9 research outputs found

    Mixed properties of magnetohydrodynamic waves undergoing resonant absorption in the cusp continuum

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    Observations of magnetohydrodynamic (MHD) waves in the structured solar atmosphere have shown that these waves are damped and can thus contribute to atmospheric heating. In this paper, we focus on the damping mechanism of resonant absorption in the cusp continuum. This process takes places when waves travel through an inhomogeneous plasma. Our aim is to determine the properties of MHD waves undergoing resonant absorption in the cusp continuum in the transition layer of a cylindrical solar atmospheric structure, such as a photospheric pore or a coronal loop. Depending on which quantities dominate, one can assess what type of classical MHD wave the modes in question resemble most. In order to study the properties of these waves, we analytically determine the spatial profiles of compression, displacement, and vorticity for waves with frequencies in the cusp continuum, which undergo resonant absorption. We confirm these analytical derivations via numerical calculations of the profiles in the resistive MHD framework. We show that the dominant quantities for the modes in the cusp continuum are the displacement parallel to the background magnetic field and the vorticity component in the azimuthal direction (i.e. perpendicular to the background magnetic field and along the loop boundary)

    Utilization of mechanical power and associations with clinical outcomes in brain injured patients: a secondary analysis of the extubation strategies in neuro-intensive care unit patients and associations with outcome (ENIO) trial

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    Background: There is insufficient evidence to guide ventilatory targets in acute brain injury (ABI). Recent studies have shown associations between mechanical power (MP) and mortality in critical care populations. We aimed to describe MP in ventilated patients with ABI, and evaluate associations between MP and clinical outcomes. Methods: In this preplanned, secondary analysis of a prospective, multi-center, observational cohort study (ENIO, NCT03400904), we included adult patients with ABI (Glasgow Coma Scale ≤ 12 before intubation) who required mechanical ventilation (MV) ≥ 24 h. Using multivariable log binomial regressions, we separately assessed associations between MP on hospital day (HD)1, HD3, HD7 and clinical outcomes: hospital mortality, need for reintubation, tracheostomy placement, and development of acute respiratory distress syndrome (ARDS). Results: We included 1217 patients (mean age 51.2 years [SD 18.1], 66% male, mean body mass index [BMI] 26.3 [SD 5.18]) hospitalized at 62 intensive care units in 18 countries. Hospital mortality was 11% (n = 139), 44% (n = 536) were extubated by HD7 of which 20% (107/536) required reintubation, 28% (n = 340) underwent tracheostomy placement, and 9% (n = 114) developed ARDS. The median MP on HD1, HD3, and HD7 was 11.9 J/min [IQR 9.2-15.1], 13 J/min [IQR 10-17], and 14 J/min [IQR 11-20], respectively. MP was overall higher in patients with ARDS, especially those with higher ARDS severity. After controlling for same-day pressure of arterial oxygen/fraction of inspired oxygen (P/F ratio), BMI, and neurological severity, MP at HD1, HD3, and HD7 was independently associated with hospital mortality, reintubation and tracheostomy placement. The adjusted relative risk (aRR) was greater at higher MP, and strongest for: mortality on HD1 (compared to the HD1 median MP 11.9 J/min, aRR at 17 J/min was 1.22, 95% CI 1.14-1.30) and HD3 (1.38, 95% CI 1.23-1.53), reintubation on HD1 (1.64; 95% CI 1.57-1.72), and tracheostomy on HD7 (1.53; 95%CI 1.18-1.99). MP was associated with the development of moderate-severe ARDS on HD1 (2.07; 95% CI 1.56-2.78) and HD3 (1.76; 95% CI 1.41-2.22). Conclusions: Exposure to high MP during the first week of MV is associated with poor clinical outcomes in ABI, independent of P/F ratio and neurological severity. Potential benefits of optimizing ventilator settings to limit MP warrant further investigation

    Mobility of individual roach Rutilus rutilus (L.) in three weir-fragmented Belgian rivers

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    Adult roach Rutilus rutilus (L.) (N = 24; 19.9-36.1 cm FL) from three highly fragmented Belgian rivers were tagged with surgically implanted radio transmitters. Their seasonal movements were observed from March to August 2004 (circum reproduction period) in river stretches delimited by two physical barriers. In the three rivers, roach displayed similar patterns of movements which were mainly influenced by the date of observation (movements increased in late April-May) and water temperature (travel distances were more important when water temperature ranged between 10 degrees C and 14 degrees C). Roach sometimes cleared physical obstacles. The mean distances travelled in each river were relatively short (max. 2.5 km) and mainly influenced by the length of the study reach, which was delimited by physical barriers

    A 4-years eel research proposal submitted to the Belgian research Programme "Science for a sustainable development

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    The European eel (Anguilla anguilla (L).) is a widespread species in decline and current fisheries are considered outside sustainable limits. The European Commission has proposed that the primary instrument for management of European eel should be the development by Member States of "Eel Management Plans" including putting in place monitoring actions for the EU Data Collection Regulation. A research project proposal has been submitted to the Belgian Research programme “Science for a Sustainable Development”. Partners involved are institutes and universities in Flanders and Wallonia. The project is entitled “Progressive extinction of the eel: biological basis for a national recovery plan” and has the acronym ”EELBASE”. The objective is setting the scientific base for the development of the national Eel Management Plans by developing an eel database (EELBASE), designing a Belgian eel restocking programme and collecting new data about the key factors affecting the eel stocks throughout Belgium. Field studies in selected basins will focus on ecological aspects including habitat evaluation of yellow eel, silver eel escapement and impact of turbines and pumps. Another objective is to evaluate interactions between the different environmental and physiological parameters by means of an extensive assessment of physiological traits of eels of polluted and unpolluted sites. For this, several aspects of health and condition of local pre-silver and silver eel populations will be studied (a series of physiological parameters, quality of gametes, parasitological and viral agents, …).Keywords: European eel, Anguilla anguilla, management, stocks, migration, physiolog

