Physical Sciences and Mathematics Commons^™

Impacts Of The Anomalous Mississippi River Discharge And Diversions On Phytoplankton Blooming In Northeastern Gulf Of Mexico, Brendan O'Connor

USF Tampa Graduate Theses and Dissertations

On April 20, 2010 a tragic explosion aboard the Deepwater Horizon (DWH) drilling rig marked the beginning of one of the worst environmental disasters in history. For 87 days oil and gas were released into the Gulf of Mexico. In August 2010, anomalous phytoplankton activity was identified in the Northeastern Gulf of Mexico, using the Fluorescence Line Height (FLH) ocean color product. The FLH anomaly was bound by approximately 30-28 degrees North and 90 and 86 degrees West and there was a suggestion that this anomaly may have occurred due to the presence of oil. This study was designed to …

Short And Long Term Volcano Instability Studies At Concepción Volcano, Nicaragua, Jose Armando Saballos

USF Tampa Graduate Theses and Dissertations

Concepción is the most active composite volcano in Nicaragua, and is located on Ometepe Island, within Lake Nicaragua. Moderate to small volcanic explosions with a volcanic explosivity index (VEI) of 1-2 have been characteristic of this volcano during the last four decades. Although its current activity is not violent, its volcanic deposits reveal stages of violent activity involving Plinian and sub-Plinian eruptions that deposited vast amounts of volcanic tephra in the Atlantic Ocean. These observations, together with the 31,000 people living on the island, make Concepción volcano an important target for volcanological research.

My research focuses on the investigation of …

Synthesis Of Amphiphilic Α- And Γ-Aapeptides For Antimicrobial, Self-Assembly, And Mineralization Studies, Mohamad N. Amin

USF Tampa Graduate Theses and Dissertations

Seven novel, amphiphilic AApeptides were prepared. Two cationic, lipo-α-AApeptides, NA-75 and NA-77 were found to possess potent antimicrobial activity against Gram-positive bacteria, with almost no hemolytic activity. In addition to NA-75 and 77, four amphiphilic, γ-AApeptides, NA-133, 135, 137, and 139, and one anionic lipo-α-AApeptide, NA-81, were prepared for molecular self-assembly studies, with several interesting nanostructures observed by TEM. Mineralization of calcium carbonate from gaseous CO2 and Ca2+ in the presence of the 7 AApeptide amphiphiles was also observed by optical microscopy. Several AApeptides were found to be able to influence CaCO3 crystal morphology. Another α-AApeptide, NA-63, was synthesized by …

Bayesian Estimation Of Panel Data Fractional Response Models With Endogeneity: An Application To Standardized Test Rates, Lawrence Kessler

USF Tampa Graduate Theses and Dissertations

In this paper I propose Bayesian estimation of a nonlinear panel data model with a fractional dependent variable (bounded between 0 and 1). Specifically, I estimate a panel data fractional probit model which takes into account the bounded nature of the fractional response variable. I outline estimation under the assumption of strict exogeneity as well as when allowing for potential endogeneity. Furthermore, I illustrate how transitioning from the strictly exogenous case to the case of endogeneity only requires slight adjustments. For comparative purposes I also estimate linear specifications of these models and show how quantities of interest such as marginal …

A Latent Mixture Approach To Modeling Zero-Inflated Bivariate Ordinal Data, Rajendra Kadel

USF Tampa Graduate Theses and Dissertations

Multivariate ordinal response data, such as severity of pain, degree of disability, and satisfaction with a healthcare provider, are prevalent in many areas of research including public health, biomedical, and social science research. Ignoring the multivariate features of the response variables, that is, by not taking the correlation between the errors across models into account, may lead to substantially biased estimates and inference. In addition, such multivariate ordinal outcomes frequently exhibit a high percentage of zeros (zero inflation) at the lower end of the ordinal scales, as compared to what is expected under a multivariate ordinal distribution. Thus, zero inflation …

Agricultural And Domestic Waste Contamination In Chilibre Panama And Potential Low-Cost Best Managament Practices, Christopher Etienne Weekes

