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Intravenous alteplase is the only thrombolytic treatment approved for patients with acute ischemic stroke (AIS). Although no randomized controlled trial (RCT) has shown the superiority of tenecteplase over alteplase in AIS, tenecteplase is increasingly used off-label in Stroke Units. The purpose of the present work was to provide an up-to-date set of expert consensus statements on the use of tenecteplase in AIS.

ABSTRACTIn 2012 public service trade unions and water activists started a European Citizens’ Initiative to get the human right to water implemented in European law. It became the start of the “Right2Water” movement that successfully defended drinking water supply in the European Union against European Commission plans for liberalisation, marketisation and the subsequent threat of privatisation. In countries with a good functioning public water system, resistance against privatisation of water was high, especially in Germany, Austria and Belgium, but surprisingly this level of resistance was absent in the Netherlands, which has a similarly good and well-known public water supply system. In this article we interview two persons that have both experience in European as well as in the Netherlands’ water policies and legislation, and in water services provision. We investigate how the right to water is defined, legally decreed and socially interpreted and defended at different levels. We also investigate the apparent paradox with regards to water in the Netherlands, where people seemed very committed to and proud of their public water management, but did not stand up against a privatisation threat, whereas around the globe water privatisation plans are met with great resistance.

Recent studies demonstrated the benefit of mechanical thrombectomy (MT) plus intravenous tissue-type plasminogen activator (IV-tPA) (MT-IV-tPA) in acute ischemic stroke. This study aimed to estimate the cost-utility of MT-IV-tPA compared with IV-tPA alone from the perspective of the French National Health Insurance.

Zooplankton vertical migration enhances the efficiency of the ocean biological pump by translocating carbon (C) and nitrogen (N) below the mixed layer through respiration and excretion at depth. We measured C and N active transport due to diel vertical migration (DVM) in a Svalbard fjord at 79°N. Multifrequency analysis of backscatter data from an Acoustic Zooplankton Fish Profiler moored from January to September 2014, combined with plankton net data, showed that Thysanoessaspp. euphausiids made up > 90% of the diel migrant biomass. Classical synchronous DVM occurred before and after the phytoplankton bloom, leading to a mismatch with intensive primary production during the midnight sun. Zooplankton DVM resulted in C respiration of 0.9 g m−2and ammonium excretion of 0.18 g N m−2below 82 m depth between February and April, and 0.2 g C m−2and 0.04 g N m−2from 11 August to 9 September, representing > 25% and > 33% of sinking flux of particulate organic carbon and nitrogen, respectively. Such contribution of DVM active transport to the biological pump in this high‐Arctic location is consistent with previous measurements in several equatorial to subarctic oceanic systems of the World Ocean. Climate warming is expected to result in tighter coupling between DVM and bloom periods, stronger stratification of the Barents Sea, and northward advection of boreal euphausiids. This may increase the role of DVM in the functioning of the biological pump on the Atlantic side of the Arctic Ocean, particularly where euphausiids are or will be prevalent in the zooplankton community.

BackgroundIt has been amply demonstrated that endovascular procedures can be successful treatment for stroke, both in terms of revascularization and clinical outcome. There is not, however, a published comparison of any histological or ultrastructural damage to the vessels that may be caused by a direct aspiration first pass technique (ADAPT) or stent retrievers (SR) used in these procedures. This study analyses and compares acute damage to the arterial wall caused by ADAPT or SR.Material and methodsDamage to the walls of swine extracranial arteries was evaluated after ADAPT with the Penumbra system or thrombectomy with an SR (Solitaire 6×30). The procedures were performed after injecting thrombi into the selected arteries (arteries with diameters similar to those of the human internal carotid artery and first segment of the middle cerebral artery). After the procedures, the animal was euthanized and 12 arterial samples were obtained for analysis by optical and electronic microscopy.ResultsTissue samples from the vessels treated with SR showed almost complete loss of endothelium, thickening of the internal elastic lamina, and degeneration of the elastic fibers of the bordering lamina media and adventitia. In contrast, tissue samples of the vessels treated with ADAPT had a clear integral internal elastic lamina and uninterrupted endothelial lining, although cell alignment was altered and there were surface lacerations due to manipulation of the samples.ConclusionsBoth techniques caused acute damage to the vessel walls, however, thrombectomy with SR appeared to be more harmful to all layers of the arterial wall, particularly the endothelium.

