133 research outputs found
Multiple solutions for the fractional p-Laplacian with jumping reactions
We study a nonlinear elliptic equation driven by the degenerate
fractional p-Laplacian, with Dirichlet-type condition and a jumping
reaction, i.e., (p − 1)-linear both at infinity and at zero but with different slopes crossing the principal eigenvalue. Under two different sets of hypotheses, entailing different types of asymmetry, we prove the existence of at least two nontrivial solutions. Our method is based on degree theory for monotone operators and nonlinear fractional spectral theory
Five solutions for the fractional p -Laplacian with noncoercive energy
We deal with a Dirichlet problem driven by the degenerate fractional p-Laplacian and involving a nonlinear reaction which satisfies, among other hypotheses, a (p- 1) -linear growth at infinity with non-resonance above the first eigenvalue. The energy functional governing the problem is thus noncoercive. We focus on the behavior of the reaction near the origin, assuming that it has a (p- 1) -sublinear growth at zero, vanishes at three points, and satisfies a reverse Ambrosetti–Rabinowitz condition. Under such assumptions, by means of critical point theory and Morse theory, and using suitably truncated reactions, we show the existence of five nontrivial solutions: two positive, two negative, and one nodal
Laboratorio de Geoquímica Isotópica y Geocronología (SEGECRON): Aspectos Generales de la Metodología U/Pb en Circones con LA-ICP-MS
Fil: González, Liliana. Servicio Geológico Minero Argentino. Instituto de Tecnología Minera; Argentina.Fil: Iannizzotto, Noelia. Servicio Geológico Minero Argentino. Instituto de Geología y Recursos Minerales; Argentina.Fil: Lagorio, Silvia. Servicio Geológico Minero Argentino. Instituto de Geología y Recursos Minerales; Argentina.Fil: López, Faustino A. Servicio Geológico Minero Argentino. Instituto de Tecnología Minera; Argentina.Fil: Pagnanini, Feliciano. Servicio Geológico Minero Argentino. Instituto de Geología y Recursos Minerales; Argentina.Fil: Tedesco, Ana María. Servicio Geológico Minero Argentino. Instituto de Geología y Recursos Minerales; Argentina.La presente contribución tiene por objetivo difundir las nuevas capacidades analíticas del SEGEMAR,
vinculadas a la adquisición de equipamiento y construcción del laboratorio de geoquímica isotópica y
geocronología (SEGECRON). También, constituirá una guía para comprender los conceptos básicos en el funcionamiento del equipamiento y los fundamentos de la técnica, los alcances del método U/Pb en
circones y formar criterios en las acciones de toma de muestras, separación de circones, selección de
especímenes y montaje final para su posterior análisis.
El SEGECRON representa una capacidad hasta ahora inexistente en la República Argentina, consistente en un laboratorio de geoquímica isotópica y geocronológica de alta resolución que permitirá satisfacer
necesidades en las investigaciones geológico-mineras y petroleras, mejorando la calidad de la información y reduciendo los gastos en exploración. Además, asegura la autonomía de Argentina en esta materia, con el fin de generar conocimiento aplicado en los campos de la exploración geológica, minera y petrolera y evaluación de la calidad del recurso hídrico. Contribuirá a la mejora e incremento de la capacidad operativa del SEGEMAR para cumplir, de manera autónoma y competitiva, con la misión asignada como Organismo Científico Tecnológico del Estado Nacional, responsable de la producción de conocimientos e información geológica, tecnológica, minera y ambiental necesaria para promover el desarrollo sostenible de los recursos naturales no renovables y su aprovechamiento racional (Ley 24224). Contribuirá, a partir de la disponibilidad de una nueva capacidad tecnológica en el país, para que otras instituciones y la actividad privada, involucradas directa o indirectamente en los estudios geológico-mineros, dispongan de esta capacidad tecnológica en el país y no dependan de laboratorios del exterior
Guida alla redazione degli atti amministrativi
La "Guida alla redazione degli atti amministrativi" intende fornire indicazioni per la redazione degli atti per tutti i funzionari della pubblica amministrazione. Si articola in tre parti: (a) la lingua degli atti, (b) la struttura del provvedimento amministrativo, (c) il rinvio ad altri atti. Ne è autore un gruppo di linguisti e giuristi facenti capo all'ITTIG-CNR (Istituto per le Tecniche e Tecnologie dell'Informazione Giuridica) e dell'Accademia della Crusca
A neural tracking and motor control approach to improve rehabilitation of upper limb movements
