On the Influence of the Data Sampling Interval on Computer-Derived K-Indices

The K index was devised by Bartels et al. (1939) to provide an objective monitoring of irregular geomagnetic activity. The K index was then routinely used to monitor the magnetic activity at permanent magnetic observatories as well as at temporary stations. The increasing number of digital and sometimes unmanned observatories and the creation of INTERMAGNET put the question of computer production of K at the centre of the debate. Four algorithms were selected during the Vienna meeting (1991) and endorsed by IAGA for the computer production of K indices. We used one of them (FMI algorithm) to investigate the impact of the geomagnetic data sampling interval on computer produced K values through the comparison of the computer derived K values for the period 2009, January 1st to 2010, May 31st at the Port-aux-Francais magnetic observatory using magnetic data series with different sampling rates (the smaller: 1 second; the larger: 1 minute). The impact is investigated on both 3-hour range values and K indices data series, as a function of the activity level for low and moderate geomagnetic activity

ABC likelihood-freee methods for model choice in Gibbs random fields

Gibbs random fields (GRF) are polymorphous statistical models that can be used to analyse different types of dependence, in particular for spatially correlated data. However, when those models are faced with the challenge of selecting a dependence structure from many, the use of standard model choice methods is hampered by the unavailability of the normalising constant in the Gibbs likelihood. In particular, from a Bayesian perspective, the computation of the posterior probabilities of the models under competition requires special likelihood-free simulation techniques like the Approximate Bayesian Computation (ABC) algorithm that is intensively used in population genetics. We show in this paper how to implement an ABC algorithm geared towards model choice in the general setting of Gibbs random fields, demonstrating in particular that there exists a sufficient statistic across models. The accuracy of the approximation to the posterior probabilities can be further improved by importance sampling on the distribution of the models. The practical aspects of the method are detailed through two applications, the test of an iid Bernoulli model versus a first-order Markov chain, and the choice of a folding structure for two proteins.Comment: 19 pages, 5 figures, to appear in Bayesian Analysi

Endométriose : pourquoi se développe-telle ?

peer reviewedL’endométriose est une maladie œstrogéno-dépendante responsable d’une morbidité importante liée notamment aux opérations multiples et aux phénomènes douloureux. De nouvelles données sur les facteurs génétiques, le rôle possible de l’environnement, du système immunitaire, de l’inflammation offrent des nouvelles perspectives concernant la physiopathogénie de cette affection permettant ainsi de nouvelles approches thérapeutiques et d’autres voies pour un diagnostic moins invasif que la cœlioscopie exploratrice.Endometriosis is an estrogen-dependent disorder that can result in substantial morbidity, including multiple operations, and pelvic pain. New findings on the genetics, the possible roles of the environment, the immune system, and the inflammation have given insight into the pathogenesis of this disorder and serve as the background for new treatments and new diagnostic approach

Reduction of apoptosis and proliferation in endometriosis

Objective: To evaluate whether endometriosis could be related to an impaired balance between apoptosis and proliferation, two processes which could be modulated by hormonal status. Design: Immunohistochemical study. Setting: Academic research laboratory. Intervention(s): Endometriotic samples obtained from peritoneum of women aged 26-40 years who were undergoing laparoscopy for pain or infertility. Main Outcome Measure(s): Apoptotic cells were detected with the use of the terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) assay. The production of p53 and bcl-2, estrogen and Progesterone (P) receptors, and cellular proliferation were assessed by immunohistochemistry in eutopic and ectopic endometria from 30 patients with endometriosis throughout the menstrual cycle. Results were compared with those from normal endometria from 15 fertile patients. Result(s): Endometriotic lesions were characterized by reduced TUNEL and p53 stainings and by enhanced bcl-2 staining. No correlation between apoptosis and estrogen receptor or P receptor levels was found. A lower amount of steroid receptor was found in endometriotic tissues, without cyclic modulation, compared with the eutopic endometrium. Conclusion(s): Our results suggest that when endometrial tissue is located at ectopic locations, it differs from eutopic endometrium by its proliferation rate, steroid hormone levels, and markers of apoptosis. A reduced sensitivity of endometriotic cells to apoptosis could promote the dissemination and implantation of these cells to ectopic sites. (C) 2004 by American Society for Reproductive Medicine.Peer reviewe

Redução de estoque de componentes eletrônicos de empresa de automação comercial

Orientador : Roberto CerviArtigo (especialização) - Universidade Federal do Paraná, Setor de Ciências Sociais Aplicadas. Curso de Especialização MBA em Gestão da QualidadeInclui referênciasResumo : A finalidade deste artigo é expor o case de uma empresa do segmento de tecnologia, a qual possui dentro de seus estoques uma fração de materiais que não giram há mais de 360 dias, apresentando um cenário que visa a redução do valor de estoque da organização através de ferramentas de gestão para a diminuição da quantidade de itens armazenados. Para uma melhor análise e entendimento são expostos gráficos sobre os itens que não giram, aonde são utilizados, os valores envolvidos e também a razão dos estoques não terem girado conforme o previsto. De posse dessas informações, bem como de algumas referências bibliográficas sobre o tema, cenários são levantados de modo a gerar linhas de ação para tomadas de decisão, todas no sentido de reduzir o valor dos estoques sem giro e que impactam diretamente no resultado financeiro da empresa objeto deste estudo de caso

An Eulerian finite volume solver for multi-material fluid flows with cylindrical symmetry.

