Distance Determination To Eight Galaxies Using Expanding Photosphere Method

Type IIP supernovae are recognized as independent extragalactic distance indicators, however, keeping in view of the diverse nature of their observed properties as well as the availability of good quality data, more and newer events need to be tested for their applicability as a reliable distance indicators. We use early photometric and spectroscopic data of eight type-IIP SNe to derive distances to their host galaxies using the expanding photosphere method (EPM). For five of these, EPM is applied for the first time. In this work, we improved EPM application by using SYNOW estimated velocities and by semi-deconvolving the broadband filter responses while deriving color temperatures and black-body angular radii. We find that the derived EPM distances are consistent with that derived using other redshift independent methods.Comment: 11 Pages, 13 Figures, 6 Tables. Accepted to Ap

The Maximum Exposure Problem

Given a set of points P and axis-aligned rectangles R in the plane, a point p in P is called exposed if it lies outside all rectangles in R. In the max-exposure problem, given an integer parameter k, we want to delete k rectangles from R so as to maximize the number of exposed points. We show that the problem is NP-hard and assuming plausible complexity conjectures is also hard to approximate even when rectangles in R are translates of two fixed rectangles. However, if R only consists of translates of a single rectangle, we present a polynomial-time approximation scheme. For general rectangle range space, we present a simple O(k) bicriteria approximation algorithm; that is by deleting O(k^2) rectangles, we can expose at least Omega(1/k) of the optimal number of points

Energy dependence of pbar/p ratio in p+p collisions

We have compiled the experimentally measured pbar/p ratio at midrapidity in p+p collisions from \sqrt{s} = 23 to 7000 GeV and compared it to various mechanisms of baryon production as implemented in PYTHIA, PHOJET and HIJING/B-Bbar models. For the models studied with default settings, PHOJET has the best agreement with the measurements, PYTHIA gives a higher value for \sqrt{s} < 200 GeV and the ratios from HIJING/B-Bbar are consistently lower for all the \sqrt{s} studied. Comparison of the data to different mechanisms of baryon production as implemented in PYTHIA shows that through a suitable tuning of the suppression of diquark-antidiquark pair production in the color field relative to quark-antiquark production and allowing the diquarks to split according to the popcorn scheme gives a fairly reasonable description of the measured pbar/p ratio for \sqrt{s} < 200 GeV. Comparison of the beam energy dependence of the pbar/p ratio in p+p and nucleus-nucleus (A+A) collisions at midrapidity shows that the baryon production is significantly more for A+A collisions relative to p+p collisions for \sqrt{s} < 200 GeV. We also carry out a phenomenological fit to the y_beam dependence of the pbar/p ratio.Comment: 5 pages and 5 figures. Accepted in Physical Review

Efficient Algorithms for k-Regret Minimizing Sets

A regret minimizing set Q is a small size representation of a much larger database P so that user queries executed on Q return answers whose scores are not much worse than those on the full dataset. In particular, a k-regret minimizing set has the property that the regret ratio between the score of the top-1 item in Q and the score of the top-k item in P is minimized, where the score of an item is the inner product of the item\u27s attributes with a user\u27s weight (preference) vector. The problem is challenging because we want to find a single representative set Q whose regret ratio is small with respect to all possible user weight vectors. We show that k-regret minimization is NP-Complete for all dimensions d>=3, settling an open problem from Chester et al. [VLDB 2014]. Our main algorithmic contributions are two approximation algorithms, both with provable guarantees, one based on coresets and another based on hitting sets. We perform extensive experimental evaluation of our algorithms, using both real-world and synthetic data, and compare their performance against the solution proposed in [VLDB 14]. The results show that our algorithms are significantly faster and scalable to much larger sets than the greedy algorithm of Chester et al. for comparable quality answers

Effect of wheat seed dressing fungicides, botanicals and bio-control agent on Karnal bunt incidence in natural condition

In this study the efficacy of four fungicides, three botanicals and one bio-control agent under field conditions revealed that all the treatments gave reduction of Karnal bunt over check at significant level (P=0.05). Maximum disease control was achieved with Tilt 25EC (48.72%) followed by Bavistin 50WP (47.08 %), Vitavax 75WP (45.30%) and Raxil 2DS (37.61%). Among botanicals L. camara was adjudged best as it gave 41.88 per cent disease control. However, seed treatment of T. viride (Ecoderma) resulted in 28.21 percent disease control. In all treatments over all disease control level was ranged between 28.21 to 48.72 per cent. For effective disease management, source of primary inoculum must be destroy. Primary inoculum of Karnal bunt is present in seed. There-fore, eco-friendly seed treatment of wheat is necessary process for diseases management

The Study of Physical Parameters of Pb Modified Germanate Chalcogenide Glass

In the present paper we have studied the physical properties of Se-Sn-Pb chalcogenide material. The necessary physical parameters which have important role in determining the structure and strength of the material viz. constraints, coordination number, glass transition temperature etc. has been calculated. The decreasing trend has been found in cohesive energy, heat of atomization and mean bond energy. The glass transition has been studied using the Tichy-Ticha approach which also decreases. The decrease in these physical parameters is due to the increase of ionic character in the material. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3559