A checklist of chromosome numbers and karyotypes of Amazonian freshwater fishes

Une liste des nombres de chromosomes de 211 espèces de poisson du bassin amazonien est présentée. Ces espèces, appartenant à 5 ordres, sont caractérisées par une grande variabilité du nombre de chromosomes (2n = 22 à 2n = 134), par la présence de chromosomes sexuels et de polymorphisme chromosomique chez certaines espèces, et enfin par une grande spécificité des bandes C et des sites des régions de l'organisateur du nucléole. (Résumé d'auteur

Karyological analysis of Proechimys cuvieri and Proechimys guyannensis (Rodentia, Echimyidae) from central Amazon

The aim was to characterize the karyotype of rodents of the genus Proechimys from three localities in the central Brazilian Amazon, in the search for new markers that might shed light on our understanding of the taxonomy and evolutionary history of this taxon. Two karyotypes were found, viz., 2n = 28, FN = 46 in individuals from the NRSP (Cuieiras River) and REMAN (Manaus), and 2n = 46, FN = 50 in individuals from the Balbina Hydroelectric Plant. While individuals with the karyotype with 2n = 28 chromosomes were morphologically associated with Proechimys cuvieri, their karyotype shared similarities with those of the same diploid number in two other regions. Although three karyotypes are described for Proechimys cuvieri, no geographic distribution pattern that defined a cline could be identified. Based on the morphological examination of voucher specimens and additional results from molecular analysis, the karyotype with 2n = 46 and FN = 50 could be associated with P. guyannensis

BRS Cainguá, a blackberry fresh-market cultivar.

Uma das razões para a baixa demanda de amoras do mercado no Brasil é o sabor ácido da fruta fresca. Os frutos da cultivar BRS Cainguá, recém-lançada, têm um sabor melhor e uma forma muito atraente

Instability and `Sausage-String' Appearance in Blood Vessels during High Blood Pressure

A new Rayleigh-type instability is proposed to explain the `sausage-string' pattern of alternating constrictions and dilatations formed in blood vessels under influence of a vasoconstricting agent. Our theory involves the nonlinear elasticity characteristics of the vessel wall, and provides predictions for the conditions under which the cylindrical form of a blood vessel becomes unstable.Comment: 4 pages, 4 figures submitted to Physical Review Letter

A COMPARISON OF CHOLINESTERASE DISTRIBUTION IN THE CEREBELLUM OF SEVERAL SPECIES *

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65142/1/j.1471-4159.1964.tb06717.x.pd