Modern Crypto-Analysis of Polyalphabetic Ciphers Using a Genetic Algorithm

This project involved implementing a genetic algorithm to help automate the crypto-analysis of the Vigenere cipher

Magnetic fields in nearby galaxies

We describe a recent full-polarization radio continuum survey, performed using the Westerbork Synthesis Radio Telescope (WSRT), of several nearby galaxies in the Spitzer Infrared Nearby Galaxies Survey (SINGS) sample. The WSRT-SINGS survey has been utilized to study the polarized emission and Faraday rotation measures (RMs) in the targets, and reveals an important new observational trend. The azimuthal distribution of polarized flux seems to be intimately related to the kinematic orientation of galaxies, such that in face-on galaxies the lowest level of polarized flux is detected along the kinematic major axis. In highly inclined galaxies, the polarized flux is minimized on both ends of the major axis, and peaks near the minor axis. Using models of various three-dimensional magnetic field geometries, and including the effects of turbulent depolarization in the midplane, we are able to reproduce the qualitative distribution of polarized flux in the target galaxies, its variation with inclination, and the distribution of RMs, thereby constraining the global magnetic field structure in galaxies. Future radio telescope facilities, now being planned and constructed, will have properties making them extremely well-suited to perform vastly larger surveys of this type, and are thereby poised to significantly increase our understanding of the global structure of galactic magnetic fields. We discuss progress that can be made using surveys which will be realized with these new facilities, focusing in particular on the Aperture Tile in Focus (APERTIF) and Australian Square Kilometre Array Pathfinder (ASKAP) telescopes, both based on Focal Plane Array (FPA) designs, which are expected to be particularly useful for wide-field polarization applications.Comment: In proceedings of "Panoramic Radio Astronomy" conference held 2-5 June 2009, Groningen, the Netherlands. 6 pages, 2 figure

Rolling, yawing, and hinge moments produced by rectangular ailerons

Ailerons described in references 1, 2, and 3, are summarized in the form of empirical equations which relate the aileron dimensions and displacements to the rolling, yawing, and hinge moments for pitch angles of 0 and 12 degrees, corresponding to angles of attack of the wings of 4 and 16 degrees, respectively

Effect of aileron displacement on wing characteristics

The effect of aileron displacement on wing characteristics has been investigated for the Clark Y and the U.S.A. 27 wing sections equipped with rectangular ailerons. The airfoils, rectangular in plan, and having a 10 inch chord and 60 inch span, were mounted on a model fuselage

Reusable Centaur study. Volume 1: Executive summary

A study of the Reusable Centaur for use as an initial upper stage with the space shuttle was conducted. The currently operative Centaur stage, with modifications for space shuttle orbiter compatibility and for improved performance, represents a cost effective development solution. The performance needs and available development funds are discussed. The main features of three Reusable Centaur configurations with increasing capability at increasing development costs are summarized

Abstain or die: The development of HIV/AIDS policy in Botswana

This paper traces the development of policies dealing with HIV/AIDS in Botswana from their beginning in the late 1980s to the current programme to provide population-wide anti-retroviral therapy (ARV). Using a variety of source material, including long-term ethnographic research, it seeks to account for the failure of Western-inspired approaches in dealing with the pandemic. It does this by looking at the cultural and institutional features that have created resistance to the message and inhibited effective implementation. The negative response to the first educational campaign stressing condom use is described and contextualized in terms of Tswana ideas of morality and illness. Nor, as was initially expected, did the introduction of free ARV therapy operate to break the silence and stigma that had developed around the disease. Take-up was very slow, and did not operate to encourage widespread testing. In 2003, key policymakers in Botswana began to argue for a break with the AIDS ‘exceptionalism’ position, with its emphasis on voluntarism, confidentiality and the human rights of patients. This resulted in routine testing being introduced in 2004. This links to a major argument running through the paper which is that the failure of policy cannot be attributed solely to the nature of local populations. Western cultural assumptions about ‘good practice’ also require critical examination

Magnetic fields on a wide range of scales in star-forming galaxies

A key ingredient in the evolution of galaxies is the star formation cycle. Recent progress in the study of magnetic fields is revealing the close connection between star formation and its effect on the small-scale structure in the magnetized interstellar medium (ISM). In this contribution we describe how the modern generation of radio telescopes is being used to probe the physics of the ISM through sensitive multiwavelength surveys of gas and magnetic fields, from the inner star forming disk and outward into the galaxy outskirts where large-scale magnetic fields may also play a key role. We highlight unique pioneering efforts towards performing and scientifically exploiting large-scale surveys of the type that the SKA will undertake routinely. Looking to the future, we describe plans for using the Square Kilometre Array (SKA) and its pathfinders to gain important new insights into the cosmic history of galaxy evolution.Comment: 12 pages, 3 figures, Proceedings of the conference "The many facets of extragalactic radio surveys: towards new scientific challenges", PoS(EXTRA-RADSUR2015)011, eds. I Prandoni & R. Morgant

The governance of public bodies in times of austerity

Private sector governance arrangements have been imported into UK public bodies under the influence of New Public Management reforms. This paper draws on a cohort study of 14 public bodies to assess the appropriateness of this practice and the impact of fiscal austerity during the study period of 2010–16. Based on multiple sources, including interviews with Chairs and Chief Executives, it shows that, though similar to private corporate Boards in appearance, public Boards are often excluded from the strategy role. They are also vulnerable to the elastic definition of policy over which Ministers assert dominance, thereby blurring accountability. It demonstrates the tension between vertical accountability to government principals and horizontal accountability to stakeholders. During the study window, public bodies were abolished, broken up, merged, reconfigured or taken back into core government, as the UK Government imposed austerity measures to reduce the size of the fiscal deficit and to diminish government roles in delivery, financing and regulation of public services. Surviving public bodies in the study suffered deep budget cuts and less autonomy from central control. These findings are interpreted as evidence of the re-territorialisation of the UK public sector, with accruals accounting and accounting consolidation practices playing a facilitating role

Feedback in Galaxy Formation

I review the outstanding problems in galaxy formation theory, and the role of feedback in resolving them. I address the efficiency of star formation, the galactic star formation rate, and the roles of supernovae and supermassive black holes.Comment: To appear in the proceedings of IAU Symposium 277, Burkina Faso, December 2010, Tracing the Ancestry of Galaxies (on the Land of our Ancestors), C. Carignan, F. Combes \& K. Freeman, ed