376 research outputs found

    Knowledge-based monitoring of the pointing control system on the Hubble space telescope

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    A knowledge-based system for the real time monitoring of telemetry data from the Pointing and Control System (PCS) of the Hubble Space Telescope (HST) that enables the retention of design expertise throughout the three decade project lifespan by means other than personnel and documentation is described. The system will monitor performance, vehicle status, success or failure of various maneuvers, and in some cases diagnose problems and recommend corrective actions using a knowledge base built using mission scenarios and the more than 4,500 telemetry monitors from the HST

    Designing a mobile system for lifelong learning on the move

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    Abstract The Life-long Learning Initiative seeks to fulfil a variety of learning needs for Shanghai citizens. Given the popularity of mobile devices in Shanghai, the ability to provide learning in informal settings through mobile devices is a key objective and challenge of the Initiative. In order to learn how to develop usable learning content for lifelong learners on the move, a set of design principles from both pedagogical and usability concerns was identified. Next, a pilot system, based on the design principles, was developed to implement two prototype lessons. Five subjects were recruited to test each prototype lesson using a heuristic walkthrough method and a focus group meeting. Users' feedback showed that both the practical and the micro principles were valued as a method of integrating learning activity into informal settings in their daily lives. Audio was preferred as well. Technical usability concerns which are consistent with previous web experience were also identified. This research builds new knowledge about design principles for lifelong learning on the move and is a milestone in the development of the future learning resource bank for Shanghai citizens

    On minimal extensions of rings

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    Given two rings R⊆SR \subseteq S, SS is said to be a minimal ring extension of RR if RR is a maximal subring of SS. In this article, we study minimal extensions of an arbitrary ring RR, with particular focus on those possessing nonzero ideals that intersect RR trivially. We will also classify the minimal ring extensions of prime rings, generalizing results of Dobbs, Dobbs & Shapiro, and Ferrand & Olivier on commutative minimal extensions.Comment: 25 page

    Patterns of use of adjunctive therapies in patients with early moderate- severe Acute Respiratory Distress syndrome: Insights from the LUNG SAFE Study

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    Background: Adjunctive strategies are an important part of the management of ARDS. However, their application in clinical practice remains inconsistent. Research Question: We wished to determine the frequency and patterns of use of adjunctive strategies in patients with moderate to severe ARDS (PaO2/FIO2 [P/F ratio] < 150) enrolled into the Large observational study to UNderstand the Global impact of Severe Acute respiratory FailurE (LUNG SAFE) study. Study Design and Methods: The LUNG SAFE study was an international, multicenter, prospective cohort study of patients with severe respiratory failure, conducted in 2014 in 459 ICUs from 50 countries. The primary objective of this substudy was to determine the frequency of use of widely available (neuromuscular blockade, prone position) adjuncts vs adjuncts requiring specialized equipment (extracorporeal membrane oxygenation, inhaled vasodilators, high-frequency ventilation) in patients in the first 48 h of moderate to severe ARDS (P/F ratio < 150). Results: Of 1,146 patients on invasive ventilation with moderate to severe ARDS, 811 patients (71%) received no adjunct within 48 h of ARDS onset. Of 335 (29%) that received adjunctive strategies, 252 (75%) received a single strategy, and 83 (25%) receiving more than one adjunct. Of ARDS nonsurvivors, 67% did not receive any adjunctive strategy in the first 48 h. Most patients (67%) receiving specialized adjuncts did not receive prone positioning or neuromuscular blockade. Patients that received adjuncts were more likely to have their ARDS recognized, be younger and sicker, have pneumonia, be more difficult to ventilate, and be in a European high-income country than those that did not receive adjuncts. Interpretation: Three in 10 patients with moderate to severe ARDS, and only one-third of nonsurvivors, received adjunctive strategies over the first 48 h of ARDS. A more consistent and evidence-driven approach to adjunct use may reduce costs and improve outcomes in patients with moderate to severe ARDS. Trial Registry: ClinicalTrials.gov; No.: NCT02010073; URL: www.clinicaltrials.go

    Determination of the efficacy and side-effect profile of lower doses of intrathecal morphine in patients undergoing total knee arthroplasty

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    <p>Abstract</p> <p>Background</p> <p>Intrathecal (IT) morphine provides excellent post-operative analgesia, but causes multiple side effects including nausea and vomiting (PONV), pruritus and respiratory depression, particularly at higher doses. The lowest effective dose of spinal morphine in patients undergoing total knee arthroplasty is not known.</p> <p>Methods</p> <p>We evaluated the analgesic efficacy and side effect profile of 100 – 300 ÎŒg IT morphine in patients undergoing elective total knee replacement in this prospective, randomized, controlled, double-blind study. Sixty patients over the age of 60 undergoing elective knee arthroplasty were enrolled. Patients were randomized to receive spinal anaesthesia with 15 mg Bupivacaine and IT morphine in three groups: (i) 100 ÎŒg; (ii) 200 ÎŒg; and (iii) 300 ÎŒg.</p> <p>Results</p> <p>Both 200 ÎŒg and 300 ÎŒg IT morphine provided comparable levels of postoperative analgesia. However, patients that received 100 ÎŒg had greater pain postoperatively, with higher pain scores and a greater requirement for supplemental morphine. There were no differences between groups with regard to PONV, pruritus, sedation, respiratory depression or urinary retention.</p> <p>Conclusion</p> <p>Both 200 ÎŒg and 300 ÎŒg provided comparable postoperative analgesia, which was superior to that provided by 100 ÎŒg IT morphine in patients undergoing total knee arthroplasty. Based on these findings, we recommend that 200 ÎŒg IT morphine be used in these patients.</p> <p>Trial registration</p> <p>ClinicalTrials.gov Identifier NCT00695045</p

