5,936 research outputs found
Space shuttle engineering and operations support. Avionics system engineering
The shuttle avionics integration laboratory (SAIL) requirements for supporting the Spacelab/orbiter avionics verification process are defined. The principal topics are a Spacelab avionics hardware assessment, test operations center/electronic systems test laboratory (TOC/ESL) data processing requirements definition, SAIL (Building 16) payload accommodations study, and projected funding and test scheduling. Because of the complex nature of the Spacelab/orbiter computer systems, the PCM data link, and the high rate digital data system hardware/software relationships, early avionics interface verification is required. The SAIL is a prime candidate test location to accomplish this early avionics verification
Particles in RSOS paths
We introduce a new representation of the paths of the Forrester-Baxter RSOS
models which represents the states of the irreducible modules of the minimal
models M(p',p). This representation is obtained by transforming the RSOS paths,
for the cases p> 2p'-2, to new paths for which horizontal edges are allowed at
certain heights. These new paths are much simpler in that their weight is
nothing but the sum of the position of the peaks. This description paves the
way for the interpretation of the RSOS paths in terms of fermi-type charged
particles out of which the fermionic characters could be obtained
constructively. The derivation of the fermionic character for p'=2 and p=kp'+/-
1 is outlined. Finally, the particles of the RSOS paths are put in relation
with the kinks and the breathers of the restricted sine-Gordon model.Comment: 15 pages, few typos corrected, version publishe
The Orbital Light Curve of Aquila X-1
We obtained R- and I-band CCD photometry of the soft X-ray transient/neutron-
star binary Aql X-1 in 1998 June while it was at quiescence. We find that its
light curve is dominated by ellipsoidal variations, although the ellipsoidal
variations are severely distorted and have unequal maxima. After we correct for
the contaminating flux from a field star located only 0.46" away, the
peak-to-peak amplitude of the modulation is ~0.25 mag in the R band, which
requires the orbital inclination to be greater than 36 degrees. The orbital
period we measure is consistent with the 18.95 h period measured by Chevalier &
Ilovaisky (1998). During its outbursts the light curve of Aql X-1 becomes
single humped. The outburst light curve observed by Garcia et al. (1999) agrees
in phase with our quiescent light curve. We show that the single humped
variation is caused by a ``reflection effect,'' that is, by heating of the side
of the secondary star facing towards the neutron star.Comment: 18 manuscript pages, 7 figures; accepted by A
An Economic analysis of the potential for precision farming in UK cereal production
The results from alternative spatial nitrogen application studies are analysed in economic terms and compared to the costs of precision farming hardware, software and other services for cereal crops in the UK. At current prices, the benefits of variable rate application of nitrogen exceed the returns from a uniform application by an average of £22 ha−1 The cost of the precision farming systems range from £5 to £18 ha−1 depending upon the system chosen for an area of 250 ha. The benefits outweigh the associated costs for cereal farms in excess of 80 ha for the lowest price system to 200–300 ha for the more sophisticated systems. The scale of benefits obtained depends upon the magnitude of the response to the treatment and the proportion of the field that will respond. To be cost effective, a farmed area of 250 ha of cereals, where 30% of the area will respond to variable treatment, requires an increase in crop yield in the responsive areas of between 0·25 and 1.00 t ha−1 (at £65 t−1) for the basic and most expensive precision farming systems, respectively
Using Geographic Information Systems to investigate variations in accessibility to ‘extended hours’ primary healthcare provision
There are ongoing policy concerns surrounding the difficulty in obtaining timely appointments to primary healthcare services and the potential impact on, for example, attendance at accident and emergency services and potential health outcomes. Using the case study of potential access to primary healthcare services in Wales, Geographic Information System (GIS)‐based tools that permit a consideration of population‐to‐provider ratios over space are used to examine variations in geographical accessibility to general practitioner (GP) surgeries offering appointment times outside of ‘core’ operating hours. Correlation analysis is used to explore the association of accessibility scores with potential demand for such services using UK Population Census data. Unlike the situation in England, there is a tendency for accessibility to those surgeries offering ‘extended’ hours of appointment times to be better for more deprived census areas in Wales. However, accessibility to surgeries offering appointments in the evening was associated with lower levels of working age population classed as ‘economically active’; that is, those who could be targeted beneficiaries of policies geared towards ‘extended’ appointment hours provision. Such models have the potential to identify spatial mismatches of different facets of primary healthcare, such as ‘extended’ hours provision available at GP surgeries, and are worthy of further investigation, especially in relation to policies targeted at particular demographic groups
Ariel - Volume 5 Number 5
Editors
Mark Dembert
J. D. Kanofsky
Entertainment
Robert Breckenridge
Joe Conti
Gary Kaskey
Photographer
Scot Kastner
Overseas Editor
Mike Sinason
Circulation
Jay Amsterdam
Humorist
Jim McCann
Staff
Ken Jaffe
Bob Sklaroff
Janet Welsh
Dave Jacoby
Phil Nimoityn
Frank Chervane
On the fundamental group of the complement of a complex hyperplane arrangement
We construct two combinatorially equivalent line arrangements in the complex
projective plane such that the fundamental groups of their complements are not
isomorphic. The proof uses a new invariant of the fundamental group of the
complement to a line arrangement of a given combinatorial type with respect to
isomorphisms inducing the canonical isomorphism of the first homology groups.Comment: 12 pages, Latex2e with AMSLaTeX 1.2, no figures; this last version is
almost the same as published in Functional Analysis and its Applications 45:2
(2011), 137-14
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