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Biodiversity of arthropods living in dead wood is often understudied despite their potential effects on ecological processes such as wood decomposition and nutrient cycling. More time-efficient and less destructive methods are needed to study these saproxylic organisms to fully understand their global diversity. Because ecoacoustic methods have never been applied to saproxylic communities before, field and analytical methods such as waveguides, and soundproofing were developed, tested, and optimized. After developed methods were implemented in the field, Pearson's correlation tests were conducted to compare ecoacoustic index performance to traditional biodiversity indices. We found five significant correlations, all of which occurred at our Mississippi site, and all but one of which were negative correlations. Ecoacoustic indices performed best when correlated with order richness. Significance present in our study shows potential for ecoacoustics as a non-destructive method to study saproxylic arthropods, but methods still have room for improvement to optimize field application.

<p> The extensive;: use of antibiotics in the clinic, veterinary medicine, and agricultures has imposed an immense selective pressure for the emergence of antibiotic resistant bacteria In order to maintain the upper hand against pathogenic bacteria, we must constantly seek new antimicrobials. Most antibiotics used in the clinic were discovered as natural products or are derivatives thereof. Therefore, we must seek means of increasing the chemical diversity of natural products in our quest for new antibiotics. Herein, we investigate methyltransferases as agents to increase chemical diversity. More specificity, we have performed biochemical studies on a tetracycline and a glycopeptide methyltransferase. </p> <p> In our studies of the putative tetracycline N-methyltransferase OxyT, we determined the conditions required to overexpress the protein in an E. coli host. Subsequently, using purified protein we examined substrate specificity using commercially available compounds. However, we were unable to detect methylation of the compounds tested and therefore we made an effort to secure a biologically relevant substrate by insertionally inactivating the oxyT gene in S. rimosus but were unsuccessful. </p> <p> In our studies of the glycopeptide N-methyltransferase MtfA, we examined the biochemical activity of this enzyme on the glycopeptide desulfo-A47934. We purified desulfo-A47934 as a fermentation product of S. toyocaensis ΔstaL and determined an extinction co-efficient of 4200 Lmol^-1cm^-1. Furthermore, based on a crystal structure of MtfA we biochemically characterized the enzyme and its four mutants Y32F, E144A, H228A, and R230A to study residues involved in substrate binding and catalysis. We demonstrated that these mutations did not alter quaternary protein structure but did lead to a significant decrease in enzyme activity as compared to the wild-type enzyme. </p> / Thesis / Master of Science (MSc)

This dissertation reports results of an investigation into the performance of adaptive beamforming and diversity combining using antenna arrays that can be mounted on handheld radios. Handheld arrays show great promise for improving the coverage, capacity, and power efficiency of wireless communication systems. Diversity experiments using a handheld antenna array testbed (HAAT) are reported here. These experiments indicate that signals received by the antennas in two-element handheld antenna arrays with spacing of 0.15 wavelength or greater can be combined to provide 7-9 dB diversity gain against fading at the 99% reliability level in non line-of-sight multipath channels. Thus, peer-to-peer systems of handheld transceivers that use antenna arrays can achieve reliability comparable to systems of single-antenna handheld units, with only one-fifth the transmitter power, resulting in lower overall power consumption and increased battery life. Similar gains were observed for spatial, polarization, and pattern diversity. Adaptive beamforming with single- and multi-polarized four-element arrays of closely spaced elements was investigated by experiment using the HAAT, and by computer simulation using a polarization-sensitive vector multipath propagation simulator developed for this purpose. Small and handheld adaptive arrays were shown to provide 25 to 40 dB or more of interference rejection in the presence of a single interferer in rural, suburban, and urban channels including line-of-sight and non line-of-sight cases. In multipath channels, these performance levels were achieved even when there was no separation between the transmitters in azimuth angle as seen from the receiver, and no difference in the orientations of the two transmitting antennas. This interference rejection capability potentially allows two separate spatial channels to coexist in the same time/frequency channel, doubling system capacity. / Ph. D.

This dissertation presents an integrated framework that was developed to examine trajectories of neighborhood change, mechanisms of suburban diversity, and the relationships between neighborhood change and employment accessibility. First, this dissertation extends the study of neighborhood change to a greater time and spatial span, systematically examining the trajectories of neighborhood change at the census tract level. The results show that neighborhood change is complicated and exhibits various trajectories. The dominant patterns do not always conform to classical models of neighborhood change, providing counterpoints to some long-established assumptions. This dissertation also provides evidence of the mechanisms through which metropolitan and suburban characteristics influence suburban diversity. Most importantly, it highlights a remarkable increase in suburban diversity with respect to neighborhood composition. Finally, this dissertation investigates the relationships between neighborhood change, spatial transformation, and employment accessibility in the North Carolina Piedmont region during the last three decades. Spatial patterns of the neighborhood distributions suggest that job accessibility varies by neighborhood typology. A detailed analysis of the trajectories of neighborhood change shows interesting patterns in both central city and suburban ecological succession and transformation. These geographical shifts of neighborhoods were shown to be associated with changes in job accessibility to a certain extent. In sum, by introducing an integrated framework including social, spatial, and employment factors, this dissertation develops a more balanced understanding of neighborhood change in the United States. / Ph. D.

