Software Choices for In‑House Databases.

A number of software packages are available to help create an in-house database on a microcomputer. Because these packages vary so widely and because different programs are suited to different applications, it is useful to categorize packages by general characteristics. In-house database software can be divided into 2 broad types: 1. general purpose, which includes text retrieval, file managers, and database management systems, and 2. special purpose, which covers information storage and retrieval (IS&R) packages, integrated bibliographic systems, and library automation applications. Each type of software is appropriate in different circumstances. For example, INMAGIC and Personal Librarian, both IS&R packages selling for under $1,000, are different in strengths and weaknesses when compared together

The last common bilaterian ancestor

Many regulatory genes appear to be utilized in at least superficially similar ways in the development of particular body parts in Drosophila and in chordates. These similarities have been widely interpreted as functional homologies, producing the conventional view of the last common protostome-deuterostome ancestor (PDA) as a complex organism that possessed some of the same body parts as modern bilaterians. Here we discuss an alternative view, in which the last common PDA had a less complex body plan than is frequently conceived. This reconstruction alters expectations for Neoproterozoic fossil remains that could illustrate the pathways of bilaterian evolution

Exploring agonism with mischief: participatory performance in the public realm

This thesis explores how agonism can emerge through participatory art practice. The practice-based research is contextualised by Chantal Mouffe s political theory of agonism, and the instances in which she applies agonism to art practice (2001-2013). The research highlights the intrinsic and substantial value Mouffe s agonism holds for understanding conflict as an adversarial relation. The problem I identify is that when Mouffe applies agonism to art practice, she locates her examples within the frame of political theory, rather than in or through art practice. Consequently, this research questions agonism from the perspectives of participatory art practice, mischievous performance, and politicised dissent as relational conflict. I employ a methodology of theory and practice. Chapters One and Two expand upon Mouffe s theory of agonism, and her application of agonism to art practice. Chapters Three and Four situate the research within art theory, art history, art practice, and within mischief as a method of explaining relations of power. I expand upon the importance of participation, and I investigate how mischievous performance can facilitate the emergence of agonistic relations. In the final chapter I analyse video recordings of my practice of guerrilla street theatre. The outcome of the research is reflective analysis of evidence, and an understanding of the circumstances in which an art practice does, or does not, become agonistic. The research output is a two-fold analytical framework, and a set of criteria that can be used to clarify when and how an art practice becomes agonistic. I argue that to explore agonism through mischief facilitates (some) participants in performing their politicised dissent in the public realm. Thus, agonism as adversarial political conflict contributes to the vibrancy of the public sphere. However, by focusing on agonism and participatory art practice, I attend to the difficulties and complexities of agonistic art practices. As a result, I develop and extend Mouffe s theory of agonism through my exploration of agonism in mischievous and participatory art practice

A hazard control system for robot manipulators

A robot for space applications will be required to complete a variety of tasks in an uncertain, harsh environment. This fact presents unusual and highly difficult challenges to ensuring the safety of astronauts and keeping the equipment they depend on from becoming damaged. The systematic approach being taken to control hazards that could result from introducing robotics technology in the space environment is described. First, system safety management and engineering principles, techniques, and requirements are discussed as they relate to Shuttle payload design and operation in general. The concepts of hazard, hazard category, and hazard control, as defined by the Shuttle payload safety requirements, is explained. Next, it is shown how these general safety management and engineering principles are being implemented on an actual project. An example is presented of a hazard control system for controlling one of the hazards identified for the Development Test Flight (DTF-1) of NASA's Flight Telerobotic Servicer, a teleoperated space robot. How these schemes can be applied to terrestrial robots is discussed as well. The same software monitoring and control approach will insure the safe operation of a slave manipulator under teleoperated or autonomous control in undersea, nuclear, or manufacturing applications where the manipulator is working in the vicinity of humans or critical hardware

Analysis of the cell-specific expression of the serpent gene and its role as a cell -fate switch in Drosophila melanogaster

