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Description
Diseases have been part of human life for generations and evolve within the population, sometimes dying out while other times becoming endemic or the cause of recurrent outbreaks. The long term influence of a disease stems from different dynamics within or between pathogen-host, that have been analyzed and studied by many researchers using mathematical models. Co-infection with different pathogens is common, yet little is known about how infection with one pathogen affects the host's immunological response to another. Moreover, no work has been found in the literature that considers the variability of the host immune health or that examines a disease at the population level and its corresponding interconnectedness with the host immune system. Knowing that the spread of the disease in the population starts at the individual level, this thesis explores how variability in immune system response within an endemic environment affects an individual's vulnerability, and how prone it is to co-infections. Immunology-based models of Malaria and Tuberculosis (TB) are constructed by extending and modifying existing mathematical models in the literature. The two are then combined to give a single nine-variable model of co-infection with Malaria and TB. Because these models are difficult to gain any insight analytically due to the large number of parameters, a phenomenological model of co-infection is proposed with subsystems corresponding to the individual immunology-based model of a single infection. Within this phenomenological model, the variability of the host immune health is also incorporated through three different pathogen response curves using nonlinear bounded Michaelis-Menten functions that describe the level or state of immune system (healthy, moderate and severely compromised). The immunology-based models of Malaria and TB give numerical results that agree with the biological observations. The Malaria--TB co-infection model gives reasonable results and these suggest that the order in which the two diseases are introduced have an impact on the behavior of both. The subsystems of the phenomenological models that correspond to a single infection (either of Malaria or TB) mimic much of the observed behavior of the immunology-based counterpart and can demonstrate different behavior depending on the chosen pathogen response curve. In addition, varying some of the parameters and initial conditions in the phenomenological model yields a range of topologically different mathematical behaviors, which suggests that this behavior may be able to be observed in the immunology-based models as well. The phenomenological models clearly replicate the qualitative behavior of primary and secondary infection as well as co-infection. The mathematical solutions of the models correspond to the fundamental states described by immunologists: virgin state, immune state and tolerance state. The phenomenological model of co-infection also demonstrates a range of parameter values and initial conditions in which the introduction of a second disease causes both diseases to grow without bound even though those same parameters and initial conditions did not yield unbounded growth in the corresponding subsystems. This results applies to all three states of the host immune system. In terms of the immunology-based system, this would suggest the following: there may be parameter values and initial conditions in which a person can clear Malaria or TB (separately) from their system but in which the presence of both can result in the person dying of one of the diseases. Finally, this thesis studies links between epidemiology (population level) and immunology in an effort to assess the impact of pathogen's spread within the population on the immune response of individuals. Models of Malaria and TB are proposed that incorporate the immune system of the host into a mathematical model of an epidemic at the population level.
ContributorsSoho, Edmé L (Author) / Wirkus, Stephen (Thesis advisor) / Castillo-Chavez, Carlos (Thesis advisor) / Chowell-Puente, Gerardo (Committee member) / Arizona State University (Publisher)
Created2011
Description
In the past decade, the use of mobile applications, specifically mobile applications focused on improving the health and fitness of users, has increased exponentially. As more consumers look towards mobile health applications to improve their health through dieting, exercise, and weight management, it is important to analyze how the concept of gamification can encourage sustained interaction and approval of these health-focused applications. This thesis aims to understand the prevalence of gamification amongst a large sample of health and fitness applications, identify and code the gamification features used in these apps, and finally, understand how different gamification features relate to the popularity and willingness to advocate using eWOM on behalf of a mobile app.
