Analysis of total visual and CCD V-broadband observations of Comet C/1995 O1 (Hale-Bopp): 1995-2001

We developed a general method for determination of water production rates from groundbased visual observations and applied it to Comet Hale-Bopp. Our main objective is to extend the method to include total visual magnitude observations obtained with CCD detector and V filter in the analysis of total visual magnitudes. We compare the CCD V-broadband careful observations of Liller [Liller, W. Pre-perihelion CCD photometry of Comet 1995 01 (Hale-Bopp). Planet. Space Sci. 45, 1505-1513, 1997; Liller, W. CCD photometry of Comet C/1995 O1 (Hale-Bopp): 1995-2000. Int. Comet Quart. 23(3), 93-97, 2001] with the total visual magnitude observations from experienced international observers found in the International Comet Quarterly (ICQ) archive. A data set of similar to 400 CCD observations covering about the same 6 years time span of the similar to 12,000 ICQ selected total visual magnitude observations were used in the analysis. A least-square method applied to the water production rates, yields power laws as a function of the heliocentric distances for the pre- and post-perihelion phases. The average dimension of the nucleus as well as its effective active area is determined and compared with values published in the literature. (C) 2009 COSPAR. Published by Elsevier Ltd. All rights reserved.

Genetic typing of Trypanosoma cruzi isolates from different hosts and geographical areas of western Venezuela

A total of 72 Trypanosoma cruzi isolates from different hosts and geographical regions of western Venezuela, where Chagas disease is endemic, were typed using ribosomal and mini-exon gene markers. The isolates were obtained from wild, peridomestic and domestic sources including triatomine-bugs, human acute chagasic patients and other mammals. Results showed that T. cruzi two major phylogenetic lineages, T. cruzi I and T. cruzi II were present. However, a remarkable predominance of T. cruzi I (96%) over T. cruzi II (4%) was observed. The present results suggest that in western Venezuela circulation of both T. cruzi I and T. cruzi II isolates is independent from the source of isolation and the geographical area where they occur, with predominance of T. cruzi I. The epidemiological significance of the present results is discussed.