81 research outputs found
Implantation of paclitaxel-eluting stents in saphenous vein grafts: clinical and angiographic follow-up results from a multicentre study.
Objective: To define the clinical and angiographic follow-up results after implantation of paclitaxel-eluting stents (PESs) in stenotic saphenous vein grafts (SVGs).
Design: Prospective multicentre study. Comparison with a control group.
Methods: 60 consecutive patients with 65 lesions located in 65 SVGs (mean (SD) age of vein grafts 11.3 (5.7) years) treated with PES (V-Flex Plus, 2.7 mg/mm2 paclitaxel, Cook) and 60 patients with 60 SVG lesions treated with bare metal stent (BMS) were included. Lesions had to be ,20 mm in length and in grafts of 2.75–3.5 mm diameter. The 6 month angiographic follow-up was obtained on 51 lesions (79%) of the PES group and on 51 lesions (85%) of the BMS group.
Results: Baseline clinical and angiographic characteristics were comparable between both groups. At angiographic follow-up, three vein grafts in the PES group and five vein grafts in the BMS group were occluded. In-stent late lumen loss was lower in PES than in BMS (0.61 (0.81) vs 1.06 (0.72) mm, respectively; p = 0.021). In-stent binary restenosis rates were 12% vs 33%, respectively, (p = 0.012). Linear regression analysis showed BMS to be the only factor with an effect on late lumen loss (p = 0.011). Target-vessel failure rates were 18% in the PES group and 41% in the BMS group (p = 0.019), whereas major adverse cardiac event (MACE) rates at 180 days were 15% and 37%, respectively (p = 0.014).
Conclusions: Implantation of non-polymer-based PES in SVG lesions is associated with a lower late lumen loss and restenosis rate than those of BMS. There remains a substantial target-vessel failure rate and MACE rate even at 6 months owing to graft occlusion or new lesions in the graft
Early Computer Science Education. Goals and Success Criteria for Pre-Primary and Primary Education
“Scientific Studies on the Work of the ‘Haus der kleinen Forscher’ Foundation” is a regularly published series of scientific reports authored by distinguished experts from the field of early education. This series serves to pursue professional dialogue between the Foundation, academia and practice, with the aim of lending sound support to all child-care centres, after-school care centres and primary schools in Germany in their educational mission. This ninth volume of the series, with a foreword by Ilan Chabay, deals with the goals and requirements of computer science education in the elementary and primary sector. In their expert report, Nadine Bergner, Hilde Köster, Johannes Magenheim, Kathrin Müller, Ralf Romeike, Ulrik Schroeder and Carsten Schulte specify the pedagogical and content-related goal dimensions of computer science education at child-care centres and primary schools. In addition to establishing a theoretical basis for various goal dimensions, the authors discuss the success criteria for effective and efficient early computer science education in practice. They also provide recommendations for the further development of the Foundation’s offerings and scientific accompaniment of the work of the Foundation in the field of computer science. In their expert recommendation, Nadine Bergner and Kathrin Müller describe a selection of informatics systems for children at child-care centres and primary schools and offer suggestions for particularly suitable systems and their use in elementary and primary education based on professional criteria. The final chapter of the volume describes the implementation of these professional recommendations in the programmes of the “Haus der kleinen Forscher” Foundation – with and without computers. (DIPF/Verlag
Genetic diversity in terrestrial subsurface ecosystems impacted by geological degassing
Earth’s mantle releases 38.7 ± 2.9 Tg/yr CO2 along with other reduced and oxidized gases to the atmosphere shaping microbial metabolism at volcanic sites across the globe, yet little is known about its impact on microbial life under non-thermal conditions. Here, we perform comparative metagenomics coupled to geochemical measurements of deep subsurface fluids from a cold-water geyser driven by mantle degassing. Key organisms belonging to uncultivated Candidatus Altiarchaeum show a global biogeographic pattern and site-specific adaptations shaped by gene loss and inter-kingdom horizontal gene transfer. Comparison of the geyser community to 16 other publicly available deep subsurface sites demonstrate a conservation of chemolithoautotrophic metabolism across sites. In silico replication measures suggest a linear relationship of bacterial replication with ecosystems depth with the exception of impacted sites, which show near surface characteristics. Our results suggest that subsurface ecosystems affected by geological degassing are hotspots for microbial life in the deep biosphere
Influence of Ocean Acidification on a Natural Winter-to-Summer Plankton Succession : First Insights from a Long-Term Mesocosm Study Draw Attention to Periods of Low Nutrient Concentrations
Every year, the oceans absorb about 30% of anthropogenic carbon dioxide (CO2) leading to a re-equilibration of the marine carbonate system and decreasing seawater pH. Today, there is increasing awareness that these changes-summarized by the term ocean acidification (OA)-could differentially affect the competitive ability of marine organisms, thereby provoking a restructuring of marine ecosystems and biogeochemical element cycles. In winter 2013, we deployed ten pelagic mesocosms in the Gullmar Fjord at the Swedish west coast in order to study the effect of OA on plankton ecology and biogeochemistry under close to natural conditions. Five of the ten mesocosms were left unperturbed and served as controls (similar to 380 mu atm pCO(2)), whereas the others were enriched with CO2-saturated water to simulate realistic end-of-the-century carbonate chemistry conditions (mu 760 mu atm pCO(2)). We ran the experiment for 113 days which allowed us to study the influence of high CO2 on an entire winter-to-summer plankton succession and to investigate the