Red Supergiants in the Andromeda Galaxy (M31)

Red supergiants are a short-lived stage in the evolution of moderately massive stars (10-25Mo), and as such their location in the H-R diagram provides an exacting test of stellar evolutionary models. Since massive star evolution is strongly affected by the amount of mass-loss a star suffers, and since the mass-loss rates depend upon metallicity, it is highly desirable to study the physical properties of these stars in galaxies of various metallicities. Here we identify a sample of red supergiants in M31 (the most metal-rich of the Local Group galaxies) and derive their physical properties by fitting MARCS atmosphere models to moderate resolution optical spectroscopy, and from V-K photometry.Comment: Accepted for publication in the Astrophysical Journa

Bull’s-Eye: How the 81ST Texas Legislature Nearly Got It Right on Campus Carry, and the 82ND Should Still Hit the X-Ring

This Comment examines recent legislative proposals for reform of the current limitations on concealed handgun licensees in Texas and their inability to readily defend themselves or others against armed attackers while on the premises of institutions of higher learningboth public and private-in this state.8 It suggests that the modifications to current law, as proposed by 2009\u27s Senate Bill 1164, set clear workable boundaries between balancing campus safety versus reduced intellectual freedom, and the necessary evolution of the law to answer the evils of our times. Part I of this Comment frames the seriousness of the score of mass school shootings which have occurred across the United States during the past few decades within a context that legal academics may no longer conscientiously ignore. A school shooting on a law school campus should drive home the fact that no geographical area, nor level of esteem, can protect an institution from attack by a motivated, armed criminal, already willing to ignore the law. Part II of this Comment provides background information and the historical context of gun ownership rights in Texas, including the evolution of this state\u27s legal framework for addressing public violence by allowing citizens to bear arms (whether concealed or not). Part III presents a detailed review of the current concealed handgun licensing statutes in Texas, including what is required of an individual to obtain such a license, as well as the limitations placed upon that licensee with respect to where he may and may not have his gun under authority of the license. Part IV summarizes the current state of concealed carry laws in the forty-nine states other than Texas, explaining some of the nuances and development of differing statutory schemes. Part V of this Comment examines the school-shooting phenomenon as it occurs on the campuses of institutions of higher learning, including the reasons why these mass attacks occur, where, and how they do, as well as the disincentive value of armed students and faculties. Part VI discusses S.B. 1164 as proposed and identifies elements within it in an attempt to improve on the existing doctrine, including opposition against the legislation by the academic community, as well as considerations for institutions that prohibit otherwise lawful carry, which results in a shooting death. Finally, Part VII addresses some of the arguments for and against adoption of this legislation, including policy considerations, statistical analyses, and rationales. The next time Concealed Carry reform resurfaces in Austin will be an opportunity to improve on the rights of Texas citizens to defend themselves from armed assailants where they would otherwise be most vulnerable: the shooting galleries we call classrooms

Quantifying slope-channel coupling in an active gully and fan complex at Tarndale, Waipaoa catchment, New Zealand

Two RIEGL LMS‐Z420i scanner surveys (November 2007 and November 2008) of the Tarndale Gully complex and its associated fan were used to generate a digital elevation model (DEM) of difference in order to quantify gully‐fan‐channel connectivity. The Te Weraroa Stream, into which the first order Tarndale system feeds, is buffered from sediment generated by the gully complex by a fan. Sediment yields and the role of the fan in buffering Te Weraroa Stream are inferred from the TLS of the entire complex. DEM analysis suggests that c.25% of material derived from the gully is buffered from the stream by being stored in the fan. This figure was applied to fan behaviour since December 2004, mapped on nine successive occasions using detailed GPS surveys to get a longer‐term picture of sediment supply within the system and appraise a qualitative assessment of connectivity constructed on the basis of fan behaviour alone

"We are GREAT Britain": British newspaper narratives during the London 2012 Olympic Games

