Matching Items (12,992)
Filtering by
- Creators: Arizona State University
Description
Contaminated aerosols and micro droplets are easily generated by infected hosts through sneezing, coughing, speaking and breathing1-3 and harm humans’ health and the global economy. While most of the efforts are usually targeted towards protecting individuals from getting infected,4 eliminating transmissions from infection sources is also important to prevent disease transmission. Supportive therapies for Severe Acute Respiratory Syndrome Coronavirus 2 (SARS CoV-2) pneumonia such as oxygen supplementation, nebulizers and non-invasive mechanical ventilation all carry an increased risk for viral transmission via aerosol to healthcare workers.5-9 In this work, I study the efficacy of five methods for self-containing aerosols emitted from infected subjects undergoing nebulization therapies with a diverse spectrum on Non-Invasive Positive Pressure Ventilator (NIPPV) with oxygen delivery therapies. The work includes five study cases: Case I: Use of a Full-Face Mask with biofilter in bilevel positive airway pressure device (BiPAP) therapy, Case II: Use of surgical mask in High Flow Nasal Cannula (HFNC) therapy, Case III: Use of a modified silicone disposable mask in a HFNC therapy, Case IV: Use of a modified silicone disposable mask with a regular nebulizer and normal breathing, Case V: Use of a mitigation box with biofilter in a BiPAP. We demonstrate that while cases I, III and IV showed efficacies of 98-100%; cases II and V, which are the most commonly used, resulted with significantly lower efficacies of 10-24% to mitigate the dispersion of nebulization aerosols. Therefore, implementing cases I, III and IV in health care facilities may help battle the contaminations and infections via aerosol transmission during a pandemic.
ContributorsShyamala Pandian, Adithya (Author) / Forzani, Erica (Thesis advisor) / Patel, Bhavesh (Committee member) / Xian, Xiaojun (Committee member) / Arizona State University (Publisher)
Created2021
Description
The presence of children can influence importantly how households respond to income risk. The aim of this dissertation is to study how different aspects of families' life-cycle decisions are affected by different sources of income fluctuation. In the first part of this dissertation, I study the relationships between fertility choices, consumption, and labor supply, by developing a model with endogenous fertility decisions and income volatility. Within this framework, fertility choices act as a mechanism to smooth utility over time. In this context, I analyze the insurance value of fertility choices. I use a structural model that combines two features underexplored by the literature: children as consumption commitments, and nonseparabilities of family size and consumption. Having children in the household affects consumption and labor marginal utilities, changing the insurance value of fertility decisions and generating incentives to avoid childbearing during low-income spells. I find that the welfare loss of a negative transitory income shock is 34 to 38 times larger if households are not able to choose when to have their children. These results underscore how costly unplanned childbearing can be to the household in terms of welfare.The second part of this dissertation evaluates the impact of being born under negative conditions in the labor market on human capital formation, and what parental behavior could be leading to those effects. I estimate the impact of the unemployment rates on children's assessment outcomes in cognitive and noncognitive skills. Counterintuitively, the results suggest that higher unemployment rates are linked to positive child development outcomes later in childhood. In my main specification, an increase of 1 percentage point in state unemployment causes an increase of 2.5% of a standard deviation in cognitive test scores after controlling for income at birth, hours worked at birth, and other variables.
ContributorsMangini, Marco (Author) / Silverman, Daniel (Thesis advisor) / Aucejo, Esteban (Committee member) / Murphy, Alvin (Committee member) / Arizona State University (Publisher)
Created2021
Description
Given the severity of risks that accompany the current COVID-19 pandemic, many are experiencing negative psychological effects, such as increased symptoms of depression and anxiety (i.e., mental health distress). As the COVID-19 pandemic continues to impress upon society, it is pertinent to assess the ways in which COVID-19 may be impacting first responders; many of which who are responsible for tending to the safety and wellbeing of communities during this time. However, little is known about how medical first responders may be experiencing COVID-19 related stress, whether this impacts their experience with symptoms of mental health distress, and furthermore whether this stress is different for those in different countries. As such, the present study sought to assess the association between COVID-19 related stress and symptoms of mental health distress in medical first responders for those living in Australia and the United States. Further, given the positive effects romantic relationships have on an individual’s interpersonal functioning, the potential moderating effect of perceived relationship commitment was examined. A total number of 79 participants completed the study. Contrary to hypotheses, results showed that there was no significant association between COVID-19 related stress and symptoms of distress, nor was relationship commitment found to moderate symptoms of distress. Implications of this study have the potential to guide mental health professionals working with medical first responders who are experiencing symptoms of distress, particularly in times of crises similar to that of COVID-19.
ContributorsEvers, Jessie Marie (Author) / Randall, Ashley K. (Thesis advisor) / Pereira, Jennifer (Committee member) / Warner, Cheryl (Committee member) / Arizona State University (Publisher)
Created2021
Description
Online learning in higher education has been increasing over the last two decades (NCES, 2016). Previous research has highlighted the importance of student engagement for academic achievement and performance (Fuller, Wilson, & Tobin, 2011; Northey et al., 2018). The current study aims to further understand students’ perceptions of peer interactions, assess the application of the Theory of Involvement in online learning environments, and identify factors of student engagement. Data were collected from 1,514 undergraduate students enrolled in online courses at Arizona State University (Mage = 25.96 years old; SD = 7.64; 1,259 female, 232 male, 12 non-binary, and 1 gender fluid). The results of this dissertation study indicate that the vast majority of students (94% of the sample) want opportunities for peer interaction in their online courses. Confirmatory Factor Analyses were conducted to validate three of the primary measures and these measurement models were used in subsequent analyses. Structural Equation Modeling (SEM) revealed that students who demonstrated high levels of Academic, Online Community, Life Application, and Social Engagement were more likely to perform well on measures of Academic Performance (i.e., doing well on quizzes or tests, earning higher letter grades). Additional SEM analyses indicated that sense of a community was related to all four aspects of student engagements. There was evidence that certain pedagogical factors were also associated with higher rates of student engagement. For example, students who reported high levels for Instructional Design (e.g., felt the course objectives were clear) were more likely to be academically engaged (i.e., demonstrated strong study habits). Lastly, while there were no significant differences in student engagement by gender, ethnicity, or living arrangements, students who valued peer interaction were more likely to report higher levels of Online Student Engagement. The findings of this research emphasize the desire online students have to interact with their peers, demonstrates the importance of engaging online students, and serves as a guide for educators in creating online courses that foster student engagement.
ContributorsCortes, Khaerannisa (Author) / Ladd, Becky (Thesis advisor) / Ladd, Gary (Committee member) / Thompson, Marilyn (Committee member) / Updegraff, Kimberly (Committee member) / Arizona State University (Publisher)
Created2021
Description
In combinatorial mathematics, a Steiner system is a type of block design. A Steiner triple system is a special case of Steiner system where all blocks contain 3 elements and each pair of points occurs in exactly one block. Independent sets in Steiner triple systems is the topic which is discussed in this thesis. Some properties related to independent sets in Steiner triple system are provided. The distribution of sizes of maximum independent sets of Steiner triple systems of specific order is also discussed in this thesis. An algorithm for constructing a Steiner triple system with maximum independent set whose size is restricted with a lower bound is provided. An alternative way to construct a Steiner triple system using an affine plane is also presented. A modified greedy algorithm for finding a maximal independent set in a Steiner triple system and a post-optimization method for improving the results yielded by this algorithm are established.
ContributorsWang, Zhaomeng (Author) / Colbourn, Charles (Thesis advisor) / Richa, Andrea (Committee member) / Jiang, Zilin (Committee member) / Arizona State University (Publisher)
Created2021
Description
Federal, state, and local entities prioritized addressing these academic deficiencies over the past several decades. An area of concern for teachers and families is multiplication. The two main purposes of this study are to (1) to determine how multiplication achievement and strategy use change from beginning to end of Bilingual Family Math Club, and (2) determine which of the eight components of Bilingual Family Math Club (BFMC) contribute to student learning outcomes. The components of BFMC are (1) Concrete Representational Abstract (CRA) modeling, (2) explicit vocabulary instruction, (3) word problems, (4) homework, (5) math games, (6) adult/child pairs as family engagement, (7) bilingual instruction, and (8) workshop series. Quantitative data includes pre-and post-intervention student math assessments. Qualitative data includes analysis of the scratch work artifacts students produced solving those assessments, as well as post-intervention from adults and students enrolled in the club. Findings from this study support previous research. Families said six of the components of the club helped them the most: adult-child pairs, series workshops, games during class, the CRA method, homework as games, and having a bilingual club. Two of the eight BFMC components families felt did not support them in learning multiplication were word problems and explicit vocabulary instruction. Quantitative results from a paired sample t-test showed a statistically significant change and large effect sizes in post-assessment scores in all four areas of the assessment: fluency, word problems, single-digit facts, and multi-digit multiplication. This study provided critical information for school leaders and district personnel attempting to implement more effective after school support programs for families in mathematics.
