139 research outputs found

    Critical phenomena from the two-particle irreducible 1/N expansion

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    The 1/N expansion of the two-particle irreducible (2PI) effective action is employed to compute universal properties at the second-order phase transition of an O(N)-symmetric N-vector model directly in three dimensions. At next-to-leading order the approach cures the spurious small-N divergence of the standard (1PI) 1/N expansion for a computation of the critical anomalous dimension eta(N), and leads to improved estimates already for moderate values of N.Comment: 18 pages, 3 figure

    Rice F-bZIP transcription factors regulate the zinc deficiency response

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    The F-bZIP transcription factors bZIP19 and bZIP23 are the central regulators of the zinc deficiency response in Arabidopsis, and phylogenetic analysis of F-bZIP homologs across land plants indicates that the regulatory mechanism of the zinc deficiency response may be conserved. Here, we identified the rice F-bZIP homologs and investigated their function. OsbZIP48 and OsbZIP50, but not OsbZIP49, complement the zinc deficiency-hypersensitive Arabidopsis bzip19bzip23 double mutant. Ectopic expression of OsbZIP50 in Arabidopsis significantly increases plant zinc accumulation under control zinc supply, suggesting an altered Zn sensing in OsbZIP50. In addition, we performed a phylogenetic analysis of F-bZIP homologs from representative monocot species that supports the branching of plant F-bZIPs into Group 1 and Group 2. Our results suggest that regulation of the zinc deficiency response in rice is conserved, with OsbZIP48 being a functional homolog of AtbZIP19 and AtbZIP23. A better understanding of the mechanisms behind the Zn deficiency response in rice and other important crops will contribute to develop plant-based strategies to address the problems of Zn deficiency in soils, crops, and cereal-based human diets.</p

    Talking quiescence: a rigorous theory that supports parallel composition, action hiding and determinisation

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    The notion of quiescence - the absence of outputs - is vital in both behavioural modelling and testing theory. Although the need for quiescence was already recognised in the 90s, it has only been treated as a second-class citizen thus far. This paper moves quiescence into the foreground and introduces the notion of quiescent transition systems (QTSs): an extension of regular input-output transition systems (IOTSs) in which quiescence is represented explicitly, via quiescent transitions. Four carefully crafted rules on the use of quiescent transitions ensure that our QTSs naturally capture quiescent behaviour. We present the building blocks for a comprehensive theory on QTSs supporting parallel composition, action hiding and determinisation. In particular, we prove that these operations preserve all the aforementioned rules. Additionally, we provide a way to transform existing IOTSs into QTSs, allowing even IOTSs as input that already contain some quiescent transitions. As an important application, we show how our QTS framework simplifies the fundamental model-based testing theory formalised around ioco.Comment: In Proceedings MBT 2012, arXiv:1202.582

    Publications on Clinical Research in Otolaryngologyā€“A Systematic Analysis of Leading Journals in 2010

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    Background: We wanted to asses and characterize the volume of Otolaryngology publications on clinical research, published in major journals.Methods and Material: To assess volume and study type of clinical research in Otolaryngology we performed a literature search in high impact factor journals. We included 10 high impact factor Otolaryngology journals and 20 high impact factor medical journals outside this field (2011). We extracted original publications and systematic reviews from 2010. Publications were classified according to their research question, that is therapy, diagnosis, prognosis or etiology.Results: From Otolaryngology journals (impact factor 1.8 to 2.8) we identified 694 (46%) publications on original observations and 27 (2%) systematic reviews. From selected medical journals (impact factor 6.0 to 101.8) 122 (2%) publications related to Otolaryngology, 102 (83%) were on original observations and 2 (0.04%) systematic reviews. The most common category was therapy (40%).Conclusion: Half of publications in Otolaryngology concerns clinical research, which is higher than other specialties. In medical journals outside the field of Otolaryngology, a small proportion (2%) of publications is related to Otolaryngology. Striking is that systematic reviews, which are considered high level evidence, make up for only 2% of publications. We must ensure an increase of clinical research for optimizing medical practice

    Ferromagnetic/superconducting proximity effect in La0.7Ca0.3MnO3 / YBa2Cu3O7 superlattices

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    We study the interplay between magnetism and superconductivity in high quality YBa2Cu3O7 (YBCO) / La0.7Ca0.3MnO3(LCMO)superlattices. We find evidence for the YBCO superconductivity depression in presence of the LCMO layers. We show that due to its short coherence length superconductivity survives in the YBCO down to much smaller thickness in presence of the magnetic layer than in low Tc superconductors. We also find that for a fixed thickness of the superconducting layer, superconductivity is depressed over a thickness interval of the magnetic layer in the 100 nm range. This is a much longer length scale than that predicted by the theory of ferromagnetic/superconducting proximity effect.Comment: 10 pages + 5 figures, submitted to Phys. Rev.

    Genetic analysis of morphological traits in a new, versatile, rapid-cycling Brassica rapa recombinant inbred line population

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    A recombinant inbred line (RIL) population was produced based on a wide cross between the rapid-cycling and self-compatible genotypes L58, a Caixin vegetable type, and R-o-18, a yellow sarson oil type. A linkage map based on 160 F7 lines was constructed using 100 Single nucleotide polymorphisms (SNPs), 130 AFLPĀ®, 27 InDel, and 13 publicly available SSR markers. The map covers a total length of 1150 centiMorgan (cM) with an average resolution of 4.3 cM/marker. To demonstrate the versatility of this new population, 17 traits, related to plant architecture and seed characteristics, were subjected to quantitative trait loci (QTL) analysis. A total of 47 QTLs were detected, each explaining between 6 and 54% of the total phenotypic variance for the concerned trait. The genetic analysis shows that this population is a useful new tool for analyzing genetic variation for interesting traits in B. rapa, and for further exploitation of the recent availability of the B. rapa whole genome sequence for gene cloning and gene function analysis

    Instrument description and performance of the Imaging Gamma-Ray Telescope COMPTEL aboard the Compton Gamma-Ray Observatory

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    The COMPTEL instrument aboard the COMPTEL Gamma-Ray Observatory and its performance capabilities are described. Calibration data are used to determine the angular and energy response, and the effective detection area. The imaging properties of COMPTEL are demonstrated, and the sensitivity of Comptel to celestial gamma-ray sources are estimated from flight data

    An overview of first results from COMPTEL

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    COMPTEL is the first imaging telescope to explore the MeV gamma-ray range (0.7 to 30 MeV). At present, it is performing a complete sky survey. Targets of special interest in the COMPTEL energy range are radio pulsars, X-ray binaries, novae, supernovae, supernova remnants, mulecular clouds, the interstellar medium within the Milky Way, active galactic nuclei, and the diffuse cosmic background radiation. The data from the first half year of the mission have demonstrated that COMPTEL performs as expected. The Crab is clearly seen at its proper position in the first images of the anticenter region of the galaxy. The Crab and Vela pulsar lightcurves have been measured with unprecedented accuracy. The quasars 3C273 and 3C279 have been seen for the first time at MeV energies. Both quasars show a break in their energy spectra in the COMPTEL energy range
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