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Advanced optical imaging methods for investigating manuscripts
This paper gives an overview of advanced optical imaging methods relevant to the study of manuscripts. While some of the methods covered are well established, others are very much in active development. âOpticalâ in this context is loosely defined to cover the near ultraviolet, visible and the near infrared part of the electromagnetic spectrum. Optical imaging methods are in general non-destructive and can be applied in situ. They are non-invasive if care is taken to ensure a safe dosage of illumination during the imaging process. The examples given in this paper are biased towards work that the author has been involved in. This is by no means a comprehensive review. The aim of the paper is to illustrate how advanced optical imaging techniques can assist in the investigation of manuscripts
A Radio Halo Found in the Hottest Known Cluster of Galaxies 1E0658-56
We report the detection of a diffuse radio halo source in the hottest known
cluster of galaxies 1E0658-56 (RXJ0658-5557). The radio halo has a morphology
similar to the X-ray emission from the hot intracluster medium. The detection
of such a strong radio halo in such a hot cluster is further evidence to the
link between X-ray temperature and cluster-wide radio halos. We describe a new
model for the origin of cluster-wide radio halo sources involving a direct
connection between the X-ray emitting thermal particles and the radio emitting
relativistic particles.Comment: 6 pages, 5 postscript figues, Latex, to appear in proceedings of the
Ringberg workshop on "Diffuse Thermal and Relativistic Plasma in Galaxy
Clusters", April 1999, H. Boehringer, L. Feretti, P. Schuecker (eds.
Ultra-high resolution Fourier domain optical coherence tomography for resolving thin layers in painted works of art
While OCT has been applied to the non-invasive examination of the stratigraphy of paint layers in recent years, it has been recognized that the resolutions of commercially available OCT cannot compete in depth resolution with conventional microscopic examination of cross-sections of paint samples. It is necessary to achieve resolutions better than 3 microns to resolve the thinnest layers of paint and varnish. In this paper, we demonstrate a Fourier domain ultrahigh resolution OCT at 810nm with depth resolution of 1.8ÎŒm in air (or 1.2ÎŒm in varnish or paint)
Vacua and Exact Solutions in Lower- Limits of EGB
We consider the action principles that are the lower dimensional limits of
the Einstein-Gauss-Bonnet gravity {\it via} the Kaluza-Klein route. We study
the vacua and obtain some exact solutions. We find that the reality condition
of the theories may select one vacuum over the other from the two vacua that
typically arise in Einstein-Gauss-Bonnet gravity. We obtain exact black hole
and cosmological solutions carrying scalar hair, including scalar hairy BTZ
black holes with both mass and angular momentum turned on. We also discuss the
holographic central charges in the asymptotic AdS backgrounds.Comment: Latex, 19 page
Bulk Entanglement Spectrum Reveals Quantum Criticality within a Topological State
A quantum phase transition is usually achieved by tuning physical parameters
in a Hamiltonian at zero temperature. Here, we demonstrate that the ground
state of a topological phase itself encodes critical properties of its
transition to a trivial phase. To extract this information, we introduce a
partition of the system into two subsystems both of which extend throughout the
bulk in all directions. The resulting bulk entanglement spectrum has a
low-lying part that resembles the excitation spectrum of a bulk Hamiltonian,
which allows us to probe a topological phase transition from a single
wavefunction by tuning either the geometry of the partition or the entanglement
temperature. As an example, this remarkable correspondence between topological
phase transition and entanglement criticality is rigorously established for
integer quantum Hall states.Comment: 5 pages, 2 figures, 3 pages of Supplementary Materia
Efficacy of rehabilitation interventions in rheumatic conditions
All industrialized nations are facing a crisis in health care financing. Rising expectations coupled with increasing specialization and technologic capacities have forced health care payers to examine their assumptions and to seek data on the outcomes of medical interventions. Clinical investigators who have been taught to use randomized controlled trials that evaluate efficacy under experimental conditions have been redirected toward studies that can help answer health policy questions. Such studies examine the effectiveness of interventions in more realistic settings on a richer array of patient-centered outcomes such as function and consider cost effectiveness and relative cost effectiveness. Rehabilitation interventions, which are by and large pragmatic, have never had a strong scientific basis grounded in controlled trials, and this lack of evidence has put tremendous pressure on clinicians to justify their practices. In this article, we review the recent literature on effectiveness of rehabilitation interventions in rheumatic disorders
Non-invasive investigations of a wall painting using optical coherence tomography and hyperspectral imaging
Multispectral and hyperspectral imaging are efficient methods of measuring spectral reflectance at high spatial resolution. This non-invasive technique has been applied to the imaging of paintings over the last 20 years. PRISMS (Portable Remote Imaging System for Multispectral Scanning) was designed specifically for imaging wall paintings. Optical Coherence Tomography (OCT) is a low coherence interferometric technique capable of fast non-invasive imaging of subsurface microstructure. This paper shows the first application of in situ OCT imaging of a wall painting. The combination of PRISMS and OCT gives information on the varnish and paint layer structure, pigment identification, the state of degradation of the paint and varnish layers and informing curators on the painting schemes and techniques
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