Les dispositifs médicaux de neurostimulation vagale (NSV) sont utilisés pour traiter les épilepsies avérées invalidantes et pharmaco-résistantes de l’adulte et de l’enfant. Des courants électriques de faible intensité sont générés périodiquement au niveau du nerf vague. Les effets indésirables sont notamment : l’enrouement (37 %), le mal de gorge (11 %), la toux (7 %) et la dyspnée (6 %). Ces effets peuvent être réduits après réglage du dispositif. Le patient peut être acteur du stimulateur en l’allumant ou l’éteignant afin d’anticiper la survenue d’une crise ou réduire les effets indésirables de la stimulation. Ces éléments sont évocateurs d’un intérêt de formation des patients à ce dispositif implanté, via un entretien pharmaceutique (EP) de sortie.

We present the case of a 43-year-old man with acute visual loss due to an optic chiasm cavernoma. Our clinical and imaging findings quickly led us to this diagnosis. As a clinical improvement spontaneously occurred soon after the initial diagnosis, we decided not to perform any surgical treatment. The visual evolution was satisfactory and, to date after a 36-months follow-up, no clinical worsening has been reported. We present this clinical case regarding our approach, primarily a close follow-up, as well as a review of the literature.

Case report and review of the literature.

Recent studies predict that the Arctic Ocean will have ice-free summers within the next 30 years. This poses a significant challenge for the marine organisms associated with the Arctic sea ice, such as marine mammals and, not least, the ice-associated crustaceans generally considered to spend their entire life on the underside of the Arctic sea ice. Based upon unique samples collected within the Arctic Ocean during the polar night, we provide a new conceptual understanding of an intimate connection between these under-ice crustaceans and the deep Arctic Ocean currents. We suggest that downwards vertical migrations, followed by polewards transport in deep ocean currents, are an adaptive trait of ice fauna that both increases survival during ice-free periods of the year and enables re-colonization of sea ice when they ascend within the Arctic Ocean. From an evolutionary perspective, this may have been an adaptation allowing success in a seasonally ice-covered Arctic. Our findings may ultimately change the perception of ice fauna as a biota imminently threatened by the predicted disappearance of perennial sea ice.

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Several different system balance methods and programmes have been developed and used for decades in the refrigeration industry to design refrigeration circuits and components. One of the oldest methods is the graphical—analytical method, developed and used long before computers and even calculators became standard engineering tools. The method is relatively easy and it helps to design and choose proper components. It can be successfully used today in the computer age for a better understanding of the refrigeration system behaviour, enabling the designer to see and evaluate major components, system characteristics, and system trends.This article will introduce the graphical—analytical method for the simplest refrigeration systems and later extend it to more complex refrigeration systems.

The main final goal of the treatment of brain AVMs is to prevent bleeding and to obtain a complete occlusion of the nidus. The strategy of treatment of brain arteriovenous malformations (AVM) has to be defined by a multidisciplinary team and will usually combine several modalities (surgery, radiosurgery, embolization). Embolization is generally the first step of treatment. Occasionally embolization is able to completely occlude a small AVM.Otherwise embolization is the first step before surgery or radiosurgery. Several embolic agents have been proposed for embolization of brain AVMs like particles or cyanoacrylates. The main disadvantage of particles is the high frequency of recanalization.The cyanoacrylates are probably more appropriate, providing a permanent occlusion. However, due to the polymerizing characteristics of the glue, the time of injection is relatively short (few seconds or minutes) and a complete or substantial occlusion of the nidus is difficult to obtain, especially in the case of medium or largesized AVMs.Onyx is a nonadhesive liquid polymer made of a mixture of ethylene-vinyl-alcohol copolymer and dimethylsulfoxide. The theoretical advantage of a nonadhesive liquid is to eliminate the risk of gluing the microcatheter and subsequently to perform a more durable injection with a larger amounts of agent delivered in a single injection.Several French centers have undertaken a prospective, multicentric study to evaluate the clinical value of Onyx in embolization of brain AVMs. As required, 50 patients were included. Preliminary results are presented regarding the first 48 patients, the last 2 patients being included after writing of this paper.The treatment is now completed in 15 patients. As expected, it was possible with Onyx to perform long duration injections (5 to 70 minutes with a mean of 34 minutes).Volumes injected per session were also important (0.25 to 6 ml with a mean of 1.6 ml). According to the clinical experience of the centers, duration and volume injected were most important with Onyx than with cyanoacrylates. Out of the 15 patients for whom embolization is now completed, 14 had a percentage of occlusion of the nidus greater than 60% (with 2 complete occlusion).

Potent nanomolar inhibitors of Staphylococcus aureus methionyl tRNA synthetase have been derived from a file compound high throughput screening hit. Optimized compounds show excellent antibacterial activity against staphylococcal and enterococcal pathogens, including strains resistant to clinical antibiotics. Compound 11 demonstrated in vivo efficacy in an S. aureus rat abscess infection model.

