Daniel S. Hudson

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PURPOSE OF STUDY Burns are one of the leading causes of injury-related deaths in Iran. We conducted a study to investigate features of burns in rural areas of Ardabil Province from October 2004 through March 2005, with an aim to providing content for effective prevention programs. BASIC PROCEDURES This study employed longitudinal prospective methodology.(More)
Active galactic nuclei (AGN) at the center of galaxy clusters with gas cooling times that are much shorter than the Hubble time have emerged as heating agents powerful enough to prevent further cooling of the intracluster medium (ICM). We carried out an intensive study of the AGN heating−ICM cooling network by comparing various cluster parameters to the(More)
Context. Cosmological structure formation offers insights on all of the universe’s components: baryonic matter, dark matter, and, notably, dark energy. The mass function of galaxy clusters at high redshifts is a particularly useful probe to learn about the history of structure formation and constrain cosmological parameters. Aims. We aim at deriving(More)
Context. We report the first X-ray detection of a proto-supermassive binary black hole at the centre of Abell 400. Using the Chandra Advanced CCD Imaging Spectrometer, we are able to clearly resolve the two active galactic nuclei in 3C 75, the well known double radio source at the centre of Abell 400. Aims. Through analysis of the new Chandra observation of(More)
We have analyzed the Chandra, BeppoSax, and ROSAT PSPC observations of Abell 754 and report evidence of a soft, diffuse X-ray component. The emission is peaked in the cluster center and is detected out to 8 arcmin from the X-ray center. Fitting a thermal model to the combined BeppoSax and PSPC spectra show excess emission below 1 keV in the PSPC and above(More)
We report the first localization of diffuse, non-thermal, X-ray emission from a nearby galaxy cluster. Using Chandra data, we have isolated a diffuse non-thermal X-ray component with a photon index, ΓX = 2.21 +0.14 −0.15 and a flux of 9.5 +1.1 −2.5 × 10 −5 photons cm s keV at 1 keV, that extends from ∼1.5 to ∼2.5 to the south of the X-ray flux peak.(More)
Fifty-eight white-necked ravens (Corvus cryptoleucus) were examined for ectoparasites. Brueelia afzali and Philopterus ocellatus osborni were the most abundant mallophagans while Colpocephalum fregili and Myrsidea interruptus were the least common. The white-necked raven is listed as a new host for P. ocellatus osborni. Host sexual selection is indicated by(More)
Evolution in the mass function of galaxy clusters sensitively traces cosmological structure formation. The number density of massive clusters as a function of redshift can be used to constrain cosmological parameters. We aim at deriving a robust mass function by a detailed comparison of cluster masses deduced from observations of their X-ray and weak(More)