28 research outputs found
Distortion Isomerism of Cu(II) Chloride Adducts with Bis(2-benzimidazolyl)ethane. Synthesis, Characterization, X-ray Structures and Spectroscopy of Four Different Isomers
Metals in Catalysis, Biomimetics & Inorganic Material
Cluster Lenses
Clusters of galaxies are the most recently assembled, massive, bound
structures in the Universe. As predicted by General Relativity, given their
masses, clusters strongly deform space-time in their vicinity. Clusters act as
some of the most powerful gravitational lenses in the Universe. Light rays
traversing through clusters from distant sources are hence deflected, and the
resulting images of these distant objects therefore appear distorted and
magnified. Lensing by clusters occurs in two regimes, each with unique
observational signatures. The strong lensing regime is characterized by effects
readily seen by eye, namely, the production of giant arcs, multiple-images, and
arclets. The weak lensing regime is characterized by small deformations in the
shapes of background galaxies only detectable statistically. Cluster lenses
have been exploited successfully to address several important current questions
in cosmology: (i) the study of the lens(es) - understanding cluster mass
distributions and issues pertaining to cluster formation and evolution, as well
as constraining the nature of dark matter; (ii) the study of the lensed objects
- probing the properties of the background lensed galaxy population - which is
statistically at higher redshifts and of lower intrinsic luminosity thus
enabling the probing of galaxy formation at the earliest times right up to the
Dark Ages; and (iii) the study of the geometry of the Universe - as the
strength of lensing depends on the ratios of angular diameter distances between
the lens, source and observer, lens deflections are sensitive to the value of
cosmological parameters and offer a powerful geometric tool to probe Dark
Energy. In this review, we present the basics of cluster lensing and provide a
current status report of the field.Comment: About 120 pages - Published in Open Access at:
http://www.springerlink.com/content/j183018170485723/ . arXiv admin note:
text overlap with arXiv:astro-ph/0504478 and arXiv:1003.3674 by other author
A review of elliptical and disc galaxy structure, and modern scaling laws
A century ago, in 1911 and 1913, Plummer and then Reynolds introduced their
models to describe the radial distribution of stars in `nebulae'. This article
reviews the progress since then, providing both an historical perspective and a
contemporary review of the stellar structure of bulges, discs and elliptical
galaxies. The quantification of galaxy nuclei, such as central mass deficits
and excess nuclear light, plus the structure of dark matter halos and cD galaxy
envelopes, are discussed. Issues pertaining to spiral galaxies including dust,
bulge-to-disc ratios, bulgeless galaxies, bars and the identification of
pseudobulges are also reviewed. An array of modern scaling relations involving
sizes, luminosities, surface brightnesses and stellar concentrations are
presented, many of which are shown to be curved. These 'redshift zero'
relations not only quantify the behavior and nature of galaxies in the Universe
today, but are the modern benchmark for evolutionary studies of galaxies,
whether based on observations, N-body-simulations or semi-analytical modelling.
For example, it is shown that some of the recently discovered compact
elliptical galaxies at 1.5 < z < 2.5 may be the bulges of modern disc galaxies.Comment: Condensed version (due to Contract) of an invited review article to
appear in "Planets, Stars and Stellar
Systems"(www.springer.com/astronomy/book/978-90-481-8818-5). 500+ references
incl. many somewhat forgotten, pioneer papers. Original submission to
Springer: 07-June-201
The course of radiologic damage during the first six years of rheumatoid arthritis
Objective. To describe the radiologic course in a large cohort of patients with early rheumatoid arthritis (RA) and to analyze individual components of damage. Methods. Five hundred two patients with recent-onset RA (disease duration Results. Stable rates of progression of the SHS, erosion score, and narrowing score were found over the course of RA: the mean rates were 8.6, 5.4, and 3.2 modified Sharp units per year, respectively. The rate of progression of newly (not previously) damaged joints declined, and the rate of progression of already damaged joints (which became more damaged) increased during followup, leading to an equal contribution to progression of the SHS at 5 years. The joints of the feet, especially the fifth metatarsophalangeal joint, generally became eroded earlier and more of them became eroded compared with the joints of the hands. Conclusion. Radiologic damage progresses at a constant rate. In advanced disease, monitoring the progression of previously existing damage is as important as assessing new abnormalities in previously undamaged joints. Radiographs of the feet should be included in assessments of radiologic damage that are used in clinical intervention trials and daily practice
The course of radiologic damage during the first six years of rheumatoid arthritis
To describe the radiologic course in a large cohort of patients with early rheumatoid arthritis (RA) and to analyze individual components of damage. Five hundred two patients with recent-onset RA (disease duration <1 year) underwent annual radiologic assessment for a maximum of 6 years in this longitudinal prospective study. The study was designed to investigate the efficacy of 3 different therapeutic strategies. For the assessment of radiologic damage, radiographs of the hands and feet were scored according to the modified Sharp/van der Heijde method (SHS; range 0-448). A mean of 2.9 (range 1-7) radiographs was read per patient. Stable rates of progression of the SHS, erosion score, and narrowing score were found over the course of RA: the mean rates were 8.6, 5.4, and 3.2 modified Sharp units per year, respectively. The rate of progression of newly (not previously) damaged joints declined, and the rate of progression of already damaged joints (which became more damaged) increased during followup, leading to an equal contribution to progression of the SHS at 5 years. The joints of the feet, especially the fifth metatarsophalangeal joint, generally became eroded earlier and more of them became eroded compared with the joints of the hands. Radiologic damage progresses at a constant rate. In advanced disease, monitoring the progression of previously existing damage is as important as assessing new abnormalities in previously undamaged joints. Radiographs of the feet should be included in assessments of radiologic damage that are used in clinical intervention trials and daily practic