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Articles 1 - 10 of 10
Full-Text Articles in Physical Sciences and Mathematics
Anthrax Event Detection: Analysis Of Public Opinion Using Twitter During Anthrax Scares, The Mueller Investigation, And North Korean Threats, Michele E. Miller
Anthrax Event Detection: Analysis Of Public Opinion Using Twitter During Anthrax Scares, The Mueller Investigation, And North Korean Threats, Michele E. Miller
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When people allow fear to drive their decision making, they often make decisions that do more harm than good. Examples of this include stocking up on ciprofloxacin, flooding doctors’ offices and buying black market antibiotics after the anthrax attacks of 2001. Therefore, it is important to be able to address what people are saying when another anthrax attack occurs. Supervised and unsupervised machine learning methodologies can be utilized to detect an event, classify the tweets by event, and to determine the main topics of discussion. Over the period of data collection, twenty events were detected. Three of these events concerned …
The Fate Of Anthropogenic Nitrogen Along Hydrologic Continuums: Patterns Of Transformation And Recycling In A Eutrophic Lake And Coastal Marine Sediments, Daniel K. Hoffman
The Fate Of Anthropogenic Nitrogen Along Hydrologic Continuums: Patterns Of Transformation And Recycling In A Eutrophic Lake And Coastal Marine Sediments, Daniel K. Hoffman
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Eutrophication of aquatic systems can have cascading effects along hydrological continua from watersheds to coasts that result in impaired ecosystem health. In freshwater systems, blooms of toxic, non-nitrogen (N) fixing cyanobacteria (cyanoHABs), such as Microcystis, proliferate due to external loading of chemically reduced forms of N (e.g., ammonium (NH4+) and urea), which promote growth and toxin production. In coastal marine systems, nutrient loading can promote harmful algae blooms and threaten vulnerable, native vegetation, such as seagrasses, which provide valuable ecosystem services but are under threat globally from anthropogenic stressors. This dissertation focuses on NH4+ cycling in the water column of …
Optimization Study Of A Combined Wind-Solar Farm For A Specified Demand, Venkat Siddhartha Rama
Optimization Study Of A Combined Wind-Solar Farm For A Specified Demand, Venkat Siddhartha Rama
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At the present time, using wind and solar energy for producing electricity in the United States is becoming cost competitive. According to Lazard’s 2019 [36] levelized cost of energy (LCOE) analysis of a number of energy sources used for producing electricity in the United States, wind and solar are cheaper than natural gas and coal. While capital, maintenance, operation, and fuel costs are included in LCOE numbers, energy source intermittency is not. Intermittency is an important issue with wind and solar energy sources, but not with natural gas or coal energy sources. Combining wind and solar energy sources into one …
Quantifying Contributions To The Variance Of Permeability And Porosity Within The Western Belt Sandstones Of The Cypress Formation, Illinois Basin, Nathaniel Frederick Dulaney
Quantifying Contributions To The Variance Of Permeability And Porosity Within The Western Belt Sandstones Of The Cypress Formation, Illinois Basin, Nathaniel Frederick Dulaney
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One of the strategies for reducing the emission of the greenhouse gas carbon dioxide (CO2) and mitigating its accumulation into the Earth’s atmosphere is geologic sequestration (GSCO2). This process might be paired with enhanced oil recovery (EOR) within depleted oil reservoirs to provide an economic incentive for GSCO2. Heterogeneity within reservoirs (e.g. spatial differences in entry pressure, permeability, and porosity) can exert significant influence on the dynamics of fluid flow during EOR and GSCO2, and thus on the ultimate success of GSCO2-EOR. The Western Belt sandstones of the Cypress Formation in the Illinois Basin are candidate reservoirs for GSCO2-EOR. Heterogeneity …
Degradation Of Trichloroethene By Radicals Produced By Oxygenation Of Various Reduced Iron Minerals, Jonathon Michael Deeter
Degradation Of Trichloroethene By Radicals Produced By Oxygenation Of Various Reduced Iron Minerals, Jonathon Michael Deeter
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Fe(II)-containing minerals (often as oxides and sulfides) are commonly present in the shallow subsurface and aquifers. Recent studies have shown that Fe(II) can generate reactive oxygen species upon oxygenation. This bench-scale investigation examined the generation of radical species from [Fe(II)]-containing mineral phases when exposed to oxygen. The Fe(II)-minerals in this study were chemically-reduced hydrous ferric oxide (HFO) and goethite, magnetite, and mackinawite (FeS). This research demonstrated that trichloroethene (TCE) can rapidly degrade by radicals produced from Fe(II)-containing oxides if gaseous oxygen is introduced in reactors. In contrast, there was little or no TCE degradation from oxygenation of freshly-prepared ferrous sulfide …
