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Modelling the Evolution of Outflow Troughs in NGC3783
No full textUsing archival spectra from the Cosmic Origins Spectrograph (COS) and Space Telescope Imaging Spectrograph (STIS) on board the Hubble Space Telescope over a time span of 16 years, we explore the variability of absorption troughs in lines of C IV from outflowing material of NGC3783. Using templates of earlier epoch troughs, we visually determine trough structure changes. We observe changes in the optical depths and/or covering factors, which is indicative of bulk motion of material across the line-of-sight. Furthermore, we use troughs of doublets to model blended troughs. We find that the blended troughs cannot be modelled fully by the corresponding doublet troughs, which implies that there must be additional absorbing material
A FIRMAMENT IN THE MIDST OF THE WATERS**
No full textThe Georgia Southern University archaeology program\u27s long term research goals include exploration and documentation of sites in the Atlantic Coastal Plain, especially in areas unknown or little known through professional survey. Recent and ongoing work by the authors and our field school students have revealed intriguing evidence of substantial settlement in Georgia\u27s early colonial period, including the construction of earthworks in a complex of streams tributary to the Savannah River. Our analysis efforts of this site and its occupants bear directly on questions of conflict, economy, ethnicity, and nation building in an out-of-the-way place
FOSSIL SHARKS AND RAYS FROM A NEW LOCALITY IN WILKINSON COUNTY, GEORGIA
No full textFossils of marine organisms have been described from Eocene units of the southeast. In Georgia, they are generally found within the quartz dominated nearshore deposits of the Clinchfield Formation of the Barnwell Group. Recent exploration of a fossiliferous horizon in an active kaolin mine in Wilkinson County, Georgia has produced an array of marine fossils. The fossils were recovered by surface collecting overburden sediments exposed by mining operations. Thus far, the collection includes bivalves, gastropods, echinoderms, teeth of chondrichthyans, many vertebrae of osteichthyans, at least one species of turtle (Trionychidae) represented by multiple shell fragments, several vertebrae from an extinct “sea snake” (Pterosphenus), and two cetacean vertebrae. Here we describe the chondrichthyans. Based on frequency of occurrence, the collection is dominated by shark teeth belonging to the Sand Tiger Shark (Charcharis). Tiger Sharks (Galeocerdo), Snaggletooth Sharks (Hemipristis), Angel Sharks (Squatina), Sawfish Sharks (Pristis), Extinct Sawfish (Propristis), and Megatooth Sharks (Carcharocles) are also present. Rays are represented by a number of dental plates, isolated teeth, and tail spines (cf. Myliobatis). Most of these taxa have been interpreted as shallow water, near shore animals. These fossils add to our knowledge of the geographic distribution of these taxa and enhance our understanding of the paleoenvironments of central Georgia during the Late Eocene
Calculation of the Anodic Layer on Anodized Niobium
No full textAnodized niobium surfaces are used in particle accelerators for construction of superconducting cavities. The thickness of the anodized layer in these cavities is directly proportional to the voltage used to apply the layer. In this project, we will show how the thickness and voltage relate to each other and describe a program we are developing to allow us to find out the thickness of any layer that has accrued on the surface during the anodizing process by inputting the applied voltage into our cod
Characterization of Anodized Niobium Surfaces
No full textAnodization is a technique that is utilized for a number of different situations, including protection of surfaces or formation of anodic layers on particle accelerator walls. Once a metal has been anodized, the oxide layer can affect some of the characteristics of the surface of the metal sample, most notably, the color. By anodizing a metal at a certain voltage, we can manipulate the wavelengths of light reflected or absorbed by the surface of the sample. In this presentation we will show how the anodizing process has changed the color of niobium metal surface and describe the relationship between the observed color and the thickness of the niobium-oxide layer
DEVELOPMENT OF AN AUTOGRADER FOR JAVA PROGRAMS
No full textGrading computer programs for student submissions in introductory computer science classes is a long and laborious task if done by hand. Autograding software are available for purchase and for free; however, they all have limitations. We have developed a program that is quite general and will work for autograding any Java program. The only requirement is that the exact name of classes and signature of methods must be adhered to by the students. An instructor who uses the autograder must do three things in advance of grading. First, they must have a correct implementation of the program, called the solution. Next, the instructor must write test cases and assign point values in a particular format. Finally, the instructor must run the autograder against the solution in order to obtain the correct results. Then, the instructor runs the autograder against each student solution. The autograder produces a report for each student showing the expected and actual output for each test case, whether the test succeed or failed, the incremental points awarded, and the final tally of points
ORCHID BEE COMMUNITY STRUCTURE IN OPEN AND FORESTED SITES IN A TROPICAL CLOUD FOREST REGION OF COSTA RICA
