1,048 research outputs found

    New evidence on the Fed's productivity in providing payments services

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    As the dominant provider of payments services, the efficiency with which the Federal Reserve provides such services in an important public policy issue. This paper examines the productivity of Federal Reserve check-processing offices during 1980-1999 using non-parametric estimation methods and newly developed methods for non-parametric inference and hypothesis testing. The results support prior studies that found little initial improvement in the Fed's efficiency with the imposition of pricing for Federal Reserve services in 1982. However, we find that median productivity improved substantially during the 1990s, and the dispersion across Fed offices declined.>Productivity ; Payment systems ; Check collection systems

    METHODS OF ENHANCING DYEABILITY OF POLYMERS

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    The invention relates to new methods of dyeing polymers. The methods include dispersing nanomaterials into the polymers to form polymer nanocompositres, and dyeing the polymer nanocomposites with a dye. The invention also relates to dyed polymers thus obtained and articles made from these dyed polymers

    Media and information literate citizens: think critically, click wisely!

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    Can we improve our societies by clicking wisely? Content providers such as libraries, archives, museums, media and digital communications companies can enable inclusive and sustainable development. However, they do not always live up to these ideals, which creates challenges for the users of these services. Content providers of all types open up new opportunities for lifelong learning. But at the same time, they open up challenges such as misinformation and disinformation, hate speech, and infringement of online privacy, among others. Media and information literacy is a set of competencies that help people to maximize advantages and minimize harms. Media and information literacy covers competencies that enable people to critically and effectively engage with: communications content; the institutions that facilitate this content; and the use of digital technologies. Capacities in these areas are indispensable for all citizens regardless of their ages or backgrounds. This pioneering curriculum presents a comprehensive competency framework of media and information literacy and offers educators and learners structured pedagogical suggestions. It features various detailed modules covering the range of competencies needed to navigate today’s communications ecosystem. This resource links media and information literacy to emerging issues, such as artificial intelligence, digital citizenship education, education for sustainable development, cultural literacy and the exponential rise in misinformation and disinformation. With effective use of this media and information literacy curriculum, everyone can become media and information literate as well as peer-educators of media and information literacy

    Enhanced dust heating in the bulges of early-type spiral galaxies

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    Stellar density and bar strength should affect the temperatures of the cool (T ~ 20-30 K) dust component in the inner regions of galaxies, which implies that the ratio of temperatures in the circumnuclear regions to the disk should depend on Hubble type. We investigate the differences between cool dust temperatures in the central 3 kpc and disk of 13 nearby galaxies by fitting models to measurements between 70 and 500 microns. We attempt to quantify temperature trends in nearby disk galaxies, with archival data from Spitzer/MIPS and new observations with Herschel/SPIRE, which were acquired during the first phases of the Herschel observations for the KINGFISH (key insights in nearby galaxies: a far-infrared survey with Herschel) sample. We fit single-temperature modified blackbodies to far-infrared and submillimeter measurements of the central and disk regions of galaxies to determine the temperature of the component(s) emitting at those wavelengths. We present the ratio of central-region-to-disk-temperatures of the cool dust component of 13 nearby galaxies as a function of morphological type. We find a significant temperature gradient in the cool dust component in all galaxies, with a mean center-to-disk temperature ratio of 1.15 +/- 0.03. The cool dust temperatures in the central ~3 kpc of nearby galaxies are 23(+/-3)% hotter for morphological types earlier than Sc, and only 9(+/-3)% hotter for later types. The temperature ratio is also correlated with bar strength, with only strongly barred galaxies having a ratio over 1.2. The strong radiation field in the high stellar density of a galactic bulge tends to heat the cool dust component to higher temperatures, at least in early-type spirals with relatively large bulges, especially when paired with a strong bar.Comment: Accepted for publication on the A&A Herschel Special Issu