In response to the student retention and diversity issues that have been persistent in undergraduate engineering education, many colleges have developed Engineering Student Support Centers (ESSCs) such as Minority Engineering Programs (MEPs) and Women in Engineering Programs (WEPs). ESSCs provide underrepresented students with co-curricular support using student interventions in the form of programs, activities, and services. However, ESSCs have a relatively short history and there are gaps in our knowledge about these support systems. While the practice of providing students with co-curricular support has been evaluated, theories of co-curricular support have not been as thoroughly investigated; we know very little about how co-curricular support functions alongside engineering curricula. In an effort to help close the gaps in current literature, the purpose of my study was to explore how the student interventions offered alongside engineering curricula influence the undergraduate experience. To address this purpose, I used a multi-case study design to explore the particulars of six ESSCs housed at four institutions. I focused on the ESSC administrators (those who provide support) and undergraduate students (those who receive support) using multiple qualitative data collection methods. The primary result of this study was the Model of Co-curricular Support (MCCS), which is a version of Tinto's Model of Institutional Departure that I repurposed to demonstrate the breadth of co-curricular assistance required to comprehensively support undergraduate engineering students. The MCCS illustrates how a student's interaction with the academic, social, and professional systems within a college–as well as the university system surrounding the college–could influence the success he or she has in an undergraduate engineering program. More specifically, the MCCS is a conceptual model for constructing and evaluating support systems and individual student interventions that prioritize undergraduate engineering students. Within my study, I also identified several classifications of ESSCs and highlighted some pros and cons associated with various classifications and configurations. Ultimately, this research combines student-retention theory with student-support practice in a way that could facilitate future collaborations among educational researchers and student-support practitioners. / Ph. D.

Suburban housing is a building type and form of development that has been neglected by many architects. Architects are responsible for designing only two percent of suburban residences. This means that the profession has largely ceded the best opportunity to be relevant and useful to ordinary people. The name itself, sub-urban, implies that the suburbs are less than or secondary to the urban typology. Suburban can also be used as an adjective to describe something which is dull and ordinary. And yet, more and more people continue to move to the suburbs each year. Since 1970, a greater percentage of the population has lived in the suburbs than in central cities or rural areas. This thesis examines why people want to live in the suburbs and the impact of suburban development on the economy, the environment and social institutions. The conclusions of this investigation are then used to redefine the current concept of suburbia as it relates to nature, community and diversity. These concepts are in turn incorporated into a prototype for a suburban housing development. The prototype is a 38 unit residential housing development on a 2-acre wooded site in a suburb 16 miles west of Washington, DC. / Master of Architecture / Suburban housing is a building type and form of development that has been neglected by many architects. Architects are responsible for designing only two percent of suburban residences. This means that the profession has largely ceded the best opportunity to be relevant and useful to ordinary people. The name itself, sub-urban, implies that the suburbs are less than or secondary to the urban typology. Suburban can also be used as an adjective to describe something which is dull and ordinary. And yet, more and more people continue to move to the suburbs each year. Since 1970, a greater percentage of the population has lived in the suburbs than in central cities or rural areas. This thesis examines why people want to live in the suburbs and the impact of suburban development on the economy, the environment and social institutions. The conclusions of this investigation are then used to redefine the current concept of suburbia as it relates to nature, community and diversity. These concepts are in turn incorporated into a prototype for a suburban housing development. The prototype is a 38 unit residential housing development on a 2-acre wooded site in a suburb 16 miles west of Washington, DC.

