High-order IMEX-spectral schemes for computing the dynamics of systems of nonlinear Schrödinger /Gross-Pitaevskii equations

International audienceThe aim of this paper is to build and validate some explicit high-order schemes, both in space and time, for simulating the dynamics of systems of nonlinear Schrödinger /Gross-Pitaevskii equations. The method is based on the combination of high-order IMplicit-EXplicit (IMEX) schemes in time and Fourier pseudo-spectral approximations in space. The resulting IMEXSP schemes are highly accurate, efficient and easy to implement. They are also robust when used in conjunction with an adaptive time stepping strategy and appear as an interesting alternative to time-splitting pseudo-spectral (TSSP) schemes. Finally, a complete numerical study is developed to investigate the properties of the IMEXSP schemes, in comparison with TSSP schemes, for one-and two-components systems of Gross-Pitaevskii equations

Acceleration of the imaginary time method for spectrally computing the stationary states of Gross-Pitaevskii equations

International audienceThe aim of this paper is to propose a simple accelerated spectral gradient flow formulation for solving the Gross-Pitaevskii Equation (GPE) when computing the stationary states of Bose-Einstein Condensates. The new algorithm, based on the recent iPiano minimization algorithm [35], converges three to four times faster than the standard implicit gradient scheme. To support the method, we provide a complete numerical study for 1d-2d-3d GPEs, including rotation and dipolar terms

Needs and Perceptions of Patients With Dystonia During the COVID-19 Pandemic: A Qualitative Framework Analysis of Survey Responses From Italy

Introduction:The COVID-19 pandemic and its countermeasures have created changes in both life and healthcare. With the prioritization of COVID-19-related management, the risks and experiences of patients suffering from rare conditions, such as dystonia, during the pandemic remain understudied. Materials and MethodsUsing a framework analysis of a nationwide qualitative online survey, we sought to explore the perspectives of patients with dystonia on their clinical assistance and possible unmet needs during the first pandemic wave. An online survey consisting of 37 items (such as demographic characteristics, dystonia-related features, neurological service provision, therapeutic relationship with the neurologist, perceptions related to virus infection, perceptions about healthcare-related needs, work-related questions, requesting information, and seeking support during the pandemic) was carried out using both close and open-ended questions. ResultsResponses from 62 participants were collected, with most of them from the red zones in Italy, where they were confined indoors. Social isolation was a relevant stressor. Motor and non-motor symptoms increased with detrimental consequences for patients' job and daily functionality. Outpatient clinics and rehabilitation sessions were temporarily shut down, and even telephone/mail support was sparse. Despite efforts, patients felt alone in dealing with dystonia. ConclusionThe first wave of the pandemic and its related restrictions had detrimental consequences for people living with dystonia, and their relevant needs remained unmet. These findings may contribute to implementing remedial healthcare provisions in this pandemic or in future pandemics

Wearable Technologies and AI at the Far Edge for Chronic Heart Failure Prevention and Management: A Systematic Review and Prospects

Smart wearable devices enable personalized at-home healthcare by unobtrusively collecting patient health data and facilitating the development of intelligent platforms to support patient care and management. The accurate analysis of data obtained from wearable devices is crucial for interpreting and contextualizing health data and facilitating the reliable diagnosis and management of critical and chronic diseases. The combination of edge computing and artificial intelligence has provided real-time, time-critical, and privacy-preserving data analysis solutions. However, based on the envisioned service, evaluating the additive value of edge intelligence to the overall architecture is essential before implementation. This article aims to comprehensively analyze the current state of the art on smart health infrastructures implementing wearable and AI technologies at the far edge to support patients with chronic heart failure (CHF). In particular, we highlight the contribution of edge intelligence in supporting the integration of wearable devices into IoT-aware technology infrastructures that provide services for patient diagnosis and management. We also offer an in-depth analysis of open challenges and provide potential solutions to facilitate the integration of wearable devices with edge AI solutions to provide innovative technological infrastructures and interactive services for patients and doctors

Freezing of gait in Parkinson’s disease patients treated with bilateral subthalamic nucleus deep brain stimulation: A long-term overview

