Abstract
The disintegration of the ice shelves along the Antarctic Peninsula have spurred much discussion on the various processes leading to their eventual dramatic collapse, but without a consensus ...on an atmospheric forcing that could connect these processes. Here, using an atmospheric river detection algorithm along with a regional climate model and satellite observations, we show that the most intense atmospheric rivers induce extremes in temperature, surface melt, sea-ice disintegration, or large swells that destabilize the ice shelves with 40% probability. This was observed during the collapses of the Larsen A and B ice shelves during the summers of 1995 and 2002 respectively. Overall, 60% of calving events from 2000–2020 were triggered by atmospheric rivers. The loss of the buttressing effect from these ice shelves leads to further continental ice loss and subsequent sea-level rise. Under future warming projections, the Larsen C ice shelf will be at-risk from the same processes.
In a context of global warming and sea level rise acceleration, it is key to estimate the evolution of the atmospheric hydrological cycle and temperature in polar regions, which directly influence ...the surface mass balance of the Arctic and Antarctic ice sheets. Direct observations are available from satellite data for the last 40 years and a few weather data since the 1950s in Antarctica. One of the best ways to access longer records is to use climate proxies in firn or ice cores. The water isotopic composition in these cores is widely used to reconstruct past temperature variations.
Glanzmann thrombasthenia (GT) is a genetic bleeding disorder characterised by severely reduced/absent platelet aggregation in response to multiple physiological agonists. The severity of bleeding in ...GT varies markedly, as does the emergency situations and complications encountered in patients. A number of emergency situations may occur in the context of GT, including spontaneous or provoked bleeding, such as surgery or childbirth. While general management principles apply in each of these settings, specific considerations are essential for the management of GT to avoid escalating minor bleeding events. These recommendations have been developed from a literature review and consensus from experts of the French Network for Inherited Platelet Disorders, the French Society of Emergency Medicine, representatives of patients' associations, and Orphanet to aid decision making and optimise clinical care by non-GT expert health professionals who encounter emergency situations in patients with GT.
During atmospheric river (AR) landfalls on the Antarctic ice sheet, the high waviness of the circumpolar polar jet stream allows for subtropical air masses to be advected toward the Antarctic ...coastline. These rare but high‐impact AR events are highly consequential for the Antarctic mass balance; yet little is known about the various atmospheric dynamical components determining their life cycle. By using an AR detection algorithm to retrieve AR landfalls at Dumont d'Urville and non‐AR analogs based on 700 hPa geopotential height, we examined what makes AR landfalls unique and studied the complete life cycle of ARs reaching Dumont d'Urville. ARs form in the mid‐latitudes/subtropics in areas of high surface evaporation, likely in response to tropical deep convection anomalies. These convection anomalies likely lead to Rossby wave trains that help amplify the upper‐tropospheric flow pattern. As the AR approaches Antarctica, condensation of isentropically lifted moisture causes latent heat release that—in conjunction with poleward warm air advection—induces geopotential height rises and anticyclonic upper‐level potential vorticity tendencies downstream. As evidenced by a blocking index, these tendencies lead to enhanced ridging/blocking that persist beyond the AR landfall time, sustaining warm air advection onto the ice sheet. Finally, we demonstrate a connection between tropopause polar vortices and mid‐latitude cyclogenesis in an AR case study. Overall, the non‐AR analogs reveal that the amplified jet pattern observed during AR landfalls is a result of enhanced poleward moisture transport and associated diabatic heating which is likely impossible to replicate without strong moisture transport.
