0000000000999835
AUTHOR
D. Gurrera
Moving across the static magnetic field of a 1.5 T MRI scanner: Analysing compliance with Directive 2013/35/EU
Abstract Does the exposure of magnetic resonance imaging personnel to static magnetic fields fully comply with Directive 2013/35/EU? Despite the obligation to satisfy this question, a general answer cannot be provided, nor are final satisfying good practices methods for exposure assessment currently available. In order to contribute to fix this problem, three different 1.5 T scanners are analysed and – by a new theoretical insight – a positive answer is provided.
Signature of quantum interferences in above-threshold detachment of negative ions by a short infrared pulse
Numerical calculations of photodetachment of ${\mathrm{F}}^{\ensuremath{-}}$ irradiated by a linearly polarized strong short infrared pulse have been performed by evaluating the photoelectron ejection probability in the framework of a Keldysh-type approach modified to account for the temporal behavior of the pulse. The results of the calculations are in good agreement with measurements of energy spectra recently appearing in literature, and show features that may be explained in terms of quantum interferences in time domain.
Stochastic models for wind speed forecasting
Abstract This paper is concerned with the problem of developing a general class of stochastic models for hourly average wind speed time series. The proposed approach has been applied to the time series recorded during 4 years in two sites of Sicily, a region of Italy, and it has attained valuable results in terms both of modelling and forecasting. Moreover, the 24 h predictions obtained employing only 1-month time series are quite similar to those provided by a feed-forward artificial neural network trained on 2 years data.
Accomplishing the requirements within the new decree 159/2016: Comparative study of eddy currents induced in a human phantom moving near different MRI scanners
Purpose. In order to provide adequate risk-reducing procedures for MRI personnel (radiographers, anaesthetists, physicists, nurses, technicians, cleaners, etc.), different studies have been developed in the past years. Further to those, in the present work risk assessment concerned with currents induced by non-uniform static magnetic fields in MRI operators performing different tasks in prox imity of the scanner has been investigated across a set of different 1.5 T MRI scanners. Methods. The first step has been to empirically map the magnetic field around the different scanners and to select a proper adult human body as a heterogeneous volume conductor model. Then, upon observing the way ta…
Analysis and modeling of wind directions time series
This work aims at studying some aspects of wind directions in Italy and supplying appropriate models. A comparison is presented between independent mixture and Hidden Markov models, which seem to be appropriate as far as the series we studied.
34. Accomplishing the requirements within the new decree 159/2016: Comparative study of eddy currents induced in a human phantom moving near different MRI scanners
Purpose In order to provide adequate risk-reducing procedures for MRI personnel (radiographers, anaesthetists, physicists, nurses, technicians, cleaners, etc.), different studies have been developed in the past years. Further to those, in the present work risk assessment concerned with currents induced by non-uniform static magnetic fields in MRI operators performing different tasks in proximity of the scanner has been investigated across a set of different 1.5 T MRI scanners. Methods The first step has been to empirically map the magnetic field around the different scanners and to select a proper adult human body as a heterogeneous volume conductor model. Then, upon observing the way tasks…
Moving inside a MRI room: A risk assessment analysis
Moving across the stray magnetic field generated by a medical magnetic resonance imaging system may induce electric stimulation near or even beyond the threshold of physiological significance and adequate risk-reducing procedures for the involved personnel may be re quired. With this in mind, a set of different scanners has been analysed. Results suggest that a 1.5 T magnet may be expected in general to comply with the requirements of the currently in force European Electromagnetic Fields Directive for ensuring the health and safety of workers.
Taxonomy of correlations of wind velocity;an application to the Sicilian area.
Abstract We present an algorithm that allows us to analyze the cross-correlation of wind velocity measured in different locations; this algorithm is applied to 29 recording stations in Sicily. The results show that such correlations present a significant and persistent ultrametric structure that is influenced by the geographical neighborhood as well as by the presence of mountain and the sea. The algorithm presented, that is also able to reveal weak correlations, can be used as a starting point for the development of multivariate models of wind.
Univariate and multivariate properties of wind velocity time series
We analyze the time series of hourly average wind speeds measured at 29 different stations located in Sicily, a region with a complex morphology. The investigation, performed from the univariate as well as the multivariate point of view, evidences that the statistical properties of wind at the single sites have features that are not reproduced by standard models and, thus, require specific modeling. Moreover, the synchronous evolution of wind velocity presents a cluster structure, obtained with different algorithms, that persists in the standard deviation too.