2,770 research outputs found

    Continuous monitoring of the lunar or Martian subsurface using on-board pattern recognition and neural processing of Rover geophysical data

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    The ultimate goal is to create an extraterrestrial unmanned system for subsurface mapping and exploration. Neural networks are to be used to recognize anomalies in the profiles that correspond to potentially exploitable subsurface features. The ground penetrating radar (GPR) techniques are likewise identical. Hence, the preliminary research focus on GPR systems will be directly applicable to seismic systems once such systems can be designed for continuous operation. The original GPR profile may be very complex due to electrical behavior of the background, targets, and antennas, much as the seismic record is made complex by multiple reflections, ghosting, and ringing. Because the format of the GPR data is similar to the format of seismic data, seismic processing software may be applied to GPR data to help enhance the data. A neural network may then be trained to more accurately identify anomalies from the processed record than from the original record

    HgSe, a highly electronegative stable metallic contact for semiconductor devices

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    Schottky barriers formed by the highly electronegative substance HgSe on n-ZnS and on n-ZnSe have been characterized by capacitance-voltage and photoresponse measurements. The barriers are about 0.5 eV greater than Au barriers on these n-type substrates. HgSe contacts are stable under ambient conditions and are easily fabricated, making them attractive for device use

    Highly electronegative metallic contacts to semiconductors using polymeric sulfur nitride

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    The Schottky barriers formed on nā€ZnS and nā€ZnSe by polymeric sulfur nitride have been compared to barriers formed by Au. Barrier energies as determined by photoresponse, currentā€voltage, and capacitanceā€voltage methods show that (SN)_x is approximately 1.0 eV higher than Au on nā€ZnS and 0.3ā€“0.4 eV higher than Au on nā€ZnSe. We believe that this is the first report of any metallic contact more electronegative than Au

    A review of UK media coverage of physical activity associated with the publication of special issues in a high-impact medical journal

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    Objectives: The media is a substantial vehicle for conveying public health messages to the public. This study examined the extent to which the publication of special issues in a high-impact medical journal in 2012 and 2016 generated media interest in physical activity and health in the UK and explored the main issues that were reported. Study design: This is a systematic narrative review of print media. Methods: Relevant print news articles were identified by searching Factiva and Google News. The timeframe of each search was 2 weeks, using the publication date of each special issue as the anchor point. Overall, 20 articles were included in the analysis for 2012 and 37 articles for 2016. Results: The news media coverage was encouraging for the profile of physical activity and health. In 2012 and 2016, common themes included the benefits of physical activity and the risks of being inactive, comparisons between mortality rates from physical inactivity and smoking and the recommended volume of physical activity to benefit health. Conclusions: The profile given to an issue through prestigious scientific publication is one of the levers for community attention and policy change. Efforts are needed to further use the media for improving policy, practice and public awareness, which are antecedents to population health change

    Growth and characterization of ZnTe films grown on GaAs, InAs, GaSb, and ZnTe

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    We report the successful growth of ZnTe on nearly lattice-matched III-V buffer layers of InAs (0.75%), GaSb (0.15%), and on GaAs and ZnTe by molecular beam epitaxy. In situ reflection high-energy electron diffraction measurements showed the characteristic streak patterns indicative of two-dimensional growth. Photoluminescence measurements on these films show strong and sharp features near the band edge with no detectable luminescence at longer wavelengths. The integrated photoluminescence intensity from the ZnTe layers increased with better lattice match to the buffer layer. The ZnTe epilayers grown on high-purity ZnTe substrates exhibited stronger luminescence than the substrates. We observe narrow luminescence linewidths (full width at half maximum ~ 1ā€“2 ƅ) indicative of uniform high quality growth. Secondary-ion mass spectroscopy and electron microprobe measurements, however, reveal substantial outdiffusion of Ga and In for growths on the III-V buffer layers

    The size of MRK 231 at 10 Āµm

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    A technique is described for obtaining high-sensitivity measurements with high spatial resolution at 10 Āµm. An application of the method to Mrk 231 confirms the point like nature of the nucleus at 10 Āµm

