120 research outputs found

    2008, une année d'animations au service des sciences de la Terre en Bretagne.

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    Bilan régional de l'Année Internationale de la Planète TerreVous trouverez dans ce rapport un bilan du "programme CAREN" pour l'Année de la Terre, ou plus exactement de l'Année Internationale de la Planète Terre 2008. Il s'agit d'une année patronnée par l'UNESCO et l'Union Internationale des Sciences Géologiques (IUGS) avec un programme scientifique et des animations de sensibilisation du "grand public" partout dans le monde, avec une idée forte : "Les Géosciences au service de l'humanité" L'effort du programme scientifique a porté sur 10 grands thèmes multidisciplinaires, concernant la société : - la Terre et la santé - construire un environnement sain - le climat - climats anciens, climats futurs - les eaux souterraines - pour un usage durable - l'océan - la Planète Bleue - les sols - l'épiderme de la Terre - la Terre profonde - de la croûte au noyau - les mégapoles - aller plus loin, construire autrement - les risques naturels - minimiser les risques, maximiser la prévention - les ressources - vers un usage durable - la Terre et la vie - origine de la biodiversité (thème co-dirigé par l'Allemagne et la France) La Fédération Française de Géologie (dont Cécile Robin - MC à l'université de Rennes 1 / Géosciences Rennes - est la correspondante en Bretagne) et le CAREN (Centre armoricain de recherches en environnement, et plus particulièrement le laboratoire de Géosciences Rennes), ainsi que le BRGM Bretagne, se sont engagés dans cette manifestation internationale et ont proposé un ensemble d'animations de culture scientifique sur le thème "Représenter et comprendre la Terre" (sous la forme d'expositions, festivals, conférences, excursions, interventions dans les écoles, etc. etc.), qui ont touché au final près de 8000 personnes.Vous trouverez donc dans ce rapport un bilan complet de ce programme d'animations en Bretagne

    Dirac Particles in a Gravitational Field

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    The semiclassical approximation for the Hamiltonian of Dirac particles interacting with an arbitrary gravitational field is investigated. The time dependence of the metrics leads to new contributions to the in-band energy operator in comparison to previous works on the static case. In particular we find a new coupling term between the linear momentum and the spin, as well as couplings which contribute to the breaking of the particle - antiparticle symmetry

    Semiclassical Dynamics of Dirac particles interacting with a Static Gravitational Field

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    The semiclassical limit for Dirac particles interacting with a static gravitational field is investigated. A Foldy-Wouthuysen transformation which diagonalizes at the semiclassical order the Dirac equation for an arbitrary static spacetime metric is realized. In this representation the Hamiltonian provides for a coupling between spin and gravity through the torsion of the gravitational field. In the specific case of a symmetric gravitational field we retrieve the Hamiltonian previously found by other authors. But our formalism provides for another effect, namely, the spin hall effect, which was not predicted before in this context

    Enhance quality care performance: Determination of the variables for establishing a common database in French paediatric critical care units

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    Abstract Selected variables for the French Paediatric Intensive Care registry. Rationale, aims, and objectives Providing quality care requires follow-up in regard to clinical and economic activities. Over the past decade, medical databases and patient registries have expanded considerably, particularly in paediatric critical care medicine (eg, the Paediatric Intensive Care Audit Network (PICANet) in the UK, the Australian and New Zealand Paediatric Intensive Care (ANZPIC) Registry in Australia and New Zealand, and the Virtual Paediatric Intensive Care Unit Performance System (VPS) in the USA). Such a registry is not yet available in France. The aim of this study was to determine variables that ought to be included in a French paediatric critical care registry. Methods Variables, items, and subitems from 3 foreign registries and 2 French local databases were used. Items described each variable, and subitems described items. The Delphi method was used to evaluate and rate 65 variables, 90 items, and 17 subitems taking into account importance or relevance based on input from 28 French physicians affiliated with the French Paediatric Critical Care Group. Two ratings were used between January and May 2013. Results Fifteen files from 10 paediatric intensive care units were included. Out of 65 potential variables, 48 (74%) were considered to be indispensable, 16 (25%) were considered to be optional, and 1 (2%) was considered to be irrelevant. Out of 90 potential items, 62 (69%) were considered to be relevant, 23 (26%) were considered to be of little relevance, and 5 (6%) were considered to be irrelevant. Out of 17 potential subitems, 9 (53%) were considered to be relevant, 6 (35%) were considered to be of little relevance, and 2 (12%) were considered to be irrelevant. Conclusions The necessary variables that ought to be included in a French paediatric critical care registry were identified. The challenge now is to develop the French registry for paediatric intensive care units

    Catalytic ozonation with γ-Al2O3 to enhance the degradation of refractory organics in water

