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Interference Of Light In Multilayer Metasurfaces: Perfect Absorber And Antireflection Coating, Khagendra Prasad Bhattarai

USF Tampa Graduate Theses and Dissertations

We have studied several metamaterials structures with multiple layers by explaining them theoretically and verifying experimentally. The engineered structures we have designed work either as a perfect absorber or antireflection coating. The multilayer model as we call it Three Layer Model (TLM) has been developed, which gives the total reflection and transmission as a function of reflection and transmission of individual layers. By manipulating the amplitude and phase of the reflection and the transmission of the individual layers, we can get the required functionality of the optoelectronic devices. To get zero reflection in the both perfect absorber and the antireflection …

Perception Of School Staff Regarding The Effectiveness Of A Youth Mental Health Program In Schools, Hiba Chehaib Chehaib

USF Tampa Graduate Theses and Dissertations

There is an ongoing debate about how to serve the number of students that are affected by mental health problems. Some schools have moved toward implementing whole school programs. The purpose of these programs is to teach adults who directly interact with school age children, such as parents, family members, caregivers, teachers, school staff, and caring citizens how to respond to an adolescent that is facing a crisis or a mental health challenge. The purpose of this study is to evaluate the perceived effectiveness of such a program. The goals of this study are to (a) determine the short-term outcomes …

Extending The Model With Internal Restrictions On Item Difficulty (Mirid) To Study Differential Item Functioning, Yong "Isaac" Li

USF Tampa Graduate Theses and Dissertations

Differential item functioning (DIF) is a psychometric issue routinely considered in educational and psychological assessment. However, it has not been studied in the context of a recently developed componential statistical model, the model with internal restrictions on item difficulty (MIRID; Butter, De Boeck, & Verhelst, 1998). Because the MIRID requires test questions measuring either single or multiple cognitive processes, it creates a complex environment for which traditional DIF methods may be inappropriate. This dissertation sought to extend the MIRID framework to detect DIF at the item-group level and the individual-item level. Such a model-based approach can increase the interpretability of …

An Exploration Of Self-Compassion And Wellness Behaviors Among Practicing School Counselors, Anjanette Todd

USF Tampa Graduate Theses and Dissertations

According to the American School Counseling Association (ASCA, 2010), school counselors are charged with meeting the academic, social/emotional and career needs of all students (2010). In addition, school counselors serve as the front line in dealing with trauma and crisis in their schools. Those counselors who understand the importance of their own wellness and practice healthy lifestyle behaviors are better equipped to meet these demands.

Unfortunately, not all school counselors are practicing what they advocate for their students relative to promoting wellness in their own lives (O'Halloran & Linton, 2000). This lack of congruence, where school counselors are not modeling …

Neuropeptide Modulation Of The Large Conductance Potassium (Bk) Channel In The Auditory System: Therapeutic Implications For Age-Related Hearing Loss, Ellliott James Brecht

USF Tampa Graduate Theses and Dissertations

The auditory temporal processing deficits associated with age-dependent hearing decline have been increasingly attributed to issues beyond peripheral hearing loss. Age-related hearing loss (ARHL), also known as presbycusis, is linked with changes in the expression of both excitatory and inhibitory neurotransmitters in the central auditory system. There are also age-related changes in the expression and function of the ion channels which mediate action potential firing. The slow, Ca²⁺ activated, K⁺ channels of the BK-type are essential in controlling both neurotransmitter release and neural communication via alteration of action potential durations, firing frequency, and neural adaptation. There are many …

On The Conformational Dynamics Of Dna: A Perspective From Molecular Dynamics Simulations, Ning Ma

USF Tampa Graduate Theses and Dissertations

The main focus of my dissertation is on the conformational motion of DNA, studied by applying tools from the computational chemistry field. In addition, studies of relative α- and 310 helical stabilities in peptides/mini-proteins, and a molecular flooding study of the retinoid X-receptor as part of a continuing drug design effort are presented. In molecular biology, it has been well known that sequence determines structure, and structure controls function. For proteins or DNA to work properly, the correct configuration is required. Mutations may alter the structure, which can cause malfunction. Non-mutational effects, such as a change in environment may also …

