Search results for " bifurcation"
showing 8 items of 68 documents
Electronic implementation of a non-linear oscillator subjected to noise : application to the modeling of neuronal information coding
2011
We study the nonlinear FitzHugh-Nagumo model witch describes the dynamics of excitable neural element. It is well known that this system exhibits three different possible responses. Indeed, the system can be mono-stable, oscillatory or bistable. In the oscillatory regime, the system periodically responds by generating action potential. By contrast, in the mono-stable state the system response remains constant after a transient. Under certain conditions, the system can undergo a bifurcation between the stable and the oscillatory regime via the so called Andronov-Hopf bifurcation. In this Phd thesis, we consider the FitzHugh-Nagumo model in the stable state, that is set near the Andronov-Hopf…
Coronary bifurcations - anatomy, physiology and treatment with selected aspects of left main stem bifurcation
2021
Bifurkacja wieńcowa jest miejscem szczególnym w obrębie krążenia wieńcowego. Charakterystyczna anatomia oraz cechy przepływu krwi w złożony sposób wiążą się z rozmieszczeniem blaszek miażdżycowych. Wybór strategii leczenia zmian bifurkacji wieńcowych wymaga szczególnej uwagi, gdyż wszelkie powikłania w tym rejonie narażają na niedokrwienie istotnie większy obszar miokardium niż w przypadku pojedynczego naczynia. Niniejsza publikacja stanowi przegląd podstawowych informacji o anatomii, klasyfikacji oraz kolejnych krokach aktualnie zalecanych technik leczenia przezskórnego zmian bifurkacji wieńcowych, poczynając od kwalifikacji, przygotowania, poprzez wybór stentu, po optymalizację efektu zab…
Classification of coronary artery bifurcation lesions and treatments: time for a consensus
2008
Background: Percutaneous coronary intervention (PCI) of coronary bifurcation lesions remains a subject of debate. Many studies have been published in this setting. They are often small scale and display methodological flaws and other shortcomings such as inaccurate designation of lesions, heterogeneity, and inadequate description of techniques implemented. Methods: The aim is to propose a consensus established by the European Bifurcation Club (EBC), on the definition and classification of bifurcation lesions and treatments implemented with the purpose of allowing comparisons between techniques in various anatomical and clinical settings. Results: A bifurcation lesion is a coronary artery na…
Die retraktile Mesenteritis*: Diagnostische und therapeutische Aspekte
2008
An 18-year-old boy, who had severe abdominal pain for 18 months associated with marked weight loss, was found to have a stenosed ileal sling on double-contrast radiology of the small intestine. At operation a plate-like tumour was extending from the pancreas to the aortic bifurcation. Histological examination of removed tissue revealed retractile mesenteritis (mesenteric panniculitis; liposclerotic mesenteritis). The symptoms regressed and the patient again gained weight under immunotherapy with 1 mg/kg of prednisone and 2 mg/kg of cyclophosphamide daily. Subsequently, under prednisone alone, there was a recurrence, which responded within five weeks to daily 60 mg prednisone and 125 mg cycl…
TCT-437 Clinical outcome of coronary bifurcation management with a “fully bioresorbable” technique. Results of the multicentre BBS study
2016
Gluteal Compartment Syndrome Following Abdominal Aortic Aneurysm Treatment: Case Report and Review of the Literature
2016
Compartment syndrome (CS) is a pathological increase of the interstitial pressure within the closed osseous fascial compartments. Trauma is the most common cause, followed by embolization, burns, and iatrogenic injuries; it usually involves the limbs. The major issue when dealing with CS is the possibility to do an early diagnosis in order to intervene precociously, through a fasciotomy, reducing the risk of tissue, vascular and nervous damage. Although it is an infrequent condition, it is potentially life threatening. In our case report, we present a 59-year-old patient, smoker, affected by hypertension, dyslipidemia, chronic renal failure, and morbid obesity who came at our attention for …
Pinning of a kink in a nonlinear diffusive medium with a geometrical bifurcation: Theory and experiments
2004
International audience; We study the dynamics of a kink propagating in a Nagumo chain presenting a geometrical bifurcation. In the case of weak couplings, we define analytically and numerically the coupling conditions leading to the pinning of the kink at the bifurcation site. Moreover, real experiments using a nonlinear electrical lattice confirm the theoretical and numerical predictions.
Positive solutions for nonlinear Robin problems
2017
We consider a parametric Robin problem driven by the p-Laplacian with an indefinite potential and with a superlinear reaction term which does not satisfy the Ambrosetti-Rabinowitz condition. We look for positive solutions. We prove a bifurcation-type theorem describing the nonexistence, existence and multiplicity of positive solutions as the parameter varies. We also show the existence of a minimal positive solution $\tilde{u}_\lambda$ and establish the monotonicity and continuity of the map $\lambda\to \tilde{u}_\lambda$.