Vertical structures induced by embedded moonlets in Saturn's rings: the gap region

We study the vertical extent of propeller structures in Saturn's rings. Our focus lies on the gap region of the propeller and on non-inclined propeller moonlets. In order to describe the vertical structure of propellers we extend the model of Spahn and Sremcevic (2000) to include the vertical direction. We find that the gravitational interaction of ring particles with the non-inclined moonlet does not induce considerable vertical excursions of ring particles, but causes a considerable thermal motion in the ring plane. We expect ring particle collisions to partly convert the lateral induced thermal motion into vertical excursions of ring particles. For the gap region of the propeller, we calculate gap averaged propeller heights on the order of 0.7 Hill radii, which is of the order of the moonlet radius. In our model the propeller height decreases exponentially until viscous heating and collisional cooling balance. We estimate Hill radii of 370m and 615m for the propellers Earhart and Bleriot. Our model predicts about 120km for the azimuthal extent of the Earhart propeller at Saturn's 2009 equinox, being consistent with values determined from Cassini images

Ernst Lieber als Parlamentarier

ERNST LIEBER ALS PARLAMENTARIER Ernst Lieber als Parlamentarier / Spahn, Martin (Public Domain) ( - ) Cover front ( - ) Title page ( - ) Dedication ( - ) Contents ( - ) Erster Abschnitt. Eintritt ins öffentliche und parlamentarische Leben. 1838-1878 ([1]) Zweiter Abschnitt. Entwickelung des Reichs. Sozialpolitische Tätigkeit. Kampf gegen das alte Preußen. 1878-1888 ([12]) Dritter Abschnitt. Übernahme der Parteiführung. Schulgesetz und Wehrvorlage. 1888-1893 ([24]) Vierter Abschnitt. Russischer Handelsvertrag. Reichsfinanreform. Winter 1893/94 ([36]) Fünfter Abschnitt. Mitarbeit am Reiche. Bürgerliches Gesetzbuch und Flottenvorlage. 1894-1898 ([44]) Sechster Abschnitt. Der "Reichsregent" ([55]) Siebenter Abschnitt. Preußen und das Reich. Lebensende. 1898-1902 ([65]) Schlußbemerkung (6) Cover back ( - ) ColorChart ( -

Mechanische Sehnenzugtestung nach Bunnell-Naht Rekonstruktion im ex vivo Schweinemodell

Das Ziel der experimentellen Arbeit war es, die etablierte Sehnennahttechnik nach Bunnell in modifizierter Ausführung unter Verwendung verschiedenen Nahtmaterials (LabralTape™ und FiberTape, Firma Arthrex) im Achillessehnenmodell zu testen. Hierfür sollte anhand axialer mechanischer Zugversuche der Unterschied zwischen LabralTape™ und FiberTape in Bezug auf Maximalkraft (Fmax) und Kraft bei 3mm-Dehiszenzspaltbildung (F3mm) ermittelt werden. Ein Kraftunterschied von 50 N wurde als klinisch relevant festgelegt. Es wurden axiale Sehnenzugversuche durchgeführt. Als Versuchssehnen dienten 134 tiefe Flexorensehnen von hinteren rechten Schweinefüßen. Es wurde eine Materialprüfmaschine vom Typ zwickiLine 2.5TN verwendet. Die Analyse der 3mm-Dehiszenzspaltbildung erfolgte mit Hilfe einer Pontos 5M Hochgeschwindigkeitskamera. Die Anzahl (N) an Versuchen sowie die Teststatistik leiteten sich aus der vorausgehenden Fallzahlplanung ab. Es konnte gezeigt werden, dass FiberTape signifikant höhere Maximalkraftwerte ermöglicht (p < 0,001). Der Median für Fmax bei LabralTape™ lag bei 554,6 N. Bei FiberTape lag der Median für Fmax bei 650,2 N. Die Kraft bei 3mm-Dehiszenzspaltbildung (F3mm) verhielt sich bei LabralTape™ und FiberTape dagegen sehr ähnlich. Hier konnte kein signifikanter Unterschied festgestellt werden (p = 0,227). Der Median für F3mm lag bei LabralTape™ bei 144,7 N. Bei FiberTape lag der Median für F3mm bei 135,1 N. FiberTape führte in 100 % der Fälle zum Testversagen durch Sehnenausriss. LabralTape™ versagte in ca. 57 % der Fälle aufgrund eines Fadenrisses. Im Vergleich zu Sehnenzugversuchen anderer Studien wiesen LabralTape™ und FiberTape in Kombination mit der Bunnell-Nahttechnik eine äußerst hohe mechanische Belastbarkeit auf. Beim Nahtmaterial handelte es sich um nicht-resorbierbare Polyethylenfäden. Sie bieten ein hohes Potential für eine stabile Versorgung von akuten Achillessehnenrupturen. Die Ergebnisse der Arbeit werden dadurch limitiert, dass es sich um ex vivo Schweinemodellversuche von Achillessehnenrupturen handelt. Bei den Versuchen wirkten allein axiale Kräfte auf die Sehnen. Weiterführende Tests mit zyklischen Belastungen müssen zeigen, in wie weit sich das Nahtmaterial auch für in vivo Bedingungen eignet

