474 research outputs found
Measuring the Hubble constant with Type Ia supernovae as near-infrared standard candles
The most precise local measurements of rely on observations of Type Ia
supernovae (SNe Ia) coupled with Cepheid distances to SN Ia host galaxies.
Recent results have shown tension comparing to the value inferred from
CMB observations assuming CDM, making it important to check for
potential systematic uncertainties in either approach. To date, precise local
measurements have used SN Ia distances based on optical photometry, with
corrections for light curve shape and colour. Here, we analyse SNe Ia as
standard candles in the near-infrared (NIR), where intrinsic variations in the
supernovae and extinction by dust are both reduced relative to the optical.
From a combined fit to 9 nearby calibrator SNe with host Cepheid distances from
Riess et al. (2016) and 27 SNe in the Hubble flow, we estimate the absolute
peak magnitude mag and
(statistical) 2.7 (systematic) km s Mpc. The 2.2
statistical uncertainty demonstrates that the NIR provides a compelling avenue
to measuring SN Ia distances, and for our sample the intrinsic (unmodeled) peak
magnitude scatter is just 0.10 mag, even without light curve shape or
colour corrections. Our results do not vary significantly with different sample
selection criteria, though photometric calibration in the NIR may be a dominant
systematic uncertainty. Our findings suggest that tension in the competing
distance ladders is likely not a result of supernova systematics that
could be expected to vary between optical and NIR wavelengths, like dust
extinction. We anticipate further improvements in with a larger
calibrator sample of SNe Ia with Cepheid distances, more Hubble flow SNe Ia
with NIR light curves, and better use of the full NIR photometric data set
beyond simply the peak -band magnitude.Comment: 13 pages, replaced to match published version in A&A, code available
at https://github.com/sdhawan21/irh
Exploiting Data Parallelism in the yConvex Hypergraph Algorithm for Image Representation using GPGPUs
To define and identify a region-of-interest (ROI) in a digital image, the
shape descriptor of the ROI has to be described in terms of its boundary
characteristics. To address the generic issues of contour tracking, the yConvex
Hypergraph (yCHG) model was proposed by Kanna et al [1]. In this work, we
propose a parallel approach to implement the yCHG model by exploiting massively
parallel cores of NVIDIA's Compute Unified Device Architecture (CUDA). We
perform our experiments on the MODIS satellite image database by NASA, and
based on our analysis we observe that the performance of the serial
implementation is better on smaller images, but once the threshold is achieved
in terms of image resolution, the parallel implementation outperforms its
sequential counterpart by 2 to 10 times (2x-10x). We also conclude that an
increase in the number of hyperedges in the ROI of a given size does not impact
the performance of the overall algorithm.Comment: 1 page, 1 figure published in Proceedings of the 27th ACM
International Conference on Supercomputing, ICS 2013, Eugene, Oregon, US
OGLE-TR-56
In early 2003 our team announced the discovery of the second extrasolar transiting planet, around the faint star OGLE-TR-56 (V = 16.6), based on the detection of small changes in the radial velocity of the primary. The star was originally identified as a candidate by the OGLE team from the shallow and periodic dips in its brightness. We present here new precise radial velocity measurements that confirm the variation measured earlier, supporting the conclusion that the companion is indeed a planet. Additional photometric observations are also available, which combined with the spectroscopy yield improved parameters (mass and radius) for the planet
MOLECULAR DOCKING STUDY OF NEUROPROTECTIVE PLANT-DERIVED BIOMOLECULES IN PARKINSON'S DISEASE
Objective: The objective of this study was to explore the therapeutic role of biomolecules in targeting the altered expression of Parkin in PD pathogenesis.Methods: We employed various in silico tools such as drug-likeness parameters, namely, Lipinski filter analysis, Muscle tool for phylogenetic analysis, Castp Server for active site prediction, molecular docking studies using AutoDock 4.2.1 and LIGPLOT1.4.5 were carried out.Results: Our results show that neuroprotective activity of Quercetin to be most effective and can provide their possible clinical relevance in PD. Further, initial screenings of the molecules were done based on Lipinski's rule of five. CastP server used to predict the ligand binding site suggests that this protein can be utilized as a potential drug target. Finally, we have found Quercetin to be most effective amongst four biomolecules in modulating Parkin based on minimum inhibition constant, Ki and highest negative free energy of binding with the maximum interacting surface area in a course of docking studies.Conclusion: This research could provide a potential therapeutic window for the treatment of PD
AN IN SILICO STUDY OF NARINGENIN-MEDIATED NEUROPROTECTION IN PARKINSON'S DISEASE
  Objective: Naringenin is a dietary biomolecule with broad spectrum of activities which protects neurons from various neurotoxic insults and improves cognition and motor function in neurodegenerative diseases. DJ-1 has both, ubiquitin E3 ligase as well as chaperonic activity, and loss of ubiquitin E3 ligase activity of DJ-1 has been found to be associated with familial Parkinson's disease (PD). Naringenin induced E3 ligase activity of DJ-1 which can have possible clinical relevance in PD.Methods: Various in silico parameters such as phylogenetic analysis, homology modeling, active site prediction, and molecular docking studies using AutoDock 4.2.1 and LIGPLOT1.4.5 were carried out.Results: Three-dimensional structure of DJ-1 was generated and Ramachandran plot was obtained for quality assessment. RAMPAGE displayed 99.5% of residues in the most favored regions. 0% residues in additionally allowed and 0.5% disallowed regions of DJ-1 protein. Further, initial screenings of the molecules were done based on Lipinski's rule of five. CastP server used to predict the ligand binding site suggests that this protein can be utilized as a potential drug target. Finally, we have found naringenin to be most effective among four biomolecules in modulating DJ-1 based on minimum inhibition constant, Ki, and highest negative free energy of binding with maximum interacting surface area in the course of docking studies.Conclusion: Our study suggests that based on different in silico parameters and molecular docking studies, naringenin can provide a new avenue for PD therapeutics
A Conceptual Architecture for a Quantum-HPC Middleware
Quantum computing promises potential for science and industry by solving
certain computationally complex problems faster than classical computers.
Quantum computing systems evolved from monolithic systems towards modular
architectures comprising multiple quantum processing units (QPUs) coupled to
classical computing nodes (HPC). With the increasing scale, middleware systems
that facilitate the efficient coupling of quantum-classical computing are
becoming critical. Through an in-depth analysis of quantum applications,
integration patterns and systems, we identified a gap in understanding
Quantum-HPC middleware systems. We present a conceptual middleware to
facilitate reasoning about quantum-classical integration and serve as the basis
for a future middleware system. An essential contribution of this paper lies in
leveraging well-established high-performance computing abstractions for
managing workloads, tasks, and resources to integrate quantum computing into
HPC systems seamlessly.Comment: 12 pages, 3 figure
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