British newspaper narratives were examined during the 2012 London Olympic Games to discern how the British press promoted specific “narratives of the nation.” For the London-based British press, the home Olympics became the ideal medium not only to sell newspapers and electronic format subscriptions, but also to (re)present their views on Britain and what it stood for. Using a qualitative textual analysis methodology, this study drew on Anderson’s theory of the “imagined community” and Edmunds and Turner’s concepts of benign and malign nationalism to provide insights about how Britishness was framed. For a country struggling to shake off the economic recession, early narratives about the Games were imbued with concerns about the escalating costs of hosting the Games and fears of terrorism. However, the critical early tone of British newspaper narratives was supplanted with uplifting, inspirational stories about the unprecedented success of Team GB athletes. This provided British journalists with an opportunity to reengineer Britishness to reinforce some traditional values and inject some new inclusive ones. Although at times, complex, contested and contradictory, the narratives generally linked the internationalism of the Olympics with a progressive, benign version of Britishness that emphasized inclusion, tolerance, and creativity and, at least temporarily, redefined how Britain regarded itself and was viewed.</jats:p

Digital receiver study and implementation

Computer software was developed which makes it possible to use any general purpose computer with A/D conversion capability as a PSK receiver for low data rate telemetry processing. Carrier tracking, bit synchronization, and matched filter detection are all performed digitally. To aid in the implementation of optimum computer processors, a study of general digital processing techniques was performed which emphasized various techniques for digitizing general analog systems. In particular, the phase-locked loop was extensively analyzed as a typical non-linear communication element. Bayesian estimation techniques for PSK demodulation were studied. A hardware implementation of the digital Costas loop was developed

Test of nuclear level density inputs for Hauser-Feshbach model calculations

The energy spectra of neutrons, protons, and alpha-particles have been measured from the d+59Co and 3He+58Fe reactions leading to the same compound nucleus, 61$Ni. The experimental cross sections have been compared to Hauser-Feshbach model calculations using different input level density models. None of them have been found to agree with experiment. It manifests the serious problem with available level density parameterizations especially those based on neutron resonance spacings and density of discrete levels. New level densities and corresponding Fermi-gas parameters have been obtained for reaction product nuclei such as 60Ni,60Co, and 57Fe

Evidence for a fundamental stellar upper mass limit from clustered star formation

The observed masses of the most massive stars do not surpass about 150Msun. This may either be a fundamental upper mass limit which is defined by the physics of massive stars and/or their formation, or it may simply reflect the increasing sparsity of such very massive stars so that observing even higher-mass stars becomes unlikely in the Galaxy and the Magellanic Clouds. It is shown here that if the stellar initial mass function (IMF) is a power-law with a Salpeter exponent (alpha=2.35) for massive stars then the richest very young cluster R136 seen in the Large Magellanic Cloud (LMC) should contain stars with masses larger than 750Msun. If, however, the IMF is formulated by consistently incorporating a fundamental upper mass limit then the observed upper mass limit is arrived at readily even if the IMF is invariant. An explicit turn-down or cutoff of the IMF near 150Msun is not required; our formulation of the problem contains this implicitly. We are therefore led to conclude that a fundamental maximum stellar mass near 150Msun exists, unless the true IMF has alpha>2.8.Comment: MNRAS, accepted, 6 page

Sersiclets - A Matched Filter Extension of Shapelets for Weak Lensing Studies

The precision study of dark matter using weak lensing by large scale structure is strongly constrained by the accuracy with which one can measure galaxy shapes. Several methods have been devised but none have demonstrated the ability to reach the level of precision required by future weak lensing surveys. In this Letter we explore new avenues to the existing Shapelets approach, combining a priori knowledge of the galaxy profile with the power of orthogonal basis function decomposition. This Letter discusses the new issues raised by this matched filter approach and proposes promising alternatives to shape measurement techniques. In particular it appears that the use of a matched filter (e.g. Sersic profile) restricted to elliptical radial fitting functions resolves several well known Shapelet issues.Comment: 6 pages, 6 figures. MNRAS Accepte

All two dimensional links are null homotopic

We show that any number of disjointly embedded 2-spheres in 4-space can be pulled apart by a link homotopy, ie, by a motion in which the 2-spheres stay disjoint but are allowed to self-intersect.Comment: 18 pages. Published copy, also available at http://www.maths.warwick.ac.uk/gt/GTVol3/paper10.abs.htm