GaInAsSb is a promising material for mid-infrared devices such as lasers and detectors because it is a direct band gap material with large radiative coefficient and a cut-off wavelength that can be varied across the mid-infrared (from 1.7 to 4.9 μm) while remaining lattice matched to GaSb. On the other hand, the potential of the alloy is hampered by predicted ranges of concentration where the constituents of the alloy become immiscible when the crystal is grown near thermodynamic equilibrium at typical growth temperatures. There have been efforts to extend the wavelength of GaInAsSb alloys through such techniques as digital alloy growth and non-equilibrium growth, but most of the compositional range has for a long time been inaccessible due to immiscibility challenges. Theoretical studies also supported the existence of thermodynamic immiscibility gaps for non-equilibrium growth conditions. Lower growth temperatures lead to shorther adatom diffusion length. While a shorter adatom diffusion length suppresses phase separation, too short an adatom length is associated with increased defect formation and eventually loss of crystallinity. On the other hand, hotter growth temperatures move epitaxial growth closer to thermodynamic equilib- rium conditions, and will eventually cause phase separation to occur. In this study thick 2 μm; bulk GaInAsSb layers lattice-matched to GaSb substrates were grown across the entire (lattice-matched) compositional range at low growth temperatures (450°C), including the immiscibility region, when grown under non-equilibrium conditions with MBE. High quality epitaxial layers were grown for all compositions, as evidenced by smooth morphology (atomic force microscopy), high structural quality (X-ray diffraction), low alloy fluctuactions (electron dispersive spectroscopy in cross sectioned samples), and bright room temperature photoluminescence. Because initial theoretical efforts have suggessted that lattice strain can influence layer stability, we have studied effects of strain on alloy stability. Unstable and metastable alloys were grown hot enough for the onset of phase separation, then progressively strained and characterized. We show that strain is effective in suppressing phase separation. Finally, we performed time-resolved carrier lifetime measurements for InAsSb alloy with low concentrations of Ga to investigate the role of Ga in influencing nonradiative carrier recombination. There have been studies on non-Ga containing antimonide structures (InAsSb, InAs/InAsSb) that show long carrier lifetimes, which suggest that Ga plays a role in reducing carrier lifetime, because Ga-containing structures such as InAs/GaSb superlattices have much shorter carrier lifetimes. Ga may reduce carrier lifetime through native defects that increase background carrier concentration, or that create mid-gap electronic states. Here, a series of GaInAsSb alloys were grown with low to zero Ga concentration. No difference in carrier lifetime was observed between Ga and Ga-free structures, and minority carrier lifetimes > 600 ns were observed. Additional work remains to be done to obtain background carrier densities in the samples with Hall measurements.

Muscle fatigue is universally experienced in daily life, from recreational physical activity to the workplace. However, our ability to estimate fatigue is limited. Several attempts have been made to mathematically model the effects of fatigue, such as how long a muscle contraction may be sustained, known as `endurance time.' However, these simple models of endurance time are limited to static contractions when the body is not moving, but muscles are contracted. This research aims to advance a previously proposed analytical model of muscle fatigue to represent complex tasks such as with rest intervals and dynamic contractions. Multiple methodologies were employed to assemble data to examine the model prediction accuracy, including 1) compiling previously published data involving intermittent rest intervals (i.e., meta-analysis); 2) experimentally collecting data on intermittent fatigue for shoulder flexion as it is not well represented in the literature; and 3) experimentally collecting data on fatigue during a dynamic task for elbow flexion as dynamic tasks have been virtually ignored in fatigue literature. The results of these investigations indicate that a mathematical model of fatigue is reasonably accurate in predicting an average fatigue response across multiple subjects for both intermittent and dynamic tasks, but does not currently reflect the often wide variation in muscle fatigue development that is observed between individuals. Accordingly, this type of modeling approach may have value for general assessments of fatigue accumulation, but will need further development and modification to better represent individual characteristics.

Francisco Mignone was born in São Paulo on September 3, 1897 and died on February 19, 1986. A representative of Brazilian Nationalism and one of the most influential national composers, Mignone was active and prolific through his entire life. Few works of Francisco Mignone's late period are known and performed; nevertheless the interest in Mignone's work has been growing. Since many of his works are not published, efforts to discuss and prepare performance editions of his scores are of great importance. The Concertino para clarineta e fagote is representative of Francisco Mignone's last compositional period that, although written using a universal way of treating dissonances, intervals, or different pitch hierarchies, it is very Brazilian in its essence. The present performance edition highlights the human aspect of Mignone's character through an overview of the composer's last compositional period and compositional techniques. This essay contextualizes the Concertino within the composer's career and presents a performance analysis of the piece. It also contains a list of Mignone's works for the bassoon and a list of prizes awarded to the Brazilian composer.

