201 research outputs found

    Esca, BDA and Eutypiosis: foliar symptoms, trunk lesions and fungi observed in diseased vinestocks in two vineyards in Alsace

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    The French vineyard is affected by three principal wood diseases: Eutypa dieback, esca and black dead arm (BDA). Phaeomoniella chlamydospora, Phaeocremonium aleophilum, Eutypa lata, Fomitiporia mediterranea, Diplodia seriata, Diplodia mutila and Neofusicoccum parvum are the main fungi isolated in France and associated with grapevine trunk diseases. The aim of this study was to highlight the type of wood lesions and the fungus present in the Alsace vineyards (France) and to compare it with those identified in the other french vine-growing regions or with the German vineyards. Therefore, we have studied two vineyards with two different grapevine varieties ('Auxerrois', 'Gewürztraminer'). The foliar symptoms showed that the plots planted with 'Auxerrois' and 'Gewürztraminer' varieties had respectively 12 and 21 % grapevines with symptoms in 2005. Different cross sections were made on trunks and arms of 55 vines showing foliar symptoms, totalizing 162 microbiological isolations. Visual characterisations of the different lesions were described. The isolations made from the different necrosis showed the presence of species of fungi involved in grapevine trunk diseases and other fungi. Microbiological observations showed that for the Auxerrois vineyard the majority of the vines were infected with D. seriata, P. chlamydospora, E. lata and F. mediterranea. In the Gewürztraminer vineyard, the fungus most frequently isolated was P. chlamydospora, followed by D. seriata. The presence of D. seriata in different parts of the grapevine wood and in young wood is related to the severe damages observed on the vegetation.

    Conidia dispersal of Diplodia species  in a French vineyard

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    Diseases caused by species of Botryosphaeriaceae lead to significant losses of grape yield. Species in this family produce foliar symptoms similar to, but distinguishable from esca, and the diseases they cause are generally named black dead arm (BDA). Botryosphaeriaceae species are ascomycetes frequently isolated from grapevine stocks showing decline or dieback symptoms. It is therefore useful to know what is the spore dissemination period of Botryosphaeriaceae in the vineyard. The objective of this study was to determine the peak periods of conidial release by some Diplodia spp. in the Botryosphaeriaceae in grapevines and to ascertain the climatic factors that influence inoculum availability and dispersal. Spore dispersal from Vitis vinifera was studied from 2005 to 2006 in a French vineyard. Spores of Diplodia seriata and D.  mutila were trapped throughout the year. Spore release from D. seriata peaked during the vegetative growth period, while D. mutila  released its spores later

    Suppression of hidden order in URu2Si2 under pressure and restoration in magnetic field

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    We describe here recent inelastic neutron scattering experiments on the heavy fermion compound URu2Si2 realized in order to clarify the nature of the hidden order (HO) phase which occurs below T_0 = 17.5 K at ambient pressure. The choice was to measure at a given pressure P where the system will go, by lowering the temperature, successively from paramagnetic (PM) to HO and then to antiferromagnetic phase (AF). Furthermore, in order to verify the selection of the pressure, a macroscopic detection of the phase transitions was also achieved in situ via its thermal expansion response detected by a strain gauge glued on the crystal. Just above P_x = 0.5 GPa, where the ground state switches from HO to AF, the Q_0 = (1, 0, 0) excitation disappears while the excitation at the incommensurate wavevector Q_1 = (1.4, 0, 0) remains. Thus, the Q_0 = (1, 0, 0) excitation is intrinsic only in the HO phase. This result is reinforced by studies where now pressure and magnetic field HH can be used as tuning variable. Above P_x, the AF phase at low temperature is destroyed by a magnetic field larger than H_AF (collapse of the AF Q_0 = (1, 0, 0) Bragg reflection). The field reentrance of the HO phase is demonstrated by the reappearance of its characteristic Q_0 = (1, 0, 0) excitation. The recovery of a PM phase will only be achieved far above H_AF at H_M approx 35 T. To determine the P-H-T phase diagram of URu2Si2, macroscopic measurements of the thermal expansion were realized with a strain gauge. The reentrant magnetic field increases strongly with pressure. Finally, to investigate the interplay between superconductivity (SC) and spin dynamics, new inelastic neutron scattering experiments are reported down to 0.4 K, far below the superconducting critical temperature T_SC approx 1.3 K as measured on our crystal by diamagnetic shielding.Comment: 5 pages, 7 figures, ICN 2009 conference proceeding

