1,169 research outputs found
Reflection of waveguided X-rays in two-dimensional nanostructures
No full textThe internal reflection of an excited X-ray waveguide mode in a synthetic nanostructure, defined by electron-beam lithography, has been measured. In this device, the X-ray beam is first coupled into a conventional vertical thin-film waveguide structure and then reflected laterally at the quasi-one-dimensional edge of the waveguiding layer. The reflectivity of the quasi-one-dimensional interface has been recorded under simultaneous excitation of the (vertical) waveguide mode. The experiment constitutes an important step towards the production of a coherent nanometre-sized X-ray point source by two-dimensionally defined waveguide structures.</jats:p
Waveguide-enhanced scattering from thin biomolecular films
No full textAn X-ray diffraction experiment on multilamellar membranes incorporated into an X-ray waveguide structure is reported. In the device, the lipid bilayers are confined to one side by the silicon substrate and to the other side by an evaporated thin metal cap layer. Shining a highly brilliant X-ray beam onto the system, resonantly enhanced, precisely defined and clearly distinguishable standing-wavefield distributions (modes) are excited. The in-plane structure of the acyl chain ordering is then studied by grazing incidence diffraction under simultaneously excited modes. A significant gain in signal-to-noise ratio as well as enhanced spatial resolution can be obtained with such a setup
Managing Technology Risks Through Technological Proficiency: Guidance for Local Governments
No full textLike most organizations, local governments face challenges managing technology, the critical resource to meet evolving public service expectations. But benefits associated with adapting the latest technology come with risks, some more apparent than others.
This report details the problems facing municipal officials as they try to maximize the benefits of technology for their communities and constituents in the face of cybersecurity, legal, operational, financial, reputational and societal risks.
The report concludes that top municipal officials must create and maintain an environment of “technological proficiency.” That includes creating a process for making technology decisions, developing an annually reviewed technology plan that is tied to the budget, instituting a “cyber hygiene” training program for all employees in proper computer security practices, and making sure that agency technology is competently managed.
The report is supplemented by a "Best Practices and Resources Guide" that organizations can use to achieve technology proficiency. It provides best practices based on an organization's technology profile.Report and Supplement were prepared for the Municipal Excess Liability Fund, a joint insurance fund of over 600 New Jersey local government agencies
1D and 2D X-ray waveguides: Optics and applications
No full textX-ray waveguides [1-4] offer a novel approach for nanobeam production, which may become useful in
coherent beam imaging and phase contrast projection microscopy [5]. Internal field enhancement, coherency
properties, and coupling efficiency of these devices have been measured and compared to theoretic predictions. The
fundamentals of x-ray wave guide optics can be derived from a scalar wave equation. Up to now, x-ray waveguide
optics have exclusively been one-dimensional (1D), while many applications demand two-dimensionally (2D) confined
point beams. We have recently demonstrated the first proof of principle that x-ray waveguide effects can be generalized
to 2D devices using e-beam defined lithographic nanostructures [6], delivering of a coherent hard x-ray beam with
nanometer sized cross-section (69 nm 33 nm)
Two-dimensional x-ray waveguides and point sources
No full textWe show that resonant coupling of synchrotron beams into suitable nanostructures can be used for the generation of coherent x-ray point sources. A two-dimensionally con ning x-ray waveguide structure has been fabricated by e-beam lithography. By shining a parallel undulator beam onto the structure, a discrete set of resonant modes can be excited in the dielectric cavity, depending on the two orthogonal coupling angles between the beam and the waveguide interfaces. The resonant excitation of the modes is evidenced from the characteristic set of coupling angles as well as the observed far-field pattern. The x-ray nanostructure may be used as coherent x-ray point sources with a beam cross section in the nanometer range
Time-patterns of annualized relapse rates in randomized placebo-controlled clinical trials in relapsing multiple sclerosis: A systematic review and meta-analysis
No full textBackground: Although it is known that the annualized relapse rate (ARR) in patients with multiple sclerosis (MS) changes as disease progresses, in the design and analysis of trials in relapsing multiple sclerosis (RMS) constant ARRs are assumed. Objectives: This paper aims to assess time-patterns of trial ARR by conducting a systematic review of randomized, placebo-controlled trials in RMS. Methods: A systematic literature search was conducted by searching PubMed for randomized, placebo-controlled trials in RMS. In meta-analyses the following comparisons of trial ARR were carried out for the placebo controls and active treatment arms: months 1-6 vs. months 7-12, and months 1-12 vs. months 13-24. Results: A total of 52 trials was identified. Out of these, information on the time-dependence of trial ARR could be extracted from 13 trials. The ARR was by 25% (p = 0.0005) and 40% (p < 0.0001) higher in months 1-12 compared with months 13-24 for placebo and active treatments, respectively. Consequently, the treatment effects were by 13% (p = 0.23) larger in the second year compared with the first year. Within the first year of follow-up the ARR was by 4% (p = 0.75) and 23% (p = 0.06) higher in months 1-6 compared with months 7-12 for placebo controls and active arms, respectively. Conclusions: Trial ARR decreases during a trial in RMS, which is in line with epidemiological findings and has implications for design and analysis of future trials. The observed decrease in trial ARR might be at least partially explained by regression to the mean. Individual patient data analyses are warranted
Why people with disabilities might really be leaving work : an exemplar case with lessons for managers
No full textThe author explores the 'silent' problem of unseen illness at work
White beam x-ray waveguide optics
No full textWe report a white beam x-ray waveguide (WG) experiment. A resonant beam coupler x-ray waveguide (RBC) is used simultaneously as a broad bandpass (or multibandpass) monochromator and as a beam compressor. We show that, depending on the geometrical properties of the WG, the exiting beam consists of a defined number of wavelengths which can be shifted by changing the angle of incidence of the white x-ray synchrotron beam. The characteristic far-field pattern is recorded as a function of exit angle and energy. This x-ray optical setup may be used to enhance the intensity of coherent x-ray WG beams since the full energetic acceptance of the WG mode is transmitted. (C) 2004 American Institute of Physics
sj-docx-1-spo-10.1177_17479541231203497 - Supplemental material for Interest as a supplementary criterion in the detection of talent: The identification of differing types of children at primary school age
No full textSupplemental material, sj-docx-1-spo-10.1177_17479541231203497 for Interest as a supplementary criterion in the detection of talent: The identification of differing types of children at primary school age by Fabienne Spies, Larissa Heger, Tim Bindel and Mark Pfeiffer in International Journal of Sports Science & Coaching</p
>
No full textPlanar x-ray waveguide structures can be used as resonant beam coupling devices to produce a coherent and divergent x-ray line source with cross-sections in the sub-micrometer range. This article reviews the basic x-ray optical properties of such devices and generalizes the principle of resonant x-ray beam coupling to waveguides containing multiple guiding layers. In such a device, several coherent beams of a width on the order of 100 angstrom to 1000 angstrom can be extracted at the end of the waveguide. Besides coherent diffraction and imaging, interferometry with two or more nanometer sized beams can be envisioned. Furthermore this article presents measurements of the internal reflection of an excited x-ray waveguide mode in a synthetic nanostructure defined by e-beam lithography. In this device the x-ray beam is first coupled into a conventional vertical thin film waveguide structure and then reflected laterally at the quasi one-dimensional edge of the waveguiding layer. The reflectivity of the quasi one- dimensional interface has been recorded under simultaneous excitation of the (vertical) waveguide mode. This experiment constitutes an important step towards the production of a coherent, nanometer sized x-ray point source by two- dimensionally defined waveguide structures
- …
