Neutrinos: Dirac or Majorana?

The problem of the nature of the neutrino, namely i f it is a massless Dirac particle different from its antineutrino or a Majorana particle with finite mass, is discussed. The question is related to the recent results showing the presence of neutrino oscillations clearly indicating that the difference between the squared mass of neutrinos of different flavours is different from zero. Neutrinoless double beta decay (DBD) is at present the most powerful tool to determine the effective value of the mass of a Majorana neutrino. The results already obtained in this lepton violating process will be reported and the two pres ently running DBD experiments briefly discussed. The future second generation experiments will be reviewed with special emphasis to those already partially approved. In conclusion the peculiar and interdisciplinary nature of these searches will be stressed in their exciting aim to discover if neutrino is indeed a Majorana particl

Neutrino physics and my debts to Bruno

After a brief introduction on the important role played by Bruno Pontecorvo in my scientific life, mainly involved in neutrino physics, I will shortly report the subjects where I could particularly appreciate his greatness which particularly impressed me. I will therefore consider in more details double beta decay especially in its neutrinoless channel were I was and am particularly involved, weak neutral currents, solar neutrinos, neutrino oscillation, determination of the neutrino mass and one unusual research of mine to which Bruno was particularly interested

Neutrino physics and my debts to Bruno

After a brief introduction on the important role played by Bruno Pontecorvo in my scientific life, mainly involved in neutrino physics, I will shortly report the subjects where I could particularly appreciate his greatness which particularly impressed me. I will therefore consider in more details double beta decay especially in its neutrinoless channel were I was and am particularly involved, weak neutral currents, solar neutrinos, neutrino oscillation, determination of the neutrino mass and one unusual research of mine to which Bruno was particularly interested

Stochastic resonance in a suspension of magnetic dipoles under shear flow

We show that a magnetic dipole in a shear flow under the action of an oscillating magnetic field displays stochastic resonance in the linear response regime. To this end, we compute the classical quantifiers of stochastic resonance, i.e. the signal to noise ratio, the escape time distribution, and the mean first passage time. We also discuss limitations and role of the linear response theory in its applications to the theory of stochastic resonance.Comment: 17 pages, 5 figures, approved for publication in PR

Nucleon decay and atmospheric neutrinos in the Mont Blanc experiment

In the NUSEX experiment, during 2.8 years of operation, 31 fully contained events have been collected; 3 among them are nucleon decay candidates, while the others have been attributed to upsilon interactions. Limits on nucleon lifetime and determinations of upsilon interaction rates are presented

Real-time prediction of breast lesions displacement during Ultrasound scanning using a position-based dynamics approach.

Although ultrasound (US) images represent the most popular modality for guiding breast biopsy, they are sometimes unable to render malignant regions, thus preventing accurate lesion localization which is essential for a successful procedure. Biomechanical models can support the localization of suspicious areas identified on a pre-operative image during US scanning since they are able to account for anatomical deformations resulting from US probe pressure. We propose a deformation model which relies on position-based dynamics (PBD) approach to predict the displacement of internal targets induced by probe interaction during US acquisition. The PBD implementation available in NVIDIA FleX is exploited to create an anatomical model capable of deforming in real-time. In order to account for each patient\u2019s specificities, model parameters are selected as those minimizing the localization error of a US-visible landmark of the anatomy of interest (in our case, a realistic breast phantom). The updated model is used to estimate the displacement of other internal lesions due to probe-tissue interaction. The proposed approach is compared to a finite element model (FEM), generally used in breast biomechanics, and a rigid one. Localization error obtained when applying the PBD model remains below 11 mm for all the tumors even for input displacements in the order of 30 mm. The proposed method obtains results aligned with FE models with faster computational performance, suitable for real-time applications. In addition, it outperforms rigid model used to track lesion position in US-guided breast biopsies, at least halving the localization error for all the displacement ranges considered. Position-based dynamics approach has proved to be successful in modeling breast tissue deformations during US acquisition. Its stability, accuracy and real-time performance make such model suitable for tracking lesions displacement during US-guided breast biopsy

A position-based framework for the prediction of probe-induced lesion displacement in Ultrasound-guided breast biopsy

Although ultrasound (US) images represent the most popular modality for guiding breast biopsy, they are sometimes unable to render malignant regions, thus preventing accurate lesion localization which is essential for a successful procedure. Biomechanical models can support the localization of suspicious areas identified on a pre-operative image during US scanning since they are able to account for anatomical deformations resulting from US probe pressure. We propose a deformation model which relies on position-based dynamics (PBD) approach to predict the displacement of internal targets induced by probe interaction during US acquisition. The PBD implementation available in NVIDIA FleX is exploited to create an anatomical model capable of deforming online. Simulation parameters are initialized on a calibration phantom under different levels of probe-induced deformations, then they are fine-tuned by minimizing the localization error of a US-visible landmark of a realistic breast phantom. The updated model is used to estimate the displacement of other internal lesions due to probe-tissue interaction. The localization error obtained when applying the PBD model remains below 11 mm for all the tumors even for input displacements in the order of 30 mm. This approach outperforms rigid model used to track lesion position in US-guided breast biopsies, at least halving the localization error for all the displacement ranges considered. Position-based dynamics approach has proved to be successful in modeling breast tissue deformations during US acquisition. Its stability, accuracy and real-time performance make such model suitable for tracking lesions displacement during US-guided breast biopsy