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Embryonic stem cell (ESC) self-renewal efficiency is determined by the level of Nanog expression. However, the mechanisms by which Nanog functions remain unclear, and in particular, direct Nanog target genes are uncharacterized. Here we investigate ESCs expressing different Nanog levels and Nanog(-/-) cells with distinct functionally inducible Nanog(More)
We present a study of the architectural requirements and scalability of the NAS Parallel Benchmarks. Through direct measurements and simulations, we identify the factors which affect the scalability of benchmark codes on two relevant and distinct platforms; a cluster of workstations and a ccNUMA SGI Origin 2000. We find that the benefit of increased global(More)
A novel gene, hetF, was identified as essential for heterocyst development in the filamentous cyanobacterium Nostoc punctiforme strain ATCC 29133. In the absence of combined nitrogen, hetF mutants were unable to differentiate heterocysts, whereas extra copies of hetF in trans induced the formation of clusters of heterocysts. Sequences hybridizing to a hetF(More)
The rostrocaudal (head-to-tail) axis is supplied by populations of progenitors at the caudal end of the embryo. Despite recent advances characterising one of these populations, the neuromesodermal progenitors, their nature and relationship to other populations remains unclear. Here we show that neuromesodermal progenitors are a single Sox2(low)T(low) entity(More)
The transcription factors Nanog and Oct4 regulate pluripotency in the pre-implantation epiblast and in derivative embryonic stem cells. During post-implantation development, the precise timing and mechanism of the loss of pluripotency is unknown. Here, we show that in the mouse, pluripotency is extinguished at the onset of somitogenesis, coincident with(More)
With the growing importance of fast system area networks in the parallel community, it is becoming common for message passing programs to run in multi-programming environments. Competing sequential and parallel jobs can distort the global coordination of communicating processes. In this paper, we describe our implementation of MPI using implicit information(More)
A viral agent was isolated from the fetal liver of an aborted equine fetus. The isolate hemagglutinated red blood cells from guinea pig, rhesus monkey and rooster. By hemagglutination inhibition tests, the isolate was shown to be antigenically distinct from parvoviruses of bovine and canine origin. Specific hemagglutination inhibiting antibody against the(More)
Isolations of rubella virus and the successful passage of this virus on grivet monkey kidney cells were reported in 1962--1963 by Parkman, Buescher, Sigurdardottir and co-workers (1, 2, 3, 4). No report of quantitative growth studies has been published to date. This report describes the results of our growth studies of rubella virus on this type of cell(More)