Digital Commons Network^™

Postsecondary Stem Paths Of High-Achieving Students In Math And Science: A Longitudinal Multilevel Investigation Of Their Selection And Persistence, Soohyun Yi

Open Access Dissertations

This study used a quantitative approach to investigate high-school students’ talent-development pathways in STEM from 10th through 12th grades and for 8 years thereafter. The purpose of this study was to longitudinally investigate three important choices and accomplishments on the STEM talent development trajectory: a) selecting a STEM major in college; b) persisting with the STEM major until graduation; and c) selecting a career in STEM after college graduation. Given that students with gifts and talents are more likely to persist and succeed in STEM fields than average achievers, and understanding their unique needs may be the first important task …

A Comprehensive Analysis Of Estimating Land Use Change Emissions Induced By Global Aviation Biofuels Production Using Economic Equilibrium Models, Xin Zhao

Open Access Dissertations

This dissertation is comprised of three independent but closely related essays, which provide new insights on estimating biofuels induced land use (ILUC) change and related emissions from distinct perspectives. The first essay in this dissertation developed the framework for estimating aviation biofuels induced land use change emissions using GTAP-BIO and its coupled emission model, AEZ-EF. We translate International Energy Agency (IEA) projections into appropriate shock sizes by region and pathway. We make modifications in GTAP-BIO to introduce the aviation biofuels pathways and update AEZ-EF based on new data. Twelve aviation biofuels pathways, produced using four technologies including Hydroprocessed Esters and …

Random Weighting Approach In Nonlinear And Hierarchical Regression Models, Yue Zhang

Open Access Dissertations

Nonlinear regression models with random and fixed effects are commonly used to analyze repeated measures data. Such data, consisting of repeated measurements taken on several individuals, typically arise in biological and biomedical applications amongst many other applications. The standard two-stage estimation (STS) method is intuitive and simple to implement in such circumstance, but the main difficulty is that not much is available on the sampling distribution of the resulting parameters estimates. In this work, we develop re-sampled versions of the least squares estimators (LSE) of the parameters in nonlinear regression as well as hierarchical nonlinear regression models. The approach we …

Adaptive Communication For Wireless Massive Mimo Systems, Ahmed A. Ibrahim

Open Access Dissertations

The demand for high data rates in wireless communications is increasing rapidly. One way to provide reliable communication with increased rates is massive multiple-input multiple-output (MIMO) systems where a large number of antennas is deployed. We analyze three systems utilizing a large number of antennas to provide enhancement in the performance of wireless communications. First, we consider a general form of spatial modulation (SM) systems where the number of transmitted data streams is allowed to vary and we refer to it as generalized spatial modulation with multiplexing (GSMM). A Gaussian mixture model (GMM) is shown to accurately model the transmitted …

Laboratory Safety Training Design And Evaluation For Aeronautical Engineering Technology Students In Part 147 Program, Xun Zhao

Open Access Dissertations

The FAA Part 147 program at Purdue University requires students in Aeronautical Engineering Technology (AET) major to take 1125 hours of laboratory works. Students are required to work in several different laboratory environments including airframe, powerplant, aircraft sheet metal processing, composite materials processing, electricity and electronics, non-destructive testing, aircraft system, maintenance practices and advanced manufacturing. Although course instructors emphasize laboratory safety, there is currently no pre-laboratory training for all students before they log any laboratory hours. Starting from 2004, occupational injuries and illness rates in the air transportation industry were shown to be much higher than the average for private …

Early Turn-Taking Prediction For Human Robot Collaboration, Tian Zhou

Open Access Dissertations

To enable natural and fluent human robot collaboration, it is critical for a robot to comprehend their human partners’ on-going actions, predict their behaviors in the near future, and plan its actions accordingly. Specifically, the capability of making early predictions can allow robots to determine the precise timing of turn-taking events and start planning and executing preparative tasks to take the turn. Such proactive behavior would save waiting time and increase efficiency and naturalness in collaborative tasks.

