Sensorfusion und Regelung eines Roboters am kontinuierlich bewegten Band

Der Artikel beschreibt die Montage eines Anbauteils an ein kontinuierlich bewegtes Basisbauteil, dessen Bewegung durch unterschiedliche Sensoren gemessen wird. Dabei werden u. a. die Ergebnisse einer Bildverarbeitung mit den Auslenkungen eines nachgiebigen Kraft- Momentensensors fusioniert. Aus den Bahnpunkten wird dann eine geglättete Solltrajektorie für das Anbauteil bestimmt. Die Regelung des Roboters wird durch Vorsteuerungen ergänzt, die die dynamischen Verzögerungen und Schwingungen von Roboter und Endeffektor prädiktiv kompensieren

Indomethacin decreases viscosity of gallbladder bile in patients with cholesterol gallstone disease

There is experimental evidence that inhibition of cyclooxygenase with nonsteroidal anti-inflammatory drugs may decrease cholesterol gall-stone formation and mitigate biliary pain in gall-stone patients. The mechanisms by which NSAIDs exert these effect are unclear. In a prospective, controlled clinical trial we examined the effects of oral indomethacin on the composition of human gall-bladder bile. The study included 28 patients with symptomatic cholesterol or mixed gallstones. Of these, 8 were treated with 3 × 25 mg indomethacin daily for 7 days prior to elective cholecystectomy while 20 received no treatment and served as controls. Bile and tissue samples from the gallbladder were obtained during cholecystectomy. Indomethacin tissue levels in the gallbladder mucosa, as assessed by HPLC, were 1.05±0.4 ng/mg wet weight, a concentration known to inhibit effectively cyclooxygenase activity. Nevertheless, no differences between the treated and untreated groups were found in the concentrations of biliary mucus glycoprotein (0.94±0.27 versus 0.93±0.32 mg/ml) or total protein (5.8±0.9 versus 6.4±1.3 mg/ml), cholesterol saturation (1.3±0.2 versus 1.5±0.2), or nucleation time (2.0±3.0 versus 1.5±2.0 days). However, biliary viscosity, measured using a low-shear rotation viscosimeter, was significantly lower in patients receiving indomethacin treatment (2.9±0.6 versus 5.6±1.2 mPa.s; P < 0.02). In conclusion, in man oral indomethacin decreases bile viscosity without alteration of bile lithogenicity or biliary mucus glycoprotein content. Since mucus glycoproteins are major determinants of bile viscosity, an alteration in mucin macromolecular composition may conceivably cause the indomethacin-induced decrease in biliary viscosity and explain the beneficial effects of nonsteroidal anti-inflammatory drugs in gallstone disease

Amoklauf in der Schule: allgemeine Überlegungen aus speziellem Anlass

'Aus Anlass des sogenannten 'Amoklaufs' wird die These vertreten, dass bei der Suche nach Erklärungen und Lösungsmöglichkeiten mindestens drei Problembereiche voneinander unterschieden werden müssen. Insbesondere ist von dem Phänomen 'Amok' das Thema 'Jugendgewalt' genau zu unterscheiden; dieses wiederum überschneidet sich nur teilweise mit der Problematik von aggressivem und antisozialem Verhalten in der Schule und den pädagogischen Reaktionsmöglichkeiten. Abschließend werden Herausforderungen für die empirische Forschung und Implikationen für die praktische Arbeit diskutiert.' (Autorenreferat)'With reference to the so-called 'amok run' of Erfurt it is argued that for the identification of proper explanations and solutions at least three perspectives have to be differentiated. In particular, the phenomenon of 'amok' has to be separated from juvenile violence, which, in turn, only partly overlaps with problems of aggressive and antisocial behavior in schools and educational answers to it. Finally, challenges for empirical research and practical implications are discussed.' (author's abstract)