Motor learning is an important component of daily life: humans are constantly adjusting their movements and acquiring new skills in order to meet the demands of their environment. Motor learning also contributes to neurorehabilitation, so it is therefore important to understand the neural mechanisms underlying motor learning so that these mechanisms can be exploited to promote neurorehabilitation after central nervous system injury. This dissertation focuses on three distinct methods of improving motor learning in healthy adults. In Chapter 2, we tested the effects of perturbation schedule on retention of a locomotor adaptation. The results of this work demonstrated that introducing a perturbation slowly and incrementally versus introducing a perturbation abruptly produces similar behavioral expression of locomotor memories across days. In Chapter 3, we tested whether administering 200 mg of caffeine immediately after practicing a novel motor skill enhances retention of that skill 24 hours later. However, we found that post-practice caffeine administration did not significantly improve retention of the motor skill. In combination with previous reports, these results suggest that the effects of post-practice caffeine administration are likely task-specific. In Chapter 4, we examined the interactions between hand use, practice-dependent plasticity and motor learning. We found that experimentally immobilizing the left hand for 8 hours facilitates subsequent practice-dependent changes in corticospinal excitability in a topographically-specific manner. In contrast, immobilization did not facilitate practice-dependent changes in TMS-evoked thumb movements, nor did it promote learning or retention of a ballistic motor skill. Although it is thought that practice-dependent changes in corticospinal excitability are an important and potentially causal contributor to motor memory, the results of this work indicate that experimentally enhancing practice-dependent changes in corticospinal excitability is not sufficient to promote motor learning. In sum, although none of the experimental interventions tested here substantially improved motor learning, these experiments highlight the influence of various mechanisms on motor learning in the intact nervous system.

Hurricane Katrina made landfall on the American Gulf Coast on August 29, 2005. Biloxi, Mississippi, a small town on the coast, was one of the towns devastated by the storm. A decade after the storm, recovery remains an ongoing process. My ethnographic research in 2006, 2010, and 2011 and media and historic document analysis throughout these ten years explore this recovery process and what pre-disaster cultural, social, political, and economic issues have shaped Biloxi and Biloxians' recovery. The small coastal city of Biloxi sits on the Mississippi Sound of the Gulf of Mexico. The city's history and residents' identities are intertwined with this waterfront location. Biloxians rely on the Gulf for recreation and job opportunities, particularly in the long-standing seafood and tourism industries. Scattered piers are filled with recreational and shrimping boats. Casinos dot the shoreline where seafood processing plants once stood. Many Biloxians still proudly identify with the city's coastal location, neighborhoods they were raised in or lived in before Katrina, their perceived socioeconomic class status, and their own and their ancestor's racial, ethnic, and national identities. However, Biloxi's waterfront location also makes the city prone to hurricane strikes. Historic storms like Camille in 1969 and Fort Lauderdale in 1947 have affected the city's development and influenced residents' beliefs and behaviors during their preparation for Katrina. Biloxians were aware of Katrina's predicted landfall in the days and hours before the storm, but this history of hurricanes influenced many residents' decisions to remain in the city for the storm. Many residents I spoke to described their belief that survival in previous storms indicated they would survive Katrina. Other pre-Katrina processes influenced Biloxians' preparations for, coping with, and response to the disaster, as expected in vulnerability theory. Poorer and working class residents were less able to prepare for or evacuate before the storm, if they chose to do so. Residents in higher risk neighborhoods like East Biloxi found themselves affected more severely by the storm, often losing much of their homes and lives. Biloxians' with less political and economic power struggled to keep their voice heard as city and other government officials laid the framework for recovery. Pre-Katrina Biloxians' cultural, political, and economic inequalities directly affected the recovery process. To better understand these influences, in this research I use a political economy approach to describe and analyze Biloxi's recovery from Katrina. To strengthen this analysis, I have also drawn on theories regarding vulnerability and resilience, risk and uncertainty, and cultural-historical context. Each of these approaches contributes to a better understanding of how post-disaster recovery processes work - particularly in the case of post-Katrina Biloxi. This work also builds on disaster anthropology and social science research that rejects the concept of disasters as isolated events and instead argues that disasters are influenced by broader and long-standing cultural, political, and economic processes. In this work I also bring this argument for a holistic approach into long-term disaster recovery. The holistic anthropological approach to the post-Katrina Biloxi that I have used here reveals the importance of understanding a range of facts and processes that exist before, during, and after a disaster to explore the recovery process. Post-Katrina Biloxi is as much a product of pre-Katrina Biloxi as it is a product of the effects of the hurricane itself.