We report the case of an arteriovenous malformation (AVM) of the vein of Galen diagnosed in utero at the 34th week of gestation by ultrasound and MRI. Following interdisciplinary advice, the family decided to terminate the pregnancy. This was carried out in the 36th week of gestation. Mascroscopic study of the fetus confirmed the in utero diagnosis: considerable dilatation of the cerebral arteries, the Galen vein and the anteroinferior sinuses. Based on the correlation of pre and post natal examinations, this study highlights the accuracy of in uteroMRI, coupled with ultrasound scanning in the diagnosis of an AVM of the Galen vein. It provides specific information on the degree of cerebral impairment. MRI in uterohelps in decision-making for pregnancy termination.

Cytochrome P450 partial sequences were isolated by PCR using genomic DNA from two hymenopteran insects of agronomical importance, Trichogramma cacœciae, a parasitoid wasp, and Apis mellifera, the honeybee. Four new P450 genes were identified: one honeybee gene belongs to the CYP4 family and was named CYP4G11; the three other genes were from Trichogramma and belong to the CYP4 family (CYP4G12) and to a novel family, the CYP48 one (CYP48A1 and CYP48A2). The four genes contain a short intron (72–95 bp) at the same position as already described for other insect species. The two genes CYP48A1 and CYP48A2 have a supernumary intron (57–71 bp) upstream the first one. Only the two CYP4 genes were constitutively transcribed, at a high level for CYP4G12 and at a low level for CYP4G11. No expression was observed for CYP48A1 and CYP48A2.

Biochemical markers measured in marine animals can be investigated to improve their detection, quantification and to understand the significance of their exposure to contaminants in the marine environment. The main objectives of the BIOMAR project are the following: (i) Getting a better knowledge about biological mechanisms developed by marine organisms (mussel, fish, sea star, sea urchin) in coastal environments under the effects of contaminants, by in virroand in vivoexperiments; (ii) Investigation of the relationship between biochemical markers measured in marine organisms and chemical pollutants (aromatic compounds, PCB, heavy metals) determined in the marine environment (sediment, water and biota); (iii) Characterization of the criteria and physiological/biochemical/cellular parameters for an efficient coastal contamination biomonitoring program based on biomarkers; and (iv) Automation of biomarker measurements for routine and onboard analysis. An overview of the results is presented from laboratory and field experiments with multimarker and multispecies approaches as the main objective.

Abstract: Predation has been demonstrated to be of fundamental importance in structuring benthic communities in the intertidal zone. The aim of the present investigation was to elucidate some of the effects of predation on structuring communities in unvegetated subtidal sediments. Field manipulative cage experiments were performed on sediment in the inner part of the Oslofjord (Norway), where the species composition was typical for a moderately organically enriched sediment. Sediment from this area was transferred to an area not suspected a priori to be seriously affected by organic pollution, and the effect of predation on the fauna was evaluated. Predation effects were not observed in the Oslofjord experiments partially because of extensive obstruction of recruitment to the sediment by settlement ofPolydora antennata on the cage; however, further experiments are in progress in this area. No such settling was observed in the unpolluted area. Here 63 taxonomic groups were identified, 57 in the control and 50 in the cages; 43 taxonomic groups were found in both the cage and the control. The total number of individuals was significantly higher in the cage (4779) than in the control (2849). The fauna recruited to the sediment in the cage responded to decreased predation by macropredators by a significant reduction in diversity. Of the 10 most abundant groups 3 (Tellinacea, Syllidae andPholo minuta) were significantly more abundant in the cage than in the control; 3 others (Prionospio malmgreni, Microphthalmus abberans and Paraonidea) were significantly more abundant in the control. It is concluded that in an unpolluted area predation is an important factor in controlling numbers of at least some of the most abundant species. However, the effect of predation does not seem to be of the same importance in the subtidal as has previously been recognized for unvegetated intertidal mudflats.

The effect of selection for methidathion resistance on fitness components of aP. persimilisstrain was analysed by different means. The resistant strain was compared with the susceptible one from which it was selected. The life history and some parameters essential to the successful use of this species in biological control (voracity, resistance to starvation and drought) were analysed. Methidathion resistance was followed for 6 months under rearing conditions free of insecticide in the resistant and in a mixed strain. The investigations showed that the fitness of resistant mites did not seem altered by methidathion selection. It thus appears possible to increase pesticide resistance in beneficial arthropods without adversely affecting their main fitness components.

