992 resultados para Hyperdynamic circulation
Resumo:
Au coeur même du premier paquet de sept accords bilatéraux conclu entre la Suisse et la Communauté européenne le 21 juin 1999, l'Accord sur la libre circulation des personnes (ALCP) vise à garantir la libre circulation et à faciliter la prestation de services sur le territoire des parties contractantes. Or la réalisation de ces objectifs dépend avant tout de la mise en oeuvre effective de l'interdiction de discrimination en raison de la nationalité consacrée par l'ALCP, véritable clé de voûte de l'Accord. Le présent ouvrage s'attache, dans un premier temps, à l'analyse du principe de libre circulation et à l'examen du fonctionnement de l'ALCP - examen portant notamment sur le rôle joué par la jurisprudence de la Cour de justice des Communautés européennes dans le cadre de l'interprétation de cet Accord (Partie I). Dans un second temps, cet ouvrage se penche sur la question centrale de l'interdiction de discrimination en raison de la nationalité (Partie II). Pour ce faire, il propose tout d'abord une définition de la notion de discrimination elle-même et détermine ensuite le champ d'application matériel et personnel des principales dispositions de l'ALCP interdisant les discriminations. Dans ce cadre, une attention toute particulière est accordée à la question de la potentielle portée horizontale de ces dispositions. Ensuite, l'ouvrage procède à une analyse complète des principes et dispositions susceptibles de limiter la portée de cette interdiction,avant de conclure par un examen détaillé des conséquences administratives et civiles induites par la présence d'un cas de discrimination effectif.
Resumo:
AIM: The prediction of return of spontaneous circulation (ROSC) during resuscitation of patients suffering of cardiac arrest (CA) is particularly challenging. Regional cerebral oxygen saturation (rSO2) monitoring through near-infrared spectrometry is feasible during CA and could provide guidance during resuscitation. METHODS: We conducted a systematic review and meta-analysis on the value of rSO2 in predicting ROSC both after in-hospital (IH) or out-of-hospital (OH) CA. Our search included MEDLINE (PubMed) and EMBASE, from inception until April 4th, 2015. We included studies reporting values of rSO2 at the beginning of and/or during resuscitation, according to the achievement of ROSC. RESULTS: A total of nine studies with 315 patients (119 achieving ROSC, 37.7%) were included in the meta-analysis. The majority of those patients had an OHCA (n=225, 71.5%; IHCA: n=90, 28.5%). There was a significant association between higher values of rSO2 and ROSC, both in the overall calculation (standardized mean difference, SMD -1.03; 95%CI -1.39,-0.67; p<0.001), and in the subgroups analyses (rSO2 at the beginning of resuscitation: SMD -0.79; 95%CI -1.29,-0.30; p=0.002; averaged rSO2 value during resuscitation: SMD -1.28; 95%CI -1.74,-0.83; p<0.001). CONCLUSIONS: Higher initial and average regional cerebral oxygen saturation values are both associated with greater chances of achieving ROSC in patients suffering of CA. A note of caution should be made in interpreting these results due to the small number of patients and the heterogeneity in study design: larger studies are needed to clinically validate cut-offs for guiding cardiopulmonary resuscitation.
Resumo:
Seabirds act as natural reservoirs to Lyme borreliosis spirochetes and may play a significant role in the global circulation of these pathogens. While Borrelia burgdorferi sensu lato (Bbsl) has been shown to occur in ticks collected from certain locations in the North Pacific, little is known about interspecific differences in exposure within the seabird communities of this region. We examined the prevalence of anti-Bbsl antibodies in 805 individuals of nine seabird species breeding across the North Pacific. Seroprevalence varied strongly among species and locations. Murres (Uria spp.) showed the highest antibody prevalence and may play a major role in facilitating Bbsl circulation at a worldwide scale. Other species showed little or no signs of exposure, despite being present in multispecific colonies with seropositive birds. Complex dynamics may be operating in this wide scale, natural hostparasite system, possibly mediated by the host immune system and host specialization of the tick vector.
Resumo:
Variations in water volume in small depressions in Mediterranean salt marshes in Girona (Spain) are described and the potential causes for these variations analysed. Although the basins appear to be endorrheic, groundwater circulation is intense, as estimated from the difference between water volume observed and that expected from the balance precipitation / evaporation. The rate of variation in volume (VR = AV / VAt) may be used to estimate groundwater supply ('circulation'), since direct measurements of this parameter are impossible. Volume.conductivity figures can also be used to estimate the quantity of circulation, and to investigate the origin of water supplied to the system. The relationships between variations in the volume of water in the basins and the main causes of flooding are also analysed. Sea storms, rainfall levels and strong, dry northerly winds are suggested as the main causes of the variations in the volumes of basins. The relative importance assigned to these factors has changed, following the recent regulation of freshwater flows entering the system
Resumo:
The objective of this thesis was to study the removal of gases from paper mill circulation waters experimentally and to provide data for CFD modeling. Flow and bubble size measurements were carried out in a laboratory scale open gas separation channel. Particle Image Velocimetry (PIV) technique was used to measure the gas and liquid flow fields, while bubble size measurements were conducted using digital imaging technique with back light illumination. Samples of paper machine waters as well as a model solution were used for the experiments. The PIV results show that the gas bubbles near the feed position have the tendency to escape from the circulation channel at a faster rate than those bubbles which are further away from the feed position. This was due to an increased rate of bubble coalescence as a result of the relatively larger bubbles near the feed position. Moreover, a close similarity between the measured slip velocities of the paper mill waters and that of literature values was obtained. It was found that due to dilution of paper mill waters, the observed average bubble size was considerably large as compared to the average bubble sizes in real industrial pulp suspension and circulation waters. Among the studied solutions, the model solution has the highest average drag coefficient value due to its relatively high viscosity. The results were compared to a 2D steady sate CFD simulation model. A standard Euler-Euler k-ε turbulence model was used in the simulations. The channel free surface was modeled as a degassing boundary. From the drag models used in the simulations, the Grace drag model gave velocity fields closest to the experimental values. In general, the results obtained from experiments and CFD simulations are in good qualitative agreement.
Resumo:
A distinctive design feature of steam boiler with natural circulation is the presence of the steam drum which plays a role of the separator of vapor from the flow of water-and-steam mixture coming into steam drum from the furnace tubes. Steam drum with unheated downcomer tubes, deducing from it, and riser (screen/furnace tubes) inside the furnace is a closed circulation loop in which movement of water (downcomer tubes) and water-and-steam mixture (riser tubes) is organized. The movement of the working fluid is appears due to occurrence of the natural pressure, determined by the difference in hydrostatic pressure and the mass of water and water-and-steam mixtures in downcomer and riser tubes and called the driving pressure of the natural circulation: