1,521 research outputs found
Grid-enabling FIRST: Speeding up simulation applications using WinGrid
The vision of grid computing is to make computational power, storage capacity, data and applications available to users as readily as electricity and other utilities. Grid infrastructures and applications have traditionally been geared towards dedicated, centralized, high performance clusters running on UNIX flavour operating systems (commonly referred to as cluster-based grid computing). This can be contrasted with desktop-based grid computing which refers to the aggregation of non-dedicated, de-centralized, commodity PCs connected through a network and running (mostly) the Microsoft Windowstrade operating system. Large scale adoption of such Windowstrade-based grid infrastructure may be facilitated via grid-enabling existing Windows applications. This paper presents the WinGridtrade approach to grid enabling existing Windowstrade based commercial-off-the-shelf (COTS) simulation packages (CSPs). Through the use of a case study developed in conjunction with Ford Motor Company, the paper demonstrates how experimentation with the CSP Witnesstrade and FIRST can achieve a linear speedup when WinGridtrade is used to harness idle PC computing resources. This, combined with the lessons learned from the case study, has encouraged us to develop the Web service extensions to WinGridtrade. It is hoped that this would facilitate wider acceptance of WinGridtrade among enterprises having stringent security policies in place
NASA/FAA helicopter simulator workshop
A workshop was convened by the FAA and NASA for the purpose of providing a forum at which leading designers, manufacturers, and users of helicopter simulators could initiate and participate in a development process that would facilitate the formulation of qualification standards by the regulatory agency. Formal papers were presented, special topics were discussed in breakout sessions, and a draft FAA advisory circular defining specifications for helicopter simulators was presented and discussed. A working group of volunteers was formed to work with the National Simulator Program Office to develop a final version of the circular. The workshop attracted 90 individuals from a constituency of simulator manufacturers, training organizations, the military, civil regulators, research scientists, and five foreign countries
Part 1: Executive summary
A workshop was convened by the FAA and NASA for the purpose of providing a forum at which leading designers, manufacturers, and users of helicopter simulators could initiate and participate in a development process that would facilitate the formulation of qualification standards by the regulatory agency. Formal papers were presented, special topics were discussed in breakout sessions, and a draft FAA advisory circular defining specifications for helicopter simulators was presented and discussed. A working group of volunteers was formed to work with the National Simulator Program Office to develop a final version of the circular. The workshop attracted 90 individuals from a constituency of simulator manufacturers, training organizations, the military, civil regulators, research scientists, and five foreign countries. A great amount of information was generated and recorded verbatim. This information is presented herein within the limits of accuracy inherent in recording, transcribing, and editing spoken technical material
Conservation Agriculture as Practised in Ghana
This case study presents the status of conservation agriculture in Ghana. It is one in a series of eight case studies about conservation agriculture in Africa, which were developed within the framework of a collaboration between CIRAD (French Agricultural Research Centre for International Development), FAO (Food and Agriculture Organization of the United Nations), RELMA-in-ICRAF (Regional Land Management Unit of the World Agroforestry Centre) and ACT (African Conservation Tillage Network)
A High Throughput Assay to Identify Small Molecule Modulators of Prostatic Acid Phosphatase
Prostatic acid phosphatase (PAP) is expressed in nociceptive neurons and functions as an ectonucleotidase. Injection of the secretory isoform of PAP has potent antinociceptive effects in mouse models of chronic pain. These data suggested that a small molecule activator of PAP may have utility as a novel therapeutic for chronic pain, while inhibitors could be used to acutely inhibit PAP in vitro and in vivo. To identify small molecule modulators of PAP activity, we validated a high throughput, fluorescence-based biochemical assay and then used this assay to screen a compound library. We decreased the frequency of false positive activators by subtracting compound fluorescence from the final assay fluorescence. This approach significantly reduced the number of false positive activators found in the screen. While no activators were confirmed, seven novel inhibitors of PAP were identified. Our results suggest this high throughput assay could be used to identify small molecule modulators of PAP activity
Sizes and Shapes of Young Star Cluster Light Profiles in M83
We measure the radii and two-dimensional light profiles of a large sample of
young, massive star clusters in M83 using archival HST/WFC3 imaging of seven
adjacent fields. We use GALFIT to fit the two-dimensional light profiles of the
clusters, from which we find effective (half-light) radii, core radii, and
slopes of the power-law (EFF) profile (). We find lognormal distributions
of effective radius and core radius, with medians of 2.5 pc and
1.3 pc, respectively. Our results provide strong evidence for a
characteristic size of young, massive clusters. The average effective radius
and core radius increase somewhat with cluster age. Little to no change in
effective radius is observed with increasing galactocentric distance, except
perhaps for clusters younger than 100 Myr. We find a shallow correlation
between effective radius and mass for the full cluster sample, but a stronger
correlation is present for clusters 200-300 Myr in age. Finally, the majority
of the clusters are best fit by an EFF model with index . There is
no strong evidence for change in with cluster age, mass, or
galactocentric distance. Our results suggest that clusters emerge from early
evolution with similar radii and are not strongly affected by the tidal field
of M83. Mass loss due to stellar evolution and/or GMC interactions appear to
dominate cluster expansion in the age range we study.Comment: 34 pages, 11 figures, 3 tables, accepted by MNRAS. Machine-readable
table attached (full version of Table 3). To obtain, download the source file
from the "Other formats" link abov
Structural Parameters of the M87 Globular Clusters
We derive structural parameters for ~2000 globular clusters in the giant
Virgo elliptical M87 using extremely deep Hubble Space Telescope images in
F606W (V) and F814W (I) taken with the ACS/WFC. The cluster scale sizes
(half-light radii r_h) and ellipticities are determined from PSF-convolved
King-model profile fitting. We find that the r_h distribution closely resembles
the inner Milky Way clusters, peaking at r_h~2.5 pc and with virtually no
clusters more compact than r_h ~ 1 pc. The metal-poor clusters have on average
an r_h 24% larger than the metal-rich ones. The cluster scale size shows a
gradual and noticeable increase with galactocentric distance. Clusters are very
slightly larger in the bluer waveband V a possible hint that we may be
beginning to see the effects of mass segregation within the clusters. We also
derived a color magnitude diagram for the M87 globular cluster system which
show a striking bimodal distribution.Comment: ApJ accepte
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