The role of beta3- and other putative atypical beta-adrenoceptors in human white adipocytes and right atrial appendage has been investigated using CGP 12177 and novel phenylethanolamine and aryloxypropanolamine beta3-adrenoceptor (beta3AR) agonists with varying intrinsic activities and selectivities for human cloned betaAR subtypes. The ability to demonstrate beta1/2AR antagonist-insensitive (beta3 or other atypical betaAR-mediated) responses to CGP 12177 was critically dependent on the albumin batch used to prepare and incubate the adipocytes. Four aryloxypropanolamine selective beta3AR agonists (SB-226552, SB-229432, SB-236923, SB-246982) consistently elicited beta1/2AR antagonist-insensitive lipolysis. However, a phenylethanolamine (SB-220646) that was a selective full beta3AR agonist elicited full lipolytic and inotropic responses that were sensitive to beta1/2AR antagonism, despite it having very low efficacies at cloned beta1- and beta2ARs. A component of the response to another phenylethanolamine selective beta3AR agonist (SB-215691) was insensitive to beta1/2AR antagonism in some experiments. Because no [corrected] novel aryloxypropanolamine had a beta1/2AR antagonist-insensitive inotropic effect, these results establish more firmly that beta3ARs mediate lipolysis in human white adipocytes, and suggest that putative 'beta4ARs' mediate inotropic responses to CGP 12177. The results also illustrate the difficulty of predicting from studies on cloned betaARs which betaARs will mediate responses to agonists in tissues that have a high number of beta1- and beta2ARs or a low number of beta3ARs.

The aim of the investigation was to see if the histological diagnosis of brain tumors showing an intermediate degree of malignancy can be improved by the measurement ofl-a-alanine inhibition of pyruvate kinase isoenzymes. The inhibition of pyruvate kinase activity was measured in 51 gliomas with different grades of malignancy. It was confirmed that benign tumors have a low level of inhibition (less than 50%) and that the more malignant the tumor, the higher the level of inhibition became, reaching more than 75%. However, when grade II and III astrocytomas and grade II and III oligodendrogliomas were analyzed, their level of inhibition was found to be variable. Grade II showed low and moderate levels of inhibition and grade III moderate and high levels. In turn, inhibition levels ranging from 50 to 75% were not only found in brain tumors with an intermediate grade of malignancy, but also in a number of benign and malignant tumors. When the survival times of patients with brain tumors were compared with both the histological diagnosis and pyruvate kinase inhibition, the prediction of the survival time on the basis of low and high levels of inhibition correlated well with the histological diagnosis. In contrast, when moderate levels of inhibition were measured, the prediction of the patients' survival remained uncertain and no improvement was found in the prediction for tumors showing an intermediate degree of malignancy on the basis of histology.

Résumé: La toxicité du méthidathion a été mesurée sur 7 souches dePhytoseiulus persimilis provenant de collections de laboratoire, d'unités de production ou du terrain. Les résultats obtenus se sont avérés être très variables: la CL50 de la souche la plus résistante est 100 fois plus élevée que celle de la souche la plus sensible. Chaque souche a ensuite été sélectionnée pour la résistance à cet insecticide; toutes les souches ont répondu à la sélection et ont atteint des niveaux de résistance similaires. Elles ont ensuite été mélangées, à nouveau sélectionnées pour la résistance au méthidathion et à d'autres insecticides et utilisées dans les programmes de lutte intégrée. La résistance a pu ainsi être légèrement augmentée et la souche obtenue, bien qu'encore affectée par le méthidathion sur le terrain, n'est plus complètement éliminée par les traitements et est moins sensible aux résidus présents sur les feuilles.

Abstract: Two well-known lower bounds to the reliability in classical test theory, Guttman's lambda2 and Cronbach's coefficient alpha, are shown to be terms of an infinite series of lower bounds. All terms of this series are equal to the reliability if and only if the test is composed of items which are essentially tau-equivalent. Some practical examples, comparing the first 7 terms of the series, are offered. It appears that the second term (lambda2) is generally worth-while computing as an improvement of the first term (alpha) whereas going beyond the second term is not worth the computational effort. Possibly an exception should be made for very short tests having widely spread absolute values of covariances between items. The relationship of the series and previous work on lower bound estimates for the reliability is briefly discussed.

