434 research outputs found

    Charge density waves and Fermi surface reconstruction in the clean overdoped cuprate superconductor Tl2Ba2CuO6+δ.

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    Hall effect and quantum oscillation measurements on high temperature cuprate superconductors show that underdoped compositions have small Fermi surface pockets whereas when heavily overdoped, a single much larger pocket is found. The origin of this change in electronic structure has been unclear, but may be related to the high temperature superconductivity. Here we show that the clean overdoped single-layer cuprate Tl2Ba2CuO6+δ (Tl2201) displays CDW order with a remarkably long correlation length ξ ≈ 200 Å which disappears above a hole doping of pCDW ≈ 0.265. We show that the evolution of the electronic properties of Tl2201 as the doping is lowered may be explained by a Fermi surface reconstruction which accompanies the emergence of the CDW below pCDW. Our results demonstrate importance of CDW correlations in understanding the electronic properties of overdoped cuprates

    Bioavailability, Antipsoriatic Efficacy and Tolerability of a New Light Cream with Mometasone Furoate 0.1%

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    Mometasone furoate, a potent glucocorticoid (class III) with a favorable benefit/risk ratio, has emerged as a standard medication for the treatment of inflammatory skin disorders. The purpose of the investigation presented here was to determine the noninferiority of a topical mometasone formulation, a light cream (O/W 60/40 emulsion) with mometasone furoate 0.1% (water content of 33%) versus marketed comparators. Using the vasoconstrictor assay, a strong blanching effect of the new cream (called Mometasone cream) comparable to that of a mometasone comparator, a fatty cream with mometasone furoate 0.1%, could be demonstrated. Thus, the topical bioavailability of the active ingredient mometasone furoate (0.1%) was regarded to be similar for Mometasone cream and the mometasone comparator. Using the psoriasis plaque test, a strong antipsoriatic effect comparable to that of the mometasone comparator was found for Mometasone cream after 12 days of occlusive treatment. A nearly identical reduction in the mean infiltrate thickness and similar mean AUC values were noted with both formulations confirmed by clinical assessment data. The noninferiority of Mometasone cream to its active comparator with re-spect to the AUC of change to baseline in infiltrate thickness was demonstrated. Both medications were well tolerated. Overall, Mometasone cream and the mometasone comparator showed similar efficacy and tolerability. Mometasone cream, in addition to its high potency and good tolerability, provides the properties of a light cream, which might make this new medication particularly suitable for application on acutely inflamed and sensitive skin. Copyright (C) 2012 S. Karger AG, Base

    Charge density waves and Fermi surface reconstruction in the clean overdoped cuprate superconductor Tl2Ba2CuO6+δ.

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    Hall effect and quantum oscillation measurements on high temperature cuprate superconductors show that underdoped compositions have small Fermi surface pockets whereas when heavily overdoped, a single much larger pocket is found. The origin of this change in electronic structure has been unclear, but may be related to the high temperature superconductivity. Here we show that the clean overdoped single-layer cuprate Tl2Ba2CuO6+δ (Tl2201) displays CDW order with a remarkably long correlation length ξ ≈ 200 Å which disappears above a hole doping of pCDW ≈ 0.265. We show that the evolution of the electronic properties of Tl2201 as the doping is lowered may be explained by a Fermi surface reconstruction which accompanies the emergence of the CDW below pCDW. Our results demonstrate importance of CDW correlations in understanding the electronic properties of overdoped cuprates

    Impacts of climate change on plant diseases – opinions and trends

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    There has been a remarkable scientific output on the topic of how climate change is likely to affect plant diseases in the coming decades. This review addresses the need for review of this burgeoning literature by summarizing opinions of previous reviews and trends in recent studies on the impacts of climate change on plant health. Sudden Oak Death is used as an introductory case study: Californian forests could become even more susceptible to this emerging plant disease, if spring precipitations will be accompanied by warmer temperatures, although climate shifts may also affect the current synchronicity between host cambium activity and pathogen colonization rate. A summary of observed and predicted climate changes, as well as of direct effects of climate change on pathosystems, is provided. Prediction and management of climate change effects on plant health are complicated by indirect effects and the interactions with global change drivers. Uncertainty in models of plant disease development under climate change calls for a diversity of management strategies, from more participatory approaches to interdisciplinary science. Involvement of stakeholders and scientists from outside plant pathology shows the importance of trade-offs, for example in the land-sharing vs. sparing debate. Further research is needed on climate change and plant health in mountain, boreal, Mediterranean and tropical regions, with multiple climate change factors and scenarios (including our responses to it, e.g. the assisted migration of plants), in relation to endophytes, viruses and mycorrhiza, using long-term and large-scale datasets and considering various plant disease control methods

