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Sea levels variations in the upper part of estuary are traditionally approached by relying on refined numerical simulations with high computational cost. As an alternative efficient and rapid solution, we assessed here the performances of two types of machine learning algorithms: (i) multiple regression methods based on linear and polynomial regression functions, and (ii) an artificial neural network, the multilayer perceptron. These algorithms were applied to three-year observations of sea levels maxima during high tides in the city of Landerneau, in the upper part of the Elorn estuary (western Brittany, France). Four input variables were considered in relation to tidal and coastal surge effects on sea level: the French tidal coefficient, the atmospheric pressure, the wind velocity and the river discharge. Whereas a part of these input variables derived from large-scale models with coarse spatial resolutions, the different algorithms showed good performances in this local environment, thus being able to capture sea level temporal variations at semi-diurnal and spring-neap time scales. Predictions improved furthermore the assessment of inundation events based so far on the exploitation of observations or numerical simulations in the downstream part of the estuary. Results obtained exhibited finally the weak influences of wind and river discharges on inundation events.

Optimum design and location of wave energy converters in the marine environment require accurate assessments of the spatio-temporal variability of the available wave energy flux. However, numerical hindcast databases (commonly exploited for these long-term evaluations) integrate a restricted number of parameters such as the significant wave height H s or the peak period T p . Computation of wave power density from hindcast database is thus conducted by relying on simplified formulations derived from approximations of the group velocity and the wave energy spectrum. The present investigation quantified the biases in wave power computation from two standard formulations, based on the energy period and the peak period, respectively. The analysis relied on NOAA observations in 17 locations of the North-West Atlantic, the Gulf of Mexico and the Caribbean Sea. Whereas the energy-period formulation was a very good approximation of the wave power density in deep waters, the peak-period formulation (with a default calibration coefficient α = 0.9 ) overestimated locally, by more than 8 % , the available wave energy flux. A refined distribution of α against classes of H s and T p was established to reduce these differences, decreasing the relative difference from 9.9 % to 0.3 % off the Greater Antilles.

Numerical investigations dedicated to the impact of wave power variability on energy conversion were mainly conducted in the European shelf seas where a considerable amount of technological devices was developed. We complemented these studies by exploiting a 31-year consistent hindcast database of the wave climate, assessed against observations in 41 locations, in the North-West Atlantic, the Gulf of Mexico and the Caribbean Sea. With an exception in the Caribbean Sea where wave power density increased under the influence of an easterly zonal wind, a clear contrast was exhibited in the available wave energy flux between the oceanic energetic regions of the North-West Atlantic and the semi-enclosed basins, protected from incoming waves conditions by a series of islands. The analysis revealed furthermore contrasting wave climates characterized by (i) significant temporal variability in the Gulf of Mexico and the northern oceanic region off the USA East Coast, and (ii) more moderated variations in the Caribbean Sea off Colombia and the southern oceanic area off the Lesser Antilles. A generic method, independent from the device technology, was finally adopted to assess the effects of resource variability on energy output and converters performances. The area off the Lesser Antilles appeared particularly interesting to supply, at reduced installed capacity but with more regular waves conditions, renewable energy within surrounding island territories.

Refined numerical wave energy resource assessments are required to reduce uncertainties in the evaluation of available power and energy production. However, to restrict the computational cost, a great part of wave hindcast simulations cover a limited time range (below ten years) or rely on coarse spatial resolutions while routinely ignoring tide-induced modulations in wave conditions. Complementing resource assessments conducted in the North-West European shelf seas, we here exploited a 27-year hindcast database (1994–2020) set up at a spatial resolution of 200 m along the coast of France and integrating the effects of tidal currents on waves. This evaluation was conducted in three water depths from offshore to nearshore (60, 40 and 20 m) around Brittany, one of the most energetic regions along the coast of France. We investigated the performances of a series of thirteen state-of-the-art wave energy converters with respect to installation depth range. Beyond confirming the interest of western Brittany in energy exploitation, the results exhibited the first ranking between devices, thus promoting the interests of Oceantec in offshore waters (60 m), Wave Dragon in intermediate waters (40 m), and Oyster and WaveStar C6 in shallow waters (20 m).