To that end, this dissertation presents the design and implementation of an early turn-taking prediction framework, centered around physical human robot collaboration tasks. …

Websites For Physics Demonstrations And Computer Simulations: A Non-Educational Quality Evaluation, Zheng Zhou

Open Access Dissertations

Scientific disciplines including mathematics, physics, and chemistry tend to adopt online resources, including websites and web applications, to demonstrate physical experiments and simulate scientific phenomena that are hard to observe and investigate in real world. The present study examined the existing collections of the websites and web applications created in academics for physics demonstrations and computer simulations. The present study discovered the existing collections of websites lack update and more recent resources. The present study conducted a state-of-the-art literature review to amend, update, and supplement the existing collection of the websites for physics demonstrations and computer simulations to a comprehensive …

Throughput And Efficiency Analysis Of Network-Coded Harq For Two-Way Wireless Systems, Hongyi Zhu

Open Access Dissertations

Due to the explosive increase of wireless subscribers, it becomes more crucial to efficiently use the limited spectrum resources. To improve spectral efficiency, this study explores network-coded (NCed) automatic repeat request (ARQ) in two-way wireless systems. NCed-ARQ has been proved effective in multi-cast and broadcast channels by utilizing the side-information overheard during retransmissions. However, most wireless networks are two-way where each node transmits and receives. In two-way wireless systems, more side-information can be used to enhance the throughput performance with network coding, which has not received much attention. In this study, we propose a new NCed-ARQ scheme with reverse-link assistance …

Modeling The Behavioral Landscape Ecology Of A Reintroduced Carnivore, Casey C. Day

Open Access Dissertations

The American marten (Martes Americana) is an endangered forest carnivore native to the Upper Midwestern United States and culturally significant to local Ojibwe tribes. In this region, the marten faces a number of potential threats to its persistence, including competition, predation, lack of prey availability, lack of recruitment, and lack of population connectivity. To evaluate how marten behavior affects the conservation and management of this species, I developed an individual-based model to simulate marten dispersal and home range establishment. In Chapter 2, I describe the model and the process of calibrating it to perform comparably to real-world martens. I also …

The Role Of Il-2rα-Dependent Signaling In Treg Development, Homeostasis, And Suppressive Function, Kevin Henry Toomer

Open Access Dissertations

Deletion of interleukin-2 (IL-2) or IL-2 receptor (IL-2R) subunits in mice causes lethal autoimmunity, establishing the vital contribution of IL-2R signaling to thymic development of Foxp3+ Tregs. However, precise mechanisms of IL-2-driven functional programming in Tregs and pathogenic autoreactive T cells remain undefined. To investigate these issues, we characterized a germline knockout (gKO) versus Treg-targeted conditional knockout (cKO) of the IL-2Rα chain (CD25) in mice. Both KO models developed lethal autoimmunity, but disease onset was delayed in CD25 gKO mice due to IL-2 deprivation among CD4+ and CD8+ T cells. Foxp3+ thymocytes from gKO mice showed greater reduction in Treg …

Engagement In Hiv Care And Treatment Among Haitian Americans, Esther P. Mathurin

Open Access Dissertations

HIV infection has remained a constant health problem in the United States and at the end of 2014, approximately 1.1 million people were living with HIV infection. During the HIV epidemic, Haitians were one of the four high-risk groups with the highest incidence of HIV infection known as the “4H” club identified by the Centers for Disease Control and Prevention. Although Haitians were listed among the “4H Club”, very few studies examined HIV infection among the Haitian American population in the US. Previous research reported that many Haitian Americans do not engage in HIV care and treatment and have worse …

Associations Between Physical Frailty And Cognitive Functioning Using Factor Analysis, Ni Sun-Suslow

Open Access Dissertations

While there are several proposed definitions, Fried et al. (2001) is the first study to define the physical characteristics of frailty. To date there have been few attempts to validate this criterion. Further, there is a long-standing and growing interest in the relationship between frailty and cognitive impairment. Few studies have investigated this relationship using an unmodified Fried criterion and cognitive measures beyond a mental status screener. We first examined whether the physical indicators of Fried phenotype cluster together to describe frailty syndrome using confirmatory factor analysis (CFA) and we further explored the association between frailty as a latent variable …

Middle East And North African International Students: Precollege Characteristics And Student Engagement, Mohamed Magdy Hassan Zaki Anis