    X-Ray Spectroscopy of Stars

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    (abridged) Non-degenerate stars of essentially all spectral classes are soft X-ray sources. Low-mass stars on the cooler part of the main sequence and their pre-main sequence predecessors define the dominant stellar population in the galaxy by number. Their X-ray spectra are reminiscent, in the broadest sense, of X-ray spectra from the solar corona. X-ray emission from cool stars is indeed ascribed to magnetically trapped hot gas analogous to the solar coronal plasma. Coronal structure, its thermal stratification and geometric extent can be interpreted based on various spectral diagnostics. New features have been identified in pre-main sequence stars; some of these may be related to accretion shocks on the stellar surface, fluorescence on circumstellar disks due to X-ray irradiation, or shock heating in stellar outflows. Massive, hot stars clearly dominate the interaction with the galactic interstellar medium: they are the main sources of ionizing radiation, mechanical energy and chemical enrichment in galaxies. High-energy emission permits to probe some of the most important processes at work in these stars, and put constraints on their most peculiar feature: the stellar wind. Here, we review recent advances in our understanding of cool and hot stars through the study of X-ray spectra, in particular high-resolution spectra now available from XMM-Newton and Chandra. We address issues related to coronal structure, flares, the composition of coronal plasma, X-ray production in accretion streams and outflows, X-rays from single OB-type stars, massive binaries, magnetic hot objects and evolved WR stars.Comment: accepted for Astron. Astrophys. Rev., 98 journal pages, 30 figures (partly multiple); some corrections made after proof stag

    A Two-Gene Balance Regulates Salmonella Typhimurium Tolerance in the Nematode Caenorhabditis elegans

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    Lysozymes are antimicrobial enzymes that perform a critical role in resisting infection in a wide-range of eukaryotes. However, using the nematode Caenorhabditis elegans as a model host we now demonstrate that deletion of the protist type lysozyme LYS-7 renders animals susceptible to killing by the fatal fungal human pathogen Cryptococcus neoformans, but, remarkably, enhances tolerance to the enteric bacteria Salmonella Typhimurium. This trade-off in immunological susceptibility in C. elegans is further mediated by the reciprocal activity of lys-7 and the tyrosine kinase abl-1. Together this implies a greater complexity in C. elegans innate immune function than previously thought

    First observations of separated atmospheric nu_mu and bar{nu-mu} events in the MINOS detector

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    The complete 5.4 kton MINOS far detector has been taking data since the beginning of August 2003 at a depth of 2070 meters water-equivalent in the Soudan mine, Minnesota. This paper presents the first MINOS observations of nuµ and [overline nu ]µ charged-current atmospheric neutrino interactions based on an exposure of 418 days. The ratio of upward- to downward-going events in the data is compared to the Monte Carlo expectation in the absence of neutrino oscillations, giving Rup/downdata/Rup/downMC=0.62-0.14+0.19(stat.)±0.02(sys.). An extended maximum likelihood analysis of the observed L/E distributions excludes the null hypothesis of no neutrino oscillations at the 98% confidence level. Using the curvature of the observed muons in the 1.3 T MINOS magnetic field nuµ and [overline nu ]µ interactions are separated. The ratio of [overline nu ]µ to nuµ events in the data is compared to the Monte Carlo expectation assuming neutrinos and antineutrinos oscillate in the same manner, giving R[overline nu ][sub mu]/nu[sub mu]data/R[overline nu ][sub mu]/nu[sub mu]MC=0.96-0.27+0.38(stat.)±0.15(sys.), where the errors are the statistical and systematic uncertainties. Although the statistics are limited, this is the first direct observation of atmospheric neutrino interactions separately for nuµ and [overline nu ]µ
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