Some Features of Joint Confidence Regions for the Parameters of the Inverse Weibull Distribution

In this paper, we will study the joint confidence regions for the parameters of inverse Weibull distribution in the point of view of record values. One of the applications of the joint confidence regions of the parameters is to find confidence bounds for the functions of the parameters. Joint confidence regions for the parameters of extreme value distribution are also discussed. In this way we will discus some numerical examples with real data set and simulated data, to illustrate the proposed method. A simulation study is performed to compare the proposed joint confidence regions. Keywords: The joint confidence regions, confidence bounds; inverse Weibull distribution, extreme value distribution

L’hemangiopericytome (a propos de 8 cas)

Description L’hémangiopéricytome est une tumeur rare, mésenchymateuse, qui prend naissance au niveau des péricytes de Zimmerman. Il est souvent confondu avec le méningiome. Objectif Faire le point sur cette entité histologique souvent méconnue. Méthodes Une étude rétrospective de 8 cas d’hémangiopéricytome colligés au Service de Neurochirurgie de l’hôpital Ibn Rochd de Casablanca au Maroc, entre 2000 et 2008. Résultats Il s’agissait de 6 hommes et 2 femmes. L’âge moyen de nos patients était de 50 ans. Le délai moyen de diagnostic était de 4,75 mois. Le tableau clinique était dominé par les signes d’hypertension intracrânienne. Le bilan neuroradiologique a objectivé le caractère unique des lésions, une taille moyenne de 6,33 cm. Tous nos patient ont été traité par chirurgie avec résection subtotale dans 5 cas et totale dans le reste. Un patient a bénéficié de la radiothérapie post opératoire. L’évolution a été marquée par l’apparition d’une récidive, 3 cas de reprise évolutive et un décès. L’apparition de métastases n’a pas été notée dans notre série. Conclusion L’hémangiopéricytome se caractérise par son potentiel malin, son taux élevé de récidive et de métastase à distance. Son évolution est imprévisible nécessitant une surveillance prolongée.Mots clés : Cellules de Zimmerman, Hémangiopéricytome, Méningiom

An Investigation of Inference of the Generalized Extreme Value Distribution Based on Record

In this article, the maximum likelihood and Bayes estimates of the generalized extreme value distribution based on record values are investigated. The asymptotic confidence intervals as well as bootstrap confidence are proposed. The Bayes estimators cannot be obtained in closed form so the MCMC method are used to calculate Bayes estimates as well as the credible intervals. A numerical example is provided to illustrate the proposed estimation methods developed here. Keywords: Generalized extreme value distribution, Record values, Maximum likelihood estimation, Bayesian estimation

Influence of processing conditions on nanoindentation properties of spark plasma sintered ptfe

The Spark Plasma Sintering (SPS) is considered as fast sintering route using self-heating action from inside the powder similar to microwave sintering and self-propagating high temperature. High sintering rate, low temperature processing, ease of operation and accurate control of sintering energy are the major advantages of this non-melting technique with regard to classical methods. The aim of this investigation is to take benefit from the advantages offered by the SPS process in order to sinter the polytetrafluoroethylene (PTFE) polymer materials from PTFE powder particles. The effect of the process’s parameters, namely the sintering temperature and heating rate, on the nanoindentation deformation is explored at room temperature. Empirical data on depth-dependent hardness are confronted to some theoretical models with a special focus on the apparent surface stress changes with the indentation depth. Furthermore, the obtained results are compared to the macro-behavior deduced from tensile and bending properties in order to assess the change in both surface and bulk deformations of the SPSed samples and according to the processing parameters

Une cause inhabituelle d'altération neurologique Postopératoire : La Pneumocéphalie

La pneumocéphalie postopératoire est une complication fréquente chez le traumatisé crânien mais relativement rare de la chirurgie intracrânienne. Nous présentons le cas d’un malade de 8 ans qui, après exérèse d’une volumineuse tumeur de 3ème ventricule, a développé une pneumocéphalie importante révélée par un retard de réveil avec mydriase bilatérale aréactive. A travers cette observation et une revue de la littérature, les caractéristiques cliniques, physiopathologiques et thérapeutiques de cette complication seront discutées

Is diet partly responsible for differences in COVID-19 death rates between and within countries?

Correction: Volume: 10 Issue: 1 Article Number: 44 DOI: 10.1186/s13601-020-00351-w Published: OCT 26 2020Reported COVID-19 deaths in Germany are relatively low as compared to many European countries. Among the several explanations proposed, an early and large testing of the population was put forward. Most current debates on COVID-19 focus on the differences among countries, but little attention has been given to regional differences and diet. The low-death rate European countries (e.g. Austria, Baltic States, Czech Republic, Finland, Norway, Poland, Slovakia) have used different quarantine and/or confinement times and methods and none have performed as many early tests as Germany. Among other factors that may be significant are the dietary habits. It seems that some foods largely used in these countries may reduce angiotensin-converting enzyme activity or are anti-oxidants. Among the many possible areas of research, it might be important to understand diet and angiotensin-converting enzyme-2 (ACE2) levels in populations with different COVID-19 death rates since dietary interventions may be of great benefit.Peer reviewe

Myocardial tagging by Cardiovascular Magnetic Resonance: evolution of techniques--pulse sequences, analysis algorithms, and applications

Cardiovascular magnetic resonance (CMR) tagging has been established as an essential technique for measuring regional myocardial function. It allows quantification of local intramyocardial motion measures, e.g. strain and strain rate. The invention of CMR tagging came in the late eighties, where the technique allowed for the first time for visualizing transmural myocardial movement without having to implant physical markers. This new idea opened the door for a series of developments and improvements that continue up to the present time. Different tagging techniques are currently available that are more extensive, improved, and sophisticated than they were twenty years ago. Each of these techniques has different versions for improved resolution, signal-to-noise ratio (SNR), scan time, anatomical coverage, three-dimensional capability, and image quality. The tagging techniques covered in this article can be broadly divided into two main categories: 1) Basic techniques, which include magnetization saturation, spatial modulation of magnetization (SPAMM), delay alternating with nutations for tailored excitation (DANTE), and complementary SPAMM (CSPAMM); and 2) Advanced techniques, which include harmonic phase (HARP), displacement encoding with stimulated echoes (DENSE), and strain encoding (SENC). Although most of these techniques were developed by separate groups and evolved from different backgrounds, they are in fact closely related to each other, and they can be interpreted from more than one perspective. Some of these techniques even followed parallel paths of developments, as illustrated in the article. As each technique has its own advantages, some efforts have been made to combine different techniques together for improved image quality or composite information acquisition. In this review, different developments in pulse sequences and related image processing techniques are described along with the necessities that led to their invention, which makes this article easy to read and the covered techniques easy to follow. Major studies that applied CMR tagging for studying myocardial mechanics are also summarized. Finally, the current article includes a plethora of ideas and techniques with over 300 references that motivate the reader to think about the future of CMR tagging