cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.25549/usctheses-c3-5708
title: Bio-inspired tendon-driven systems: computational analysis, optimization, and hardware implementation

description: This thesis work focuses on the design and optimization of tendon-driven systems. One of the chief reasons these systems can be termed “bio-inspired” is due to the fact that they produce forces and movements via tendons which are connected to actuators and have uni-directional action (they can only pull, not push). In particular, the human hand sets itself apart from the rest of the body’s neuromuscular systems in that there are no muscles in the fingers themselves: all the muscles are proximal to the fingers. The study and analysis of tendon-driven hands and fingers suggest that i) the human hand is mechanically optimized for grasping capabilities and ii) use of bio-inspired principles in robotic systems can drastically improve force-production capabilities, grasp strength, and stiffness control performance. Some of the bio-inspired principles which are proven throughout this work to be very beneficial in robotic systems are asymmetry and skewed combinations of design parameters. This work not only has strong implications for the design of commercial robotic and prosthetic hands, but also broadly seeks to inspire creativity in design and optimization routines for complex problems in many different engineering disciplines.
DOI: 10.25549/usctheses-c3-7713
title: Is the likelihood of waterfowl presence greater on conserved lands?

description: Waterfowl are one of our Nation’s most precious and abundant natural resources, and preserving habitat well suited to their needs has long been a goal of private and public entities alike. In this study, I focused on the American Black Duck (Anas rubripes), a species seeing a large decline in numbers since the mid 20th century. Using a satellite telemetry dataset collected by Ducks Unlimited during 2008 and 2009 in the context of the Protected Areas Database of the United States (PAD), I addressed the land use habits of A. rubripes to assess the efficacy of costly conservation efforts implemented through conservation easements and the maintenance of wildlife refuges and management areas. Most analyses were conducted at the stopover level, grouping telemetry points within a 0.5 decimal degree diameter. By creating distributions and studying correlations, this study finds that during wintering months A. rubripes registered more telemetry points in PAD lands where hunting is allowed in-season; during migration, lands outside of the PAD were more frequently used. This could be attributed to waterfowl specific management practices creating prime habitat during wintering and food needs being fulfilled by residual agricultural products during migration. This suggests an increased importance of management efforts in wintering habitats. Climate variables were also assessed to test reported influences of temperature and precipitation on distribution and stopover behaviors, but study data did not demonstrate a correlation between stopover length and temperature or precipitation at arrival and departure. A finer scale geospatial analysis using more detailed information about hunting status and protection level is recommended to further interpret available data.
DOI: 10.25549/usctheses-c3-4817
title: Effective strategies superintendents utilize in building political coalitions to increase student achievement

description: Superintendents of public urban schools face tremendous pressure to increase student achievement. Leadership at the district level, particularly the relationship between the superintendent and the governing board of education, has a direct impact on student achievement. The purpose of this study was to find strategies that school superintendents utilize to create political working coalitions that lead to school reform and student achievement. ❧ Three research questions were used on the design of this mixed-methods study. Data was collected though six designed standardized open-ended interviews and a self-report online survey that was sent to superintendents and board members of 30 Southern California school districts with similar characteristics. ❧ The research study provided several key findings. First, superintendents identified that strategies to communicate with the board, to achieve goals and understand the political nature of the position, are necessary for a successful superintendency. Second, board members identified that strategies to communicate with the board, strategies to establish positive working relationships between the superintendent and the board, and knowledge of district management and leadership skills, are necessary for a successful superintendency. Finally, superintendents self-reported that a combination of traditional academic programs, prior leadership experiences, and working with mentors and peers provided valuable experiences to prepare them for the challenges of the superintendency.
DOI: 10.25549/usctheses-c3-6050
title: Innovative social support systems and the recruitment and retention of international students in U.S. higher education

description: As the notion of globalization becomes more and more important, students from all over the world decide to study abroad in order to gain multicultural experiences. The United States has always been the leading country, with the most international enrollment; yet the increasing demand for enrollment in universities between English-speaking countries becomes a source of competition. Thus, the purpose of this study was to look at innovations in the social support system for international students in U.S. higher education, and examine whether a successful social support system positively impacts international student recruitment and retention. The results have shown that, with sufficient institutional support and leadership, innovative social support programs positively impact student retention.
DOI: 10.25549/usctheses-c3-8143
title: Genetically-encoded probes for visualizing protein trafficking dynamics in living neurons

