29,156 research outputs found

    Adenoid Cystic Carcinoma of External Auditory Canal

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    Adenoid cystic carcinoma is extremely rare tumour that accounts for approximately 5% of primary malignancy of external auditory canal. These tumours are related with a high risk of recurrences and significant morbidities from surgical management and adjuvant radiotherapy. Despite the aggressive management for these tumours, many patients succumb to distant metastasis, making overall prognosis of these tumours poor. Although ACC of EAC has been reported in 5th decade, but its occurrence in young patient is very rare. We report a rare case of ACC in a young 22 years old female, who presented with ear canal mass and ear pain. Biopsy suggested mass to be ACC. Patient underwent wide local excision followed by adjuvant radiotherapy

    Carbon Trading with Blockchain

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    Blockchain has the potential to accelerate the deployment of emissions trading systems (ETS) worldwide and improve upon the efficiency of existing systems. In this paper, we present a model for a permissioned blockchain implementation based on the successful European Union (EU) ETS and discuss its potential advantages over existing technology. We propose an ETS model that is both backwards compatible and future-proof, characterised by interconnectedness, transparency, tamper-resistance and high liquidity. Further, we identify key challenges to implementation of a blockchain ETS, as well as areas of future work required to enable a fully-decentralised blockchain ETS

    High pT pi0 Production and Angular Correlations in 158 AGeV p+A and Pb+Pb Collisions

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    Recent results of the WA98 experiment with p and Pb induced reactions at 158 AGeV are presented. Azimuthal gamma-gamma correlations at high pT were studied in search for a signal of jet-like structures. A clear indication for back-to-back correlations can be seen in p+A with a strong dependence on the pT of the photons and the size of the system. In Pb+Pb collisions in plane elliptic flow has been observed. Results on transverse mass spectra of neutral pions measured at central rapidity are presented for impact parameter selected Pb+Pb collisions. In going from peripheral to medium central collisions there is a nuclear enhancement increasing with transverse mass similar to the Cronin effect, while for very central collisions this enhancement appears to be weaker than expected.Comment: 4 pages, 2 figures, Talk presented at Quark Matter 2002, Nantes, France, July 18-24, 2002. To appear in the proceedings (Nucl. Phys. A

    Sponsored Search Auctions with Markovian Users

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    Sponsored search involves running an auction among advertisers who bid in order to have their ad shown next to search results for specific keywords. Currently, the most popular auction for sponsored search is the "Generalized Second Price" (GSP) auction in which advertisers are assigned to slots in the decreasing order of their "score," which is defined as the product of their bid and click-through rate. In the past few years, there has been significant research on the game-theoretic issues that arise in an advertiser's interaction with the mechanism as well as possible redesigns of the mechanism, but this ranking order has remained standard. From a search engine's perspective, the fundamental question is: what is the best assignment of advertisers to slots? Here "best" could mean "maximizing user satisfaction," "most efficient," "revenue-maximizing," "simplest to interact with," or a combination of these. To answer this question we need to understand the behavior of a search engine user when she sees the displayed ads, since that defines the commodity the advertisers are bidding on, and its value. Most prior work has assumed that the probability of a user clicking on an ad is independent of the other ads shown on the page. We propose a simple Markovian user model that does not make this assumption. We then present an algorithm to determine the most efficient assignment under this model, which turns out to be different than that of GSP. A truthful auction then follows from an application of the Vickrey-Clarke-Groves (VCG) mechanism. Further, we show that our assignment has many of the desirable properties of GSP that makes bidding intuitive. At the technical core of our result are a number of insights about the structure of the optimal assignment

    Photon Multiplicity Measurements : From SPS to RHIC and LHC

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    Results from the photon multiplicity measurements using a fine granularity preshower photon multiplicity detector (PMD) at CERN SPS are discussed. These include study of pseudo-rapidity distributions of photons, scaling of photon multiplicity with number of participating nucleons, centrality dependence of mean transverse momentum of photons, event-by-event fluctuations in photon multiplicity and localised charged-neutral fluctuations. Basic features of the PMD to be used in STAR experiment at RHIC and in ALICE experiment at LHC are also discussed.Comment: 12 pages, Invited talk at the 4th International Conference on the Physcis and Astrophysics of the Quark-Gluon-Plasma, November 2001, Jaipur, India, to appear in Praman

    Radiative rates and electron impact excitation rates for transitions in He II

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    We report calculations of energy levels, radiative rates, collision strengths, and effective collision strengths for transitions among the lowest 25 levels of the n <= 5 configurations of He~II. The general-purpose relativistic atomic structure package (GRASP) and Dirac atomic R-matrix code (DARC) are adopted for the calculations. Radiative rates, oscillator strengths, and line strengths are reported for all electric dipole (E1), magnetic dipole (M1), electric quadrupole (E2), and magnetic quadrupole (M2) transitions among the 25 levels. Furthermore, collision strengths and effective collision strengths are listed for all 300 transitions among the above 25 levels over a wide energy (temperature) range up to 9 Ryd (10**5.4 K). Comparisons are made with earlier available results and the accuracy of the data is assessed.Comment: 30 pages of text including 12 figures and 5 Tables will appear in ATOMS 5 (2017
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