USF Tampa Graduate Theses and Dissertations

Abstract

Sanitation coverage in the Republic of Panama is 5 to 10 percent below the Millennium Development Goals targets set for the country. Population growth, urbanization, unplanned development and waste mismanagement have resulted in improvised trash sites and waste discharges into river systems that are important components of the biologically diverse natural environment of Panama. The study sought to investigate and estimate the burden of waste from domestic and agricultural sources in three regions of the Chilibre corrigimiento (district). It was hypothesized that the water quality and land cover data would reflect that the most populated region in the study …

The Positive Illusory Bias And Adhd Symptoms: A New Measurement Approach, Sarah A. Fefer

USF Tampa Graduate Theses and Dissertations

The purpose of this study was to investigate perceptions of academic and social competence among adolescents with a continuum of inattentive and hyperactive/impulsive symptoms. Past literature suggests that children with Attention-Deficit/Hyperactivity Disorder (ADHD) display self-perceptions that are overly positive compared to external indicators of competence, a phenomenon that is referred to as the positive illusory bias (PIB; Owens, Goldfine, Evangelista, Hoza, & Kaiser, 2007). The PIB is well supported among children with ADHD, and recent research suggests that the PIB persists into adolescence. To date, research on the PIB has relied on difference scores (i.e., an indicator of competence is …

Hypogene Speleogenesis In The Cerna River Basin, Sw Romania: A Sedimentological, Mineralogical, And Stable Isotopic Approach, Cristina Montana Puscas

USF Tampa Graduate Theses and Dissertations

Ever since it was identified as a speleogenetic process in the Guadalupe Mountains of New Mexico, USA, hypogene speleogenesis has become the focus of numerous research projects aimed at discerning between classical epigene caves and sulfuric acid or thermal caves. The first distinguishing characteristics that were recognized for hypogene caves were passage and cave morphology. The following step was the identification of rare minerals, specific for processes associated to hypogene speleogenesis. One other important step was the recognition of the importance of stable isotopes - mainly of S - in tracing the source of S and the chemical processes affecting …

Computational Approaches For Structure Based Drug Design And Protein Structure-Function Prediction, Sai Lakshmana Kumar Vankayala

USF Tampa Graduate Theses and Dissertations

This dissertation thesis consists of a series of chapters that are interwoven by solving interesting biological problems, employing various computational methodologies. These techniques provide meaningful physical insights to promote the scientific fields of interest. Focus of chapter 1 concerns, the importance of computational tools like docking studies in advancing structure based drug design processes. This chapter also addresses the prime concerns like scoring functions, sampling algorithms and flexible docking studies that hamper the docking successes. Information about the different kinds of flexible dockings in terms of accuracy, time limitations and success studies are presented. Later the importance of Induced fit …

Applications Of Agent Based Approaches In Business: A Three Essay Dissertation, Shankar Prawesh

USF Tampa Graduate Theses and Dissertations

The goal of this dissertation is to investigate the enabling role that agent based simulation plays in business and policy. The aforementioned issue has been addressed in this dissertation through three distinct, but related essays. The first essay is a literature review of different research applications of agent based simulation in various business disciplines, such as finance, economics, information systems, management, marketing and accounting. Various agent based simulation tools to develop computational models are discussed. The second essay uses an agent-based simulation approach to study important properties of the widely used most popular news recommender systems (NRS). This essay highlights …

Ecology Of The Late Neogene Extinctions: Perspectives From The Plio-Pleistocene Of Florida, Shubhabrata Paul

USF Tampa Graduate Theses and Dissertations

The ecological impact of past extinction events is one of the central issues in paleobiology. In face of present environmental changes, a better understanding of past extinctions will enable us to identify the magnitude of biodiversity crises and their underlying processes. The Late Neogene was a time of extraordinary climatic reorganization, including Northern Hemisphere glaciation, the rise of the Central American Isthmus, and associated changes in environmental conditions. Therefore, the Late Neogene extinctions of marine molluscs of South Florida present an ideal platform to examine the interaction between environmental changes and biotic response. In the present study, three different aspects …

Synthesis And Investigations Of Type I And Ii Clathrates Of Group 14, Michael Blosser

USF Tampa Graduate Theses and Dissertations

Clathrates are a class of new materials that have an open-framework structure that allows guest atoms or molecules to be enclosed inside of their polyhedral framework. Varying the number, weight, and size of the guest species in a particular framework allows one to alter the physical properties of the clathrate. This relationship enables one to further the fundamental understanding of the physics and chemistry of the clathrate structure and use this knowledge to "tune" certain properties. This "tunability" of inorganic clathrates is of great interest as it allows one to optimize their physical properties; making them promising candidates for a …

