Portfolio of Electroacoustic Compositions with Commentaries

This portfolio consists of electroacoustic compositions which were primarily realised through the use of corporeally informed compositional practices. The manner in which a composer interacts with the compositional tools and musical materials at their disposal is a defining factor in the creation of musical works. Although the use of computers in the practice of electroacoustic composition has extended the range of sonic possibilities afforded to composers, it has also had a negative impact on the level of physical interaction that composers have with these musical materials. This thesis is an investigation into the use of mediation technologies with the aim of circumventing issues relating to the physical performance of electroacoustic music. This line of inquiry has led me to experiment with embedded computers, wearable technologies, and a range of various sensors. The specific tools that were used in the creation of the pieces within this portfolio are examined in detail within this thesis. I also provide commentaries and analysis of the eleven electroacoustic works which comprise this portfolio, describing the thought processes that led to their inception, the materials used in their creation, and the tools and techniques that I employed throughout the compositional process

eLearning integrators' narratives expressing professional identity and explaining patterns of practice with ICT

This research explored the complexities surrounding encouragement of the use of Information Technology (IT) in Educational settings by classroom practitioners. The Melbourne Declaration, made by all Australian Education ministers in 2008 states that successful learners 'are creative and productive users of technology, especially ICT, as a foundation for success in all learning areas'(MCEECDYA, 2008, p. 8). Early adopters of the technology encouraged their peers to embrace these new technologies with the enticing promise that it would motivate their students and make their job easier. These early adopters often became teacher leaders, given the role of eLearning Coordinator or eIntegrators (eLI’s), responsible for helping staff to integrate ICT into their classroom practices. The study investigated this role and the patterns of practice that could be identified during the investigation. This study investigated four eLI’s seeking to discover the influences on their professional duties and how their teacher identities shaped their effectiveness and influenced the decisions that they made. A Narrative Inquiry approach was used to listen to and retell their stories. This was grounded in the theories of Clandinin and Connelly (1994), borrowing particularly from their work on the commonplaces of time, place and personal-social dimensions to help focus the study and provide a lens for analysis. The methodology included in-depth interviews, observations, emails, and Skype calls to collect the data which would be used to analyse the practices and beliefs of the participants over a period of 18 months. The data analysis was done through the lens of place, temporality and personal and social commonplaces to seek understandings of the similarities and differences between the participants’ storied identities as eLI’s and their effectiveness in carrying out their duties. Results from the study confirmed a number of commonalities between the eLI’s despite their working in dissimilar environments. These commonalities included an acknowledgement that ICT’s needed to be offered as a tool to allow pedagogical change to take place and not an end in themselves. The technology also provided teachers with a vehicle to deliver content and the eLI’s used this knowledge to further encourage classroom use of IT. Administrative tasks, accreditation pressures and Executive staff leadership were all important factors in shaping the successes that the eLI’s experienced. The TPACK framework also fell within the scope of the study and among the conclusions that were reached; an expanded framework is offered in the study. The study supported the conclusion that it is a combination of the narrative commonalities that shaped the participants and their practices. The eLI was a product of their storied identity while at the same time the actions, beliefs and approaches that they took to fulfil their role added to that storied identity

North polar stratigraphy and the paleo-erg of Mars

An accurate self-consistent way of coregistering the imaging and topographic data sets of the Mars Global Surveyor mission was developed and used to begin a stratigraphic analysis of the northern polar region. A distinct change in the layering style exists at a definite stratigraphic horizon near the base of the north polar layered deposits. Occurrences of the contact between two distinct layered units can be mapped hundreds of kilometers apart at nearly the same Mars Orbiter Laser Altimeter (MOLA) elevation. The lower layered unit has a consistent association with sand dunes, leading to the conclusion that it is an eroding sand-rich deposit that predates most of the overlying north polar layered deposits, which exhibits the expected features of a dust-ice mixture. These results suggest that an areally extensive erg was in existence before the present ice cap and that the present circumpolar erg is likely composed of material reworked from this older deposit. The volume of this lower unit is estimated to be on the order of 10^5 km^3. The presence of this deposit implies that there existed a period in Mars' history when there was no icy polar cap. A dramatic climatic change leading to the deposition of the upper layered (icy) unit in the present-day polar layered deposits represents a major event in Mars' history. However, owing to uncertainties in the mechanics of layered deposits formation, such an event cannot be dated at this time