Bilateral subthalamic nucleus deep brain stimulation (STN-DBS) is an effective treatment in advanced Parkinson’s Disease (PD). However, the effects of STN-DBS on freezing of gait (FOG) are still debated, particularly in the long-term follow-up (>/=5-years). The main aim of the current study is to evaluate the long-term effects of STN-DBS on FOG. Twenty STN-DBS treated PD patients were included. Each patient was assessed before surgery through a detailed neurological evaluation, including FOG score, and reevaluated in the long-term (median follow-up: 5-years) in different stimulation and drug conditions. In the long term follow-up, FOG score significantly worsened in the off-stimulation/off-medication condition compared with the preoperative off-medication assessment (z = -1.930; p = 0.05) but not in the on-stimulation/off-medication (z = -0.357; p = 0.721). There was also a significant improvement of FOG at long-term assessment by comparing on-stimulation/off-medication and off-stimulation/off-medication conditions (z = -2.944; p = 0.003). These results highlight the possible beneficial long-term effects of STN-DBS on FOG

Freezing of Gait in Parkinson's Disease Patients Treated with Bilateral Subthalamic Nucleus Deep Brain Stimulation: A Long-Term Overview

Bilateral subthalamic nucleus deep brain stimulation (STN-DBS) is an effective treatment in advanced Parkinson's Disease (PD). However, the effects of STN-DBS on freezing of gait (FOG) are still debated, particularly in the long-term follow-up (≥5-years). The main aim of the current study is to evaluate the long-term effects of STN-DBS on FOG. Twenty STN-DBS treated PD patients were included. Each patient was assessed before surgery through a detailed neurological evaluation, including FOG score, and revaluated in the long-term (median follow-up: 5-years) in different stimulation and drug conditions. In the long term follow-up, FOG score significantly worsened in the off-stimulation/off-medication condition compared with the pre-operative off-medication assessment (z = -1.930; p = 0.05) but not in the on-stimulation/off-medication (z = -0.357; p = 0.721). There was also a significant improvement of FOG at long-term assessment by comparing on-stimulation/off-medication and off-stimulation/off-medication conditions (z = -2.944; p = 0.003). These results highlight the possible beneficial long-term effects of STN-DBS on FOG

Physical properties of carbon nanotubes by computational methods

In this thesis, a model for electrons transport properties in metallic Carbon Nanotubes is introduced, including also the effects of the coupling of electrons with optical phonons. The derived equations form a system of bi-dimensional hyperbolic conservation laws with collisionterms on the right hand side. The system is solved by a method of line scheme, with WENO reconstruction and a TVD Runge-Kutta scheme for time integration.L'argomento presentato presentato in uqesta tesi riguarda le proprietà di trasporto degli elettroni in Nanotubi di Carbonio metallici, prendendo in considerazione le interazioni elettrone-fonone. Le equazioni derivate dal modello fisico considerato formano un sistema di Leggi di Conservazione iperboliche bi.dimensionali con termini di collisione a membro destro. Tale sistema è stato risolto tramite il metodo delle linee, con ricostruzione di tipo WENO e scheme di tipo Runge-Kutta di tipo TVD

Il problema della Location

Come primo caso, fruttando il lavoro di Morgan e Bolton, diamo una dimostrazione elementare di una soluzione del problema della location in dimensione 2 che usa semplici risultati di geometria. Successiavamente studiamo il problema nel contesto del trasporto ottimo. Tale contesto è molto più generale e si riesce ad avere una dimostrazione di teoremi di esistenza di soluzioni ottime sia del problema della location che di quello dell'irrigation (relativamente) semplici. In seguito dimostriamo teoremi limite e risultati per il problema asintotico ed infine, dopo un'introduzione alla "quantization", mostreremo alcuni risultati sulla versione probabilistica del problema e faremo vedere che quest'ultima non si discosta molto da quella deterministica

An asymptotic preserving automatic domain decomposition method for the Vlasov-Poisson-BGK system with applications to plasmas

In this work we present an efficient strategy to deal with plasma physics simulations in which localized departures from thermodynamical equilibrium are present. The method is based on the introduction of intermediate regions which allows smooth transitions between kinetic and fluid zones. In this paper we extend Domain Decomposition techniques, obtained through dynamic coupling and buffer zones, to the study of plasmas and, moreover, we combine them with Asymptotic Preserving and Asymptotically Accurate strategies for the time integration. We use a hybrid scheme in which both kinetic and fluid descriptions are considered and coupled together while the kinetic model is solved by asymptotic preserving and accurate methods, in order to guarantee high efficiency and accuracy in all regimes. The numerical scheme is validated and its performances are analyzed by numerical simulations. © 2014 Elsevier Inc