    Impact assessment and remediation of anthropogenic interventions on fish populations - (FISHGUARD)

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    The disruption of longitudinal river connectivity by man-made obstacles and the stocking of fish communities with non-indigenous species or genotypes threaten the fish fauna of Belgian rivers to various extents. Obstacles impede migrations between habitats that are vital for populations, and they may restrict the gene flow between populations, thereby reducing the effective size and genetic diversity of populations and increasing the risk of local extinction. Restocking programs often involve the introduction of non-indigenous genotypes in native populations. Moreover, although stocking programs lead to the temporal and superficial enrichment of local fish communities or gene pools, they generally result in a loss of biodiversity on a regional or international scale through the homogenisation of communities and the breakdown of genetic differentiation between populations. Thus, stocking programs cannot compensate for the loss of free migration by artificial obstructions. The impact of these changes on fish populations remains largely unknown, which complicates the priorisation of spots to preserve and spots to restore. Here, we present an integrated study on Belgian waters, both in Flanders and Wallonia, which analyses fish communities, gene flow and migration patterns in the field, as well as the swimming and leaping performances of fishes under controlled conditions.Global change, Ecosystems and Biodiversit

    Outcomes in 886 Critically Ill Patients After Near-Hanging Injury

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    International audienceBackground: Near-hanging experiences are life-threatening events about which few data are available. Research Question: What are the outcomes and early predictors of hospital mortality in critically ill patients who have undergone a near-hanging experience? Study Design and Methods: Adult patients who were resuscitated successfully after suicidal near-hanging injury admitted to 31 university or university-affiliated ICUs in France and Belgium between 1992 and 2014 were studied retrospectively. Patients were identified by searching the hospital databases for International Statistical Classification of Diseases and Related Health Problems, 9th and 10th revisions, codes and hospital charts for hanging. Logistic multivariate regression was performed to identify factors associated vital and functional outcomes at hospital discharge as the primary end points. Secondary outcomes were evaluation of temporal trends and identification of predictors of hospital mortality. Results: Of the 886 patients (181 women and 705 men; median age, 43 years; interquartile range, 34-52 years), 266 (30.0%) had attempted suicide previously, 600 (67.7%) had a diagnosed mental illness, and 55 (6.2%) attempted hanging while hospitalized. Median time from hanging awareness to unhanging was 0 min (interquartile range [IQR], 0-0; range, 0-82 min). Median Glasgow Coma Scale score was 3 (IQR, 3-5) at ICU admission. Hanging induced cardiac arrest in 450 of 886 patients (50.8%). Overall, 497 of 886 patients (56.1%) were alive at hospital discharge, including 479 of 497 patients (96.4%) with a favorable neurocognitive outcome (defined as a Glasgow Outcome Scale score of 4 or 5). By multivariate analysis, factors associated with hospital mortality were hanging-induced cardiac arrest (OR, 19.50; 95% CI, 7.21-60.90; P 1.4 g/L (OR, 4.34; 95% CI, 1.82-10.81; P = .0007) and of lactate level > 3.5 mmol/L (OR, 9.98; 95% CI, 4.17-25.36; P < .00001). Interpretation: The findings from this large multicenter retrospective cohort emphasize the very high mortality after hanging injury chiefly because of hanging-induced cardiac arrest. However, patients who survive near-hanging experiences achieve excellent neurocognitive recovery. Studies of early neuroprotective strategies for patients who have undergone near-hanging experiences are warranted. Trial Registry: ClinicalTrials.gov; No.: NCT04096976; URL: www.clinicaltrials.go

    Extubation in neurocritical care patients: the ENIO international prospective study

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    Purpose: Neurocritical care patients receive prolonged invasive mechanical ventilation (IMV), but there is poor specific information in this high-risk population about the liberation strategies of invasive mechanical ventilation. Methods: ENIO (NCT03400904) is an international, prospective observational study, in 73 intensive care units (ICUs) in 18 countries from 2018 to 2020. Neurocritical care patients with a Glasgow Coma Score (GCS) ≤ 12, receiving IMV ≥ 24 h, undergoing extubation attempt or tracheostomy were included. The primary endpoint was extubation failure by day 5. An extubation success prediction score was created, with 2/3 of patients randomly allocated to the training cohort and 1/3 to the validation cohort. Secondary endpoints were the duration of IMV and in-ICU mortality. Results: 1512 patients were included. Among the 1193 (78.9%) patients who underwent an extubation attempt, 231 (19.4%) failures were recorded. The score for successful extubation prediction retained 20 variables as independent predictors. The area under the curve (AUC) in the training cohort was 0.79 95% confidence interval (CI95) [0.71-0.87] and 0.71 CI95 [0.61-0.81] in the validation cohort. Patients with extubation failure displayed a longer IMV duration (14 [7-21] vs 6 [3-11] days) and a higher in-ICU mortality rate (8.7% vs 2.4%). Three hundred and nineteen (21.1%) patients underwent tracheostomy without extubation attempt. Patients with direct tracheostomy displayed a longer duration of IMV and higher in-ICU mortality than patients with an extubation attempt (success and failure). Conclusions: In neurocritical care patients, extubation failure is high and is associated with unfavourable outcomes. A score could predict extubation success in multiple settings. However, it will be mandatory to validate our findings in another prospective independent cohort
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