7,644 research outputs found
The Virginia Sickle Cell Anemia Awareness Program: Education, Screening, and Counseling
In 1968, a program of screening for sickle trait carriers was begun as part of the work of the Hematology Division, Department of Medicine, at the Medical College of Virginia. It was felt that sickle cell anemia was more of a public health problem than was generally recognized, and in addition to instituting screening and education programs, data were collected to document the relative neglect of the problem
XMM-Newton temperature maps for five intermediate redshift clusters of galaxies
We have analyzed XMM-Newton archive data for five clusters of galaxies
(redshifts 0.223 to 0.313) covering a wide range of dynamical states, from
relaxed objects to clusters undergoing several mergers. We present here
temperature maps of the X-ray gas together with a preliminary interpretation of
the formation history of these clusters.Comment: 4 pages, 2 figs. Accepted for publication in the Proceedings of the
36th COSPAR Scientific Assembl
The merging cluster of galaxies Abell 3376: an optical view
Abell 3376 is a merging cluster of galaxies at redshift z=0.046, famous
mostly for its giant radio arcs, and shows an elongated and highly
substructured X-ray emission, but has not been analysed in detail at optical
wavelengths. We have obtained wide field images of Abell 3376 in the B band and
derive the GLF applying a statistical subtraction of the background in three
regions: a circle of 0.29 deg radius (1.5 Mpc) encompassing the whole cluster,
and two circles centered on each of the two brightest galaxies (BCG2,
northeast, coinciding with the peak of X-ray emission, and BCG1, southwest) of
radii 0.15 deg (0.775 Mpc). We also compute the GLF in the zone around BCG1,
which is covered by the WINGS survey in the B and V bands, by selecting cluster
members in the red sequence in a (B-V) versus V diagram. Finally, we discuss
the dynamical characteristics of the cluster implied by a Serna & Gerbal
analysis. The GLFs are not well fit by a single Schechter function, but
satisfactory fits are obtained by summing a Gaussian and a Schechter function.
The GLF computed by selecting galaxies in the red sequence in the region
surrounding BCG1 can also be fit by a Gaussian plus a Schechter function. An
excess of galaxies in the brightest bins is detected in the BCG1 and BCG2
regions. The dynamical analysis based on the Serna & Gerbal method shows the
existence of a main structure of 82 galaxies which can be subdivided into two
main substructures of 25 and 6 galaxies. A smaller structure of 6 galaxies is
also detected. The B band GLFs of Abell 3376 are clearly perturbed, as already
found in other merging clusters. The dynamical properties are consistent with
the existence of several substructures, in agreement with a previously
published X-ray analysis.Comment: 11 pages, 12 figures, accepted for publication in A&
The 3XMM/SDSS Stripe 82 Galaxy Cluster Survey: Cluster catalogue and discovery of two merging cluster candidates
We present a galaxy cluster survey based on XMM-Newton observations that are
located in Stripe 82 of the Sloan Digital Sky Survey (SDSS). The survey covers
an area of 11.25 deg. The X-ray cluster candidates were selected as
serendipitously extended detected sources from the third XMM-Newton
serendipitous source catalogue (3XMM-DR5). A cross-correlation of the candidate
list that comprises 94 objects with recently published X-ray and optically
selected cluster catalogues provided optical confirmations and redshift
estimates for about half of the candidate sample. We present a catalogue of
X-ray cluster candidates previously known in X-ray and/or optical bands from
the matched catalogues or NED. The catalogue consists of 54 systems with
redshift measurements in the range of 0.05-1.19 with a median of 0.36. Of
these, 45 clusters have spectroscopic confirmations as stated in the matched
catalogues. We spectroscopically confirmed another 6 clusters from the
available spectroscopic redshifts in the SDSS-DR12. The cluster catalogue
includes 17 newly X-ray discovered clusters, while the remainder were detected
in previous XMM-Newton and/or ROSAT cluster surveys. Based on the available
redshifts and fluxes given in the 3XMM-DR5 catalogue, we estimated the X-ray
luminosities and masses for the cluster sample. We also present the list of the
remaining X-ray cluster candidates (40 objects) that have no redshift
information yet in the literature. Of these candidates, 25 sources are
considered as distant cluster candidates beyond a redshift of 0.6. We also
searched for galaxy cluster mergers in our cluster sample and found two strong
candidates for newly discovered cluster mergers at redshifts of 0.11 and 0.26.
The X-ray and optical properties of these systems are presented.Comment: 17 pages, 12 figures, accepted for publication in A&A, revised
version after language editin
The Philippines: External Shocks, Adjustment Policies and Impact on Selected Development Concerns, 1973-1985
With the objective of designing and implementing more effective policies and programs in the light of external shocks, this paper assesses the impact of economic crisis and adjustment policies on basic economic and social concerns particularly on vulnerable income groups. The development path implied in this article is a strategy that is expansionary within the limits set by external finance and other policy considerations.vulnerable groups, adjustment policies
Structure determination from powder data : Mogul and CASTEP
When solving the crystal structure of complex molecules from powder data, accurately locating the global minimum can be challenging, particularly where the number of internal degrees of freedom is large. The program Mogul provides a convenient means to access typical torsion angle ranges for fragments related to the molecule of interest. The impact that the application of modal torsion angle constraints has on the structure determination process of two structure solution attempts using DASH is presented. Once solved, accurate refinement of a molecular structure against powder data can also present challenges. Geometry optimisation using density functional theory in CASTEP is shown to be an effective means to locate hydrogen atom positions reliably and return a more accurate description of molecular conformation and intermolecular interactions than global optimisation and Rietveld refinement alone
Giant Ringlike Radio Structures Around Galaxy Cluster Abell 3376
In the current paradigm of cold dark matter cosmology, large-scale structures
are assembling through hierarchical clustering of matter. In this process, an
important role is played by megaparsec (Mpc)-scale cosmic shock waves, arising
in gravity-driven supersonic flows of intergalactic matter onto dark
matter-dominated collapsing structures such as pancakes, filaments, and
clusters of galaxies. Here, we report Very Large Array telescope observations
of giant (~2 Mpc by 1.6 Mpc), ring-shaped nonthermal radio-emitting structures,
found at the outskirts of the rich cluster of galaxies Abell 3376. These
structures may trace the elusive shock waves of cosmological large-scale matter
flows, which are energetic enough to power them. These radio sources may also
be the acceleration sites where magnetic shocks are possibly boosting
cosmic-ray particles with energies of up to 10^18 to 10^19 electron volts.Comment: Published on Science, 3 November 2006. Main paper and Supporting
Online Materia
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