18,336 research outputs found
On the "Causality Paradox" of Time-Dependent Density Functional Theory
I show that the so-called causality paradox of time-dependent density
functional theory arises from an incorrect formulation of the variational
principle for the time evolution of the density. The correct formulation not
only resolves the paradox in real time, but also leads to a new expression for
the causal exchange-correlation kernel in terms of Berry curvature.
Furthermore, I show that all the results that were previously derived from
symmetries of the action functional remain valid in the present formulation.
Finally, I develop a model functional theory which explicitly demonstrates the
workings of the new formulation.Comment: 21 page
Apollo-11 lunar sample information catalogue
The Apollo 11 mission is reviewed with emphasis on the collection of lunar samples, their geologic setting, early processing, and preliminary examination. The experience gained during five subsequent missions was applied to obtain physical-chemical data for each sample using photographic and binocular microscope techniques. Topics discussed include: binocular examination procedure; breccia clast dexrriptuons, thin section examinations procedure typical breccia in thin section, typical basalt in thin section, sample histories, and chemical and age data. An index to photographs is included
1966 Beef Cattle Progress Report of Research Activities
Many beef cattle breeders in the United States and other countries are following the progress of the selection experiment at the Fort Robinson Beef Cattle Research Station, Crawford, Nebraska. Three lines of Hereford cattle from the same genetic foundation are under selection. Line 21 is selected for 200-day weight. Line 22 is selected for yearling weight. Line 23 is selected for an index combining yearling weight and a score for muscling and fat thickness.
Each line is operated as a closed herd so it will be possible to determine how much improvement in economic traits can be made by selecting all replacement stock from within the same herd. Starting in 1966 there will be 150 calving cows in each line. Six herd sires are used each year. Two bulls and 25 heifers are selected to add to each line each year. Heifers are bred to calve first as two year olds. Cow numbers will be maintained at 150 by culling the oldest cows and those that fail to conceive or have a major physical unsoundness. Bulls are replaced after their third breeding season
Beef Cattle Progress Report
Efficiency of sugar beet farming can be improved by feeding beet top silage to livestock.
In two recent trials at the Scotts Bluff Experiment Station lambs fed unwilted beet top silage as the only roughage gained significantly faster than lambs fed corn silage.
Amounts of concentrates were comparable (Nebraska Experiment Station Quarterly, Fall, 1962).
This experiment compared the feeding value of a complete mixture of unwilted beet tops and concentrate added at the time of ensiling, with beet top silage and concentrate handled separately. A conventional corn silage and concentrate ration was used as a control.
Results showed that a complete ration prepared by mixing unwilted beet tops and concentrates at the time of ensiling did not produce greater gains than a ration of unwilted beet top silage and concentrates fed separately
Temperatures of dust and gas in S~140
In dense parts of interstellar clouds (> 10^5 cm^-3), dust & gas are expected
to be in thermal equilibrium, being coupled via collisions. However, previous
studies have shown that the temperatures of the dust & gas may remain decoupled
even at higher densities. We study in detail the temperatures of dust & gas in
the photon-dominated region S 140, especially around the deeply embedded
infrared sources IRS 1-3 and at the ionization front. We derive the dust
temperature and column density by combining Herschel PACS continuum
observations with SOFIA observations at 37 m and SCUBA at 450 m. We
model these observations using greybody fits and the DUSTY radiative transfer
code. For the gas part we use RADEX to model the CO 1-0, CO 2-1, 13CO 1-0 and
C18O 1-0 emission lines mapped with the IRAM-30m over a 4' field. Around IRS
1-3, we use HIFI observations of single-points and cuts in CO 9-8, 13CO 10-9
and C18O 9-8 to constrain the amount of warm gas, using the best fitting dust
model derived with DUSTY as input to the non-local radiative transfer model
RATRAN. We find that the gas temperature around the infrared sources varies
between 35 and 55K and that the gas is systematically warmer than the dust by
~5-15K despite the high gas density. In addition we observe an increase of the
gas temperature from 30-35K in the surrounding up to 40-45K towards the
ionization front, most likely due to the UV radiation from the external star.
Furthermore, detailed models of the temperature structure close to IRS 1 show
that the gas is warmer and/or denser than what we model. Finally, modelling of
the dust emission from the sub-mm peak SMM 1 constrains its luminosity to a few
~10^2 Lo. We conclude that the gas heating in the S 140 region is very
efficient even at high densities, most likely due to the deep UV penetration
from the embedded sources in a clumpy medium and/or oblique shocks.Comment: 15 pages, 23 figures, 4 tables, accepted for publication in A&
Stress condensation in crushed elastic manifolds
We discuss an M-dimensional phantom elastic manifold of linear size L crushed
into a small sphere of radius R << L in N-dimensional space. We investigate the
low elastic energy states of 2-sheets (M=2) and 3-sheets (M=3) using analytic
methods and lattice simulations. When N \geq 2M the curvature energy is
uniformly distributed in the sheet and the strain energy is negligible. But
when N=M+1 and M>1, both energies appear to be condensed into a network of
narrow M-1 dimensional ridges. The ridges appear straight over distances
comparable to the confining radius R.Comment: 4 pages, RevTeX + epsf, 4 figures, Submitted to Phys. Rev. Let
Apollo 14 coarse fines (4-10 mm) sample location and classification
The 4 to 10 mm sieve fraction from the soil samples collected during the Apollo 14 Mission was identified and described. Examination and description of the fines were carried out in nitrogen-filled, stainless steel cabinets during a general examination of the Apollo 14 sample collection. Each particle was held between forceps, dusted in a jet of N2, and placed on a teflon-covered stage. They were examined with a binocular microscope, separated by lithology, and the lithologic types described. Weights of individual particles in the fraction ranged from about 0.10 to 0.50 gm, large enough in size for studies of age, chemistry, and petrology to be accomplished
Limits on the Mass, Velocity and Orbit of PSR J19336211
We present a high-precision timing analysis of PSR J19336211, a
millisecond pulsar (MSP) with a 3.5-ms spin period and a white dwarf (WD)
companion, using data from the Parkes radio telescope. Since we have accurately
measured the polarization properties of this pulsar we have applied the matrix
template matching approach in which the times of arrival are measured using
full polarimetric information. We achieved a weighted root-mean-square timing
residuals (rms) of the timing residuals of 1.23 , 15.5
improvement compared to the total intensity timing analysis. After studying the
scintillation properties of this pulsar we put constraints on the inclination
angle of the system. Based on these measurements and on mapping we put
a 2- upper limit on the companion mass (0.44 M). Since this
mass limit cannot reveal the nature of the companion we further investigate the
possibility of the companion to be a He WD. Applying the orbital period-mass
relation for such WDs, we conclude that the mass of a He WD companion would be
about 0.260.01 M which, combined with the measured mass function
and orbital inclination limits, would lead to a light pulsar mass
1.0 M. This result seems unlikely based on current neutron star
formation models and we therefore conclude that PSR J19336211 most likely
has a CO WD companion, which allows for a solution with a more massive pulsar
Rotating Boson Stars and Q-Balls
We consider axially symmetric, rotating boson stars. Their flat space limits
represent spinning Q-balls. We discuss their properties and determine their
domain of existence. Q-balls and boson stars are stationary solutions and exist
only in a limited frequency range. The coupling to gravity gives rise to a
spiral-like frequency dependence of the boson stars. We address the flat space
limit and the limit of strong gravitational coupling. For comparison we also
determine the properties of spherically symmetric Q-balls and boson stars.Comment: 22 pages, 18 figure
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