A universal problem in the development of complex organisms is programming totipotent cells into specialized cell types. I have focused on the Drosophila fat body and the characterization of the positional information required for the adoption of a fat cell identity by mesodermal cells. Central to this study is serpent, a transcription factor gene, both necessary and sufficient for fat-cell development; I characterized the patterns of activity for regulatory regions that control serpent expression within the fat body. The fat body is composed of three morphological domains (lateral fat body, ventral commissure, and dorsal fat cell projections) each of which requires serpent activity. Using these enhancer-regions in reporter-gene constructs, I traced the development of the dorsal fat-cell projections, the ventralmost lateral fat body, and a portion of the ventral commissure, and demonstrated that particular groups of fat-cell clusters give rise to these domains; In parallel, I determined, through mutant and misexpression genetic analysis, that the transcription factor genes, Abdominal B and tinman, are critical for serpent activation within the dorsal fat-cell cluster. Putative binding sites for these factors are present within the regulatory regions of serpent. Differing cues activate serpent in distinct embryonic regions, and I discuss the possibility that these factors are also important for the establishment of genetic differences among fat cells, and thus, functional differentiation of the fat body. Additionally, I genetically tested Ultrabithorax , another transcription factor gene with putative binding sites within one serpent-enhancer region, for its ability to regulate serpent expression. I determined that Ultabithorax is not involved in fat-cell specification, but is required for the proper morphological development of the fat body; I have also tested the proposal that within the lateral mesoderm, serpent is a cell-type switch between fat and somatic gonadal precursor cells. I find that serpent does not serve as a switch between these two cell choices. However, I provide evidence for a similar cell-fate switch, in the dorsal mesoderm, between dorsal fat cells and circular visceral muscle precursors. This switch relies on both serpent and the homeotic transcription factor, Abdominal B

Characterisation of a bagpipe homologue in Xenopus laevis

Mutations of Drosophila bagpipe, an NK3 class homeobox gene, result in failure of visceral mesoderm to differentiate into stomach tissue. Thus bagpipe, in association with other factors, is a good candidate for specification of visceral mesoderm in Drosophila. The cloning and characterisation of a Xenopus bagpipe homologue was therefore of great interest. This study describes the isolation of a full length Xenopus cDNA clone that on the basis of database analysis and sequence comparisons has been assigned as Xenopus bagpipe (XBap). Previous studies had revealed that the majority of homeoproteins recognise DNA sites with a 5'-TAAT-3' core but the NK class of homeoproteins had been shown to bind specifically to sites containing a 5'-CAAG-3' core. Experiments described here, however, show the XBap DNA binding site to be an even more divergent, 5'-TTAAGTGG-- TTAAGTGG-3'. A series of mutant oligonucleotides revealed that the `T' of the 5'- T_{1}A_{2}A_{3}G_{4}-3' core, as well as the presence of two such cores, are indeed essential for optimal XBap DNA binding. The murine NK3 class homeoproteins, Nkx-3.1 and Bapxl, are demonstrated to have the same requirements for optimal DNA binding as XBap. Drosophila Bagpipe, however, was found to have a less stringent requirement for a `T' at position one of the core, binding equally well to a 'C' in this position, but the presence of two such cores is still necessary for optimal DNA binding. Preliminary studies using site directed mutagenesis attempted to define the amino acids responsible for the differences. The effect of XBap on transcription was studied using a Xenopus oocyte assay and two cell transfection assays. XBap was not found to act as a transcriptional activator in any of these assays but evidence was obtained to suggest that a C-terminal truncation of XBap could act as a repressor of transcription

Doctor of Philosopy

dissertationGlycosaminoglycans (GAGs) are long linear polysaccharides made of disaccharide repeats. The GAGs heparan and chondroitin are found ubiquitously on cell surfaces in many organisms and are involved in regulating developmental signaling, immunity, and mediating many cell-cell interactions. In Drosophila melanogaster, GAGs are synthesized downstream of the gene mummy (mmy), which encodes the Drosophila UDP-N-acetylglucosamine pyrophosphorylase, the enzyme performing the final catalytic step in UDP-GlcNAc synthesis. mmy encodes an antagonist of Decapentaplegic (Dpp) signaling, and mmy mutant embryos have expanded ectopic Dpp activity in the dorsal epidermis. We confirmed through multiple tests that the mmy-mediated effects on Dpp signaling occur downstream of dpp transcription and that mmy activates a switch from short-range to long-range signaling in the epidermis. To identify downstream effectors of Dpp signal restriction, we screened 23 of the 25 Drosophila β-1,3-glycosyltransferases functioning downstream of Mmy. Embryos depleted of either wanderlust (wand), which encodes a putative chondroitin sulfate synthase, or super sex combs, which encodes an O-GlcNAc transferase, had Dpp activity expanded ectopically beyond the LE epidermis, identifying these transferases as a Dpp antagonists. We further characterized wand and determined that it is expressed in embryonic cardiac cells and that it antagonizes Dpp signaling in the mesoderm as well as the epidermis. Taken together, these data suggest that mmy, through wand, synthesizes a chondroitin-sulfated sink that alters the signaling range of Dpp. Future work will involve characterizing the role of other chondroitin sulfate-synthesizing genes in Drosophila signaling regulation, determining the nature of the Dpp-chondroitin interaction, exploring the role of chondroitin sulfate in imaginal disc and testes signaling, and identifying the specific GAGmodified targets that enact epidermal signal regulation. These data will provide new insights into regulation of Dpp signaling via glycosylation