Esterase B1 activity in Culex pipiens mosquitoes was strongly inhibited by oxidized organophosphates (OP), but not by nonoxidized forms or by carbamates. Inhibition by chlorpyrifos oxon and paraoxon remained total during the 2 hr following the removal of free insecticide molecules, indicating that hydrolysis by esterase B1 is either very slow or absent. This hypothesis was confirmed by comparing the fate of [14C]chlorpyrifos in larvae of strains TEM-R (with the over-produced esterase B1) and MSE (lacking an overproduced esterase). As expected, large quantities of chlorpyrifos oxon were observed in the two strains, but no other metabolite was found in TEM-R. It is concluded that esterase B1 confers resistance at least to diethyl OPs through sequestering rather than metabolism, as is also the case with the overproduced esterase E4 of Myzus persicae.Copyright 1993, 1999 Academic Press

1. introduction. Quite pronounced eddy motion is apt to occur in certain hydraulic structures when a transition occurs from free-surface to pressure flow, and other abnormal flow effects. (especially vortex "streamers') are also observed, even in pressure flows. Eddies on a free surface sometimes grow to the point of forming a kind of "funnel" or vortex at one point. Air is sometimes entrained in the central depression, and when this happens, rotational speeds increase very sharply towards the vortex centre. Such phenomena can be observed in orifice flows (tank drains, lock chambers, power tunnel intakes, flow under a gate, reservoir or river intakes, etc.) or in pumping plant, irrespective of the pump intake orifice design (Fig. 1). 2. Aims of this study. In the absence of precise theories whereby the likelihood of vortex formation might be predicted for each particular case, many manufacturers and research laboratories undertake several research programmes every year in an attempt to find a way of preventing vortex formation in dam water intakes in rivers or in pump intake chambers. Conditions governing vortex formation not only depend on the hydraulic flow conditions (depth or head of water, rate of flow, etc.) and ambient conditions (especially fluid temperatures) but also on the chamber design (shaped intake or suction chamber). Ideal intake or suction chamber outlines cannot always be achieved, for civil engineering and imperative cost requirements almost invariably make it necessary to put up with considerable misalignment of the supply canal centre line and the intake or pump position, resulting in an appreciable kinetic moment and vortex formation. The same types of test are repeated over and over again with the same imperfect devices such as floating rafts, strainers, deflecting panels at various angles, etc., until satisfactory results are finally obtained. An attempt has now been made by "Société Hydrotechnique de France" ("Machines Section") to collate the experience of various manufacturers and laboratories for the common good. The three main points retained for consideration in this study were the following: (i) Vortex formation conditions (and conditions for other abnormal flow effects, where applicable) ; (ii) Anti-vortex devices; (iii) Vortex similitude. The most characteristic special cases have been retained out of the replies received (they are summed up in "card-index" fashion in an appendix hereto) so that manufacturers and laboratories may acquaint themselves not only with the vortex formation conditions for such cases, but also with successful counter-measures. It is a good thing to thus be able to avoid the considerable amount of costly trial-and-error work associated with the search for a solution, which may not even then be entirely satisfactory. It is also thought the attached reference list to the principal current research into the subject may be of interest. 3. Vortex formation conditions. Vortex formation depends on numerous parameters, notably hydraulic conditions (depth or head of water, rate of flow, etc.) and the geometry of the installation. By analysing information obtained, experimental data from the Chatou Test Centre, and published data (see bibliographical reference list herewith) it has been possible to determine the critical head or depth of water above the bellmouth intake beyond which vortices no longer entrain air. Especially in the case of vortices formed by vertical rising suction flow, the tests have shown up the effect of chamber geometry and-for example-variation of any of the following (Fig. 2) : (i) Distance from bellmouth to floor ; (ii) Distance from the walls ; (iii) Pump position in the sump ; (iv) Bellmouth diameter ; (v) Pipe diameter ; (vi) Chamber intake width. Other forms of abnormal now liable to appear in a water intake are also worth noting, for instance the formation of a vortex "streamer" underneath the bellmouth, with large quantities of bubbles (Fig. 3 and 4). 4. Anti-vortex devices. Contributors have drawn attention to numerous such devices, and references to others are found in published material (see bibliographical reference list herewith). Most are designed to prevent air entrainment and do not eliminate eddies near the intake orifice, as would strictly speaking be desirable for ideal pump intake conditions. This has led to the development of a special device consisting of lateral vertical expanded metal screens by the Chatou Research Centre, which are positioned in the suction chamber parallel to the flow and symmetrically to either side of the pump (or of the suction orifice in the case of a drain) (see sketches, Figs 5 a-b). An expanded metal screen comprises a large number of identical diamond-shaped meshes which, seen in cross-section, appear as a series of parallel blades ; to ensure efficient flow deflection, the "strap" of each such "blade" must be fairly wide. In addition, the longer mesh diagonal must lie parallel to the eddy vector, i.e. nearly always vertical. The lack of symmetry of this metal device thus enables lateral frictional resistance to any flow to