C-MAC videolaryngoscope compared with direct laryngoscopy for rapid sequence intubation in an emergency department: A randomised clinical trial

BACKGROUND Airway management in the emergency room can be challenging when patients suffer from life-threatening conditions. Mental stress, ignorance of the patient's medical history, potential cervical injury or immobilisation and the presence of vomit and/or blood may also contribute to a difficult airway. Videolaryngoscopes have been introduced into clinical practice to visualise the airway and ultimately increase the success rate of airway management. OBJECTIVE The aim of this study was to test the hypothesis that the C-MAC videolaryngoscope improves first-attempt intubation success rate compared with direct laryngoscopy in patients undergoing emergency rapid sequence intubation in the emergency room setting. DESIGN A randomised clinical trial. SETTING Emergency Department of the University Hospital, Zurich, Switzerland. PATIENTS With approval of the local ethics committee, we prospectively enrolled 150 patients between 18 and 99 years of age requiring emergency rapid sequence intubation in the emergency room of the University Hospital Zurich. Patients were randomised (1 : 1) to undergo tracheal intubation using the C-MAC videolaryngoscope or by direct laryngoscopy. INTERVENTIONS Owing to ethical considerations, patients who had sustained maxillo-facial trauma, immobilised cervical spine, known difficult airway or ongoing cardiopulmonary resuscitation were excluded from our study. All intubations were performed by one of three very experienced anaesthesia consultants. MAIN OUTCOME MEASURES First-attempt success rate served as our primary outcome parameter. Secondary outcome parameters were time to intubation; total number of intubation attempts; Cormack and Lehane score; inadvertent oesophageal intubation; ease of intubation; complications including violations of the teeth, injury/bleeding of the larynx/pharynx and aspiration/regurgitation of gastric contents; necessity of using further alternative airway devices for successful intubation; maximum decrease of oxygen saturation and technical problems with the device. RESULTS A total of 150 patients were enrolled, but three patients had to be excluded from the analysis, resulting in 74 patients in the C-MAC videolaryngoscopy group and 73 patients in the direct laryngoscopy group. Tracheal intubation was achieved successfully at the first attempt in 73 of 74 patients in the C-MAC group and all patients in the direct laryngoscopy group (P = 1.0). Time to intubation was similar (32 ± 11 vs. 31 ± 9 s, P = 0.51) in both groups. Visualisation of the vocal cords, represented as the Cormack and Lehane score, was significantly better using the C-MAC videolaryngoscope (P < 0.001). CONCLUSION Our study demonstrates that visualisation of the vocal cords was improved by using the C-MAC videolaryngoscope compared with direct laryngoscopy. Better visualisation did not improve first-attempt success rate, which in turn was probably based on the high level of experience of the participating anaesthesia consultants. TRIAL REGISTRATION Clinicaltrials.gov identifier NCT02297113

Sense and Nonsense of an Extended Pelvic Lymph Node Dissection in Prostate Cancer

