Improving Photometry and Astrophotography by Eliminating Dark Frames and Flat Fields

I report on the efforts to improve the dark frames and flat fielding procedure for the charged-coupled device (CCD) camera for the Celestron C14 telescope at the UNH observatory. Dark frames are images taken while the shutter of the camera is closed so that only electronic and dark noise and other internal inconsistencies are recorded. These are important because they allow astronomers to subtract out interference from dark current. Additionally, flat fields are images of the entire field of the telescope so that the brightness in the pixels of the telescope’s field of view is uniform. Flat fields are vital since they provide a consistent illumination for all photos taken from the camera. With the combination of these two features, I was able to optimize the clarity of the telescope’s pictures and show through photometry how the new calibrated images appear in comparison to images prior to the calibration. Overall, these enhanced photographs will assist in achieving better results for future astronomy labs at UNH

Parameterized Complexity of Graph Constraint Logic

Graph constraint logic is a framework introduced by Hearn and Demaine, which provides several problems that are often a convenient starting point for reductions. We study the parameterized complexity of Constraint Graph Satisfiability and both bounded and unbounded versions of Nondeterministic Constraint Logic (NCL) with respect to solution length, treewidth and maximum degree of the underlying constraint graph as parameters. As a main result we show that restricted NCL remains PSPACE-complete on graphs of bounded bandwidth, strengthening Hearn and Demaine's framework. This allows us to improve upon existing results obtained by reduction from NCL. We show that reconfiguration versions of several classical graph problems (including independent set, feedback vertex set and dominating set) are PSPACE-complete on planar graphs of bounded bandwidth and that Rush Hour, generalized to $k\times n$ boards, is PSPACE-complete even when $k$ is at most a constant

Open subgroups of the automorphism group of a right-angled building

We study the group of type-preserving automorphisms of a right-angled building, in particular when the building is locally finite. Our aim is to characterize the proper open subgroups as the finite index closed subgroups of the stabilizers of proper residues. One of the main tools is the new notion of firm elements in a right-angled Coxeter group, which are those elements for which the final letter in each reduced representation is the same. We also introduce the related notions of firmness for arbitrary elements of such a Coxeter group and $n$-flexibility of chambers in a right-angled building. These notions and their properties are used to determine the set of chambers fixed by the fixator of a ball. Our main result is obtained by combining these facts with ideas by Pierre-Emmanuel Caprace and Timoth\'ee Marquis in the context of Kac-Moody groups over finite fields, where we had to replace the notion of root groups by a new notion of root wing groups.Comment: 29 page

The Senior Communicator of the Future – Competencies and Training Needs

Sanchez (2005) proposed the future leading communicator as: “the true professional [who] will be an adroit strategist, a creative technician and a skilled facilitator – a friend of technology and an exponent of life-long learning. The future is a global voyage into the art and science of communication, where the successful communicator will be like the men and women of the Renaissance, pulling it all together, but in the high tech environment of the 21st century.” (pp.10-11) Since the 1980s, starting from Broom and Dozier’s seminal studies on the nature of public relations employment and professionalism, there has been discussion of the career paths, competencies and training needs of public relations and corporate communication professionals. More recently, the Arthur W. Page Society (2007) has scoped the role of the Chief Communication Officer’s role in the Authentic Enterprise which placed the communicator at C-Level (Executive Board) or close to it (the marzipan layer) of the corporation. The research to be reported in this paper analyses the responses of leading European and international senior-level communicators as to the knowledge, skills, relationships, 360-degree vision, and managerial abilities that senior communications professionals will need in five years’ time, and what it takes to prepare the next generation of leaders in globally integrated organizations. The paper will also reflect on recent academic and practice literature about the nature of these competencies and discusses the potential methods and routes of their delivery. It will also consider the current operating situation, the challenges facing senior corporate communicators and their future needs. The outcomes will include recommendations for consideration by educators and employers, especially those operating in cross-cultural environments

On the "initial" Angular Momentum of Galaxies

Spherical density profiles and specific angular momentum profiles of Dark Matter halos found in cosmological N-body simulations have been measured extensively. The distribution of the total angular momentum of dark matter halos is also used routinely in semi-analytic modeling of the formation of disk galaxies. However, it is unclear whether the initial (i.e. at the time the halo is assembled) angular momentum distributions of baryons is related to the dark matter at all. Theoretical models for ellipticities in weak lensing studies often rely on an assumed correlation of the angular momentum vectors of dark matter and gas in galaxies. Both of these assumptions are shown to be in reasonable agreement with high resolution cosmological smoothed particle hydrodynamical simulations that follow the dark matter as long as only adiabatic gas physics are included. However, we argue that in more realistic models of galaxy formation one expects pressure forces to play a significant role at turn--around. Consequently the torquing force on DM and baryons will be uncorrelated and their respective angular momenta are not expected to align. An SPH simulation with ad-hoc feedback is presented that illustrates these effects. Massive low redshift elliptical galaxies may be a notable exception where "light may trace mass".Comment: 4 latex pages (uses sprocl.sty), 1 eps figure. To appear in the proceedings of "The Shapes of Galaxies and Their Halos", Yale, May 200