Autonomous antenna tracking system for mobile symphonie ground stations

The implementation of a satellite tracking and antenna control system is described. Due to the loss of inclination control for the symphonie satellites, it became necessary to equip the parabolic antennas of the mobile Symphonie ground station with tracking facilities. For the relatively low required tracking accuracy of 0.5 dB, a low cost, step track system was selected. The step track system developed for this purpose and tested over a long period of time in 7 ground stations is based on a search step method with subsequent parabola interpolation. As compared with the real search step method, the system has the advantage of a higher pointing angle resolution, and thus a higher tracking accuracy. When the pilot signal has been switched off for a long period of time, as for instance after the eclipse, the antenna is repointed towards the satellite by an automatically initiated spiral search scan. The function and design of the tracking system are detailed, while easy handling and tracking results

Editorial: History of Neuroscience

International audienc

Deep Learning using K-space Based Data Augmentation for Automated Cardiac MR Motion Artefact Detection

Quality assessment of medical images is essential for complete automation of image processing pipelines. For large population studies such as the UK Biobank, artefacts such as those caused by heart motion are problematic and manual identification is tedious and time-consuming. Therefore, there is an urgent need for automatic image quality assessment techniques. In this paper, we propose a method to automatically detect the presence of motion-related artefacts in cardiac magnetic resonance (CMR) images. As this is a highly imbalanced classification problem (due to the high number of good quality images compared to the low number of images with motion artefacts), we propose a novel k-space based training data augmentation approach in order to address this problem. Our method is based on 3D spatio-temporal Convolutional Neural Networks, and is able to detect 2D+time short axis images with motion artefacts in less than 1ms. We test our algorithm on a subset of the UK Biobank dataset consisting of 3465 CMR images and achieve not only high accuracy in detection of motion artefacts, but also high precision and recall. We compare our approach to a range of state-of-the-art quality assessment methods.Comment: Accepted for MICCAI2018 Conferenc

The impact of preprinted prescription forms on medication prescribing errors in an ophthalmology clinic in northeast Thailand: a non-randomised interventional study

Objectives: To understand the incidence and types of medication prescribing errors in a low resource setting ophthalmology clinic and to determine the impact of a preprinted prescription based on the hospital formulary (FormularyScript) on medication prescribing errors. Design: Non-randomised interventional study. Setting: Ophthalmology clinic in a teaching hospital in northeast Thailand. Participants: 4349 handwritten prescriptions collected from October 2009 to December 2009, and 4146 FormularyScripts collected from February 2010 to May 2010. Primary and Secondary Outcome Measures: All prescriptions from the handwritten and FormularyScript groups were analysed for medication error rates by types (legibility, ambiguous, incomplete, abbreviation and accuracy) and subtypes (drug name, strength, which eye, route and dispensed amount). Results: Comparison of error rates in the two groups showed a 10-fold reduction in the overall error rate using FormularyScript (32.9%–3.5%, p<0.001). FormularyScripts were associated with statistically significant (p<0.001) decreases in the following error types: legibility (16.1%–0.1%), incomplete (16.1%–0.1%) and abbreviation (3.1%–0.3%). There was no statistically significant change in accuracy errors (0.8%–0.6%, p=0.21). Ambiguous errors increased with FormularyScripts (0.6%–2.5%, p<0.001), likely due to the introduction of new ways to make errors. Decreases were seen in all legibility, abbreviation and accuracy error subtypes, and four out of six incomplete error subtypes. There were statistically significant increases in both ambiguous error subtypes: which eye (0.3%–2.5%, p<0.001) and drug name (0.3%–0.6%, p=0.03). Conclusions: In our study population, outpatient medication prescribing errors were common and primarily due to legibility and incomplete error types. A preprinted prescription form has the potential to decrease medication prescribing errors related to legibility, incomplete prescribing information and use of unacceptable abbreviations without changing the overall rate of accuracy errors. However, new error types can occur

GridCertLib: a Single Sign-on Solution for Grid Web Applications and Portals

This paper describes the design and implementation of GridCertLib, a Java library leveraging a Shibboleth-based authentication infrastructure and the SLCS online certificate signing service, to provide short-lived X.509 certificates and Grid proxies. The main use case envisioned for GridCertLib, is to provide seamless and secure access to Grid/X.509 certificates and proxies in web applications and portals: when a user logs in to the portal using Shibboleth authentication, GridCertLib can automatically obtain a Grid/X.509 certificate from the SLCS service and generate a VOMS proxy from it. We give an overview of the architecture of GridCertLib and briefly describe its programming model. Its application to some deployment scenarios is outlined, as well as a report on practical experience integrating GridCertLib into portals for Bioinformatics and Computational Chemistry applications, based on the popular P-GRADE and Django softwares.Comment: 18 pages, 1 figure; final manuscript accepted for publication by the "Journal of Grid Computing

Effects of Alkalinization and Rehydration on Plasma Potassium Concentrations in Neonatal Calves with Diarrhea

