ABSTRACT
An amendment to this paper has been published and can be accessed via a link at the top of the paper.
ABSTRACT
Guinea pigs (Cavia spp.) have a long association with humans. From as early as 10,000 years ago they were a wild food source. Later, domesticated Cavia porcellus were dispersed well beyond their native range through pre-Columbian exchange networks and, more recently, widely across the globe. Here we present 46 complete mitogenomes of archaeological guinea pigs from sites in Peru, Bolivia, Colombia, the Caribbean, Belgium and the United States to elucidate their evolutionary history, origins and paths of dispersal. Our results indicate an independent centre of domestication of Cavia in the eastern Colombian Highlands. We identify a Peruvian origin for the initial introduction of domesticated guinea pigs (Cavia porcellus) beyond South America into the Caribbean. We also demonstrate that Peru was the probable source of the earliest known guinea pigs transported, as part of the exotic pet trade, to both Europe and the southeastern United States. Finally, we identify a modern reintroduction of guinea pigs to Puerto Rico, where local inhabitants use them for food. This research demonstrates that the natural and cultural history of guinea pigs is more complex than previously known and has implications for other studies regarding regional to global-scale studies of mammal domestication, translocation, and distribution.
Subject(s)
DNA, Ancient/analysis , DNA, Mitochondrial/analysis , Guinea Pigs/classification , Mitochondria/genetics , Sequence Analysis, DNA/veterinary , Animals , Belgium , Bolivia , Colombia , Domestication , Evolution, Molecular , Guinea Pigs/genetics , Peru , Phylogeny , Phylogeography , Population Dynamics , Puerto Rico , United StatesABSTRACT
A new interferometer has been developed which combines aspects of a Michelson interferometer with the storage capabilities of holography. The instrument makes it possible to compare interferometrically beams that are not coherent with one another. The instrument was used to measure fidelity of phase conjugation by common mode rejection of aberrators.
ABSTRACT
We have investigated experimentally the parameters which govern the effective interaction length at threshold for phase conjugation due to stimulated Brillouin scattering. We found the length to be the shorter of the following parameters: the cell length, 3 times the coherence length or 5 times the Rayleigh range of the input laser radiation. We have also found that the fidelity of the return depends strongly on the coherence length when this parameter is much shorter than the cell length. Results are also presented on fluctuations in fidelity at high power and long pulse lengths.
