6,723 research outputs found
Evaluation of live human-computer music-making: Quantitative and qualitative approaches
NOTICE: this is the author’s version of a work that was accepted for publication in International Journal of Human-Computer Studies. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in International Journal of Human-Computer Studies, [VOL 67,ISS 11(2009)] DOI: 10.1016/j.ijhcs.2009.05.00
The Serendiptichord: Reflections on the collaborative design process between artist and researcher
The Serendiptichord is a wearable instrument, resulting from a collaboration crossing fashion, technology, music and dance. This paper reflects on the collaborative process and how defining both creative and research roles for each party led to a successful creative partnership built on mutual respect and open communication. After a brief snapshot of the instrument in performance, the instrument is considered within the context of dance-driven interactive music systems followed by a discussion on the nature of the collaboration and its impact upon the design process and final piece
Optimal classical-communication-assisted local model of n-qubit Greenberger-Horne-Zeilinger correlations
We present a model, motivated by the criterion of reality put forward by
Einstein, Podolsky, and Rosen and supplemented by classical communication,
which correctly reproduces the quantum-mechanical predictions for measurements
of all products of Pauli operators on an n-qubit GHZ state (or ``cat state'').
The n-2 bits employed by our model are shown to be optimal for the allowed set
of measurements, demonstrating that the required communication overhead scales
linearly with n. We formulate a connection between the generation of the local
values utilized by our model and the stabilizer formalism, which leads us to
conjecture that a generalization of this method will shed light on the content
of the Gottesman-Knill theorem.Comment: New version - expanded and revised to address referee comment
Nonlinear Outcome of Gravitational Instability in Disks with Realistic Cooling
We consider the nonlinear outcome of gravitational instability in optically
thick disks with a realistic cooling function. We use a numerical model that is
local, razor-thin, and unmagnetized. External illumination is ignored. Cooling
is calculated from a one-zone model using analytic fits to low temperature
Rosseland mean opacities. The model has two parameters: the initial surface
density Sigma_0 and the rotation frequency Omega. We survey the parameter space
and find: (1) The disk fragments when t_c,eff Omega = 1, where t_c,eff is an
effective cooling time defined as the average internal energy of the model
divided by the average cooling rate. This is consistent with earlier results
that used a simplified cooling function. (2) The initial cooling time t_c0 or a
uniform disk with Q = 1 can differ by orders of magnitude from t_c,eff in the
nonlinear outcome. The difference is caused by sharp variations in the opacity
with temperature. The condition t_c0 Omega = 1 therefore does not necessarily
indicate where fragmentation will occur. (3) The largest difference between
t_c,eff and t_c0 is near the opacity gap, where dust is absent and hydrogen is
largely molecular. (4) In the limit of strong illumination the disk is
isothermal; we find that an isothermal version of our model fragments for Q <
1.4. Finally, we discuss some physical processes not included in our model, and
find that most are likely to make disks more susceptible to fragmentation. We
conclude that disks with t_c,eff Omega < 1 do not exist.Comment: 30 pages, 12 figure
Star Formation in Sculptor Group Dwarf Irregular Galaxies and the Nature of "Transition" Galaxies
We present new H-alpha narrow band imaging of the HII regions in eight
Sculptor Group dwarf irregular (dI) galaxies. Comparing the Sculptor Group dIs
to the Local Group dIs, we find that the Sculptor Group dIs have, on average,
lower values of SFR when normalized to either galaxy luminosity or gas mass
(although there is considerable overlap between the two samples). The
properties of ``transition'' (dSph/dIrr) galaxies in Sculptor and the Local
Group are also compared and found to be similar. The transition galaxies are
typically among the lowest luminosities of the gas rich dwarf galaxies.
Relative to the dwarf irregular galaxies, the transition galaxies are found
preferentially nearer to spiral galaxies, and are found nearer to the center of
the mass distribution in the local cloud. While most of these systems are
consistent with normal dI galaxies which currently exhibit temporarily
interrupted star formation, the observed density-morphology relationship (which
is weaker than that observed for the dwarf spheroidal galaxies) indicates that
environmental processes such as ``tidal stirring'' may play a role in causing
their lower SFRs.Comment: 35 pages, 10 figures, accepted for Feb 2003 AJ, companion to
astro-ph/021117
The evolution of stable silicon isotopes in a coastal carbonate aquifer on Rottnest Island, Western Australia
Dissolved silicon (dSi) is a key nutrient in the oceans, but data regarding Si isotopes in coastal aquifers are not widely available. Here we investigate the Si isotopic composition of 12 fresh and 16 saline groundwater samples from Rottnest Island, Western Australia, which forms part of the world's most extensive aeolianite deposit (the Tamala Limestone formation). In total, two bedrock samples were also collected from Rottnest Island for Si isotope analysis. The δ30Si values of groundwater samples ranged from −0.4 ‰ to +3.6 ‰ with an average +1.6 ‰, and the rock samples were −0.8 ‰ and −0.1 ‰. The increase in δ30Si values in fresh groundwater is attributed to the removal of the lighter Si isotopes into secondary minerals and potentially also adsorption onto Fe (oxy)hydroxides. The positive correlations between δ30Si values and dSi concentrations (ρ = 0.59; p = 0.02) and δ30Si values and Cl, but not dSi and Cl concentrations, are consistent with vertical mixing between the younger fresh groundwater and the deeper groundwater, which have undergone a greater degree of water–rock interactions. This has produced a spatial pattern in δ30Si across the aquifer due to the local hydrogeology, resulting in a correlation between δ30Si and tritium activities when considering all groundwater types (ρ = −0.68; p = 0.0002). In the deeper aquifer, the inverse correlation between dSi and Cl concentrations (ρ = −0.79; p = 0.04) for the more saline groundwater is attributed to groundwater mixing with local seawater that is depleted in dSi (< 3.6 µM). Our results from this well-constrained island aquifer system demonstrate that stable Si isotopes usefully reflect the degree of water–aquifer interactions, which is related to groundwater residence time and local hydrogeology. Our finding that lithogenic Si dissolution occurs in the freshwater lens and the freshwater–seawater transition zone on Rottnest Island appears to supports the recent inclusion of a marine–submarine groundwater discharge term in the global dSi mass balance. Geologically young carbonate aquifers, such as Rottnest Island, may be an important source of dSi in coastal regions with low riverine input and low oceanic dSi concentrations
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