Matching Items (90)
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Description
Despite the safe and effective use of attenuated vaccines for over fifty years, measles virus (MV) remains an insidious threat to global health. Problematically, infants less than one year of age, who are the most prone to severe infection and death by measles, cannot be immunized using current MV vaccines.

Despite the safe and effective use of attenuated vaccines for over fifty years, measles virus (MV) remains an insidious threat to global health. Problematically, infants less than one year of age, who are the most prone to severe infection and death by measles, cannot be immunized using current MV vaccines. For this dissertation, I generated and performed preclinical evaluation of two novel MV vaccine candidates. Based on data from clinical trials that showed increasing the dosage of current MV vaccines improved antibody responses in six-month-old recipients, I hypothesized that increasing the relevant antigenic stimulus of a standard titer dose would allow safe and effective immunization at a younger age. I generated two modified MVs with increased expression of the hemagglutinin (H) protein, the most important viral antigen for inducing protective neutralizing immunity, in the background of a current vaccine-equivalent. One virus, MVvac2-H2, expressed higher levels of full-length H, resulting in a three-fold increase in H incorporation into virions, while the second, MVvac2-Hsol, expressed and secreted truncated, soluble H protein to its extracellular environment. The alteration to the virion envelope of MVvac2-H2 conferred upon that virus a measurable resistance to in vitro neutralization. In initial screening in adult mouse models of vaccination, both modified MVs proved more immunogenic than their parental strain in outbred mice, while MVvac2-H2 additionally proved more immunogenic in the gold standard MV-susceptible mouse model. Remarkably, MVvac2-H2 better induced protective immunity in the presence of low levels of artificially introduced passive immunity that mimic the passive maternal immunity that currently limits vaccination of young infants, and that strongly inhibited responses to the current vaccine-equivalent. Finally, I developed a more physiological infant-like mouse model for MV vaccine testing, in which MV-susceptible dams vaccinated with the current vaccine-equivalent transfer passive immunity to their pups. This model will allow additional preclinical evaluation of the performance of MVvac2-H2 in pups of immune dams. Altogether, in this dissertation I identify a promising candidate, MVvac2-H2, for a next generation measles vaccine.
ContributorsJulik, Emily (Author) / Reyes del Valle, Jorge (Thesis advisor) / Chang, Yung (Committee member) / Blattman, Joseph (Committee member) / Hogue, Brenda (Committee member) / Nickerson, Cheryl (Committee member) / Arizona State University (Publisher)
Created2016
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Description
This dissertation consists of three substantive chapters. The first substantive chapter investigates the premature harvesting problem in fisheries. Traditionally, yield-per-recruit analysis has been used to both assess and address the premature harvesting of fish stocks. However, the fact that fish size often affects the unit price suggests that this approach

This dissertation consists of three substantive chapters. The first substantive chapter investigates the premature harvesting problem in fisheries. Traditionally, yield-per-recruit analysis has been used to both assess and address the premature harvesting of fish stocks. However, the fact that fish size often affects the unit price suggests that this approach may be inadequate. In this chapter, I first synthesize the conventional yield-per-recruit analysis, and then extend this conventional approach by incorporating a size-price function for a revenue-per-recruit analysis. An optimal control approach is then used to derive a general bioeconomic solution for the optimal harvesting of a short-lived single cohort. This approach prevents economically premature harvesting and provides an "optimal economic yield". By comparing the yield- and revenue-per-recruit management strategies with the bioeconomic management strategy, I am able to test the economic efficiency of the conventional yield-per-recruit approach. This is illustrated with a numerical study. It shows that a bioeconomic strategy can significantly improve economic welfare compared with the yield-per-recruit strategy, particularly in the face of high natural mortality. Nevertheless, I find that harvesting on a revenue-per-recruit basis improves management policy and can generate a rent that is close to that from bioeconomic analysis, in particular when the natural mortality is relatively low.