International audience; Background - Clinicians traditionally warn patients of pain before peripheral i.v. cannulation (PIVC). However, using words related to pain or undesirable experiences can result in greater pain and anxiety. The use of positive words can improve pain perception and subjective patient experience. We aimed to compare the effects of three types of communication, including hypnotic communication, on pain, comfort, and anxiety in patients during PIVC. Methods - The Effect of Language and Confusion on Pain During Peripheral Intravenous Catheterization (KTHYPE) trial is a randomised, parallel, single-blind, multicentre study of patients undergoing PIVC on the dorsal face of the hand before surgery. Patients from three hospitals were randomly allocated to one of three groups: PIVC performed with a hypnosis technique (hypnosis group), negative connotation (nocebo group), and neutral connotation (neutral group). The primary outcome measure was the occurrence of pain measured with a 0-10 numerical rating scale just after PIVC. Results - Of the 272 subjects analysed (hypnosis, n=89; nocebo, n=92; neutral, n=91), pain after PIVC was lower in the hypnosis group (mean [standard deviation]; range) (1.5 [1.9]; 0-5) compared with the neutral (3.5 [2.3]; 0-9; P

Resume Les processus hypnotiques modifient la facon d’etre conscient au monde. Ils sont inities par la focalisation de l’attention qui permet de rendre le sujet sensible aux suggestions qui lui sont faites. L’observation ou l’obtention d’un tel etat permet au medecin anesthesiste de delivrer lors des suggestions en rapport avec son objectif de soin. Dans le cadre de l’anesthesie locoregionale, des suggestions de confort, d’analgesie et de facilite peuvent ainsi etre dispensees et aider a la realisation de l’anesthesie. Parallelement, pendant toute la realisation de l’anesthesie, l’hypnose permet de focaliser l’attention du patient sur des elements neutres ou agreables choisis par lui ou le medecin. Tout est rendu plus facile par des techniques simples qui evitent le recours a des medicaments.

International audience; The capacity to monitor suspended sediment concentrations (SSCs) in the ocean, from surface to bottom, using data acquired by the future Meteosat Third-Generation (MTG)/flexible combined imager (FCI) satellite sensor has been quantified by observing system simulation experiments (OSSEs). The ``true'' ocean state for these experiments is based on a 15-month numerical simulation of hydrodynamic and sediment transport, configured to represent the highly dynamical waters of the English Channel under the influences of tides and waves. Simulated MTG/FCI hourly averaged acquisitions at a given location near the Isle of Wight have been processed via hidden Markov model combined with a statistical classification--based on self-organizing maps--of predicted vertical SSC profiles. The resulting experiments demonstrated that MTG/FCI images, despite their high temporal resolution, and because of many gaps due to nights and clouds over the English Channel, still require spatial interpolations to enhance the amount of information available at a given location. For an accurate determination of particle concentrations, time series of the main forcing (wind, tides, and waves) need to be included in the process: 1) as a crucial parameter correlated with the dynamics of large particles (sands) and 2) as an equally important parameter as satellite data themselves in the correlation with the dynamics of fine particles (silts).

Refined assessments of the available tidal stream energy resource are required to optimize turbines design and guarantee successful implementations and operations of devices in the marine environment. Investigations primary focused on identifying areas with maximum current speeds. However, further information may be reached by exhibiting (i) resource temporal variability, (ii) superimposed effects of meteo-oceanographic conditions (including especially wind-generated surface-gravity waves), and (iii) potential environmental impacts of operating turbines at the regional (e.g., changes in sediment transport and surrounding seabed features, effects on marine water quality, etc.) and local (wake-wake interactions and energy output) scales. These aspects are here investigated by reviewing a series of research studies dedicated to the Fromveur Strait off western Brittany, a region with strong potential for tidal array development along the coast of France. Particular attention is dedicated to the exploitation of combined in-situ and remote-sensing observations and numerical simulations. Beyond a site specific characterization of the tidal stream energy resource, this review promotes a series of original approaches and analysis methods for turbines optimization, thus complementing technical specifications to secure the key steps of a tidal energy project and promote the growth of a reliable tidal stream energy exploitation.