Open Access Dissertations

Middle Eastern and North African (MENA) international students are among the largest and most rapidly growing populations studying at U.S. colleges and universities, yet little is known about their academic and social engagement on campus. The literature on this student population shows that MENA international students arrive in the United States with a set of particular challenges that inhibit their potential to fully engage academically and socially during their college experience. These challenges include language barriers, difficulty adapting to the American classroom teaching style, culture shock, and cultural differences (Abo Rabia, 2015; Al Murshidi, 2014; Burt, 2004; Carty et al., …

The Role Of General Psychological Processes In The Association Between Parental Rejection And Lgb Youth Internalizing Problems, Brian Edmund James Richter

Open Access Dissertations

Upward of 70% of lesbian, gay, and bisexual (LGB) youth experience some degree of negative parental reaction to their sexual orientation, which is problematic in light of data documenting an association between parental rejection and internalizing problems in these youth. While emerging studies have begun to study mediating factors, this research is limited and has significant gaps. To the author’s knowledge, the current study is the first to examine longitudinal data in this area as well as to investigate general psychological processes (i.e., factors common to all youth and known to be linked to youth mental health outcomes) that may …

Mesoscale Organized Convection In Climate Models: A Stochastic Scheme And Uncertainty Quantification, Gino Chen

Open Access Dissertations

Mesoscale organized convection is generally misrepresented in the large-scale convective parameterizations used in contemporary climate models. This impacts extreme weather events (e.g., Madden-Jullian Oscillation (MJO)) and the general circulation driven by the significant amount of latent heat released from mesoscale organized convection. Studies show that the missing processes could be partially recovered by embedding a 2D cloud-resolving model in each GCM columns, i.e., super- parameterization. Despite successfully resolving the MJO, the study of mesoscale organization mechanism across the CRM and GCM cells remains sparse in this multiscale modeling framework. We applied rigorous detection and hierarchical clustering algorithms on the 3-hourly …

Pulsatile Urea Excretion In Gulf Toadfish: Neuroendocrine Control And Potential Involvement In Chemical Communication, Maria C. Cartolano

Open Access Dissertations

Gulf toadfish (Opsanus beta) are well studied for their ability to produce and excrete urea as an alternate form of nitrogenous waste. Urea is only produced by a few adult teleost species in substantial quantities because its production is energetically costly compared to ammonia. Toadfish uniquely excrete urea in distinct pulses and the process is controlled physiologically by the stress hormone cortisol and the neurotransmitter serotonin (5-HT). Decades of research have ruled out several explanations for the adaptive advantage of this pulsatile urea excretion and the remaining hypothesis is that signals are release via urea pulses for chemical communication. However, …

An Exploration Of The Two-Dimensional Poroelastic Properties Of Oceanic Crust At The Formation Scale, William Zachary Billings

Open Access Dissertations

Implementations of three models were used to constrain permeability and vertical bulk modulus of oceanic crust using pressure data collected from CORKs at ODP/IODP Holes 1024C, 1025C, 1026B, 1027C, and 504B. The models are based on a one-dimensional half-space model, which interprets a given sinusoidal signal within formation as a combination of two signals produced by ocean tidal loading: an elastic signal at the measurement site that is in-phase with tidal loading, and a diffusive signal that travels through the formation to the instrument site. The aforementioned sites were chosen due to their thick sedimentation: the sediment layer is too …

Spinal Cord Neural Interface In Common Marmosets, Shubham Debnath

Open Access Dissertations

Patients suffering from paralysis or amputations can benefit from neural prosthetics to restore movement, such as control of a robotic limb for self-feeding or cursor control from communication. Current neuroprosthetics rely on stable, high quality recordings from chronically implanted microelectrode arrays in neural tissue. Microelectrodes implanted in brain tissue can be affected by multiple abiotic and biotic factors that lead to degradation in recording quality, ultimately resulting in electrode failure. While chronic electrophysiological recordings and electrode failure modes have been reported from larger non-human primates, studies in primary motor cortex from the marmoset model have not been previously described. The …

