Radio pulses from air showers at Mt. Chacaltaya

Abstract

Pulses from a helical antenna and from a broad-band log-periodic TV antenna were photographed when any of various trigger requirements were met. In order to use arrival directions to correlate radio pulses with air showers, the antennas were pointed away from the zenith. Results for arrival direction correlation are presented. Preliminary evidence that the radio pulse energy increases with decreasing frequency in the region 40-60 MHz is presented. In addition to triggering on air shower particles alone, we also successfully used a coincidence of radio pulses and shower particles as a trigger. Latest preliminary results obtained with the TV antenna indicate that radio pulses may not be polarized perpendicular to the earth's magnetic field.

Sequence variability in avocado sunblotch viroid (ASBV)

“…From a structural point of view it has a limited sequence homology with other members of this group (1), and functionally, ASBV is the only viroid for which it has been demostrated that RNA transcripts generated in vitro from cDNA clones are able to be processed at specific sites in the isence of enzymes (2). Although sequence heterogeneity among different isolates of ASBV has been suggested (3,4), only the sequence of an Australian isolate of this viroid has been published so far (1). Using two different experimental approaches, we have determined the complete nucleotide sequence of a Spanish isolate of ASBV obtained from an avocado tree cv.…”