The Sustainability Of Ion Exchange Water Treatment Technology, Adib Amini

USF Tampa Graduate Theses and Dissertations

This research investigated using a life cycle environmental and economic approach to evaluate IX technology for small potable water systems, allowing for the identification and development of process and design improvements that reduce environmental impacts and costs. The main goals were to evaluate conventional IX in terms of life cycle environmental and economic sustainability, develop a method for improving designs of IX systems from a environmental and economic sustainability standpoint, evaluate potential design improvements, and make the research findings accessible to water professionals through user-friendly tools and frameworks that take into account their feedback. This research provides an understanding, from …

Dynamics Of Multicultural Social Networks, Kristina B. Hilton

USF Tampa Graduate Theses and Dissertations

Historically human endeavors around the globe are in search of bilateral relationships. Knowledge and commerce has played a very significant role in increasing the ability for humans to connect for the betterment of the human species. As the means of communication improve, mutual benefits to the community as a whole also increase. Moreover, the benefits are filtered down to members of the overall community. Recent advancement in electronic communication technologies and in knowledge, in particular, physical, chemical, engineering and medical sciences and philosophies, have facilitated nearly instantaneous multi-cultural interactions. Local problems and solutions have become global. This has generated a …

Plasmonic Stimulation Of Electrically Excitable Cells, Fnu Parveen

USF Tampa Graduate Theses and Dissertations

There is a compelling need for the development of new sensory and neural prosthetic devices which are capable of more precise point stimulation. Current prosthetic devices suffer from the limitation of low spatial resolution due to the non-specific stimulation characteristics of electrical stimulation, i.e., the spread of electric fields generated. We present a visible light stimulation method for modulating the firing patterns of electrically-excitable cells using surface plasmon resonance phenomena. In in-vitro studies using gold (Au) nanoparticle-coated nanoelectrodes, we show that this method (substrate coated with nanoparticles) has potential for incorporating the technology into neural stimulation prosthetics, such as cochlear …

The Potential Role Of Antiretroviral Efavirenz In Hiv Associated Neurocognitive Disorders, Lecia Ashanna Moya Brown

USF Tampa Graduate Theses and Dissertations

The prevalence of milder forms of HIV-associated neurocognitive disorders (HAND) is rising despite combination antiretroviral therapy (cART). Efavirenz (EFV) is among the most commonly used antiretroviral drugs globally, but causes neurological symptoms that may interfere with adherence and reduce tolerability, and may have central nervous system (CNS) effects that contribute in part to HAND in patients on cART. Thus we evaluated a commonly used EFV containing regimen: EFV/zidovudine (AZT)/lamivudine (3TC) in murine N2a cells transfected with the human “Swedish” mutant form of amyloid precursor protein (SweAPP N2a cells) to assess for promotion of amyloid-beta (Aβ) production (Chapter 3). Treatment with …

The Dynamics Of The L2 Motivational Self System Among Saudi Study Abroad Students, Fahad Alharbi

USF Tampa Graduate Theses and Dissertations

Adult second language acquisition takes time over an extended period of time during which the L2 motivation of learners goes through periods of ups and downs. Dörnyei, MacIntyre and Henry (2015) recognized the inherently dynamic nature of L2 motivation and called for adopting the Complex Dynamic System Theory (CDST) when studying this phenomenon. While using a CDST perspective, this mixed method study drew on Dörnyei’s (2009b) model of the Motivational Self System to examine the L2 motivation of 86 Saudi study-abroad students. Also, the construct of the Anti-ought to Self (Thompson, 2015) and aspects of the Appraisal Theory (Schumann, 2001) …

Quantity Trumps Quality: Bayesian Statistical Accumulation Modeling Guides Radiocarbon Measurements To Construct A Chronology In Real-Time, Devon Robert Firesinger

USF Tampa Graduate Theses and Dissertations

The development of an accurate and precise geochronology is imperative to understanding archives containing information about Earth’s past. Unable to date all intervals of an archive, researchers use methods of interpolation to approximate age between dates. Sections of the radiocarbon calibration curve can induce larger chronological uncertainty independent of instrumental precision, meaning even a precise date may carry inflated error in its calibration to a calendar age. Methods of interpolation range from step-wise linear regression to, most recently, Bayesian statistical models. These employ prior knowledge of accumulation rate to provide a more informed interpolation between neighboring dates. This study uses …

