Paolo Padovani , II Universit di Roma , Paolo Giommi , ASI, SDC and Fabrizio Fiore, ASI, SDC and Osservatorio Astronomico di Roma . Original Version: MNRAS, (1997), 284, 569 . Text copyright (c) 1997. ... We study the X-ray spectra of 114 flat-spectrum radio quasars (FSRQ) using the hardness ratios as given in the WGA catalogue of ROSAT sources. ... We find that FSRQ have a distribution of energy spectral indices ranging between 0 and 3 with a mean value alpha_x ~ 1. ... Figure 1 (13kb) . ...

... AstroCC is a coordinate conversion utility for astronomy. It accepts an object designation or the coordinates of an object and calculates coordinates in alternative systems, and at different dates, times, and locations. It also provides lunar and bright planet coordinates to aid in planning observations. ... BJD values may also be retrieved from http://astroutils.astronomy.ohio-state.edu/time/utc2bjd.html which is based on Eastman et al. ... Coordinate data are obtained from SIMBAD. ...

. ATMOSPHERIC INFLUENCE ON THE DIFFERENT RADIO-ENGINEERING . SYSTEM FUNCTIONING . The calculations of the atmospheric impact on terrestrial and satellite communication links with frequencies above 10 GHz using the ITU-R data bank. The correction of the Earth cover optical images obtained from the satellite/ . The Earth atmospheric influence on the radiowave propagation parameters in wide frequency range (from SLF to UV). Contact e-mail: . Pozhidayev Victor, Ph.D - vic@cplire.ru . © IRE RAS 1996-20 11

The silicates that produce the 10 and 18 micron features appear to be broadly similar to terrestrial minerals such as Forsterite and Enstatite. ... Where pre-solar silicate dust grains can be isolated from meteorite material, these also tend to be Mg-rich silicates rather than Fe-rich silicates. ... It has been suggested that the interstellar silicate grains have a different 10 micron feature profile than what is observed for the silicates around evolved stars. ...