135 research outputs found
Gravitational Wave Detection by Laser Interferometry on Earth
Abstract The existence of gravitational waves is the most prominent of Einstein's predictions that has not yet been directly verified. Worldwide, ground-based gravitational wave detectors using laser interferometry are being commissioned for science runs. The largest are the two US detectors of the LIGO project: facilities at widely separated sites in the states of Washington and Louisiana, each with 4 km armlength. LIGO data runs have shown the excellent reliability. Similarly encouraging results are reported from the British-German project GEO 600 with 600 m arms. The Japanese project TAMA 300 (with 300 m arms) was the earliest to exhibit good and reliable continuous runs. In all of these projects, the final level of sensitivity has yet to be attained. The French-Italian VIRGO project is to start using its 3 km interferometer by the end of this year. Future enhanced versions are being planned, with scientific data not expected until 2008. The sensitivities to be obtained will allow cosmic events of great scientific interest to be monitored. Detection of the events, and the quantitative analysis together with the location in the sky will provide vital information not obtainable via the window of electromagnetic radiation
Neural networks as a prognostic tool in critically ill patients
Im Zeitraum 1. 11. 1993 bis 30. 3. 1997 wurden 1149 allgemeinchirurgische Intensivpatienten prospektiv erfaßt, von denen 114 die Kriterien des septischen Schocks erfüllten. Die Letalität der Patienten mit einem septischen Schock betrug 47,3%. Nach Training eines neuronalen Netzes mit 91 (von insgesamt n = 114) Patienten ergab die Testung bei den verbleibenden 23 Patienten bei der Berücksichtigung von Parameterveränderungen vom 1. auf den 2. Tag des septischen Schocks folgendes Ergebnis: Alle 10 verstorbenen Patienten wurden korrekt als nicht überlebend vorhergesagt, von den 13 Überlebenden wurden 12 korrekt als überlebend vorhergesagt (Sensitivität 100%; Spezifität 92,3%).Neural networks as a prognostic tool in critically ill patients Summary: From 1. 11. 93 to 30. 3. 97, 1149 patients were prospectively studied during their ICU stay. Of them,114 met the criteria of septic shock, with lethality of 47.3%. A neural network was trained with datasets from 91 of these 114 patients. Testing the trained neural network with the remaining 23 patients, the following result was obtained: all 10 patients dying from septic shock were correctly predicted; of 13 surviving patients, 12 were correctly identified (sensitivity 100%; specifity 92.3%)
CIS: A Web-Based Course Information System
This report surveys the design and implementation of CIS, a web-based Course Information System. CIS has been developed for the Computer Science I/II courses held between 2000 and 2003 by Prof. Dr. R. Loos, which were attended by 300 to 450 students. It maintains and presents each student's submissions and grades and holds related information such as worksheet texts, submission deadlines and the assignment of students to teaching assistents. In short, it covers most of the administrative data that comes up in regular university courses.
CIS is designed to be used by first-year students conveniently. It aims at modelling real-world procedures, so that the system behaviour can be explained in well-known analogies. It is minimalistic, in the sense that it only takes on the routine work, while leaving the teacher free in any questions of structuring the contents of the course.
Our problem statement and analysis focuses to two aspects: The requirements on the central data base and the interfaces for three groups of users: Students, teaching assistants, and teachers/adminis-trators. The actual implementation is straightforward, and we only mention particular decisions taken herein.
