44 research outputs found
Research in medical education - chances and challenges : international conference, 20th - 22nd May 2009, Heidelberg ; congress abstracts
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OPM magnetorelaxometry in the presence of a DC bias field
No full textSpatial quantitative information about magnetic nanoparticle (MNP) distributions is a prerequisite for biomedical applications like magnetic hyperthermia and magnetic drug targeting. This information can be gathered by means of magnetorelaxometry (MRX) imaging, where the relaxation of previously aligned MNP’s magnetic moments is measured by sensitive magnetometers and an inverse problem is solved. To remove or minimize the magnetic shielding in which MRX imaging is carried out today, the knowledge of the influence of background magnetic fields on the MNP’s relaxation is a prerequisite. We show MRX measurements using an intensity-modulated optically pumped magnetometer (OPM) in background magnetic fields of up to 100μT. We show that the relaxation parameters alter or may be intentionally altered significantly by applying static fields parallel or antiparallel to the MNP’s alignment direction. Further, not only the relaxation process of the MNP’s magnetic moments could be measured with OPM, but also their alignment due to the MRX excitation field. © 2020, The Author(s)
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Successful optimization of reconstruction parameters in structured illumination microscopy
No full textThe impact of the different reconstruction parameters in super-resolution structured illumination microscopy (SIM) on image artifacts is carefully analyzed. These parameters comprise the Wiener filter parameter, an apodization function, zero-frequency suppression and modifications of the optical transfer function. A detailed investigation of the reconstructed image spectrum is concluded to be suitable for identifying artifacts. For this purpose, two samples, an artificial test slide and a more realistic biological system, were used to characterize the artifact classes and their correlation with the image spectra as well as the reconstruction parameters. In addition, a guideline for efficient parameter optimization is suggested and the implementation of the parameters in selected up-to-date processing packages (proprietary and open-source) is depicted. © 2018 The Author
Author Correction: Comprehensive analysis of chromothripsis in 2,658 human cancers using whole-genome sequencing
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Planning the Bothnian Sea
No full textIn all parts of the world the sea is a source of life, of energy, of food, of commerce, of fun. Its water, wind, and waves are all in demand – as a playground for pleasure-seekers and nature-lovers, as a highway for international commerce, as a home for unique communities of wildlife and people. All this is also true for the Bothnian Sea, a part of the northern European Baltic Sea between Finland and Sweden.
The Bothnian Sea is used by two neighbouring highly developed societies. There are many demands on its resources, and its open spaces are highly coveted areas for developments such as wind power farms. This relatively sparsely habitated corner of the world is also, at least at times, a place of wild seas and ancient heritage.
Like planning on land, maritime spatial planning is a process that has to incorporate ideals of the public good and the various politically-anchored ways to define this, taking in to account private development interests as well as the physical realities of limited natural resources and fragile ecosystems.
This book provides an introduction to the Bothnian Sea and the ideas around maritime spatial planning for its offshore areas. We have tried to present a balance between the perspectives of competing interests. As this has been a pilot initiative, we have not aimed to give you ready answers, but instead try to provoke further debate. The Bothnian Sea and its future are in your hands.
The edito
Community-based social services: practical advice based upon lessons from outside the World Bank
No full textThe purpose of this paper is to gather information in both developed and developing countries, on design and delivery of community based social service initiatives. While the field is sufficiently new that best practice may not yet be fully identifiable, there are many initiatives funded by other governments, NGOs, and donor agencies, which taken along with acknowledged good practice from the industrialized world, can help task managers with the design of community-based social service projects.Street Children,Adolescent Health,Health Monitoring&Evaluation,Banks&BankingReform,Civil Society
Compensation effects in GaN:Mg probed by Raman spectroscopy and photoluminescence measurements
No full textThis article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This article appeared in J. Appl. Phys. 113, 103504 (2013) and may be found at https://doi.org/10.1063/1.4794094.Compensation effects in metal organic chemical vapour deposition grown GaN doped with magnesium are investigated with Raman spectroscopy and photoluminescence measurements. Examining the strain sensitive E2(high) mode, an increasing compressive strain is revealed for samples with Mg-concentrations lower than 7 × 1018 cm−3. For higher Mg-concentrations, this strain is monotonically reduced. This relaxation is accompanied by a sudden decrease in crystal quality. Luminescence measurements reveal a well defined near band edge luminescence with free, donor bound, and acceptor bound excitons as well as a characteristic donor acceptor pair (DAP) luminescence. Following recent results, three acceptor bound excitons and donor acceptor pairs are identified. Along with the change of the strain, a strong modification in the luminescence of the dominating acceptor bound exciton and DAP luminescence is observed. The results from Raman spectroscopy and luminescence measurements are interpreted as fingerprints of compensation effects in GaN:Mg leading to the conclusion that compensation due to defect incorporation triggered by Mg-doping already affects the crystal properties at doping levels of around 7 × 1018 cm−3. Thereby, the generation of nitrogen vacancies is introduced as the driving force for the change of the strain state and the near band edge luminescence.DFG, 43659573, SFB 787: Halbleiter - Nanophotonik: Materialien, Modelle, Bauelement
