94 research outputs found

    Interaction Design for Digital Musical Instruments

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    The thesis aims to elucidate the process of designing interactive systems for musical performance that combine software and hardware in an intuitive and elegant fashion. The original contribution to knowledge consists of: (1) a critical assessment of recent trends in digital musical instrument design, (2) a descriptive model of interaction design for the digital musician and (3) a highly customisable multi-touch performance system that was designed in accordance with the model. Digital musical instruments are composed of a separate control interface and a sound generation system that exchange information. When designing the way in which a digital musical instrument responds to the actions of a performer, we are creating a layer of interactive behaviour that is abstracted from the physical controls. Often, the structure of this layer depends heavily upon: 1. The accepted design conventions of the hardware in use 2. Established musical systems, acoustic or digital 3. The physical configuration of the hardware devices and the grouping of controls that such configuration suggests This thesis proposes an alternate way to approach the design of digital musical instrument behaviour – examining the implicit characteristics of its composite devices. When we separate the conversational ability of a particular sensor type from its hardware body, we can look in a new way at the actual communication tools at the heart of the device. We can subsequently combine these separate pieces using a series of generic interaction strategies in order to create rich interactive experiences that are not immediately obvious or directly inspired by the physical properties of the hardware. This research ultimately aims to enhance and clarify the existing toolkit of interaction design for the digital musician

    DroneUnknown: An experiment in embracing unpredictability in live electronic performance

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    DroneUnknown aims to explore this ambiguous space by capitalising on the unpredictability of selfmodifying instruments, rather thantrying to restrain it. The program runs on intunative (the author's own multitouch performance platform formerly known as Oscar) and draws random source material from a bank of samples at initialisationtime. The player must navigate through the material live during performance and discover it as the audience does. This leads to a manmachine duel with a number of possible approaches, ranging from a tentative exploration of the programs state to much more aggressive journeys

    Time-dependent Hartree-Fock study of quasifission trajectories in reactions forming 294^{294}Og

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    Background: Fission modes in superheavy nuclei are expected to be impacted by quantum shell effects. Similar shell effects may be present in quasifission reactions, acting to hinder the mass equilibration process in heavy-ion collisions. Purpose: To investigate quasifission mechanisms in five different reactions forming 294^{294}Og as a compound nucleus and compare quasifission trajectories with predicted fission modes. Methods: The potential energy surface (PES) of 294^{294}Og is calculated using the static Hartree-Fock approach with BCS pairing correlations. Quasifission trajectories for central collisions at various energies are studied with the time-dependent Hartree-Fock theory. Results: The exit channel strongly depends on initial mass asymmetry and orientation, but it only exhibits small dependences in the reaction energy. The 48^{48}Ca+246+^{246}Cf reaction is affected by the PES topology, leading to either fusion or asymmetric fission. Spherical shell effects associated with the Z=50Z=50 magic gap hinder charge and mass equilibrations in 126^{126}Sn+168+^{168}Er, resulting in large total kinetic energies and compact scission configurations. Conclusions: Quasifission trajectories can be interpreted in terms of the underlying PES for low excitation energies. Future investigations of quasifission with temperature and angular momentum dependent PES could be considered.Comment: 14 pages, 11 figures, 6 table

    Dellafossite CuAlO2 film growth and conversion to Cu–Al2O3 metal ceramic composite via control of annealing atmospheres

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    In this work we demonstrate simple techniques to form well crystallised CuAlO2 powders and thick films from CuO and boehmite or alumina, using a novel molten salt painting process. We examine the formation mechanism using X-ray diffraction, scanning electron microscopy, energy dispersive X-ray 15 spectroscopy and in situ high temperature X-ray diffraction and find that the annealing atmosphere plays a critical role. From this we develop a method to create Cu-Al2O3 conductive metal-ceramic composite materials with novel morphologies via the thermal decomposition of CuAlO2 precursor films

    Spatially resolved investigation of the optical and structural properties of CuCl thin films on Si

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    CuCl thin films grown on (100) Si by thermal evaporation are studied by means of low temperature photoluminescence (PL) and reflectance spectroscopies. Spatially and wavelength resolved room temperature cathodoluminescence (CL) imaging of the surface of the CuCl samples in a scanning electron microscope (SEM) has also been performed. The reflectance spectra are modeled using a dielectric response function with various models involving dead layers and reflected waves in the thin film and the exciton-polariton structure obtained is compared to other studies of CuCl. The modeling is shown to match the experimental data quite well when a dead layer is included at the air/CuCl and CuCl/Si interfaces. Some inconsistencies between the CL spectra and those measured by PL and reflectance have been observed. The effects of changing the accelerating voltage of the probe from 10 keV to the range 1-5 keV to allow depth analysis of the CL are reported, in order to pinpoint the spatial origin of the CL emission within the thin film

    Evolution of Phototrophy in the Chloroflexi Phylum Driven by Horizontal Gene Transfer