Autism Spectrum Disorder (Autism Spectrum Disorder) is a neurodevelopmental syndrome characterized by impairment to social communication adjoined by the presence of rigidity, restricted interests, and/or repetitive behaviors. Diagnosis of Autism Spectrum Disorder recently shifted from a series of pervasive developmental disorders recognized in the 4th edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV-TR; American Psychiatric Association, 2000) to a single, comprehensive diagnosis in the 5th edition of the same manual (DSM-5; APA, 2013). To evaluate the appropriateness in this shift in diagnostic practice, the current study evaluates the consistency in symptom presentation amongst the previous DSM-IV-TR diagnoses. Additionally, this study identifies several novel considerations for Autism Spectrum Disorder symptom presentation in high ability youth. Thus, the current study addresses broad considerations for discrete versus continuous symptom presentation in Autism Spectrum Disorder, as well as contributes to the limited literature addressing Autism Spectrum Disorder symptom presentation features in high ability youth. A review of literature on theory, conceptualization, and assessment of Autism Spectrum Disorder is provided, as well as a review of relevant literature for high ability youth diagnosed with Autism Spectrum Disorder. Progression of Autism Spectrum Disorder diagnosis is discussed, with emphasis upon the current debate regarding shifts from utilization of many diagnoses to a single, comprehensive diagnosis. Next, unique challenges associated with Autism Spectrum Disorder in high ability youth are identified, including current conceptualization, assessment, and treatment considerations. Due to identified gaps in consistent understanding of Autism Spectrum Disorder presentation, including Autism Spectrum Disorder in high ability youth, the author conducted two complementary studies. The first of these studies evaluated consistency in parent ratings on Autism Spectrum Disorder screening tools across previously used diagnostic labels (i.e., Autistic Disorder (AD), Asperger's Syndrome (AS), and Pervasive Developmental Disorder, Not Otherwise Specified (PDD-NOS)) now subsumed under Autism Spectrum Disorder diagnostic criteria in the DSM-5. The second study analyzed Autism Spectrum Disorder symptoms reported by parents of high ability youth. Data collection for this latter study included a novel research measure intended for identifying symptoms associated with high ability Autism Spectrum Disorder. Items on this form were derived through a card sort of items included in current symptom screening tools completed by content area experts. Additionally, this novel research measure included an open-ended item for parents of high ability youth to report additional symptoms. Results from the first study suggest that parents of children diagnosed with AD, AS, and Pervasive Developmental Disorder, Not Otherwise Specified do not differentially report symptoms on two current Autism Spectrum Disorder screening tools: (1) The Social Responsiveness Scale (SRS; Constantino & Gruber, 2005) and (2) the Autism Spectrum Screening Questionnaire (ASSQ; Ehlers, Gillberg, & Wing, 1999). Results from the second study provide evidence of parental perceptions of several nuances in symptom presentation associated with high ability youth with Autism Spectrum Disorder. Specifically, parents frequently endorsed impairment in development and maintenance of social relationships; however, insight into these weaknesses was not consistently reported as impaired. Additionally, restricted interests were acknowledged, with some parents identifying academic or pseudo-academic subjects as common areas of interest. The collective findings from these studies provide evidence of broad consistency in Autism Spectrum Disorder symptom presentation across previously used diagnoses, yet also unique symptom features for high ability youth. Implications for education, clinical practice, and research in both Autism Spectrum Disorder and twice-exceptionality are discussed.