Few studies have evaluated the community dynamics of pest ant species in tropical urban environments. Pest ant community dynamics were examined within three Puerto Rican housing developments. Housing developments (one, four, and eight years old), representing different stages of urban succession were sampled to determine which species were present and the relative species abundance. Eight trips were made to Puerto Rico over a one-year period, and more than 1,000 samples were collected during each trip. The ants collected in each sample were counted and identified. A total of 25 different species were identified from the developments, with the major pest species being big-headed, rover, and red imported fire ants (RIFA). Fourteen different species were identified from the one-year-old site. However, RIFA and rover ants were the most abundant, accounting for >75% of ants collected. In the four-year-old site, 20 species were identified. However, three species (RIFA, big-headed, and destructive trailing ants) were dominant, accounting for >75% of ants collected. Sampling data from the eight-year-old site indicated that out of 21 species identified, four species were dominant (RIFA, crazy, and two species of big-headed ants) and accounted for >75% of the ants collected. The dominant species within each site were different, indicating that the pest ant community changed during the stages of succession. However, these dominant species did not specifically impact the distribution of other species within the same site. Spatial analysis indicated that the number of species coexisting within a site increased as the age of the development increased. / Master of Science in Life Sciences

A total of 42,500 cases of autism are estimated to exist in Saudi Arabia. Many children displaying signs of autism spectrum disorder are concealed by their parents, resulting in an undiagnosed condition due to parental concealment. Many parents are concerned that their child will be stigmatized if others discover he or she has autism. Saudi Arabian culture does not display any signs of autism. Children who are displaying signs of autism spectrum disorder are often hidden by their parents, leading to undiagnosed cases of autism spectrum disorder. In Saudi Arabia, specifically in Riyadh, you will not find any autistic children or adults. Parents are concerned about the negative social consequences of others learning that their child has autism. They typically hide autistic children in separate rooms even when visiting other people's homes. In a study conducted by the American Psychological Association, 37.7% of families report being embarrassed by their autistic child. Further, 63.9% report experiencing difficulties because of society's treatment of autistic people. According to the study, 31.1% of areas do not have autism centers. A number of parks, schools, and malls are currently being constructed in the Al-Hamra neighborhood in Riyadh, the capital of Saudi Arabia. This facility will provide neighborhood residents with a safe, supportive, and socially aware environment. It will provide a portion of land near Prince Abdulaziz Bin Mohammed Park. It is crucial to establish a place where neurodivergent people can study, relax, and interact in a social setting. This will break down the stigma associated with neurodivergent people. This will create an open and accepting atmosphere, which will allow neurodivergent people to develop their skills and engage in meaningful activities while feeling safe and secure. This will be beneficial to not only the neurodivergent people but also to the whole community that will benefit from their inclusion. / Master of Architecture / A total of 42,500 cases of autism are estimated to exist in Saudi Arabia. Many children displaying signs of autism spectrum disorder are concealed by their parents, resulting in an undiagnosed condition due to parental concealment. Many parents are concerned that their child will be stigmatized if others discover he or she has autism. Saudi Arabian culture does not display any signs of autism. Children who are displaying signs of autism spectrum disorder are often hidden by their parents, leading to undiagnosed cases of autism spectrum disorder. In Saudi Arabia, specifically in Riyadh, you will not find any autistic children or adults. Parents are concerned about the negative social consequences of others learning that their child has autism. They typically hide autistic children in separate rooms even when visiting other people's homes. In a study conducted by the American Psychological Association, 37.7% of families report being embarrassed by their autistic child. Further, 63.9% report experiencing difficulties because of society's treatment of autistic people. According to the study, 31.1% of areas do not have autism centers. A number of parks, schools, and malls are currently being constructed in the Al-Hamra neighborhood in Riyadh, the capital of Saudi Arabia. This facility will provide neighborhood residents with a safe, supportive, and socially aware environment. It will provide a portion of land near Prince Abdulaziz Bin Mohammed Park. It is crucial to establish a place where neurodivergent people can study, relax, and interact in a social setting. This will break down the stigma associated with neurodivergent people. This will create an open and accepting atmosphere, which will allow neurodivergent people to develop their skills and engage in meaningful activities while feeling safe and secure. This will be beneficial to not only the neurodivergent people but also to the whole community that will benefit from their inclusion.

International Telemetering Conference Proceedings / October 28-31, 1996 / Town and Country Hotel and Convention Center, San Diego, California / The tracking system is part of a telemetry ground station being developed for the UK Ministry of Defence. The design objective is a self-contained transportable system for field use in a vehicle or workshop environment, so that the system components are required to be man portable. Comprehensive facilities are required for the reception, display and analysis of telemetry data from a remote 1430-1450MHz airborne source at ranges of up to 205km. Since tracking over water is a prime requirement the system must accommodate severe multipath fading. A detailed analysis of the link budget indicates that there is a major conflict between cost, portability, antenna size and the receiver complexity required to achieve a satisfactory performance margin. A baseline system is analysed using a four foot antenna. Methods for improving the performance are then considered including polarisation, frequency and space diversity coupled with alternative antenna types and configurations. The optimum solution utilises two six foot diameter shaped beam single axis antennas of unique design in conjunction with a receiving system which economically combines the elements of polarisation, frequency and space diversity.