Geometric expansion of the log-partition function of the anisotropic Heisenberg model

We study the asymptotic expansion of the log-partition function of the anisotropic Heisenberg model in a bounded domain as this domain is dilated to infinity. Using the Ginibre's representation of the anisotropic Heisenberg model as a gas of interacting trajectories of a compound Poisson process we find all the non-decreasing terms of this expansion. They are given explicitly in terms of functional integrals. As the main technical tool we use the cluster expansion method.Comment: 38 page

Phase transitions for PP-adic Potts model on the Cayley tree of order three

In the present paper, we study a phase transition problem for the $q$-state $p$-adic Potts model over the Cayley tree of order three. We consider a more general notion of $p$-adic Gibbs measure which depends on parameter \rho\in\bq_p. Such a measure is called {\it generalized $p$-adic quasi Gibbs measure}. When $\rho$ equals to $p$-adic exponent, then it coincides with the $p$-adic Gibbs measure. When $\rho=p$, then it coincides with $p$-adic quasi Gibbs measure. Therefore, we investigate two regimes with respect to the value of $|\rho|_p$. Namely, in the first regime, one takes $\rho=\exp_p(J)$ for some J\in\bq_p, in the second one $|\rho|_p<1$. In each regime, we first find conditions for the existence of generalized $p$-adic quasi Gibbs measures. Furthermore, in the first regime, we establish the existence of the phase transition under some conditions. In the second regime, when $|\r|_p,|q|_p\leq p^{-2}$ we prove the existence of a quasi phase transition. It turns out that if $|\r|_p<|q-1|_p^2<1$ and \sqrt{-3}\in\bq_p, then one finds the existence of the strong phase transition.Comment: 27 page

On the Material Constitutive Behavior of the Aortic Root in Patients with Transcatheter Aortic Valve Implantation

Background: Transcatheter aortic valve implantation (TAVI) is a minimally invasive procedure used to treat patients with severe aortic valve stenosis. However, there is limited knowledge on the material properties of the aortic root in TAVI patients, and this can impact the credibility of computer simulations. This study aimed to develop a non-invasive inverse approach for estimating reliable material constituents for the aortic root and calcified valve leaflets in patients undergoing TAVI. Methods: The identification of material parameters is based on the simultaneous minimization of two cost functions, which define the difference between model predictions and cardiac-gated CT measurements of the aortic wall and valve orifice area. Validation of the inverse analysis output was performed comparing the numerical predictions with actual CT shapes and post-TAVI measures of implanted device diameter. Results: A good agreement of the peak systolic shape of the aortic wall was found between simulations and imaging, with similarity index in the range in the range of 83.7% to 91.5% for n.20 patients. Not any statistical difference was observed between predictions and CT measures of orifice area for the stenotic aortic valve. After TAVI simulations, the measurements of SAPIEN 3 Ultra (S3) device diameter were in agreement with those from post-TAVI angio-CT imaging. A sensitivity analysis demonstrated a modest impact on the S3 diameters when altering the elastic material property of the aortic wall in the range of inverse analysis solution. Conclusions: Overall, this study demonstrates the feasibility and potential benefits of using non-invasive imaging techniques and computational modeling to estimate material properties in patients undergoing TAVI

Classification, characterization and management of radioactive waste in Italy

Radioactive waste produced in Italy belongs to two main categories according to production routes. These are radioactive waste generated from the nuclear fuel cycle and those radioactive waste deriving from non-electronuclear activities, i.e., from nuclear medicine activities, industrial, and scientific research. The latter are responsibility of the Integrated Service for the management of radioactive waste: a group of authorized Operators supervised by ENEA (Italian National Agency for New Technologies, Energy and Sustainable Economic Development). In this paper, the Italian regulatory framework, the classification of radioactive waste and the most used characterization techniques, both destructive and nondestructive, are outlined

Uterine mesenchymal tumors: development and preliminary results of a magnetic resonance imaging (MRI) diagnostic algorithm

Purpose: The aim of our study is to propose a diagnostic algorithm to guide MRI findings interpretation and malignancy risk stratification of uterine mesenchymal masses with a multiparametric step-by-step approach. Methods: A non-interventional retrospective multicenter study was performed: Preoperative MRI of 54 uterine masses was retrospectively evaluated. Firstly, the performance of MRI with monoparametric and multiparametric approach was assessed. Reference standard for final diagnosis was surgical pathologic result (n = 53 patients) or at least 1-year MR imaging follow-up (n = 1 patient). Subsequently, a diagnostic algorithm was developed for MR interpretation, resulting in a Likert score from 1 to 5 predicting risk of malignancy of the uterine lesion. The accuracy and reproducibility of the MRI scoring system were then tested: 26 preoperative pelvic MRI were double-blind evaluated by a senior (SR) and junior radiologist (JR). Diagnostic performances and the agreement between the two readers with and without the application of the proposed algorithm were compared, using histological results as standard reference. Results: Multiparametric approach showed the best diagnostic performance in terms of accuracy (94.44%,) and specificity (97.56%). DWI was confirmed as the most sensible parameter with a relative high specificity: low ADC values (mean 0.66) significantly correlated to uterine sarcomas diagnosis (p &lt; 0.01). Proposed algorithm allowed to improve both JR and SR performance (algorithm-aided accuracy 88.46% and 96%, respectively) and determined a significant increase in inter-observer agreement, helping even the less-experienced radiologist in this difficult differential diagnosis. Conclusions: Uterine leiomyomas and sarcomas often show an overlap of clinical and imaging features. The application of a diagnostic algorithm can help radiologists to standardize their approach to a complex myometrial mass and to easily identify suspicious MRI features favoring malignancy

