Late Pleistocene horse and camel hunting at the southern margin of the ice-free corridor: Reassessing the age of Wally’s Beach, Canada

The only certain evidence for prehistoric human hunting of horse and camel in North America occurs at the Wally’s Beach site, Canada. Here, the butchered remains of seven horses and one camel are associated with 29 nondiagnostic lithic artifacts. Twenty-seven new radiocarbon ages on the bones of these animals revise the age of these kill and butchering localities to 13,300 calibrated y B.P. The tight chronological clustering of the eight kill localities at Wally’s Beach indicates these animals were killed over a short period. Human hunting of horse and camel in Canada, coupled with mammoth, mastodon, sloth, and gomphothere hunting documented at other sites from 14,800–12,700 calibrated y B.P., show that 6 of the 36 genera of megafauna that went extinct by approximately 12,700 calibrated y B.P. were hunted by humans. This study shows the importance of accurate geochronology, without which significant discoveries will go unrecognized and the empirical data used to build models explaining the peopling of the Americas and Pleistocene extinctions will be in error.

Capitolia

Capitolia, temples to the triad of divinities Iuppiter Optimus Maximus, Iuno Regina and Minerva Augusta, are often considered part of the standard urban ‘kit’ of Roman colonies. Their placement at one end of the forum is sometimes seen as schematizing and replicating in miniature the relationship between the Capitolium at Rome and the Forum Romanum below it. Reliably attested Capitolia are, however, rarer in the provinces than this widespread view assumes and there seems to be no relationship between civic status and the erection of a Capitolium. Indeed, outside Italy there are very few Capitolia other than in the African provinces, where nearly all known examples belong to the second or early third century a.d., mostly in the Antonine period. This regional and chronological clustering demands explanation, and since it comes too late to be associated with the foundation of colonies, and there is no pattern of correlation with upgrades in civic status, we propose that the explanation has to do with the growing power and influence of North African élites, who introduced the phenomenon from Rome. Rather than being a form of temple imposed from the centre on the provinces, Capitolia were adopted by provincial élites on the basis of their relationship with Rome.

Variation in Salmonella enterica Serovar Typhi IncHI1 Plasmids during the Global Spread of Resistant Typhoid Fever

ABSTRACT A global collection of plasmids of the IncHI1 incompatibility group from Salmonella enterica serovar Typhi were analyzed by using a combination of DNA sequencing, DNA sequence analysis, PCR, and microarrays. The IncHI1 resistance plasmids of serovar Typhi display a backbone of conserved gene content and arrangement, within which are embedded preferred acquisition sites for horizontal DNA transfer events. The variable regions appear to be preferred acquisition sites for DNA, most likely through composite transposition, which is presumably driven by the acquisition of resistance genes. Plasmid multilocus sequence typing, a molecular typing method for IncHI1 plasmids, was developed using variation in six conserved loci to trace the spread of these plasmids and to elucidate their evolutionary relationships. The application of this method to a collection of 36 IncHI1 plasmids revealed a chronological clustering of plasmids despite their difference in geographical origins. Our findings suggest that the predominant plasmid types present after 1993 have not evolved directly from the earlier predominant plasmid type but have displaced them. We propose that antibiotic selection acts to maintain resistance genes on the plasmid, but there is also competition between plasmids encoding the same resistance phenotype.

Structure en taille des crustacés planctoniques d'un lac dimictique du Bouclier canadien

From May 1981 to July 1982, 28 zooplankton samples were taken from the pelagic zone of Lake Cromwell, Quebec. Seasonal variation in the size structure of the planktonic crustacean community was studied using three different multidimensional analyses: intermediate linkage clustering, principal coordinate analysis, and chronological clustering. The results of these analyses showed the existence of distinct patterns in the size distribution of planktonic crustaceans during the annual cycle. During winter, the community was dominated by intermediate-sized organisms (0.51–0.60 mm), and by a few of larger size (0.96 mm). In springtime, nauplii appeared, and the larger size classes were reduced, giving the size spectra a characteristic shape. Small organisms (0.06–0.22 mm) dominated the population throughout the summer. The fall season was characterized by the opposite observation: small organisms slowly decreased in number while the intermediate classes (0.51–0.60 mm) increased in number to reach their peak in winter. These size–frequency patterns may be related to varying food levels and composition throughout the year.