8 research outputs found
Overview of Saturn lightning observations
The lightning activity in Saturn's atmosphere has been monitored by Cassini
for more than six years. The continuous observations of the radio signatures
called SEDs (Saturn Electrostatic Discharges) combine favorably with imaging
observations of related cloud features as well as direct observations of
flash-illuminated cloud tops. The Cassini RPWS (Radio and Plasma Wave Science)
instrument and ISS (Imaging Science Subsystem) in orbit around Saturn also
received ground-based support: The intense SED radio waves were also detected
by the giant UTR-2 radio telescope, and committed amateurs observed SED-related
white spots with their backyard optical telescopes. Furthermore, the Cassini
VIMS (Visual and Infrared Mapping Spectrometer) and CIRS (Composite Infrared
Spectrometer) instruments have provided some information on chemical
constituents possibly created by the lightning discharges and transported
upward to Saturn's upper atmosphere by vertical convection. In this paper we
summarize the main results on Saturn lightning provided by this
multi-instrumental approach and compare Saturn lightning to lightning on
Jupiter and Earth.Comment: 10 pages, 6 figures, 2 tables; Proc. PRE VII conference Graz Sept.
201
Positive selection on panpulmonate mitogenomes provide new clues on adaptations to terrestrial life
Overview of Saturn Lightning Observations. Planetary Radio Emissions| PLANETARY RADIO EMISSIONS VII 7|
The lightning activity in Saturn’s atmosphere has been monitored by Cassini for more than six years. The continuous observations of the radio signatures called SEDs (Saturn Electrostatic Discharges) combine favorably with imaging observations of related cloud features as well as direct observations of flash–illuminated cloud tops. The Cassini RPWS (Radio and Plasma Wave Science) instrument and ISS (Imaging Science Subsystem) in orbit around Saturn also received ground–based support: The intense SED radio waves were also detected by the giant UTR–2 radio telescope, and committed amateurs observed SED–related white spots with their backyard optical telescopes. Furthermore, the Cassini VIMS (Visual and Infrared Mapping Spectrometer) and CIRS (Composite Infrared Spectrometer) instruments have provided some information on chemical constituents possibly created by the lightning discharges and transported upward to Saturn’s upper atmosphere by vertical convection. In this paper we summarize the main results on Saturn lightning provided by this multi–instrumental approach and compare Saturn lightning to lightning on Jupiter and Earth
Immunolocalization of alpha-keratins and associated beta-proteins in lizard epidermis shows that acidic keratins mix with basic keratin-associated beta-proteins
Promiscuous Dimerization Between the Caenorhabditis elegans IF Proteins and a Hypothesis to Explain How Multiple IFs Persist Over Evolutionary Time
Dynamic evolution of the alpha (a) and beta (ß) keratins has accompanied integument diversification and the adaptation of birds into novel lifestyles
Background: Vertebrate skin appendages are constructed of keratins produced by multigene families. Alpha (a) keratins are found in all vertebrates, while beta (ß) keratins are found exclusively in reptiles and birds. We have studied the molecular evolution of these gene families in the genomes of 48 phylogenetically diverse birds and their expression in the scales and feathers of the chicken.Results: We found that the total number of a-keratins is lower in birds than mammals and non-avian reptiles, yet two a-keratin genes (KRT42 and KRT75) have expanded in birds. The ß-keratins, however, demonstrate a dynamic evolution associated with avian lifestyle. The avian specific feather ß-keratins comprise a large majority of the total number of ß-keratins, but independently derived lineages of aquatic and predatory birds have smaller proportions of feather ß-keratin genes and larger proportions of keratinocyte ß-keratin genes. Additionally, birds of prey have a larger proportion of claw ß-keratins. Analysis of a- and ß-keratin expression during development of chicken scales and feathers demonstrates that while a-keratins are expressed in these tissues, the number and magnitude of expressed ß-keratin genes far exceeds that of a-keratins.Conclusions: These results support the view that the number of a- and ß-keratin genes expressed, the proportion of the ß-keratin subfamily genes expressed and the diversification of the ß-keratin genes have been important for the evolution of the feather and the adaptation of birds into multiple ecological niches