be reduced to practically nothing in the normal direction of flow, i.e. from the intake sluice towards the suction orifice. This resistance becomes very great (and the flow may be deflected) with the flow occurring in the reverse direction, as is invariably associated with eddy formation (Fig. 5 c). This being so, experience has shown that provided the expanded metal screen has the requisite characteristics, vortex formation and 'streamer' effects underneath the bellmouth can be prevented completely by such screens extending over the full depth of water in the chamber. Visual observation then shows completely calm, steady flow throughout the chamber. Suitable screen characteristics depend on hydraulic conditions (depth of water, rate of flow etc.) and the initial fluid circulation value at the chamber inlet. These can be determined accurately by scale model tests, but a rough solution to the problem can be based on established practical solutions along the lines listed in the "card-index" herewith. (Slips II B 4 to II B 7.) As no flow passes, through the screens during normal plane operation, loss of head due to the device is negligible ; it was found to be well within normal experimental error on all the models tested. Full panels in lieu of these screens do not eliminate the vortex, but if placed behind the screens (on the opposite side to the suction orifice) they do not affect their beneficial action, and all eddy motion is still eliminated as before. This being so, vertical expanded-metal screens are able to inhibit vortex formation in suction chambers of any shape. A set of vertical screens facing in the direction of flow can thus be arranged by each suction orifice of an intake or in a chamber of any shape (examples are given in the appendix with the article). In the particular case of tank-fed vertical pumps, an additional vertical screen is placed behind the pump and connecting to the two lateral screens, in order to prevent formation of an unlimited dead water area behind the pump. The meshes of the third screen face in a direction ensuring a total absence of eddy formation. The expanded metal characteristics (mesh pitch 'strap' width, etc.) and screen spacing depend on the intensity of the initial circulation at the basin inlet, also on head of water and rate of flow. Some care is required in placing the expanded metal screens on the model (and subsequantly also on the prototype). Vortex formation is not prevented if the mesh is positioned incorrectly or if the screens are unsymmetrical with respect to each other, by virtue of the very process whereby correctly installed screens prevent vortex formation. This system also eliminates non-aerated eddy motion (overall motion on the free surface, 'streamers', rotary motion underneath the bellmouth, etc.) while regulating the flow with negligible loss of head. A further advantage of these screens is that they cannot clog up with dirt in the water as there is no flow through them. They have already been fitted in numerous installations and have invariably given the same efficient service as on the model. 5. Vortex similitude. Though this very complicated problem is beyond the scope of this study, it was nevertheless considered interesting to approach it because of the importance of comparing model and prototype when designing an anti-vortex device. Similitude conditions depend on the criterion considered for the comparison, which could be one of the following : - (i) Conditions for the formation of the initial hyperbolic portion of the vortex "funnel" on the free surface ; (ii) Conditions for initial air entrainment ; (iii) Air-core vortex frequency and duration under given conditions. The choice of different comparative criteria can thus explain the numerous differences between the similitude criteria suggested by various laboratories and in published work. These criteria are analysed, followed by a description of the main results obtained at Chatou Research Centre (Figs 6 to 9). An experimental method was required whereby the characteristics of a vortex might accurately be determined at any given instant, from the moment of initial depression formation to that of air entrainment. The main difficulties in finding such a method were associated with vortex instability in both space and time. Direct methods of determining the vortex 'funnel' profile (point gauges, pressure pick-ups) could not he considered, as a vortex continually changes its position on the free surface, and also because of the upsetting effect of such instruments upon the flow-even if in miniaturized form. Only an optical method could be practicable, therefore, but straight photography of the vortex shape and length also had to he given up because of its very considerable error when applied to shallow vortices. The 'refracted ray' method developed at Chatou in 1960 gives the requisite results. It is based on the optical phenomenon whereby a caustic surface forms when light rays are diverted in passing through the dioptic air-water surface of revolution of the vortex 'funnel'. It is then merely necessary to mark out the chamber floor with a suitable scale and to measure the diameter of the dark circular patch formed by the intersection of the caustic surface and the chamber floor (see Fig. 7). The actual measurement can be done by an appropriate cinematographic recording method. The advantage of this method is that it enables an experimental relationship to be established between circulation strength around the vortex (determined from the patch dimensions) the depth of water in the chamber, and the pump intake flow. Tests are still in progress on the subject, but it is already quite clear from results so far that : - (i) Formation of the hyperbolic upper part of the vortex 'funnel' on the free surface definitely appears to comply with Froude similitude requirements ; (ii) Given equal velocities on the model and prototype, the initial air entrainment process would also comply with similitude requirements.