BackgroundIncreased plasma potassium concentrations (K+) in neonatal calves with diarrhea are associated with acidemia and severe clinical dehydration and are therefore usually corrected by intravenous administration of fluids containing sodium bicarbonate. ObjectivesTo identify clinical and laboratory variables that are associated with changes of plasma K+ during the course of treatment and to document the plasma potassium-lowering effect of hypertonic (8.4%) sodium bicarbonate solutions. AnimalsSeventy-one neonatal diarrheic calves. MethodsProspective cohort study. Calves were treated according to a clinical protocol using an oral electrolyte solution and commercially available packages of 8.4% sodium bicarbonate (250-750mmol),0.9% saline (5-10L),and 40% dextrose (0.5L) infusion solutions. ResultsInfusions with 8.4% sodium bicarbonate solutions in an amount of 250-750mmol had an immediate and sustained plasma potassium-lowering effect. One hour after the end of such infusions or the start of a sodium bicarbonate containing constant drip infusion, changes of plasma K+ were most closely correlated to changes of venous blood pH, plasma sodium concentrations and plasma volume (r=-0.73,-0.57,-0.53;P<.001). Changes of plasma K+ during the subsequent 23hours were associated with changes of venous blood pH, clinical hydration status (enophthalmos) and serum creatinine concentrations (r=-0.71, 0.63, 0.62;P<.001). Conclusions and Clinical ImportanceThis study emphasizes the importance of alkalinization and the correction of dehydration in the treatment of hyperkalemia in neonatal calves with diarrhea

Effects of Alkalinization and Rehydration on Plasma Potassium Concentrations in Neonatal Calves with Diarrhea

BackgroundIncreased plasma potassium concentrations (K+) in neonatal calves with diarrhea are associated with acidemia and severe clinical dehydration and are therefore usually corrected by intravenous administration of fluids containing sodium bicarbonate. ObjectivesTo identify clinical and laboratory variables that are associated with changes of plasma K+ during the course of treatment and to document the plasma potassium-lowering effect of hypertonic (8.4%) sodium bicarbonate solutions. AnimalsSeventy-one neonatal diarrheic calves. MethodsProspective cohort study. Calves were treated according to a clinical protocol using an oral electrolyte solution and commercially available packages of 8.4% sodium bicarbonate (250-750mmol),0.9% saline (5-10L),and 40% dextrose (0.5L) infusion solutions. ResultsInfusions with 8.4% sodium bicarbonate solutions in an amount of 250-750mmol had an immediate and sustained plasma potassium-lowering effect. One hour after the end of such infusions or the start of a sodium bicarbonate containing constant drip infusion, changes of plasma K+ were most closely correlated to changes of venous blood pH, plasma sodium concentrations and plasma volume (r=-0.73,-0.57,-0.53;P<.001). Changes of plasma K+ during the subsequent 23hours were associated with changes of venous blood pH, clinical hydration status (enophthalmos) and serum creatinine concentrations (r=-0.71, 0.63, 0.62;P<.001). Conclusions and Clinical ImportanceThis study emphasizes the importance of alkalinization and the correction of dehydration in the treatment of hyperkalemia in neonatal calves with diarrhea

Risk Factors for the Development of Hypokalemia in Neonatal Diarrheic Calves

BackgroundNeonatal diarrheic calves have a clear negative potassium balance because of intestinal losses and decreased milk intake but in the presence of acidemia, they usually show normokalemic or hyperkalemic plasma concentrations. ObjectivesTo assess whether marked hypokalemia occurs in response to the correction of acidemia and dehydration and to identify factors that are associated with this condition. AnimalsEighty-three calves with a clinical diagnosis of neonatal diarrhea. MethodsProspective cohort study. Calves were treated according to a clinical protocol using an oral electrolyte solution and commercially available packages of 8.4% sodium bicarbonate, 0.9% saline and 40% dextrose infusion solutions. ResultsThe proportion of hypokalemic calves after 24hours of treatment (19.3%) was twice as great as it was on admission to the hospital. Plasma K+ after 24hours of treatment was not significantly correlated to venous blood pH values at the same time but positively correlated to venous blood pH values on admission (r=0.51, P<.001). Base excess on admission (Odds ratio [OR]=0.81, 95% confidence interval [CI]=0.70-0.94),duration of diarrhea (OR=1.37, 95% CI=1.05-1.80),milk intake during hospitalization (OR=0.54, 95% CI=0.37-0.79) and plasma sodium concentrations after 24hours (OR=1.12, 95% CI=1.01-1.25) were identified to be independently associated (P<.05) with a hypokalemic state after 24hours of treatment. Conclusions and Clinical ImportanceFindings of this study suggest that marked depletion of body potassium stores is evident in diarrheic calves that suffered from marked metabolic acidosis, have a low milk intake and a long history of diarrhea

Polymer reptation and nucleosome repositioning

We consider how beads can diffuse along a chain that wraps them, without becoming displaced from the chain; our proposed mechanism is analogous to the reptation of "stored length" in more familiar situations of polymer dynamics. The problem arises in the case of globular aggregates of proteins (histones) that are wound by DNA in the chromosomes of plants and animals; these beads (nucleosomes) are multiply wrapped and yet are able to reposition themselves over long distances, while remaining bound by the DNA chain.Comment: 9 pages, including 2 figures, to be published in Phys. Rev. Let

Impact of obesity on global and regional systolic function in children: a CMR study

International audiencen.