High energy X-ray results from HEAO-1: X-ray pulsars, and the all sky survey

Results of the sky survey performed with the high energy X-ray detectors of the A-4 experiment onboard the HEAO 1 spacecraft are presented. The data presented cover the energy range from 13 to 80 keV. Strong sources are identified by visual inspection and azimuthal superpositions are performed in order to find weak sources. Time variability is also examined. Results of studies of X-ray pulsars are given including a brief description of an X-ray pulsar in terms of current theory

Management of large-scale technology

Two major themes are addressed in this assessment of the management of large-scale NASA programs: (1) how a high technology agency was a decade marked by a rapid expansion of funds and manpower in the first half and almost as rapid contraction in the second; and (2) how NASA combined central planning and control with decentralized project execution

The NASA/Baltimore Applications Project (BAP). Computer aided dispatch and communications system for the Baltimore Fire Department: A case study of urban technology application

An engineer and a computer expert from Goddard Space Flight Center were assigned to provide technical assistance in the design and installation of a computer assisted system for dispatching and communicating with fire department personnel and equipment in Baltimore City. Primary contributions were in decision making and management processes. The project is analyzed from four perspectives: (1) fire service; (2) technology transfer; (3) public administration; and (5) innovation. The city benefitted substantially from the approach and competence of the NASA personnel. Given the proper conditions, there are distinct advantages in having a nearby Federal laboratory provide assistance to a city on a continuing basis, as is done in the Baltimore Applications Project

Comment: On Random Scan Gibbs Samplers

Comment on ``On Random Scan Gibbs Samplers'' [arXiv:0808.3852]Comment: Published in at http://dx.doi.org/10.1214/08-STS252B the Statistical Science (http://www.imstat.org/sts/) by the Institute of Mathematical Statistics (http://www.imstat.org

Properties of Cooperatively Induced Phases in Sensing Models

A large number of eukaryotic cells are able to directly detect external chemical gradients with great accuracy and the ultimate limit to their sensitivity has been a topic of debate for many years. Previous work has been done to understand many aspects of this process but little attention has been paid to the possibility of emergent sensing states. Here we examine how cooperation between sensors existing in a two dimensional network, as they do on the cell's surface, can both enhance and fundamentally alter the response of the cell to a spatially varying signal. We show that weakly interacting sensors linearly amplify the sensors response to an external gradient while a network of strongly interacting sensors form a collective non-linear response with two separate domains of active and inactive sensors forming what have called a "1/2-state" . In our analysis we examine the cell's ability to sense the direction of a signal and pay special attention to the substantially different behavior realized in the strongly interacting regime.Comment: 8 pages, 5 figure