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The Vietnam Era Twin Registry consists of 4,774 male-male twin pairs born between 1939 and 1957 with both brothers having served in the United States military during the Vietnam War. The registry was originally developed to provide the best control group for Vietnam-exposed servicemen to study the long-term health consequences of service in Vietnam.(More)
Xenon computerized tomography (Xe CT) blood flow studies were conducted in 25 patients referred for a possible extracranial-intracranial bypass procedure for occlusive vascular disease in one or more extra- or intracranial vessels. These studies were helpful in selecting eight candidates for surgery. The Xe CT studies were performed at one or two brain(More)
Computed tomography (CT) using metrizamide is a valuable tool in the neuroradiologic evaluation of the spinal cord, but CT must be used with care when measuring object size because size may vary with different window center (level) settings. A simple method to determine appropriate window center (level) settings during CT object measurement is described. A(More)
  • J E Barnes
  • 1992
Understanding how contrast is produced and controlled in computed tomography (CT) is essential to proper application of this modality. In the typical CT scanner, a narrow x-ray beam in the section thickness direction and an air gap in the section plane are used to reduce scatter and improve contrast. High- and low-contrast detectability of a CT scanner are(More)
We present new VLA C ] D array H I observations and optical and near-infrared imaging of the well-known interacting system NGC 4038/39, " " The Antennae.ÏÏ At low spatial resolution (D40A), the radio data reach a limiting column density of D1019 cm~2 (2.5 p), providing signiÐcantly deeper mapping of the tidal features than a †orded by earlier H I maps. At(More)
The distribution of black hole (BH) masses M • in galaxies is constrained by photometric and kinematic studies of individual galaxies, and by the properties of the quasar population. I review our understanding of these topics, present new results of adiabatic BH growth models for HST photometry of elliptical galaxies with brightness profiles of the 'core'(More)