Scalable Unsupervised Learning With Game Theory, Alireza Chakeri

USF Tampa Graduate Theses and Dissertations

Recently dominant sets, a generalization of the notion of the maximal clique to edge-weighted graphs, have proven to be an effective tool for unsupervised learning and have found applications in different domains. Although, they were initially established using optimization and graph theory concepts, recent work has shown fascinating connections with evolutionary game theory, that leads to the clustering game framework. However, considering size of today's data sets, existing methods need to be modified in order to handle massive data. Hence, in this research work, first we address the limitations of the clustering game framework for large data sets theoretically. We …

Mass-Spectrometry Based Proteomics Of Age-Related Changes In Murine Microglia, Antwoine Flowers

USF Tampa Graduate Theses and Dissertations

The last century has seen a steady increase in the extension of the average lifespan. This has concomitantly produced higher incidences of age-related chronic degenerative diseases like Alzheimer’s and Parkinson’s diseases. Age is the single greatest risk factor for the development of not just these degenerative conditions but cancer as well. The aged niche undergoes a number of maladaptive changes that allow underlying conditions to present and progress. Exactly which changes, contribute to the progression of which disease is currently an area of intense study. However, these answers often present therapeutic targets for disease prevention. Age is characterized by a …

Analysis Of Antibody-Induced Plasmodium Falciparum Sporozoites Through Scanning Electron Microscopy, Sagorika Bera

USF Tampa Graduate Theses and Dissertations

Malaria is a devastating disease that continues to affect millions of people worldwide every year. Specifically, Plasmodium falciparum is the most common human malaria parasite, particularly in sub-Saharan Africa. P. falciparum causes the most malignant and debilitating symptoms with the highest mortality and complication rates. Even with the worldwide efforts of many researchers and organizations, the road to discovering a vaccine has been difficult and challenging. Due do to the improvements in in vitro liver stage assays as well as rodent models of mammalian malaria, pre-erythrocytic stages of malaria have become a more accessible target for experimental studies. These vaccine …

Using Remote Sensing To Evaluate Wetland Recovery In The Northern Tampa Bay Area Following Reduction In Groundwater Withdrawals, Amor Elder

USF Tampa Graduate Theses and Dissertations

In the past, the Northern Tampa Bay Area (NTBA) wetlands saw severe declines in hydrologic conditions due to excessive groundwater withdrawal rates. Eventually these rates were reduced to allow the wetlands to recover. To monitor this recovery, the Southwest Florida Water Management district (SWFWMD) set up a fieldwork based scoring methodology, called the Wetlands Assessment Procedure (WAP). WAP has been used in many studies of the area since groundwater withdrawal reductions; with many of those studies finding the recovery to be mixed at best. However, these studies were very limited in the number of wetlands they could assess due to …

Abundance And Habitat Preferences Of Introduced Muscovy Ducks (Cairina Moschata), Jacqueline Marie Perry Cahanin

USF Tampa Graduate Theses and Dissertations

Muscovy ducks are native only to Central and South America, Mexico, and parts of southern Texas and are considered invasive in some areas outside of their native range. Although they have been introduced worldwide, they remain largely unstudied. The primary focus of this study was to relate Muscovy duck abundance to habitat characteristics of wetlands in Tampa, Florida. Muscovy abundance was measured using point count methods at 21 wetland sites that occur within an eight km radius of the University of South Florida’s main campus. Habitat features at these sites were assessed using field methods and Geographic Information Systems (GIS) …

A Novel Approach To The Discovery Of Natural Products From Actinobacteria, Rahmy Tawfik

USF Tampa Graduate Theses and Dissertations

Actinobacteria, primarily the genus Streptomyces, have led to the development of a number of antibiotics, which result from their secondary metabolites or modified derivatives. Secondary metabolite production can result from competition with neighboring microbes in an effort to disrupt growth, aiding in the competition for vital nutrients in impoverished conditions. Such secondary metabolites have the potential to affect a plethora of cellular functions in target cells, including, cell wall development, protein synthesis, protein function and fatty acid synthesis/metabolism. Due to the pandemic spread of antibiotic resistant bacteria, it is imperative to continue the search for new therapeutic agents …