In-hospital and thirty-day outcomes of the SAPIEN 3 Ultra balloon-expandable transcatheter aortic valve : the S3U registry

Aims: The aim of this study was to evaluate 30-day safety and efficacy outcomes of transcatheter aortic valve implantation (TAVI) performed with the SAPIEN 3 Ultra system. Methods and results: The S3U registry is a physician-led, post-approval, multicentre, observational registry of transfemoral TAVI with the SAPIEN 3 Ultra. New features include an improved sealing skirt, a 14 Fr expandable sheath and a new delivery catheter. Overall, 139 consecutive patients at nine participating centres were enrolled. Mean age was 81.4 +/- 8.3 years, average STS score 3.8 +/- 2.4%. The vast majority (97.2%) underwent TAVI with local anaesthesia (28.8%) or conscious sedation (68.3%). Balloon predilatation was performed in 30 patients (21.6%), post-dilatation in three (2.2%). In-hospital, there were no cases of death, stroke, or conversion to open heart surgery. Major vascular complications occurred in three patients (2.2%), as well as major or life-threatening bleedings in three patients (2.2%). There were two moderate (1.4%) and no moderate/severe paravalvular leaks. Median length of stay after TAVI was three days (IQR 3-5 days). At 30 days, there were no deaths, MI, or strokes, and the incidence of new permanent pacemaker implantation was 4.4%. Conclusions: This first multicentre international experience of transfemoral TAVI with the SAPIEN 3 Ultra transcatheter heart valve shows good in-hospital and 30-day clinical outcomes.Peer reviewe

A new cupressaceous wood from the Lower Cretaceous of central Patagonia reveals possible clonal growth habit

A new genus and species, Austrocupressinoxylon barcinense, based on remains of cupressaceous wood is described for the Lower Cretaceous of central Patagonia, Argentina. The studied specimens are silicified fragments of picnoxylic and homoxylic wood that exhibit a combination of characters not previously reported, therefore a new genus is erected. The characters are: 1- growth ring boundaries distinct, 2- transition from earlywood to latewood gradual, 3- axial parenchyma diffuse,4- radial tracheid pitting predominantly abietinean,5- cross-field pitting cupressoid, arranged in both cupressoid and araucarioid patterns, 6- rays uniseriate heterocellular, 7- end and horizontal walls of ray parenchyma cells smooth or slightly nodular, and 8- ray tracheids with smooth walls. The cross-field pitting patterns and the presence of ray tracheids are two traits of particular interest in the context of systematic affinities. The fragments were collected from two stumps found in life position attached to each other by a main root, consequently, the disposition of the stumps suggests a case of clonal growth by root suckering. This is the second report of such mechanisms in the fossil records worldwide and the first one for South America.Facultad de Ciencias Naturales y Muse

Nuclear Analyses for the Assessment of the Loads on the ITER Radial Neutron Camera In-Port System and Evaluation of Its Measurement Performances

The radial neutron camera (RNC) is a key ITER diagnostic system designed to measure the uncollided 14- and 2.5-MeV neutrons from deuterium-tritium (DT) and deuterium-deuterium (DD) fusion reactions, through an array of detectors covering a full poloidal plasma section along collimated lines of sight (LoS). Its main objective is the assessment of the neutron emissivity/alpha source profile and the total neutron source strength, providing spatially resolved measurements of several parameters needed for fusion power estimation, plasma control, and plasma physics studies. The present RNC layout is composed of two fan-shaped collimating structures viewing the plasma radially through vertical slots in the diagnostic shielding module (DSM) of ITER Equatorial Port 1 (EP01): the ex-port subsystem and the in-port one. The ex-port subsystem, devoted to the plasma core coverage, extends from the Port Interspace to the Bioshield Plug: it consists of a massive shielding unit hosting two sets of collimators lying on different toroidal planes, leading to a total of 16 interleaved LoS. The in-port system consists of a cassette, integrated inside the port plug DSM, containing two detectors per each of the six LoS looking at the plasma edges. The in-port system must guarantee the required measurement performances in critical operating conditions in terms of high radiation levels, given its proximity to the plasma neutron source. This article presents an updated neutronic analysis based on the latest design of the in-port system and port plug. It has been performed by means of the Monte Carlo MCNP code and provides nuclear loads on the in-port RNC during normal operating conditions (NOC) and inputs for the measurement performance analysis