing flood events in caves through the analysis of a stalagmite thick section with an XRF core scanner. The analyzed stalagmite has multiple horizons of fine sediments from past flood events intercalated with areas of cleaner calcite. Flood events detected from the elemental XRF core scanning data show good agreement with the position of flood horizons identified in petrographic thin sections. The geochemical composition of the individual flood layers shows that in certain cases the clay horizons had a distinct geochemical fingerprint suggesting that it may be possible to distinguish …

Microstratigraphic Logging Of Calcite Fabrics In Speleothems As Tool For Palaeoclimate Studies, Silvia Frisia

International Journal of Speleology

The systematic documentation of calcite fabrics in stalagmites and flowstones provides robustness to palaeoclimate interpretation based on geochemical proxies, but it has been neglected because it is difficult to transform crystal morphologies into numerical values, and construct fabric time series. Here, general criteria that allow for coding fabrics of calcite composing stalagmites and flowstones is provided. Being based on known models of fabric development, the coding ascribes sequential numbers to each fabric, which reflect climate-related parameters, such as changes in drip rate variability, bio-mediation or diagenetic modifications. Acronyms are proposed for Columnar types, Dendritic, Micrite, Microsparite and Mosaic fabrics, whose …

Leadership - A Lifetime Quest For Excellence, Douglas D. Piirto

Natural Resources Management and Environmental Sciences

This paper is written for aspiring leaders and managers. Each of us will be asked to lead, manage, and/or follow at various times and in many different situations in our journey of life. This paper is written to assist aspiring leaders and managers discover and develop their leadership and management abilities.

The paper is organized per the following outline:

• Introduction
• Establishing Credibility
• Enthusiasm and Desirable Habits of Effective People
• Leadership and Management
• Situational Analysis and Leadership Styles
• Leadership as a Student [discussed in Introduction)
• Leadership as a Forest Scientist
• Leadership as a Teacher and Professor
• Leadership as a Department Head …

The Fierce Green Fire: Vol 5 Issue 10, Wofford College Environmental Studies Program

The Fierce Green Fire

No abstract provided.

Population Genetics Of Seaside Sparrow (Ammodramus Maritimus) Subspecies Along The Gulf Of Mexico., Stefan Woltmann, Phillip C. Stouffer, Christine M. Bergeon Burns, Mark S. Woodrey, Mollie F. Cashner, Sabrina S. Taylor

CREC Publications

Seaside Sparrows (Ammodramus maritimus) along the Gulf of Mexico are currently recognized as four subspecies, including taxa in Florida (A. m. juncicola and A. m. peninsulae) and southern Texas (Ammodramus m. sennetti), plus a widespread taxon between them (A. m. fisheri). We examined population genetic structure of this "Gulf Coast" clade using microsatellite and mtDNA data. Results of Bayesian analyses (Structure, GeneLand) of microsatellite data from nine locations do not entirely align with current subspecific taxonomy. Ammodramus m. sennetti from southern Texas is significantly differentiated from all other populations, but we found evidence of an admixture zone with A. m. …

Evaluation And Application Of Instruments Measuring Spatial Ability And Attitude For College Chemistry Students, Xiaoying Xu

USF Tampa Graduate Theses and Dissertations

Student performance in college chemistry courses remains a concern for educators seeking to help improve the future STEM workforce. Besides math ability and prior chemistry knowledge, spatial ability and attitude toward chemistry have been considered as important factors influencing college chemistry performance. This work includes five studies and uses data collected from instruments to examine the relationships of these two factors - spatial ability and attitude - with student chemistry performance, and provides psychometric evidence for using the Purdue Visualization of Rotations test (ROT) and Attitude toward the Subject of Chemistry Inventory (ASCIv2) to measure these two factors, respectively, in …