135 research outputs found

    A Large-scale Analysis of the Marketplace Characteristics in Fiverr

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    Crowdsourcing platforms have become quite popular due to the increasing demand of human computation-based tasks. Though the crowdsourcing systems are primarily demand-driven like MTurk, supply-driven marketplaces are becoming increasingly popular. Fiverr is a fast growing supply-driven marketplace where the sellers post micro-tasks (gigs) and users purchase them for prices as low as $5. In this paper, we study the Fiverr platform as a unique marketplace and characterize the sellers, buyers and the interactions among them. We find that sellers are more appeasing in their interactions and try to woo their buyers into buying their gigs. There are many small tightly-knit communities existing in the seller-seller network who support each other. We also study Fiverr as a seller-driven marketplace in terms of sales, churn rates, competitiveness among various subcategories etc. and observe that while there are certain similarities with common marketplaces there are also many differences

    Discovery of Magnetospheric Interactions in the Doubly-Magnetic Hot Binary ϵ\epsilon Lupi

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    Magnetic fields are extremely rare in close, hot binaries, with only 1.5\% of such systems known to contain a magnetic star. The eccentric ϵ\epsilon Lupi system stands out in this population as the only close binary in which both stars are known to be magnetic. We report the discovery of strong, variable radio emission from ϵ\epsilon Lupi using the upgraded Giant Metrewave Radio Telescope (uGMRT) and the MeerKAT radio telescope.The light curve exhibits striking, unique characteristics including sharp, high-amplitude pulses that repeat with the orbital period, with the brightest enhancement occurring near periastron. The characteristics of the light curve point to variable levels of magnetic reconnection throughout the orbital cycle, making ϵ\epsilon Lupi the first known high-mass, main sequence binary embedded in an interacting magnetosphere. We also present a previously unreported enhancement in the X-ray light curve obtained from archival XMM-Newton data. The stability of the components' fossil magnetic fields, the firm characterization of their relatively simple configurations, and the short orbital period of the system make ϵ\epsilon Lupi an ideal target to study the physics of magnetospheric interactions. This system may thus help us to illuminate the exotic plasma physics of other magnetically interacting systems such as moon-planet, planet-star, and star-star systems including T Tauri binaries, RS CVn systems, and neutron star binaries.Comment: Accepted for publication in MNRAS, 16 pages, 12 figure

    COEXISTENCE OF POLYMORPHISM IN FECUNDITY GENES BMPR 1B AND GDF 9 OF INDIAN KENDRAPADA SHEEP

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    Present study was carried out to find out the status of mutations in three fecundity genes i.e. growth differentiation factor 9 (GDF9/FecG), bone morphogenetic protein 15 (BMP15/FecX) and bone morphogenetic protein receptor (BMPR1B/FecB) in Kendrapada sheep, the second most prolific sheep breed of India after Garole. Kendrapada ewes (n=85) were genotyped by Tetra-primer amplification refractory mutation system-PCR and a total of eleven SNP points over these three candidate fecundity genes (one point on FecB and five points each on BMP15 and GDF9) were assessed. Out of eleven, two SNP points, viz. FecB and G4 of GDF9 were found to be polymorphic in this breed. In this sheep breed average litter size of the ewes with non-carriers, heterozygous carrier and homozygous carrier of FecB locus mutation were 1.61, 1.80 and 2.06 respectively. G4 point of the GDF9 gene was also polymorphic with average litter size of noncarriers, heterozygous carrier and homozygous carrier ewes were 1.63, 2.00 and 1.91 respectively. This study establishes Kendrapada sheep as the sixth sheep breed after Belclare/Cambridge, Lacaune, Small-tailed Han, Garole and Bayanbulak sheep, where coexisting polymorphism has been found in two different fecundity genes (BMPRIB and GDF9 genes)

    Performance of the CMS Cathode Strip Chambers with Cosmic Rays

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    The Cathode Strip Chambers (CSCs) constitute the primary muon tracking device in the CMS endcaps. Their performance has been evaluated using data taken during a cosmic ray run in fall 2008. Measured noise levels are low, with the number of noisy channels well below 1%. Coordinate resolution was measured for all types of chambers, and fall in the range 47 microns to 243 microns. The efficiencies for local charged track triggers, for hit and for segments reconstruction were measured, and are above 99%. The timing resolution per layer is approximately 5 ns

    Performance and Operation of the CMS Electromagnetic Calorimeter

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    The operation and general performance of the CMS electromagnetic calorimeter using cosmic-ray muons are described. These muons were recorded after the closure of the CMS detector in late 2008. The calorimeter is made of lead tungstate crystals and the overall status of the 75848 channels corresponding to the barrel and endcap detectors is reported. The stability of crucial operational parameters, such as high voltage, temperature and electronic noise, is summarised and the performance of the light monitoring system is presented

    Calibration of the CMS Drift Tube Chambers and Measurement of the Drift Velocity with Cosmic Rays

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    CMS Data Processing Workflows during an Extended Cosmic Ray Run

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    Aligning the CMS Muon Chambers with the Muon Alignment System during an Extended Cosmic Ray Run

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    Alignment of the CMS muon system with cosmic-ray and beam-halo muons

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    This is the Pre-print version of the Article. The official published version of the Paper can be accessed from the link below - Copyright @ 2010 IOPThe CMS muon system has been aligned using cosmic-ray muons collected in 2008 and beam-halo muons from the 2008 LHC circulating beam tests. After alignment, the resolution of the most sensitive coordinate is 80 microns for the relative positions of superlayers in the same barrel chamber and 270 microns for the relative positions of endcap chambers in the same ring structure. The resolution on the position of the central barrel chambers relative to the tracker is comprised between two extreme estimates, 200 and 700 microns, provided by two complementary studies. With minor modifications, the alignment procedures can be applied using muons from LHC collisions, leading to additional significant improvements.This work is supported by FMSR (Austria); FNRS and FWO (Belgium); CNPq, CAPES, FAPERJ, and FAPESP (Brazil); MES (Bulgaria); CERN; CAS, MoST, and NSFC (China); COLCIENCIAS (Colombia); MSES (Croatia); RPF (Cyprus); Academy of Sciences and NICPB (Estonia); Academy of Finland, ME, and HIP (Finland); CEA and CNRS/IN2P3 (France); BMBF, DFG, and HGF (Germany); GSRT (Greece); OTKA and NKTH (Hungary); DAE and DST (India); IPM (Iran); SFI (Ireland); INFN (Italy); NRF (Korea); LAS (Lithuania); CINVESTAV, CONACYT, SEP, and UASLP-FAI (Mexico); PAEC (Pakistan); SCSR (Poland); FCT (Portugal); JINR(Armenia, Belarus, Georgia, Ukraine, Uzbekistan); MST and MAE (Russia); MSTDS (Serbia); MICINN and CPAN (Spain); Swiss Funding Agencies (Switzerland); NSC (Taipei); TUBITAK and TAEK (Turkey); STFC (United Kingdom); DOE and NSF (USA)
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