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    Nowadays, heterogeneous catalytic ozonation appears as a promising way to treat industrial wastewaters containing refractory pollutants, which resist to biological treatments. Several oxides and minerals have been used and their behavior is subject to controversy with particularly the role of Lewis acid sites and/or basic sites and the effect of salts. In this study, millimetric mesoporous γ-Al2O3 particles suitable for industrial processes were used for enhancing the ozonation efficiency of petrochemical effluents without pH adjustment. A phenol (2,4-dimethylphenol (2,4-DMP)) was first chosen as petrochemical refractory molecule to evaluate the influence of alumina in ozonation. Single ozonation and ozonation in presence of γ-Al2O3 led to the disappearance of 2,4-DMP in 25 min and a decrease in pH from 4.5 to 2.5. No adsorption of 2,4-DMP occurred on γ-Al2O3. Adding γ-Al2O3 in the process resulted in an increase of the 2,4–DMP oxidation level. Indeed, the total organic carbon (TOC) removal was 14% for a single ozonation and 46% for ozonation with γ-Al2O3. Similarly, chemical oxygen demand (COD) removal increases from 35 to 75%, respectively. Various oxidized by-products were produced during the degradation of 2,4-DMP, but after 5 h ozonation 90% of organic by-products were acetic acid > formic acid ≫ oxalic acid. Some of the carboxylic acids were adsorbed on γ-Al2O3. The use of radical scavengers (tert-butanol) highlighted the involvement of hydroxyl radicals during catalytic ozonation with γ-Al2O3 in contrary to single ozonation, which mainly involved direct ozone reaction. γ-Al2O3 is an amphoteric solid with Lewis acid AlOH(H+) sites and basicAl-OH sites. After ozonation the amount of basic sites decreased due to carboxylates adsorption, while the Lewis acid sites remained constant as evidenced by FTIR. Several ozonation runs with γ-Al2O3 reported a progressive decrease of its catalytic activity due to the cumulative sorption of carboxylates on the basic sites. After 80 h of ozonation, a calcination at 550 °C allowed to recover allAl-OH basic sites and the initial activity of γ-Al2O3. A synthetic petrochemical effluent containing various petrochemicals (phenol, acetic acid, naphtenic acid, pyrene, naphtalene) was then treated with γ-Al2O3 with and without NaCl. Sodium ions prevented carboxylates adsorption on γ-Al2O3 leading to a higher efficiency of γ-Al2O3 in presence of NaCl and allowed to decrease the toxicity of the petrochemical effluent

    Olfactory Receptors in Non-Chemosensory Organs: The Nervous System in Health and Disease

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    Olfactory receptors (ORs) and down-stream functional signaling molecules adenylyl cyclase 3 (AC3), olfactory G protein \u3b1 subunit (G\u3b1olf), OR transporters receptor transporter proteins 1 and 2 (RTP1 and RTP2), receptor expression enhancing protein 1 (REEP1), and UDP-glucuronosyltransferases (UGTs) are expressed in neurons of the human and murine central nervous system (CNS). In vitro studies have shown that these receptors react to external stimuli and therefore are equipped to be functional. However, ORs are not directly related to the detection of odors. Several molecules delivered from the blood, cerebrospinal fluid, neighboring local neurons and glial cells, distant cells through the extracellular space, and the cells' own self-regulating internal homeostasis can be postulated as possible ligands. Moreover, a single neuron outside the olfactory epithelium expresses more than one receptor, and the mechanism of transcriptional regulation may be different in olfactory epithelia and brain neurons. OR gene expression is altered in several neurodegenerative diseases including Parkinson's disease (PD), Alzheimer's disease (AD), progressive supranuclear palsy (PSP) and sporadic Creutzfeldt-Jakob disease (sCJD) subtypes MM1 and VV2 with disease-, region- and subtype-specific patterns. Altered gene expression is also observed in the prefrontal cortex in schizophrenia with a major but not total influence of chlorpromazine treatment. Preliminary parallel observations have also shown the presence of taste receptors (TASRs), mainly of the bitter taste family, in the mammalian brain, whose function is not related to taste. TASRs in brain are also abnormally regulated in neurodegenerative diseases. These seminal observations point to the need for further studies on ORs and TASRs chemoreceptors in the mammalian brain

    The Physics of the B Factories

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    This work is on the Physics of the B Factories. Part A of this book contains a brief description of the SLAC and KEK B Factories as well as their detectors, BaBar and Belle, and data taking related issues. Part B discusses tools and methods used by the experiments in order to obtain results. The results themselves can be found in Part C

    Extracorporeal Membrane Oxygenation for Severe Acute Respiratory Distress Syndrome associated with COVID-19: An Emulated Target Trial Analysis.

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    RATIONALE: Whether COVID patients may benefit from extracorporeal membrane oxygenation (ECMO) compared with conventional invasive mechanical ventilation (IMV) remains unknown. OBJECTIVES: To estimate the effect of ECMO on 90-Day mortality vs IMV only Methods: Among 4,244 critically ill adult patients with COVID-19 included in a multicenter cohort study, we emulated a target trial comparing the treatment strategies of initiating ECMO vs. no ECMO within 7 days of IMV in patients with severe acute respiratory distress syndrome (PaO2/FiO2 <80 or PaCO2 ≥60 mmHg). We controlled for confounding using a multivariable Cox model based on predefined variables. MAIN RESULTS: 1,235 patients met the full eligibility criteria for the emulated trial, among whom 164 patients initiated ECMO. The ECMO strategy had a higher survival probability at Day-7 from the onset of eligibility criteria (87% vs 83%, risk difference: 4%, 95% CI 0;9%) which decreased during follow-up (survival at Day-90: 63% vs 65%, risk difference: -2%, 95% CI -10;5%). However, ECMO was associated with higher survival when performed in high-volume ECMO centers or in regions where a specific ECMO network organization was set up to handle high demand, and when initiated within the first 4 days of MV and in profoundly hypoxemic patients. CONCLUSIONS: In an emulated trial based on a nationwide COVID-19 cohort, we found differential survival over time of an ECMO compared with a no-ECMO strategy. However, ECMO was consistently associated with better outcomes when performed in high-volume centers and in regions with ECMO capacities specifically organized to handle high demand. This article is open access and distributed under the terms of the Creative Commons Attribution Non-Commercial No Derivatives License 4.0 (http://creativecommons.org/licenses/by-nc-nd/4.0/)
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