Plain Language Summary
When the polar jet stream that surrounds Antarctica is highly wavy, air masses from the subtropics that are warm and humid are often transported over the ice sheet in the form of atmospheric rivers (ARs). When ARs reach Antarctica, they often bring extreme weather conditions that have large consequences for ice sheet snowfall and surface melt. Here we studied the full life cycle of ARs that reached Dumont d'Urville in East Antarctica and compared these ARs against events with similar profiles of atmospheric circulation. ARs typically form in areas of unusually high surface evaporation and thunderstorm convection in the subtropics. This convection sends Rossby waves toward the Antarctic coastline which help make the polar jet wavier. The amplitude of the polar jet is further enhanced when the moisture that accompanies the ARs condenses over the cooler seas around Antarctica and creates large latent heating. The higher amplitude of the polar jet often results in atmospheric blocks that transport further warm, moist air over the ice sheet even after the AR has made landfall and dissipated. Therefore, extreme weather events over Antarctica like ARs are sensitive to climate changes far from the continent over the subtropical regions.
Key Points
Atmospheric rivers have lower‐latitude moisture sources than extratropical cyclones and are likely influenced by tropopause polar vortices
Large latent heat release from atmospheric river related moisture transport leads to downstream anticyclonic potential vorticity tendencies
The resultant diabatic heating helps maintain atmospheric blocking after an atmospheric river has dissipated
Feasibility checking is a step in manufacturing system engineering for verifying the normalization and effectiveness of a manufacturing system associated with a specific configuration of resources ...and processes. It enables factory operators to predict problems before operational time, thus preventing equipment and machinery accidents and reducing labor waste in physically organizing the shop floor. In Industry 4.0, feasibility checking becomes even more critical since emerging challenges, such as mass personalization, require reconfiguring work cells quickly and flexibly on demand. Regarding this need, digital twin technologies have emerged as an ideal candidate for practicing feasibility checking. Indeed, they are tools used to implement digital representations of manufacturing entities that can constitute a digital environment and context. Factory operators can test a manufacturing process within a digital environment in different contexts before the execution with physical resources. This approach currently receives significant attention from the manufacturing community; however, there is still a lack of sharing experiences to implement it. Thus, this paper contributes a methodology to engineer a digital environment and context for a manufacturing work cell using AAS digital twins and physics-based 3D digital twins technologies. Technically, this methodology is a specific case of N-DTs, a general methodology for engineering heterogeneous digital twins. The product assembly line case study, also presented in this paper, is a successful experiment applying the above contributions. The two methodologies and the case study can be helpful references for both public and private sectors to deploy their feasibility-checking frameworks and deal with heterogeneous digital twins in general.
Background
Regional citrate anticoagulation (RCA) is the gold standard of anticoagulation for continuous renal replacement therapy but is rarely used for intermittent hemodialysis (IHD) in ICU. Few ...studies assessed the safety and efficacy of RCA during IHD in ICU; however, no data are available comparing RCA to heparin anticoagulation, which are commonly used for IHD. The aim of this study was to assess the efficacy and safety of RCA compared to heparin anticoagulation during IHD.
Methods
This retrospective single-center cohort study included consecutive ICU patients treated with either heparin anticoagulation (unfractionated or low-molecular-weight heparin) or RCA for IHD from July to September in 2015 and 2017. RCA was performed with citrate infusion according to blood flow and calcium infusion by diffusive influx from dialysate. Using a propensity score analysis, as the primary endpoint we assessed whether RCA improved efficacy, quantified with Kt/V from the ionic dialysance, compared to heparin anticoagulation. The secondary endpoint was safety. Exploratory analyses were performed on the changes in efficacy and safety between the implementation period (2015) and at long term (2017).
Results
In total, 208 IHD sessions were performed in 56 patients and were compared (124 RCA and 84 heparin coagulation). There was no difference in Kt/V between RCA and heparin (0.95 ± 0.38 vs. 0.89 ± 0.32;
p
= 0.98). A higher number of circuit clotting (12.9% vs. 2.4%;
p
= 0.02) and premature interruption resulting from acute high transmembrane pressure (21% vs. 7%;
p
= 0.02) occurred in the RCA sessions compared to the heparin sessions. In the propensity score-matching analysis, RCA was associated with an increased risk of circuit clotting (absolute differences = 0.10, 95% CI 0.03–0.18;
p
= 0.008). There was no difference in efficacy and safety between the two time periods (2015 and 2017).