Numerical modelling of the flow interactions between tidal turbines in arrays is a prerequisite to assess the energy production potential and to optimise the layout of tidal stream energy farms. It requires (i) a refined representation of the tide propagation and (ii) a reliable estimate of the flow characteristics around the turbines. The Actuator Disk (AD) theory is recognised as a reliable parameterisation to approach the far wake of fixed horizontal-axis turbines and was therefore implemented to provide recommendations as regards to the design of arrays, especially the optimal spacing between devices. However, analysis of the arrangement of tidal stream turbines are typically restricted to schematic test cases with idealised bathymetry and inflow conditions. The present study aims to investigate the flow interactions between turbines in a stream energy site with spatially- and time-varying tidal conditions. The site of application is the Alderney Race (English Channel), an area with strong potential for the exploitation of tidal energy in European shelf seas. The three-dimensional numerical model Telemac3D is used to capture the flow at both the regional and the array scales. Predictions are first assessed against ADCP measurements acquired around the island of Alderney. A series of simulations, representing turbines with the AD theory, are then performed to investigate the influence of the wake interactions on the energy production of individual devices. In those simulations, the turbines are represented with the AD theory. The zone occupied by the turbines is 20D-long and 15D-wide (D is the turbine diameter). Different layouts (isolated, aligned and staggered turbines) and different longitudinal and lateral spacings are considered to investigate the effect of the turbines’ arrangement and density on the array energy production. The results show that, for a given turbines density within the array, the staggered layout produces more than the aligned layout (+16%). When the turbines are staggered, a minimal lateral spacing of 5D is required to avoid wake overlapping. However, when the turbines are aligned, the lateral spacing has a small influence on the turbines production. It is therefore possible to pack the turbines close to each other in the lateral direction. The simulations also outline that the turbulence develops much faster within the array when the turbines are aligned.

This two-center quasiexperimental pilot study was to determine the effect of conversational hypnosis on patient comfort and parasympathetic tone, which may represent a quantitative measure of hypnotic depth, during regional anesthesia. The patients received conversational hypnosis in one center and oral premedication in the other. The patients' subjective comfort (0-10 rating scale) and objective parasympathetic tone, as assessed by the Analgesia/Nociception Index (ANI), were measured before and after regional anesthesia. The parasympathetic tone and comfort scores evidenced a significantly greater increase in the hypnosis patients than in controls. These findings suggest that using conversational hypnosis during regional anesthesia may be followed by a subjective increase in patient comfort and an objective increase in parasympathetic tone, monitored by ANI.

International audience; Coastal waters corresponding to macrotidal systems are among the most variable marine biotopes. Sessile animals as bivalve mollusks may however be found forming intertidal beds at high densities, as allowed by full adaptation to local conditions. A better knowledge of adaptive responses to environmental factors is required to foresee possible adverse effects of global change. At the sub-cellular level, transcriptional responses are among the earliest signals of environmental disturbances and they can reveal subtle and meaningful changes in organism exposed to stress. Three blue mussel (Mytilus spp.) populations inhabiting the Bay of Brest (France) in sites exposed to different levels of chronic pollution, from low to moderate, were surveyed upon a seasonal schedule, with special attention to the reproductive cycle. Major seawater parameters were monitored over a full-year in the framework of the S! RANO project, based on an automatic high frequency acquisition system installed aboard a ship of opportunity. The health status of mussels has been assessed by measuring a condition index and gametogenesis has been followed by histology. Selected biological responses to environmental stress were detected using a multimarker approach including expression of genes involved in chemical stress response and energetic metabolism, and cellular immune parameters. Environmental parameters showed deep seasonal variations which differed among sites. Most biological responses followed a seasonal pattern. Late winter and spring corresponded to an active reproduction period in the Bay of Brest. Earlier spawning was observed in harbor areas compared to the oceanic site and an altered physiological state was assumed in commercial harbor mussels during the reproductive period, suggesting that their health is compromised at this time of year. However, no signs of severe chemical stress were detected in both harbor mussel populations, which could reflect adaptive responses to adverse environmental conditions.