ContributorsBaugh, Monica (Author) / Dong, Xiaodan (Thesis director) / Montoya, Detra (Committee member) / Department of Marketing (Contributor) / Barrett, The Honors College (Contributor)
Created2021-05
Description
Solution methods for certain linear and nonlinear evolution equations are presented in this dissertation. Emphasis is placed mainly on the analytical treatment of nonautonomous differential equations, which are challenging to solve despite the existent numerical and symbolic computational software programs available. Ideas from the transformation theory are adopted allowing one to solve the problems under consideration from a non-traditional perspective. First, the Cauchy initial value problem is considered for a class of nonautonomous and inhomogeneous linear diffusion-type equation on the entire real line. Explicit transformations are used to reduce the equations under study to their corresponding standard forms emphasizing on natural relations with certain Riccati(and/or Ermakov)-type systems. These relations give solvability results for the Cauchy problem of the parabolic equation considered. The superposition principle allows to solve formally this problem from an unconventional point of view. An eigenfunction expansion approach is also considered for this general evolution equation. Examples considered to corroborate the efficacy of the proposed solution methods include the Fokker-Planck equation, the Black-Scholes model and the one-factor Gaussian Hull-White model. The results obtained in the first part are used to solve the Cauchy initial value problem for certain inhomogeneous Burgers-type equation. The connection between linear (the Diffusion-type) and nonlinear (Burgers-type) parabolic equations is stress in order to establish a strong commutative relation. Traveling wave solutions of a nonautonomous Burgers equation are also investigated. Finally, it is constructed explicitly the minimum-uncertainty squeezed states for quantum harmonic oscillators. They are derived by the action of corresponding maximal kinematical invariance group on the standard ground state solution. It is shown that the product of the variances attains the required minimum value only at the instances that one variance is a minimum and the other is a maximum, when the squeezing of one of the variances occurs. Such explicit construction is possible due to the relation between the diffusion-type equation studied in the first part and the time-dependent Schrodinger equation. A modication of the radiation field operators for squeezed photons in a perfect cavity is also suggested with the help of a nonstandard solution of Heisenberg's equation of motion.
ContributorsVega-Guzmán, José Manuel, 1982- (Author) / Sulov, Sergei K (Thesis advisor) / Castillo-Chavez, Carlos (Thesis advisor) / Platte, Rodrigo (Committee member) / Chowell-Puente, Gerardo (Committee member) / Arizona State University (Publisher)
Created2013
Description
Mortality of 1918 influenza virus was high, partly due to bacteria coinfections. We characterize pandemic mortality in Arizona, which had high prevalence of tuberculosis. We applied regressions to over 35,000 data points to estimate the basic reproduction number and excess mortality. Age-specific mortality curves show elevated mortality for all age groups, especially the young, and senior sparing effects. The low value for reproduction number indicates that transmissibility was moderately low.
ContributorsJenner, Melinda Eva (Author) / Chowell-Puente, Gerardo (Thesis director) / Kostelich, Eric (Committee member) / Barrett, The Honors College (Contributor) / School of Mathematical and Statistical Sciences (Contributor) / School of Life Sciences (Contributor)
Created2015-05
Description
Background: While research has quantified the mortality burden of the 1957 H2N2 influenza pandemic in the United States, little is known about how the virus spread locally in Arizona, an area where the dry climate was promoted as reducing respiratory illness transmission yet tuberculosis prevalence was high.
Methods: Using archival death certificates from 1954 to 1961, this study quantified the age-specific seasonal patterns, excess-mortality rates, and transmissibility patterns of the 1957 pandemic in Maricopa County, Arizona. By applying cyclical Serfling linear regression models to weekly mortality rates, the excess-mortality rates due to respiratory and all-causes were estimated for each age group during the pandemic period. The reproduction number was quantified from weekly data using a simple growth rate method and generation intervals of 3 and 4 days. Local newspaper articles from The Arizona Republic were analyzed from 1957-1958.
Results: Excess-mortality rates varied between waves, age groups, and causes of death, but overall remained low. From October 1959-June 1960, the most severe wave of the pandemic, the absolute excess-mortality rate based on respiratory deaths per 10,000 population was 17.85 in the elderly (≥65 years). All other age groups had extremely low excess-mortality and the typical U-shaped age-pattern was absent. However, relative risk was greatest (3.61) among children and young adolescents (5-14 years) from October 1957-March 1958, based on incidence rates of respiratory deaths. Transmissibility was greatest during the same 1957-1958 period, when the mean reproduction number was 1.08-1.11, assuming 3 or 4 day generation intervals and exponential or fixed distributions.
Conclusions: Maricopa County largely avoided pandemic influenza from 1957-1961. Understanding this historical pandemic and the absence of high excess-mortality rates and transmissibility in Maricopa County may help public health officials prepare for and mitigate future outbreaks of influenza.
Methods: Using archival death certificates from 1954 to 1961, this study quantified the age-specific seasonal patterns, excess-mortality rates, and transmissibility patterns of the 1957 pandemic in Maricopa County, Arizona. By applying cyclical Serfling linear regression models to weekly mortality rates, the excess-mortality rates due to respiratory and all-causes were estimated for each age group during the pandemic period. The reproduction number was quantified from weekly data using a simple growth rate method and generation intervals of 3 and 4 days. Local newspaper articles from The Arizona Republic were analyzed from 1957-1958.