Effects Of Cognitively Guided Instruction On Teacher Created Opportunities To Engage Students In Problem-Solving, Uma Gadge

Open Access Dissertations

This study investigated the effects of a two-year long professional development (PD) program called Cognitively Guided Instruction (CGI) on teachers’ instructional practices for engaging students in problem-solving in elementary mathematics classrooms. The treatment involved sixteen days of CGI PD across two years. Forty-two and forty-seven teachers’ classrooms were observed and videotaped during first- and second-years, respectively. Videotaped classroom instruction was coded, and the resulting data were analyzed to compare students’ problem-solving opportunities between CGI and non-CGI classrooms. This study found that CGI teachers were more likely (than not), in comparison to non-CGI teachers to provide their students with various problem-solving …

Energy Diplomacy: The United States Of America And The Russian Federation, Arsen Gasparyan

Open Access Dissertations

New energy opportunities provide effective ways to advance energy superpowers’ foreign policy objectives. Oil and gas are capable of providing producer states with internal order and external influence and are thus a source of relative power. This research examines how energy shapes superpower nations’ foreign policy, analyzing cases of the United States of America and the Russian Federation after the end of the Cold War till the early 21st century with a diachronic selection of the most important developments. More detailed analysis covers the period from 2000 till the present to demonstrate how widely the U.S. and Russian national security …

Military Life, Intersectionality, And Deployment: The Social Experiences And Difficulties Of Mothers Who Stay Behind, Roberto Cancio Jr

Open Access Dissertations

Studies on the military family are important because it sheds light on the phenomenon of the family, it offers a unique insight into the largest single government employer in the nation, and issues addressed surrounding it can have important implications for the further development of both health and military policy. Prior research on families has consistently found that social relationships, especially close personal relationships, like marriage, have important health consequences. For that reason, understanding the impact of military life on spouses is of great importance. However, most studies have examined spouses individually, rather than concurrently as families. Empirical research has …

Examining The Effects Of Narrative-Based Interactivity And Its Two Types For Serious Digital Games, Chun Zhou

Open Access Dissertations

Health games have become an innovative tool for strengthening interventions, and these games are found to be effective in improving health outcomes. However, an underexplored question in ongoing research is why games are able to produce the desirable outcomes. To address this question, the current study evaluates the effectiveness of a specific game feature: interactivity. Considering that the effect of interactivity depends on how it is conceptualized and categorized, the current study focuses on two types of narrative-based interactivity: character-based interactivity and plot-based interactivity. Using a narrative-based digital health game, the current study examines how these two interactivity features affect …

Oral Health Related Quality Of Life, Dental Care Utilization, And Serostatus Disclosure Among Hiv-Positive Women In The Women’S Interagency Hiv Study (Wihs) Cohort, Carrigan Parish

Open Access Dissertations

Persons living with HIV are more likely than HIV-negative individuals to experience oral health problems, yet are also more likely to have unmet dental care treatment needs. Dental needs among HIV-positive individuals can also be more severe and difficult to manage compared to the general population, often contributing to the onset of opportunistic oral infections. Furthermore, dental problems in patients with HIV can be associated with low CD4 counts and poor immune function. Due to the underutilization of dental services, oral health problems and symptoms, especially those that are related to HIV infection, remain prevalent in this population. Neglected dental …

On The Combinatorics Of The Waldspurger Decomposition, James Mckeown

Open Access Dissertations

This thesis is comprised of an introduction, three chapters, and a brief appendix of figures. The introduction develops the theory of root systems and finite groups generated by reflections. For brevity and readability we occasionally argue by fiat, providing references for omitted proofs and further compensating with ample exam- ples. We establish conventions for ordering and coordinatizing root and weight vectors for the classical types and conclude with two central theorems from Waldspurger and Meinrenken. Chapter 1 introduces a combinatorial algorithm for studying the Waldspurger and Meinrenken theorems in the type A setting where the underlying reflection group is the …

Computational Insights Into The Structures, Mechanisms, And Chemical Properties Of Metal Complexes, Enzymes, And Bio-Molecules, Thomas J. Paul

