Radio Observations of 4079 Quasars

Using the NVSS radio catalog, we have searched for radio emission from 4079 quasars taken from the 1996 version of the Veron-Cetty and Veron (1996) quasar catalog. The comparison resulted in the positive detection of radio emission from 799 quasars. Of these, 168 are new radio detections. Examination of the radio luminosities shows a dramatic increase in the fraction of radio-loud quasars from the current epoch to z=0.5 and a gradual decline beyond z=1.0. Inspection of the radio-loud fraction as a function of M_B shows little dependence fainter than M_B=-29.5.Comment: 25 pages, including 9 figures and 1 tabl

Far infrared observations of crab-like supernova remnants

Using the Infrared Astronomy Satellite (IRAS) data, an investigation was begun of the far infrared properties of Crab-like supernova remnants and other synchrotron nebulae. Both the co-added scanning data and, where available, pointed observations were examined. To date infrared emission was found from two Crab-like remnants: G24.7+0.6 in which the infrared source near the center of the object was shown to be a compact HII region with EM greater than or approximately 10 to the 7th pc/cm(6); and G0.9+0.1 where a marginal detection of a 25 micron source coincident with the remnant core was used to set limits on the energetics of this synchrotron nebula. Further work, in progress under a second year of this program, should yield additional information concerning the distribution of initial pulsar spin periods and the evolution of synchrotron nebulae

A Suboptimal Receiver with Turbo Block Coding for Ultra-Wideband Communications

In this paper, the performance of adaptive equalization and turbo product coding is investigated for pulse-based UWB communications in short-range indoor environments. The sensitivity of adaptive LMS linear and nonlinear (decision-feedback) equalizers with respect to the number of training symbols and number of taps is considered. To reduce the error performance variation with respect to changing channel conditions, a turbo product code (TPC) with two component (31,26,3) Hamming codes is proposed. We report simulation results showing that channel coding not only improves error performance, but also reduces significantly the sensitivity of UWB systems in short-range indoor wireless communications

Radio AGN in 13,240 galaxy clusters from the Sloan Digital Sky Survey

We correlate the positions of 13,240 Brightest Cluster Galaxies (BCGs) with 0.1 <= z <= 0.3 from the maxBCG catalog with radio sources from the FIRST survey to study the sizes and distributions of radio AGN in galaxy clusters. We find that 19.7% of our BCGs are associated with FIRST sources, and this fraction depends on the stellar mass of the BCG, and to a lesser extent on the richness of the parent cluster (in the sense of increasing radio loudness with increasing mass). The intrinsic size of the radio emission associated with the BCGs peaks at 55 kpc, with a tail extending to 200 kpc. The radio power of the extended sources places them on the divide between FR I and FR II type sources, while sources compact in the radio tend to be somewhat less radio-luminous. We also detect an excess of radio sources associated with the cluster, instead of with the BCG itself, extending out to ~1.4 Mpc.Comment: 14 pages, 6 figures, accepted for publication in ApJ

The Condensation of the Aminophenols with Maleic Anhydride

In the classification of organic reactions, condensation is used in two different ways. In a very narrow sense, condensation means any reaction in which a carbon to carbon linkage is formed. In a broad sense, it refers to an organic double decomposition reaction in which the reactants are both large in molecules, and one of the products is a small molecule such as water, ammonia, or hydrogen chloride. An example of a condensation, as defined in the narrow sense, would be the reaction of acetaldehyde to form aldol. However, if the aldol is converted to crotonaldehyde with the elimination of water, then it can be classified as a condensation in the broad sense as well. Theoretically, a condensation reaction can be considered as a reaction which involves preliminary addition followed by an elimination reaction. Many condensation reactions proceed rapidly when the reactants are mixed together at a suitable temperature, but others require condensing agents such as acids, bases, phosphorus pentoxide or zinc chloride. Sometimes these condensing agents act as true catalysts, but in other cases they are used to aid in the elimination of water. Today many condensation reactions are known and much could be said about them. In this research project, the primary interest is focused on the condensation of a phenolic compound and maleic anhydride to produce an acid-base indicator