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- Genre: Masters Thesis
Description
Waveform design that allows for a wide variety of frequency-modulation (FM) has proven benefits. However, dictionary based optimization is limited and gradient search methods are often intractable. A new method is proposed using differential evolution to design waveforms with instantaneous frequencies (IFs) with cubic FM functions whose coefficients are constrained to the surface of the three dimensional unit sphere. Cubic IF functions subsume well-known IF functions such as linear, quadratic monomial, and cubic monomial IF functions. In addition, all nonlinear IF functions sufficiently approximated by a third order Taylor series over the unit time sequence can be represented in this space. Analog methods for generating polynomial IF waveforms are well established allowing for practical implementation in real world systems. By sufficiently constraining the search space to these waveforms of interest, alternative optimization methods such as differential evolution can be used to optimize tracking performance in a variety of radar environments. While simplified tracking models and finite waveform dictionaries have information theoretic results, continuous waveform design in high SNR, narrowband, cluttered environments is explored.
ContributorsPaul, Bryan (Author) / Papandreou-Suppappola, Antonia (Thesis advisor) / Bliss, Daniel W (Thesis advisor) / Tepedelenlioğlu, Cihan (Committee member) / Arizona State University (Publisher)
Created2014
Description
Teaching evolution has been shown to be a challenge for faculty, in both K-12 and postsecondary education. Many of these challenges stem from perceived conflicts not only between religion and evolution, but also faculty beliefs about religion, it's compatibility with evolutionary theory, and it's proper role in classroom curriculum. Studies suggest that if educators engage with students' religious beliefs and identity, this may help students have positive attitudes towards evolution. The aim of this study was to reveal attitudes and beliefs professors have about addressing religion and providing religious scientist role models to students when teaching evolution. 15 semi-structured interviews of tenured biology professors were conducted at a large Midwestern universiy regarding their beliefs, experiences, and strategies teaching evolution and particularly, their willingness to address religion in a class section on evolution. Following a qualitative analysis of transcripts, professors did not agree on whether or not it is their job to help students accept evolution (although the majority said it is not), nor did they agree on a definition of "acceptance of evolution". Professors are willing to engage in students' religious beliefs, if this would help their students accept evolution. Finally, professors perceived many challenges to engaging students' religious beliefs in a science classroom such as the appropriateness of the material for a science class, large class sizes, and time constraints. Given the results of this study, the author concludes that instructors must come to a consensus about their goals as biology educators as well as what "acceptance of evolution" means, before they can realistically apply the engagement of student's religious beliefs and identity as an educational strategy.
ContributorsBarnes, Maryann Elizabeth (Author) / Brownell, Sara E (Thesis advisor) / Brem, Sarah K. (Thesis advisor) / Lynch, John M. (Committee member) / Ellison, Karin (Committee member) / Arizona State University (Publisher)
Created2014
Description
Infectious disease presents a serious threat to our fitness. The biological immune system provides several mechanisms for dealing with this threat. So too does another system: the behavioral immune system. This second system is proposed to consist of a set of evolved cognitive, affective, and behavioral strategies for reducing the likelihood of infection, including xenophobia, traditionalism, and food neophobia. In the present work, I investigate how another suite of fairly novel culturally-learned disease avoidance strategies, namely hygiene behaviors and knowledge of germ theory, are related to the behavioral immune system. Across two studies, I find that individuals who engage in more hygiene behaviors show less evidence of reliance on several elements of the behavioral immune system (i.e., xenophobia, traditionalism, food neophobia). Similarly, individuals who know more about germ theory show less engagement in behavioral immune system components. These findings suggest that effective cultural strategies for avoiding infectious disease may supplant older, evolved psychological strategies with the same purpose.
ContributorsWormley, Alexandra S (Author) / Varnum, Michael E.W. (Thesis advisor) / Cohen, Adam B (Committee member) / Kenrick, Douglas (Committee member) / Arizona State University (Publisher)
Created2022
Description
This review aims to provide a comprehensive review of the most recent literature on adaptive therapy, a promising new approach to cancer treatment that leverages evolutionary theory to prolong tumor control1. By capitalizing on the competition between drug-sensitive and drug-resistant cells, adaptive therapy has led to a paradigm shift in oncology. Through mathematical and in silico models, researchers have examined key factors such as dose timing, cost of resistance, and spatial dynamics in tumor response to adaptive therapy. With a partial focus on preclinical experiments involving ovarian and breast cancer, this review will discuss the demonstrated effectiveness of adaptive therapy in improving progression free survival and tumor control. Through the review process, it was determined that dose modulation outperformed drug-vacation strategies, emphasizing the significance of tumor heterogeneity and spatial structure in accurately modeling adaptive therapy mechanisms. The potential of ongoing clinical trials to improve patient outcomes and long-term treatment efficacy is emphasized, while a thorough analysis of study methodologies shapes the future direction of adaptive therapy research.
