Matching Items (195)
Description
Mathematical epidemiology, one of the oldest and richest areas in mathematical biology, has significantly enhanced our understanding of how pathogens emerge, evolve, and spread. Classical epidemiological models, the standard for predicting and managing the spread of infectious disease, assume that contacts between susceptible and infectious individuals depend on their relative frequency in the population. The behavioral factors that underpin contact rates are not generally addressed. There is, however, an emerging a class of models that addresses the feedbacks between infectious disease dynamics and the behavioral decisions driving host contact. Referred to as “economic epidemiology” or “epidemiological economics,” the approach explores the determinants of decisions about the number and type of contacts made by individuals, using insights and methods from economics. We show how the approach has the potential both to improve predictions of the course of infectious disease, and to support development of novel approaches to infectious disease management.
ContributorsPerrings, Charles (Author) / Castillo-Chavez, Carlos (Author) / Chowell-Puente, Gerardo (Author) / Daszak, Peter (Author) / Fenichel, Eli P. (Author) / Finnoff, David (Author) / Horan, Richard D. (Author) / Kilpatrick, A. Marm (Author) / Kinzig, Ann (Author) / Kuminoff, Nicolai (Author) / Levin, Simon (Author) / Morin, Benjamin (Author) / Smith, Katherine F. (Author) / Springborn, Michael (Author) / Simon M. Levin Mathematical, Computational and Modeling Sciences Center (Contributor) / College of Liberal Arts and Sciences (Contributor) / School of Life Sciences (Contributor) / School of Human Evolution and Social Change (Contributor) / W.P. Carey School of Business (Contributor) / Economics (Contributor) / Julie Ann Wrigley Global Institute of Sustainability (Contributor)
Created2015-12-01
Description
Background
Seroepidemiological studies before and after the epidemic wave of H1N1-2009 are useful for estimating population attack rates with a potential to validate early estimates of the reproduction number, R, in modeling studies.
Methodology/Principal Findings
Since the final epidemic size, the proportion of individuals in a population who become infected during an epidemic, is not the result of a binomial sampling process because infection events are not independent of each other, we propose the use of an asymptotic distribution of the final size to compute approximate 95% confidence intervals of the observed final size. This allows the comparison of the observed final sizes against predictions based on the modeling study (R = 1.15, 1.40 and 1.90), which also yields simple formulae for determining sample sizes for future seroepidemiological studies. We examine a total of eleven published seroepidemiological studies of H1N1-2009 that took place after observing the peak incidence in a number of countries. Observed seropositive proportions in six studies appear to be smaller than that predicted from R = 1.40; four of the six studies sampled serum less than one month after the reported peak incidence. The comparison of the observed final sizes against R = 1.15 and 1.90 reveals that all eleven studies appear not to be significantly deviating from the prediction with R = 1.15, but final sizes in nine studies indicate overestimation if the value R = 1.90 is used.
Conclusions
Sample sizes of published seroepidemiological studies were too small to assess the validity of model predictions except when R = 1.90 was used. We recommend the use of the proposed approach in determining the sample size of post-epidemic seroepidemiological studies, calculating the 95% confidence interval of observed final size, and conducting relevant hypothesis testing instead of the use of methods that rely on a binomial proportion.
Seroepidemiological studies before and after the epidemic wave of H1N1-2009 are useful for estimating population attack rates with a potential to validate early estimates of the reproduction number, R, in modeling studies.
Methodology/Principal Findings
Since the final epidemic size, the proportion of individuals in a population who become infected during an epidemic, is not the result of a binomial sampling process because infection events are not independent of each other, we propose the use of an asymptotic distribution of the final size to compute approximate 95% confidence intervals of the observed final size. This allows the comparison of the observed final sizes against predictions based on the modeling study (R = 1.15, 1.40 and 1.90), which also yields simple formulae for determining sample sizes for future seroepidemiological studies. We examine a total of eleven published seroepidemiological studies of H1N1-2009 that took place after observing the peak incidence in a number of countries. Observed seropositive proportions in six studies appear to be smaller than that predicted from R = 1.40; four of the six studies sampled serum less than one month after the reported peak incidence. The comparison of the observed final sizes against R = 1.15 and 1.90 reveals that all eleven studies appear not to be significantly deviating from the prediction with R = 1.15, but final sizes in nine studies indicate overestimation if the value R = 1.90 is used.
