16,339 research outputs found

    New Limits on the Polarized Anisotropy of the Cosmic Microwave Background at Subdegree Angular Scales

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    We update the limit from the 90 GHz PIQUE ground-based polarimeter on the magnitude of any polarized anisotropy of the cosmic microwave radiation. With a second year of data, we have now limited both Q and U on a ring of 1 degree radius. The window functions are broad: for E-mode polarization, the effective l is = 191 +143 -132. We find that the E-mode signal can be no greater than 8.4 microK (95% CL), assuming no B-mode polarization. Limits on a possible B-mode signal are also presented.Comment: 4 pages, 3 figures, submitted to Astrophysical Journal Letter

    Evaluation of dental therapists undertaking dental examinations in a school setting in Scotland

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    Objective: To measure agreement between dental therapists and the Scottish gold-standard dentist undertaking National Dental Inspection Programme (NDIP) examinations. Methods: A study of interexaminer agreement between 19 dental therapists and the national gold-standard dentist was carried out. Pre-calibration training used the caries diagnostic criteria and examination techniques agreed by the British Association for the Study of Community Dentistry (BASCD). Twenty-three 5-year-old children (Primary 1) and 17 11-year-old children (Primary 7) children were examined. Agreement was assessed using kappa statistics on d 3 mft and D 3 MFT for P1 and P7 children, sensitivity and specificity values, and kappa statistics on d 3 t/D 3 T and ft/FT. Calibration data on P1 and P7 children from 2009–2012 involving dentists as examiners were used for comparison. Economic evaluation was undertaken using a cost minimization analysis approach. Results: The mean kappa score was 0.84 (SD 0.07) ranging from 0.69 to 0.94. All dental therapists scored good or very good agreement with the gold-standard dentist. This compares with historic NDIP calibration data with dentists, against the same gold-standard dentist, where the mean kappa value was 0.68 (SD 0.22) with a range of 0.35-1.00. The mean sensitivity score was 0.98 (SD 0.04) (range 0.88-1.0) and mean specificity score was 0.90 (SD 0.06) (range 0.78-0.96). Health economic analysis estimated that salary costs would be 33.6% lower if dental therapists were substituted for dentists in the year 2013, with an estimated saving of approximately £103 646 per annum on the national budget. Conclusion: We conclude that dental therapists show a high level of interexaminer agreement, and with the appropriate annual training and calibration, they could undertake dental examinations as part of the NDIP programme

    Near-infrared colors of minor planets recovered from VISTA - VHS survey (MOVIS)

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    The Sloan Digital Sky Survey (SDSS) and Wide-field Infrared Survey Explorer (WISE) provide information about the surface composition of about 100,000 minor planets. The resulting visible colors and albedos enabled us to group them in several major classes, which are a simplified view of the diversity shown by the few existing spectra. We performed a serendipitous search in VISTA-VHS observations using a pipeline developed to retrieve and process the data that corresponds to solar system objects (SSo). The colors and the magnitudes of the minor planets observed by the VISTA survey are compiled into three catalogs that are available online: the detections catalog (MOVIS-D), the magnitudes catalog (MOVIS-M), and the colors catalog (MOVIS-C). They were built using the third data release of the survey (VISTA VHS-DR3). A total of 39,947 objects were detected, including 52 NEAs, 325 Mars Crossers, 515 Hungaria asteroids, 38,428 main-belt asteroids, 146 Cybele asteroids, 147 Hilda asteroids, 270 Trojans, 13 comets, 12 Kuiper Belt objects and Neptune with its four satellites. The colors found for asteroids with known spectral properties reveal well-defined patterns corresponding to different mineralogies. The distributions of MOVIS-C data in color-color plots shows clusters identified with different taxonomic types. All the diagrams that use (Y-J) color separate the spectral classes more effectively than the (J-H) and (H-Ks) plots used until now: even for large color errors (<0.1), the plots (Y-J) vs (Y-Ks) and (Y-J) vs (J-Ks) provide the separation between S-complex and C-complex. The end members A, D, R, and V-types occupy well-defined regions.Comment: 19 pages, 16 figure

    A national power infrastructure for charge-on-the-move: An appraisal for Great Britain

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    The electrification of road transportation is a necessary step for coping with climate change. Charge-on-the-move is considered to be a key enabling factor in moving towards electric vehicles. The development of individual charging devices for implementing in-motion charging has been rapid but their integration with the road infrastructure at national scale is still in need of more comprehensive consideration. This work aims to outline the performance requirements of a national power infrastructure suitable for implementing charge-on-the-move. From an estimation of electric vehicles’ power requirements in conjunction with Great Britain’s road traffic data the anticipated power demand is expected to be augmented by 16 GW. Furthermore, a simulation tool is proposed to investigate the application of dynamic charging and the effects of system design variables. Based on that, a possible charging layout is suggested. Such infrastructure involves 30 kW chargers, 1.5 m length apiece, installed every 2.1 m and 4.3 m on motorways and rural sections of road respectively. Finally, a strategic overview for Great Britain suggests that the installation of a nationwide charging infrastructure of this type could be economically viable. Indeed, the cost to develop the infrastructure to enable the electrification of 86% of car-miles in Great Britain is around £76 billion at present prices

    Fundamental Behavior of Electric Field Enhancements in the Gaps Between Closely Spaced Nanostructures

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    We demonstrate that the electric field enhancement that occurs in a gap between two closely spaced nanostructures, such as metallic nanoparticles, is the result of a transverse electromagnetic waveguide mode. We derive an explicit semianalytic equation for the enhancement as a function of gap size, which we show has a universal qualitative behavior in that it applies irrespective of the material or geometry of the nanostructures and even in the presence of surface plasmons. Examples of perfect electrically conducting and Ag thin-wire antennas and a dimer of Ag spheres are presented and discussed.Comment: 9 pages and 4 figure

    Composite Reflective/Absorptive IR-Blocking Filters Embedded in Metamaterial Antireflection Coated Silicon

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    Infrared (IR) blocking filters are crucial for controlling the radiative loading on cryogenic systems and for optimizing the sensitivity of bolometric detectors in the far-IR. We present a new IR filter approach based on a combination of patterned frequency selective structures on silicon and a thin (50 μm\mu \textrm{m} thick) absorptive composite based on powdered reststrahlen absorbing materials. For a 300 K blackbody, this combination reflects \sim50\% of the incoming light and blocks \textgreater 99.8\% of the total power with negligible thermal gradients and excellent low frequency transmission. This allows for a reduction in the IR thermal loading to negligible levels in a single cold filter. These composite filters are fabricated on silicon substrates which provide excellent thermal transport laterally through the filter and ensure that the entire area of the absorptive filter stays near the bath temperature. A metamaterial antireflection coating cut into these substrates reduces in-band reflections to below 1\%, and the in-band absorption of the powder mix is below 1\% for signal bands below 750 GHz. This type of filter can be directly incorporated into silicon refractive optical elements
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