399,209 research outputs found
The effect of small inter-pulsar distance variations in stochastic gravitational wave background searches with Pulsar Timing Arrays
One of the primary objectives for Pulsar Timing Arrays (PTAs) is to detect a
stochastic background generated by the incoherent superposition of
gravitational waves (GWs), in particular from the cosmic population of
supermassive black hole binaries. Current stochastic background searches assume
that pulsars in a PTA are separated from each other and the Earth by many GW
wavelengths. As more millisecond pulsars are discovered and added to PTAs, some
may be separated by only a few radiation wavelengths or less, resulting in
correlated GW phase changes between close pulsars in the array. Here we
investigate how PTA overlap reduction functions (ORFs), up to quadrupole order,
are affected by these additional correlated phase changes, and how they are in
turn affected by relaxing the assumption that all pulsars are equidistant from
the solar system barycenter. We find that in the low frequency GW background
limit of ~Hz, and for pulsars at varying distances from the
Earth, that these additional correlations only affect the ORFs by a few percent
for pulsar pairs at large angular separations, as expected. However when nearby
(order 100 pc) pulsars are separated by less than a few degrees, the correlated
phase changes can introduce variations of a few tens of percent in the
magnitude of the isotropic ORF, and much larger fractional differences in the
anisotropic ORFs-- up to 188 in the , ORF for equidistant pulsars
separated by 3 degrees. In fact, the magnitude of most of the anisotropic ORFs
is largest at small, but non-zero, pulsar separations. Finally, we write down a
small angle approximation for the correlated phase changes which can easily be
implemented in search pipelines, and for completeness, examine the behavior of
the ORFs for pulsars which lie at a radiation wavelength from the Earth.Comment: 16 pages, 8 figures, submitted to PR
Quantifying Diachronic Variability: The 'Ain Difla rockshelter (Jordan) and the Evolution of Levantine Mousterian Technology
Condette Jean-François. RAYNAL Pierre, voir CHAUDRU de RAYNAL Pierre. In: , . Les recteurs d'académie en France de 1808 à 1940. Tome II, Dictionnaire biographique. Paris : Institut national de recherche pédagogique, 2006. p. 327. (Histoire biographique de l'enseignement, 12
2011 Annual Report - Fair Labor Association
This document is part of a digital collection provided by the Martin P. Catherwood Library, ILR School, Cornell University, pertaining to the effects of globalization on the workplace worldwide. Special emphasis is placed on labor rights, working conditions, labor market changes, and union organizing.FLA_2012_AR_2011.pdf: 421 downloads, before Oct. 1, 2020
Bandgap narrowing in Mn doped GaAs probed by room-temperature photoluminescence
The electronic band structure of the (Ga,Mn)As system has been one of the
most intriguing problems in solid state physics over the past two decades.
Determination of the band structure evolution with increasing Mn concentration
is a key issue to understand the origin of ferromagnetism. Here we present room
temperature photoluminescence and ellipsometry measurements of
Ga_{100%-x}Mn_{x}As alloy. The up-shift of the valence-band is proven by the
red shift of the room temperature near band gap emission from the
Ga_{100%-x}Mn_{x}As alloy with increasing Mn content. It is shown that even a
doping by 0.02 at.% of Mn affects the valence-band edge and it merges with the
impurity band for a Mn concentration as low as 0.6 at.%. Both X-ray diffraction
pattern and high resolution cross-sectional TEM images confirmed full
recrystallization of the implanted layer and GaMnAs alloy formation.Comment: 24 pages, 7 figures, accepted at Phys. Rev. B 201
Interim report on the progress of an inventory of artesian wells in Florida: leading to the enforcement of sections 370.051 - 370.54, Florida statues
One of the causes of lower artesian pressure, water
waste and aquifer contamination is the misuse and insufficient
care of artesian wells. In 1953, Senate Bill No. 57, entitled
"An Act to Protect and Control the Artesian Waters of the
State" (see Appendix) became a law. This law was passed
through the efforts exerted by leading members of the Senate
and the House of Representatives, who understood the need
for a wise and controlled expenditure of our most valuable
natural resource.
The State Geologist and his authorized representatives
were designated by this law to enforce this conservation
measure; however, no financial provision was included for
the 1953-55 biennium. The proposed program of the Florida
Geological Survey for this biennium did not include the funds
nor provide any full-time personnel for the enforcement of
this statute. As a result, little actual work was accomplished during these two years, although much time was given to
planning and discussion of the problem.
Realizing that this program could provide additional basic
data needed in the analysis of the water-supply problem, the
State Geologist sought and was granted by the 1955 Legislature
adequate funds with which to activate the first phase of the
enforcement of Florida Statute No. 370.051-054.
Enumerated below is a summary of the progress made
on this investigation as outlined previously:
1. Data have been collected on 967 wildly flowing wells
in 22 counties.
2. Chloride determinations have been run on 850 of the
967 wells.
3. Of the 967 wells, 554 have chlorides in excess of the
250 ppm, the upper limit assigned by the State Board
of Health for public consumption.
4. Water escapes at the rate of 37, 762 gallons per minute
from these 967 wells. This amounts to 54, 377, 280
gallons per day.
The investigation is incomplete at this time; therefore,
no final conclusions can be reached. However, from data
already collected, the following recommendations are proposed:
1. That the present inventory of wildly flowing wells be
completed for the entire State.
2. That the current inventory of wildly flowing wells be
expanded at the conclusion of the present inventory
to include all flowing wells.
3. That a complete statewide inventory program be
established and conducted in cooperation with the
Ground Water Branchof the U.S. Geological Survey.
4. That the enforcement functions as set down in Sections
370.051/.054, Florida Statutes, be separated from
the program to collect water-resource data and that
these functions be given to the Water Resources
Department, if such is created (to be recommended
by the Water Resources Study Commission in a water
policy law presented to the 1957 Legislature).
5. That the research phase (well inventory) of the program
remain under the direction of the Florida Geological
Survey. (PDF contains 204 pages.
Tracking Chart 2009 Hanesbrands, Taiwan
Outlines the specific problems that were found by monitors and the action taken by the HanesBrand Company in response to an FLA audit of a factory in Taiwan
Isolation of two Kocuria species capable of growing on various polycyclic aromatic hydrocarbons
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