This project examines how middle school students engage in new literacies practices and how they repurpose across contexts. With the use of screencast software and interviews, this project analyzes six case study participants' new literacies practices and the way they use and change ideas and strategies across physical and digital contexts. Drawing from transfer methodology, this project looks at how broadening conceptions of transfer and contexts to include repurposing increases the possibilities for finding transfer in literacies practices. Applying new literacies theory, this project explores how literacies practices that are chronologically and ontologically new (Lankshear & Knobel, 2006) are often repurposed across contexts. In addition, employing rhetorical invention and arrangement theories, this project examines how contemporary invention is repurposing and how arrangement aids in meaning making in new literacies practices. It also explores concerns over increased repurposing across collapsed contexts for literacies.

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Despite decades of research aiming to ameliorate the difficulties of creating software, programming still remains an error-prone task. Much work in Computer Science deals with the problem of specification, or writing the right program, rather than the complementary problem of implementation, or writing the program right. However, many desirable software properties (such as portability) are obtained via adherence to coding standards, and therefore fall outside the remit of formal specification and automatic verification. Moreover, code inspections and manual detection of standards violations are time consuming. To address these issues, this thesis describes Exstatic, a novel framework for the static detection of coding standards violations. Unlike many other static checkers Exstatic can be used to examine code in a variety of languages, including program code, in-line documentation, markup languages and so on. This means that checkable coding standards adhered to by a particular project or institution can be handled by a single tool. Consequently, a major challenge in the design of Exstatic has been to invent a way of representing code from a variety of source languages. Therefore, this thesis describes ICODE, which is an intermediate language suitable for representing code from a number of different programming paradigms. To substantiate the claim that ICODE is a universal intermediate language, a proof strategy has been developed: for a number of different programming paradigms (imperative, declarative, etc.), a proof is constructed to show that semantics-preserving translation exists from an exemplar language (such as IMP or PCF) to ICODE. The usefulness of Exstatic has been demonstrated by the implementation of a number of static analysers for different languages. This includes a checker for technical documentation written in Javadoc which validates documents against the Sun Microsystems (now Oracle) Coding Conventions and a checker for HTML pages against a site-specifc standard. A third system is targeted at a variant of the Python language, written by the author, called python-csp, based on Hoare's Communicating Sequential Processes.

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During embryonic development neurons of the cerebral cortex are generated from various progenitor cells that have progressively restricted fate. Understanding the multiple regulatory pathways that regulate the cell cycle kinetics and the identity of neurons is crucial to comprehend the etiology of severe developmental defects such as microcephaly and polymicrogyria and also the evolutionary expansion of the mammalian cerebral cortex. Intermediate progenitors (IPCs) express the transcription factor Tbr2 (a T-box gene) and deletion of this gene causes a decrease in brain size and cortical thickness. However, little is known about the molecular mechanisms regulating behavior of IPCs. In this thesis, I studied the molecular mechanisms regulating cell division and cell fate choices in IPCs using an overexpression system. I show that Tbr2 controls the expression of key genes such as Cdk4, Aspm and Wnt5a by directly binding to upstream regulatory sequences. These downstream targets could explain the role played by Tbr2 in cell cycle, spindle assembly and Wnt signaling in intermediate progenitors. The interaction with Aspm also suggests a possible mechanism of self-renewal of IPCs leading to an expanded generation of cortical neurons and ultimately an increased cortical size. While the role of IPCs in cortical neurogenesis is undisputed, it is widely believed that they contribute only towards supragranular layers. Using a knock-in transgenic mouse line (Tbr2^Cre), I show that IPCs provide glutamatergic neurons (but not GABAergic neurons or GFAP+ astrocytes) towards all cortical layers in a significant proportion (20-40%). I also show that clonally generated neurons disperse within tangential dimension across the cortex significantly closer (142.1 ± 76.8 µm) than unrelated ones (294.9 ± 105.4 µm) though within the confines of a cortical column (300-600 µm). Finally, I describe the similarity in the germinal zones of a large-brained gyrencephalic rodent, agouti and a lissencephalic primate, marmoset. Both these species show similar germinal zone cytoarchitecture and distribution of various progenitors. Further, the number of IPCs is grossly expanded thus demonstrating the conserved role of IPCs in cortical expansion regardless of the folding status of the cortex in these two species.

