7,074 research outputs found
Security warning system monitors up to fifteen remote areas simultaneously
Security warning system consisting of 15 television cameras is capable of monitoring several remote or unoccupied areas simultaneously. The system uses a commutator and decommutator, allowing time-multiplexed video transmission. This security system could be used in industrial and retail establishments
Spacelab 4: Primate experiment support hardware
A squirrel monkey feeder and automatic urine collection system were designed to fly on the Spacelab 4 Shuttle Mission presently scheduled for January 1986. Prototypes of the feeder and urine collection systems were fabricated and extensively tested on squirrel monkeys at the National Aeronautics and Space Administration's (NASA) Ames Research Center (ARC). The feeder design minimizes impact on the monkey's limited space in the cage and features improved reliability and biocompatibility over previous systems. The urine collection system is the first flight qualified, automatic urine collection device for squirrel monkeys. Flight systems are currently being fabricated
Supermodel Analysis of the Hard X-Ray Excess in the Coma Cluster
The Supermodel provides an accurate description of the thermal contribution
by the hot intracluster plasma which is crucial for the analysis of the hard
excess. In this paper the thermal emissivity in the Coma cluster is derived
starting from the intracluster gas temperature and density profiles obtained by
the Supermodel analysis of X-ray observables: the XMM-Newton temperature
profile and the Rosat brightness distribution. The Supermodel analysis of the
BeppoSAX/PDS hard X-ray spectrum confirms our previous results, namely an
excess at the c.l. of ~4.8sigma and a nonthermal flux of 1.30+-0.40x 10^-11 erg
cm^-2 s^-1 in the energy range 20-80 keV. A recent joint XMM-Newton/Suzaku
analysis reports an upper limit of ~6x10^-12 erg cm^-2 s^-1 in the energy range
20-80 keV for the nonthermal flux with an average gas temperature of 8.45+-0.06
keV, and an excess of nonthermal radiation at a confidence level above 4sigma,
without including systematic effects, for an average XMM-Newton temperature of
8.2 keV in the Suzaku/HXD-PIN FOV, in agreement with our earlier PDS analysis.
Here we present a further evidence of the compatibility between the Suzaku and
BeppoSAX spectra, obtained by our Supermodel analysis of the PDS data, when the
smaller size of the HXD-PIN FOV and the two different average temperatures
derived by XMM-Newton and by the joint XMM-Newton/Suzaku analysis are taken
into account. The consistency of the PDS and HXD-PIN spectra reaffirms the
presence of a nonthermal component in the hard X-ray spectrum of the Coma
cluster. The Supermodel analysis of the PDS data reports an excess at c.l.
above 4sigma also for the higher average temperature of 8.45 keV thanks to the
PDS FOV considerably greater than the HXD-PIN FOV.Comment: 18 pages, 7 figures, accepted for publication in Ap
The giant radio halo in Abell 2163
New radio data is presented for the rich cluster Abell 2163. The cluster
radio emission is characterized by the presence of a radio halo, which is one
of the most powerful and extended halos known so far. In the NE peripheral
cluster region, we also detect diffuse elongated emission, which we classify as
a cluster relic. The cluster A2163 is very hot and luminous in X-ray. Its
central region is probably in a highly non relaxed state, suggesting that this
cluster is likely to be a recent merger. The existence of a radio halo in this
cluster confirms that halos are associated with hot massive clusters, and
confirms the connection between radio halos and cluster merger processes. The
comparison between the radio emission of the halo and the cluster X-ray
emission shows a close structural similarity. A power law correlation is found
between the radio and X-ray brightness, with index = 0.64. We also report the
upper limit to the hard X-ray emission, obtained from a BeppoSAX observation.
We discuss the implications of our results.Comment: 7 pages, 8 figures (5 in ps and 3 in gif), Accepted for publication
in Astron. Astrop
Transforming Service Learning: An Argument for the Radical Inclusion of Young People
While much has been written delineating the reasons for supporting service learning, rarely have students\u27 views been included. As a result of creating collective dialogues with young people, this article presents service learning from their perspective. Further, the methodology by which young people could be heard is put forth as a tool for bringing service learning to a new level
Distance and reddening of the Local Group dwarf irregular galaxy NGC 6822
On the basis of a new photometric analysis of the Local Group dwarf irregular
galaxy NCG 6822 based on observations obtained with the Advanced Camera for
Surveys onboard the Hubble Space Telescope, we have obtained a new estimate of
the extinction of two fields located in the southeast region of the galaxy.
Because of significant differences in the distance estimates to NGC 6822
available in literature, we decided to provide an independent determination of
the distance to this galaxy based on an updated and self-consistent theoretical
calibration of the tip of the red giant branch brightness. As a result we newly
determined the distance to NGC 6822 to be equal to , and compared our measurement with the most recent determinations of this
distance.Comment: 5 pages, 5 figures, Astronomy & Astrophysics (Research Note), in
press (proof correction included
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