As tidal stream energy sites contribute to a significant part of water transport in coastal shelf seas, turbines’ implementation may lead to system-wide changes of the hydrodynamic circulation with potential effects on marine water quality. These aspects were investigated in north-western coastal waters of Brittany (France, western Europe) by simulating the decay of a tracer concentration within a control domain surrounding the tidal stream energy site of the Fromveur Strait. Simplified simulations were adopted to analyse the sensitivity of tracer distribution to stream energy extraction. While this marine area showed important renewal capacity with a 50 % loss of tracer concentration in less than three days, residual values were still present after two months. This result exhibited that the concentration decay could not be calibrated by simple exponential functions. The renewal of marine waters appeared furthermore dependent on tracer release time during a tidal cycle. A full energy-extraction scenario was finally simulated suggesting weak effects of turbines on the renewal capacity with changes in residence times below 5 % . The spatio-temporal Eulerian evolution of the concentration revealed, however, local trapping areas in close correlation with the Lagrangian residual circulation that vanished after two months.

The purpose of this study was to evaluate the effects of a hypnotically-based intervention for pain and fear in women undergoing labor who are about to receive an epidural catheter. A group of 155 women received interventions that included either (a) patient rocking, gentle touching, and hypnotic communication or (b) patient rocking, gentle touching, and standard communication. The authors found that the hypnotic communication intervention was more effective than the standard communication intervention for reducing both pain intensity and fear. The results support the use of hypnotic communication just before and during epidural placement for women who are in labor and also indicate that additional research to evaluate the benefits and mechanism of this treatment is warranted.

Interest in marine renewable energies has grown in recent years, especially in northern European shelf seas where several technological devices have been developed. In this context, numerous investigations focused on accurate predictions of tidal currents and their respective kinetic energy. An empirical estimation of the current velocity is explored in this study, where three different methods are presented. The first method is a linear approximation of the tidal vector velocity as a function of the tidal coefficient (ratio of the tidal range over its maximal value). The second and the third methods are a piece-wise linear and an exponential relationships between tidal vector velocity and the tidal coefficient, respectively. These three methods are compared to reference values obtained using a numerical simulation of tidal hydrodynamics. These methods are applied at two prominent tidal stream energy sites along the coast of France, the Fromveur Strait (western Brittany) and the Alderney Race (between the island of Alderney, Channel islands, and the Cap de la Hague, France). Results show that the piece-wise linear and the exponential models are more accurate than the linear approximation, where the mean error decreased by 12.7% and 14.9% respectively at the worst case scenario.

The tides are a predictable, renewable, source of energy that, if harnessed, can provide significant levels of electricity generation. The Alderney Race (AR), with current speeds that exceed 5 m s −1 during spring tides, is one of the most concentrated regions of tidal energy in the world, with the upper-bound resource estimated at 5.1 GW. Owing to its significance, the AR is frequently used for model case studies of tidal energy conversion, and here we review these model applications and outcomes. We examine a range of temporal and spatial modelling scales, from regional models applied to resource assessment and characterization, to more detailed models that include energy extraction and array optimization. We also examine a range of physical processes that influence the tidal energy resource, including the role of waves and turbulence in tidal energy resource assessment and loadings on turbines. The review discusses model validation, and covers a range of numerical modelling approaches, from two-dimensional to three-dimensional tidal models, two-way coupled wave-tide models, Large Eddy Simulation (LES) models, and the application of optimization techniques. The review contains guidance on model approaches and sources of data that can be used for future studies of the AR, or translated to other tidal energy regions. This article is part of the theme issue ‘New insights on tidal dynamics and tidal energy harvesting in the Alderney Race’.

Initial selection of tidal stream energy sites is primarily based on identifying areas with the maximum current speeds. However, optimal design and deployment of turbines requires detailed investigations of the temporal variability of the available resource, focusing on areas with reduced variability, and hence the potential for more continuous energy supply. These aspects are investigated here for some of the most promising sites for tidal array development across the north-western European shelf seas: the Alderney Race, the Fromveur Strait, the Pentland Firth and the channels of Orkney. Particular attention was dedicated to asymmetry between the flood and ebb phases of the tidal cycle (due to the phase relationship between M 2 and M 4 constituents), and spring-neap variability of the available resource (due to M 2 and S 2 compound tides). A series of high-resolution models were exploited to (i) produce a detailed harmonic database of these three components, and (ii) characterize, using energy resource metrics, temporal variability of the available power density. There was a clear contrast between the Alderney Race, with reduced temporal variability over semi-diurnal and fortnightly time scales, and sites in western Brittany and North Scotland which, due to increased variability, appeared less attractive for optimal energy conversion. This article is part of the theme issue ‘New insights on tidal dynamics and tidal energy harvesting in the Alderney Race’.

