173 research outputs found
Cold imprint of supervoids in the Cosmic Microwave Background re-considered with Planck and BOSS DR10
We analyze publicly available void catalogs of the Baryon Oscillation
Spectroscopic Survey Data Release 10 at redshifts . The first goal
of this paper is to extend the Cosmic Microwave Background stacking analysis of
previous spectroscopic void samples at . In addition, the DR10 void
catalog provides the first chance to spectroscopically probe the volume of the
Granett et al. (2008) supervoid catalog that constitutes the only set of voids
which has shown a significant detection of a cross-correlation signal between
void locations and average CMB chill. We found that the positions of voids
identified in the spectroscopic DR10 galaxy catalog typically do not coincide
with the locations of the Granett et al. supervoids in the overlapping volume,
in spite of the presence of large underdense regions of high void-density in
DR10. This failure to locate the same structures with spectroscopic redshifts
may arise due to systematic differences in the properties of voids detected in
photometric and spectroscopic samples. In the stacking measurement, we first
find a imprint for 35 of the 50 Granett et
al. supervoids available in the DR10 volume. For the DR10 void catalog, lacking
a prior on the number of voids to be considered in the stacking analysis, we
find that the correlation measurement is fully consistent with no correlation.
However, the measurement peaks with amplitude
for the a posteriori-selected 44 largest voids of size that does
match in terms of amplitude and number of structures the Granett et al.
observation, although at different void positions.Comment: 9 pages, 7 figures, accepted for publication in MNRA
The Integrated Sachs-Wolfe Signal from BOSS Super-Structures
Cosmic structures leave an imprint on the microwave background radiation
through the integrated Sachs-Wolfe effect. We construct a template map of the
linear signal using the SDSS-III Baryon Acoustic Oscillation Survey at redshift
0.43 < z < 0.65. We verify the imprint of this map on the Planck CMB
temperature map at the 97% confidence level and show consistency with the
density-temperature cross-correlation measurement. Using this ISW
reconstruction as a template we investigate the presence of ISW sources and
further examine the properties of the Granett-Neyrinck-Szapudi supervoid and
supercluster catalogue. We characterise the three-dimensional density profiles
of these structures for the first time and demonstrate that they are
significant structures. Model fits demonstrate that the supervoids are
elongated along the line-of-sight and we suggest that this special orientation
may be picked out by the void-finding algorithm in photometric redshift space.
We measure the mean temperature profiles in Planck maps from public void and
cluster catalogues. In an attempt to maximise the stacked ISW signal we
construct a new catalogue of super-structures based upon local peaks and
troughs of the gravitational potential. However, we do not find a significant
correlation between these structures and the CMB temperature.Comment: Updated to match journal articl
Cross-correlation of WMAP7 and the WISE Full Data Release
We measured the cross-correlation of the Wilkinson Microwave Anisotropy Probe
(WMAP) 7 year temperature map and the full sky data release of the Wide-field
Infrared Survey Explorer (WISE) galaxy map. Using careful mapmaking and masking
techniques we find a positive cross-correlation signal. The results are fully
consistent with a Lambda-CDM Universe, although not statistically significant.
Our findings are robust against changing the galactic latitude cut from |b|>10
to |b|>20 and no color dependence was detected when we used WMAP Q, V or W
maps. We confirm higher significance correlations found in the preliminary data
release. The change in significance is consistent with cosmic variance.Comment: 5 pages, 4 figures, Accepted for publication in MNRAS Letter
Semiconductor Fab Scheduling with Self-Supervised and Reinforcement Learning
Semiconductor manufacturing is a notoriously complex and costly multi-step
process involving a long sequence of operations on expensive and
quantity-limited equipment. Recent chip shortages and their impacts have
highlighted the importance of semiconductors in the global supply chains and
how reliant on those our daily lives are. Due to the investment cost,
environmental impact, and time scale needed to build new factories, it is
difficult to ramp up production when demand spikes.