    Field Reentrance of the Hidden Order State of URu2Si2 under Pressure

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    Combination of neutron scattering and thermal expansion measurements under pressure shows that the so-called hidden order phase of URu2Si2 reenters in magnetic field when antiferromagnetism (AF) collapses at H_AF (T). Macroscopic pressure studies of the HO-AF boundaries were realized at different pressures via thermal expansion measurements under magnetic field using a strain gauge. Microscopic proof at a given pressure is the reappearance of the resonance at Q_0=(1,0,0) under field which is correlated with the collapse of the AF Bragg reflections at Q_0.Comment: 5 pages, 6 figures, accepted for publication in J. Phys. Soc. Jp

    Why the hidden order in URu2Si2 is still hidden - one simple answer

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    For more than two decades, the nonmagnetic anomaly observed around 17.5 K in URu2Si2, has been investigated intensively. However, any kind of fingerprint for the lattice anomaly has not been observed. Therefore, the order has been called "the hidden order". One simple answer to why the hidden order is still hidden is presented from the space group analysis. The second order phase transition from I4/mmm (No. 139) to P4_2/mnm (No. 136) does not need any kind of lattice distortion in this system, and allows the NQR frequency at Ru-site unchanged. It is compatible with O_{xy}-type anti-ferro quadrupole ordering with Q=(0, 0, 1). The characteristics of the hidden order are discussed based on the local 5f^2 electron picture.Comment: Accepted for publication in J. Phys. Soc. Jpn., 4 pages, 2 figure

    The SLUGGS survey: the mass distribution in early-type galaxies within five effective radii and beyond

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    We study mass distributions within and beyond 5 effective radii (Re) in 23 early-type galaxies from the SAGES Legacy Unifying Globulars and Galaxies Survey, using their globular cluster (GC) kinematic data. The data are obtained with Keck/DEep Imaging Multi-Object Spectrograph, and consist of line-of-sight velocities for ̃3500 GCs, measured with a high precision of ̃15 km s-1 per GC and extending out to ̃13 Re. We obtain the mass distribution in each galaxy using the tracer mass estimator of Watkins et al. and account for kinematic substructures, rotation of the GC systems and galaxy flattening in our mass estimates. The observed scatter between our mass estimates and results from the literature is less than 0.2 dex. The dark matter fraction within 5 Re (fDM) increases from ̃0.6 to ̃0.8 for low- and high-mass galaxies, respectively, with some intermediate-mass galaxies (M* ̃ 1011 M☉) having low fDM ̃ 0.3, which appears at odds with predictions from simple galaxy models. We show that these results are independent of the adopted orbital anisotropy, stellar mass-to-light (M/L) ratio, and the assumed slope of the gravitational potential. However, the low fDM in the ̃1011 M☉ galaxies agrees with the cosmological simulations of Wu et al. where the pristine dark matter distribution has been modified by baryons during the galaxy assembly process. We find hints that these M* ̃ 1011 M☉ galaxies with low fDM have very diffuse dark matter haloes, implying that they assembled late. Beyond 5 Re, the M/L gradients are steeper in the more massive galaxies and shallower in both low and intermediate mass galaxies

    An expression signature of the angiogenic response in gastrointestinal neuroendocrine tumours: correlation with tumour phenotype and survival outcomes.

