University of Maryland, Baltimore County
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Making Down: A Pullman Porters Life
No full textThis thesis presents what I feel is a practical solution to a problem with interpretation at American railroad museums. In spite of a long and well documented history, African-American railroaders are often given short shrift at railroad museums, and not just enthusiast organized and administered museums but large, seemingly professional institutions. Section I of this thesis will review railroad museums, their interpretation and their visitors, as well as the broader railroad enthusiasts' community and how this community impacts railroad museum interpretation. I will use the B&O Railroad Museum in Baltimore, MD as a case study. Section II will discuss African-American railroad history with a focus on Pullman porters, their union the Brotherhood of Sleeping Car Porters and the contributions porters and union president A. Phillip Randolph made to the civil rights struggle. Section III is the performance piece, with recommendation for props, costumes and suggestions for an appropriate venue
Jacob Beser: The Forgotten Hiroshima and Nagasaki Crewmember and the Construction of Atomic Memory
No full textJacob Beser, the only man to have flown on the strike aircraft to both Hiroshima and Nagasaki, was energetically engaged in shaping the memory and interpretation of those events. As the radar countermeasures officer on the Enola Gay and Bockscar, the B-29s that dropped the bombs on Hiroshima and Nagasaki, respectively, Jacob Beser made sure that the Japanese would not interfere with the mission and ensured that both weapons detonated where and when they were intended. Two major research questions are addressed in this thesis: (1)What role did Jacob Beser play in the atomic bombings of Japan, and (2)What was his role in confronting the critics of the bombings, thus shaping American memory of that event? This paper employs first person accounts: memoirs, biographies, personal notes, interviews, and reporters' accounts, as well as various works of historians who specialize in the history of the war against Japan. It is structured in three major sections: (1) the historical debate over the use of the bombs, (2) Beser's role during the war, and (3) Beser's post-war defense of the bombings. It is clear that Jacob Beser played a crucial role in the development and delivery of the atomic bombs and ardently defended the traditional position that the atomic bombs' use was necessary to save lives and bring the war to an early end. He was a very patriotic man and a passionate defender of President Truman's decision to use the atomic bomb against Japan
Implementation of the Boolean Factoring Algorithm
No full textThe Boolean Factoring Algorithm was introduced by Lomonaco in 2013. This is an algorithm for reduction of the integer factorization problem to DNF-SAT. While DNF-SAT is in P, the reduction itself takes exponential time. This thesis expands on the variant called Multiplicative Boolean Factoring proposed in the same paper. Various optimizations are introduced and proofs for some of the results are presented. A rigorous running time analysis of the algorithms is provided. An implementation of the two algorithms was carried out in the Java programming language. Our thesis details this implementation and experimental running time analysis performed using the same. The largest number factored by our implementation so far is the 50-bit integer 1,090,093,705,635,337 in 37.67 seconds. The possibility of a sub-exponential time reduction to DNF-SAT and an extension to the discrete logarithm problem are posited as avenues for future work
Identity in Black and White: Indian Boarding School Postcards
No full textDuring the late 19th and early 20th centuries, thousands of American Indian children attended off-reservation boarding schools where administrators hoped to assimilate students into mainstream Anglo society. To achieve this goal, administrators forcefully changed the outward appearances of students while depriving them of their own languages and traditions. Postcards of these schools were sold to school curious school outsiders. This thesis examines those postcards in relation to the myriad of student experiences within the framework on an online exhibition. The exhibit argues that students found ways to shape their own experiences at the boarding schools through resistance and delicate cultural navigation. The various decisions students made while attending school impacted the evolution of personal and inter-tribal identities, transforming individuals and tribes alike. In addition, the exhibition provokes visitors to consider the tension that existed between administrator goals and the lived realities of students in the context of manufactured postcard imagery
Examining Multidecadal Relationships Between the Saharan Air Layer and Large-Scale Atlantic Hurricane Environment
