1,721,082 research outputs found
Bremsstrahlung emission spectrum for electron microprobe analysis
No full textA Fokker-Planck analytical solution for an electron beam which slows down in a 3D rectangular sample and thermalizes through electron-ion Coulomb interactions has been found. In absence of electron removal the stationary solution is a Maxwellian distribution and if removal is taken into account the solution exhibits a Maxwellian-like behavior at low energies and a nonMaxwellian behavior at higher energies. From the electron distribution function, the free-free emission Bremsstrahlung spectrum has been obtained analytically for unitary Gaunt factor and a first estimate of the continuum and discrete spectrum is presente
Studies on the Carpinus betulus decline in the historical garden of Villa Arese-Borromeo in Cesano Maderno
No full textIndagini micologiche sulla componente eumicetica del deperimento della quercia in Lombardia
No full textImpact of a security event at a TRIGA reactor
No full textThe aim of this work is the study of the impact of security-related events and their consequences for research reactors, with particular emphasis on the off-site effects. The study case is done for the ENEA-Casaccia TRIGA RC-1 research reactor near Rome. The RC-1 Safety Report includes three different safety-related accident scenarios, namely the insertion of a step of positive reactivity, the uncontrolled extraction of all control rods at start-up or during a power variation and the emptying of the reactor pool. None of these scenarios imply radioactive releases at all. In this work, the focus is instead the description of the worst case scenario related to a security event and its consequences. Several possible scenarios have been analysed, however, the physical protection measures deter intrusions and, as shown by the Safety Report, even sabotage actions with major effects such as, the emptying of the reactor pool have no consequences on the fuel integrity. For these reasons, the worst security-related scenario considered in this work is a large plane crash with the complete destruction of the reactor hall and the reactor core. Propagation of the source term to the environment and the effective dose calculations have been performed using RASCAL, HOTSPOT and GENII codes following the ICRP-60 standards
Further studies on the etiological agents of carpinus betulus decline
No full textATP-binding cassette (ABC) transporters are a large superfamily of proteins responsible for the ATP-dependent translocation of a wide variety of different en-dogenous and exogenous toxicants across cellular membranes. We used a PCR-based approach to isolate from Botrytis cinerea a DNA fragment that proved be an ABC type transporter gene following sequencing and Southern blot analyses. This gene, named BcatrO, was characterized by RT-PCR expression and knock-out mutant phenotype analysis. Treatment of B. cinerea with H2O2 and methyl viologen enhanced transcription of BcatrO. An increase of the gene transcripts was also observed in the early stages of pathogenesis after inoculation of the fungus to bean leaves. BcatrO knock-out mutants of B. cinerea were more sensitive than the wild type both to H2O2 and fungicide fenpiclonil, but displayed the same virulence. The possible role of BcatrO in a mechanism of resistance of B. cinerea to reactive oxygen species (ROS) or their products and in pleiotropic drug resistance phenomena is discussed
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