potential of some plankton organisms for evolutionary adaptation to OA in their natural environment. This paper is the first in a PLOS collection and provides a detailed overview on the experimental design, important events, and the key complexities of such a "long-term mesocosm" approach. Furthermore, we analyzed whether simulated end-of-the-century carbonate chemistry conditions could lead to a significant restructuring of the plankton community in the course of the succession. At the level of detail analyzed in this overview paper we found that CO2-induced differences in plankton community composition were non-detectable during most of the succession except for a period where a phytoplankton bloom was fueled by remineralized nutrients. These results indicate: (1) Long-term studies with pelagic ecosystems are necessary to uncover OA-sensitive stages of succession. (2) Plankton communities fueled by regenerated nutrients may be more responsive to changing carbonate chemistry than those having access to high inorganic nutrient concentrations and may deserve particular attention in future studies.Peer reviewe
3. Vortrag (30.03.2006): Telekolloquium - Öffentliche Ringvorlesungen als Mehrpunktkonferenz zwischen norddeutschen Hochschulen
Inhalt:
Zielsetzung; Methode; Ausblic
Early Detection of Hazards in Driving Situations through Multi-Sensor Fusion
This article proposes a novel approach for detecting hazardous events in driving situations. The assessment of hazards is based on the detection of atypical situations. The main assumption is that driving situations might get dangerous when an implicit normal state is not given any more. A prototype for the detection of atypical driving situations has been developed. In a first step, a multi-sensor multi-level fusion framework is presented and exemplified by object detection based on a camera and a laser scanner. The detected objects with their specific behaviours are transformed into a Statistical Information Grid (SIG), which is filled up with training information. In the working phase, current situations are compared to the statistical information and declared as atypical if under a given threshold. The prototype has been implemented. It has been shown that the recognition of atypical driving events is possible in selected driving situations
Image and Laser Scanner Processing as Confident Cues for Object Detection in Driving Situations
In the area of advanced driver assistance and automation systems knowledge about the vehicle environment is becoming more and more important in order to increase traffic safety. This paper is concerned with the detection and tracking of objects in the proximity of the ego-vehicle while driving on highways. For this purpose, a camera sensor and a laser scanner are used. The processed data of the sensors is then fused at object level in a competitive way. The paper focuses on the generation of object observations by applying the mentioned sensors. In the case of the camera system, an image processing method based on texture information is presented. The texture information is adaptively calculated in order to be independent of the lighting conditions. Taking into account knowledge about the image structure in driving situations, texture segments are classified and object observations are generated. In comparison to other methods, objects are detected independently of any features, model and movement assumptions. For object generation from laser scanner data, a method characterizing detected object contours by means of a shape indicator (long, corner, round, concave etc.) is proposed. Different to other works in this field, in the method presented here explicitly obtains the objects’ optimal reference point and the observability of the objects’ components. The experiments conducted both with simulated and real data show the plausibility of the methods to be used as cues for an object fusion system
Objektverfolgung und -fusion für die Ableitung von Fahrsituationen
Um die Entwicklung leistungsfähiger Fahrerassistenz- und Automationssysteme zu ermöglichen, ist eine detaillierte Beschreibung der Fahrsituation wesentlich. Dieser Beitrag beschäftigt sich mit der Erkennung von 3D-Objekten und insbesondere mit derer Verfolgung. Hierzu werden neue Strategien zur Behandlung typischer Problemen und Inkonsistenzen in der Objektverfolgung und -fusion vorgestellt, wie beispielsweise unsichere Daten, Daten bei veränderlicher Perspektive, Ausreißer, Split- und Merge-Effekte etc. Die vorgeschlagenen Mechanismen reichen von der adaptiven Modellierung des Rauschens, über die mehrfache Assoziation, die Verdoppelung bzw. Vereinigung von Objekthypothesen bis hin zur expliziten Modellierung der partiellen Beobachtbarkeit der Objekte. Diese Strategien wurden anhand von simulierten und realen Daten getestet. Die Ergebnisse zeigen eine deutliche Verbesserung der Objektqualität bei vergleichsweise schlanken und effektiven Mechanismen
Sensorfusion für die Beschreibung der Fahrsituation mit Daten des Versuchsfahrzeugs ViewCar
Dieser Beitrag stellt ein Sensorfusionssystem zur Erkennung und Bewertung der Fahrumge-bung eines Straßenfahrzeugs vor. Die zentralen Entwurfsentscheidungen zum Aufbau des Sensorfusionssystems werden eingeführt und am Beispiel der Objekterkennung auf Grund-lage der Daten eines Laserscanners und einer Kamera vertiefend diskutiert. Das Fusionssys-tem besteht aus drei aufeinander aufbauenden Verarbeitungsebenen. In einer sensornahen Ebene (low-level) werden die Bilder vorverarbeitet (Bildverbesserung) und der Fahrkorridor anhand der Laserscannerdaten erkannt. In der Objektebene (middle-level) werden Objekt-hypothesen anhand einzelner Sensoren erzeugt und fusioniert. Für die Kamera werden Bildmerkmale wie Konturen, Straßentextur und markante Eckpunkte verwendet. Schließlich wird in der abstrakten Ebene (high-level) zukünftig eine Gefahrenerkennung erfolgen. Das Sensorfusionssystem ist modular aufgebaut und deshalb flexibel anpassbar und erweiterbar
Devonian carbonates of the Nigel Peak area, Rocky Mountains, Canada: A fossil petroleum system ?
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