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Non-invasive imaging of subsurface paint layers with optical coherence tomography
Optical coherence tomography (OCT) systems are fast scanning infrared Michelson interferometers designed for the non-invasive examination of the interiors of the eye and subsurface structures of biological tissues. OCT has recently been applied to the non-invasive examinations of the stratigraphy of paintings and museum artefacts. So far this is the only technique capable of imaging non-invasively the subsurface structure of paintings and painted objects. Unlike the traditional method of paint cross-section examination where sampling is required, the non-invasive and non-contact nature of the technique enables the examination of the paint cross-section anywhere on a painting, as there is no longer an issue with conservation ethics regarding the taking of samples from historical artefacts. A range of applications of the technique including the imaging of stratigraphy of paintings and painted artefacts, the imaging of underdrawings to the analysis of the optical properties of paint and varnish layers is presented. Future projects on the application of OCT to art conservation are discussed
Adapted digital music players for individuals with severe impairments
This is the peer reviewed version of the following article: Saunders, M. D., Questad, K. A., Cullinan, T. B., & Saunders, R. R. (2011). Adapted Digital Music Players for Individuals with Severe Impairments. Behavioral InterventionsâŻ: Theory & Practice in Residential & Community-Based Clinical Programs, 26(2), 10.1002/bin.327. http://doi.org/10.1002/bin.327, which has been published in final form at doi.org/10.1002/bin.327. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-ArchivingPortable music production devices, such as radios, cassette players and MP3 players have characteristics that make them less than ideal for teaching the cause-and-effect relationships that would enable children and adults with severe impairments to control them independently and appropriately. Even when adapted for control with adaptive switches, the relationship between switch closure and on-off operation results in contingency characteristics that can inhibit learning. Some solutions to these problems are described, and for those individuals who can learn with complex contingencies, some promising products are reviewed
Southern Sky Redshift Survey: Clustering of Local Galaxies
We use the two-point correlation function to calculate the clustering
properties of the recently completed SSRS2 survey. The redshift space
correlation function for the magnitude-limited SSRS2 is given by xi(s)=(s/5.85
h-1 Mpc)^{-1.60} for separations between 2 < s < 11 h-1 Mpc, while our best
estimate for the real space correlation function is xi(r) = (r/5.36 h-1
Mpc)^{-1.86}. Both are comparable to previous measurements using surveys of
optical galaxies over much larger and independent volumes. By comparing the
correlation function calculated in redshift and real space we find that the
redshift distortion on intermediate scales is small. This result implies that
the observed redshift-space distribution of galaxies is close to that in real
space, and that beta = Omega^{0.6}/b < 1, where Omega is the cosmological
density parameter and b is the linear biasing factor for optical galaxies. We
also use the SSRS2 to study the dependence of xi on the internal properties of
galaxies. We confirm earlier results that luminous galaxies (L>L*) are more
clustered than sub-L* galaxies and that the luminosity segregation is
scale-independent. We find that early types are more clustered than late types,
but that in the absence of rich clusters, the relative bias between early and
late types in real space, is not as strong as previously estimated.
Furthermore, both morphologies present a luminosity-dependent bias, with the
early types showing a slightly stronger dependence on luminosity. We also find
that red galaxies are significantly more clustered than blue ones, with a mean
relative bias stronger than that seen for morphology. Finally, we find that the
relative bias between optical and iras galaxies in real space is b_o/b_I
1.4.Comment: 43 pages, uses AASTeX 4.0 macros. Includes 8 tables and 16 Postscript
figures, updated reference
The IRAS 1-Jy Survey of Ultraluminous Infrared Galaxies: I. The sample and Luminosity Function
A complete flux-limited sample of 118 ultraluminous infrared galaxies (ULIGs)
has been identified from the IRAS Faint Source Catalog (FSC). The selection
criteria were a 60 micron flux density greater than 1 Jy in a region of the sky
delta > -40 deg, |b| > 30 deg. All sources were subsequently reprocessed using
coadded IRAS maps in order to obtain the best available flux estimates in all
four IRAS wavelength bands. The maximum observed infrared luminosity is L_ir =
10^{12.90} L_{sun}, and the maximum redshift is z = 0.268. The luminosity
function for ULIGs over the decade luminosity range L_ir = 10^{12} - 10^{13}
L_{sun} can be approximated by a power law Phi (L) ~= L^{-2.35} Mpc^{-3}
mag^{-1}. In the local Universe z < 0.1, the space density of ULIGs appears to
be comparable to or slightly larger than that of optically selected QSOs at
comparable bolometric luminosities. A maximum likelihood test suggests strong
evolution for our sample; assuming density evolution proportional to
(1+z)^{alpha} we find alpha = 7.6+/-3.2. Examination of the two-point
correlation function shows a barely significant level of clustering, xi (r) =
1.6 +/- 1.2, on size scales r ~= 22 h^{-1} Mpc.Comment: 18 pages of text, 10 pages of figures 1 to 6, 6 pages of tables 1 to
3, ApJS accepte
Negative oxygen vacancies in HfO as charge traps in high-k stacks
We calculated the optical excitation and thermal ionization energies of