The second substantive chapter explores the conservation potential of a whale permit market under bounded economic uncertainty. Pro- and anti-whaling stakeholders are concerned about a recently proposed, "cap and trade" system for managing the global harvest of whales. Supporters argue that such an approach represents a novel solution to the current gridlock in international whale management. In addition to ethical objections, opponents worry that uncertainty about demand for whale-based products and the environmental benefits of conservation may make it difficult to predict the outcome of a whale share market. In this study, I use population and economic data for minke whales to examine the potential ecological consequences of the establishment of a whale permit market in Norway under bounded but significant economic uncertainty. A bioeconomic model is developed to evaluate the influence of economic uncertainties associated with pro- and anti- whaling demands on long-run steady state whale population size, harvest, and potential allocation. The results indicate that these economic uncertainties, in particular on the conservation demand side, play an important role in determining the steady state ecological outcome of a whale share market. A key finding is that while a whale share market has the potential to yield a wide range of allocations between conservation and whaling interests - outcomes in which conservationists effectively "buy out" the whaling industry seem most likely.

The third substantive chapter examines the sea lice externality between farmed fisheries and wild fisheries. A central issue in the debate over the effect of fish farming on the wild fisheries is the nature of sea lice population dynamics and the wild juvenile mortality rate induced by sea lice infection. This study develops a bioeconomic model that integrates sea lice population dynamics, fish population dynamics, aquaculture and wild capture salmon fisheries in an optimal control framework. It provides a tool to investigate sea lice control policy from the standpoint both of private aquaculture producers and wild fishery managers by considering the sea lice infection externality between farmed and wild fisheries. Numerical results suggest that the state trajectory paths may be quite different under different management regimes, but approach the same steady state. Although the difference in economic benefits is not significant in the particular case considered due to the low value of the wild fishery, I investigate the possibility of levying a tax on aquaculture production for correcting the sea lice externality generated by fish farms.
ContributorsHuang, Biao (Author) / Abbott, Joshua K (Thesis advisor) / Perrings, Charles (Thesis advisor) / Gerber, Leah R. (Committee member) / Muneepeerakul, Rachata (Committee member) / Schoon, Michael (Committee member) / Arizona State University (Publisher)
Created2014
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Description

Trees serve as a natural umbrella to mitigate insolation absorbed by features of the urban environment, especially building structures and pavements. For a desert community, trees are a particularly valuable asset because they contribute to energy conservation efforts, improve home values, allow for cost savings, and promote enhanced health and

Trees serve as a natural umbrella to mitigate insolation absorbed by features of the urban environment, especially building structures and pavements. For a desert community, trees are a particularly valuable asset because they contribute to energy conservation efforts, improve home values, allow for cost savings, and promote enhanced health and well-being. The main obstacle in creating a sustainable urban community in a desert city with trees is the scarceness and cost of irrigation water. Thus, strategically located and arranged desert trees with the fewest tree numbers possible potentially translate into significant energy, water and long-term cost savings as well as conservation, economic, and health benefits. The objective of this dissertation is to achieve this research goal with integrated methods from both theoretical and empirical perspectives.

This dissertation includes three main parts. The first part proposes a spatial optimization method to optimize the tree locations with the objective to maximize shade coverage on building facades and open structures and minimize shade coverage on building rooftops in a 3-dimensional environment. Second, an outdoor urban physical scale model with field measurement is presented to understand the cooling and locational benefits of tree shade. The third part implements a microclimate numerical simulation model to analyze how the specific tree locations and arrangements influence outdoor microclimates and improve human thermal comfort. These three parts of the dissertation attempt to fill the research gap of how to strategically locate trees at the building to neighborhood scale, and quantifying the impact of such arrangements.

Results highlight the significance of arranging residential shade trees across different geographical scales. In both the building and neighborhood scales, research results recommend that trees should be arranged in the central part of the building south front yard. More cooling benefits are provided to the building structures and outdoor microclimates with a cluster tree arrangement without canopy overlap; however, if residents are interested in creating a better outdoor thermal environment, open space between trees is needed to enhance the wind environment for better human thermal comfort. Considering the rapid urbanization process, limited water resources supply, and the severe heat stress in the urban areas, judicious design and planning of trees is of increasing importance for improving the life quality and sustaining the urban environment.

