RESUMO
The nitrogen-vacancy (NV) centre in diamond is a promising candidate for quantum computing applications and magnetic sensing applications, because it is an atomic-scale defect with stable coherence time (T2) and reliable accessibility at room temperature. We demonstrated a method for improving the NV spin properties (the full width half maximum (FWHM) value of the magnetic resonance spectrum and T2) through a near-field (NF) etching method under ambient conditions. The NF etching method, based on a He-Cd ultraviolet laser (325 nm), which is longer than the absorption edge of the oxygen molecule, enabled selective removal of defects on the nanodiamond surface. We observed a decrease in the FWHM value close to 15% and an increase in T2 close to 25%. Since our technique can be easily reproduced, a wide range of NV centre applications could be improved, especially magnetic sensing applications. Our results are especially attractive, because they have been obtained under ambient conditions and only require a light source with wavelength slightly above the O2 absorption edge.
RESUMO
Many different approaches have been proposed for the challenging problem of visually analyzing large networks. Clustering is one of the most promising. In this paper, we propose a new clustering technique whose goal is that of producing both intracluster graphs and intercluster graph with desired topological properties. We formalize this concept in the (X,Y) -clustering framework, where Y is the class that defines the desired topological properties of intracluster graphs and X is the class that defines the desired topological properties of the intercluster graph. By exploiting this approach, hybrid visualization tools can effectively combine different node-link and matrix-based representations, allowing users to interactively explore the graph by expansion/contraction of clusters without loosing their mental map. As a proof of concept, we describe the system Visual Hybrid (X,Y)-clustering (VHYXY) that implements our approach and we present the results of case studies to the visual analysis of social networks.
RESUMO
INTRODUCTION: The growing importance of clinical research in Germany requires physicians who are adequately trained to conduct clinical trials. In November 2007, the Coordination Centre for Surgical Studies at the University of Munich organised its third course for clinical investigators. The course was evaluated by the participants. PARTICIPANTS AND PROGRAMME: Participants included 1st-year residents as well as specialists mostly from surgical departments; many already possessed significant experience with clinical trials. In our course, special emphasis was put on the practical aspects of conducting clinical trials. EVALUATION: On a scale from 1 to 6 (in German grading, 1 is the best score), participants rated content at 1.5, understanding at 1.6, and learning effect at 1.8. Careful preparation and a clearly structured curriculum resulted in significantly better evaluation of this course than of preceding courses (content P=0.015, understanding P=0.007, learning effect P=0.018). DISCUSSION: To realise projects of translational investigation and to participate in interdisciplinary clinical trials, surgeons in academic centres should obtain basic knowledge on clinical and pharmaceutical trials. Participants' statements on their own experience as clinical investigators underline the need for adequate training in this field. This course conveys essential knowledge of good medical practice and critical review of medical literature. We view this knowledge as a basic skill for modern medical practice and have therefore integrated the course into basic surgical training at our department. CONCLUSION: The concept of training for clinical investigation conducted at a surgical department is well established, and the participants' positive feedback motivates us to continue organising such courses.