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Mesoscale warm‐core rings, known as Loop Current rings (LCRs) reshape the Gulf of Mexico water masses by redistributing large amounts of heat and salt laterally. LCRs also transform water masses via diapycnal mixing, but the mechanisms by which this occurs are poorly measured. Here, we present glider‐MicroPod turbulence observations that reveal enhanced mixing below the mixed layer, along the eddy edges, driving the LCR's heat, salt, and oxygen exchanges. Interleavings of adjacent water masses may be interpreted mainly as a manifestation of submesoscale processes through stirring of the spice gradients, which facilitates double‐diffusive mixing that transforms Subtropical Underwater into Gulf Common Water. Our findings highlight the need for ocean models to parameterize double‐diffusive mixing processes directly resulting from submesoscale tracer stirring, which may be important at basin scale in the presence of LCRs in the Gulf of Mexico. Plain Language Summary In the Gulf of Mexico (GoM), anticyclonic eddies, known as Loop Current rings (LCRs) carrying warm and salty water shape the basin's water mass properties, which in turn, affects the regional climate and marine life. The water mass properties are altered by turbulent mixing. However, the mechanisms leading to the mixing of GoM waters are still under debate due to a lack of observations. Here, we use an autonomous underwater vehicle (glider) equipped with a turbulence sensor to assess the nature of LCR mixing and its impact on water properties. The breaking of internal waves in the ocean is often thought to be responsible for turbulent mixing in the ocean interior. However, our findings demonstrate that a process called double‐diffusive convection is responsible, where turbulence is forced by differences between the temperature and salinity of adjacent water parcels. We found that double‐diffusive convection was the main driver in mixing heat, salt, and oxygen along the eddy edges, producing Gulf Common Water. These findings highlight the need to include double diffusive processes in ocean models for more accurate simulations. Key Points Direct observations of turbulence reveal the distribution of mixing across a Gulf of Mexico Loop Current Ring Subtropical Underwater is transformed into Gulf Common Water through double‐diffusive convection on the edges of the eddy

The recent integration of Acoustic Doppler Current Profilers (ADCPs) onto underwater gliders changes the way current and sediment dynamics in the coastal zone can be monitored. Their endurance and ability to measure in all weather conditions increases the probability of capturing sporadic meteorological events, such as storms and floods, which are key elements of sediment dynamics. We used a Slocum glider equipped with a CTD (Conductivity, Temperature, Depth), an optical payload, and an RDI 600 kHz phased array ADCP. Two deployments were carried out during two contrasting periods of the year in the Rhone River region of freshwater influence (ROFI). Coastal absolute currents were reconstructed using the shear method and bottom tracking measurements, and generally appear to be in geostrophic balance. The responses of the acoustic backscatter index and optical turbidity signals appear to be linked to changes of the particle size distribution in the water column. Significantly, this study shows the interest of using a glider-ADCP for coastal zone monitoring. However, the comparison between suspended particulate matter dynamics from satellites and gliders also suggests that a synoptic view of the processes involved requires a multiplatform approach, especially in systems with high spatial and temporal variability, such as the Rhone ROFI area.

Underwater gliders equipped with current profilers and optical turbidity sensors offer a low-energy solution for high-resolution measurements of currents, suspended particle properties, and sediment transport in coastal waters. Because the spatial structure of hydrosedimentary processes often changes on short time scales (hours to weeks), especially in coastal areas, validating the distribution of glider observations is required to assess our capacity to represent hydrosedimentary processes. Here we propose to validate in a shelf tide-dominated environment, both (i) glider-based currents, and (ii) glider-based acoustic backscatters and optical turbidities in full resolution delayed mode, using in situ collocated and synchronous ancillary observations. The deployed glider system correctly measures the periodic pattern of the tidal current, with a RMSD of O(3 cm s−1), demonstrating the system's ability to accurately capture tidal variability. Glider optical turbidities highly correlate with the ancillary observations (R2 up to 0.83). They also correlate well with their glider acoustic counterpart for most of the campaign period (R2=0.76), allowing an estimation of suspended particulate matter concentrations from acoustic measurements. Hence, the glider could observe not only the presence of bottom nepheloid layers of several mg L−1 but also residual fluxes of the order of 1 gm-1s-1 on the shelf. These results highlight the potential of gliders for quantifying sediment fluxes and advancing our understanding of coastal hydrosedimentary processes.