This work introduces a method to successfully learn to schedule a
semiconductor manufacturing facility more efficiently using deep reinforcement
and self-supervised learning. We propose the first adaptive scheduling approach
to handle complex, continuous, stochastic, dynamic, modern semiconductor
manufacturing models. Our method outperforms the traditional hierarchical
dispatching strategies typically used in semiconductor manufacturing plants,
substantially reducing each order's tardiness and time until completion. As a
result, our method yields a better allocation of resources in the semiconductor
manufacturing process
ELECTROCHEMICAL BEHAVIOUR OF BENZIMIDAZOLES II. PREPARATION OF A BIOLOGICALLY ACTIVE COMPOUND BY ELECTROREDUCTIVE DECARBOXYMETHYLATION
Based on steady-state voltammetric experiments, preparative electrochemical reduction
of the 1 ,3,5-triazino-(1 ,2-a)-benzimidazole-1 (2H )-carboxylic acid-3-dodecyl-3,4-dihydro-,
methylester 1 was carried out on Hg. Pb and Pt cathodes, in DMF /TBAP and
MeCN /TBAP electrolytes. In all cases reduction resulted in the decarboxymethylated
derivative 2 by cleavage of the carbon-nitrogen bond. The best product and current yield
for 2 formation could be achieved when Pt was used as cathode material, MeCN /TBAP
as electrolyte, a divided cell and constant current density in the range 15-25 mA/cm2
, or
working at constant potential between 1.6 and 2.3 V vs Ag/ AgI electrode. The reaction
mechanism seemed to that of the activated halides
Methylation of chloroplast DNA does not affect viability and maternal inheritance in tobacco and may provide a strategy towards transgene containment
We report the integration of a type II restriction-methylase, mFokI, into the tobacco chloroplast genome and we demonstrate that the introduced enzyme effectively directs the methylation of its target sequence in vivo and does not affect maternal inheritance. We further report the transformation of tobacco with an E. coli dcm methylase targeted to plastids and we demonstrate efficient cytosine methylation of the plastid genome. Both adenosine methylation of FokI sites and cytosine methylation of dcm sites appeared phenotypically neutral. The ability to tolerate such plastid genome methylation is a pre-requisite for a proposed plant transgene containment system. In such a system, a chloroplast located, maternally inherited restriction methylase would provide protection from a nuclear-encoded, plastid targeted restriction endonuclease. As plastids are not paternally inherited in most crop species, pollen from such plants would carry the endonuclease transgene but not the corresponding methylase; the consequence of this should be containment of all nuclear transgenes, as pollination will only be viable in crosses to the appropriate transplastomic maternal background
Supervoid Origin of the Cold Spot in the Cosmic Microwave Background
We use a WISE-2MASS-Pan-STARRS1 galaxy catalog to search for a supervoid in
the direction of the Cosmic Microwave Background Cold Spot. We obtain
photometric redshifts using our multicolor data set to create a tomographic map
of the galaxy distribution. The radial density profile centred on the Cold Spot
shows a large low density region, extending over 10's of degrees. Motivated by
previous Cosmic Microwave Background results, we test for underdensities within
two angular radii, , and . Our data, combined with an
earlier measurement by Granett et al 2010, are consistent with a large supervoid with centered at . Such a supervoid, constituting a
fluctuation in the model, is a plausible cause
for the Cold Spot.Comment: 4 pages, 2 figures, Proceedings of IAU 306 Symposium: Statistical
Challenges in 21st Century Cosmolog
HAT-P-50b, HAT-P-51b, HAT-P-52b, and HAT-P-53b: Three Transiting Hot Jupiters and a Transiting Hot Saturn From the HATNet Survey
We report the discovery and characterization of four transiting exoplanets by
the HATNet survey. The planet HAT-P-50b has a mass of 1.35 M_J and a radius of
1.29 R_J, and orbits a bright (V = 11.8 mag) M = 1.27 M_sun, R = 1.70 R_sun
star every P = 3.1220 days. The planet HAT-P-51b has a mass of 0.31 M_J and a
radius of 1.29 R_J, and orbits a V = 13.4 mag, M = 0.98 M_sun, R = 1.04 R_sun
star with a period of P = 4.2180 days. The planet HAT-P-52b has a mass of 0.82
M_J and a radius of 1.01 R_J, and orbits a V = 14.1 mag, M = 0.89 M_sun, R =
0.89 R_sun star with a period of P = 2.7536 days. The planet HAT-P-53b has a
mass of 1.48 M_J and a radius of 1.32 R_J, and orbits a V = 13.7 mag, M = 1.09
M_sun, R = 1.21 R_sun star with a period of P = 1.9616 days. All four planets
are consistent with having circular orbits and have masses and radii measured
to better than 10% precision. The low stellar jitter and favorable R_P/R_star
ratio for HAT-P-51 make it a promising target for measuring the
Rossiter-McLaughlin effect for a Saturn-mass planet.Comment: Submitted to AJ. 20 pages, 9 figures, 5 tables. Data available at
http://hatnet.org
The SARS algorithm: detrending CoRoT light curves with Sysrem using simultaneous external parameters
Surveys for exoplanetary transits are usually limited not by photon noise but
rather by the amount of red noise in their data. In particular, although the
CoRoT spacebased survey data are being carefully scrutinized, significant new
sources of systematic noises are still being discovered. Recently, a
magnitude-dependant systematic effect was discovered in the CoRoT data by Mazeh
& Guterman et al. and a phenomenological correction was proposed. Here we tie
the observed effect a particular type of effect, and in the process generalize
the popular Sysrem algorithm to include external parameters in a simultaneous
solution with the unknown effects. We show that a post-processing scheme based
on this algorithm performs well and indeed allows for the detection of new
transit-like signals that were not previously detected.Comment: MNRAS accepted. 5 pages, 3 figure
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