Volunteer Tourism: Fulfilling The Needs For God And Medicine In Latin America, Erin Howell

USF Tampa Graduate Theses and Dissertations

This study seeks to understand how short-term medical missions fulfill health needs for their recipients in Honduras, and how in turn, mission participants experience need fulfillment as well. By using the theoretical concept of co-construction of health to see how health needs are or are not met, I conducted a thematic analysis of the Baptist Medical and Dental Mission International (BMDMI) resulting in the following themes: 1.) Mission workers receive fulfillment from their experiences in the mission field. 2.) Mission recipients receive partial fulfillment of needs from the mission. 3). Through a calling, missions are a means to an end. …

Taxonomy, Ecology, And Behavior Of The Kleptoplastic Sea Slug Elysia Papillosa, William Alan Gowacki

USF Tampa Graduate Theses and Dissertations

Sacoglossan sea slugs are one of the best known examples of specialist herbivores in the marine environment and can be found strongly associated with their algal hosts and food sources. Perhaps the most intriguing characteristic of many sacoglossans is their ability to sequester functional chloroplasts from their algal food sources in a process called kleptoplasty. Despite this, there continues to be issues regarding taxonomic identification of species. In turn, the ecological characteristics of many of these slugs, such as algal host and food source preference, as well as their behavioral aspects, have received little attention. A prime example of these …

Development Of Tools For Stable Transfection In The Human Filarial Parasite Brugia Malayi Via The Piggybac Transposon System, Johan Chabanon

USF Tampa Graduate Theses and Dissertations

Brugia malayi is one of three species of nematode known to cause lymphatic filariasis (LF) in humans. LF infects over 120 million people, causing debilitating disease. Various global programs have been launched in the past 20 years to eliminate LF. These programs have greatly scaled up the resources and efforts allocated to halting the transmission and reducing disease burden. Only a few drugs are used to treat LF, and resistance is thus a devastating possibility. Research aimed at identifying new drug targets could therefore prove essential in elimination of LF.

Genetic manipulation of B. malayi has been limited to transient …

Occupational Noise Exposure Evaluation Of A Group Of Groundskeepers At A University Campus, Monica Elisa Garcia

USF Tampa Graduate Theses and Dissertations

Every year, twenty-two million workers are exposed to potentially damaging noise at work. Last year, U.S. businesses paid more than $1.5 million in penalties for not protecting workers from noise. (OSHA, 2016). In the United States ten million people have some kind of noise related hearing loss (CDC, 2016) and noise damage to the ear may not be detected until it is great enough to cause hearing impairment.

Grounds keeper’s functions consist of a variety of activities that require the use of powered tools such as mowers, riding mowers, leaf blowers, pressure washers, trimmers/edgers and chainsaws. OSHA has stated that …

Latino Subgroups Political Participation In American Politics: The Other Latinos’ Electoral Behavior, Angelica Maria Leon Velez

USF Tampa Graduate Theses and Dissertations

This thesis explores the impact of Latinidad in Latino political participation, especially in regard to voting behavior. Although Latinos often have been portrayed as a decisive electoral group, the reality is they have not fulfilled the expectations imposed upon them. Therefore, I argue Latinos with different levels of group consciousness will engage differently in politics, which affects the voting statistics of the ethnicity in Censuses, reports and surveys. The use of pan-ethnic terms and the constant stereotypes of Latinos all being “the same,” has caused separation rather than cohesiveness within the minority group, which has resulted in low political engagement. …

Development Of A Transfection System For The Free-Living Amoeba Naegleria Fowleri Using The Piggybac Vector, Kati Räsänen

USF Tampa Graduate Theses and Dissertations

Naegleria fowleri is a free-living amoeba that causes primary amoebic meningoencephalitis (PAM). In the United States, there are between 0-8 cases of PAM per year, with approximately 98% of cases resulting in death. High case fatality and limited treatment options highlight the need for better understanding of this organism in terms of its biology and pathogenicity. Transfection is a useful tool that allows for the study of gene function, but at present no transfection systems have been established for N. fowleri. This study attempts to establish a transfection system for N. fowleri using the piggyBac vector, with the hope of …

Light Olefin Production By Cracking Nannochloris Oculata Microalgae Using Aluminosilicate Catalysts, Gaurav Goyal