Conclusion
RCA with calcium infusion by diffusive influx from dialysate for IHD was easy to implement with stable long-term efficacy and safety but did not improve efficacy and could be associated with an increased risk of circuit clotting compared to heparin anticoagulation in non-selected ICU patients. Randomized trials to determine the best anticoagulation for IHD in ICU patients should be conducted in a variety of settings.
In order to complement the picture of the atmospheric water cycle in the Southern Ocean, we have continuously monitored water vapor isotopes since January 2020 on Amsterdam Island in the Indian ...Ocean. We present here the first 2-year long water vapor isotopic record at this site. We show that the water vapor isotopic composition largely follows the water vapor mixing ratio, as expected in marine boundary layers. However, we detect 11 periods of a few days where there is a strong loss of correlation between water vapor delta.sup.18 O and water vapor mixing ratio as well as abrupt negative excursions of water vapor delta.sup.18 O. These excursions often occur toward the end of precipitation events. Six of these events show a decrease in gaseous elemental mercury, suggesting subsidence of air from a higher altitude.
Purpose
To identify the prognostic factors associated with mortality in heat-related illness.
Methods
Multi-center observational cohort-study in 16 emergency departments (ED) belonging to the ...teaching hospital network of the Paris area. The cohort comprised all patients admitted to one of the EDs during the August 2003 heat wave in Paris and having a core temperature >38.5°C. Baseline clinical and biological data in ED, patient’s course and 1-year survival rate were recorded. Potential prognostic factors associated with death were assessed by Cox proportional-hazards analysis.
Results
A total of 1,456 patients were included. Mean age was 79 ± 19 years. Critically ill conditions were noted in 391 patients (27%), but only 72 (5%) were admitted into an intensive care unit. The survival rate was 57% at 1 year as compared to an expected 90% (
P
< 0.001). Nine independent prognostic factors were identified: previous treatment with diuretics, living in an institution, age >80 years, cardiac disease, cancer, core temperature >40°C, systolic arterial pressure <100 mmHg, Glasgow coma scale <12 and transportation to hospital by ambulance. We defined three risk groups: low, intermediate and high risk, with a 1-year survival rate of 85, 61 and 18%, respectively.
Conclusions
We observed a low survival rate and developed a risk score based on easily obtained variables that may be useful to clinicians managing casualties from future heat waves.
Objective:Admission in the intensive care unit of the old patient with coronavirus disease 19 raises an ethical question concerning the scarce resources and their short-term ...mortality.Methods:Patients aged over 60 from 7 different intensive care units admitted between March 1, 2020 and May 6, 2020, with a diagnosis of coronavirus disease 19 were included in the cohort. Twenty variables were collected during the admission, such as age, severity (Simplified Acute Physiology Score SAPS II), several data on physiological status before intensive care unit comorbidities, evaluation of autonomy, frailty, and biological variables. The objective was to model the 30-day mortality with relevant variables, compute their odds ratio associated with their 95% CI, and produce a nomogram to easily estimate and communicate the 30-day mortality. The performance of the model was estimated with the area under the receiving operating curve.Results:We included 231 patients, among them 60 (26.0%) patients have died on the 30th day. The relevant variables selected to explain the 30-day mortality were Instrumental Activities of Daily Living (IADL) score (0.82 0.71-0.94), age 1.12 (1.07-1.18), SAPS II 1.05 (1.02-1.08), and dementia 6.22 (1.00-38.58). A nomogram was computed to visually represent the final model. Area under the receiving operating curve was at 0.833 (0.776-0.889).Conclusions:Age, autonomy, dementia, and severity at admission were important predictive variables for the 30-day mortality status, and the nomogram could help the physician in the decision-making process and the communication with the family.
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