Photoreceptors are highly compartmentalized neurons in the retina, and they function by detecting light and initiating signaling through the visual network. The photoreceptor contains several compartments including the outer segment (OS) which is a sensory cilium for detecting photons and the inner segment (IS) that carries out important modulatory functions via its resident channels and transporters. Those proteins are membrane proteins that function together to shape electrical properties of the cell membrane during both rest and active states. Therefore it is essential to maintain proper function of the membrane proteins in the IS. One important way to regulate the function of a membrane protein is via controlling its trafficking to ensure a proper amount of the protein in the proper cellular compartment. To date, little is known about how IS membrane protein trafficking is controlled in photoreceptors. In this study, our goal is to understand those mechanisms using cell biology and biochemistry approaches. To achieve the goal, we investigated trafficking of two unrelated IS resident proteins: the hyperpolarization-activated cyclic nucleotide-gated channel 1 (HCN1) that mediates a feedback current in photoreceptors, and the sodium potassium ATPase (NKA) which maintains the basic electrochemical property of the cell. In order to study trafficking of HCN1, we first investigated the dependence of HCN1 trafficking in photoreceptors on TRIP8b, an accessory subunit that influences trafficking of HCN1 in hippocampal neurons. By studying TRIP8b knockout mice we found that TRIP8b is dispensable for HCN1 trafficking in photoreceptors but required for maintaining the maximal expression level of HCN1. Since we revealed that HCN1 trafficking can be regulated in a cell-type specific manner, we subsequently focused on the amino acid sequence of HCN1 to identify novel trafficking signals that function in photoreceptors. By examining localization of a series of HCN1 mutants in transgenic Xenopus photoreceptors, we discovered a di-arginine ER retention motif and a leucine-based ER export motif. These two sequence motifs must function together to maintain equilibrium of HCN1 level between the endomembrane system and the cell surface. The study of HCN1 uncovered a mechanism for the photoreceptor to control membrane protein trafficking via the early secretory pathways. To reveal additional trafficking machineries in photoreceptors, we investigated trafficking of NKA. We first tested for an interaction with ankyrin, an adaptor protein that regulates NKA trafficking in epithelial cells, and found these proteins do not co-localize in photoreceptors. We then aimed to identify novel trafficking signals by studying the trafficking behavior of two NKA isozymes: NKA-α 3 and NKA-α 4. When expressed in transgenic Xenopus photoreceptors, these two proteins localize to the IS and the OS respectively. By studying localization of multiple chimeras and truncation mutants, we found that the distinct localization pattern is due to a VxP OS/ciliary targeting motif present in NKA-α 4. Since NKA-α 4 is naturally expressed in the ciliary compartment of the sperm, our finding in the photoreceptor suggests a mechanism for NKA-alpha 4 trafficking in its native environment. Overall, our studies of HCN1 and NKA together provide new insights into controlling membrane protein trafficking in photoreceptors and help establish the basics for future therapeutic intervention targeting trafficking pathways that are linked to about one third of proteins reported in retinal diseases.

Student-teacher relationships have been studied by numerous researchers from a variety of perspectives. Evidence consistently suggests that the quality of student-teacher relationships can have a profound impact on children’s social and cognitive development. Although researchers seem to agree on this point, their theoretical conceptualizations of the relationships and how they measure them are often quite different. This study provides empirical insights for both measurement integration and theory integration regarding students’ internal relationship representations. Items from 14 different student-teacher relationship instruments were systematically combined and administered as a composite instrument to 628 college students. The participants responded to all items in reference to a single, recent relationship with a high school instructor. This allowed comparative examination of the original 14 scales independently for internal consistency and predictive validity. The study also examined a hypothesized multidimensional structural model of students’ internal representation of their relationship with a teacher based off relational schema theory. An alternative, more parsimonious model was examined as well. The hypothesized model was not supported by the data. The study demonstrated that multiple measurement models of various items could produce acceptable fit. The study provided evidence as to which of the 170 items from the 14 original scales most closely measure the core of student-teacher relationship quality. The study exemplified the method effect dangers of negative item wording. Finally, the study provided strong evidence for conceptualizing student-teacher relationships as a single, global relationship quality construct.

The Iowa Flood Center (IFC), a unit of The University of Iowa's IIHR - Hydroscience & Engineering, and the Iowa Department of Natural Resources are developing a statewide floodplain boundary dataset to provide information that is critical to proper flood mitigation planning. During flooding, soil loss from agricultural land, in addition to inundation, can have a substantial economic impact on an agricultural state like Iowa. The ability to identify areas with a high potential to experience scour during flooding could assist farmers and land owners in making better land management decisions. Currently, the IFC statewide floodplain mapping program is creating annual exceedance probability floodplain data for all Iowa streams. The effort described herein has developed methods to take advantage of this large dataset, applying uniform open channel flow theory to spatially characterize scour potential using custom tools created with GIS model builder. The results of this thesis are being used by the Iowa Natural Heritage Foundation (INHF) and the IFC to develop a program through which certified crop consultants can help farmers make more informed land management decisions based on risk of flood related soil loss.

This study examined the effects of perceived sleep deprivation on psychological well-being using multiple linear regression techniques on a longitudinal, multi-institutional sample of students at four-year universities and colleges. Using a College Outcomes model as a theoretical foundation, this study examined perceived sleep deprivation's influence on psychological well-being at the end of four academic years, while controlling for institutional and student background characteristics that are theoretically associated with psychological well-being. Pre-test and post-test data from the Wabash National Study of Liberal Arts Education (WNS) created findings suggesting sleep deprivation is positively related to total psychological well-being and the six subscales composing the complete measure (self-acceptance, autonomy, environmental mastery, positive relationships with others, purpose in life, and personal growth). This study contributes to college outcome models by supporting the claims for the importance of healthy, habitual sleep in relation to student's ability to achieve overall psychological well-being, as well as the six subscales of the total model. This study has implications for higher education and public health policy, including practical applications for those involved with higher education, including students, staff, faculty, and administrators.