Cardiovascular changes induced by cold water immersion during hyperbaric hyperoxic exposure.

The present study was designed to assess the cardiac changes induced by cold water immersion compared with dry conditions during a prolonged hyperbaric and hyperoxic exposure (ambient pressure between 1.6 and 3 ATA and PiO(2) between 1.2 and 2.8 ATA). Ten healthy volunteers were studied during a 6 h compression in a hyperbaric chamber with immersion up to the neck in cold water while wearing wet suits. Results were compared with measurements obtained in dry conditions. Echocardiography and Doppler examinations were performed after 15 min and 5 h. Stroke volume, left atrial and left ventricular (LV) diameters remained unchanged during immersion, whereas they significantly fell during the dry session. As an index of LV contractility, percentage fractional shortening remained unchanged, in contrast to a decrease during dry experiment. Heart rate (HR) significantly decreased after 5 h, although it had not changed during the dry session. The changes in the total arterial compliance were similar during the immersed and dry sessions, with a significant decrease after 5 h. In immersed and dry conditions, cardiac output was unchanged after 15 min but decreased by almost 20% after 5 h. This decrease was related to a decrease in HR during immersion and to a decrease in stroke volume in dry conditions. The hydrostatic pressure exerted by water immersion on the systemic vessels could explain these differences. Indeed, the redistribution of blood volume towards the compliant thoracic bed may conceal a part of hypovolaemia that developed in the course of the session

Assessment of the double integration method using accelerometers data for conventional railway platforms

The main goal of this paper is to show a valid method to filter and double-integrate acceleration data from piezo-electric accelerometer installed in conventional railway platforms. The experimentation site involved is located in the region of Lille (north of France). Prospection tests were carried out at this site, including boreholes till 10 m depth and Panda tests (dynamic cone resistance) till 1.2 m depth. Accelerometers were installed in the interlayer of the platform. Acceleration data were recorded during the circulation of different types of train. Theses acceleration signals were then double-integrated in order to obtain the velocity and displacements within this layer. Different filters were applied to obtain relevant displacement results. Comparison was made regarding different axial weights corresponding to Intercity, Freight and TGV trains.SNC

A 60-million-year Cenozoic history of western Amazonian ecosystems in Contamana, eastern Peru

Weprovide a synopsis of ~60million years of life history in Neotropical lowlands, based on a comprehensive survey of the Cenozoic deposits along the Quebrada Cachiyacu near Contamana in PeruvianAmazonia. The 34 fossilbearing localities identified have yielded a diversity of fossil remains, including vertebrates,mollusks, arthropods, plant fossils, and microorganisms, ranging from the early Paleocene to the lateMiocene–?Pliocene (N20 successive levels). This Cenozoic series includes the base of the Huchpayacu Formation (Fm.; early Paleocene; lacustrine/ fluvial environments; charophyte-dominated assemblage), the Pozo Fm. (middle + ?late Eocene; marine then freshwater environments; most diversified biomes), and complete sections for the Chambira Fm. (late Oligocene–late early Miocene; freshwater environments; vertebrate-dominated faunas), the Pebas Fm. (late early to early late Miocene; freshwater environments with an increasing marine influence; excellent fossil record), and Ipururo Fm. (late Miocene–?Pliocene; fully fluvial environments; virtually no fossils preserved). At least 485 fossil species are recognized in the Contamana area (~250 ‘plants’, ~212 animals, and 23 foraminifera). Based on taxonomic lists from each stratigraphic interval, high-level taxonomic diversity remained fairly constant throughout themiddle Eocene–Miocene interval (8-12 classes), ordinal diversity fluctuated to a greater degree, and family/species diversity generally declined, with a drastic drop in the early Miocene. The Paleocene–?Pliocene fossil assemblages from Contamana attest at least to four biogeographic histories inherited from (i) Mesozoic Gondwanan times, (ii) the Panamerican realm prior to (iii) the time of South America’s Cenozoic “splendid isolation”, and (iv) Neotropical ecosystems in the Americas. No direct evidence of any North American terrestrial immigrant has yet been recognized in the Miocene record at Contamana.Facultad de Ciencias Naturales y Muse

10 years of CEMARA database in the AnDDI-Rares network: a unique resource facilitating research and epidemiology in developmental disorders in France

Background : In France, the Ministry of Health has implemented a comprehensive program for rare diseases (RD) that includes an epidemiological program as well as the establishment of expert centers for the clinical care of patients with RD. Since 2007, most of these centers have entered the data for patients with developmental disorders into the CEMARA population-based registry, a national online data repository for all rare diseases. Through the CEMARA web portal, descriptive demographic data, clinical data, and the chronology of medical follow-up can be obtained for each center. We address the interest and ongoing challenges of this national data collection system 10 years after its implementation. Methods : Since 2007, clinicians and researchers have reported the “minimum dataset (MDS)” for each patient presenting to their expert center. We retrospectively analyzed administrative data, demographic data, care organization and diagnoses. Results : Over 10 years, 228,243 RD patients (including healthy carriers and family members for whom experts denied any suspicion of RD) have visited an expert center. Among them, 167,361 were patients affected by a RD (median age 11 years, 54% children, 46% adults, with a balanced sex ratio), and 60,882 were unaffected relatives (median age 37 years). The majority of patients (87%) were seen no more than once a year, and 52% of visits were for a diagnostic procedure. Among the 2,869 recorded rare disorders, 1,907 (66.5%) were recorded in less than 10 patients, 802 (28%) in 10 to 100 patients, 149 (5.2%) in 100 to 1,000 patients, and 11 (0.4%) in > 1,000 patients. Overall, 45.6% of individuals had no diagnosis and 6.7% had an uncertain diagnosis. Children were mainly referred by their pediatrician (46%; n = 55,755 among the 121,136 total children referrals) and adults by a medical specialist (34%; n = 14,053 among the 41,564 total adult referrals). Given the geographical coverage of the centers, the median distance from the patient’s home was 25.1 km (IQR = 6.3 km-64.2 km). Conclusions : CEMARA provides unprecedented support for epidemiological, clinical and therapeutic studies in the field of RD. Researchers can benefit from the national scope of CEMARA data, but also focus on specific diseases or patient subgroups. While this endeavor has been a major collective effort among French RD experts to gather large-scale data into a single database, it provides tremendous potential to improve patient care

