The communications technology satellite and the associated ground terminals for experiments

General spacecraft operational characteristics of the Communications Technology Satellite are discussed with particular emphasis on communication system parameters. Associated used ground terminals are reviewed. Wideband communications are also discussed

The effect of expository writing as a pre-reading activity on comprehension of expository text

The purpose of this study was to examine the effect of a pre-reading expository writing task on comprehension of expository text. It was undertaken in order to ascertain the usefulness of writing as a pre-reading activity in the development of schema theoretic reading teaching strategies. The theoretical position of the study was that writing before reading would activate prior knowledge in the form of content and structure in the working memory of the reader and thereby enhance reading comprehension. The sample, comprised selected from a small, of 51 year 6/7 students, school in the outskirts of was the metropolitan area. These students were systematically allocated to one of three equivalent groups on the basis of standardised reading comprehension test results. The experiment followed a three group, post-test only design, with two control groups and one experimental. The experimental group participated in a 20 minute writing activity on the topic of animal conservation. One control group participated in a writing activity on the topic of television”, while the other control participated iq maths activities, i.e., they did not write, At the conclusion of this 20 minute session, all groups read a text about animal conservation then completed a probe question comprehension test containing explicit and inferential questions relating to the text. The results of the short answer test were quantified in two sections, i.e., responses to explicit questions and responses to inferential questions, and the results were analysed by one way analysis of variance

COMPETITIVE GRANTS AND THE FUNDING OF AGRICULTURAL RESEARCH IN THE U.S.

To increase the efficiency of the public agricultural R&D system, expanded use of competitive grants to fund state institutions has been advocated. This paper characterizes different funding instruments and empirically assesses the effects of changes in mechanism use. Factors associated with greater levels of competitive grants are modeled.Research and Development/Tech Change/Emerging Technologies,

Electron Spin Precession at CEBAF

The nuclear physics experiments at the Thomas Jefferson National Accelerator Facility often require longitudinally polarized electrons to be simultaneously delivered to three experimental halls. The degree of longitudinal polarization to each hall varies as function of the accelerator settings, making it challenging in certain situations to deliver a high degree of longitudinal polarization to all the halls simultaneously. Normally, the degree of longitudinal polarization the halls receive is optimized by changing the initial spin direction at the beginning of the machine with a Wien filter. Herein, it is shown that it is possible to further improve the degree of longitudinal polarization for multiple experimental halls by redistributing the energy gain of the CEBAF linacs while keeping the total energy gain fixed.Comment: 4 pages, 3 figures, to appear in the proceedings of the 18th International Symposium on Spin Physics (SPIN2008

Control System for the LEDA 6.7-MeV Proton Beam Halo Experiment

Measurement of high-power proton beam-halo formation is the ongoing scientific experiment for the Low Energy Demonstration Accelerator (LEDA) facility. To attain this measurement goal, a 52-magnet beam line containing several types of beam diagnostic instrumentation is being installed. The Experimental Physics and Industrial Control System (EPICS) and commercial software applications are presently being integrated to provide a real-time, synchronous data acquisition and control system. This system is comprised of magnet control, vacuum control, motor control, data acquisition, and data analysis. Unique requirements led to the development and integration of customized software and hardware. EPICS real-time databases, Interactive Data Language (IDL) programs, LabVIEW Virtual Instruments (VI), and State Notation Language (SNL) sequences are hosted on VXI, PC, and UNIX-based platforms which interact using the EPICS Channel Access (CA) communication protocol. Acquisition and control hardware technology ranges from DSP-based diagnostic instrumentation to the PLC-controlled vacuum system. This paper describes the control system hardware and software design, and implementation.Comment: LINAC2000 Conference, 4 pg

Electronic Structures of Nitridomanganese(V) Complexes

The single-crystal polarized absorption and circular dichroism spectra of the nitridomanganese(V) complexes (salen)Mn⋮N (1), (1S,2S-(−)-saldpen)Mn⋮N (2), and (1R,2R-(+)-saldpen)Mn⋮N (3) have been measured [salen = N,N‘-ethylenebis(salicylideneaminato) dianion, 1S,2S-(−)-saldpen = N,N‘-(1S,2S-(−)-diphenyl)ethylenebis(salicylideneaminato) dianion, and 1R,2R-(+)-saldpen = N,N‘-(1R,2R-(+)-diphenyl)ethylenebis(salicylideneaminato) dianion]. As revealed by X-ray crystal structure analyses, these molecules have a distorted square-pyramidal geometry with a short Mn⋮N bond distance (1.52(3) Å for 2). The Cs compounds have a low-spin^ 1A‘[a‘(x^2 − y^2)]^2 ground state. The lowest absorption system (∼600 nm) consists of two components that are separated by approximately 4000 cm^(-1); these are assigned to ^1A‘ → ^1A‘[a‘(x^2 − y^2)a‘(yz)] (14 900 cm^(-1)) and ^1A‘ → ^1A‘‘[a‘(x^2 − y^2)a‘‘(xz)] (18 900 cm^(-1)) transitions

Calculating the virtual cohomological dimension of the automorphism group of a RAAG

We describe an algorithm to find the virtual cohomological dimension of the automorphism group of a right-angled Artin group. The algorithm works in the relative setting; in particular it also applies to untwisted automorphism groups and basis-conjugating automorphism groups. The main new tool is the construction of free abelian subgroups of certain Fouxe-Rabinovitch groups of rank equal to their virtual cohomological dimension, generalizing a result of Meucci in the setting of free groups.Comment: 15 pages, 2 figures. Revised background on RORGs, small changes elsewhere. Accepted to appear in Bulletin of the LM