Conclusions
Sample sizes of published seroepidemiological studies were too small to assess the validity of model predictions except when R = 1.90 was used. We recommend the use of the proposed approach in determining the sample size of post-epidemic seroepidemiological studies, calculating the 95% confidence interval of observed final size, and conducting relevant hypothesis testing instead of the use of methods that rely on a binomial proportion.
ContributorsNishiura, Hiroshi (Author) / Chowell-Puente, Gerardo (Author) / Castillo-Chavez, Carlos (Author) / Simon M. Levin Mathematical, Computational and Modeling Sciences Center (Contributor) / College of Liberal Arts and Sciences (Contributor) / School of Human Evolution and Social Change (Contributor)
Created2011-03-24
Description
The purpose of this thesis is to compare ecolabeling to conservation easements for facilitating multi-use land between food production and conservation. Biodiversity has been on the decline as human agriculture uses more land. According to Encyclopedia Britannica “Half of the world’s habitable land (some 51 million square km [19.7 million square miles]) has been converted to agriculture, and some 77 percent of agricultural land (some 40 million square km [15.4 million square miles]) is used for grazing by cattle, sheep, goats, and other livestock. This massive conversion of forests, wetlands, grasslands, and other terrestrial ecosystems has produced a 60 percent decline (on average) in the number of vertebrates worldwide since 1970”(Rafferty 2010). The purpose of this paper is to explore ways individual landowners and private businesses can continue to operate profitably on their land while reversing the harmful loss to biodiversity observed in the past 50 years. Two of the most popular methods of achieving conservation on workable land are ecolabeling and conservation easements.
ContributorsWilcox, Christopher James (Author) / Leonard, Brian (Thesis director) / Schoon, Michael (Committee member) / Dean, W.P. Carey School of Business (Contributor) / Department of Supply Chain Management (Contributor) / Barrett, The Honors College (Contributor)
Created2020-12
Description
The issue of wild horse management in the American West has become prevalent in the media recently and management strategies are often criticized and opposed by the public. Horses have been a core feature of American history and culture nearly since the colonization of the western frontier, and popular media such as television and movies paint a romantic but often unrealistic picture of wild horses. Land management agencies must balance limited resources with an ever-growing wild horse population in order to properly manage public land so that it retains its ecological integrity and is still able to be used by multiple stakeholders, and they also must endure public criticism throughout the process. I used a photo elicitation survey to gather responses to photographic images of wild horses and determine how the public feels about wild horse management, given that horses are seen as a symbol of freedom and the American West. It was revealed that people who are unfamiliar with the issue still have opinions about how the horses should be managed, and these opinions often mirror what can be found in popular media.
ContributorsDuran, Kiana Alexis (Author) / Minteer, Ben (Thesis director) / Schoon, Michael (Thesis director) / Murphree, Julie (Committee member) / School of Life Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2019-05
Description
As human populations continue to expand, interactions with wildlife are expected to increase due to destruction of land and global climate change threatening native habitats. Established areas of protection are becoming essential to species survival and biodiversity protection. National Parks (NP) are a globally ubiquitous method employed to protect wildlife and habitats. Often NPs are mosaics of relatively small protected areas in a “sea” of human-dominated landscapes, and these remaining habitat “islands” are becoming essential to preventing species extinction. However, the establishment of a NP can lead to increased human-wildlife conflicts (HWC) and disenfranchisement of local communities, particularly along their borders. We conducted semi-structured interviews in six different countries to better understand the nature of HWCs at the borders of major NPs: (1) Khao Yai NP, Thailand; (2) Myall Lakes NP, Australia; (3) Chitwan NP, Nepal; (4) Kruger NP, South Africa; (5) Chingaza NP, Colombia, and (6) Yellowstone NP, United States. We evaluated affinity to wildlife, perception of conflicts, management success, and potential solutions at each park to better understand the global nature of HWCs.We also evaluated these data in relationship to the Human Development Index (HDI) to determine if there was a correlation between development and conflict issues. We found the intrinsic value of wildlife to not markedly differ between countries. Conflict was perceived as higher in the United States and Australia but was known to be of greater intensity in Nepal and South Africa. Management of NPs was well-regarded with a slight decrease from less-developed countries to more-developed countries, with solutions that were creative and unique to each region. Results appeared to be related to shifting baselines between countries and also to equivalency in a cross-cultural assessment. When these theories are taken into account, the complexity of HWCs globally is better understood. As our world continues to expand and NPs become some of the only contiguous native habitat and refuges for wildlife, it is important to understand the complex relationships occurring at the interface between natural and human communities and to explore effective solutions to these problems.