Modélisation du comportement des argiles saturées en température (Application aux ouvrages de stockage de déchets radiactifs)

Dans le cadre du concept Multi-barrières pour le stockage géologique de déchets radioactifs de haute activité, on étudie l impact de la sollicitation thermique, due aux colis, sur l évolution irréversible du comportement THM de l argile de la barrière ouvragée. A l issue d une synthèse des résultats expérimentaux publiés dans la littérature concernant les effets du chauffage sur le comportement de l argile, on propose un modèle élastoplastique de Cam Clay, étendu en température et couplé à une variable d endommagement, afin de mieux décrire le comportement de l argile en température sur l ensemble de la gamme de consolidation du matériau, de normalement consolidé à fortement surconsolidé. Finalement, on réalise des essais de chauffage sur des argiles normalement consolidées pour une meilleure identification du comportement en température des argiles.Within the framework of deep geological repository for nuclear waste, we study the thermal effect induced by high-level radioactive waste, on the behavior of the engineered clay barrier. After a synthesis of the published experimental results concerning the effects of heating on the behavior of the clay, we propose an elastoplastic model, of Cam Clay type, extended to temperature and coupled to the damage with a variable of damage. Thus we can better describe the behavior of the clay in temperature, on the whole pallet of states of the clay, from normally consolidated to strongly overconsolidated. Finally, we realize heating test on normally consolidated clays for a better identification of the behavior of clays in temperature.RENNES-INSA (352382210) / SudocSudocFranceF

Pellets d'argiles gonflantes (élaboration et caractérisation hydromécanique)

Le principal atout des pellets est de constituer un matériau avec une mise en place aisée. Néanmoins, la porosité des structures est alors plus importante et les pressions de gonflement sont plus faibles. Sachant qu'à grande profondeur les pressions hydrauliques peuvent atteindre plusieurs mpa, le 1er objectif de l'étude a été de montrer que de telles pressions n'altèrent pas la pression de gonflement. Une étude bibliographique, couplée à des essais d'injection ont permis de montrer que les pressions hydrauliques ne sont pas un facteur limitant l'utilisation des pellets. Toutes les méthodes de fabrication des pellets ont données des dimensions de pellets de 20 mm et une densité sèche supérieure a 1,9 g/cm 3. Néanmoins, des essais d'imbibition ont montre qu'utilisées seules la porosité interpellet etait trop importante pour obtenir une pression de gonflement. Deux approches ont alors été adoptées pour diminuer la porosité : (i) mélange discrets de pellets et (ii) mélange de pellets et de poudre. Dans le 1er cas, des calculs ont montré qu'il est préférable d'utiliser au moins 3 classes de pellets pour obtenir la porosité souhaitée. Dans le 2ème cas, l'introduction de pellets dans les échantillons apportent une échelle supplémentaire à la structuration des argiles. À densité sèche homogénéisée égale, les mélanges pellets-poudre et les échantillons d'argiles compactées présentent des caractéristiques semblables. Par contre, les phénomènes transitoires sont plus marqués dans les mélanges car les cellules et les pellets sont du même ordre de grandeur. Ainsi, si la taille des pellets devient négligeable devant la taille des cellules, l'effondrement observé pendant l'hydratation des mélanges devraient être plus faible. Ainsi, de tels milieux peuvent être modélisés par des modèles d'homogénéisation. Les 1ères bases d'une telle modélisation ont été posées en étudiant les propriétés hydrodynamiques du milieu considéré indéformable.LILLE1-BU (590092102) / SudocSudocFranceF

The characterisation of metal soaps

To characterize more fully the metal soaps found in paint films or on metal surfaces, several metal soaps were synthesized and their X-ray diffraction pattern and Fourier transform infrared (FTIR) and Raman spectra measured. Metal soaps were obtained from four different fatty acids found in drying oils — two saturated (palmitic and stearic acids) and two unsaturated (oleic and linoleic acids) — and from copper, zinc and lead, three metals that are typically found in metal alloys and paint systems. Data are reported for the following compounds: palmitic acid, stearic acid, oleic acid, linoleic acid, zinc palmitate, zinc stearate, zinc oleate, zinc linoleate, copper palmitate, copper stearate, copper oleate, lead palmitate, lead stearate and lead oleate. Features that are characteristic of specific compounds were observed. Soaps obtained from different fatty acids with the same metal ion show differences, as do soaps obtained with the same fatty acid but with different metal ions. Identification is key to understanding how and why metal soaps form on actual objects, and this may lead to preventive measures