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    The evolutionary mechanisms behind the extant distribution of photosynthesis is a point of substantial contention. Hypotheses range from the presence of phototrophy in the last universal common ancestor and massive gene loss in most lineages, to a later origin in Cyanobacteria followed by extensive horizontal gene transfer into the extant phototrophic clades, with intermediate scenarios that incorporate aspects of both end-members. Here, we report draft genomes of 11 Chloroflexi: the phototrophic Chloroflexia isolate Kouleothrix aurantiaca as well as 10 genome bins recovered from metagenomic sequencing of microbial mats found in Japanese hot springs. Two of these metagenome bins encode photrophic reaction centers and several of these bins form a metabolically diverse, monophyletic clade sister to the Anaerolineae class that we term Candidatus Thermofonsia. Comparisons of organismal (based on conserved ribosomal) and phototrophy (reaction center and bacteriochlorophyll synthesis) protein phylogenies throughout the Chloroflexi demonstrate that two new lineages acquired phototrophy independently via horizontal gene transfer (HGT) from different ancestral donors within the classically phototrophic Chloroflexia class. These results illustrate a complex history of phototrophy within this group, with metabolic innovation tied to HGT. These observations do not support simple hypotheses for the evolution of photosynthesis that require massive character loss from many clades; rather, HGT appears to be the defining mechanic for the distribution of phototrophy in many of the extant clades in which it appears

    Mortality in pediatric oncology and stem cell transplant patients with bloodstream infections

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    BACKGROUND: Bloodstream infections (BSI) continue to represent a significant source of morbidity for pediatric oncology patients, however less is known regarding this population\u27s risk of death. We sought to evaluate the risk of BSI and death at a large pediatric cancer center. METHODS: We retrospectively collected inpatient data from pediatric oncology and hematopoietic stem cell transplant (HSCT) patients over a 9-year period. We performed univariate and multivariable modeling to assess risk of BSI and mortality examining the following variables: demographics, underlying malignancy, history of HSCT, central line type, and febrile neutropenia (FN). RESULTS: During the study period, 6763 admissions from 952 patients met inclusion criteria. BSI occurred in 367 admissions (5.4%) from 231 unique individuals. Risk factors for BSI include younger age, diagnoses of hemophagocytic lymphohistiocytosis or acute myeloid leukemia, ethnicity, and history of HSCT. Mortality for those with BSI was 6.5%, compared to 0.7% without (OR 7.2, CI 4.1 - 12.7, p\u3c0.0001). In patients with BSI, admissions with FN were associated with reduced mortality compared to admissions without FN (OR 0.21, CI 0.05 - 0.94, p=0.04). In both univariate and multivariable analysis, no other risk factor was significantly associated with mortality in patients with BSI. CONCLUSION: BSI is a significant source of mortality in pediatric oncology and HSCT patients. While demographic variables contribute to the risk of BSI, they did not influence mortality. These findings highlight the importance of BSI prevention to reduce the risk of death in pediatric oncology patients. Future studies should focus on comprehensive BSI prevention

    Low temperature growth technique for nanocrystalline cuprous oxide thin films using microwave plasma oxidation of copper

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    We report on the direct formation of phase pure nanocrystalline cuprous oxide (Cu2O) film with band gap ~ 2 eV by microwave plasma oxidation of pulsed dc magnetron sputtered Cu films and the highly controlled oxidation of Cu in to Cu2O and CuO phases by controlling the plasma exposure time. The structural, morphological and optoelectronic properties of the films were investigated. p-type Cu2O film with a grain size ~20-30 nm, resistivity of ~66 Ω cm and a hole concentration of ~2×1017 cm-3 is obtained for a plasma exposure time of 10 min without using any foreign dopants. The optical absorption coefficient (~105 cm-1) of the Cu2O film is also reported

    Phototrophic Methane Oxidation in a Member of the Chloroflexi Phylum

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    Biological methane cycling plays an important role in Earth's climate and the global carbon cycle, with biological methane oxidation (methanotrophy) modulating methane release from numerous environments including soils, sediments, and water columns. Methanotrophy is typically coupled to aerobic respiration or anaerobically via the reduction of sulfate, nitrate, or metal oxides, and while the possibility of coupling methane oxidation to phototrophy (photomethanotrophy) has been proposed, no organism has ever been described that is capable of this metabolism. Here we described a new bacterial genome from a member of the Chloroflexi phylum--termed here Candidatus Chlorolinea photomethanotrophicum--with cooccurring methanotrophy and phototrophy pathways, suggesting a novel link between these two metabolisms. Recovered as a metagenome-assembled genome from microbial mats in an iron-rich hot spring in Japan, Ca. "C. photomethanotrophicum" forms a new lineage within the Chloroflexi phylum and expands the known metabolic diversity of this already diverse clade. Ca. "C. photomethanotrophicum" appears to be metabolically versatile, capable of phototrophy (via a Type 2 reaction center), aerobic respiration, nitrite reduction, oxidation of methane and carbon monoxide, and potentially carbon fixation via a novel pathway composed of hybridized components of the serine cycle and the 3-hydroxypropionate bicycle. The biochemical network of this organism is constructed from components from multiple organisms and pathways, further demonstrating the modular nature of metabolic machinery and the ecological and evolutionary importance of horizontal gene transfer in the establishment of novel pathways
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