description: Here I describe the development of genetically-encoded probes for visualizing the trafficking of neuronal proteins in living cells.  The probes are derived from a diverse library of small fibronectin domains that resemble antibodies with the advantage of containing no disulfide bridges which facilitates proper expression and folding inside cells.  Using the directed evolution technique mRNA display I selected fibronectins that specifically label the voltage-gated potassium channel Kv4.2 auxiliary subunit KChIP and Ca2+/Calmodulin-dependent Kinase II (CaMKII) α, proteins both involved in the regulation of long-term potentiation.  As a fusion to GFP the CaMKIIα probe reveals the rapid translocation of kinase to post-synaptic densities upon excitatory stimulation.  It also reveals a hitherto unreported localization pattern of large kinase clusters in the cell body.  These cell body CaMKIIα clusters rapidly and reversibly disperse upon excitatory stimulation in a Ca2+-dependent manner and may represent a new mechanism by which neurons localize inactive CaMKIIα.  These Fibronectin intrabodies generated by RNA display (FingRs) combine the advantages of recombinant DNA such as fluorescent fusion tags with the ability to visualize endogenous proteins.  This technology is a leap forward in visualizing the trafficking dynamics of native proteins in living cells.
DOI: 10.25549/usctheses-c3-8268
title: Student perceptions of the relationship between Web-based instructional tools and perceived attainment of intended learning outcomes

description: With the advent of and continual adaptations related to distance learning, there is a recognized need for up to date research in the area of effectiveness of online education programs. More specifically, assessing the capacity to attain academic goals by use of asynchronous and synchronous learning management systems (LMS) that power distance learning platforms requires further evaluation. Therefore, this mixed methods study aimed to address perceptions of the LMS associated with the MAT@USC, the online Master of Arts in Teaching graduate program affiliated with the University of Southern California and their technology partner, 2tor. ❧ More specifically, research within this study was designed to assess student perceptions of the abilities of the various asynchronous and synchronous web-based tools found within the LMS to assist in the perceived attainment of academic outcomes. The study included 33 participants enrolled in the MAT@USC distance learning program and residing in locations around the United States and internationally. A post-only Likert scale survey was employed to collect quantitative data related to perceptions of the ability of various web-based instructional tools to assist in the perceived attainment of academic learning outcomes. Descriptive statistics revealed preference for the live synchronous Class Time sessions, live synchronous Chat Pod messaging, and asynchronous ongoing email communication. Two-tailed t-tests and ANOVA results indicated minimal significance related to prior online experience, attendance in technology trainings, and favored tools in core and pedagogy courses. ❧ Additionally, qualitative feedback related to each tool was gathered via an open-ended response portion of the survey, as well as through observations of twenty-one recorded Class Time sessions. The qualitative findings within this study were consistent with the research detailing the benefits of clarification and immediacy of feedback in the online learning setting.
DOI: 10.25549/usctheses-c3-4934
title: Beliefs and perceptions of DPRK teachers of English towards CLT instruction and factors that influence program implementation

description: Similar to its neighboring countries of China, South Korea, and Japan, the Democratic People's Republic of Korea (DPRK) (also known as North Korea) has made English a compulsory subject for middle school to university level students, and teacher training programs based on the Communicative Language Teaching (CLT) approach have also been implemented.  This mixed-methods study was conducted at the Pyongyang Computer English Refreshing Center, a program where ""native"" English speaking teacher educators provide professional development to DPRK teachers of English using curriculum based on the CLT approach.  The aims of this study were to understand the DPRK teacher-participants' beliefs and perceptions towards the CLT approach and to explore the contextual factors (social, historical, cultural) that influence program outcomes.
DOI: 10.25549/usctheses-c3-4529
title: On the proportion of derangements in cosets of primitive permutation groups

description: Motivated by questions arising in connection with branched coverings of connected smooth projective curves over finite fields, I am studying the proportion of fixed point free elements (derangements) in cosets of normal subgroups of primitive permutations groups. Using the Aschbacher–O’Nan–Scott theorem for primitive groups to partition the problem, I provide complete answers for affine groups and groups which contain a regular normal nonabelian subgroup.
DOI: 10.25549/usctheses-c3-8330
title: Identification and characterization of post-translational modifications on histones: an on-line top-down mass spectrometry workflow for analysis using ProSight PTM

