On associating Fast Radio Bursts with afterglows

A radio source that faded over six days, with a redshift of $z\approx0.5$ host, has been identified by Keane et al. (2016) as the transient afterglow to a fast radio burst (FRB 150418). We report follow-up radio and optical observations of the afterglow candidate and find a source that is consistent with an active galactic nucleus. If the afterglow candidate is nonetheless a prototypical FRB afterglow, existing slow-transient surveys limit the fraction of FRBs that produce afterglows to 0.25 for afterglows with fractional variation, $m=2|S_1-S_2|/(S_1+S_2)\geq0.7$, and 0.07 for $m\geq1$, at 95% confidence. In anticipation of a barrage of bursts expected from future FRB surveys, we provide a simple framework for statistical association of FRBs with afterglows. Our framework properly accounts for statistical uncertainties, and ensures consistency with limits set by slow-transient surveys.Comment: Accepted version (ApJL

Wide radio beams from γ-ray pulsars

We investigate the radio and γ-ray beaming properties of normal and millisecond pulsars (MSPs) by selecting two samples from the known populations. The first, Sample G, contains pulsars which are detectable in blind searches of γ-ray data from the Fermi Large Area Telescope. The second, Sample R, contains pulsars detectable in blind radio searches which have spin-down luminosities Ė>10^(34) erg s^(–1). We analyze the fraction of the γ-ray-selected Sample G which have detectable radio pulses and the fraction of the radio-selected Sample R which have detectable γ-ray pulses. Twenty of our 35 Sample G pulsars have already observed radio pulses. This rules out low-altitude polar-cap beaming models if, as is currently believed, γ-ray beams are generated in the outer magnetosphere and are very wide. We further find that, for the highest-Ė pulsars, the radio and γ-ray beams have comparable beaming factors, i.e., the beams cover similar regions of the sky as the star rotates. For lower-Ė γ-ray emitting pulsars, the radio beams have about half of the γ-ray sky coverage. These results suggest that, for high-Ė young and MSPs, the radio emission originates in wide beams from regions high in the pulsar magnetosphere, probably close to the null-charge surface and to the γ-ray emitting regions. Furthermore, it suggests that for these high-Ė pulsars, as in the γ-ray case, features in the radio profile represent caustics in the emission beam pattern

STUDY ON THE CHEMICAL CONSTITUENTS OF THE ESSENTIAL OIL FROM NYCTANTHES ARBOR-TRISTIS AND ITS MOLECULAR DOCKING STUDIES

Objectives: The objectives of this study were to determine the chemical composition of the essential oil obtained from the flowers of Nyctanthes arbor-tristis (NAT) and to carryout molecular docking studies against three bacterial proteins to study the mechanism of the antibacterial activity. Methods: The essential oil was obtained from the flowers of NAT by hydrodistillation and the chemical composition was determined by gas chromatography–mass spectrometry analysis. Docking study was carried out for 14 compounds identified from NAT against three bacterial proteins 1UAG, 3TYE, and 3UDI. Results: Fourteen compounds were identified in the essential oil. 1-octanol (74.81%) is the predominant compound followed by phytol (6.80%), bis (2-ethylhexyl) phthalate (5.88%), and eucarvone (4.23%). Many compounds are similar to that of the essential oil from jasmine. Among the 14 compounds identified, 7,9-di-tert-butyl-1-oxaspiro (4,5) deca-6,9-diene-2,8-dione interacted well with 1UAG and 3TYE and showed binding scores of −8.9 and −7.2 K Cal/mol, respectively, involving hydrophilic and hydrophobic interactions. With the protein 3UDI, the compound eucarvone exhibited a binding score of −7.1 K Cal/mol. Conclusion: The similarities between the essential oil constituents of flowers the two plants NAT and jasmine. Therefore, it could be concluded that NAT flowers of Coimbatore are a good source of fragrance for cosmetic industry and as an antibacterial agent

Nitric Oxide Coordinates Cell Proliferation and Cell Movements During Early Development of Xenopus

The establishment of a vertebrate body plan during embryogenesis is achieved through precise coordination of cell proliferation and morphogenetic cell movements. Here we show that nitric oxide (NO) suppresses cell division and facilitates cell movements during early development of Xenopus, such that inhibition of NO synthase (NOS) increases proliferation in the neuroectoderm and suppresses convergent extension in the axial mesoderm and neuroectoderm. NO controls cell division and cell movement through two separate signaling pathways. Both rely on RhoA-ROCK signaling but can be distinguished by the involvement of either guanylate cyclase or the planar cell polarity regulator Dishevelled. Through the cGMP-dependent pathway, NO suppresses cell division by negatively regulating RhoA and controlling the nuclear distribution of ROCK and p21WAF1. Through the cGMP-independent pathway, NO facilitates cell movement by regulating the intracellular distribution and level of Dishevelled and the activity of RhoA, thereby controlling the activity of ROCK and regulating actin cytoskeleton remodeling and cell polarization. Concurrent control by NO helps ensure that the crucial processes of cell proliferation and morphogenetic movements are coordinated during early development

Critical currents in vicinal YBa2_2Cu3_3O7−δ_{7-\delta} films

Most measurements of critical current densities in YBa$_2$Cu$_3$O$_{7-\delta}$ thin films to date have been performed on films where the \textit{c}-axis is grown normal to the film surface. With such films, the analysis of the dependence of $j_c$ on the magnetic field angle is complex. The effects of extrinsic contributions to the angular field dependence of $j_c$, such as the measurement geometry and disposition of pinning centres, are convoluted with those intrinsically due to the anisotropy of the material. As a consequence of this, it is difficult to distinguish between proposed FLL structure models on the basis of angular critical current density measurements on \textit{c}-axis films. Films grown on mis-cut (vicinal) substrates have a reduced measurement symmetry and thus provide a greater insight into the critical current anisotropy. In this paper previous descriptions of the magnetic field angle dependence of $j_c$ in YBa$_2$Cu$_3$O$_{7-\delta}$ are reviewed. Measurements on YBa$_2$Cu$_3$O$_{7-\delta}$ thin films grown on a range of vicinal substrates are presented and the results interpreted in terms of the structure and dimensionality of the FLL in YBa$_2$Cu$_3$O$_{7-\delta}$. There is strong evidence for a transition in the structure of the flux line lattice depending on magnetic field magnitude, orientation and temperature. As a consequence, a simple scaling law can not, by itself, describe the observed critical current anisotropy in YBa$_2$Cu$_3$O$_{7-\delta}$. The experimentally obtained $j_c(\theta)$ behaviour of YBCO is successfully described in terms of a kinked vortex structure for fields applied near parallel to the \textit{a-b} planes.Comment: 10 pages, 12 figures, Submitted to PR

ANALYSIS OF DERIVATIVES – A CASE STUDY

Derivatives are the products whose value is derived from the value of one or more basic variables, called bases (underlying asset, index, or reference rate), in a contractual manner. The underlying asset can be equity, forex, commodity or any other asset. In precise we can say that Derivatives are financial contracts whose value/price is dependent on the behavior of the price of one or more basic underlying assets (often simply known as underlying). The present study is an attmept to analyse the performance of futures and options of NCL Industries Ltd