4,917 research outputs found

    Caraid nan Gaidheal and 'Friend of Emigration': Gaelic emigration literature of the 1840s

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    This study focuses on Gaelic emigration literature which was published in the aftermath of the Highland potato famine of 1836-37 and before that of 1846-50. The end of the eighteenth century had witnessed a steady flow of emigrants out of the Highlands in response to a complex mix of factors, including landlord pressure, population growth and the prospect of a more prosperous future elsewhere

    Fine Details of the Nodal Electronic Excitations in Bi2_2Sr2_2CaCu2_2O8+δ_{8+\delta}

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    Very high energy resolution photoemission experiments on high quality samples of optimally doped Bi2_2Sr2_2CaCu2_2O8+δ_{8+\delta} show new features in the low-energy electronic excitations. A marked change in the binding energy and temperature dependence of the near-nodal scattering rates is observed near the superconducting transition temperature, TCT_C. The temperature slope of the scattering rate measured at low energy shows a discontinuity at ~TCT_C. In the superconducting state, coherent excitations are found with the scattering rates showing a cubic dependence on frequency and temperature. The superconducting gap has a d-wave magnitude with negligible contribution from higher harmonics. Further, the bi-layer splitting has been found to be finite at the nodal point.Comment: 5 pages, 4 figure

    THE ANTICOAGULANT AND ANTILYMPHOMA PROPERTIES OF ARSENIC AZOPROTEINS : I. ANTICOAGULANT EFFECTS OF ARSENIC AZOPROTEINS IN VIVO AND IN VITRO: COMPARISON OF ARSENICALS AS ANTICOAGULANTS AND AS ANTILYMPHOMA AGENTS: MOLECULAR STRUCTURE IN RELATION TO ANTICOAGULANT AND ANTILYMPHOMA PROPERTIES

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    Experiments given in this paper have shown that 4-arsonophenylazoproteins possess marked anticoagulant activity both in vivo and in vitro. Mice and rabbits given moderate amounts of the arsenic azoprotein, for example, often bled to death from injuries that proved trivial in control animals, and their blood remained liquid during many hours' postmortem even when left in contact with transected tissues, fibrinolysis having no part in the outcome. So, too, the addition of minute amounts of 4-arsonophenylazoprotein to plasma procured from citrated rabbit or human blood greatly prolonged the time required for clotting after recalcification. Other arsenic-containing compounds,—for example, those in which arsenic See PDF for Structure was joined to amino acids or peptides through the azo linkage, or to proteins through couplings other than the azo linkage,—were largely devoid of anticoagulant and antilymphoma effects. The findings as a whole show clearly that the structural requirements for anticoagulant and antilymphoma effects are: (a) possession of negatively charged arsonic or arsinoso groups, (b) large molecular size (protein), and (c) linkage of arsenic-containing groups to protein through the azo bond. Two acidic azoproteins that were devoid of arsenic,—namely 4-carboxyphenylazoprotein and 4-sulfonophenylazoprotein,—were also found to have marked anticoagulant effects in vitro, but they had no inhibitory action against cells of Lymphoma 6C3HED in vivo, even when they were given to mice in maximum tolerated amounts. The essential part played by arsenic in the antilymphoma activity of arsenic azoproteins was further emphasized by the action of dimercaprol (BAL) in preventing the antilymphoma effects of 4-arsonophenylazoprotein on Lymphoma 6C3HED cells in vivo. In an associated paper the anticoagulant and antilymphoma effects of 4-arsonophenylazoproteins are studied further, and consideration is given to the ways in which these effects may be brought about

    On the Reconstructed Fermi Surface in the Underdoped Cuprates

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    The Fermi surface topologies of underdoped samples the high-Tc superconductor Bi2212 have been measured with angle resolved photoemission. By examining thermally excited states above the Fermi level, we show that the Fermi surfaces in the pseudogap phase of underdoped samples are actually composed of fully enclosed hole pockets. The spectral weight of these pockets is vanishingly small at the anti-ferromagnetic zone boundary, which creates the illusion of Fermi "arcs" in standard photoemission measurements. The area of the pockets as measured in this study is consistent with the doping level, and hence carrier density, of the samples measured. Furthermore, the shape and area of the pockets is well reproduced by a phenomenological model of the pseudogap phase as a spin liquid.Comment: 4 pages, 4 figures. Submitted to Physics Review Letter

    Comparison of three commercial sparse-matrix crystallization screens

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    Sparse-matrix sampling using commercially available crystallization screen kits has become the most popular way of determining the preliminary crystallization conditions for macromolecules. In this study, the efficiency of three commercial screening kits, Crystal Screen and Crystal Screen 2 (Hampton Research), Wizard Screens I and II (Emerald BioStructures) and Personal Structure Screens 1 and 2 (Molecular Dimensions), has been compared using a set of 19 diverse proteins. 18 proteins yielded crystals using at least one crystallization screen. Surprisingly, Crystal Screens and Personal Structure Screens showed dramatically different results, although most of the crystallization formulations are identical as listed by the manufacturers. Higher molecular weight polyethylene glycols and mixed precipitants were found to be the most effective precipitants in this study

    Breeding \u3cem\u3eLotus Australis\u3c/em\u3e Andrews for Low Cyanide Content

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    Lotus australis Andrews is a native perennial tetraploid legume (2n=4x=28) widely distributed throughout Australia (Figure 1). It is highly variable with 14 botanical varieties reported in the Australian Plant Name Index (http://www.anbg.gov.au). Despite broad adaptation within L. australis no cultivars have been developed for cultivation. One of the main barriers to cultivation is the reported cyanogenic nature of the species (Foulds, 1982), which makes it potentially toxic when plant cyanogenic glycosides are fully hydrolysed to form hydrogen cyanide (HCN). Foulds (1982) also reported that the cyanophoric trait was polymorphic at seedling and adult stages with 12% of plants acyanogenic in some populations. . The Cooperative Research Center for Plant-Based Management of Dryland Salinity, financially supported by Australian Wool Innovation has commenced a breeding program to develop a non-toxic cultivar of L. australis. The selection criterion of the first phase of the breeding programme was for low HCN production. Once this trait is stabilised, forage production and seed yield as well as general plant health will be the main breeding objectives

    Genetic recombination is targeted towards gene promoter regions in dogs

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    The identification of the H3K4 trimethylase, PRDM9, as the gene responsible for recombination hotspot localization has provided considerable insight into the mechanisms by which recombination is initiated in mammals. However, uniquely amongst mammals, canids appear to lack a functional version of PRDM9 and may therefore provide a model for understanding recombination that occurs in the absence of PRDM9, and thus how PRDM9 functions to shape the recombination landscape. We have constructed a fine-scale genetic map from patterns of linkage disequilibrium assessed using high-throughput sequence data from 51 free-ranging dogs, Canis lupus familiaris. While broad-scale properties of recombination appear similar to other mammalian species, our fine-scale estimates indicate that canine highly elevated recombination rates are observed in the vicinity of CpG rich regions including gene promoter regions, but show little association with H3K4 trimethylation marks identified in spermatocytes. By comparison to genomic data from the Andean fox, Lycalopex culpaeus, we show that biased gene conversion is a plausible mechanism by which the high CpG content of the dog genome could have occurred.Comment: Updated version, with significant revision
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