Martian climatic events on timescales of centuries: Evidence from feature morphology in the residual south polar ice cap

Flat-floored, quasi-circular depressions on the southern residual cap of Mars have been observed to expand rapidly. Analysis of the size distribution combined with modeling of the growth process yields information about the ages of these features. We report on properties of a population of these features within a selected study area. We find a narrow size distribution that indicates a common formation time and a finite period during which new features were forming. Some change in environmental conditions occurred during this period, which we date at several Martian decades to centuries ago depending on modeled growth rates. We report on THEMIS data that reveals the nature of larger features outside our study area. Underlying water ice is exposed on the flat floors of these depressions near the outer walls. These features may record more than one growth phase, indicating that conditions conducive to growth may switch on and off with characteristic timescales of Martian centuries

How DNA Packaging and Processing Proteins Affect Dynamic DNA Alkylation

DNA alkylating agents are commonly considered toxic due to the irreversible nature of the lesions that they form and the failure of DNA repair enzymes to remove their lesions. However, compounds that alkylate DNA in a reversible manner may not share the same toxicity as irreversible alkylating agents. Quinone methides (QMs) are a class of transient electrophiles that reversibly alkylate DNA. A bifunctional QM conjugated to the DNA intercalator acridine (bisQMAcr) has previously been synthesized in order to examine the dynamics of reaction with DNA. BisQMAcr’s reversible chemistry facilitates its stepwise migration from one end of a duplex DNA to the other in a bipedal manner. However, bisQMAcr requires 7 days to traverse 10 base pairs, which may be too slow to be effective in vivo to evade DNA repair. Two monofunctional QMs were linked together using a flexible polyammonium alkyl chain (diQMs) to potentially facilitate faster QM migration. Additionally, BisQMs conjugated to weakly intercalative quinoxalines were synthesized to avoid the strength of acridine’s intercalation that may have suppressed QM migration. However, neither of the new QMs alkylated DNA reversibly. Thus, bisQMAcr remains the most dynamic QM synthesized to date. The environment within cells likely influences the potency of QMs’ reversible DNA alkylation, since cellular DNA is packaged around histone proteins to form nucleosomes. The assembly of DNA into nucleosomes weakens QMs’ potency as DNA alkylating agents by 90% relative to DNA free in solution. Nucleosomes possess an additional protective function against bisQMAcr’s DNA alkylation, as the histone proteins serve as terminal acceptors of bisQMAcr’s DNA adducts. BisQMAcr can release from its adducts on DNA and alkylate the histones, leaving the DNA unmodified. However, QM alkylation of the histones does not interfere with their assembly into nucleosomes, as adducts formed in the core regions of the protein that may not disrupt with the necessary DNA-protein contacts for nucleosome formation. The ability of DNA polymerases and helicases to modulate the dynamics of bisQMAcr’s DNA alkylation and of bisQMAcr’s crosslinks to inhibit replication was also investigated to determine whether biological machines may hasten QM migration. The Klenow Exo- and φ29 DNA polymerases were unable to cause bisQMAcr’s crosslinks to break apart and failed to extend DNA primers in the presence of the crosslinks. However, the T7 bacteriophage gene 4 protein (T7GP4) DNA helicase was able to unwind DNA containing reversible QM crosslinks. The helicase induced dissociation of only 40% of bisQMAcr’s crosslinks, while the remaining 60% remained intact. Irreversible DNA crosslinks formed by mechlorethamine completely resisted unwinding by the T7GP4 helicase, suggesting that only reversible crosslinks separate during DNA unwinding. Reversible QM crosslinks may not pose an absolute block to replication like many irreversible crosslinking agents do. The ability of a helicase to remove QM adducts from DNA essentially affords DNA repair without relying on specific DNA repair proteins. This work describes the potency of reversible QM alkylation in a biological setting. Transfer of reversible adducts to the histone proteins and loss of DNA adducts by helicases’ translocation may afford their repair by means of their intrinsic reversible chemistry