oxygen vacancies in m-HfO using atomic basis sets, a non-local density
functional and periodic supercell. The thermal ionization energies of
negatively charged V and V centres are consistent with values
obtained by the electrical measurements. The results suggest that negative
oxygen vacancies are the likely candidates for intrinsic electron traps in the
hafnum-based gate stack devices.Comment: 3 pages, 2 figure
Bayes-X: a Bayesian inference tool for the analysis of X-ray observations of galaxy clusters
We present the first public release of our Bayesian inference tool, Bayes-X,
for the analysis of X-ray observations of galaxy clusters. We illustrate the
use of Bayes-X by analysing a set of four simulated clusters at z=0.2-0.9 as
they would be observed by a Chandra-like X-ray observatory. In both the
simulations and the analysis pipeline we assume that the dark matter density
follows a spherically-symmetric Navarro, Frenk and White (NFW) profile and that
the gas pressure is described by a generalised NFW (GNFW) profile. We then
perform four sets of analyses. By numerically exploring the joint probability
distribution of the cluster parameters given simulated Chandra-like data, we
show that the model and analysis technique can robustly return the simulated
cluster input quantities, constrain the cluster physical parameters and reveal
the degeneracies among the model parameters and cluster physical parameters. We
then analyse Chandra data on the nearby cluster, A262, and derive the cluster
physical profiles. To illustrate the performance of the Bayesian model
selection, we also carried out analyses assuming an Einasto profile for the
matter density and calculated the Bayes factor. The results of the model
selection analyses for the simulated data favour the NFW model as expected.
However, we find that the Einasto profile is preferred in the analysis of A262.
The Bayes-X software, which is implemented in Fortran 90, is available at
http://www.mrao.cam.ac.uk/facilities/software/bayesx/.Comment: 22 pages, 11 figure
Pattern languages in HCI: A critical review
This article presents a critical review of patterns and pattern languages in human-computer interaction (HCI). In recent years, patterns and pattern languages have received considerable attention in HCI for their potential as a means for developing and communicating information and knowledge to support good design. This review examines the background to patterns and pattern languages in HCI, and seeks to locate pattern languages in relation to other approaches to interaction design. The review explores four key issues: What is a pattern? What is a pattern language? How are patterns and pattern languages used? and How are values reflected in the pattern-based approach to design? Following on from the review, a future research agenda is proposed for patterns and pattern languages in HCI
Description and Operation of the A3 Subscale Facility
The purpose of this paper is to give an overview of the general design and operation of the A3 Subscale test facility. The goal is to provide the reader with a general understanding of what the major facility systems are, where they are located, and how they are used to meet the objectives supporting the design of the A3 altitude rocket test facility. This paper also provides the reader with the background information prior to reading the subsequent papers detailing the design and test results of the various systems described herein
When it Pays to Rush: Interpreting Morphogen Gradients Prior to Steady-State
During development, morphogen gradients precisely determine the position of
gene expression boundaries despite the inevitable presence of fluctuations.
Recent experiments suggest that some morphogen gradients may be interpreted
prior to reaching steady-state. Theoretical work has predicted that such
systems will be more robust to embryo-to-embryo fluctuations. By analysing two
experimentally motivated models of morphogen gradient formation, we investigate
the positional precision of gene expression boundaries determined by
pre-steady-state morphogen gradients in the presence of embryo-to-embryo
fluctuations, internal biochemical noise and variations in the timing of
morphogen measurement. Morphogens that are direct transcription factors are
found to be particularly sensitive to internal noise when interpreted prior to
steady-state, disadvantaging early measurement, even in the presence of large
embryo-to-embryo fluctuations. Morphogens interpreted by cell-surface receptors
can be measured prior to steady-state without significant decrease in
positional precision provided fluctuations in the timing of measurement are
small. Applying our results to experiment, we predict that Bicoid, a
transcription factor morphogen in Drosophila, is unlikely to be interpreted
prior to reaching steady-state. We also predict that Activin in Xenopus and
Nodal in zebrafish, morphogens interpreted by cell-surface receptors, can be
decoded in pre-steady-state.Comment: 18 pages, 3 figure
A Discotic Disguised as a Smectic: A Hybrid Columnar Bragg Glass
We show that discotics, lying deep in the columnar phase, can exhibit an
x-ray scattering pattern which mimics that of a somewhat unusual smectic liquid
crystal. This exotic, new glassy phase of columnar liquid crystals, which we
call a ``hybrid columnar Bragg glass'', can be achieved by confining a columnar
liquid crystal in an anisotropic random environment of e.g., strained aerogel.
Long-ranged orientational order in this phase makes {\em single domain} x-ray
scattering possible, from which a wealth of information could be extracted. We
give detailed quantitative predictions for the scattering pattern in addition
to exponents characterizing anomalous elasticity of the system.Comment: 4 RevTeX pgs, 2 eps figures. To appear in PR
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