USF Tampa Graduate Theses and Dissertations

The global demand and sustainability concerns for producing light olefins encouraged researchers to look for an alternative and sustainable feedstock. Alkenes, such as ethene, propene and butene, are known as light olefins. Olefins are the backbone of the chemical industry because they serve as the chemical building blocks for the manufacture of polymers, fibers, and numerous organic chemicals. Feedstocks such as naphtha, natural gas and liquefied petroleum gas (LPG) are currently used for producing light olefins, but they are non-renewable and hence unsustainable. In contrast, biomass as a potential feedstock for the production of fuels and chemicals is renewable. Microalgae, …

Effects Of Microstructure And Alloy Concentration On The Corrosion And Tribocorrosion Resistance Of Al-Mn And We43 Mg Alloys, Hesham Y. Saleh Mraied

USF Tampa Graduate Theses and Dissertations

The design of new engineering materials resistant to both wear damage and corrosion degradation becomes increasingly demanding in complex service conditions. Unfortunately, there is typically a tradeoff between wear and corrosion resistance, even for important passive metals such as Al alloys. This is because the presence of precipitates hardens the material but at the same time lead to unfavorable galvanic coupling between the precipitates and the matrix, resulting in accelerated corrosion. This work showed that Al (or Mg) supersaturated solid solution formed using non-equilibrium methods exhibited enhanced corrosion resistance without compromising strength. For Al, alloying with Mn up to ~ …

Latitudinal Position And Trends Of The Intertropical Convergence Zone (Itcz) And Its Relationship With Upwelling In The Southern Caribbean Sea And Global Climate Indices, Kaitlyn E. Colna

USF Tampa Graduate Theses and Dissertations

The Intertropical Convergence Zone (ITCZ) is a feature that results from the ocean-atmosphere interactions in the tropics around the world. The ITCZ is characterized by surface wind convergence, tall storm clouds, and it forms a belt of high time-averaged precipitation around the globe. The ITCZ undergoes seasonal migrations between 5°S and 15°N roughly following the subsolar point on Earth with the seasons, with a mean annual position located slightly above the Equator, between 2° and 5°N.

This study tested the hypothesis that there was a northward shift in the median position of the ITCZ in the first decade of the …

Reduction Of Airborne Silica Concentration Using A Novel Sand Coating Technology, Elizabeth Rains Lloyd

USF Tampa Graduate Theses and Dissertations

The health effects of silica and the connection to occupational exposure has been known for years. In March of 2016, the Occupational Safety and Health Administration (OSHA) of the Department of Labor (DOL) published a new standard meant to reduce workers’ exposure to silica. The standard update was set forth to further protect workers; OSHA estimates this revision will prevent more than 600 silica-related deaths each year.

A key feature of the updated OSHA standard emphasizes the use of engineering controls and work practices in certain industries. Material handling of industrial sand is a known cause of silica overexposure in …

Playing-With The World: Toy Story's Aesthetics And Metaphysics Of Play, Jonathan Hendricks

USF Tampa Graduate Theses and Dissertations

Pixar’s Toy Story (John Lassiter, 1995) is not just a story about toys and the children that play with them, but a demonstration of how we interact with the world. This thesis looks at the way in which both main children, Andy and Sid, interact with their toys and how this interaction is one that is structured by way of what Martin Heidegger calls “Enframing.” In this modality of playing, toys and other things and entities in the world, and the world itself, appear to the children as on-hand resources for use at any time and can be molded, as …

Zonation Pattern And Spatial Arrangement Of A Geukensia Granosissima Population In A Mixed Mangrove Forest Of Tampa Bay, Derrick Shane Hudson

USF Tampa Graduate Theses and Dissertations

Here I provide the first report on Geukensia granosissima patterns of abundance along a tidal gradient within a mixed mangrove stand located in Tampa Bay, Florida, USA. Specifically, I examined 1) the relationship between G. granosissima size and density with mangrove root type (e.g. prop root, pneumatophore), and of density within the intertidal zones; and 2) the possible role of predation in shaping the lower zonation patterns displayed. Transect surveys located along the lower and upper population limit boundaries were conducted every two months over a ten-month period. Variables measured include size distribution, density of mussels, above ground mangrove prop …