No full textMassive Saharan dust outbreaks over the North Atlantic transpire in a warm and dust-laden air mass, the Saharan Air Layer (SAL), modulating oceanic and atmospheric conditions over a hurricane's main development region (MDR). Recent research suggests the SAL influences sea surface temperature (SST) variability on interannual and multidecadal time scales; however, it is unclear how distinct SAL characteristics modulate thermodynamic and kinematic fields on the same time scale and in turn, how this variation is connected to hurricane activity and tropical climate patterns. Findings from a multi-decadal (1955-2008) analysis investigating SAL character and environmental variables suggest periods of high dust (1970-90) coincide with enhanced low-level subsidence, mid-level cooling, and low-level warming and drying, all of which are unfavorable for TC development. In addition, results demonstrate during anomalously high dust years, mid-level easterly flow south of 10�N takes precedence over persistent strong mid-level westerlies
Volvox carteri: molecular evolution of RegA and related proteins, and Chromatin immunoprecipitation (ChIP) application to investigate RegA targets and modulation of hsp70A promoter chromatin
No full textResearch seeking to understand the molecular innovations involved in transitioning from unicellular to multicellular life has been limited by a lack of closely related unicellular and multicellular organisms able to serve as tractable model systems. The volvocine green algae overcome such limitations. Its members include Chlamydomonas reinhardtii (unicellular) and Volvox carteri (multicellular), which shared a common ancestor ~200 million years ago. V. carteri contains two cell types: reproductive gonidia and motile, terminally differentiated somatic cells. The regA gene product (RegA) is required for somatic cell fate and, when mutated, produces the Reg mutant phenotype. Reg mutant somatic cells develop normally during the first day of the life cycle, but dedifferentiate, then develop into gonidia. This conversion from spatial to temporal cell differentiation makes RegA an intriguing candidate for elucidating the molecular origins of one key aspect of multicellularity in the volvocine algae. Using comparative genomics, the products of regA and regA-like (rls) genes were found to contain a putative DNA-binding domain (VARL, for Volvocine-Algal-RegA-Like), also encoded by several C. reinhardtii genes. This dissertation addresses the evolutionary origins of RegA structure and function, as well as its role as a putative transcription factor. Using Rt-PCR I discovered that the rlsA, rlsE, rlsF, and rlsH mRNAs are spliced to produce VARL-domain proteins; however, rlsC and rlsG mRNAs are not. To address a possible role for RegA as a transcription factor, I generated a plasmid encoding a GFP-RegA fusion, which rescued regA loss of function mutants. I then optimized a Chromatin Immunoprecipitation (ChIP) platform for use in V. carteri, and validated ChIP by examining histone occupancy at the hsp70A promoter. I discovered that heat shock decreases unmodified histone H3 occupancy; increases relative H3k4me1, H3K14ac and pan-acetylated histone H4 levels; but has no effect on the relative H3K4me3 levels. I used ChIP, followed by massively parallel sequencing (ChIP-Seq), to identify DNA targets of RegA. No statistically significant sequences were identified, but non-statistically significant enrichment was detected at the promoter and eleventh intron of the retinoblastoma-related 1 (rbr1) gene. I confirmed enrichment by ChIP-qPCR, suggesting that RegA might regulate rbr1 during somatic cell terminal differentiation
Competition, Choice and Mating Success in the Darter Subgenus Catonotus
No full textMate choice and competition for mates can strongly influence fitness. Selection to compete within a sex varies with the operational sex ratio (OSR), the ratio of fertilizable females to males, with the more abundant sex being more competitive. In animals, males often appear to be the more competitive sex, as indicated by conspicuous male-male aggression, solicitation of females, and/or secondary sexual ornaments, such as the bright male nuptial coloration of most species of the darter genus Etheostoma. Species with paternal care, however, have male nuptial coloration that is less conspicuous to the human eye. In some fishes and birds with substantial paternal care, females are the more competitive sex, and males are choosier. In the first chapter, I investigate whether this pattern holds in the paternal care darter E. nigripinne by offering males and females a choice between either a conspecific or heterospecific mate. Females strongly preferred conspecific mates, while males showed no group-wide preference. In the second chapter, I examine life history characteristics in a local population of another paternal care darter, E. flabellare, to quantify the OSR experienced by reproductively active individuals. Results indicated that the OSR varies seasonally in this species, which may select for flexible levels of competitiveness and choosiness. To test whether such behavioral flexibility exists, in the third chapter I observed the competitive and solicitous behaviors of nine cohorts of males and females under manipulated OSRs over the course of two mating seasons. Male competitive behavior increased, and female competitiveness decreased, with the addition of more males. In the fourth chapter, I tested whether the observed changes in male behavior yielded increased reproductive success. Indeed, increased male-male aggression predicted increased male fitness. I conclude that male E. flabellare respond plastically and adaptively to OSR variance in a manner predicted by sexual selection theory