ContributorsZhao, Qunshan (Author) / Wentz, Elizabeth (Thesis advisor) / Sailor, David (Committee member) / Wang, Zhi-Hua (Committee member) / Arizona State University (Publisher)
Created2017
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Description
Many Fic domain proteins, through catalyzing post translational modifications (PTM) of protein substrates, functionally contribute to bacterial pathogenesis and the regulation of bacterial growth. Furthermore, one form of Fic-mediated regulation is the Fic toxin-antitoxin system, whereby an antitoxin interacts with and inhibits the Fic toxin. This study sought to determine

Many Fic domain proteins, through catalyzing post translational modifications (PTM) of protein substrates, functionally contribute to bacterial pathogenesis and the regulation of bacterial growth. Furthermore, one form of Fic-mediated regulation is the Fic toxin-antitoxin system, whereby an antitoxin interacts with and inhibits the Fic toxin. This study sought to determine the functional importance of Mycobacterium tuberculosis Fic and its putative antitoxin protein, Rv3642c. Using M. tuberculosis H37Rv genetic deletion mutants, fic and Rv3642c were demonstrated to promote intracellular survival in human THP-1 macrophage-like cells. Unlike other Fic toxins, of Fic toxin-antitoxin systems, Fic did not inhibit bacterial growth in vitro in the absence of Rv3642c. Notably, Fic demonstrated in vitro AMPylation of a THP-1 cell extract protein as shown by immunodetection. Fic also exhibited auto-AMPylation activity. Interestingly, a mutation of the conserved histidine in the Fic domain motif, a residue previously shown to be critical for AMPylation, had no effect on Fic-mediated ATP hydrolysis or AMPylation activity. Rv3642c was demonstrated to form a complex with Fic when co-expressed in Escherichia coli, indicating a toxin-antitoxin interaction. Screening M. tuberculosis protein fractions and culture filtrate with α-Fic and α-Rv3642c rabbit antisera did not detect monomers of Fic or Rv3642c, thus the cellular localization of Fic and the Rv3642c-Fic complex remains unclear. The results of this study provide insight into the function of M. tuberculosis Fic, and suggest that Fic and Rv3642c are important for M. tuberculosis survival in the intracellular macrophage environment. Furthermore, these findings challenge the current dogma that Fic domain catalysis is dependent on the conserved histidine of the Fic motif.
ContributorsLaMarca, Ryan (Author) / Haydel, Shelley (Thesis advisor) / Lake, Douglas (Committee member) / Nickerson, Cheryl (Committee member) / Arizona State University (Publisher)
Created2017
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Description
Prior to the COVID-19 global pandemic, ecotourism represented the tourism industry’s fastest growing segment with projections estimating that ecotourism would become the world’s largest tourism type by 2030. While the tourism industry will need several years to rebound, if historic trends tell us anything, it is that ecotourism will continue

Prior to the COVID-19 global pandemic, ecotourism represented the tourism industry’s fastest growing segment with projections estimating that ecotourism would become the world’s largest tourism type by 2030. While the tourism industry will need several years to rebound, if historic trends tell us anything, it is that ecotourism will continue to represent a large portion of the overall industry and will continue to grow at a rate that outpaces all other tourism types. In theory, ecotourism promotes sustainable socioeconomic development while also minimizing negative environmental impacts. Unfortunately, research suggests that this is not always true, and many examples exist of ecotourism causing more harm than good. In order to combat these potential negative impacts, the ecotourism industry has become increasingly reliant on ecotourism certification programs to act as an assessment tool that identifies ecotourism’s best practitioners while minimizing false advertising present within the industry. Despite these beliefs in the efficacy of certification, there is a lack of empirical research to actually support certification as an effective assessment tool. Furthermore, little research has been conducted that assesses the impacts that certification itself has on ecotourism businesses (both certified and uncertified) and the local communities dependent on ecotourism.
My dissertation employs a mixed methods design and combines qualitative and quantitative research methods spanning multiple geographic scales to develop an understanding of certification programs as they exist today and to discern the impacts that certification itself may cause for all those either directly or indirectly involved in ecotourism. My findings ultimately suggest that certification reform is needed if certification programs are expected to be the assessment tool ecotourism experts claim them to be. Specifically, as certification exists presently, there is: no universal guideline or standard for existing certification programs to follow, a disconnect between the advertised benefits certification offers and the actual benefits received, and a lack of market penetration both amongst ecotourists and ecotourism businesses. Each of these must be addressed before certification can live up to its full potential. Furthermore, I found that certification may impact community socioeconomic dynamics, particularly by creating or exacerbating community wealth distribution.
ContributorsDavila, Ryan (Author) / Kinzig, Ann (Thesis advisor) / Perrings, Charles (Committee member) / Collins, James (Committee member) / Schoon, Michael (Committee member) / Buzinde, Christine (Committee member) / Arizona State University (Publisher)
Created2020
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Description
ABSTRACT