Characterizing Interactions Between Chromophores In Synthetic And Natural Macromolecular Films Via Maldi-Tof, Ibf And Dielectric Analyzer, Parul Jain

USF Tampa Graduate Theses and Dissertations

With the emergence of Matrix Assisted Laser Desorption/Ionization-Time-of-flight as a tool for diagnosis of diseases via proteomics, there is an increasing need for greater sensitivity. Analysis of peptides by MALDI-TOF-MS is affected by sample formulation and spotting onto a MALDI target. This dissertation investigates a novel MALDI sample preparation technique, Induction Based Fluidics (IBF), for depositing precise volumes (pL to nL) of samples onto the target. We have seen that while using IBF, the induced electric field accompanying deposition enhances matrix crystallization yielding smaller crystals with more homogeneity, as compared to conventional manual micropipette (MP) depositions. An investigation of the …

Synthesis And Properties Of Polymer Nanocomposites With Tunable Electromagnetic Response, Kristen Lee Stojak

USF Tampa Graduate Theses and Dissertations

Multifunctional polymer nanocomposites (PNCs) are attractive for the design of tunable RF and microwave components such as flexible electronics, attenuators, and antennas due to cost-effectiveness and durability of polymeric matrices. In this work, three separate PNCs were synthesized. Magnetite (Fe3O4) and cobalt ferrite (CFO) nanoparticles, synthesized by thermal decomposition, were used as PNC fillers. Polymers used in this work were a commercial polymer provided by the Rogers Corporation (RP) and polyvinylidene fluoride (PVDF). PNCs in this thesis consist of Fe3O4 in RP, CFO in RP, and Fe3O4 in PVDF. Characterization techniques for determining morphology of the nanoparticles, and their resulting …

Effectiveness Of Propensity Score Methods In A Multilevel Framework: A Monte Carlo Study, Aarti P. Bellara

USF Tampa Graduate Theses and Dissertations

Propensity score analysis has been used to minimize the selection bias in observational studies to identify causal relationships. A propensity score is an estimate of an individual's probability of being placed in a treatment group given a set of covariates. Propensity score analysis aims to use the estimate to create balanced groups, akin to a randomized experiment. This study used Monte Carlo methods to examine the appropriateness of using propensity score methods to achieve balance between groups on observed covariates and reproduce treatment effect estimates in multilevel studies. Specifically, this study examined the extent to which four different propensity score …

Toward More Composable Software-Security Policies: Tools And Techniques, Daniel Lomsak

USF Tampa Graduate Theses and Dissertations

Complex software-security policies are dicult to specify, understand, and update. The

same is true for complex software in general, but while many tools and techniques exist

for decomposing complex general software into simpler reusable modules (packages, classes,

functions, aspects, etc.), few tools exist for decomposing complex security policies into simpler

reusable modules. The tools that do exist for modularizing policies either encapsulate

entire policies as atomic modules that cannot be decomposed or allow ne-grained policy

modularization but require expertise to use correctly.

This dissertation presents a policy-composition tool called PoliSeer [27, 26] and the

PoCo policy-composition software-security language. PoliSeer is …

Do Personality Tests Have A Place In Academic Preparation Of Undergradute Hospitality Students, Gunce Malan

USF Tampa Graduate Theses and Dissertations

This is a descriptive study that poses the questions and discussion regarding use of personality tests in prediction of future job performance of the current undergraduate hospitality students. A gap exists between the perception of the skills and competencies of high performers and the perception of hospitality students (Berezina et al., 2011; Malan, Berezina & Cobanoglu, 2012). The purpose of this study is to investigate if personality tests will help in predicting the success of students in their preferred job setting as compared to current high performers (managers).

The use of personality tests increased substantially after 1988, when the government …

Biochemical Aspects Of The Thermal Sensitivity And Energy Balance Of Polar, Tropical And Subtropical Teleosts, Eloy Martinez

USF Tampa Graduate Theses and Dissertations

The maintenance of a functional energy balance in ectothermic fauna could be challenging in a thermally disparate environment. Biochemical adaptations at the enzyme and membrane levels allows for a set compensatory mechanism that allow the individual to maintain an energetic surplus, thus allocating energy for growth and reproduction. The present work describes how the energetic machinery in the cell, particularly the mitochondrion, could be affected by temperature changes. More specifically, this work aimed to determine how environmental temperature affects the mitochondria energetic performance of fishes from disparate thermal regimes.