Getting virtual 3D landscapes out of the lab

Increasingly realistic virtual three dimensional (3D) models have been created that demonstrate a variety of landscape designs. They have supported a more collaborative and participative approach in planning and design. However, these 3D landscape models are often developed for use in bespoke virtual reality labs that tie the models to expensive graphics hardware, or complex arrays of screens, with the viewer spatially detached from the actual site. Given the increase in prevalence of advanced “smartphone” and tablet technology with GPS and compass functionality, this paper demonstrates two methods for on-demand dissemination of existing virtual 3D landscape models using: (1) a touch based interface with integrated mapping; (2) a standard web browser interface on mobile phones. The latter method demonstrates the potential to reduce the complexity of accessing an existing 3D landscape model on-site to simply pointing a smartphone in a particular direction, loading a web page and seeing the relevant view of the model as an image. A prototype system was developed to demonstrate both methods successfully, but it was also ascertained that the accuracy of GPS positional data can have a negative effect on the browser based method. Finally, potential developments are presented exploring the future of the technology underpinning the method and possible extensions to the prototype as a technique for increasing public participation in planning and design

Using MOST to reveal the secrets of the mischievous Wolf-Rayet binary CV Ser

The WR binary CV Serpentis (= WR113, WC8d + O8-9IV) has been a source of mystery since it was shown that its atmospheric eclipses change with time over decades, in addition to its sporadic dust production. The first high-precision time-dependent photometric observations obtained with the MOST space telescope in 2009 show two consecutive eclipses over the 29d orbit, with varying depths. A subsequent MOST run in 2010 showed a seemingly asymmetric eclipse profile. In order to help make sense of these observations, parallel optical spectroscopy was obtained from the Mont Megantic Observatory (2009, 2010) and from the Dominion Astrophysical Observatory (2009). Assuming these depth variations are entirely due to electron scattering in a beta-law wind, an unprecedented 62% increase in mass-loss rate is observed over one orbital period. Alternatively, no change in mass-loss rate would be required if a relatively small fraction of the carbon ions in the wind globally recombined and coaggulated to form carbon dust grains. However, it remains a mystery as to how this could occur. There also seems to be evidence for the presence of corotating interaction regions (CIR) in the WR wind: a CIR-like signature is found in the light curves, implying a potential rotation period for the WR star of 1.6 d. Finally, a new circular orbit is derived, along with constraints for the wind collision.Comment: 11 pages, 11 figures, 5 table

Timing and Navigation in UAVs: Synchronization of UAV Swarms and Testing GPS Error Effects on GNSS Reception

Precise timing and precise location information are provided by Global Navigation Satellite Systems (GNSS) and play a crucial role in the positioning, navigation and data acquisition of most Unmanned Aerial Vehicles (UAV). GNSS functions include the following applications in UAVs: time-stamping and geo-referencing of collected data and images, synchronization of swarm flying and follow-me flights, determination of position and attitude in-flight, flight trajectory by following a pre-defined number of waypoints, mission planning, return home automatically without external control, avoidance of obstacles and geo-fencing.&nbsp; Some of these critical operations have implications for the safety of the UAV, the surrounding environment and health and safety of people, for example UAVs threatening to bring down aircrafts&nbsp; at airports, which are no-fly zones for UAVs. The appropriate GNSS based function to avoid this is geo-fencing. Another example is obstacle avoidance to prevent collisions and damages both for the UAV and the obstacle, e.g. anything from a window pane, tree, human being, to a power line. In order to ensure health and safety it is thus important to ensure correct function of the navigation and the timing, under a wide variety of circumstances, and in different signal environments. There can be signal disturbances, such as obscurations by buildings or reflected GNSS signals, called multipath. The performance of timing and navigation based on GPS/GNSS can be tested and verified in a controlled and repeatable way in the laboratory with different types of test equipment. We will give an introduction to a wide range of potential threats to GNSS Positioning, navigation and timing and an overview of different test methods. In addition, we are presenting a method for time synchronization of drones to enable safe swarm and follow flights in UAVs

Seed Amplification Assay as a Diagnostic Tool in Newly-Diagnosed Parkinson's Disease

Seed amplification assays (SAA) are the first credible molecular assay for Parkinson’s disease (PD). However, the value of SAA to support the clinicians’ initial diagnosis of PD is not clear. In our study, we analyzed cerebrospinal fluid samples from 121 PD patients recruited through population screening methods and taken within a median delay of 38 days from diagnosis and 51 normal controls without neurodegenerative disease. SAA yielded a sensitivity of 82.6% (95% CI, 74.7% – 88.9%) and specificity of 88.2% (95% CI, 76.1% – 95.6%). These results highlight the potential of SAA to support the initial diagnosis of PD in clinical practice and research.publishedVersio