ContributorsRichker, Harley (Author) / Maley, Carlo C (Thesis advisor) / Compton, Carolyn (Committee member) / Wilson, Melisaa (Committee member) / Arizona State University (Publisher)
Created2023
Description
A big part of understanding cancer is understanding the cellular environment itthrives in by analyzing it from a microecological perspective. Humans and other species
are affected by different cancer types, and this highlights the notion that there may be a
correlation between specific tissues and neoplasia prevalence. Research shows that
humans are the most susceptible to adenocarcinomas and carcinomas which include the
following tissues: lungs, breast, prostate, and pancreas. Furthermore, research shows that
adenocarcinoma accounts for 38.5% of all lung cancer cases, 20% of small cell
carcinomas, and 2.9% of large cell carcinoma. The incidence of the most common cancer
types in humans is consistently increasing annually. This study analyzes trends of tissue-specific cancers across species to examine possible contributors to vulnerability to
cancer. I predicted that adenocarcinomas would be the most prevalent cancer type across
the tree of life. To test this hypothesis, I reviewed over 130 species that reported equal to
or greater than 50 individual necropsy pathology records across 4 classes (Mammalia,
amphibia, Reptilia, Aves) and ranked them by neoplasia prevalence. This information was
then organized in tables in descending order. The study’s resulting tables and data
concluded that the hypothesis was correct. I found that across all species
adenocarcinomas were the most common cancer type and account for 30.4% of
malignancies reported among species. Future research should investigate how organ size
contributes to neoplasia prevalence.
ContributorsPERAZA, ASHLEY (Author) / Maley, Carlo (Thesis advisor) / Boddy, Amy (Thesis advisor) / Baciu, Cristina (Committee member) / Arizona State University (Publisher)
Created2022
Description
Resource transfers can confer many adaptive benefits such as specialization, helping genetically related individuals, future compensation, and risk-pooling. Need-based transfers are a risk-pooling mechanism in which partners mitigate unpredictable losses by transferring resources based on need. Need-based transfers are likely to be most useful for resources that are necessary and unpredictable because being unable to reliably obtain essential resources would be devastating. However, need-based transfers make people vulnerable to two types of exploitation: a person can be greedy by asking when not in need and a person with a surplus of resources can be stingy by not giving to someone in need. Previous research suggests that people might have cognitive mechanisms for detecting greediness and stinginess, which would serve to protect against exploitation by cheaters. This study investigated whether resources that are necessary and unpredictable are most likely to trigger greediness and stinginess detection mechanisms. Participants saw four types of rules. One rule could be violated through greedy behavior, another through stingy behavior, another by not paying a debt, and another was a descriptive rule that could be violated by not finding one type of resource near another type of resource. Then, participants saw information about events relating to one of the rules and indicated whether the rule in question could have been violated. Consistent with past research, participants were better at detecting greediness, stinginess, and debts not paid than at detecting violations of a descriptive rule. However, contrary to my predictions, the necessity and unpredictability of resources did not impact people’s ability to detect greediness and stinginess. The lack of support for my hypothesis might be because the benefits of detecting greediness and stinginess might outweigh the costs even for situations in which need-based transfer rules are unlikely to apply, because people might be able to consciously activate their greediness and stinginess mechanisms even for resources that would not naturally trigger them, or because of methodological limitations.
ContributorsMunoz Castro, Andres (Author) / Aktipis, Athena (Thesis advisor) / Hruschka, Daniel (Committee member) / Neuberg, Steven (Committee member) / Arizona State University (Publisher)
Created2019
Description
Regulation of transcription initiation is a critical factor in the emergence of diverse biological phenotypes, including the development of multiple cell types from a single genotype, the ability of organisms to respond to environmental cues, and the rise of heritable diseases. Transcription initiation is regulated in large part by promoter regions of DNA. The identification and characterization of cis-regulatory regions, and understanding how these sequences differ across species, is a question of interest in evolution. To address this topic, I used the model organism Daphnia pulex, a well-characterized microcrustacean with an annotated genome sequence and selected a distribution of well-defined populations geographically located throughout the Midwestern US, Oregon, and Canada. Using isolated total RNA from adult, female Daphnia originating from the selected populations as well as a related taxon, Daphnia pulicaria (200,000 years diverged from D. pulex), I identified an average of over 14,000 (n=14,471) promoter regions using a novel transcription start site (TSS) profiling method, STRIPE-seq. Through the identification of sequence architecture, promoter class, conservation, and transcription start region (TSR) width, of cis-regulatory regions across the aforementioned Daphnia populations, I constructed a system for the study of promoter evolution, enabling a robust interpretation of promoter evolution in the context of the population-genetic environment. The methodology presented, coupled with the generated dataset, provides a foundation for the study of the evolution of promoters across both species and populations.
ContributorsSnyder, Shannon (Author) / Lynch, Michael (Thesis advisor) / Harris, Robin (Committee member) / Raborn, Randolph T (Committee member) / Wideman, Jeremy (Committee member) / Arizona State University (Publisher)
Created2020