Domestic dogs have assisted humans for millennia. However, the extent to which these helpful behaviors are prosocially motivated remains unclear. To assess the propensity of pet dogs to spontaneously and actively rescue distressed humans, this study tested whether sixty pet dogs would release their seemingly trapped owners from a large

ABSTRACT

Domestic dogs have assisted humans for millennia. However, the extent to which these helpful behaviors are prosocially motivated remains unclear. To assess the propensity of pet dogs to spontaneously and actively rescue distressed humans, this study tested whether sixty pet dogs would release their seemingly trapped owners from a large box. To examine the causal mechanisms that shaped this behavior, the readiness of each dog to open the box was tested in three conditions: 1) the owner sat in the box and called for help (“Distress” test), 2) an experimenter placed high-value food rewards in the box (“Food” test), and 3) the owner sat in the box and calmly read aloud (“Reading” test).

Dogs were as likely to release their distressed owner as to retrieve treats from inside the box, indicating that rescuing an owner may be a highly rewarding action for dogs. After accounting for ability, dogs released the owner more often when the owner called for help than when the owner read aloud calmly. In addition, opening latencies decreased with test number in the Distress test but not the Reading test. Thus, rescuing the owner could not be attributed solely to social facilitation, stimulus enhancement, or social contact-seeking behavior.

Dogs displayed more stress behaviors in the Distress test than in the Reading test, and stress scores decreased with test number in the Reading test but not in the Distress test. This evidence of emotional contagion supports the hypothesis that rescuing the distressed owner was an empathetically-motivated prosocial behavior. Success in the Food task and previous (in-home) experience opening objects were both strong predictors of releasing the owner. Thus, prosocial behavior tests for dogs should control for physical ability and previous experience.
ContributorsVan Bourg, Joshua Lazar (Author) / Wynne, Clive D (Thesis advisor) / Gilby, Ian C (Committee member) / Aktipis, C. Athena (Committee member) / Arizona State University (Publisher)
Created2019
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Description
Understanding how microorganisms adapt and respond to the microgravity environment of spaceflight is important for the function and integrity of onboard life support systems, astronaut health and mission success. Microbial contamination of spacecraft Environmental Life Support Systems (ECLSS), including the potable water system, are well documented and have caused major