1. introduction. Quite pronounced eddy motion is apt to occur in certain hydraulic structures when a transition occurs from free-surface to pressure flow, and other abnormal flow effects. (especially vortex "streamers') are also observed, even in pressure flows. Eddies on a free surface sometimes grow to the point of forming a kind of "funnel" or vortex at one point. Air is sometimes entrained in the central depression, and when this happens, rotational speeds increase very sharply towards the vortex centre. Such phenomena can be observed in orifice flows (tank drains, lock chambers, power tunnel intakes, flow under a gate, reservoir or river intakes, etc.) or in pumping plant, irrespective of the pump intake orifice design (Fig. 1). 2. Aims of this study. In the absence of precise theories whereby the likelihood of vortex formation might be predicted for each particular case, many manufacturers and research laboratories undertake several research programmes every year in an attempt to find a way of preventing vortex formation in dam water intakes in rivers or in pump intake chambers. Conditions governing vortex formation not only depend on the hydraulic flow conditions (depth or head of water, rate of flow, etc.) and ambient conditions (especially fluid temperatures) but also on the chamber design (shaped intake or suction chamber). Ideal intake or suction chamber outlines cannot always be achieved, for civil engineering and imperative cost requirements almost invariably make it necessary to put up with considerable misalignment of the supply canal centre line and the intake or pump position, resulting in an appreciable kinetic moment and vortex formation. The same types of test are repeated over and over again with the same imperfect devices such as floating rafts, strainers, deflecting panels at various angles, etc., until satisfactory results are finally obtained. An attempt has now been made by "Société Hydrotechnique de France" ("Machines Section") to collate the experience of various manufacturers and laboratories for the common good. The three main points retained for consideration in this study were the following: (i) Vortex formation conditions (and conditions for other abnormal flow effects, where applicable) ; (ii) Anti-vortex devices; (iii) Vortex similitude. The most characteristic special cases have been retained out of the replies received (they are summed up in "card-index" fashion in an appendix hereto) so that manufacturers and laboratories may acquaint themselves not only with the vortex formation conditions for such cases, but also with successful counter-measures. It is a good thing to thus be able to avoid the considerable amount of costly trial-and-error work associated with the search for a solution, which may not even then be entirely satisfactory. It is also thought the attached reference list to the principal current research into the subject may be of interest. 3. Vortex formation conditions. Vortex formation depends on numerous parameters, notably hydraulic conditions (depth or head of water, rate of flow, etc.) and the geometry of the installation. By analysing information obtained, experimental data from the Chatou Test Centre, and published data (see bibliographical reference list herewith) it has been possible to determine the critical head or depth of water above the bellmouth intake beyond which vortices no longer entrain air. Especially in the case of vortices formed by vertical rising suction flow, the tests have shown up the effect of chamber geometry and-for example-variation of any of the following (Fig. 2) : (i) Distance from bellmouth to floor ; (ii) Distance from the walls ; (iii) Pump position in the sump ; (iv) Bellmouth diameter ; (v) Pipe diameter ; (vi) Chamber intake width. Other forms of abnormal now liable to appear in a water intake are also worth noting, for instance the formation of a vortex "streamer" underneath the bellmouth, with large quantities of bubbles (Fig. 3 and 4). 4. Anti-vortex devices. Contributors have drawn attention to numerous such devices, and references to others are found in published material (see bibliographical reference list herewith). Most are designed to prevent air entrainment and do not eliminate eddies near the intake orifice, as would strictly speaking be desirable for ideal pump intake conditions. This has led to the development of a special device consisting of lateral vertical expanded metal screens by the Chatou Research Centre, which are positioned in the suction chamber parallel to the flow and symmetrically to either side of the pump (or of the suction orifice in the case of a drain) (see sketches, Figs 5 a-b). An expanded metal screen comprises a large number of identical diamond-shaped meshes which, seen in cross-section, appear as a series of parallel blades ; to ensure efficient flow deflection, the "strap" of each such "blade" must be fairly wide. In addition, the longer mesh diagonal must lie parallel to the eddy vector, i.e. nearly always vertical. The lack of symmetry of this metal device thus enables lateral frictional resistance to any flow to be reduced to practically nothing in the normal direction of flow, i.e. from the intake sluice towards the suction orifice. This resistance becomes very great (and the flow may be deflected) with the flow occurring in the reverse direction, as is invariably associated with eddy formation (Fig. 5 c). This being so, experience has shown that provided the expanded metal screen has the requisite characteristics, vortex formation and 'streamer' effects underneath the bellmouth can be prevented completely by such screens extending over the full depth of water in the chamber. Visual observation then shows completely calm, steady flow throughout the chamber. Suitable screen characteristics depend on hydraulic conditions (depth of water, rate of flow etc.) and the