Open Access Dissertations

In this thesis, we have focus on the following three projects: (1) the inhibition of amyloid beta aggregation, (2) structural and mechanical properties of amyloid peptides, and (3) complex biological systems of molecular recognition pertaining to hydrolysis. In the first project, we have looked at the inhibition of early and late forms of Aß peptides using heparin derived disaccharides, small molecules, and a Rhenium centered photoluminescence probe. We have determined and characterized the most relevant binding sites of these complexes to both the monomeric and fibrillar forms of the Aß peptide. Currently, the aggregation of biomolecules has been implicated in …

Examining Periodontal Disease And Cardiovascular Disease Risk - Assessing The Feasibility And Acceptability Of Screening In The Dental Care Setting, Richard H. Singer

Open Access Dissertations

Cardiovascular disease (CVD) is the leading cause of death for both men and women in the U.S. and is responsible for 1 in 4 deaths annually. While mounting evidence points to an association of periodontal disease (PD) with a significant increase in the risk of CVD, independent of established CVD risk factors, this association has not been studied in Hispanic/Latino populations. Dental care settings offer an untapped health care setting to expand access to screening and early identification of cardiovascular disease (CVD) risk. However, little is known about dentist or patient viewpoints towards CVD screening in the dental office. The …

Modulation Of Cloud Cluster Propagation By Super Cloud Clusters, Joaquin Esteban Blanco

Open Access Dissertations

A series of symmetric, aquachannel simulations obtained with the WRF model are used to study the propagation of tropical Cloud Clusters (CCs) in association with eastwardmoving Super Cloud Clusters (SCCs). The analysis is carried out using the precipitation field in time-longitude coordinates. Two independent but complementary methods are used: the first, from a local approach, involves a CC-tracking algorithm, while the second uses Lagrangian Trajectories in a non-local framework. It is found that the background flow in low-to-mid-levels advects the CCs either eastward or westward depending on model climatology, proximity to the SCC axis, and latitude. Moreover, for most analyzed …

"Terrorists” Imaginaries: Social Exclusion, Queerness, Repressive Apparatus And The Emergence Of Post-Religious Terrorism In Contemporary Maghrebian Francophone Literature And Film, Thouraya Ferid

Open Access Dissertations

I examine the narratives imaginaries of Terrorism among some authors and filmmakers between 2007 and 2012. I argue that these oeuvres give rise to a new understanding of terrorism that is rooted in a series of traumatic experiences endured by the subject. These humiliations lead to the urgent need of a radical revenge: The terrorist act. The new terrorism is rooted in the "radical multitude" of oppressed singularities. Literary and cinematic fiction from the Maghreb can be considered as what Saldivar in "Unsettling Race, Coloniality and Caste” (2007), calls a "locus of enunciation" on terrorism. This enables the emergence of …

Giving Voice To Underserved Foreign-Born Latino Youth: Trauma, Stress, And Health In The Primary Care Setting, Ashley Nicole Marchante-Hoffman

Open Access Dissertations

Exposure to potentially traumatic events (PTEs) is common in the United States and may be more frequent among foreign-born Latino youth. Research has shown that PTEs negatively affect mental health outcomes, such as depression and anxiety. However, less is known about physical health outcomes during childhood and adolescence. Furthermore, foreign-born Latino youth, who are often a high-risk group, have been largely neglected in the trauma literature. Thus, the purpose of this study was to: (1) examine rates of pre-, during, and post-migration PTEs in foreign-born Latino youth and (2) assess the relationship between PTEs and markers of physical health problems …

Developing, Evaluating And Utilizing A Measurement Approach To Index The Fidelity Of Subjective Reports During A Sustained Attention Task, Joshua Daniel Rooks

Open Access Dissertations

In the current program of research, a Hierarchical Linear Modeling (HLM) statistical approach was utilized to develop a novel metric of the veridicality of one’s subjective reports on the state of their attention. This metric, termed the Fidelity of Subjective Reports (FSR), was statistically operationalized as the within-individual correspondence between self-report and behavioral performance measures of attention on the Sustained Attention to Response Task (SART). The first objective was to identify the ideal window of behavioral performance data on the SART to relate to subjective reports. Secondly, the construct validity for the FSR, based on a preliminary conceptual model of …