46 research outputs found

    Search for a Solution of the Pioneer Anomaly

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    In 1972 and 1973 the Pioneer 10 and 11 missions were launched. They were the first to explore the outer solar system and achieved stunning breakthroughs in deep-space exploration. But beginning in about 1980 an unmodeled force of \sim 8 \times 10^{-8} cm/s^2, directed approximately towards the Sun, appeared in the tracking data. It later was unambiguously verified as being in the data and not an artifact. The cause remains unknown (although radiant heat remains a likely origin). With time more and more effort has gone into understanding this anomaly (and also possibly related effects). We review the situation and describe ongoing programs to resolve the issue.Comment: 24 pages 8 figure

    Solid Propellant Pulsed Plasma Propulsion System Design

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    Effect of Propellant Temperature on Efficiency in the Pulsed Plasma Thruster

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    Pancreatic exocrine insufficiency after bariatric surgery

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    Background: Chronic abdominal complaints after bariatric surgery may be explained by pancreatic exocrine insufficiency (PEI). Objectives: We aimed to evaluate the clinical value of the Pancreatic Exocrine Insufficiency Questionnaire (PEI-Q) as a screening tool to identify patients with a high probability of having PEI. Setting: Outpatient clinic for bariatric surgery. Methods: Patients scheduled for a screening or follow-up appointment were asked to complete the PEI-Q and the Gastrointestinal Quality of Life Index questionnaire (GIQLI). Postoperative patients with a high PEI-Q score (0,6) were offered a fecalelastase (FE) test (abnormal if <200 μg/g). Results: Between June 2020 and February 2021, a total of 1600 of 1629 PEI-Qs were completed, 1073 (67%) of which after surgery. The postoperative group consisted mostly of females (81.9%), aged 49.0 ± 10.6 years, with a total weight loss of 30.3% ± 8.8%. Among them, 63.4% had abnormal PEI-Q scores compared with 34.9% before surgery (P < .01). In contrast, the median GIQLI score increased (119 [interquartile range (IQR), 107–129.25] versus 110 [IQR, 95–121.75]) before surgery (P < .01). Additionally, 310 FE tests were performed, of which only 11.9% was suggestive of PEI. No correlation was found between the PEI-Q scores and FE levels (c-index .55). Conclusion: The PEI-Q in its current version is not able to distinguish complaints of PEI and bariatric surgery itself and therefore cannot be used as a screening tool for PEI. The specificity of the FE test seems to be reduced after surgery. Future research should include a more direct pancreatic function test, which may provide more insight into PEI after bariatric surgery

    Risk of venous thromboembolism and bleeding after major surgery for ovarian cancer: standard in-hospital versus extended duration of thromboprophylaxis

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    BACKGROUND: Venous thromboembolism (VTE) is a frequent complication in patients with ovarian cancer after major surgery. Based on limited data, international guidelines recommend extended thromboprophylaxis for up to 28 days. OBJECTIVES: To assess the incidence of VTE and bleeding within 30 days following major surgery in patients with ovarian cancer and to evaluate the association between VTE and thromboprophylaxis duration. METHODS: This was a single-center, retrospective, "before-after" cohort study in patients with ovarian cancer undergoing major surgery. Before July 2019, the local protocol mandated a standard course of thromboprophylaxis during hospital stay only. From July 2019 onward, patients received extended thromboprophylaxis for 28 days. The cumulative incidences of VTE and major bleeding within 30 days after surgery were estimated using the Kaplan-Meier method, with 95% confidence intervals (CIs). Cox regression analysis was performed to evaluate the association between thromboprophylaxis duration and VTE incidence. RESULTS: Between January 2018 and December 2020, 250 women were included, of which 118 (47.2%) received extended and 132 (52.8%) standard thromboprophylaxis. During follow-up, 12 patients developed VTE (cumulative incidence, 4.8%; 95% CI, 2.1-7.4) and 2 major bleeding (cumulative incidence 0.8%; 95% CI, 0.0-1.9). Compared with standard thromboprophylaxis, VTE incidence was numerically lower with extended duration of thromboprophylaxis (5/118 [4.2%] vs 7/132 [5.3%]) but not significantly different (hazard ratio, 0.80; 95% CI, 0.25-2.52). The risk of major bleeding was similar in both groups (1/118 [0.8%] vs 1/132 [0.8%]; hazard ratio, 1.12; 95% CI, 0.07-17.89). CONCLUSIONS: The cumulative VTE incidence in patients with ovarian cancer following major surgery was considerable. Extended thromboprophylaxis was safe and associated with a numerically lower risk of VTE but not significantly different

    Risk of venous thromboembolism and bleeding after major surgery for ovarian cancer: standard in-hospital versus extended duration of thromboprophylaxis

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    BACKGROUND: Venous thromboembolism (VTE) is a frequent complication in patients with ovarian cancer after major surgery. Based on limited data, international guidelines recommend extended thromboprophylaxis for up to 28 days. OBJECTIVES: To assess the incidence of VTE and bleeding within 30 days following major surgery in patients with ovarian cancer and to evaluate the association between VTE and thromboprophylaxis duration. METHODS: This was a single-center, retrospective, "before-after" cohort study in patients with ovarian cancer undergoing major surgery. Before July 2019, the local protocol mandated a standard course of thromboprophylaxis during hospital stay only. From July 2019 onward, patients received extended thromboprophylaxis for 28 days. The cumulative incidences of VTE and major bleeding within 30 days after surgery were estimated using the Kaplan-Meier method, with 95% confidence intervals (CIs). Cox regression analysis was performed to evaluate the association between thromboprophylaxis duration and VTE incidence. RESULTS: Between January 2018 and December 2020, 250 women were included, of which 118 (47.2%) received extended and 132 (52.8%) standard thromboprophylaxis. During follow-up, 12 patients developed VTE (cumulative incidence, 4.8%; 95% CI, 2.1-7.4) and 2 major bleeding (cumulative incidence 0.8%; 95% CI, 0.0-1.9). Compared with standard thromboprophylaxis, VTE incidence was numerically lower with extended duration of thromboprophylaxis (5/118 [4.2%] vs 7/132 [5.3%]) but not significantly different (hazard ratio, 0.80; 95% CI, 0.25-2.52). The risk of major bleeding was similar in both groups (1/118 [0.8%] vs 1/132 [0.8%]; hazard ratio, 1.12; 95% CI, 0.07-17.89). CONCLUSIONS: The cumulative VTE incidence in patients with ovarian cancer following major surgery was considerable. Extended thromboprophylaxis was safe and associated with a numerically lower risk of VTE but not significantly different
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