Asymptotics of the solutions of the stochastic lattice wave equation

We consider the long time limit theorems for the solutions of a discrete wave equation with a weak stochastic forcing. The multiplicative noise conserves the energy and the momentum. We obtain a time-inhomogeneous Ornstein-Uhlenbeck equation for the limit wave function that holds both for square integrable and statistically homogeneous initial data. The limit is understood in the point-wise sense in the former case, and in the weak sense in the latter. On the other hand, the weak limit for square integrable initial data is deterministic

Thermal conductivity in harmonic lattices with random collisions

We review recent rigorous mathematical results about the macroscopic behaviour of harmonic chains with the dynamics perturbed by a random exchange of velocities between nearest neighbor particles. The random exchange models the effects of nonlinearities of anharmonic chains and the resulting dynamics have similar macroscopic behaviour. In particular there is a superdiffusion of energy for unpinned acoustic chains. The corresponding evolution of the temperature profile is governed by a fractional heat equation. In non-acoustic chains we have normal diffusivity, even if momentum is conserved.Comment: Review paper, to appear in the Springer Lecture Notes in Physics volume "Thermal transport in low dimensions: from statistical physics to nanoscale heat transfer" (S. Lepri ed.

Superdiffusion of energy in Hamiltonian systems perturbed by a conservative noise

We review some recent results on the anomalous diffusion of energy in systems of 1D coupled oscillators and we revisit the role of momentum conservation.Comment: Proceedings of the conference PSPDE 2012 https://sites.google.com/site/meetingpspde

Hydrodynamic limit for the velocity flip model

We study the diffusive scaling limit for a chain of $N$ coupled oscillators. In order to provide the system with good ergodic properties, we perturb the Hamiltonian dynamics with random flips of velocities, so that the energy is locally conserved. We derive the hydrodynamic equations by estimating the relative entropy with respect to the local equilibrium state modified by a correction term

LCC analysis for glued laminated timber components exposed in external

The aim of the experimentation is to characterize the performances of glued laminated timber components exposed to atmospheric agents, in the light of the concept of Life Cycle Cost, particularly emphasized in the Italian new legislation on public works. In fact, it could be seen that the design of the construction details and the initial characteristics of glue laminated timber components, require a particular attention to avoid errors that may undermine the possibility to perform the structural functions for which, above all, this material it is dedicated. The experimentation consisted of a series of tests aimed to identify the performance of glued laminated timber beams taken in site, after a work executed some years ago on a theatre built in Roman era, and to compare them with similarly manufactured new elements. The tests performed were thermography, ultrasound, Wood-Pecker penetrometer, mechanical characterization. The results will be used to begin setting limits and conditions for outdoor use of glue laminated timber, and assume a reliable life cycle, and consequently identify the most appropriate maintenance strategy for the LCC

Thermal conductivity of the Toda lattice with conservative noise

We study the thermal conductivity of the one dimensional Toda lattice perturbed by a stochastic dynamics preserving energy and momentum. The strength of the stochastic noise is controlled by a parameter $\gamma$. We show that heat transport is anomalous, and that the thermal conductivity diverges with the length $n$ of the chain according to $\kappa(n) \sim n^\alpha$, with $0 < \alpha \leq 1/2$. In particular, the ballistic heat conduction of the unperturbed Toda chain is destroyed. Besides, the exponent $\alpha$ of the divergence depends on $\gamma$

Cinacalcet is effective in relapses of secondary hyperparathyroidism after parathyroidectomy

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The frail world of haemodialysis patients in the COVID-19 pandemic era: a systematic scoping review

Background: Patients undergoing in-centre haemodialysis (HD) are particularly exposed to the dire consequences of COVID-19. The present systematic scoping review aims to identify the extent, range, and nature of articles related to COVID-19 and maintenance HD: it reports specifically the prevalence of the COVID-19 pandemic in the HD population, implementation of strategies for the prevention, mitigation and containment of the COVID-19 pandemic in HD centres, demographic and clinical characteristics, and outcomes of the pediatric and adult HD patients. Methods: A multi-step systematic search of the literature in Pubmed, Scopus, Ovid Medline, Embase and Web of Science, published between December 1, 2019, and January 30, 2021 was performed. Two authors separately screened the titles and abstracts of the documents and ruled out irrelevant articles. A report of the papers that met inclusion criteria was performed; then, a descriptive analysis of the characteristics of the included articles and a narrative synthesis of the results were performed. Results: The review process ended with the inclusion of 145 articles. Most of them were based on single-centre experiences, which spontaneously developed best practices. Most studies were conducted in high-income countries (69.7%) and a part of them (9.6%) were not in English. Prevalence of COVID-19 among dialysis patients accounted for 0%-37.6%. Preventive measures were reported in 54% of the included articles, with particular emphasis on education, triage, hygiene, and containment measures. Patients experienced a heterogeneous spectrum of symptoms that led 35%-88.2% of them&nbsp;to hospital admission. Median and mean hospital length of stay ranged from&nbsp;8&nbsp;to&nbsp;28.5 and 16.2&nbsp;to&nbsp;22&nbsp;days, respectively. Admission to intensive care units varied widely across studies (from 2.6% to 70.5%) and was associated with&nbsp;high mortality (42.8%–100%). Overall, prognosis&nbsp;was poor in 0%–47% of the hospitalized patients. Conclusions: This systematic scoping review provides an overview of the current knowledge on the impact of COVID-19 on the frail world of HD patients. Furthermore, it may help to implement the existing strategies of COVID-19 prevention and provide a list of unmet needs (safe transport, testing, shelter). Finally, it may be a stimulus for performing systematic reviews and meta-analyses which will form the basis for evidence-based guidelines. Graphic abstract: [Figure not available: see fulltext.

Data set and machine learning models for the classification of network traffic originators

The widespread adoption of encryption in computer network traffic is increasing the difficulty of analyzing such traffic for security purposes. The data set presented in this data article is composed of network statistics computed on captures of TCP flows, originated by executing various network stress and web crawling tools, along with statistics of benign web browsing traffic. Furthermore, this data article describes a set of Machine Learning models, trained using the described data set, which can classify network traffic by the tool category (network stress tool, web crawler, web browser), the specific tool (e.g., Firefox), and also the tool version (e.g., Firefox 68) used to generate it. These models are compatible with the analysis of traffic with encrypted payload since statistics are evaluated only on the TCP headers of the packets. The data presented in this article can be useful to train and assess the performance of new Machine Learning models for tool classification