description: The importance of histones for DNA management cannot be understated. From rearrangement to regulation of expression, histones act as the principle effectors of DNA availability and storage. A majority of diseases involve errors in gene expression; frequently chemical changes to the DNA and histones comprising the epigenome are to blame. Mass spectrometry has recently exploded as a prime method for studying histones. Advancements in the resolution and sensitivity of mass spectrometry machinery have allowed histone investigation to expand beyond traditional protocols. Namely, the ability to study intact histones without the need for enzymatic digestion beforehand has allowed more information to be gained about histones, which was previously unobtainable. An on-line intact histone workflow was developed to establish a protocol for identifying different histone types in a sample. Characterization of chemical modifications on the histones was accomplished using an online version of the ProSight PTM software. From this method, the four histones of the nucleosome octamer were identified and several post-translational modifications were detected. Expanded application of the developed workflow could be used to better understand known modifications and detect novel modifications. Additional adaptations of this analytical procedure could be used to test the epigenetic signals between different physiological conditions and find indicators of disease states. The initial success of the developed methodology for identifying modifications to histones provides the foundation for a rapid expansion of knowledge about the human epigenome.
DOI: 10.25549/usctheses-c3-8434
title: Syntactic alignment models for large-scale statistical machine translation

description: Word alignment, the process of inferring the implicit links between words across two languages, serves as an integral piece of the puzzle of learning linguistic translation knowledge. It enables us to acquire automatically from data the rules that govern the transformation of words, phrases, and syntactic structures from one language to another. Word alignment is used in many tasks in Natural Language Processing, such as bilingual dictionary induction, cross-lingual information retrieval, and distilling parallel text from within noisy data. In this dissertation, we focus on word alignment for statistical machine translation. ❧ We advance the state-of-the-art in search, modeling, and learning of alignments and show empirically that, when taken together, these contributions significantly improve the output quality of large-scale statistical machine translation, outperforming existing methods. We show results for Arabic-English and Chinese-English translation. ❧ Ultimately, the work we describe herein may be used for any language-pair, supporting arbitrary and overlapping features from varied sources. Finally, our features are learned automatically without any human intervention, facilitating rapid deployment for new language-pairs.
DOI: 10.25549/usctheses-c3-8559
title: Design and discovery of small molecules inhibiting the interaction of cellular LEDGF/p75 and HIV-1 integrase

description: Cellular transcription co-activator p75, also known as lens epithelial-derived growth factor (LEDGF/p75), plays an essential role in HIV-1 IN-led integration of viral DNA into the human genome.  Designing compounds to disrupt LEDGF/p75-IN complexes serves as a novel mechanistic approach different from current antiviral therapies.  The evolution of HIV has afforded the viral species to adapt to external therapeutic pressure and raltegravir-resistant viral strains have been well documented, increasing the need for new IN inhibitors with a different mechanism of action.  Mechanistic studies show the majority of reported IN inhibitors effectively chelate with a magnesium ion in the catalytic active site, a region topologically different from the LEDGF/p75 binding site.  Thus, key LEDGF/p75 K364 I365 D366 amino acid residues from the IN binding domain laid a foundation for ligand-based pharmacophore models.  Herein we report funding from the National Institute of Allergies and Infectious Diseases and the California HIV/AIDS Research Program led to the discovery of more than 100 novel small molecules that successfully inhibited LEDGF/p75-IN complex formation with IC50 values below 50 µM.  A small molecule database of 365,000 was searched and compounds that had fitness values above 2.0 were selected for prescreening in an in vitro luminescent proximity assay.  Lead inhibitors expanded into training sets using substructure similarity tools and ADMET filters led to the discovery of four novel classes of LEDGF/p75-IN inhibitors and additional potential lead inhibitors.  Seven antiviral LEDGF/p75-IN inhibitors were identified from this study.
DOI: 10.25549/usctheses-c3-6495
title: Sources of stability and change in the trajectory of openness to experience across the lifespan