International audienceIn this paper, we adapt a pre-existing 2D cartesian cell centered finite volume solver to treat the compressible 3D Euler equations with cylindrical symmetry. We then extend it to multi-material flows. Assuming cylindrical symmetry with respect to the z axis (i.e. all the functions do not depend explicitly on the angular variable $\theta$), we obtain a set of five conservation laws with source terms that can be decoupled in two systems solved on a 2D orthogonal mesh in which a cell as a torus geometry. A specific upwinding treatment of the source term is required and implemented for the stationary case. Test cases will be presented for vanishing and non-vanishing azimuthal velocity $u_{\theta}$

Formation & Dissociation of Methane Hydrates in Sediments. Part II : Numerical modelling

5 pagesThe ForDiMHyS project is a program devoted to experimental studies and the model development of the kinetics of FORmation and Dissociation of Methane Hydrates in Sediments. The first part of the project which is presented in another paper (Bonnefoy and Herri, 2002) is designed to obtain experimental data on hydrate formation & dissociation under in-situ temperature and pressure conditions of methane hydrate in well constrained porous materials. The second part presented hereafter consists in modelling the flows inside the core; a specific numerical model has been developed to simulate the experimental set-up described in part one. The numerical model is 3D three phases and simulates the kinetics of hydrate dissociation and formation, taking into account the solubility of methane in water and the heat of phase transitions

Adhesion of endometrial cells labeled with 111 Indium-tropolonate to peritoneum: a novel in vitro model to study endometriosis

Objective: To evaluate, in a new original in vitro assay, putative factors that could modulate the adhesion of endometrial cells to peritoneum. Design: Prospective, controlled in vitro study. Setting: Academic research laboratory. Patient(s): Fourteen nonmenopausal women undergoing hysterectomy or laparoscopy for benign gynecologic indication. Intervention(s): Endometrial cells obtained from women with regular cycles without endometriosis were labeled with (111)Indium and confronted in vitro with mouse peritoneum in the presence of various cytokines and/or antiadhesive compounds. Main Outcome Measure(s): Radioactivity in (111)Indium-labeled endometrial cells. Result(s): The adhesion of human endometrial cells to mouse peritoneum was increased by treatment with pro-inflammatory cytokines (interleukin IL-1 beta, IL-6, TNF alpha, TGF-beta1). Whereas heparan sulfate had no effect on cell adhesion, a gel of ferric hyaluronate (Intergel) was able to counteract the pro-adhesive effect of cytokines. Interestingly, the pretreatment of peritoneum with cytokines, 24 hours before cell seeding in the presence of the ferric hyaluronate gel, restored the cytokine-promoting effect on cell adhesion. Conclusion(s): Proinflammatory cytokines promote the in vitro peritoneal adhesion of endometrial cells. An antiadhesive hyaluronate gel used in clinics decreases the adhesion in a dose-dependent manner and reduces cytokine bioavailability. (Fertil Steril((R)) 2003;79(Suppl 1):724-9. (C) 2003 by American Society for Reproductive Medicine.).Peer reviewe

Pancreatic head cancer in patients with chronic pancreatitis

International audienceBACKGROUND: Chronic pancreatitis (CP) is a risk factor of pancreatic adenocarcinoma (PA). The discovery of a pancreatic head lesion in CP frequently leads to a pancreaticoduodenectomy (PD) which preceded by a multidisciplinary meeting (MM). The aim of this study was to evaluate the relevance between this indication of PD and the definitive pathological results. METHODS: Between 2000 and 2010, all patients with CP who underwent PD for suspicion of PA without any histological proof were retrospectively analyzed. The operative decision has always been made at an MM. The definitive pathological finding was retrospectively confronted with the decision made at an MM, and patients were classified in two groups according to this concordance (group 1) or not (group 2). Clinical and biological parameters were analyzed, preoperative imaging were reread, and confronted to pathological findings in order to identify predictive factors of malignant degeneration. RESULTS: During the study period, five of 18 (group 1) patients with CP had PD were histologically confirmed to have PA, and the other 13 (group 2) did not have PA. The median age was 52.5+/-8.2 years (gender ratio 3.5). The main symptoms were pain (94.4%) and weight loss (72.2%). There was no patient's death. Six (33.3%) patients had a major complication (Clavien-Dindo classification ≥ 3). There was no statistical difference in clinical and biological parameters between the two groups. The rereading of imaging data could not detect efficiently all patients with PA. CONCLUSIONS: Our results confirmed the difficulty in detecting malignant transformation in patients with CP before surgery and therefore an elevated rate of unnecessary PD was found. A uniform imaging protocol is necessary to avoid PD as a less invasive treatment could be proposed