<p>Abstract</p> <p>Background</p> <p>Restoration of upper limb movements in subjects recovering from stroke is an essential keystone in rehabilitative practices. Rehabilitation of arm movements, in fact, is usually a far more difficult one as compared to that of lower extremities. For these reasons, researchers are developing new methods and technologies so that the rehabilitative process could be more accurate, rapid and easily accepted by the patient. This paper introduces the proof of concept for a new non-invasive FES-assisted rehabilitation system for the upper limb, called smartFES (sFES), where the electrical stimulation is controlled by a biologically inspired neural inverse dynamics model, fed by the kinematic information associated with the execution of a planar goal-oriented movement. More specifically, this work details two steps of the proposed system: an <it>ad hoc </it>markerless motion analysis algorithm for the estimation of kinematics, and a neural controller that drives a synthetic arm. The vision of the entire system is to acquire kinematics from the analysis of video sequences during planar arm movements and to use it together with a neural inverse dynamics model able to provide the patient with the electrical stimulation patterns needed to perform the movement with the assisted limb.</p> <p>Methods</p> <p>The markerless motion tracking system aims at localizing and monitoring the arm movement by tracking its silhouette. It uses a specifically designed motion estimation method, that we named Neural Snakes, which predicts the arm contour deformation as a first step for a silhouette extraction algorithm. The starting and ending points of the arm movement feed an Artificial Neural Controller, enclosing the muscular Hill's model, which solves the inverse dynamics to obtain the FES patterns needed to move a simulated arm from the starting point to the desired point. Both position error with respect to the requested arm trajectory and comparison between curvature factors have been calculated in order to determine the accuracy of the system.</p> <p>Results</p> <p>The proposed method has been tested on real data acquired during the execution of planar goal-oriented arm movements. Main results concern the capability of the system to accurately recreate the movement task by providing a synthetic arm model with the stimulation patterns estimated by the inverse dynamics model. In the simulation of movements with a length of ± 20 cm, the model has shown an unbiased angular error, and a mean (absolute) position error of about 1.5 cm, thus confirming the ability of the system to reliably drive the model to the desired targets. Moreover, the curvature factors of the factual human movements and of the reconstructed ones are similar, thus encouraging future developments of the system in terms of reproducibility of the desired movements.</p> <p>Conclusion</p> <p>A novel FES-assisted rehabilitation system for the upper limb is presented and two parts of it have been designed and tested. The system includes a markerless motion estimation algorithm, and a biologically inspired neural controller that drives a biomechanical arm model and provides the stimulation patterns that, in a future development, could be used to drive a smart Functional Electrical Stimulation system (sFES). The system is envisioned to help in the rehabilitation of post stroke hemiparetic patients, by assisting the movement of the paretic upper limb, once trained with a set of movements performed by the therapist or in virtual reality. Future work will include the application and testing of the stimulation patterns in real conditions.</p
Centralised Design and Production of the Ultra-High Vacuum and Laser-Stabilisation Systems for the AION Ultra-Cold Strontium Laboratories
This paper outlines the centralised design and production of the
Ultra-High-Vacuum sidearm and Laser-Stabilisation systems for the AION
Ultra-Cold Strontium Laboratories. Commissioning data on the residual gas and
steady-state pressures in the sidearm chambers, on magnetic field quality, on
laser stabilisation, and on the loading rate for the 3D Magneto-Optical Trap
are presented. Streamlining the design and production of the sidearm and laser
stabilisation systems enabled the AION Collaboration to build and equip in
parallel five state-of-the-art Ultra-Cold Strontium Laboratories within 24
months by leveraging key expertise in the collaboration. This approach could
serve as a model for the development and construction of other cold atom
experiments, such as atomic clock experiments and neutral atom quantum
computing systems, by establishing dedicated design and production units at
national laboratories.Comment: 27 pages, 21 figure
Immunofibroblasts are pivotal drivers of tertiary lymphoid structure formation and local pathology.
Resident fibroblasts at sites of infection, chronic inflammation, or cancer undergo phenotypic and functional changes to support leukocyte migration and, in some cases, aggregation into tertiary lymphoid structures (TLS). The molecular programming that shapes these changes and the functional requirements of this population in TLS development are unclear. Here, we demonstrate that external triggers at mucosal sites are able to induce the progressive differentiation of a population of podoplanin (pdpn)-positive stromal cells into a network of immunofibroblasts that are able to support the earliest phases of TLS establishment. This program of events, that precedes lymphocyte infiltration in the tissue, is mediated by paracrine and autocrine signals mainly regulated by IL13. This initial fibroblast network is expanded and stabilized, once lymphocytes are recruited, by the local production of the cytokines IL22 and lymphotoxin. Interfering with this regulated program of events or depleting the immunofibroblasts in vivo results in abrogation of local pathology, demonstrating the functional role of immunofibroblasts in supporting TLS maintenance in the tissue and suggesting novel therapeutic targets in TLS-associated diseases
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