Marine Vertebrate Communities From The Cisuralian Epoch (Permian Period) Of Central North America, Ryan C. Shell
Marine Vertebrate Communities From The Cisuralian Epoch (Permian Period) Of Central North America, Ryan C. Shell
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Marine vertebrates from the Cisuralian Epoch early Permian Period) are rare in the global fossil record. In particular, species-rich faunas from individual localities are poorly represented, with single occurrence localities that do not fully capture faunal tends in marine vertebrate ecology across this interval. This dissertation helps to close this gap by reporting marine vertebrate fossils from five localities across central North America, containing four to 15 unequivocal vertebrate taxa, as well as a new single occurrence locality near the Carboniferous-Permian boundary. This survey includes representatives from the first three of the four Cisuralian faunal stages, and is the result …
Community Structure Has Greater Effect On Water Column Ammonium Cycling Than Nutrients And Temperature In Shallow Lake Mesocosms, Shannon Marie Collins
Community Structure Has Greater Effect On Water Column Ammonium Cycling Than Nutrients And Temperature In Shallow Lake Mesocosms, Shannon Marie Collins
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Harmful algal blooms (HABs) impact lakes worldwide and are caused by excess nitrogen (N) and phosphorus (P) loading from watersheds. Climate warming and nutrient loading effects on N cycling were examined in shallow lake mesocosms in Denmark. N loading to some mesocosms ceased in June 2018 and resumed in June 2019. Ammonium (NH4+) uptake, regeneration, and nitrification and nitrate uptake rates were evaluated. High nutrient, ambient temperature mesocosms exhibited the highest NH4+ cycling rates. Before resumption of N loading in high nutrient mesocosms, NH4+ regeneration supported 46 % of potential microbial NH4+ demand, versus 24 % with N loading. Nutrient …
The Hydrostatics And Hydrodynamics Of Prominent Heteromorph Ammonoid Morphotypes And The Functional Morphology Of Ammonitic Septa, David Joseph Peterman
The Hydrostatics And Hydrodynamics Of Prominent Heteromorph Ammonoid Morphotypes And The Functional Morphology Of Ammonitic Septa, David Joseph Peterman
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Ammonoid cephalopods have chambered shells that regulated buoyancy. The morphology of their shells strongly influenced the physical properties acting on these animals during life. Heteromorph ammonoids, which undergo changes in coiling throughout ontogeny, are the focus of this dissertation. The biomechanics of these cephalopods are investigated in a framework involving functional morphology, paleoecology, and possible modes of life. Constructional constraints were investigated for the marginally-corrugated septal walls within the chambered ammonoid shell. These constraints governed the positive relationship between septal complexity and terminal size. Furthermore, increased septal complexity facilitated liquid retention via surface tension. More complex septa would have increased …
Computational Assessment Of Aortic Valve Function And Mechanics Under Hypertension, Saurav Kadel
Computational Assessment Of Aortic Valve Function And Mechanics Under Hypertension, Saurav Kadel
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Calcific aortic valve disease (CAVD), the most common valvular heart disorder, is associated with complications such as stroke, heart attack, aortic aneurysm, left ventricular hypertrophy, and ultimately death. While hypertension has been identified as a major risk factor for CAVD, the mechanisms by which it may promote calcification are still unknown. Given the sensitivity of valvular tissue to mechanical stress alterations, the hemodynamic abnormalities linked to hypertension may play a role in the development of CAVD. Further, the effects of hypertension on the left ventricular functionality and coronary flow resistance remain largely uninvestigated. Hence, the objectives of this thesis were …
Genetic Analysis Of Snow Leopard Population Employing Next Generation Sequencing For Its Improved Conservation And Management, Safia Janjua
Genetic Analysis Of Snow Leopard Population Employing Next Generation Sequencing For Its Improved Conservation And Management, Safia Janjua
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Snow leopards (Panthera uncia) are an enigmatic, high-altitude species whose challenging habitat, low population densities and patchy distribution have presented challenges for scientists studying its biology, population structure, and genetics. To address these important ecological, conservation, and evolutionary questions, scientists are tailoring laboratory and computational methods to better extract the information from non-invasive samples, only available source of DNA for this species. These samples with very low quantity and quality of DNA, present unique methodological challenges. ddRAD-seq, one of next generation sequencing method is used here to develop reference sequence library for snow leopard using five blood samples from Mongolian …