    Epidemiology, patterns of care, and mortality for patients with acute respiratory distress syndrome in intensive care units in 50 countries

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    IMPORTANCE: Limited information exists about the epidemiology, recognition, management, and outcomes of patients with the acute respiratory distress syndrome (ARDS). OBJECTIVES: To evaluate intensive care unit (ICU) incidence and outcome of ARDS and to assess clinician recognition, ventilation management, and use of adjuncts-for example prone positioning-in routine clinical practice for patients fulfilling the ARDS Berlin Definition. DESIGN, SETTING, AND PARTICIPANTS:The Large Observational Study to Understand the Global Impact of Severe Acute Respiratory Failure (LUNG SAFE) was an international, multicenter, prospective cohort study of patients undergoing invasive or noninvasive ventilation, conducted during 4 consecutive weeks in the winter of 2014 in a convenience sample of 459 ICUs from 50 countries across 5 continents. EXPOSURES:Acute respiratory distress syndrome. MAIN OUTCOMES AND MEASURES: The primary outcome was ICU incidence of ARDS. Secondary outcomes included assessment of clinician recognition of ARDS, the application of ventilatory management, the use of adjunctive interventions in routine clinical practice, and clinical outcomes from ARDS. RESULTS: Of 29,144 patients admitted to participating ICUs, 3022 (10.4%) fulfilled ARDS criteria. Of these, 2377 patients developed ARDS in the first 48 hours and whose respiratory failure was managed with invasive mechanical ventilation. The period prevalence of mild ARDS was 30.0% (95% CI, 28.2%-31.9%); of moderate ARDS, 46.6% (95% CI, 44.5%-48.6%); and of severe ARDS, 23.4% (95% CI, 21.7%-25.2%). ARDS represented 0.42 cases per ICU bed over 4 weeks and represented 10.4% (95% CI, 10.0%-10.7%) of ICU admissions and 23.4% of patients requiring mechanical ventilation. Clinical recognition of ARDS ranged from 51.3% (95% CI, 47.5%-55.0%) in mild to 78.5% (95% CI, 74.8%-81.8%) in severe ARDS. Less than two-thirds of patients with ARDS received a tidal volume 8 of mL/kg or less of predicted body weight. Plateau pressure was measured in 40.1% (95% CI, 38.2-42.1), whereas 82.6% (95% CI, 81.0%-84.1%) received a positive end-expository pressure (PEEP) of less than 12 cm H2O. Prone positioning was used in 16.3% (95% CI, 13.7%-19.2%) of patients with severe ARDS. Clinician recognition of ARDS was associated with higher PEEP, greater use of neuromuscular blockade, and prone positioning. Hospital mortality was 34.9% (95% CI, 31.4%-38.5%) for those with mild, 40.3% (95% CI, 37.4%-43.3%) for those with moderate, and 46.1% (95% CI, 41.9%-50.4%) for those with severe ARDS. CONCLUSIONS AND RELEVANCE: Among ICUs in 50 countries, the period prevalence of ARDS was 10.4% of ICU admissions. This syndrome appeared to be underrecognized and undertreated and associated with a high mortality rate. These findings indicate the potential for improvement in the management of patients with ARDS

    Epidemiology, ventilation management and outcomes of COVID–19 ARDS patients versus patients with ARDS due to pneumonia in the Pre–COVID era

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    Background: Ventilation management may differ between COVID–19 ARDS (COVID–ARDS) patients and patients with pre–COVID ARDS (CLASSIC–ARDS); it is uncertain whether associations of ventilation management with outcomes for CLASSIC–ARDS also exist in COVID–ARDS. Methods: Individual patient data analysis of COVID–ARDS and CLASSIC–ARDS patients in six observational studies of ventilation, four in the COVID–19 pandemic and two pre–pandemic. Descriptive statistics were used to compare epidemiology and ventilation characteristics. The primary endpoint were key ventilation parameters; other outcomes included mortality and ventilator–free days and alive (VFD–60) at day 60. Results: This analysis included 6702 COVID–ARDS patients and 1415 CLASSIC–ARDS patients. COVID–ARDS patients received lower median VT (6.6 [6.0 to 7.4] vs 7.3 [6.4 to 8.5] ml/kg PBW; p < 0.001) and higher median PEEP (12.0 [10.0 to 14.0] vs 8.0 [6.0 to 10.0] cm H2O; p < 0.001), at lower median ΔP (13.0 [10.0 to 15.0] vs 16.0 [IQR 12.0 to 20.0] cm H2O; p < 0.001) and higher median Crs (33.5 [26.6 to 42.1] vs 28.1 [21.6 to 38.4] mL/cm H2O; p < 0.001). Following multivariable adjustment, higher ΔP had an independent association with higher 60–day mortality and less VFD–60 in both groups. Higher PEEP had an association with less VFD–60, but only in COVID–ARDS patients. Conclusions: Our findings show important differences in key ventilation parameters and associations thereof with outcomes between COVID–ARDS and CLASSIC–ARDS. Trial registration: Clinicaltrials.gov (identifier NCT05650957), December 14, 2022
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