initial fluid circulation value at the chamber inlet. These can be determined accurately by scale model tests, but a rough solution to the problem can be based on established practical solutions along the lines listed in the "card-index" herewith. (Slips II B 4 to II B 7.) As no flow passes, through the screens during normal plane operation, loss of head due to the device is negligible ; it was found to be well within normal experimental error on all the models tested. Full panels in lieu of these screens do not eliminate the vortex, but if placed behind the screens (on the opposite side to the suction orifice) they do not affect their beneficial action, and all eddy motion is still eliminated as before. This being so, vertical expanded-metal screens are able to inhibit vortex formation in suction chambers of any shape. A set of vertical screens facing in the direction of flow can thus be arranged by each suction orifice of an intake or in a chamber of any shape (examples are given in the appendix with the article). In the particular case of tank-fed vertical pumps, an additional vertical screen is placed behind the pump and connecting to the two lateral screens, in order to prevent formation of an unlimited dead water area behind the pump. The meshes of the third screen face in a direction ensuring a total absence of eddy formation. The expanded metal characteristics (mesh pitch 'strap' width, etc.) and screen spacing depend on the intensity of the initial circulation at the basin inlet, also on head of water and rate of flow. Some care is required in placing the expanded metal screens on the model (and subsequantly also on the prototype). Vortex formation is not prevented if the mesh is positioned incorrectly or if the screens are unsymmetrical with respect to each other, by virtue of the very process whereby correctly installed screens prevent vortex formation. This system also eliminates non-aerated eddy motion (overall motion on the free surface, 'streamers', rotary motion underneath the bellmouth, etc.) while regulating the flow with negligible loss of head. A further advantage of these screens is that they cannot clog up with dirt in the water as there is no flow through them. They have already been fitted in numerous installations and have invariably given the same efficient service as on the model. 5. Vortex similitude. Though this very complicated problem is beyond the scope of this study, it was nevertheless considered interesting to approach it because of the importance of comparing model and prototype when designing an anti-vortex device. Similitude conditions depend on the criterion considered for the comparison, which could be one of the following : - (i) Conditions for the formation of the initial hyperbolic portion of the vortex "funnel" on the free surface ; (ii) Conditions for initial air entrainment ; (iii) Air-core vortex frequency and duration under given conditions. The choice of different comparative criteria can thus explain the numerous differences between the similitude criteria suggested by various laboratories and in published work. These criteria are analysed, followed by a description of the main results obtained at Chatou Research Centre (Figs 6 to 9). An experimental method was required whereby the characteristics of a vortex might accurately be determined at any given instant, from the moment of initial depression formation to that of air entrainment. The main difficulties in finding such a method were associated with vortex instability in both space and time. Direct methods of determining the vortex 'funnel' profile (point gauges, pressure pick-ups) could not he considered, as a vortex continually changes its position on the free surface, and also because of the upsetting effect of such instruments upon the flow-even if in miniaturized form. Only an optical method could be practicable, therefore, but straight photography of the vortex shape and length also had to he given up because of its very considerable error when applied to shallow vortices. The 'refracted ray' method developed at Chatou in 1960 gives the requisite results. It is based on the optical phenomenon whereby a caustic surface forms when light rays are diverted in passing through the dioptic air-water surface of revolution of the vortex 'funnel'. It is then merely necessary to mark out the chamber floor with a suitable scale and to measure the diameter of the dark circular patch formed by the intersection of the caustic surface and the chamber floor (see Fig. 7). The actual measurement can be done by an appropriate cinematographic recording method. The advantage of this method is that it enables an experimental relationship to be established between circulation strength around the vortex (determined from the patch dimensions) the depth of water in the chamber, and the pump intake flow. Tests are still in progress on the subject, but it is already quite clear from results so far that : - (i) Formation of the hyperbolic upper part of the vortex 'funnel' on the free surface definitely appears to comply with Froude similitude requirements ; (ii) Given equal velocities on the model and prototype, the initial air entrainment process would also comply with similitude requirements.

The main result establishes upper bounds on the rank of $ {H_1}$-manifolds with fake $ 3$ of closed orientable $ 3$-cells. As a consequence we get that a $ 3$-cell.

Plusieurs essais cliniques randomisés ont prouvé l’efficacité de la thrombectomie en association avec la thrombolyse (T+T) comparativement à la thrombolyse seule dans la prise en charge des infarctus cérébraux (IC). Bien que pratiquée en France depuis 2015, la T+T n’est pas remboursée par l’Assurance maladie. Pour aider à la décision de remboursement, nous proposons une évaluation médico-économique de la thrombectomie, dans la perspective de l’Assurance maladie.