Results: Excess-mortality rates varied between waves, age groups, and causes of death, but overall remained low. From October 1959-June 1960, the most severe wave of the pandemic, the absolute excess-mortality rate based on respiratory deaths per 10,000 population was 17.85 in the elderly (≥65 years). All other age groups had extremely low excess-mortality and the typical U-shaped age-pattern was absent. However, relative risk was greatest (3.61) among children and young adolescents (5-14 years) from October 1957-March 1958, based on incidence rates of respiratory deaths. Transmissibility was greatest during the same 1957-1958 period, when the mean reproduction number was 1.08-1.11, assuming 3 or 4 day generation intervals and exponential or fixed distributions.
Conclusions: Maricopa County largely avoided pandemic influenza from 1957-1961. Understanding this historical pandemic and the absence of high excess-mortality rates and transmissibility in Maricopa County may help public health officials prepare for and mitigate future outbreaks of influenza.
ContributorsCobos, April J (Author) / Jehn, Megan (Thesis director) / Chowell-Puente, Gerardo (Committee member) / Barrett, The Honors College (Contributor) / School of Human Evolution and Social Change (Contributor) / School of Life Sciences (Contributor)
Created2015-05
Description
Branding is one of the most important tools a business can use. Whether consumers know it or not, every purchasing decision that they make – be it for a product or service – is rooted in the brand. Thus, it is somewhat of a surprise that branding for individuals did not become popularized until 1997, with Tom Peters’ article “The Brand Called You.” In his article, Peters remarks on how changes in the marketplace and technology make developing a personal brand more accessible, as well as more important. The increasingly competitive marketplace combined with the rise of social media means that personal branding is even more important and more attainable today. Thus, it is vital for students entering the workforce to develop a brand that will allow them to distinguish themselves. This research examines whether or not students understand what personal branding is and if they have taken the steps to develop their personal brand. The research questions are as follows:
• Do students understand what personal branding is?
• Are students able to define their skills?
• Do students have a career plan?
• Do students have a plan to promote their brand?
A pilot study was first distributed to students of Arizona State University which found that students lack an understanding of what personal branding is and have a need for the knowledge and tools to develop a personal brand. A workshop was then developed to address these issues. This workshop was held three times: first, for a Landscape Architecture class, second, for a marketing class, and third, for a student sales organization. The workshop discussed branding, personal branding, and then the participants were able to begin working on developing their own personal brand. The students in the first workshop had two sessions and were able to complete their own personal brand process with the workshop leader, while participants from the second and third workshops completed it on their own, after only a single workshop session. After completing the in-person workshop, participants shared their brand with their fellow students in a Google Plus page. Finally, participants completed an exit survey. This exit survey was used to measure the research questions.
The first workshop proved to be most effective, even though the participants in the first workshop were all landscape design students and the majority of the participants in the second and third workshops were business students. It was found that unless the students’ own brand development process was finished during the workshop or affected the students’ grade, it would not be completed. It was also evident in all of the workshops that slides with imagery were more effective at starting discussions than the text-heavy slides. As such, future workshops should be designed with a greater time allowance, the intent of the students’ own brand development process to be completed during the workshop, and the presentation should be redesigned to better initiate discussion among participants.
• Do students understand what personal branding is?
• Are students able to define their skills?
• Do students have a career plan?
• Do students have a plan to promote their brand?
A pilot study was first distributed to students of Arizona State University which found that students lack an understanding of what personal branding is and have a need for the knowledge and tools to develop a personal brand. A workshop was then developed to address these issues. This workshop was held three times: first, for a Landscape Architecture class, second, for a marketing class, and third, for a student sales organization. The workshop discussed branding, personal branding, and then the participants were able to begin working on developing their own personal brand. The students in the first workshop had two sessions and were able to complete their own personal brand process with the workshop leader, while participants from the second and third workshops completed it on their own, after only a single workshop session. After completing the in-person workshop, participants shared their brand with their fellow students in a Google Plus page. Finally, participants completed an exit survey. This exit survey was used to measure the research questions.
The first workshop proved to be most effective, even though the participants in the first workshop were all landscape design students and the majority of the participants in the second and third workshops were business students. It was found that unless the students’ own brand development process was finished during the workshop or affected the students’ grade, it would not be completed. It was also evident in all of the workshops that slides with imagery were more effective at starting discussions than the text-heavy slides. As such, future workshops should be designed with a greater time allowance, the intent of the students’ own brand development process to be completed during the workshop, and the presentation should be redesigned to better initiate discussion among participants.
ContributorsBinsfeld, Jacqueline Rose (Author) / Montoya, Detra (Thesis director) / Gray, Nancy (Committee member) / Department of Marketing (Contributor) / W. P. Carey School of Business (Contributor) / Barrett, The Honors College (Contributor)
Created2015-12
Description
In today’s society we see a strong encouragement of those who put effort into various aspects of their life. Additionally, we also see a strong push towards making oneself more attractive to reap social benefits. However, a paradox exists between effort and attractiveness. In a society that values both effort and attractiveness, why do we see negative reactions to those who put effort into their appearance, and can we make these effects go away? How can cosmetic companies alter those reactions to suit their advertising needs? Through a pretest and a main study we show how consumers react to differing amounts of perceived effort in a cosmetic product, and how we can alter the effect that effort has by priming consumers with the idea of their ‘natural self’ vs. their ‘ideal’ self.
ContributorsDaniels, Michelle Elizabeth (Author) / Samper, Adriana (Thesis director) / Montoya, Detra (Committee member) / Barrett, The Honors College (Contributor) / Department of Supply Chain Management (Contributor) / Department of Marketing (Contributor)
Created2014-05
Description
An in-depth analysis of Homeview Realty and Homeview Financial was conducted. A marketing plan for both companies was prepared for this project. Homeview Realty and Homeview Financial are in the midst of dynamic industries. The landscape of doing business in the real estate and mortgage industries are constantly changing and evolving. Thus, it is vital for Homeview Realty and Homeview Financial to constantly be knowledgeable in these fields. With this dynamic aspect, the landscape for marketing has also changed; it became digital in nature. Thus, it is important to analyze Homeview Realty and Homeview Financial currently and create a live marketing plan that can be updated when needed. With a marketing plan in hand, Homeview will be able understand its business model, mission, goals, and objectives and in turn be able to create marketing campaigns compatible with the companies objectives and strategic directions.
ContributorsCrowley, Rachel Victoria (Author) / Ostrom, Lonnie (Thesis director) / Montoya, Detra (Committee member) / Mirshak, Paul (Committee member) / Barrett, The Honors College (Contributor) / Department of Marketing (Contributor) / Department of Supply Chain Management (Contributor) / Department of Chemistry and Biochemistry (Contributor) / Department of Finance (Contributor) / School of Accountancy (Contributor)
Created2014-05
Description
The aim of this thesis project was to conduct a brand analysis for a local juice company, Kaleidoscope Juice. Through this brand analysis, Kaleidoscope's current branding and marketing strategies were assessed as well as their narrow positioning strategy within the juicing industry. As such, the primary focus of the research and field work was Kaleidoscope's positioning, and how expanding their current target customer group would be advantageous for the brand both financially and operationally. Both primary and secondary sources were utilized to help identify key factors and pricing in the juicing industry as well as the competitive marketplace. Additionally, an online survey was created and approved by the IRB that was used to help understand consumer's perceptions of the industry, as well as the brand and brand elements. The questionnaire was distributed online, and a group of 91 participants were sampled for the purpose of the study. The results were extremely useful in understanding price sensitivity, as well as preferred distribution methods for consumers. Additionally, the data supported much of the research and field work conducted in the analysis and helped to solidify branding recommendations for Kaleidoscope. It was concluded that although Kaleidoscope does have a strong target customer base, expanding and educating a new target consumer would be extremely beneficial for the brand going into the future.
ContributorsTremel, Sarah Anne (Author) / Montoya, Detra (Thesis director) / Samper, Adriana (Committee member) / Barrett, The Honors College (Contributor) / Department of Supply Chain Management (Contributor) / Department of Marketing (Contributor)
Created2014-05
Description
C.C. Silver & Gold Inc., a local precious metals and coin dealer, is introducing a new product line, Tooth Fairy Tokens. This one year marketing plan aims to clearly define the business goals of this new venture by outlining the company's current market position and providing it with a competitive marketing strategy that relies on niche market opportunities and established supplier relationships. By providing the firm with a solid foundation of research and direction, this marketing plan will help the company achieve its goals of gaining a market presence and increasing company revenue within the first three years of introduction.
ContributorsBlackmer, Courtney Lauren (Author) / Montoya, Detra (Thesis director) / Ostrom, Amy (Committee member) / Brown, Steven (Committee member) / Barrett, The Honors College (Contributor) / Department of Supply Chain Management (Contributor) / Department of Marketing (Contributor) / W. P. Carey School of Business (Contributor)
Created2013-05