Estimating the energy potential of tidal stream site is a key feature for tidal energy system deployment. This paper aims to compare two methods of prediction of tidal current velocities. The first one is based on the use of a fully three-dimensional (3D) numerical approach. However, while being accurate, the numerical model is highly time-consuming. The second method is based on a linear approximation of the tidal current, which only requires preliminary knowledge of local current velocities time series during two typical tidal cycles. This second method allows a very quick evaluation of the tidal stream resource during a long time period. The proposed comparison is done in three different locations of a high potential tidal energy site in west of France. It is carried out in terms of current velocity and energy harnessing for several turbines technology options (with and without yaw). The achieved results show that the linear approximation gives satisfactory evaluation of the tidal stream potential and can be a very interesting tool for preliminary site evaluation and first technology options selection. However, the fully 3D numerical model can obviously be very useful in more advanced steps of a project.

International audience; Characterising circulation pathways in tidal stream energy sites is fundamental to evaluate the effects of turbines power extraction on long-term water-mass transport. The Lagrangian residual currents are commonly used to assess the displacement of water particles over the tidal period. The associated circulation is, however, characterised by a strong dispersion as water particles may follow different trajectories depending on the release time during a tidal cycle. In order to obtain a synthetic cartography of the Lagrangian circulation, Salomon et al. (1988) proposed an original method that allocates the residual currents at the barycentre of particle trajectories. This Lagrangian barycentric method was here applied to the Fromveur Strait (western Brittany) – a region with strong potential for turbine farm implementation along the coast of France. A high-resolution depth-averaged numerical model computed the tidal circulation driven by the principal lunar semi-diurnal constituent M2. The initial particle positions were taken at the 14,026 nodes of the unstructured computational grid surrounding the area of interest with a spatial resolution below 50 m. In the strait, the residual Lagrangian circulation was characterised by a strong asymmetry between (i) a prominent north-eastern pathway with residual currents up to 0.45 ms-1 and (ii) a southward circulation. Both upstream and downstream the strait, we exhibited prominent cyclonic and anti-cyclonic recirculations. A close correlation was found between the north eddy and a prominent sand bank. We simulated the forces induced by a series of horizontal-axis turbines as an additional bed friction sink term at the scale of the tidal farm. The extraction of tidal stream energy modified the amplitude and direction of the Lagrangian circulation along the current stream emerging from the strait with (i) a tendency for surrounding eddies to get closer to the tidal stream energy site and (ii) possible effects on the evolutionof surrounding seabed features.

Although tidal stream energy is highly predictable, the distribution of the resource varies over small spatial scales and over tidal-to-decadal time scales, requiring detailed models and accurate analysis techniques. The present study investigates the spatial and temporal variability of the tidal stream energy resource around France, using a tidal current harmonic database. The 250 m resolution tidal database covers western Brittany and the western English Channel, two regions that have strong potential for tidal array development. As well as generating a refined resource assessment for the region, a series of metrics are considered to assess resource variability, both spatially and temporally. Particular attention is dedicated to variability over spring-neap time scales (resulting from M 2 and S 2 compound tides) and current asymmetry (governed by M 2 and M 4 velocities). A clear contrast in the nature of the resource is found between sites located off the Cotentin Peninsula, which exhibit low spring-neap variability and tidal asymmetry, leading to a more continuous and therefore attractive energy conversion, and sites in western Brittany, with greater variabilities over semi-diurnal and fortnightly time scales.

An unstructured version of SWAN (Simulating WAves Nearshore) is implemented in the Sea of Iroise (western Europe) to assess the wave energy resource at high spatial resolutions in coastal areas. Numerical results are compared with available measurements of the significant wave height and the peak period at nine locations including (1) long-term offshore observations and (2) medium to short-term data acquired during field campaigns. A medium-term evaluation of the wave energy resource for a eight-years period (2004–2011) is performed exhibiting major nearshore energetic patterns off the isles of Ushant and Sein and in the coastal areas of the bay of Audierne, the Crozon Peninsula and the northern coastline. The variability of wave power production is estimated revealing in accordance with numerical modelling conducted over the European shelf seas significant inter-seasonal and inter-annual evolutions of the resource in the Sea of Iroise. These changes appear particularly noticeable during the winter period with opposite situations in the distribution of monthly average wave energy flux. In the perspective of the implementation of wave energy converters devices, the present assessment is finally exploited to investigate the local distributions of wave energy flux against periods and directions in areas of maximum mean wave power.