Lithium related deep and shallow acceptors in Li-doped ZnO nanocrystals
No full textThis article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This article appeared in Journal of Applied Physics 107, 024311 (2010) and may be found at https://doi.org/10.1063/1.3275889.We study the existence of Li-related shallow and deep acceptor levels in Li-doped ZnO nanocrystals using electron paramagnetic resonance (EPR) and photoluminescence (PL) spectroscopy. ZnO nanocrystals with adjustable Li concentrations between 0% and 12% have been prepared using organometallic precursors and show a significant lowering of the Fermi energy upon doping. The deep Li acceptor with an acceptor energy of 800 meV could be identified in both EPR and PL measurements and is responsible for the yellow luminescence at 2.2 eV. Additionally, a shallow acceptor state at 150 meV above the valence band maximum is made responsible for the observed donor-acceptor pair and free electron-acceptor transitions at 3.235 and 3.301 eV, possibly stemming from the formation of Li-related defect complexes acting as acceptors.DFG, 43659573, SFB 787: Halbleiter - Nanophotonik: Materialien, Modelle, Bauelement
Telling your story: autobiographical metadata and the semantic web
No full textGiven the current explosion of user-generated content driven by the ever-decreasing price of sensing and storage hardware the dream of capturing and archiving the entirety of a human life is slowly being realised. The Semantic Web, a discipline of Computer Science, aims to support the sharing and interoperation of knowledge using the Web’s infrastructure. This thesis aims to roadmap a framework utilising the principles and technologies underpinning the Semantic Web, enabling the vision of global knowledge sharing, in an open and policy aware manner, with the end aim of supporting a network for the exploitation of personal information. This sharing is facilitated through the adoption of a lingua franca, shared conceptualisations for domain knowledge, and some core design principles. The main focus of Semantic Web research has been the development of a web-scale knowledge-base whereby information is stored and exposed in a machine-readable format with the ultimate aim of aggregating information from disparate sources, allowing for statements to be contextualised with respect to others culminating in a web-scale knowledge resource accessible through standard protocols.The current popularity of social computing – Web 2.0 – where users post personal information to online communities is eluding to the fact that information, linked and shared within a social-context presents added value to the end-user. Given the sensitive nature of personal information, one may not wish to expose all of the information about them self to the World Wide Web, but may wish to benefit by linking to knowledge residing on this shared resource. This ability to store personal information privately, in ones own personal web-space and not on a third party server, whilst at the same time connecting to the publicly available information is presented as key challenge facing the Computer Science community today. Specific information pertaining to one aspect of a user’s activities, such as their picture taking habits or their geographic log, may not present a detailed account of a user’s actions, but as more information is pushed into the public domain and aggregation technologies mature individuals and their day-to-day activities will be easier to track. As more and more of our personal lives are pushed into the public domain, the notion of an online-persona is becoming more and more applicable to the average person.This thesis presents an infrastructure for the capturing and archival of autobiographical metadata, whereby information from multiple sensors is aggregated and stored in a personal Lifelog. The surrender of digital identity has become commonplace, for purposes ranging from commerce, marketing, social networking, government, receipt of services, travel or security, Lifelogging has the potential to reaffirm the individual’s control of his or her own digital identity. The Lifelog is a constructed identity that outweighs the others simply by weight of evidence, complexity and comprehensiveness. This thesis presents an infrastructure for the capture and exploitation of personal metadata to drive research into context aware systems. The aim is to expose ongoing research in the areas of capture of personal experiences, context aware systems, multimedia annotation systems, narrative generation, all set in the context of enabling and supporting the Semantic Web Vision. The thesis details the work underway towards the goal of creating a multi-domain contextual log, and is followed by a discussion of how such a log can be used to drive the development of detailed Lifelog and an investigation into the amount of personal information being pushed into the public domain.<br/