Lymph node metastases associated with prostate cancer (PCa) has been shown to be a poor prognostic factor. The role of pelvic lymph node dissection (PLND) itself in relation to survival remains unclear, however. A Medline search was conducted to address this issue. The following conclusions were drawn. Only recently, improved survival due to completion of radical prostatectomy (RP) (compared to abandoning RP) in known or presumed lymph-node-positive patients has been shown. Lymph node sampling can only be considered representative if an adequate number of nodes is removed. While several authors have suggested that a therapeutic benefit in patients undergoing RP is not provided by PLND, the reliability of these studies is uncertain. Contrary to this, several studies have indicated the possibility of long-term survival even in the presence of limited lymph node metastases. The role and timing of initiation of adjuvant androgen deprivation therapy (ADT) in patients who have node-positive disease after RP is controversial. Recent studies suggest that delaying ADT may not adversely impact survival

Engineering Students as Co-creators in an Ethics of Technology Course

Research on the effectiveness of case studies in teaching engineering ethics in higher education is underdeveloped. To add to our knowledge, we have systematically compared the outcomes of two case approaches to an undergraduate course on the ethics of technology: a detached approach using real-life cases and a challenge-based learning (CBL) approach with students and stakeholders acting as co-creators (CC). We first developed a practical typology of case-study approaches and subsequently tested an evaluation method to assess the students’ learning experiences (basic needs and motivation) and outcomes (competence development) and staff interpretations and operationalizations, seeking to answer three questions: (1) Do students in the CBL approach report higher basic needs, motivation and competence development compared to their peers in the detached approach? (2) What is the relationship between student-perceived co-creation and their basic needs, motivation and competence development? And (3) what are the implications of CBL/CC for engineering-ethics teaching and learning? Our mixed methods analysis favored CBL as it best supported teaching and research goals while satisfying the students’ basic needs and promoting intrinsic motivation and communication competences. Competence progress in other areas did not differ between approaches, and motivation in terms of identified regulation was lower for CBL, with staff perceiving a higher workload. We propose that our case typology model is useful and that as a method to engage students as co-creators, CBL certainly merits further development and evaluation, as does our effectiveness analysis for engineering ethics instruction in general and for case-study approaches in particular

Engineering Students as Co-creators in an Ethics of Technology Course

Research on the effectiveness of case studies in teaching engineering ethics in higher education is underdeveloped. To add to our knowledge, we have systematically compared the outcomes of two case approaches to an undergraduate course on the ethics of technology: a detached approach using real-life cases and a challenge-based learning (CBL) approach with students and stakeholders acting as co-creators (CC). We first developed a practical typology of case-study approaches and subsequently tested an evaluation method to assess the students’ learning experiences (basic needs and motivation) and outcomes (competence development) and staff interpretations and operationalizations, seeking to answer three questions: (1) Do students in the CBL approach report higher basic needs, motivation and competence development compared to their peers in the detached approach? (2) What is the relationship between student-perceived co-creation and their basic needs, motivation and competence development? And (3) what are the implications of CBL/CC for engineering-ethics teaching and learning? Our mixed methods analysis favored CBL as it best supported teaching and research goals while satisfying the students’ basic needs and promoting intrinsic motivation and communication competences. Competence progress in other areas did not differ between approaches, and motivation in terms of identified regulation was lower for CBL, with staff perceiving a higher workload. We propose that our case typology model is useful and that as a method to engage students as co-creators, CBL certainly merits further development and evaluation, as does our effectiveness analysis for engineering ethics instruction in general and for case-study approaches in particular

Can Technological Artefacts Be Moral Agents?

In this paper we discuss the hypothesis that, ‘moral agency is distributed over both humans and technological artefacts’, recently proposed by Peter-Paul Verbeek. We present some arguments for thinking that Verbeek is mistaken. We argue that artefacts such as bridges, word processors, or bombs can never be (part of) moral agents. After having discussed some possible responses, as well as a moderate view proposed by Illies and Meijers, we conclude that technological artefacts are neutral tools that are at most bearers of instrumental value