No full textWe examined the structure of orchid bee (Apidae: Euglossini) communities in different habitat types in the tropical cloud forest region near San Luis, Monteverde, Costa Rica. Because previous studies have shown that orchid bee community composition can differ in habitats with varying levels of disturbance, we investigated potential differences in orchid bee community structure between open sites (unforested areas near buildings and/or roads) and forested sites (areas of dense understory and canopy vegetation) over a 5-day period in June 2019. 10 traps were placed in both open and forested areas and all traps were at least 100 m apart. Traps consisted of 3.8 L containers with a single opening and were baited with a chemical attractant that was replenished daily. Traps were checked each day and all orchid bees collected were euthanized and identified to species. Shannon diversity, species evenness, and species abundance were compared between open and forested sites using t-tests, though no significant differences were found. Overall richness was higher in forested areas (17 species vs. 13 species in open areas). We also found more endemic species and fewer widespread species in the forested areas as compared to open sites. Differences in species composition were observed between habitat types; for example, Euglossa imperialis dominated open areas while Euglossa dilemma dominated forested areas. Though short-term, our study is part of an ongoing long-term study on the potential effects of human disturbances such as habitat fragmentation in tropical cloud forest. Our results will be useful for informing conservation planning to minimize impacts of human activity in a region with high biodiversity
EFFECT OF SUGAR ENRICHED DIET ON MOTOR SKILLS AND COLD TOLERANCE BEHAVIOR OF DROSOPHILA**
No full textDrosophila is extensively studied in genetics, but the effect of a sugar enriched diet on motor skills and cold tolerance in Drosophila are less understood. To understand the correlation between sugar enriched diet and behavior (motor skills and tolerance to cold), we studied two strains of Drosophila melanogaster; wild type and simW501. Both strains of flies were raised up to 5 generations on 30% and 40% sugar enriched food media. 20 Flies from each population were used to test the climbing ability, bang sensitivity to see the effect on motor skills. In order to test cold tolerance, 20 flies from each population were exposed to minus 6° C for one hour and then placed them at 25° C for 24 hours for recovery. After the recovery period, we recorded survival flies. We replicate each assay twice per sex
DIGITAL TEXTBOOK FOR SURVEY OF CHEMISTRY I**
No full textModern age students need knowledge in a different format, in terms of imagination, visualization, practice, mastery and preferably on mobile electronic devices. A big obstacle for student success in higher education is high tuition cost as well as skyrocketing textbook price. The objective of this project is to prepare an open source free educational resource (OER) for the non-science major students who are taking college level Survey of Chemistry I Course. The goal is to prepare a supplementary course material with all needed benefits of the regular textbook to assist students in reading and understanding the material to succeed in this course. The ebook includes several simulation based learning activities tied to interactive questions and quizzes, videos. High level of visual content of the concept is emphasized in concept building. All the visual images and simulations used are taken from free available OERs. PHET simulation, Molecular Workbench, Chemistry Solutions, Merlot, Chem Collective etc. are some of simulation and video sites used in this ebook. This project has been funded by Affordable Learning Georgia, Textbook Transformation Grant, round 12. Content development of the ebook was completed by Spring 2019 and implemented in classroom in Fall 2019. Total five different sections across the campus used the ebook and positive students feedback were obtained. A separate website was created for teaching using the ebook https://chemistrylearningbydoing.org. Students registered on the website and enrolled in particular instructor’s batch. More than 150 students used the website as textbook. Students overall performance was recorded and compared with previous term. Students quiz and test performance increased by more than 14% and 21% for some classes. Comparison of final exam grade is yet to be determined at this moment. This ebook will be available for free for public use under Georgia Public Library System
INVESTIGATION OF REACTION CONDITIONS FOR VANADIUM-CATALYZED CONVERSION OF BIOMASS TO FORMIC ACID**
No full textCellulose and glucose are among the most abundant forms of biomass, and as such, are being sought after as renewable resources for the production of feedstock chemicals and fuels. Formic acid (FA) is one possible organic product that can be derived from these carbohydrates, which can be further converted into useful chemicals such as hydrogen with an appropriate catalyst. Currently, the techniques used in the conversion of biomass into FA require high temperatures (ca. 160 °C) and pressures (ca. 30 atm), and specialized apparatus in order to safely operate under these extreme conditions. However, we have previously found that formic acid can be successfully generated at lower temperatures (ca. 100 °C) and pressures (ca. 10 atm). In this work, we investigated the effect of temperature, pressure, and concentration on the conversion of cellulose and glucose into FA in the presence of sulfuric acid, oxygen, and catalytic amounts of sodium metavanadate (NaVO3)