Background With the lack of effective therapy, chemoprevention, and vaccination against SARS-CoV-2, focusing on the immediate repurposing of existing drugs gives hope of curbing the COVID-19 pandemic. A recent unbiased genomics-guided tracing of the SARS-CoV-2 targets in human cells identified vitamin D among the three top-scoring molecules manifesting potential infection mitigation patterns. Growing pre-clinical and epidemiological observational data support this assumption. We hypothesized that vitamin D supplementation may improve the prognosis of COVID-19. The aim of this trial is to compare the effect of a single oral high dose of cholecalciferol versus a single oral standard dose on all-cause 14-day mortality rate in COVID-19 older adults at higher risk of worsening. Methods The COVIT-TRIAL study is an open-label, multicenter, randomized controlled superiority trial. Patients aged ≥ 65 years with COVID-19 (diagnosed within the preceding 3 days with RT-PCR and/or chest CT scan) and at least one worsening risk factor at the time of inclusion (i.e., age ≥ 75 years, or SpO2 ≤ 94% in room air, or PaO2/FiO2 ≤ 300 mmHg), having no contraindications to vitamin D supplementation, and having received no vitamin D supplementation > 800 IU/day during the preceding month are recruited. Participants are randomized either to high-dose cholecalciferol (two 200,000 IU drinking vials at once on the day of inclusion) or to standard-dose cholecalciferol (one 50,000 IU drinking vial on the day of inclusion). Two hundred sixty participants are recruited and followed up for 28 days. The primary outcome measure is all-cause mortality within 14 days of inclusion. Secondary outcomes are the score changes on the World Health Organization Ordinal Scale for Clinical Improvement (OSCI) scale for COVID-19, and the between-group comparison of safety. These outcomes are assessed at baseline, day 14, and day 28, together with the serum concentrations of 25(OH)D, creatinine, calcium, and albumin at baseline and day 7. Discussion COVIT-TRIAL is to our knowledge the first randomized controlled trial testing the effect of vitamin D supplementation on the prognosis of COVID-19 in high-risk older patients. High-dose vitamin D supplementation may be an effective, well-tolerated, and easily and immediately accessible treatment for COVID-19, the incidence of which increases dramatically and for which there are currently no scientifically validated treatments. Trial registration ClinicalTrials.gov NCT04344041 . Registered on 14 April 2020 Trial status Recruiting. Recruitment is expected to be completed in April 2021.

Les organisations à haute fiabilité sont désormais soumises à des contraintes économiques et industrielles qu’elles doivent concilier avec les impératifs de sûreté et de sécurité. Plus que jamais, la question de la bonne articulation entre un haut niveau de prescription et un flux permanent d’aléas est au cœur des préoccupations de ces organisations. Cela se traduit par une attention constante portée aux activités opérationnelles. Cet article s’appuie sur une recherche-intervention conduite depuis 2013 au sein d’une usine industrielle à risques confrontée à des problèmes de tenue des délais de ses projets d’arrêt pour maintenance et à des tensions en matière de qualité de vie au travail. Le caractère remarquable du cas analysé réside dans le fait qu’en dépit d’une culture de la sécurité très attentive à la coordination opérationnelle, l’organisation peine à penser les espaces qui permettraient un véritable dialogue sur l’activité. Nous montrons, dès lors, qu’il ne suffit pas de multiplier les dispositifs de coordination pour construire la performance globale d’une organisation. En effet, la sur-instrumentation de la communication peut, au contraire, devenir contreproductive, lorsque le travail reste silencieux alors que la communication devient de plus en plus cacophonique. Dans la lignée des travaux de Detchessahar (2013), l’article dessine une ingénierie des espaces de discussion du travail qui soit à même de prendre en charge les multiples tensions qui traversent les organisations à haute fiabilité (HRO – High Reliability Organizations ). Between noise and silence, engineering a dialog about work: Maintenance projects in a high-risk industryHigh reliability organizations are now subject to economic and industrial constraints that they have to dovetail with the imperatives of safety and security. They have to pay constant attention to their operational activities. More than ever, their key preoccupation is the question of the right combination between a high level of prescriptions and an ongoing series of contingencies. This intervention research has been conducted since 2013 in a high-risk industrial plant with problems of keeping the deadlines set for maintenance work and with tensions related to the quality of life at the workplace. What is remarkable about this case is that, despite a “culture of security” very attentive to coordinating operations, the organization has difficulty imagining how to design the conditions for a genuine dialog on workplace activities. To improve an organization’s overall performance, it does not suffice to set up ever more arrangements for coordination. On the contrary, an overinstrumentation of communications can become counterproductive as work remains silent while communications make ever more noise. How to engineer opportunities for discussing work so as to address the many tensions running through high-reliability organizations ?

Les organisations à haute fiabilité sont désormais soumises à des contraintes économiques et industrielles qu'elles doivent concilier avec les impératifs de sûreté et de sécurité. Plus que jamais, la question de la bonne articulation entre un haut niveau de prescription et un flux permanent d'aléas est au cœur des préoccupations de ces organisations. Cela se traduit par une attention constante portée aux activités opérationnelles. Cet article s'appuie sur une recherche-intervention conduite depuis 2013 au sein d'une usine industrielle à risques confrontée à des problèmes de tenue des délais de ses projets d'arrêt pour maintenance et à des tensions en matière de qualité de vie au travail. Le caractère remarquable du cas analysé réside dans le fait qu'en dépit d'une culture de la sécurité très attentive à la coordination opérationnelle, l'organisation peine à penser les espaces qui permettraient un véritable dialogue sur l'activité. Les auteurs montrent, dès lors, qu'il ne suffit pas de multiplier les dispositifs de coordination pour construire la performance globale d'une organisation. En effet, la sur-instrumentation de la communication peut, au contraire, devenir contre-productive, lorsque le travail reste silencieux alors que la communication devient de plus en plus cacophonique. Dans la lignée des travaux de Detchessahar (2013), l'article dessine une ingénierie des espaces de discussion du travail qui soit à même de prendre en charge les multiples tensions qui traversent les organisations à haute fiabilité (HRO - High Reliability Organizations). Document de fond. Pas de chiffres.