published_or_final_version / Surgery / Doctoral / Doctor of Philosophy

The occurrence of large scale and rapid climate shifts at millennial time-scales (suborbital) remains an enigma between records from high and low latitudes spanning the Late Quaternary. This thesis studies such variations in the eastern tropical North Pacific (ETNP) using marine sediment cores retrieved from Mexico and Nicaragua. The main goals are to understand the nature of millennial timescale climate-changes in the Pacific low latitudes, to identify the atmospheric and oceanic teleconnections involved, to document the impacts on the biogeochemical cycles of carbon, nitrogen and silicon, and their potential to regulate Greenhouse Gas (GHG) concentrations during the last two glacial cycles (the last 240,000 years before present). In this thesis, we use a suite of multi-proxy records from the Core MD02-2519, which are compared to others records from adjoining regions to study the climatic history of the ETNP at millennial timescales. The Core MD02-2519, was retrieved from 955 mbsl off NW Mexico. It is strategically located within the North Pacific Intermediate Water (NPIW), underlying the coastal upwelling and denitrification zones of the ETNP. The paleoceanography of the region is studied using proxy records of productivity, denitrification, intermediate water circulation and radiocarbon activity, which are discussed in 5 separated chapters. In Chapter 1, we use records of organic carbon (%OC) and diffuse spectral reflectivity (DSRa*) to document changes in productivity, which are shown in phase with Northern Hemisphere (NH) timing at millennial scale, suggesting a direct atmospheric teleconnection with higher northern latitudes. In Chapter 2, reconstruction of nitrogen isotope records (δ15N) show that abrupt changes in denitrification are in phase with NH timing over the last glacial period; however, the advection of heavy nitrate from southern sources is also documented, possibly from the denitrification zone off Peru-Chile. Records of opal (%opal – Chapter 3) and carbon isotopes from benthic foraminifera (δ13C-Uvigerina – Chapter 4) support the inference of oceanic teleconnections between the ETNP and the South Pacific via subthermocline circulation. In Chapter 4, the δ13C records also suggest that intermediate water circulation changed over glacial periods and terminations, being the result of intrusion of southern component waters. In Chapter 5, the reconstruction of radiocarbon activity (Δ14C) records from surface (planktonic foraminifera) and intermediate water (benthic foraminifera) suggest oceanic degassing of old-carbon from the deep ocean during the last termination. In this way, the ETNP upwelling system could be an important locus of CO2 release at millennial timescales.

Gerald Near's Chantworks has pedagogical value for the intermediate-level organ student seeking to attain advanced-level skills. Chantworks, composed for organ solo, is a collection of twenty-three pieces of short to moderate duration, based upon Gregorian chants. Gerald Near is an established composer who has won awards, completed numerous commissions, and published a multitude of organ and choral works. The Chantworks pieces are analyzed for their usefulness in the development of the following skills: (1) the advanced use of the expression pedal; (2) advanced manual changes and registration changes; (3) voice-crossing; and (4) the ability to play Gregorian chants with rhythmic sensitivity and appropriate phrase shaping. The study highlights the particular usefulness of Near's collection by comparing its technical demands to selected organ instructional books and musical collections that have been identified as having pedagogical value. This study provides a definition of an "intermediate organist," listing techniques acquired from the successful completion of any of the selected organ pedagogy publications. An examination of selected organ pedagogy publications addresses several techniques characteristic of pipe organ performance mastery that are not emphasized in the method books, but that would be necessary for an organist to acquire in order to tackle the more difficult works of the organ literature. Musical examples and explanations will illustrate how these other techniques can be learned and practiced in a structured manner through the study of pieces from Gerald Near's Chantworks collection. Several pieces within Chantworks contain passages that have pedagogical bearing on aspects of general musicianship, such as irregular meters and cross rhythms. Appendix A includes a compilation of information about each piece within the Chantworks collection, with emphasis on each piece's compositional style, pedagogical merits, and other details worthy of analysis.