    Lyman alpha absorption lines from mini pancakes

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    [Abridged abstract:] Recent numerical simulations show that many \lyal absorption lines of column densities \nha \la 10^{15} cmāˆ’2^{-2} are produced in transient, mini pancakes. Such pancakes are modeled here, approximating the initial perturbation leading to the formation of the pancake as a single sinusoidal wave. The density and temperature profiles of the gas in the pancake are determined for zcāˆ¼3z_c \sim 3, where zcz_c is the collapse redshift. The \lyal absorption line profiles for a line of sight through the pancake are then calculated. The absorption lines in general have wings signifying bulk motions in the gas. It is shown that the deviation from a single Voigt profile is large for small H I column density lines, in which the effect of bulk motions is large. For lines with \nha > 10^{13} cmāˆ’2^{-2}, high temperature tend to wash out the signatures of bulk motion. The analytical modeling of mini pancakes associated with \lyal forest lines --- with 10^{13} \la \nha \la 10^{15} cmāˆ’2^{-2}---gives the corresponding mass scales. It is shown here that, for typical values of cosmological parameters, absorption lines with \nha \sim 10^{14} cmāˆ’2^{-2} correspond to structures with baryonic mass of Mbāˆ¼1010M_b \sim 10^{10} MāŠ™_{\odot} with an overdensity of āˆ¼10\sim 10 at zāˆ¼3z \sim 3. The value of \nha can change by a factor āˆ¼3\sim 3 in the course of evolution of the pancake in time. It is also shown that there is an upper limit to \nha from a pancake due to the slow recombination rate and the importance of collisional ionization at high temperatures. Mini pancakes do not give rise to \lyal lines with \nha \ga 10^{14.5} cmāˆ’2^{-2}, for \j21=1 and Ī©IGMāˆ¼0.03\Omega_{IGM} \sim 0.03.Comment: Latex with aaspp4.sty (25 pages), 6 figures, Accepted for publication in The Astrophysical Journa

    Statistical Arbitrage Mining for Display Advertising

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    We study and formulate arbitrage in display advertising. Real-Time Bidding (RTB) mimics stock spot exchanges and utilises computers to algorithmically buy display ads per impression via a real-time auction. Despite the new automation, the ad markets are still informationally inefficient due to the heavily fragmented marketplaces. Two display impressions with similar or identical effectiveness (e.g., measured by conversion or click-through rates for a targeted audience) may sell for quite different prices at different market segments or pricing schemes. In this paper, we propose a novel data mining paradigm called Statistical Arbitrage Mining (SAM) focusing on mining and exploiting price discrepancies between two pricing schemes. In essence, our SAMer is a meta-bidder that hedges advertisers' risk between CPA (cost per action)-based campaigns and CPM (cost per mille impressions)-based ad inventories; it statistically assesses the potential profit and cost for an incoming CPM bid request against a portfolio of CPA campaigns based on the estimated conversion rate, bid landscape and other statistics learned from historical data. In SAM, (i) functional optimisation is utilised to seek for optimal bidding to maximise the expected arbitrage net profit, and (ii) a portfolio-based risk management solution is leveraged to reallocate bid volume and budget across the set of campaigns to make a risk and return trade-off. We propose to jointly optimise both components in an EM fashion with high efficiency to help the meta-bidder successfully catch the transient statistical arbitrage opportunities in RTB. Both the offline experiments on a real-world large-scale dataset and online A/B tests on a commercial platform demonstrate the effectiveness of our proposed solution in exploiting arbitrage in various model settings and market environments.Comment: In the proceedings of the 21st ACM SIGKDD international conference on Knowledge discovery and data mining (KDD 2015

    Rationale and design of a randomised phase III registration trial investigating finerenone in participants with type 1 diabetes and chronic kidney disease: The FINE-ONE trial

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    AIMS: Despite guideline-recommended treatments, including renin angiotensin system inhibition, up to 40 % of individuals with type 1 diabetes develop chronic kidney disease (CKD) putting them at risk of kidney failure. Finerenone is approved to reduce the risk of kidney failure in individuals with type 2 diabetes. We postulate that finerenone will demonstrate benefits on kidney outcomes in people with type 1 diabetes. METHODS: FINE-ONE (NCT05901831) is a randomised, placebo-controlled, double-blind phase III trial of 7.5 months\u27 duration in āˆ¼220 adults with type 1 diabetes, urine albumin/creatinine ratio (UACR) of ā‰„ 200-\u3c 5000 mg/g (ā‰„ 22.6-\u3c 565 mg/mmol) and eGFR of ā‰„ 25-\u3c 90 ml/min/1.73 m RESULTS: The primary endpoint is relative change in UACR from baseline over 6 months. UACR is used as a bridging biomarker (BB), since the treatment effect of finerenone on UACR was associated with its efficacy on kidney outcomes in the type 2 diabetes trials. Based on regulatory authority feedback, UACR can be used as a BB for kidney outcomes to support registration of finerenone in type 1 diabetes, provided necessary criteria are met. Secondary outcomes include incidences of treatment-emergent adverse events, treatment-emergent serious adverse events and hyperkalaemia. CONCLUSIONS: FINE-ONE will evaluate the efficacy and safety of finerenone in type 1 diabetes and CKD. Finerenone could become the first registered treatment for CKD associated with type 1 diabetes in almost 30 years. TRIAL REGISTRATION: ClinicalTrials.gov NCT05901831

    Radial Redshift Space Distortions

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    The radial component of the peculiar velocities of galaxies cause displacements in their positions in redshift space. We study the effect of the peculiar velocities on the linear redshift space two point correlation function. Our analysis takes into account the radial nature of the redshift space distortions and it highlights the limitations of the plane parallel approximation. We consider the problem of determining the value of \beta and the real space two point correlation function from the linear redshift space two point correlation function. The inversion method proposed here takes into account the radial nature of the redshift space distortions and can be applied to magnitude limited redshift surveys that have only partial sky coverage.Comment: 26 pages including 11 figures, to appear in Ap
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