International audience; Locations of wave energy converters (WECs) are, most of the time, determined in areas with the highest density of mean wave power while ignoring the temporal variabilities of the resource. The most energetic regions are, however, characterised by strong inter- and intra-annual variations of wave power that may impact the energy production and performances of devices. We investigated these influences by focusing on the generated power from three well-known WECs that reached the stage of full-stage testing: Pelamis, AquaBuOY and Wave Dragon. This evaluation was conducted in western Brittany, one of the most energetic area along the coast of France. In comparison with the available resource, the generated technical power was characterised by reduced annual and seasonal variations. These effects were particularly noticeable for Pelamis that exhibited a reduced intermittency in the energy output between the winter and summer periods. The most energetic conditions had furthermore a restricted contribution to devices power output, mainly related to events with energy periods between 10.5 and 12.5 s, and significant wave heights between 2.75 and 4.25 m. WECs performances exhibited finally strong variabilities, in winter, with monthly-averaged values of the capacity factor up to 65% for Wave Dragon.

Hydro-sedimentary numerical models have been widely employed to derive suspended particulate matter (SPM) concentrations in coastal and estuarine waters. These hydro-sedimentary models are computationally and technically expensive in nature. Here we have used a computationally less-expensive, well-established methodology of self-organizing maps (SOMs) along with a hidden Markov model (HMM) to derive profiles of suspended particulate inorganic matter (SPIM). The concept of the proposed work is to benefit from all available data sets through the use of fusion methods and machine learning approaches that are able to process a growing amount of available data. This approach is applied to two different data sets entitled “Hidden” and “Observable”. The hidden data are composed of 15 months (27 September 2007 to 30 December 2008) of hourly SPIM profiles extracted from the Regional Ocean Modeling System (ROMS). The observable data include forcing parameter variables such as significant wave heights ( H s and H s 50 (50 days)) from the Wavewatch 3-HOMERE database and barotropic currents ( U b a r and V b a r ) from the Iberian–Biscay–Irish (IBI) reanalysis data. These observable data integrate hourly surface samples from 1 February 2002 to 31 December 2012. The time-series profiles of the SPIM have been derived from four different stations in the English Channel by considering 15 months of output hidden data from the ROMS as a statistical representation of the ocean for ≈11 years. The derived SPIM profiles clearly show seasonal and tidal fluctuations in accordance with the parent numerical model output. The surface SPIM concentrations of the derived model have been validated with satellite remote sensing data. The time series of the modeled SPIM and satellite-derived SPIM show similar seasonal fluctuations. The ranges of concentrations for the four stations are also in good agreement with the corresponding satellite data. The high accuracy of the estimated 25 h average surface SPIM concentrations (normalized root-mean-square error— N R M S E of less than 16%) is the first step in demonstrating the robustness of the method.

International audience; Whereas tidal stream energy sites may be characterised by significant wave and current interactions, numerical resource assessments routinely ignored these processes neglecting, in particular, current-induced modifications of waves. Here, these effects are investigated in locations exposed to ocean waves, evaluating performances of a phase-averaged numerical wave model to approach observed semi-diurnal modulations of wave heights, periods and directions, off and within the Fromveur Strait (western Brittany), a region with strong potential for tidal array development. The introduction of tidal forcings in the wave model is found to improve predictions by approaching the large-scale influence of current-induced refraction leading to variations of the significant wave height by nearly 30 % at the deep-water wave buoy. The model reproduces furthermore, with the inclusion of an additional dissipation term, the localised steepening and waves breaking on negative current gradients, limiting the overestimation of the significant wave height at the shallow-water wave buoy within the Fromveur Strait. Tidal currents may finally lead to a strong increase in wave power, over 100 % in northern entrances of straits, contributing to the variability of the wave energy flux.