Understanding how microorganisms adapt and respond to the microgravity environment of spaceflight is important for the function and integrity of onboard life support systems, astronaut health and mission success. Microbial contamination of spacecraft Environmental Life Support Systems (ECLSS), including the potable water system, are well documented and have caused major disruption to spaceflight missions. The potable water system on the International Space Station (ISS) uses recycled wastewater purified by multiple processes so it is safe for astronaut consumption and personal hygiene. However, despite stringent antimicrobial treatments, multiple bacterial species and biofilms have been recovered from this potable water system. This finding raises concern for crew health risks, vehicle operations and ECLSS system integrity during exploration missions. These concerns are further heightened given that 1) potential pathogens have been isolated from the ISS potable water system, 2) the immune response of astronauts is blunted during spaceflight, 3) spaceflight induces unexpected alterations in microbial responses, including growth and biofilm formation, antimicrobial resistance, stress responses, and virulence, and 4) different microbial phenotypes are often observed between reductionistic pure cultures as compared to more complex multispecies co-cultures, the latter of which are more representative of natural environmental conditions. To advance the understanding of the impact of microgravity on microbial responses that could negatively impact spacecraft ECLSS systems and crew health, this study characterized a range of phenotypic profiles in both pure and co-cultures of bacterial isolates collected from the ISS potable water system between 2009 and 2014. Microbial responses profiled included population dynamics, resistance to silver, biofilm formation, and in vitro colonization of intestinal epithelial cells. Growth characteristics and antibiotic sensitivities for bacterial strains were evaluated to develop selective and/or differential media that allow for isolation of a pure culture from co-cultures, which was critical for the success of this study. Bacterial co-culture experiments were performed using dynamic Rotating Wall Vessel (RWV) bioreactors under spaceflight analogue (Low Shear Modeled Microgravity/LSMMG) and control conditions. These experiments indicated changes in fluid shear have minimal impact on strain recovery. The antimicrobial efficacy of silver on both sessile co-cultures, grown on 316L stainless steel coupons, and planktonic co-cultures showed that silver did not uniformly reduce the recovery of all strains; however, it had a stronger antimicrobial effect on biofilm cultures than planktonic cultures. The impact of silver on the ability of RWV cultured planktonic and biofilm bacterial co-cultures to colonize human intestinal epithelial cells showed that, those strains which were impacted by silver treatment, often increased adherence to the monolayer. Results from these studies provide insight into the dynamics of polymicrobial community interactions, biofilm formation and survival mechanisms of ISS potable water isolates, with potential application for future design of ECLSS systems for sustainable human space exploration.
ContributorsKing, Olivia G (Author) / Nickerson, Cheryl (Thesis advisor) / Barrila, Jennifer (Committee member) / Ott, C (Committee member) / Yang, Jiseon (Committee member) / Arizona State University (Publisher)
Created2019
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Description
Climate adaptation has not kept pace with climate impacts which has formed an adaptation gap. Increasingly insurance is viewed as a solution to close this gap. However, the efficacy and implications of using insurance in the climate adaptation space are not clear. Furthermore, past research has focused on specific actors

Climate adaptation has not kept pace with climate impacts which has formed an adaptation gap. Increasingly insurance is viewed as a solution to close this gap. However, the efficacy and implications of using insurance in the climate adaptation space are not clear. Furthermore, past research has focused on specific actors or processes, not on the interactions and interconnections between the actors and the processes. I take a complex adaptive systems approach to map out how these dynamics are shaping adaptation and to interrogate what the insurance climate adaptation literature claims are the successes and pitfalls of insurance driving, enabling or being adaptation. From this interrogation it becomes apparent that insurance has enormous influence on its policy holders, builds telecoupling into local adaptation, and creates structures which support contradictory land use policies at the local level. Based on the influence insurance has on policy holders, I argue that insurance should be viewed as a form of governance. I synthesize insurance, governance and adaptation literature to examine exactly what governance tools insurance uses to exercise this influence and what the consequences may be. This research reveals that insurance may not be the exemplary adaptation approach the international community is hoping for. Using insurance, risk can be reduced without reducing vulnerability, and risk transfer can result in risk displacement which can reduce adaptation incentives, fuel maladaptation, or impose public burdens. Moreover, insurance requires certain information and legal relationships which can and often do structure that which is insured to the needs of insurance and shift authority away from governments to insurance companies or public-private partnerships. Each of these undermine the legitimacy of insurance-led local adaptation and contradict the stated social justice goals of international calls for insurance. Finally, I interrogate the potential justice concerns that emerged through an analysis of insurance as a form of adaptation governance. Using a multi-valent approach to justice I examine a suite of programs intended to support agricultural adaptation through insurance. This analysis demonstrates that although some programs clearly attempted to consider issues of justice, overall these existing programs raise distributional, procedural and recognition justice concerns.
ContributorsLueck, Vanessa (Author) / Klinsky, Sonja (Thesis advisor) / Schoon, Michael (Thesis advisor) / Eakin, Hallie (Committee member) / Arizona State University (Publisher)
Created2020
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Description
Institutions (rules, norms, and shared strategies) are social feedback systems that structure actors’ decision-making context. It is important to investigate institutional design to understand how rules interact and generate feedbacks that affect robustness, i.e., the ability to respond to change. This is particularly important when assessing sustainable use/conservation trade-offs that

Institutions (rules, norms, and shared strategies) are social feedback systems that structure actors’ decision-making context. It is important to investigate institutional design to understand how rules interact and generate feedbacks that affect robustness, i.e., the ability to respond to change. This is particularly important when assessing sustainable use/conservation trade-offs that affect species’ long-term survival. My research utilized the institutional grammar (IG) and robust institutional design to investigate these linkages in the context of four international conservation treaties.

