231 research outputs found
Schedule Analysis of Concurrent Logic Programs
A compilation technique is proposed for concurrent logic programs called schedule analysis. Schedule analysis deduces at compile-time a partial schedule for the processes of a program by partitioning the atoms of each clause into threads. Threads are totally ordered sets of atoms whose relative ordering is determined by a scheduler. Threads reduce scheduler activity and permit a wealth of traditional Prolog optimisations to be applied to the program. A framework for schedule analysis is proposed and this defines a procedure for creating threads. A safety result is presented stating the conditions under which the work of the scheduler can be reduced from ordering processes to ordering threads. Schedule analysis has been integrated into a compiler and implementation has suggested that it can play a central role in compilation. Optimisations which follow from schedule analysis include a reduction in scheduling, the removal of synchronisation checks, the simplification of unification, decreased garbage collection and a reduction in argument copying
The Neoproterozoic Rivieradal Group of Kronprins Christian Land, eastern North Greenland
The Rivieradal Group, formally defined here, is confined to the Vandredalen thrust sheet of the Caledonian orogen in Kronprins Christian Land, eastern North Greenland. It comprises a succession of Neoproterozoic siliciclastic sediments that represent the fill of a half-graben basin. The syn-rift Rivieradal Group is overlain by post-rift sediments of the Hagen Fjord Group. The latter succession is present in both the thrust sheet and the Caledonian foreland to the west. In the foreland, where the Rivieradal Group is not represented, the Hagen Fjord Group disconformably overlies Palaeoproterozoic–Mesoproterozoic sandstones of the Independence Fjord Group
Vaginal Flora in Postmenopausal Women: The Effect of Estrogen Replacement
Objective:To determine the effect of estrogen replacement therapy (ERT)
on the vaginal flora of postmenopausal women
Solid-phase extraction and purification of membrane proteins using a UV-modified PMMA microfluidic bioaffinity mu SPE device
We present a novel microfluidic solid-phase extraction (??SPE) device for the affinity enrichment of biotinylated membrane proteins from whole cell lysates. The device offers features that address challenges currently associated with the extraction and purification of membrane proteins from whole cell lysates, including the ability to release the enriched membrane protein fraction from the extraction surface so that they are available for downstream processing. The extraction bed was fabricated in PMMA using hot embossing and was comprised of 3600 micropillars. Activation of the PMMA micropillars by UV/O3 treatment permitted generation of surface-confined carboxylic acid groups and the covalent attachment of NeutrAvidin onto the ??SPE device surfaces, which was used to affinity select biotinylated MCF-7 membrane proteins directly from whole cell lysates. The inclusion of a disulfide linker within the biotin moiety permitted release of the isolated membrane proteins via DTT incubation. Very low levels (???20 fmol) of membrane proteins could be isolated and recovered with ???89% efficiency with a bed capacity of 1.7 pmol. Western blotting indicated no traces of cytosolic proteins in the membrane protein fraction as compared to significant contamination using a commercial detergent-based method. We highlight future avenues for enhanced extraction efficiency and increased dynamic range of the ??SPE device using computational simulations of different micropillar geometries to guide future device designs.close2
Influence of a knot on the strength of a polymer strand
Many experiments have been done to determine the relative strength of
different knots, and these show that the break in a knotted rope almost
invariably occurs at a point just outside the `entrance' to the knot. The
influence of knots on the properties of polymers has become of great interest,
in part because of their effect on mechanical properties. Knot theory applied
to the topology of macromolecules indicates that the simple trefoil or
`overhand' knot is likely to be present with high probability in any long
polymer strand. Fragments of DNA have been observed to contain such knots in
experiments and computer simulations. Here we use {\it ab initio} computational
methods to investigate the effect of a trefoil knot on the breaking strength of
a polymer strand. We find that the knot weakens the strand significantly, and
that, like a knotted rope, it breaks under tension at the entrance to the knot.Comment: 3 pages, 4 figure
Microfluidics for the detection of minimal residual disease in acute myeloid leukemia patients using circulating leukemic cells selected from blood
Microfluidic assay for the selection of circulating leukemic cells from peripheral blood for the early detection of minimal residual disease in acute myeloid leukemia patients
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