description: This dissertation examined sources of stability and change in openness to experience across the lifespan. The data came from the Swedish Adoption/Twin Study of Aging (SATSA), a large longitudinal study of twins that included up to six measurement occasions of openness. Study 1 examined the longitudinal trajectory of openness and variables hypothesized to account for individual differences in level and change in openness. Using twins as individuals (and adjusting for the correlation between twins in the modeling), results from phenotypic latent growth curve modeling confirmed previous literature that openness exhibits small but significant decline in older adulthood. Model estimates indicated a total decline of about 1.5 points in openness over twenty years, generally occurring after age 60. Thus, age accounted for the decline in openness. Males and females were not significantly different in level or rate of decline. Education was important in predicting individual differences in level of openness, but not decline. Self-rated health, activities of daily living, and cardiovascular disease did not explain individual differences in level or decline in openness. Study 2 examined the relationship between openness to experience and death. Results from two methods of modeling growth and survival, adjusted for entry age, sex, education and twinness, suggested that the slope of openness was significantly associated with death such that individuals who had a faster rate of decline were at a greater risk for death. Level of openness (mean openness at age 65) was unrelated to risk for death. The overall results from study 1 and study 2 suggested that decline in openness was normative across older participants and is perhaps best conceptualized in relation to theories of terminal decline - the period of time prior to death during which multiple domains have been found to decline. Study 3 examined the pattern of genetic and environmental influences across the longitudinal trajectory of openness. Results from a biometric latent growth model (a latent growth model combined with a Cholesky decomposition model) suggested that a reduced additive genetic (A) and nonshared environment (E) model provided the best fit. The AE model estimates suggested that the individual differences in level, linear slope, and quadratic slope were primarily accounted for by genetic influences. For both men and women additive genetic influences generally increased with age. For men, nonshared environmental influences increased similar to genetic influences but then declined after age 65. For women, the contribution of nonshared environmental influences declined steadily from age 40. The findings from Study 3 give initial support to one theory of personality development that has suggested that normative patterns of change in adult personality would be explained by primarily genetic influences.
DOI: 10.25549/usctheses-m46
title: Cost structure and regulation in the telecommunications industry

description: Unrestricted The U.S. telecommunications industry has been the subject of many studies since the divestiture of AT&T in 1984 and the introduction of competition into long-distance. In 1996, the US government introduced the telecommunication reform (1996 Telecommunications Act) that outlines the main rules for competition in the local telephone market. But until recently, the implementation of the 96-Telecommunications Act has been problematic and under investigation. This dissertation consists of three essays, each an application of econometrics and calibration techniques to the telecommunications industry. The first essay analyzes the subadditivity and cost complementarities issue in the U.S. telecommunications industry. I use a dynamic panel data approach to estimate the total cost function of the local exchange carriers. The estimated cost function is then used in the test for subadditivity and cost complementarities. I find that the Local exchange carriers' cost appears to be subadditive meaning that breaking up the local exchange carriers is not efficient in terms of cost saving. I also find that the cost generated by jointly producing local and toll calls is on average lower than not producing them jointly. This means that we have presence of cost complementarities. The wave of merging in the telecommunication industry may be explained by the presence of cost complementarities. The second essay estimates semiparametrically the scale economies in the telecommunication industry. The semiparametric model uses the translog cost function where output enters non-parametrically. The result shows the presence of scale economies in the local exchange carrier. The scale economies seem larger for small firms compared to big firms. This result may also explain the wave of merging and consolidation that is going on in the U.S telecommunications industry. The last essay compares the different regulatory models using an engineering cost proxy function.; The method used in our study is based on generated data from a computer modeling of the local telephone network instead of the traditional approach, which focuses on real data. Using the calibration technique I find that the incentive regulation performs better compared to traditional regulation mechanisms (cost plus regulation). Following the construction of "cocomo2", a computer software cost estimation model, I also develop an alternative mapping for effort and efficiency.
DOI: 10.25549/usctheses-c3-4495
title: Characterization of cytochrome c peroxidase of Marinobacter aquaeolei

description: The molecular biology and biochemistry of biological iron oxidation at neutral pH is poorly understood.  In part this is due to the fact that most chemolithoautotrophic iron oxidizing bacteria are genetically intractable and very difficult to cultivate and manipulate in the laboratory.   The Marinobacter are ubiquitous marine bacteria that occur in hydrothermal settings, including hydrothermal plumes, chimneys, and seafloor exposed basalts.  Many are capable of iron oxidation and can also be readily cultivated and studied in the laboratory.  We hypothesize Marinobacter aquaeolei, a lithoheterotrophic iron oxidizing bacterium, utilizes the gene cytochrome c peroxidase (CCP) for Fe-oxidation during lithoheterotrophic growth. We have characterized heme protein activity during Fe-oxidation via heme staining followed by searching NCBI for genes of interest.  Our preliminary research led us to cytochrome c peroxidase, a small heme protein.  We synthetically mutated CCP, ligated the mutant into pJP5603 and then inserted it into electrocompetent Escherichia coli.  Then we conjugated the electrocompetent cells with wild-type M. aquaeolei to transfer the mutant gene.  A ferrozine assay was used to determine M. aquaeolei’s ability to oxidize iron is lost when CCP is mutated; thus our findings show CCP to be a vital component for M. aquaeolei’s ability to oxidize iron.