First, the IG was used to code the regulatory formal treaty rules. The coded statements were then assessed to determine the rule linkages and dynamic interactions with a focus on monitoring and related reporting and enforcement mechanisms. Treaties with a regulatory structure included a greater number and more tightly linked rules related to these mechanisms than less regulatory instruments. A higher number of actors involved in these activities at multiple levels also seemed critical to a well-functioning monitoring system.

Then, drawing on existing research, I built a set of constitutive rule typologies to supplement the IG and code the treaties’ constitutive rules. I determined the level of fit between the constitutive and regulatory rules by examining the monitoring mechanisms, as well as treaty opt-out processes. Treaties that relied on constitutive rules to guide actor decision-making generally exhibited gaps and poorer rule fit. Regimes which used constitutive rules to provide actors with information related to the aims, values, and context under which regulatory rules were being advanced tended to exhibit better fit, rule consistency, and completeness.

The information generated in the prior studies, as well as expert interviews, and the analytical frameworks of Ostrom’s design principles, fit, and polycentricity, then aided the analysis of treaty robustness. While all four treaties were polycentric, regulatory regimes exhibited strong information processing feedbacks as evidenced by the presence of all design principles (in form and as perceived by experts) making them theoretically more robust to change than non-regulatory ones. Interestingly, treaties with contested decision-making seemed more robust to change indicating contestation facilitates robust decision-making or its effects are ameliorated by rule design.
ContributorsBrady, Ute (Author) / Anderies, John M. (Thesis advisor) / Schoon, Michael (Committee member) / Minteer, Ben A. (Committee member) / Gerber, Leah (Committee member) / Siddiki, Saba (Committee member) / Arizona State University (Publisher)
Created2020
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Description
This dissertation focuses on water security in terms of sustaining socio-economic development, livelihoods, and human well-being. Using the double exposure framework, I analyze the combined effect of climate change and economic development on water security in the Philippines. There is a need to examine how the combination of these two

This dissertation focuses on water security in terms of sustaining socio-economic development, livelihoods, and human well-being. Using the double exposure framework, I analyze the combined effect of climate change and economic development on water security in the Philippines. There is a need to examine how the combination of these two processes aggravate existing inequalities related to water security among different groups of people, and also analyze how these two processes can combine to increase stakeholders’ vulnerability to water-related shocks and stresses. The Philippines has been rated as one of the countries that is most vulnerable to climate change due to its exposure to extreme climate events and sea level rise. At the same time, the Philippines is currently undergoing an economic transition from a predominantly agricultural country to one where industry and services play a larger role. This dissertation zeroes in on the water security of municipalities in the Philippines, which were sorted into different syndromes based on a combination of their risk to future hydro-climatic changes and economic growth trends. Four syndromes which covered 73% of the population then emerged. By comparing five case study municipalities drawn from these four syndromes, I offer insights into how different combinations of climatic and economic factors can impact water security, and which combination could have the lowest water security in the future. Through analyzing the results of focus group discussions and semi-structured interviews, I also explore the variation of perceptions and collaborative strategies of stakeholders regarding their current and future water security. While each municipality had different climate and economic vulnerabilities, they shared largely similar water security perceptions and used the same strategies.
ContributorsLorenzo, Theresa Marie (Author) / Kinzig, Ann (Thesis advisor) / David, Carlos Primo (Committee member) / Perrings, Charles (Committee member) / Schoon, Michael (Committee member) / Selin, Cynthia (Committee member) / Arizona State University (Publisher)
Created2021