1,806 research outputs found
Influence of point defects on magnetic vortex structures
We employed micro-Hall magnetometry and micromagnetic simulations to
investigate magnetic vortex pinning at single point defects in individual
submicron-sized permalloy disks. Small ferromagnetic particles containing
artificial point defects can be fabricated by using an image reversal electron
beam lithography process. Corresponding micromagnetic calculations, modeling
the defects within the disks as holes, give reasonable agreement between
experimental and simulated pinning and depinning field values
Strongly birefringent cut-wire pair structure as negative index wave plates at THz frequencies
We report a new approach for the design and fabrication of thin wave plates
with high transmission in the terahertz (THz) regime. The wave plates are based
on strongly birefringent cut-wire pair metamaterials that exhibit refractive
indices of opposite signs for two orthogonal polarization components of an
incident wave. As specific examples, we fabricated and investigated a quarter-
and a half-wave plate that revealed a peak intensity transmittance of 74% and
58% at 1.34 THz and 1.3 THz, respectively. Furthermore, the half wave plate
displayed a maximum figure of merit (FOM) of 23 at 1.3 THz where the refractive
index was -1.7. This corresponds to one of the highest FOMs reported at THz
frequencies so far. The presented results evidence that negative index
materials enter an application stage in terms of optical components for the THz
technology.Comment: 4 pages, 3 figures, submitted to Appl. Phys. Let
A Grid Middleware for Ontology Access
Many advanced grid applications need access to ontologies represent-ing knowledge about a certain application domain. To deal with the high heterogeneity of available ontologies, we propose a general ser-vice-oriented middleware for making ontologies accessible to grid ap-plications. Our implementation is integrated in the German D-Grid in-frastructure and provides several applications a uniform access to biomedical ontologies such as Gene Ontology, NCI Thesaurus and several OBO ontologies
Metamaterial near-field sensor for deep-subwavelength thickness measurements and sensitive refractometry in the terahertz frequency range
We present a metamaterial-based terahertz (THz) sensor for thickness
measurements of subwavelength-thin materials and refractometry of liquids and
liquid mixtures. The sensor operates in reflection geometry and exploits the
frequency shift of a sharp Fano resonance minimum in the presence of dielectric
materials. We obtained a minimum thickness resolution of 12.5 nm (1/16000 times
the wavelength of the THz radiation) and a refractive index sensitivity of 0.43
THz per refractive index unit. We support the experimental results by an
analytical model that describes the dependence of the resonance frequency on
the sample material thickness and the refractive index.Comment: 10 pages, 5 figure
Distributed Holistic Clustering on Linked Data
Link discovery is an active field of research to support data integration in
the Web of Data. Due to the huge size and number of available data sources,
efficient and effective link discovery is a very challenging task. Common
pairwise link discovery approaches do not scale to many sources with very large
entity sets. We here propose a distributed holistic approach to link many data
sources based on a clustering of entities that represent the same real-world
object. Our clustering approach provides a compact and fused representation of
entities, and can identify errors in existing links as well as many new links.
We support a distributed execution of the clustering approach to achieve faster
execution times and scalability for large real-world data sets. We provide a
novel gold standard for multi-source clustering, and evaluate our methods with
respect to effectiveness and efficiency for large data sets from the geographic
and music domains
Transformation bending device emulated by graded-index waveguide
We demonstrate that a transformation device can be emulated using a
gradient-index waveguide. The effective index of the waveguide is spatially
varied by tailoring a gradient thickness dielectric waveguide. Based on this
technology, we demonstrate a transformation device guiding visible light around
a sharp corner, with low scattering loss and reflection loss. The experimental
results are in good agreement with the numerical results.Comment: This paper is published at Optics Express 20, 13006 (2012
Implementing universal Lynch syndrome screening (IMPULSS): protocol for a multi-site study to identify strategies to implement, adapt, and sustain genomic medicine programs in different organizational contexts
BACKGROUND: Systematic screening of all colorectal tumors for Lynch Syndrome (LS) has been recommended since 2009. Currently, implementation of LS screening in healthcare systems remains variable, likely because LS screening involves the complex coordination of multiple departments and individuals across the healthcare system. Our specific aims are to (1) describe variation in LS screening implementation across multiple healthcare systems; (2) identify conditions associated with both practice variation and optimal implementation; (3) determine the relative effectiveness, efficiency, and costs of different LS screening protocols by healthcare system; and (4) develop and test in a real-world setting an organizational toolkit for LS screening program implementation and improvement. This toolkit will promote effective implementation of LS screening in various complex health systems.
METHODS: This study includes eight healthcare systems with 22 clinical sites at varied stages of implementing LS screening programs. Guided by the Consolidated Framework for Implementation Research (CFIR), we will conduct in-depth semi-structured interviews with patients and organizational stakeholders and perform economic evaluation of site-specific implementation costs. These processes will result in a comprehensive cross-case analysis of different organizational contexts. We will utilize qualitative data analysis and configurational comparative methodology to identify facilitators and barriers at the organizational level that are minimally sufficient and necessary for optimal LS screening implementation.
DISCUSSION: The overarching goal of this project is to combine our data with theories and tools from implementation science to create an organizational toolkit to facilitate implementation of LS screening in various real-world settings. Our organizational toolkit will account for issues of complex coordination of care involving multiple stakeholders to enhance implementation, sustainability, and ongoing improvement of evidence-based LS screening programs. Successful implementation of such programs will ultimately reduce suffering of patients and their family members from preventable cancers, decrease waste in healthcare system costs, and inform strategies to facilitate the promise of precision medicine.
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