XMM-Newton observations of SNR 1987A. II. The still increasing X-ray light curve and the properties of Fe K lines

Aims. We report on the recent observations of the supernova remnant SNR 1987A in the Large Magellanic Cloud with XMM-Newton. Carefully monitoring the evolution of the X-ray light curve allows to probe the complex circumstellar medium structure observed around the supernova progenitor star. Methods. We analyse all XMM-Newton observations of SNR 1987A from January 2007 to December 2011, using data from the EPIC-pn camera. Spectra from all epochs are extracted and analysed in a homogeneous way. Using a multi-shock model to fit the spectra across the 0.2-10 keV band we measure soft and hard X-ray fluxes with high accuracy. In the hard X-ray band we examine the presence and properties of Fe K ines. Our findings are interpreted in the framework of a hydrodynamics-based model. Results. The soft X-ray flux of SNR 1987A continuously increased in the recent years. Although the light curve shows a mild flattening, there is no sudden break as reported in an earlier work, a picture echoed by a revision of the Chandra light curve. We therefore conclude that material in the equatorial ring and out-of-plane HII regions are still being swept-up. We estimate the thickness of the equatorial ring to be at least 4.5x10^16 cm (0.0146 pc). This lower limit will increase as long as the soft X-ray flux has not reached a turn-over. We detect a broad Fe K line in all spectra from 2007 to 2011. The widths and centroid energies of the lines indicate the presence of a collection of iron ionisation stages. Thermal emission from the hydrodynamic model does not reproduce the low-energy part of the line (6.4-6.5 keV), suggesting that fluorescence from neutral and/or low ionisation Fe might be present.Comment: 4 pages, 3 figures, 2 tables. Accepted for publication in Astronomy and Astrophysic

Avoiding Wireheading with Value Reinforcement Learning

How can we design good goals for arbitrarily intelligent agents? Reinforcement learning (RL) is a natural approach. Unfortunately, RL does not work well for generally intelligent agents, as RL agents are incentivised to shortcut the reward sensor for maximum reward -- the so-called wireheading problem. In this paper we suggest an alternative to RL called value reinforcement learning (VRL). In VRL, agents use the reward signal to learn a utility function. The VRL setup allows us to remove the incentive to wirehead by placing a constraint on the agent's actions. The constraint is defined in terms of the agent's belief distributions, and does not require an explicit specification of which actions constitute wireheading.Comment: Artificial General Intelligence (AGI) 201

Inclusive Branding Strategies for Domestic Violence Agencies: Embracing Opportunities to Reach and Better Serve Male-Identified Survivors

Successful strategies for branding that are inclusive to male-identified survivors were identified in this qualitative study through semi-structured interviews with leaders from six domestic violence agencies across the United States: four represented traditional domestic violence agencies and two represented specialized agencies with expertise in providing services to non-traditional survivors. The strategic implementation of 1) inclusive language, 2) visual diversity, 3) community outreach, and 4) communication channels emerged as successful strategies in branding in an inclusive way for male-identified survivors. The implementation of these successful strategies provides the opportunity for domestic violence agencies to create an inclusive environment for male-identified survivors, and would contribute to a paradigm shift in how domestic violence is viewed

An evaluation of the Klimov-Shamir keystream generator

Stream ciphers are valuable in applications where efficiency and security are both needed. Linear feedback shift register sequences have been the mainstay of stream ciphers in the past. However, Alexander Klimov and Adi Shamir recently proposed a class of invertible T-functions as a possible source of cryptographic building blocks for stream ciphers. In particular, they present the mapping xf = x + (x² V 5) (mod 2[superscript n]) which is a permutation with a single cycle modulo 2[superscript n] for any n. We discuss traditional stream cipher constructions and the desired properties of sequences produced by pseudorandom keystream generators. We then utilize these desired properties to analyze the aforementioned Klimov-Shamir keystream generator. Finally, we propose a possible construction for a keystream generator that combines a traditional stream cipher construction and the function proposed by Klimov and Shamir in order to produce a keystream that adheres to the desired properties we set forth

Crafty Sailors, Unruly Seas: Margaret Cohen’s Oceanic History of the Novel

The Novel and the Sea by Margaret Cohen. Translation/Transnation, edited by Emily Apter. Princeton, NJ: University of Princeton Press, 2010. Pp. xiii + 306, 30 illustrations. $39.50 cloth

The Role of Presley in Norris\u27 The Octopus

A monograph presented to the faculty of the Department of English at Morehead State University in partial fulfillment of the requirements for the Degree of Master of Arts by Dewey D. Lawson in June of 1972

Supernova Remnant Evolution in Wind Bubbles: A Closer Look at Kes 27

Massive Stars (> 8 solar masses) lose mass in the form of strong winds. These winds accumulate around the star, forming wind-blown bubbles. When the star explodes as a supernova (SN), the resulting shock wave expands within this wind-blown bubble, rather than the interstellar medium. The properties of the resulting remnant, its dynamics and kinematics, the morphology, and the resulting evolution, are shaped by the structure and properties of the wind-blown bubble. In this article we focus on Kes 27, a supernova remnant (SNR) that has been proposed by Chen et al (2008) to be evolving in a wind-blown bubble, explore its properties, and investigate whether the properties could be ascribed to evolution of a SNR in a wind-blown bubble. Our initial model does not support this conclusion, due to the fact that the reflected shock is expanding into much lower densities.Comment: 5 pages, 3 figures. Revised version submitted to High Energy Density Physics. To be published in a special issue of the proceedings of the 2012 HEDLA conferenc

Concanavalin A-Binding Enzymes of Crotalus scutulatus scutulatus Venom

Crotalus scutulatus scutulatus crude venom was separated into two fractions by Concanavalin A Sepharose 4B affinity chromatography. The proteins binding to Con A exhibited phosphomonoesterase (orthophosphoric monoester phosphohydrolase EC 3.1.3.2), phosphodiesterase, 5\u27-nucleotidase (5\u27-ribonucleotide phosphohydrolase EC 3.1.3.5), phospholipase A(phosphatidate 2-acylhydrolase EC 3.1.1 .4), hyaluronidase (hyaluronate glycanohydrolase EC 3.2.1 d), N-benzoyl-L-arginine ethyl esterase, p-toluenesulfonyl-L-arginine methyl esterase, L-amino acid oxidase (L-amino acid: 02 oxidoreductase [deaminating] EC 1.4.3.2), and caseinolytic activities. Thrombin-like and NAD nucleosidase (5\u27-ribonucleotide phosphohydrolase EC 3.1.3.5) activities were not observed. The crude venom and the fraction containing the glycoproteins which bound to Con A were fractionated by DEAE Sephadex A-50 ion exchange chromatography. Each of these samples yielded fractions having caseinolytic activities