Search results for "Regular"

Optimal Control of the Lotka-Volterra Equations with Applications

2022

In this article, the Lotka-Volterra model is analyzed to reduce the infection of a complex microbiote. The problem is set as an optimal control problem, where controls are associated to antibiotic or probiotic agents, or transplantations and bactericides. Candidates as minimizers are selected using the Maximum Principle and the closed loop optimal solution is discussed. In particular a 2d-model is constructed with 4 parameters to compute the optimal synthesis using homotopies on the parameters.

A singular (p,q)-equation with convection and a locally defined perturbation

2021

We consider a parametric Dirichlet problem driven by the (p,q)-Laplacian and a reaction which is gradient dependent (convection) and the competing effects of two more terms, one a parametric singular term and a locally defined perturbation. We show that for all small values of the parameter the problem has a positive smooth solution.

Regularization of perturbed state-dependent sweeping processes with nonregular sets

2018

International audience; In this paper, we prove the convergence strongly pointwisely (up to a subsequence) of Moreau-Yosida regularization of perturbed state-dependent sweeping process with nonregular (subsmooth and positively alpha-far) sets in separable Hilbert spaces. Some relevant consequences are indicated.

Brief communication: Vehicle routing problem and UAV application in the post-earthquake scenario

2017

Abstract. In this paper we simulate a Unmanned Aerial Vehicle's (UAV) recognition after a possible case of diffuse damage after a seismic event in the town of Acireale (Sicily, Italy). Given a set of sites (84 relevant buildings) and the range of the UAV, we are able to find the number of vehicles to employ and the shortest survey path. The problem of finding the shortest survey path is an operational research problem called Vehicle Routing Problem (VRP) whose solution is known to be computationally time-consuming. We used the Simulated Annealing (SA) heuristic that is able to provide stable solutions in relatively short computing time. We also examined the distribution of the cost of the s…

Singularity formation and separation phenomena in boundary layer theory

2009

In this paper we review some results concerning the behaviour of the incompressible Navier–Stokes solutions in the zero viscosity limit. Most of the emphasis is put on the phenomena occurring in the boundary layer created when the no-slip condition is imposed. Numerical simulations are used to explore the limits of the theory. We also consider the case of 2D vortex layers, i.e. flows with internal layers in the form of a rapid variation, across a curve, of the tangential velocity.

Singularities for Prandtl's equations.

2006

We used a mixed spectral/finite-difference numerical method to investigate the possibility of a finite time blow-up of the solutions of Prandtl's equations for the case of the impulsively started cylinder. Our toll is the complex singularity tracking method. We show that a cubic root singularity seems to develop, in a time that can be made arbitrarily short, from a class of data uniformely bounded in H^1.

Codes and automata

2006

Fiziskās aktivitātes inducēto ekstracelulāro vezikulu ietekme uz priekšdziedzera audzēja attīstību žurkās

2022

Priekšdziedzera vēzis (PV) ir viens no biežāk sastopamajiem ļaundabīgā audzēja veidiem vīriešiem, un, lai uzlabotu terapijas efektivitāti un pacientu dzīves kvalitāti, viens no līdzekļiem varētu būt regulāra fiziska aktivitāte. Ekstracelulārās vezikulas (EV) tiek uzskatītas par vienu no būtiskākajiem starpšūnu komunikācijas veidiem, un vairāki pētījumi ir parādījuši, ka to produkcija tiek inducēta fiziskās aktivitātes laikā. Šajā pētījumā tika noteikta fiziskās slodzes laikā veidojušos EV RNS profila izmaiņas, kā arī šo EV ietekme uz PV attīstību metastātiskā žurku PV modelī. Tika atrasti 20 diferenciāli ekspresēti gēni salīdzinot EV RNS saturu pirms un pēc slodzes, un 52 – salīdzinot aktīv…

Coherence Checking and Propagation of Lower Probability Bounds

2003

In this paper we use imprecise probabilities, based on a concept of generalized coherence (g-coherence), for the management of uncertain knowledge and vague information. We face the problem of reducing the computational difficulties in g-coherence checking and propagation of lower conditional probability bounds. We examine a procedure, based on linear systems with a reduced number of unknowns, for the checking of g-coherence. We propose an iterative algorithm to determine the reduced linear systems. Based on the same ideas, we give an algorithm for the propagation of lower probability bounds. We also give some theoretical results that allow, by suitably modifying our algorithms, the g-coher…

Hypoxia inducible factor-1alpha inactivation unveils a link between tumor cell metabolism and hypoxia-induced cell death.

2008

Hypoxia and the acquisition of a glycolytic phenotype are intrinsic features of the tumor microenvironment. The hypoxia inducible factor-1alpha (HIF-1alpha) pathway is activated under hypoxic conditions and orchestrates a complex transcriptional program that enhances cell survival. Although the consequences of HIF-1alpha inactivation in cancer cells have been widely investigated, only a few studies have addressed the role of HIF-1alpha in the survival of cancer cells endowed with different glycolytic capacities. In this study, we investigated this aspect in ovarian cancer cells. Hypoxia-induced toxicity was increased in highly glycolytic cells compared with poorly glycolytic cells; it was a…