15,059 research outputs found
CosmoDM and its application to Pan-STARRS data
The Cosmology Data Management system (CosmoDM) is an automated and flexible
data management system for the processing and calibration of data from optical
photometric surveys. It is designed to run on supercomputers and to minimize
disk I/O to enable scaling to very high throughput during periods of
reprocessing. It serves as an early prototype for one element of the
ground-based processing required by the Euclid mission and will also be
employed in the preparation of ground based data needed in the eROSITA X-ray
all sky survey mission. CosmoDM consists of two main pipelines. The first is
the single-epoch or detrending pipeline, which is used to carry out the
photometric and astrometric calibration of raw exposures. The second is the co-
addition pipeline, which combines the data from individual exposures into
deeper coadd images and science ready catalogs. A novel feature of CosmoDM is
that it uses a modified stack of As- tromatic software which can read and write
tile compressed images. Since 2011, CosmoDM has been used to process data from
the DECam, the CFHT MegaCam and the Pan-STARRS cameras. In this paper we shall
describe how processed Pan-STARRS data from CosmoDM has been used to optically
confirm and measure photometric redshifts of Planck-based Sunyaev-Zeldovich
effect selected cluster candidates.Comment: 11 pages, 4 figures. Proceedings of Precision Astronomy with Fully
Depleted CCDs Workshop (2014). Accepted for publication in JINS
Line shifts in the first overtone of DF broadened by HF
Line spectra shifts in HF and in first overtone band of DF induced by HF pressure
MitoCPR: Meticulous Monitoring of Mitochondrial Proteostasis
Mitochondrial protein import stress compromises functioning of the organelles, due to inadequate supply of inner mitochondrial proteins. Weidberg and Amon (2018) describe a new monitoring pathway in budding yeast, which restores mitochondrial function following the clearing of accumulated unfolded pre-transported mitochondrial proteins, by devising a molecular strategy of overexpressing bi-partite-containing mitochondrial proteins
Exploring mitochondrial cholesterol (mChol) signalling for therapeutic intervention in neurological conditions
The pharmacological targeting of cholesterol levels continues to draw interest due to the vast success of therapeutics such as statins in extending life expectancy by modifying the prognosis of diseases associated with the impairment of the lipid metabolism. Advances in our understanding of mitochondrial dysfunction in chronic age‐related diseases of the brain have unveiled an emerging role for mitochondrial cholesterol (mChol) in their pathophysiology, thus delineating an opportunity to provide mechanistic insights and explore strategies of intervention. This review draws attention to novel signalling mechanisms in conditions linked with impaired metabolism associated with impaired handling of cholesterol and its oxided forms (oxysterols) by mitochondria. By emphasising the role of mChol in neurological diseases we here call for novel approaches as well as new means of assessment
The role of interplanetary scattering in western hemisphere large solar energetic particle events
Using high-sensitivity instruments on the ACE spacecraft, we have examined the intensities of O and Fe in 14 large solar energetic particle events whose parent activity was in the solar western hemisphere. Sampling the intensities at low (~273 keV nucleon to the -1) and high (~12 MeV nucleon to the -1) energies, we find that at the same kinetic energy per nucleon, the Fe/O ratio decreases with time, as has been reported previously. This behavior is seen in more than 70% of the cases during the rise to maximum intensity and continues in most cases into the decay phase. We find that for most events if we compare the Fe intensity with the O intensity at a higher kinetic energy per nucleon, the two time-intensity profiles are strikingly similar. Examining alternate scenarios that could produce this behavior, we conclude that for events showing this behavior the most likely explanation is that the Fe and O share similar injection profiles near the Sun, and that scattering in the interplanetary medium dominates the profiles observed at 1 AU
The Sizes of 1720 MHz OH Masers: VLBA and MERLIN Observations of the Supernova Remnants W44 and W28
We have used the NRAO Very Long Baseline Array (VLBA) to image OH(1720 MHz)
masers in the supernova remnants W28 and W44 at a resolution of 40 mas. We also
used MERLIN to observe the same OH(1720 MHz) masers in W44 at a resolution of
290 x 165 mas. All the masers are resolved by these VLBA and MERLIN
observations. The measured sizes range from 50 to 180 mas and yield brightness
temperature estimates from 0.3--20 x 10**8 K. We investigate whether these
measured angular sizes are intrinsic and hence originate as a result of the
physical conditions in the supernova remnant shock, or whether they are scatter
broadened sizes produced by the turbulent ionized gas along the line of sight.
While the current data on the temporal and angular broadening of pulsars,
masers and extragalactic soures toward W44 and W28 can be understood in terms
of scattering, we cannot rule out that these large sizes are intrinsic. Recent
theoretical modeling by Lockett et al. suggests that the physical parameters in
the shocked region are indicative of densities and OH abundances which lead to
estimates of sizes as large as what we measure. If the sizes and structure are
intrinsic, then the OH(1720 MHz) masrs may be more like the OH(1612 MHz) masers
in circumstellar shells than OH masers associated with HII regions. At two
locations in W28 we observe the classical S-shapes in the Stokes V profiles
caused by Zeeman splitting and use it to infer magnetic fields of order 2
milliGauss.Comment: 24 pages, 6 figures, accepted by Ap
Seed populations for large solar particle events of cycle 23
Using high-resolution mass spectrometers on board the Advanced Composition Explorer (ACE), we surveyed the event-averaged ~0.1-60 MeV/nuc heavy ion elemental composition in 64 large solar energetic particle (LSEP) events of cycle 23. Our results show the following: (1) The rare isotope ^3He is greatly enhanced over the corona or the solar wind values in 46% of the events. (2) The Fe/O ratio decreases with increasing energy up to ~10 MeV/nuc in ~92% of the events and up to ~60 MeV/nuc in ~64% of the events. (3) Heavy ion abundances from C-Fe exhibit systematic M/g-dependent enhancements that are remarkably similar to those seen in ^3He-rich SEP events and CME-driven interplanetary (IP) shock events. Taken together, these results confirm the role of shocks in energizing particles up to ~60 MeV/nuc in the majority of large SEP events of cycle 23, but also show that the seed population is not
dominated by ions originating from the ambient corona or the thermal solar wind, as previously
believed. Rather, it appears that the source material for CME-associated large SEP events
originates predominantly from a suprathermal population with a heavy ion enrichment pattern
that is organized according to the ion's mass-per-charge ratio. These new results indicate that
current LSEP models must include the routine production of this dynamic suprathermal seed
population as a critical pre-cursor to the CME shock acceleration process
Calculation of geometric phases in electric dipole searches with trapped spin-1/2 particles based on direct solution of the Schr\"odinger equation
Pendlebury [Phys. Rev. A , 032102 (2004)] were
the first to investigate the role of geometric phases in searches for an
electric dipole moment (EDM) of elementary particles based on Ramsey-separated
oscillatory field magnetic resonance with trapped ultracold neutrons and
comagnetometer atoms. Their work was based on the Bloch equation and later work
using the density matrix corroborated the results and extended the scope to
describe the dynamics of spins in general fields and in bounded geometries. We
solve the Schr\"odinger equation directly for cylindrical trap geometry and
obtain a full description of EDM-relevant spin behavior in general fields,
including the short-time transients and vertical spin oscillation in the entire
range of particle velocities. We apply this method to general macroscopic
fields and to the field of a microscopic magnetic dipole.Comment: 11 pages, 4 figure
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