Mitochondrial ATP production efficiency was evaluated in fishes from polar, tropical …

Dynamic Processes In Network Goods: Modeling, Analysis And Applications, Arnut Paothong

USF Tampa Graduate Theses and Dissertations

The network externality function plays a very important role in the study of economic network industries. Moreover, the consumer group dynamic interactions coupled with network externality concept is going to play a dominant role in the network goods in the 21st century. The existing literature is stemmed on a choice of externality function with certain quantitative properties. The utility function coupled with the network externality function is used to investigate static properties of rational equilibrium. The aim of this work is to systematically initiate a development of quantitative effects of the concept of network externality and its influence on the …

Light-Environment Controls And Basal Resource Use Of Planktonic And Benthic Primary Production, Kara Radabaugh

USF Tampa Graduate Theses and Dissertations

Consumers in marine and estuarine environments have a strong reliance on planktonic and benthic primary production. These two basal resources form the foundation of aquatic food webs, yet the abundance of phytoplankton and benthic algae are frequently inversely related due to competition for light and nutrients. As a result, optimal habitats for benthic and planktonic consumers vary spatially and temporally. To investigate these trends, three studies were conducted focusing on light attenuation and basal resources in a bay, river, and on a continental shelf.

δ¹³C and δ¹⁵N stable isotopes can be used as endogenous tracers to …

Defining And Preventing Code-Injection Attacks, Donald Ray

USF Tampa Graduate Theses and Dissertations

This thesis shows that existing definitions of code-injection attacks (e.g., SQL-injection attacks) are flawed. The flaws make it possible for attackers to circumvent existing mechanisms, by supplying code-injecting inputs that are not recognized as such. The flaws also make it possible for benign inputs to be treated as attacks. After describing these flaws in conventional definitions of code-injection attacks, this thesis proposes a new definition, which is based on whether the symbols input to an application get used as (normal-form) values in the application's output. Because values are already fully evaluated, they cannot be considered ``code'' when injected. This simple …

Turning Water Into Wine: The Political Economy Of The Environment In Southern California's Wine Country, Jason Simms

USF Tampa Graduate Theses and Dissertations

This dissertation examines questions of water sustainability in contexts of wine production and state-led neoliberal development in the Temecula Valley, southern California, where wine tourism is at present being harnessed as an engine of economic growth. Natural and anthropogenic forces, such as global climate change, desertification, urban development, and the marketization and commodification of natural resources, affect the distribution and availability of water throughout the globe. As a result, the use of water, and associated political and environmental processes and consequences, in the production of global commodities, including wheat, citrus, and coffee, recently have come under increased scrutiny. Given wine's …

Asymmetric Nitrene Transfer Reactions With Azides Via Co(Ii)-Based Metalloradical Catalysis (Mrc), Jingran Tao

USF Tampa Graduate Theses and Dissertations

Asymmetric nitrene transfer reactions via metalloradical catalysis (MRC) with

azides has attracted research interest because of its fundamental and practical importance.

The resulting nitrogen-containing units are recurrent motifs in biologically important

molecules and can serve as versatile precursors in organic synthesis.

The [Co(D2-Por*)] have emerged as a new class of catalysts for asymmetric

aziridination and C-H amination. These metalloradical catalysts have been shown to be

highly effective for the asymmetric intermolecular aziridination of a broad scope of

substrates with different classes of azides with excellent to good enantioselectivity. The

intramolecular C-H amination utilizing various azides can allow for the construction …

Automatic Identification Of Points Of Interest In Global Navigation Satellite System Data: A Spatial Temporal Approach, Khoa Anh Tran

USF Tampa Graduate Theses and Dissertations

In addition to the emergence of smartphones and tablets in recent years, the rise of Global Navigation Satellite Systems (GNSS) has allowed mobile tracking applications to become popular and be put into many uses. Analyzing tracking records to identify points of interest (POIs) is useful for both prediction applications and research such as human behavior analysis, transportation planning, and especially travel surveys. Past research in travel surveys has shown that a GPS mobile phone-based survey is a useful tool for collecting information about individuals. Moreover, a passive travel survey collection is preferred to an active travel survey method by the …

Flexible Urban Water Distribution Systems, Seneshaw Amare Tsegaye

USF Tampa Graduate Theses and Dissertations

With increasing global change pressures such as urbanization and climate change, cities of the future will experience difficulties in efficiently managing scarcer and less reliable water resources. However, projections of future global change pressures are plagued with uncertainties. This increases the difficulty in developing urban water systems that are adaptable to future uncertainty.