ContributorsRagan, Kinley Ann (Author) / Schoon, Michael (Thesis director) / Schipper, Jan (Committee member) / Senko, Jesse (Committee member) / School of Life Sciences (Contributor, Contributor) / School of Geographical Sciences and Urban Planning (Contributor) / Barrett, The Honors College (Contributor)
Created2019-05
Description
Human activities around the world are threatening scores of wildlife species, pushing them closer to extinction. In order to address what many conservationists view as a global biodiversity crisis, it is vital that more people are inspired to care about wild animals and motivated to act in ways that help protect them. The up-close experiences and personal connections that people form with wild animals in zoos accredited by the Association of Zoos and Aquariums (AZA) or the World Association of Zoos and Aquariums (WAZA) can help achieve this. However, it is not very well understood how different types of encounters within these zoos may inspire conservation mindedness and pro-environmental behaviors. During this thesis project, surveys were conducted at the AZA-accredited Arizona Center for Nature Conservation/Phoenix Zoo to understand how interactive, hands-on animal experiences within zoos differ from passively viewing zoo animals when it comes to inspiring people to care about conservation. The Phoenix Zoo is home to two different species of giraffes, and guests can view them from the front of the Savanna Exhibit. Guests can also participate in the Giraffe Encounter, which is a much more interactive, hands-on experience. After surveying guests at both locations, the results showed that fewer people at the Giraffe Encounter responded that they often engage in pro-environmental behaviors. This may indicate that the people who participated in the Giraffe Encounter came to the zoo more for recreation and entertainment than to learn about wildlife. Despite this, more people learned something new about nature or conservation at the Giraffe Encounter than they did at the Savanna Exhibit. On average, guests also felt that the Giraffe Encounter motivated them to learn more about how to help animals in the wild than the Savanna Exhibit did. Overall, there is a strong correlation between having an interactive, hands-on experience with a zoo animal and caring more about wildlife conservation. However, more research still needs to be done in order to conclusively provide evidence for causation.
ContributorsBurgess, Christa Noell (Author) / Schoon, Michael (Thesis director) / Minteer, Ben (Committee member) / Allard, Ruth (Committee member) / School of Life Sciences (Contributor) / School of Sustainability (Contributor, Contributor) / Barrett, The Honors College (Contributor)
Created2019-12
Description
This paper covers the wild horse overpopulation case study at the Salt River in Arizona, exploring how Traditional Ecological Knowledge (TEK) might help foster solutions to a lengthy and heated controversy about how to manage wild horses and burros on the rangeland. Fikret Berke's Sacred Ecology defines traditional ecological knowledge as, "a cumulative body of knowledge, practice, and belief evolving by adaptive processes and handed down through generations by cultural transmission, about the relationship of living beings (including humans) with one another and with their environment," (Berkes, 3). In contrast to current management strategies, TEK utilizes knowledge that comes from direct experience and intuitive knowing, rather than science-based, techno-rational streams of knowledge. Drawing on three modern sustainability concepts that support and stem from TEK, including: everything is connected, complex solutions can further complicate problems and diversity as a key to resilience, this paper sets forth a number of specific solutions to be considered moving forward, guided by the wisdom of TEK.
