Generic quantum Markov semigroups: the Fock case

We introduce the class of generic quantum Markov semigroups. Within this class we study the class corresponding to the Fock case which is further split into four sub-classes each of which contains both bounded and unbounded generators, depending on some global characteristics of the intensities of jumps. For the first two of these classes we find an explicit solution which reduces the problem of finding the quantum semigroup to the calculation of two classical semigroups, one of which is diagonal (in suitable basis) and the other one is triangular (in the same basis). In the bounded case our formula gives the unique solution. In the unbounded case it gives one solution, which we conjecture to be the minimal one

Generic q-Markov semigroups and speed of convergence of q-algorithms

We study a special class of generic quantum Markov semigroups, on the algebra of all bounded operators on a Hubert space HS, arising in the stochastic limit of a generic system interacting with a boson Fock reservoir. This class depends on an orthonormal basis of HS. We obtain a new estimate for the trace distance of a state from a pure state and use this estimate to prove that, under the action of a semigroup of this class, states with finite support with respect to the given basis converge to equilibrium with a speed which is exponential, but with a polynomial correction which makes the convergence increasingly worse as the dimension of the support increases (Theorem 5.1). We interpret the semigroup as an algorithm, its initial state as input and, following Belavkin and Ohya,10 the dimension of the support of a state as a measure of complexity of the input. With this interpretation, the above results mean that the complexity of the input "slows down" the convergence of the algorithm. Even if the convergence is exponential and the slow down the polynomial, the constants involved may be such that the convergence times become unacceptable from a computational standpoint. This suggests that, in the absence of estimates of the constants involved, distinctions such as "exponentially fast" and "polynomially slow" may become meaningless from a constructive point of view. We also show that, for arbitray states, the speed of convergence to equilibrium is controlled by the rate of decoherence and the rate of purification (i.e. of concentration of the probability on a single pure state). We construct examples showing that the order of magnitude of these two decays can be quite differen

Evolution of endogenous enzyme activities and virgin olive oil characteristics during Chétoui and Chemlali olive ripening

The composition and biochemical characteristics of olive fruits, mainly olive enzymes system, are crucial in determining the final quality of virgin olive oil (VOO). Thus, olives endogenous olive enzyme activities were studied during Chétoui and Chemlali olive ripening. The compositional quality of the corresponding VOO was also studied. Peroxidase (POX) and β-glucosidase activities increased during olives ripening. However, polyphenoloxidase activity decreased slowly. Moreover,the POX enzyme appears to play an essential role in determining VOO total phenol amounts, as the decrease in phenol content registered during olive ripening coincided with the increase in POX activity. A positive correlation between oil antioxidant activity and the total phenol content was established for both the olive cultivars studied. With regard to pigments, chlorophyll content wasmuch higher than that of carotenoids in both Chétoui and Chemlali oils. Moreover, different trends in chlorophyll and carotenoid contents were observed, depending on the olive cultivar. Concerning volatile compounds, our results showed that the highest content of total C6, C5 LOX compounds and pentene dimers was observed at a RI of approximately 3 for both cultivars. However, C6 alcohols and total C5 compounds decreased in Chétoui and Chemlali oils, respectively, during olive ripening

Lupus érythémateux systémique à début pédiatrique: à propos d’un cas

Le lupus érythémateux systémique (LES) est une maladie systémique auto-immune d'étiologie inconnue qui touche essentiellement les femmes àl'âge adulte. Le lupus pédiatrique est une entité rare. Nous rapportons une nouvelle observation. Il s'agissait d'un nourrisson âgé de 7 mois quiprésentait des lésions cutanées purpuriques, une polyarthrite fébrile. Le bilan immunologique était positif (AAN et anti-ADN). Une améliorationclinique et biologique a été notée sous corticothérapie générale avec une récidive lors de la dégression du traitement

Kyste hydatique cervico mediastinal a propos d’un cas

Le kyste hydatique cervico-médiastinal est extrêmement rare même en pays d’endémie. Il se manifeste généralement par une masse cervico-thoracique et il pose un problème délicat de diagnostic. Les auteurs rapportent le cas d’une femme de 53 ans, qui a consulté pour une masse sus claviculaire gauche évoluant depuis une année. Le bilan radiologique avait conclu au début à un magma d’adénopathies cervico-médiastinales. La patiente a bénéficié, alors, d’une cervicotomie exploratrice avec la découverte en per-opératoire d’un kyste hydatique cervico- médiastinal.Mots clé : Kyste hydatique, localisation cervico-médiastinale, imagerie

Les traumatismes externes du larynx

Objective : Laryngeal injuries are rare. They can be isolated or associated with fractures of the facial skeleton. Early diagnosisand proper initial management may sometimes be difficult or delayed.The indication for surgery depends on the extent of the injury.Materials and methods : We report a retrospective review including thirty patients with laryngeal trauma treated over a 25-year periodResults : The mean age was 30 years. Commonest cause of injury was cut throat injuries followed by road traffic accidents. Fibreoptic endoscopy was performed for all the patients. Ct scan was done for 16 patients. All the patients were classified selon la classification de Schaeffer.More then the half (54%) was classified in stage I and II. Surgery was indicated for 16 patients. The treatment was conservative for all the cases. The middle recurrence was 2 years. Three of our patients developped a sous glottic stenosis. Two of them had a laryngoplasty type Rethi.Conclusion : Their symptoms are variable ranging from obvious airway obstruction to minor or almost missing symptoms. A coordinated team approach is necessary for proper management of these injuries.Keywords : Fibreoptic endoscopy, cervical CT-Scan, laryngeal stenosis, voice therapy session

L\'amylose Laryngée À Propos D\'un Cas

L\'amylose localisée est caractérisée par un dépôt de protéines fibrillaires dans un site de l\'organisme sans atteinte systémique. La localisation laryngée est très rare. Ce diagnostic doit être évoqué devant toute lésion d\'allure bénigne du larynx. Les auteurs rapportent un cas d\'amylose laryngée colligé sur une période de 10 ans.Localized amyloidosis is characterized by the deposition of amyloid fibres in a particular site or organ system in the absence of systemic involvement. The laryngeal location of amylosis is rare. The diagnosis must be suspected in front of any tumor of benign speed of the larynx. Authors report a case of laryngeal amyloidosis brought during a period of 10 years. Journal Tunisien d\'ORL et de chirurgie cervico-faciale Vol. 16 2006: pp. 30-3

Lagranulomatose De Wegener Apropos De Trois Localisations Orl Rares

La granulomatose de Wegener (GW) est une vascularite nécrosante granulomateuse présentant un tropisme particulier pour les voies aériennes supérieures. Nous rapportons 3 cas de la GW correspondants à des localisations ORL rares de la maladie : orbito-meningée, laryngée et linguale. Le but de nos études est d\'analyser les particularités épidemiologiques et cliniques de cette pathologie.Wegener\'s Granulomatosis (WG) is a necrotizing granulomatous vasculitis that has a strong affinity for the upper respiratory tract. We report 3cases of rare ORL locations of Wegener\'s Granulomatosis (orbit, larynx and tongue). The aim of our study is to analyse the characteristic features of WG. Journal Tunisien d\'ORL et de chirurgie cervico-faciale Vol. 16 2006: pp. 26-2