CHEMOENZYMATIC SYNTHESIS OF HOMOGENEOUS GLYCOPEPTIDES AND GLYCOPROTEINS FOR FUNCTIONAL STUDIES
No full textFunctional and structural studies on glycoproteins are hampered by lack of homogeneous structures due to the inherent structural heterogeneity in the pendant glycans which makes separation by routine chromatographic techniques extremely difficult. To address this problem, we used a chemoenzymatic method to make homogeneous glycopeptides and glycoproteins, which relies on the glycosynthase-based transglycosylation of a GlcNAc-peptide/protein using synthetic glycan oxazoline as the enzyme substrate. The thesis research presented here consists of three projects. First, we synthesized selectively fluorinated homogeneous Man3GlcNAc2-RNase glycoproteins for binding studies to the concanavalin A (con A) lectin. From SPR analysis, we observed that fluorine substitution at the C6-hydroxyl of the α-1,6-branched mannose residue of the Man3GlcNAc2 negated lectin binding suggesting the importance of that hydroxyl group in binding interactions. We found that the fluorinated glycan oxazoline corresponding to the Man3GlcNAc core could serve as an excellent substrate for the Endo-A enzyme during transglycosylation and a structural modeling analysis of the Endo-A enzyme binding pocket suggested favorable hydrophobic interactions between a suitably located tyrosine and the fluorine. This suggest that the selectively fluorinated glycoproteins can be used to probe specific protein-carbohydrate interactions. Secondly, we synthesized homogeneous HIV-1 V3 glycopeptides for characterizing the epitope of a recently discovered, potent anti-HIV-1 broadly neutralizing antibody (bnAb) PGT121 and related antibody 1074. SPR binding analysis indicated that antibody PGT121 recognizes complex type N-glycan while the PGT121-like antibody 10-1074 binds to high-mannose type N-glycan (Man9GlcNAc2) in the context of the V3 domain. Interestingly, these antibodies did not bind to free N-glycans or non-glycosylated V3 polypeptides under the same conditions. This study has facilitated the characterization of the glycan specificity of the two anti-HIV antibodies. Finally, we designed and synthesized a novel multifunctional BALT tag for separation of N-glycans for functional glycomics applications. It consists of an N-methylhydroxylamine group for attachment to reducing ends of glycans with preservation of ring structure, free primary amine for immobilization to microarrays, tyrosine group providing a chromophore and hydrophobicity during chromatographic separation and biotin for binding to streptavidin. The tag was successfully used for separation and recovery of individual N-glycans from a mixture of four N-glycans released from the glycoprotein bovine fetuin
The Culture Problem in Intercultural Communication: Toward a Critical Proficiency of Power
No full textIntercultural Communication (INCC) is dominated by a simple conception of culture that has, in essence, led its research and literature away from attending to relations of power in intercultural relationships. INCC's traditional approach based on positivistic and static notions of culture are rather anemic in their own right but also too brittle to support the lived experiences of globalization. One negative consequence of this faulty theoretical framework is in applied INCC, intercultural communication training, which seems to have influence across disciplinary lines, specifically in teacher training programs. Therefore, in this dissertation, I offer a close examination of the culture problem in the theoretical framework of INCC and propose Bourdieu's critical social theories as an alternative approach to studying intercultural relationships. Bourdieu's conceptions of the field of power, field of opinion, symbolic capital, and habitus offer a productive means of approaching culture more critically as it situates all social interactions, of which intercultural interactions are a subset, in dynamic fields of power that have the explanatory capability to carefully attend to the relations of power at work in these social interactions. I then offer an example of how Bourdieu's theories bear out in practice when they are applied to an intercultural training program in a master's level class for pre-service ESOL (English for Speakers of Other Languages) teachers
