47,748 research outputs found
Real-time reverse transcription polymerase chain reaction development for rapid detection of Tomato brown rugose fruit virus and comparison with other techniques
Background: Tomato brown rugose fruit virus (ToBRFV) is a highly infectious tobamovirus that causes severe disease in tomato (Solanum lycopersicum L.) crops. In Italy, the first ToBRFV outbreak occurred in 2018 in several provinces of the Sicily region. ToBRFV outbreak represents a serious threat for tomato crops in Italy and the Mediterranean Basin. Methods: Molecular and biological characterisation of the Sicilian ToBRFV ToB-SIC01/19 isolate was performed, and a sensitive and specific Real-time RT-PCR TaqMan minor groove binder probe method was developed to detect ToBRFV in infected plants and seeds. Moreover, four different sample preparation procedures (immunocapture, total RNA extraction, direct crude extract and leaf-disk crude extract) were evaluated. Results: The Sicilian isolate ToB-SIC01/19 (6,391 nt) showed a strong sequence identity with the isolates TBRFV-P12-3H and TBRFV-P12-3G from Germany, Tom1-Jo from Jordan and TBRFV-IL from Israel. The ToB-SIC01/19 isolate was successfully transmitted by mechanical inoculations in S. lycopersicum L. and Capsicum annuum L., but no transmission occurred in S. melongena L. The developed real-time RT-PCR, based on the use of a primer set designed on conserved sequences in the open reading frames3, enabled a reliable quantitative detection. This method allowed clear discrimination of ToBRFV from other viruses belonging to the genus Tobamovirus, minimising false-negative results. Using immunocapture and total RNA extraction procedures, the real-time RT-PCR and end-point RT-PCR gave the same comparable results. Using direct crude extracts and leaf-disk crude extracts, the end-point RT-PCR was unable to provide a reliable result. This developed highly specific and sensitive real-time RT-PCR assay will be a particularly valuable tool for early ToBRFV diagnosis, optimising procedures in terms of costs and time
The Earth Mantle-Core Effect in Matter-Induced Asymmetries for Atmospheric Neutrino Oscillations
Earth medium effects in the three-neutrino oscillations of atmospheric
neutrinos are observable under appropriate conditions. This paper generalizes
the study of the medium effects and the possibility of their observation in the
atmospheric neutrino oscillations from the case of neutrinos traversing only
the Earth mantle, where the density is essentially constant, to the case of
atmospheric neutrinos crossing also the Earth core. In the latter case new
resonance-like effects become apparent. We calculate the CPT-odd asymmetry for
the survival probability of muon neutrinos and the observable muon-charge
asymmetry, taking into account the different atmospheric neutrino fluxes, and
show the dependence of these asymmetries on the sign of
and on the magnitude of the mixing angle . A magnetized detector
with a sufficiently good neutrino momentum resolution is required for the
observation of the muon-charge asymmetry generated by the Earth mantle-core
effect.Comment: 14 pages, 5 figure
Inversion mechanism for the transport current in type-II superconductors
The longitudinal transport problem (the current is applied parallel to some
bias magnetic field) in type-II superconductors is analyzed theoretically.
Based on analytical results for simplified configurations, and relying on
numerical studies for general scenarios, it is shown that a remarkable
inversion of the current flow in a surface layer may be predicted under a wide
set of experimental conditions. Strongly inhomogeneous current density
profiles, characterized by enhanced transport toward the center and reduced, or
even negative, values at the periphery of the conductor, are expected when the
physical mechanisms of flux depinning and consumption (via line cutting) are
recalled. A number of striking collateral effects, such as local and global
paramagnetic behavior, are predicted. Our geometrical description of the
macroscopic material laws allows a pictorial interpretation of the physical
phenomena underlying the transport backflow.Comment: 8 pages, 6 figures (Best quality pictures are available by author's
contact
Sterile neutrino decay and the LSND experiment
We propose a new explanation of the intriguing LSND evidence for electron
antineutrino appearance in terms of heavy (mostly sterile) neutrino decay via a
coupling with a light scalar and light (mostly active) neutrinos. We perform a
fit to the LSND data, as well as all relevant null-result experiments, taking
into account the distortion of the spectrum due to decay. By requiring a
coupling g ~ 10^{-5}, a heavy neutrino mass m_4 ~ 100 keV and a mixing with
muon neutrinos |U_{mu 4}|^2 ~ 10^{-2}, we show that this model explains all
existing data evading constraints that disfavor standard (3+1) neutrino models.Comment: 3pp. Talk given at 9th International Conference on Astroparticle and
Underground Physics (TAUP 2005), Zaragoza, Spain, 10-14 Sep 200
Instability of Amorphous Ru-Si-O Thin Films under Thermal Oxidation
Ternary films about 200 nm thick of composition Ru20Si15O65 have been synthesized by reactive rf magnetron sputtering of a Ru1Si1 target in an argon-oxygen gas. As-deposited, the films are X-ray-amorphous. Their atomic density is 8.9 × 10^22/cm^3 (5.1 g/cm^3), and their electrical resistivity is in the range of 2 mOmega cm. After annealing in dry oxygen at 600°C for 30 min, micron-sized grains of RuO2 grow out of the film and volatile RuO4 escapes. The significance of these results is discussed
Dynamical magnetic anisotropy and quantum phase transitions in a vibrating spin-1 molecular junction
We study the electronic transport through a spin-1 molecule in which
mechanical stretching produces a magnetic anisotropy. In this type of device, a
vibron mode along the stretching axis will couple naturally to the molecular
spin. We consider a single molecular vibrational mode and find that the
electron-vibron interaction induces an effective correction to the magnetic
anisotropy that shifts the ground state of the device toward a non-Fermi liquid
phase. A transition into a Fermi liquid phase could then be achieved, by means
of mechanical stretching, passing through an underscreened spin-1 Kondo regime.
We present numerical renormalization group results for the differential
conductance, the spectral density, and the magnetic susceptibility across the
transition.Comment: 7 pages, 7 figure
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