No abstract available

[en] The problem of relativistic Markov processes is considered inside the framework of the general program of extending Nelson stochastic mechanics to general dynamical systems. Therefore the processes considered here have connections with relativistic quantum mechanics, in particular with Feynman path integral formulation, in the same way as the generalized random fields of Euclidean field theory are connected with usual quantum field theory

[en] In this note we show how to apply the methods of an earlier paper (1978) in order to have the stochastic mechanics of a charged spinning particle interacting with a given electromagnetic field. We describe the inner degrees of freedom of the particle through the Su(2) group, this gives immediately a decomposition of the Schroedinger equation, arising in this particular case, into a family of Pauli-type equations for each spin. The interaction with the electromagnetic field is unable to change the spin of the particle, according with usual physical interpretation. Our formalism can represent the basis for a natural and rigorous introduction of Feynman-Kac path integrals for spinning particles (even for half-integer spins). (HSI/orig.)

[en] The methods of stochastic quantization are applied to the vector-meson field in the Proca formulation. The difficulties connected with the additional unphysical degrees of freedom are circumvented through a proper redefinition of the Lagrangian in terms of the physical fields. Stochastic equations, generalizing the classical canonical equations of motion, are found in agreement with the results already known for the scalar case and the electromagnetic case. Finally, the connection with the Euclidean-Markov theory is pointed out

[en] We show how to recover all the features of the Euclidean-Markov structure for the vector-meson field, starting from the stochastic quantization procedure

[en] Full text: Soil samples collected inside and outside an industrial polluted area of national environmental interest located in 'Val Basento' (Basilicata, Italy) have been studied by a combination of different advanced analytical techniques exploiting high intensity synchrotron generated x-rays. Mercury (Hg) concentration in the soil ranged from 1 up to 250 μg/g. Bulk EXAFS (Extended x-ray Absorption Fine Structure spectroscopy) and XANES (x-ray Absorption Near Edge Structure spectroscopy) were performed on soil samples sieved at 2 mm and on the clay fraction (< 2 μm), where the highest amount of Hg was concentrated. In addition to bulk XAS investigations, microanalyses on soil thin sections by combined μ-XRF/μ-XRD (micro x-ray fluorescence / micro x-ray diffraction) and μ- XANES, with a resolution from 10 to 20 μm, were also performed. μ-XRF maps were collected in order to localize microscopic Hg containing particles in areas of ca. 1 mm². Simultaneous to μ-XRF spectra, microdiffraction patterns were collected in each point of the maps, in order to identify any correlation between Hg and its mineralogical forms. Once points of interest were localized, μ-XANES spectra were collected and compared with the spectra of known Hg standard compounds. The combination of bulk XAS and microbeam measurements not only provide a detailed Hg speciation at the microscale level, enables better interpretation of the higher length bulk scale XAS spectra in the light of the more easily manageable information obtained from microanalyses. From this combined synchrotron x-ray spectroscopic investigation, we find that Hg was mainly speciated as HgS (cinnabar) and Hg(0) in the samples collected inside the industrial site and as Hg₂Cl₂, HgCl₂ and Hg bound to organic matter in the samples collected in the areas surrounding the industrial site. Quantification of the percentage of the various Hg forms in the soil samples was also obtained. This type of pollution is typical of industrial areas where chlor-alkali plants have been operating in the past. The detailed Hg speciation will allow for a better assessment of the environmental and human risk connected to Hg contamination of these soils, as well as to develop more effective remediation strategies for an environmental restoration of the area. (author)