ContributorsLyford, Rebecca (Author) / Schoon, Michael (Thesis director) / Murphey, Julia (Committee member) / School of Sustainability (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05
Description
Circles of Sustainability is a self-evaluation tool designed to build educator capacity in K-12 schools seeking sustainability solutions. Based on the Sustainable Schools Challenge Handbook from Memphis, Tennessee, Circles of Sustainability considers environmental impact and efficiency, a healthy and safe school environment, sustainability and environmental education, and engagement and empowerment as four key pillars of whole-school sustainability. Each pillar is composed of elements and rubric items, which are reviewed, totaled, and colored in on the front page of the tool to help educators visualize and evaluate the current state of sustainability at their school. Since its first iteration completed in May 2017, the tool has been used by 300 educators throughout the United States during ASU's Sustainability Teachers' Academy (STA) workshops. Circles of Sustainability is completed as part of an activity called "Evaluating Your Community," where educators complete the tool and then brainstorm sustainability projects and solutions for their school and community. This paper is a review and discussion of the research, informal feedback and formal feedback used to create the second iteration of the tool. A second iteration of the tool was created to make the tool more user-friendly and ensure each pillar, element, and rubric item are based in research. The informal feedback was conducted during STA workshops in Tempe, Arizona; Abingdon, Virginia; Princeton, New Jersey; Chicago, Illinois; Los Angeles, California; Tucson, Arizona; and Charlotte, North Carolina. The formal feedback was conducted using a survey distributed to teachers who participated in the Tucson and Charlotte workshops. Overall, educators have responded positively to the tool, and the second iteration will continue to be used in future STA workshops throughout the United States.
ContributorsColbert, Julia (Author) / Schoon, Michael (Thesis director) / Merritt, Eileen (Committee member) / School of Sustainability (Contributor) / Division of Teacher Preparation (Contributor) / School of Geographical Sciences and Urban Planning (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05
Description
Fruit flies show a strong attraction to fruit odors. Most fruit odors, including strawberry scent, are complex multimolecular mixtures comprised of many chemically distinct constituents. How animals are able to process these mixtures and derive behaviorally relevant information is largely unknown. A new procedure was created to test odor preference for Heisenberg canton-s strain of Drosophila melanogaster. 30 flies were cold anesthetized at 4.2°C for 30 minutes and then placed in a testing arena. After acclimating for 45 minutes, the flies were exposed to two sources of air, one with ripe strawberry odor and one with only humidified air. Images were captured every minute for an hour and a preference index was calculated for every 10th image. The Drosophila had a positive average preference for the strawberry odor. Five out of six trials showed a general increase in odor preference over the course of the trial. While there was a generally positive trend for average preference over time, there was not a significant increase in average odor preference from time 1 to time 60. The data indicates that Drosophila show a preference for strawberry odor over humidified air, and we propose to extend this test to investigate how Drosophila process and react to complex odors and their chemical constituents.
ContributorsSteinmetz, Kyle J (Author) / Smith, Brian (Thesis director) / Jernigan, Chris (Committee member) / School of Life Sciences (Contributor, Contributor) / Barrett, The Honors College (Contributor)
Created2017-05
Description
Recent data suggests that olfactory input is important for antennal lobe development in honey bees. Chronic association of a single odor to food resources during crucial stages of development results in delayed antennal lobe development for mature foraging bees. The antennal lobes of these bees instead closely resemble an immature network observed in young, newly emerged bees. Using an odor stimuli variance assay, learning and memory tests can be used to explore how well honey bees discriminate single odors within complex odor mixtures. Here we are validating two different odor mixtures, a Brassica rapa floral blend and a second replicate mixture composed of common molecularly dissimilar odors. Odors in each mixture are either held constant or varied in concentration over 16 conditioning trials. Subsequent memory tests are performed two hours later to observe the ability of bees to distinguish and recognize specific odor components in each mixture. So far in our assay we find high rates of generalization for both odor mixtures. In general, more bees responded to all odors in the replicate treatment group over the Brassica treatment group. Additionally, bees in the Brassica treatment group did not respond to the target odor. More data is being collected to validate this assay. In future studies, I propose to apply this behavioral assay to bees with an altered olfactory developmental in order to see the functional impacts of this chronic odor association treatment.
ContributorsHalby, Rachael (Author) / Smith, Brian (Thesis director) / Jernigan, Christopher (Committee member) / School of Life Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2017-05