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    BACKGROUND: Gastroenteropancreatic neuroendocrine tumours (GEP-NETs) are heterogeneous with respect to biological behaviour and prognosis. As angiogenesis is a renowned pathogenic hallmark as well as a therapeutic target, we aimed to investigate the prognostic and clinico-pathological role of tissue markers of hypoxia and angiogenesis in GEP-NETs. METHODS: Tissue microarray (TMA) blocks were constructed with 86 tumours diagnosed from 1988 to 2010. Tissue microarray sections were immunostained for hypoxia inducible factor 1α (Hif-1α), vascular endothelial growth factor-A (VEGF-A), carbonic anhydrase IX (Ca-IX) and somatostatin receptors (SSTR) 1–5, Ki-67 and CD31. Biomarker expression was correlated with clinico-pathological variables and tested for survival prediction using Kaplan–Meier and Cox regression methods. RESULTS: Eighty-six consecutive cases were included: 51% male, median age 51 (range 16–82), 68% presenting with a pancreatic primary, 95% well differentiated, 51% metastatic. Higher grading (P=0.03), advanced stage (P<0.001), high Hif-1α and low SSTR-2 expression (P=0.03) predicted for shorter overall survival (OS) on univariate analyses. Stage, SSTR-2 and Hif-1α expression were confirmed as multivariate predictors of OS. Median OS for patients with SSTR-2+/Hif-1α-tumours was not reached after median follow up of 8.8 years, whereas SSTR-2-/Hif-1α+ GEP-NETs had a median survival of only 4.2 years (P=0.006). CONCLUSION: We have identified a coherent expression signature by immunohistochemistry that can be used for patient stratification and to optimise treatment decisions in GEP-NETs independently from stage and grading. Tumours with preserved SSTR-2 and low Hif-1α expression have an indolent phenotype and may be offered less aggressive management and less stringent follow up

    On the Hidden Order in URu2_{2}Si2_{2} --- Antiferro Hexadecapole Order and its Consequences

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    An antiferro ordering of an electric hexadecapole moment is discussed as a promising candidate for the long standing mystery of the hidden order phase in URu2_{2}Si2_{2}. Based on localized ff-electron picture, we discuss the rationale of the selected multipole and the consequences of the antiferro hexadecapole order of xy(x2y2)xy(x^{2}-y^{2}) symmetry. The mean-field solutions and the collective excitations from them explain reasonably significant experimental observations: the strong anisotropy in the magnetic susceptibility, characteristic behavior of pressure versus magnetic field or temperature phase diagrams, disappearance of inelastic neutron-scattering intensity out of the hidden order phase, and insensitiveness of the NQR frequency at Ru-sites upon ordering. A consistency with the strong anisotropy in the magnetic responses excludes all the multipoles in two-dimensional representations, such as (Oyz,Ozx)(O_{yz},O_{zx}). The expected azimuthal angle dependences of the resonant X-ray scattering amplitude are given. The (x2y2)(x^{2}-y^{2})-type antiferro quadrupole should be induced by an in-plane magnetic field along [110][110], which is reflected in the thermal expansion and the elastic constant of the transverse (c11c12)/2(c_{11}-c_{12})/2 mode. The (x2y2)(x^{2}-y^{2})-type [(xy)(xy)-type] antiferro quadrupole is also induced by applying the uniaxial stress along [110][110] direction [[100][100] direction]. A detection of these induced antiferro quadrupoles under the in-plane magnetic field or the uniaxial stress using the resonant X-ray scattering provides a direct redundant test for the proposed order parameter.Comment: 10 pages, 10 figures, 5 table

    Search for the Proton Decay Mode proton to neutrino K+ in Soudan 2

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    We have searched for the proton decay mode proton to neutrino K+ using the one-kiloton Soudan 2 high resolution calorimeter. Contained events obtained from a 3.56 kiloton-year fiducial exposure through June 1997 are examined for occurrence of a visible K+ track which decays at rest into mu+ nu or pi+ pi0. We found one candidate event consistent with background, yielding a limit, tau/B > 4.3 10^{31} years at 90% CL with no background subtraction.Comment: 13 pages, Latex, 3 tables and 3 figures, Accepted by Physics Letters
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