Hypnosis has shown an effect on the regulation of the autonomic nervous system by increasing parasympathetic activity. The Analgesia/Nociception Index (ANI) is derived from heart rate variability and represents the relative parasympathetic tone. We investigated the effects of hypnosis on ANI in healthy volunteers. Participants to the 2016 International Hypnosis congress, Saint Malo, France were recruited in this prospective observational study. After comfortable positioning of the subject in the sitting position (T0), the hypnotic trance was induced (T1) then conducted with suggestions of comfort (T2) before return to normal consciousness (T3). The ANI, heart rate (HR) and respiratory rate (RR) were recorded at the different time-points. Forty subjects were enrolled (31 women, 9 men). The mean ± SD ANI at T2 (84 ± 12) was significantly greater than at T0 (60 ± 10), T1 (62 ± 9) and T3 (59 ± 11). The median [25th–75th percentile] ANI values at T2 were significantly greater in women (90 [83–95]) than in men (74 [68–83]). There were no significant variations of HR during time. The median [25th–75th percentile] RR at T1 (16 [14–18] breaths/min) and T2 (14 [12–16] breaths/min) were significantly smaller than at T0 (18 [16–20] breaths/min) and T3 (18 [16–20] breaths/min). This study shows that hypnosis induces an increase in the relative parasympathetic tone assessed by ANI in healthy volunteers, with greater ANI values observed in women. These results suggest that ANI monitoring may provide an objective tool for the measurement of the intensity of the hypnotic process, although this should be confirmed by further studies.

International audience; One of the biggest uncertainties in tidal stream energy resource assessment is how tidal energy conversion, particularly at large scale, will interact with the resource. As few arrays are currently operational, data collected from these developments tends to be commercially sensitive. Therefore, array interaction with the resource is generally assessed using numerical models. A fully three-dimensional numerical approach based on Actuator Disk theory was implemented into the Regional Ocean Modelling System (ROMS) to simulate the energy extraction by tidal stream turbines. Emphasis was placed on wake interactions and cumulative effects of individual devices on energy extraction at array scale. This model was applied at the tidal stream energy site of the Fromveur Strait (western Brittany, France) considering an array of horizontal-axis turbines of 10-m diameter, matching the device technology currently operating in the Strait. Two tidal energy metrics were considered to describe asymmetries in tidal current magnitude and direction. The area with reduced asymmetry in current magnitude was selected to implement the turbine array. A nested grid technique was adopted to cascade processes from the regional scale to the high-resolution local farm domain. The computation was conducted over the inner-nested array domain covering the tidal farm with horizontal and vertical resolutions of 1 m, matching the 1/10th turbine diameter (D) recommended to resolve velocity and turbulence intensity along device wakes. The array layout initially followed recommended staggered configurations with longitudinal and lateral spacings of 10D and 5D, respectively. However, during mean spring tidal conditions, the misalignment of peak flood currents induced significant wake interactions that reduced the array output by about 15% in comparison to peak ebb. These interactions were investigated to adapt array layouts, minimise wake interactions, and optimise the energy conversion. By reducing the lateral spacing between devices to 3D (measured centre to centre rather than tip to tip), the flood ebb asymmetry in energy extraction was lowered from 15% to 2%.

Essentially brought by the Aulne and Elorn rivers, fine sediments are redistributed within the bay of Brest and its surroundings mainly by tidal currents. Their dynamic is studied with a hydro-sedimentary numerical model based on the two-dimensional horizontal (2DH) modules of the TELEMAC system. The sedimentary assemblage is treated as a number of components of different grain sizes, some of which may be cohesive, and biotic factors related to the large presence on the bed of the invading slipper limpets Crepidula fornicata are integrated. A special approach consisting in solving the advection-diffusion equation with multi-zone marked fine sediments to evaluate their relative contribution to suspended and deposited sediment concentration is presented herein. This Eulerian sediment tracing method is promising for evaluating exchanges between sedimentary units according to hydraulic (low flow, flood) and hydrodynamic (neap, spring) conditions under various scenarios.

