1,048 research outputs found
New evidence on the Fed's productivity in providing payments services
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
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!
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
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
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
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
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 < 1.0 and transverse momenta 30 < p(T)(gamma) < 200 GeV. The b-quark jets are required to have p(T)(jet) > 15 GeVand vertical bar y(jet)vertical bar < 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
We present a measurement of the fraction f+ of right-handed W bosons produced
in top quark decays, based on a candidate sample of 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
Collider at sqrt(s)=1.96 TeV. We use a constrained fit to reconstruct the
kinematics of the and decay products, which allows for the
measurement of the leptonic decay angle for each event. By comparing
the 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
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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