Dynamical properties of dissipative XYZ Heisenberg lattices

We study dynamical properties of dissipative XYZ Heisenberg lattices where anisotropic spin-spin coupling competes with local incoherent spin flip processes. In particular, we explore a region of the parameter space where dissipative magnetic phase transitions for the steady state have been recently predicted by mean-field theories and exact numerical methods. We investigate the asymptotic decay rate towards the steady state both in 1D (up to the thermodynamical limit) and in finite-size 2D lattices, showing that critical dynamics does not occur in 1D, but it can emerge in 2D. We also analyze the behavior of individual homodyne quantum trajectories, which well reveal the nature of the transition

Tribological Properties of High-Speed Uniform Femtosecond Laser Patterning on Stainless Steel

In this work, an analysis of the tribological performance of laser-induced periodic surface structures (LIPSS) treated X5CrNi1810 stainless steel was conducted. The approach followed by authors was to generate LIPSS-patterned circular tracks, composed of radial straight grooves with uniform angular periodicity. This permitted to measure the tribological properties in a pin-on-flat configuration, keeping fixed the orientation between the grooves and the sliding direction. A Stribeck curve was measured, as well as the consequent wear. A deep analysis of the sub-surface conditions after LIPSS generation was moreover performed using Focused Ion Beam (FIB) cross-section

Covered self-expandable metal stents for pancreatic duct stricture: a systematic review and meta-analysis

Background and study aims Placement of a covered (C)-self-expandable metal stent (SEMS) has been recently investigated as an alternative endoscopic treatment for main pancreatic duct stricture (MPDS) in chronic pancreatitis. Our aim was to carry out a systematic review and meta-analysis of studies quantifying efficacy and safety of C-SEMSs in the management of MPDS.Methods A multiple database search was performed, including MEDLINE, Embase and Cochrane Library, from January 2000 to September 2020, to identify studies reporting the efficacy and safety of C-SEMSs in patients with MPDS. Stricture and pain resolution were investigated. Other outcomes included technical success, stent migration, stricture recurrence and need for repeated stent placement. Pancreatitis, severe abdominal pain requiring stent removal and de-novo stricture were recorded as complications.Results Nineteen studies were identified, which included a total of 300 patients. C-SEMSs showed a pooled stricture resolution rate of 91 % [95 % confidence interval (CI), 85 %-96 %] and a pooled pain resolution rate of 92 % (95 % CI, 85 %-98 %). The pooled proportion for stricture recurrence was equal to 6 % (95 % CI, 1 %-14 %), while stent migration occurred in 33 of 300 patients, the pooled proportion being 7 % (95 % CI 1 %-15 %). The pooled mean stent duration was 133 days (95 % CI, 100-166 days). The most common complication was pancreatitis (3 %, 95 % CI 0 %-8 %), while de-novo stricture pooled proportion was 2 % (95 % CI, 0 %-5 %).Conclusions C-SEMSs are effective and safe in the treatment of MPDS. However, there is a significant need for further high-quality, well-designed studies to produce evidence-based data on short and long-term efficacy, safety, costs of C-SEMSs, and also optimal stent duration

Improving Surgical Robotics Training with Haptic Virtual Fixtures: An Experimental Study

The lack of high-level assistive control strategies in the field of teleoperated surgical robots has been linked to intra-operative injuries and increased fatigue experienced by practitioners. Virtual Fixtures analogous to the one proposed in this study may be beneficial for the patient's safety and the outcome of the operation; this work aims at evaluating their effectiveness in the context of surgical training. Tracking the position and orientation of a teleoperated surgical instrument with respect to a reference trajectory - planned in the pre-operative phase - allows one to compute and apply feedback forces to the manipulators held by the practitioner, which will provide haptic guidance towards an improved surgical performance. This high-level control strategy is here tested on a suturing task emulated in a virtual environment, where a group of participants was evaluated on the distance and angle error committed during the execution with and without assistance. The assistive modality proposed here is able to reduce the average error committed in the execution of the virtual suturing task: virtual fixtures and other similar assistance mechanisms may be most beneficial in the surgical training scenario, improving the learning curve and achieving better performances

Classificazione della marginalità dei piccoli comuni del Piemonte 2009

Contributi di ricerca ; n.235/2009- Indice #6- Introduzione #8- I piccoli comuni del Piemonte #10- Marginalità socioeconomica #18- I risultati dell'analisi #30- Allegati #4

Classificazione della marginalità dei piccoli comuni del Piemonte 2008

Strumentires ; 12- Indice #3- Introduzione #9- I piccoli comuni del Piemonte #11- La marginalità socioeconomica #16- I risultati dell'analisi #32- Appendici #4

Magnetic characterization of cobalt nanowires and square nanorings fabricated by focused electron beam induced deposition

The magnetic properties of nanowires (NWs) and square nanorings, which were deposited by focused electron beam induced deposition (FEBID) of a Co carbonyl precursor, are studied using off-axis electron holography (EH), Lorentz transmission electron microscopy (L-TEM) and magnetic force microscopy (MFM). EH shows that NWs deposited using beam energies of 5 and 15 keV have the characteristics of magnetic dipoles, with larger magnetic moments observed for NWs deposited at lower energy. L-TEM is used to image magnetic domain walls in NWs and nanorings and their motion as a function of applied magnetic field. The NWs are found to have almost square hysteresis loops, with coercivities of ca. 10 mT. The nanorings show two different magnetization states: for low values of the applied in-plane field (0.02 T) a horseshoe state is observed using L-TEM, while for higher values of the applied in-plane field (0.3 T) an onion state is observed at remanence using L-TEM and MFM. Our results confirm the suitability of FEBID for nanofabrication of magnetic structures and demonstrate the versatility of TEM techniques for the study and manipulation of magnetic domain walls in nanostructures