    SPIRE imaging of M82: cool dust in the wind and tidal streams

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    M82 is a unique representative of a whole class of galaxies, starbursts with superwinds, in the Very Nearby Galaxy Survey with Herschel. In addition, its interaction with the M81 group has stripped a significant portion of its interstellar medium from its disk. SPIRE maps now afford better characterization of the far-infrared emission from cool dust outside the disk, and sketch a far more complete picture of its mass distribution and energetics than previously possible. They show emission coincident in projection with the starburst wind and in a large halo, much more extended than the PAH band emission seen with Spitzer. Some complex substructures coincide with the brightest PAH filaments, and others with tidal streams seen in atomic hydrogen. We subtract the far-infrared emission of the starburst and underlying disk from the maps, and derive spatially-resolved far-infrared colors for the wind and halo. We interpret the results in terms of dust mass, dust temperature, and global physical conditions. In particular, we examine variations in the dust physical properties as a function of distance from the center and the wind polar axis, and conclude that more than two thirds of the extraplanar dust has been removed by tidal interaction, and not entrained by the starburst wind.Comment: accepted in A&A Herschel special issu

    Search for Zgamma events with large missing transverse energy in ppbar collisions at sqrt(s)=1.96 TeV

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    We present the first search for supersymmetry (SUSY) in Zgamma final states with large missing transverse energy using data corresponding to an integrated luminosity of 6.2 fb-1 collected with the D0 experiment in ppbar collisions at sqrt(s)=1.96 TeV. This signature is predicted in gauge-mediated SUSY-breaking models, where the lightest neutralino is the next-to-lightest supersymmetric particle (NLSP) and is produced in pairs, possibly through decay from heavier supersymmetric particles. The NLSP can decay either to a Z boson or a photon and an associated gravitino that escapes detection. We exclude this model at the 95% C.L. for SUSY breaking scales of Lambda < 87 TeV, corresponding to neutralino masses of < 151 GeV.Comment: submitted to Phys. Rev. Let

    Journal Staff

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    We present the first measurements of the differential cross section d sigma/dp(T)(gamma) for the production of an isolated photon in association with at least two b-quark jets. The measurements consider photons with rapidities vertical bar y(gamma)vertical bar &lt; 1.0 and transverse momenta 30 &lt; p(T)(gamma) &lt; 200 GeV. The b-quark jets are required to have p(T)(jet) &gt; 15 GeVand vertical bar y(jet)vertical bar &lt; 1.5. The ratio of differential production cross sections for gamma + 2 b-jets to gamma + b-jet as a function of p(T)(gamma) is also presented. The results are based on the proton-antiproton collision data at root s = 1.96 TeV collected with the D0 detector at the Fermilab Tevatron Collider. The measured cross sections and their ratios are compared to the next- to- leading order perturbative QCD calculations as well as predictions based on the k(T)- factorization approach and those from the sherpa and pythia Monte Carlo event generators

    Search for right-handed W bosons in top quark decay

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    We present a measurement of the fraction f+ of right-handed W bosons produced in top quark decays, based on a candidate sample of ttˉt\bar{t} events in the lepton+jets decay mode. These data correspond to an integrated luminosity of 230pb^-1, collected by the DO detector at the Fermilab Tevatron ppˉp\bar{p} Collider at sqrt(s)=1.96 TeV. We use a constrained fit to reconstruct the kinematics of the ttˉt\bar{t} and decay products, which allows for the measurement of the leptonic decay angle θ\theta^* for each event. By comparing the cosθ\cos\theta^* distribution from the data with those for the expected background and signal for various values of f+, we find f+=0.00+-0.13(stat)+-0.07(syst). This measurement is consistent with the standard model prediction of f+=3.6x10^-4.Comment: Submitted to Physical Review D Rapid Communications 7 pages, 3 figure

    Measurement of Leptonic Asymmetries and Top Quark Polarization in ttbar Production

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    We present measurements of lepton (l) angular distributions in ttbar -> W+ b W- b -> l+ nu b l- nubar bbar decays produced in ppbar collisions at a center-of-mass energy of sqrt(s)=1.96TeV, where l is an electron or muon. Using data corresponding to an integrated luminosity of 5.4fb^-1, collected with the D0 detector at the Fermilab Collider, we find that the angular distributions of l- relative to anti-protons and l+ relative to protons are in agreement with each other. Combining the two distributions and correcting for detector acceptance we obtain the forward-backward asymmetry A^l_FB = (5.8 +- 5.1(stat) +- 1.3(syst))%, compared to the standard model prediction of A^l_FB (predicted) = (4.7 +- 0.1)%. This result is further combined with the measurement based on the analysis of the l+jets final state to obtain A^l_FB = (11.8 +- 3.2)%. Furthermore, we present a first study of the top-quark polarization.Comment: submitted versio
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