5,656 research outputs found
Catalog of Lunar Craters I
This catalog gives the selenographic coordinates of all craters observable on a selected portion of the moon's surface. The diameter of the crater together with comments on shape are also given. Approximately 25 per cent of the craters have been measured previously by other observers. The catalog gives the position found in the present series of measurements and the name adopted by the International Astronomical Union
Precise Determination of Electroweak Parameters in Neutrino-Nucleon Scattering
A systematic error in the extraction of from nuclear deep
inelastic scattering of neutrinos and antineutrinos arises from higher-twist
effects arising from nuclear shadowing. We explain that these effects cause a
correction to the results of the recently reported significant deviation from
the Standard Model that is potentially as large as the deviation claimed, and
of a sign that cannot be determined without an extremely careful study of the
data set used to model the input parton distribution functions.Comment: 3pages, 0 figures, version to be published by IJMP
Nuclear Quasi-Elastic Electron Scattering Limits Nucleon Off-Mass Shell Properties
The use of quasi-elastic electron nucleus scattering is shown to provide
significant constraints on models of the proton electromagnetic form factor of
off-shell nucleons. Such models can be constructed to be consistent with
constraints from current conservation and low-energy theorems, while also
providing a contribution to the Lamb shift that might potentially resolve the
proton radius puzzle in muonic hydrogen. However, observations of quasi-elastic
scattering limit the overall strength of the off-shell form factors to values
that correspond to small contributions to the Lamb shift.Comment: 11 pages, 2 figures. Resubmission to improve the clarity, and correct
possible misconception
Electron-phonon coupling and electron self-energy in electron-doped graphene: calculation of angular resolved photoemission spectra
We obtain analytical expressions for the electron self-energy and the
electron-phonon coupling in electron-doped graphene using electron-phonon
matrix elements extracted from density functional theory simulations. From the
electron self-energies we calculate angle resolved photoemission spectra. We
demonstrate that the measured kink at eV from the Fermi level is
actually composed of two features, one at eV due to the
twofold degenerate E mode, and a second one at eV due to
the A mode. The electron-phonon coupling extracted from the kink
observed in ARPES experiments is roughly a factor of 5.5 larger than the
calculated one. This disagreement can only be partially reconciled by the
inclusion of resolution effects. Indeed we show that a finite resolution
increases the apparent electron-phonon coupling by underestimating the
renormalization of the electron velocity at energies larger than the kinks
positions. The discrepancy between theory and experiments is thus reduced to a
factor of 2.2. From the linewidth of the calculated ARPES spectra we
obtain the electron relaxation time. A comparison with available experimental
data in graphene shows that the electron relaxation time detected in ARPES is
almost two orders of magnitudes smaller than what measured by other
experimental techniques.Comment: 9 pages, 7 figures, see also Matteo Calandra and Francesco Mauri,
arXiv:0707.149
Photoproduction in semiconductors by onset of magnetic field
The energy bands of a semiconductor are lowered by an external magnetic
field. When a field is switched on, the straight-line trajectories near the top
of the occupied valence band are curved into Landau orbits and Bremsstrahlung
is emitted until the electrons have settled in their final Fermi distribution.
We calculate the radiated energy, which should be experimentally detectable,
and suggest that a semiconductor can be cooled by an oscillating magnetic
field
Comparison of Nucleon Form Factors from Lattice QCD Against the Light Front Cloudy Bag Model and Extrapolation to the Physical Mass Regime
We explore the possibility of extrapolating state of the art lattice QCD
calculations of nucleon form factors to the physical regime. We find that the
lattice results can be reproduced using the Light Front Cloudy Bag Model by
letting its parameters be analytic functions of the quark mass. We then use the
model to extend the lattice calculations to large values of Q^{2} of interest
to current and planned experiments. These functions are also used to define
extrapolations to the physical value of the pion mass, thereby allowing us to
study how the predicted zero in G_{E}(Q^{2})/G_{M}(Q^{2}) varies as a function
of quark mass.Comment: 31 pages, 22 figure
Simulation and Optimization Modeling for Drive-Through Mass Vaccination – A Generalized Approach
Proper planning and execution of mass vaccination at the onset of a pandemic outbreak is important for local health departments. Mass vaccination clinics are required to be setup and run for naturally occurring pandemic outbreaks or even in response to terrorist attacks, e.g., anthrax attack. Walk-in clinics have often been used to administer vaccines. When a large percentage of a population must be vaccinated to mitigate the ill-effects of an attack or pandemic, drive-through clinics appear to be more effective because a much higher throughput can be achieved when compared to walk-in clinics. There are other benefits as well. For example, the spread of the disease can be minimized because infected patients are not exposed to uninfected patients. This research extends the simulation modeling work that was done for a mass vaccination drive-through clinic in the city of Louisville in November 2009. This clinic is the largest clinic set up in Louisville with more than 19,000 patients served, over two-thirds via ten drive-through lanes. The intent of the model in this paper is to illustrate a general tool that can be customized for a community of any size. The simulation-optimization tool will allow decision makers to investigate several interacting control variables in a simultaneous fashion; any of several criterion models in which various performance measures are either optimized or constrained, can be investigated. The model helps the decision maker determine the required number of Points of Dispense (POD) lanes, number and length of the lanes for consent hand outs and fill in, staff needed at the consent handout stations and PODs, and average user waiting time in the system
W. S. Merwin: 02-29-1968
Merwin discusses his changing poetic style, saying that he never stays excited about any style for very long, and that he now wants to write about direct experiences. He talks about the gradual abandonment of punctuation in his poems and the reliance on the language of a poem that a lack of punctuation highlights. Merwin also talks about the inability to shut the politics of the day out of his poems, and the mutual revulsion between art and topicality.https://digitalcommons.brockport.edu/writers_videos/1031/thumbnail.jp
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