Disamina degli elementi costitutivi di un nuovo crimine internazionale di ecocidio

International audience; Whereas numerous numerical modelling have been conducted to gain further insights about the hydrodynamic characteristics of tidal stream energy sites, the long-term transport of water particles has been routinely ignored. However, a refined evaluation of circulation pathways is fundamental to assess water-quality changes induced by tidal energy converters. The present study investigates the tide-induced Lagrangian circulation in northwestern coastal waters of Brittany (France, western Europe), including numerous islands, shoals and straits with strong potential for turbine farm implementation. Particular attention is dedicated to the hydrodynamic impact of tidal stream power extraction from a series of horizontal-axis turbines. An original approach, based on the coupling of the Lagrangian barycentric method with predictions from a model with high spatial resolution, is considered to assess circulation pathways in a single synoptic view. Spatial results reveal a complex Lagrangian circulation highly controlled by bathymetry and islands geometry. The residual flow in the Fromveur Strait, separating Ushant island fromMoì ene archipelago, displays thus a strong asymmetry, between a prominent northeastern pathway with residual currents up to 0.45 m s −1 and a southward circulation. The positions of cyclonic and anti-cyclonic recirculations, both upstream and downstream the Strait, are furthermore precisely defined. The north eddy is found closely located to the sand bank of the Four. The extraction of tidal stream power impacts mainly the residual Lagrangian circulation along the current stream emerging from the Strait, with a tendency for surrounding eddies to get closer to the tidal stream energy site. The displacements of the south and north recirculations may thus exceed 1.5 km with possible implications on the evolution of surrounding seabed features.

National audience; This study analyses the sensitivity of a tidal hydrodynamic model to the parameterisation of rock bottom roughess in the Fromveur Strait off western Brittany. The attention is dedicated to estimations of currents, associated kinetic energy and bottom shear stress without and with a tidal stream farm. The available predicted tidal stream power shows variations up to 30 % in relation to the bottom roughness retained. Tidal stream power extraction with a tidal farm induces noticeable reductions of tidal currents and bottom shear stresses up to 10 km from the Strait. Bottom roughness impacts the amplitude of this reduction with variations of shear stresses from 9 to 17 % over the sandbank of the Four.; Cette étude analyse la sensibilité d'un modèle hydrodynamique de marée a la paramétrisation de la rugosité des fonds rocheux au niveau du Passage du Fromveur en pointe Bretagne. L'attention est portée sur les estimations des courants, de la puissance associée et de la contrainte de cisaillement de fond sans et avec la présence d'un parc hydrolien. Les prédictions de la puissance du courant disponible présentent des variations allant jusqu'à 30 % en fonction de la rugosité de fond retenue. L'extraction de cette puissance par un parc hydrolien induit une réduction substantielle des courants de marée et de la contrainte de cisaillement de fond associée à plus de 10 km du Passage du Fromveur. La rugosité de fond influe sur l'amplitude de cette réduction avec des variations de la contrainte de cisaillement comprises entre 9 et 17 % au niveau du banc sableux du Four.

International audience

Successful deployment of tidal energy converters relies on access to accurate and high resolution numerical assessments of available tidal stream power. However, since suitable tidal stream sites are located in relatively shallow waters of the continental shelf where tidal currents are enhanced, tidal energy converters may experience effects of wind-generated surface-gravity waves. Waves may thus influence tidal currents, and associated kinetic energy, through two non-linear processes: the interaction of wave and current bottom boundary layers, and the generation of wave-induced currents. Here, we develop a three-dimensional tidal circulation model coupled with a phase-averaged wave model to quantify the impact of the waves on the tidal kinetic energy resource of the Fromveur Strait (western Brittany) - a region that has been identified with strong potential for tidal array development. Numerical results are compared with in situ observations of wave parameters (significant wave height, peak period and mean wave direction) and current amplitude and direction 10 m above the seabed (the assumed technology hub height for this region). The introduction of waves is found to improve predictions of tidal stream power at 10 m above the seabed at the measurement site in the Strait, reducing kinetic energy by up to 9% during storm conditions. Synoptic effects of wave radiation stresses and enhanced bottom friction are more specifically identified at the scale of the Strait. Waves contribute to a slight increase in the spatial gradient of available mean tidal stream potential between the north-western area and the south-eastern part of the Strait. At the scale of the region within the Strait that has been identified for tidal stream array development, the available mean spring tidal stream potential is furthermore reduced by 12% during extreme waves conditions. Isolated effects of wave radiation stresses and enhanced bottom friction lead to a reduction in spring tidal potential of 7.8% and 5.3%, respectively. It is therefore suggested that models used for tidal resource assessment consider the effect of waves in appropriately wave-exposed regions.