A major component of an urban water system is the distribution system, which constitutes approximately 80-85% of the total cost of the water supply system (Swamee and Sharma, 2008). Traditionally, water distribution systems (WDS) are designed using deterministic assumptions of main model input variables such as water …

Boolean Partition Algebras, Joseph Anthony Van Name

USF Tampa Graduate Theses and Dissertations

A Boolean partition algebra is a pair $(B,F)$ where $B$ is a Boolean

algebra and $F$ is a filter on the semilattice of partitions of $B$ where $\bigcup F=B\setminus\{0\}$. In this dissertation, we shall investigate the algebraic theory of Boolean partition algebras and their connection with uniform spaces. In particular, we shall show that the category of complete non-Archimedean uniform spaces

is equivalent to a subcategory of the category of Boolean partition algebras, and notions such as supercompleteness

of non-Archimedean uniform spaces can be formulated in terms of Boolean partition algebras.

Algorithms And Data Structures For Efficient Timing Analysis Of Asynchronous Real-Time Systems, Yingying Zhang

USF Tampa Graduate Theses and Dissertations

This thesis presents a framework to verify asynchronous real-time systems based on model checking. These systems are modeled by using a common modeling formalism named Labeled Petri-nets(LPNs).

In order to verify the real-time systems algorithmically, the zone-based timing analysis method is used for LPNs. It searches the state space with timing information (represented by zones). When there is a high degree of concurrency in the model, firing concurrent enabled transitions in different order may result in different zones, and these zones may be combined without affecting the verification result. Since the zone-based method could not deal with this problem efficiently, …

Statistical Topics Applied To Pressure And Temperature Readings In The Gulf Of Mexico, Malena Kathleen Allison

USF Tampa Graduate Theses and Dissertations

The field of statistical research in weather allows for the application of old and new methods, some of which may describe relationships between certain variables better such as temperatures and pressure. The objective of this study was to apply a variety of traditional and novel statistical methods to analyze data from the National Data Buoy Center, which records among other variables barometric pressure, atmospheric temperature, water temperature and dew point temperature. The analysis included attempts to better describe and model the data as well as to make estimations for certain variables. The following statistical methods were utilized: linear regression, non-response …

Exploring Local Food System Practices And Perceptions: Insights From Florida's Snap-Authorized Farmers' Markets, Leslie Babiak

USF Tampa Graduate Theses and Dissertations

Despite heightened interest in creating local food systems that enhance health of ecologies, economies, and all members of communities, the public space of farmers' markets is far less than inherently equitable. This is particularly concerning given America's unprecedented crisis of food hardship and related disease, which disproportionately affects lower income populations. This research addresses the social justice implications of SNAP (food stamp) operations for locally oriented food systems. Pioneering practices of three of Florida's SNAP-authorized farmers' markets, and the attitudes and behaviors of one-hundred-seventy-six market patrons, were explored through customer surveys, market manager interviews, and environmental assessments. Qualitative and quantitative …

Model Pt- And Pd-Based Electrocatalysts For Low Temperature Fuel Cells Applications, Selasi Ofoe Blavo

USF Tampa Graduate Theses and Dissertations

In the search for alternative energy technologies, low temperature fuel cells continue to feature as technologies with the most promise for mass commercialization. Among the low temperature fuel cells, alkaline and proton exchange membrane fuel cells are the most popular. Alkaline fuel cells have typically been used for water generation as well as auxiliary power for space shuttles. Their bulkiness however makes them undesirable for other applications, especially in automobiles, where there is a great demand for alternative technologies to internal combustion engines. Proton exchange membrane fuel cells on the other hand possess numerous qualities including their compact size, high …