ContributorsSchroeder, Brittany (Author) / Basile, Carole (Thesis advisor) / Bernstein, Katherine (Committee member) / Ross, Lydia (Committee member) / Arizona State University (Publisher)
Created2021
Description
This dissertation consists of two essays related to dynamic debt contracting and financial economics. The first chapter studies key determinants of inclusion of a financial covenant in corporate loans from theoretical and empirical angles. Using a novel manually collected loan dataset of small to medium-sized publicly-listed U.S. firms, I find that firms that issue loans without financial covenants tend to have (i) lower accounting quality, (ii) lower assets, and (iii) are experiencing faster growth in profitability relative to firms that issue loans with financial covenants. I build a theoretical model of project financing in which there is noisy public information about the project’s profitability, and the lender can privately monitor to improve the information quality. I show that if the signal precision without monitoring is sufficiently low (high), the equilibrium contract does not include (includes) a covenant. Covenant inclusion plays a key role in providing incentives to the lender to monitor. I show that the lender monitors less often relative to the first best. Insufficient monitoring leads to “excessive risk-taking,” namely, bad quality firms continuing with the project too often. Relatedly, I also show that covenants are used less often in equilibrium relative to the first best. The second chapter examines equilibrium consequences of litigation by holdout creditors in sovereign debt renegotiation. I show that given a sufficiently high probability of winning the litigation case against the borrowing country and/or a high enough defaulted sovereign debt, the presence of the holdout creditors increases the expected debt recovery rate, which makes the default option less attractive, and decreases the country’s default probability and the interest rate on the country’s debt. The country responds by borrowing more but defaults less often along the equilibrium path as it wants to avoid default and facing holdout creditors. Having a non-zero probability of successful litigation is welfare improving for the country as it sustains higher debt and defaults less frequently.
ContributorsKim, Yong (Author) / Kovrijnykh, Natalia (Thesis advisor) / Mehra, Rajnish (Committee member) / Tserlukevich, Yuri (Committee member) / Arizona State University (Publisher)
Created2021
Description
In videos that contain actions performed unintentionally, agents do not achieve their desired goals. In such videos, it is challenging for computer vision systems to understand high-level concepts such as goal-directed behavior. On the other hand, from a very early age, humans are able to understand the relation between an agent and their ultimate goal even if the action gets disrupted or unintentional effects occur. Inculcating this ability in artificially intelligent agents would make them better social learners by not just learning from their own mistakes, i.e, reinforcement learning, but also learning from other's mistakes. For example, this could greatly reduce the search space for artificially intelligent agents for finding the correct action sequence when trying to achieve a new goal, since they would be able to learn from others what not to do as well as how/when actions result in undesired outcomes.To validate this ability of deep learning models to perform this task, the Weakly Augmented Oops (W-Oops) dataset is proposed, built upon the Oops dataset. W-Oops consists of 2,100 unintentional human action videos, with 44 goal-directed and 33 unintentional video-level activity labels collected through human annotations.
Inspired by previous methods on tasks such as weakly supervised action localization which show promise for achieving good localization results without ground truth segment annotations, this paper proposes a weakly supervised algorithm for localizing the goal-directed as well as the unintentional temporal region of a video using only video-level labels. In particular, an attention mechanism based strategy is employed that predicts the temporal regions which contributes the most to a classification task, leveraging solely video-level labels. Meanwhile, our designed overlap regularization allows the model to focus on distinct portions of the video for inferring the goal-directed and unintentional activity, while guaranteeing their temporal ordering. Extensive quantitative experiments verify the validity of our localization method.