CIS has been in use at the Wilhelm-Schickard Institut for three years, in courses organized both by the authors and others. The experiences indicate that the system can be considered reliable and mature. As the effort of setting up CIS is small, it has become feasible to employ it for several advanced courses with fewer than 20 students
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Free-standing millimetre-long Bi2Te3 sub-micron belts catalyzed by TiO2 nanoparticles
Physical vapour deposition (PVD) is used to grow millimetre-long Bi2Te3 sub-micron belts catalysed by TiO2 nanoparticles. The catalytic efficiency of TiO2 nanoparticles for the nanostructure growth is compared with the catalyst-free growth employing scanning electron microscopy. The catalyst-coated and catalyst-free substrates are arranged side-by-side, and overgrown at the same time, to assure identical growth conditions in the PVD furnace. It is found that the catalyst enhances the yield of the belts. Very long belts were achieved with a growth rate of 28 nm/min. A ∼1-mm-long belt with a rectangular cross section was obtained after 8 h of growth. The thickness and width were determined by atomic force microscopy, and their ratio is ∼1:10. The chemical composition was determined to be stoichiometric Bi2Te3 using energy-dispersive X-ray spectroscopy. Temperature-dependent conductivity measurements show a characteristic increase of the conductivity at low temperatures. The room temperature conductivity of 0.20 × 10(5) S m (-1) indicates an excellent sample quality
Synthetic biology – The next phase of biotechnology and genetic engineering. Summary
For a good ten years now, the term "synthetic biology" (Synbio for short) has been used to describe research projects, methods and procedures for a "transformation" of natural organisms that goes further than was previously possible with the help of genetic engineering. The creation of (completely) artificial "biological" systems (synbio in the narrow sense) is envisaged, although their practical use is still a long way off and is therefore unlikely to have much social and political relevance in the coming years. The situation is quite different with synbio in the broader sense - understood as the next stage of biotechnology and genetic engineering, which includes in particular the recently developed methods of so-called genome editing (including CRISPR/Cas). Due to the increasingly simple and faster possibilities of targeted molecular biological modification of known organisms, a large number of applications in microorganisms, plants and animals can be expected in the coming years. As expected, the debate on the responsible use and necessary regulation of genetic engineering gained momentum in autumn 2015. The TAB report provides a comprehensive account of the state of research, development and application, safety and governance issues of synbio, as well as a detailed portrait of actors and perspectives of do-it-yourself biology. It places the debates on the potentials and perspectives of synbio in larger science, research and innovation policy contexts and elaborates central questions for the future and fields of action - including in the area of biosafety research and with a view to expanding the groups of actors in the planning and implementation of research programmes and projects
Funktionalisierte Kohlenstoffnanoröhren: Materialforschung in der Nanowelt
Thanks to their extraordinary properties, carbon nanotubes reveal a promising potential for applications on the nanometre scale. When filled with metals or ferromagnets, nano-wires and magnets with a protecting carbon shell are realised. Different synthesis routes are described, such as laser ablation and chemical vapour deposition. Probes for magnetic force microscopy based on ironfilled carbon nanotubes are presented, and demonstrate a high spatial resolution, with the carbon shells at the same time providing effective wear resistance. We show also the potential of carbon nanotubes for biomedical applications, in particular their suitability as magnetic nano-heaters, drug-carrier systems or sensors for diagnostic and therapeutic usage on the cellular level.Außergewöhnliche Materialeigenschaften machen Kohlenstoffnanoröhren zu einem vielseitigen nanoskaligen Werkstoff. Füllt man sie zum Beispiel mit metallischen oder ferromagnetischen Materialien, so ergeben sich durch eine Kohlenstoffhülle geschützte „Nano- Kabel“ oder Nano-Magnete. Neben verschiedenen Syntheseverfahren wie der Laserablation und der Chemischen Gasphasenabscheidung werden grundlegende physikalische Eigenschaften sowie Anwendungen in der Messtechnik und in der Medizin vorgestellt. In der Magnetkraftmikroskopie versprechen magnetisch gefüllte Kohlenstoffnanoröhren eine hohe laterale Auflösung bei gleichzeitigem Schutz des magnetischen Messsensors durch die Außenhülle. Im Bereich der biomedizinischen Anwendungen stellen Kohlenstoffnanoröhren ein nanoskaliges Transportmedium dar, das zum Transfer von Funktionsmaterialien in einzelne Zellen, zum Beispiel für magnetische Sensorik oder für Medikamententransporte, angewendet werden kann
Aspekte der Sauerstoffversorgung bei Verwesungsprozessen im Unterboden
Mittels eines Sauerstoff zehrenden Prozesses wurde in Säulenversuchen der Einfluss des Bodens auf Verwesungsprozesse im Unterboden untersucht. Aus den gewonnenen Daten wurden Modelle zur Prognose der Verwesungszeiten und der Sauerstoffkonzentrationen im Tiefenprofil von Böden erstellt
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