Stellar Orbits and the Interstellar Gas Temperature in Elliptical Galaxies

We draw attention to the close relationship between the anisotropy parameter beta(r) for stellar orbits in elliptical galaxies and the temperature profile T(r) of the hot interstellar gas. For nearly spherical galaxies the gas density can be accurately determined from X-ray observations and the stellar luminosity density can be accurately found from the optical surface brightness. The Jeans equation and hydrostatic equilibrium establish a connection between beta(r) and T(r) that must be consistent with the observed stellar velocity dispersion. Purely optical observations of the bright elliptical galaxy NGC 4472 indicate beta(r) < 0.35 within the effective radius. However, the X-ray gas temperature profile T(r) for NGC 4472 requires significantly larger anisotropy, beta = 0.6 - 0.7, about twice the optical value. This strong preference for radial stellar orbits must be understood in terms of the formation history of massive elliptical galaxies. Conversely, if the smaller, optically determined anisotropy is indeed correct, we are led to the important conclusion that the temperature profile T(r) of the hot interstellar gas in NGC 4472 must differ from that indicated by X-ray observations, or that the hot gas is not in hydrostatic equilibrium.Comment: 6 pages (emulateapj5) with 4 figures; accepted by The Astrophysical Journa

Educational Operations Four Days a Week

Four day work weeks have been employed by industry, state agencies, and recently by higher education. The generally perceived benefit of the four day work week is reduced energy costs. These costs savings include more efficient building operations and less energy consumption driving to a facility. The generally perceived negative impact of four day operations, particularly of state agencies, is a decreased level of service. How much energy would be saved and could the level of service be maintained in a higher educational environment by switching from five to four day weeks? This study occurs at a regional university within an Industrial and Engineering Technology department that has exclusive use of a building. The department contains seven degree programs ranging from TAC-ABET programs to non-accredited technical degree programs. During the study period all classes and laboratories were scheduled Monday through Thursday. Staff only worked Monday through Thursday. Faculty but not students could gain access to the building on Fridays. The objective of this paper is to study the costs, benefits, and educational impacts of changing the five day academic and building availability week to four days a week. The paper will present the costs savings and the results of a survey of stakeholders collected during one academic quarter. The results of the energy costs are presented in tabular form and the results of the survey are presented in graphical form. The data and conclusions are expected to help decision makers make informed decisions when contemplating an alternative work schedule for higher education

What Does Dynamic Optimality Mean in External Memory?

A data structure A is said to be dynamically optimal over a class of data structures ? if A is constant-competitive with every data structure C ? ?. Much of the research on binary search trees in the past forty years has focused on studying dynamic optimality over the class of binary search trees that are modified via rotations (and indeed, the question of whether splay trees are dynamically optimal has gained notoriety as the so-called dynamic-optimality conjecture). Recently, researchers have extended this to consider dynamic optimality over certain classes of external-memory search trees. In particular, Demaine, Iacono, Koumoutsos, and Langerman propose a class of external-memory trees that support a notion of tree rotations, and then give an elegant data structure, called the Belga B-tree, that is within an O(log log N)-factor of being dynamically optimal over this class. In this paper, we revisit the question of how dynamic optimality should be defined in external memory. A defining characteristic of external-memory data structures is that there is a stark asymmetry between queries and inserts/updates/deletes: by making the former slightly asymptotically slower, one can make the latter significantly asymptotically faster (even allowing for operations with sub-constant amortized I/Os). This asymmetry makes it so that rotation-based search trees are not optimal (or even close to optimal) in insert/update/delete-heavy external-memory workloads. To study dynamic optimality for such workloads, one must consider a different class of data structures. The natural class of data structures to consider are what we call buffered-propagation trees. Such trees can adapt dynamically to the locality properties of an input sequence in order to optimize the interactions between different inserts/updates/deletes and queries. We also present a new form of beyond-worst-case analysis that allows for us to formally study a continuum between static and dynamic optimality. Finally, we give a novel data structure, called the J?llo Tree, that is statically optimal and that achieves dynamic optimality for a large natural class of inputs defined by our beyond-worst-case analysis

Advanced Estimation of Coastal Storm Surge: Application of Swan+Adcirc in Northeast Florida/Georgia Storm Surge

Source: ICHE Conference Archive - https://mdi-de.baw.de/icheArchiv

Life and efficiency of incandescent lamps

Citation: Bender, Louis Blaine and Davis, William DeOzro. Life and efficiency of incandescent lamps. Senior thesis, Kansas State Agricultural College, 1904.Morse Department of Special CollectionsIntroduction: The intelligent selection and proper use of incandescent lamps largely determine the volume and growth of the electric lighting industry. Nothing produces such radical improvement in the lighting service as, first, the exclusive use of the best lamps and, second, the frequent and regular renewal of dim lamps. These principles are the precepts and practice of the leading central stations of the country, and should be law for every electric lighting company. Central stations are in the business of making and selling light. They may sell by the Watt hour or by contract, but, regardless of the way it is measured, the customer is in reality buying and using light. Since the lamp transforms the electrical energy of the generators into light, the best lamp is an absolute necessity to obtain the best light. It is, then, almost a self-evident truth that the exclusive use of the best lamps is the only means of obtaining the best results

Automated Mesh Development Tools for Central Florida Storm Surge Study

Source: ICHE Conference Archive - https://mdi-de.baw.de/icheArchiv

Letter, to Louis J. Krueger, Gerald Tomanek, Warren Corman and Edmund G. Ahrens, from Roger D. Bender and William B. Livingston, March 28, 1977

Letter from Architects 3+2 stating their qualification to perform work on the new proposed building.https://scholars.fhsu.edu/rarick/1020/thumbnail.jp