ContributorsChakravarthy, Arnav (Author) / Yang, Yezhou (Thesis advisor) / Davulcu, Hasan (Committee member) / Pavlic, Theodore (Committee member) / Arizona State University (Publisher)
Created2021
Description
Much of the anthropological and Islamic studies focus in recent years has addressed the shifting forms of Islamic piety across Muslim majority societies. The analysis of this shift in Islamic practice and belief has enveloped the changing sensibilities around technologies, social strata, democracy, law, and everyday life. In light of these transformations, after the fall of the Indonesian New Order in 1998, the performances of Islamic devotional songs (salawat) by Habib Syech bin Abdul Qadir Assegaf (Habib Syech) began bringing millions of people together across Indonesia, Malaysia, Taiwan, Hong Kong, Thailand, South Korea, Egypt, Saudi Arabia, and Yemen. Although salawat has typically been performed in remembrance of the birth of Prophet Muhammad (mawlid) in localized celebrations. The performances of salawat by Habib Syech, on the other hand, occur fifteen or more times a month with crowds swelling to tens of thousands across multiple nation-states. Habib Syech’s salawat performances furthermore appeal to and bring together diverse Muslim populations that have historically been more divided. Habib Syech’s gatherings reveal how popular forms of piety are shifting in conjunction with profound societal changes in Indonesia and other Muslim communities. In untangling the popularity of Habib Syech’s gatherings, it was not until I became entangled in the rhythm of salawat that baraka, often translated as blessings, emerged as a slippery, elusive, and living helping propel the popularity of this phenomena. The guttural cries of my interlocutors (baraka, baraka, baraka) resonate and summon a methodology that takes the visible and invisible together in understanding the concept and life of baraka. I, like my interlocutors, began hunting baraka as an alternative, living concept that challenges understandings of Islam in Indonesia driven by Islamic civil organizations, prescriptive vs everyday Islamic piety, and Western interpretations of the world as disenchanted. This dissertation is an exploration of new opportunities for understanding religion in the modern world that emerge from the ethnographic field through the life of baraka.
ContributorsEdmonds, James Michael (Author) / Talebi, Shahla (Thesis advisor) / Bennett, Gaymon (Committee member) / Haines, Charles (Committee member) / Rush, James (Committee member) / Arizona State University (Publisher)
Created2021
Description
In the U.S, Middle Eastern (M.E) students often struggle with negative biases toward them and experience isolation, discrimination, and report a lack of meaningful interactions with U.S. students. Against this backdrop, this dissertation explored the impact of enacted similarity and nonverbal immediacy on social attraction and friendship-potential between same-sex U.S. and M.E. international students during first time interactions on Zoom. A 2 (M.E. vs. U.S. confederate) x 2 (low vs. high similarity) x 2 (low vs. high nonverbal immediacy) x 2 (pre- vs. post-interaction) experimental design was employed, with participants reporting on their perceptions after viewing a profile of a confederate and then again after they interacted with the confederate on Zoom for three minutes. Pre-interaction results indicated that M.E. women were perceived as the most socially attractive, highest friendship potential, and as most likely to engage in pleasant interaction, compared to the other three groups. This finding emerged even though U.S. women rated fellow U.S. women as more similar to them than they rated M.E. women. A potential explanation is intersectionality of gender and ethnicity, with U.S. women stereotyping M.E. women as quiet, submissive, and oppressed, and therefore have sympathy for them and expect them to be kind.
Post-interaction results revealed that in interactions between U.S. students, similarity impacted friendship potential but not social attraction, while nonverbal immediacy had a significant impact on both. In intercultural interactions between the U.S. and M.E. students, both nonverbal immediacy and similarity impacted social attraction and friendship potential. There were especially sharp drops in social attraction and friendship potential when the confederates enacted low levels of nonverbal immediacy. Overall, nonverbal immediacy had stronger and more consistent effects compared to similarity. Results indicate that to make positive impressions, both U.S. and M.E. students should use nonverbal immediacy cues such as smiling, leaning in, and being attentive to their interactional partner rather than looking away. Future directions include determining if findings can be generalized to face-to-face interactions and to perceptions of individuals from various cultures.
ContributorsLu, Anna Hommadova (Author) / Guerrero, Laura K (Thesis advisor) / Martin, Judith N (Thesis advisor) / Carradini, Stephen (Committee member) / Arizona State University (Publisher)
Created2021