6,096 research outputs found
A New Experiment to Study Hyperon CP Violation and the Charmonium System
Fermilab operates the world's most intense antiproton source, now exclusively
dedicated to serving the needs of the Tevatron Collider. The anticipated 2009
shutdown of the Tevatron presents the opportunity for a world-leading low- and
medium-energy antiproton program. We summarize the status of the Fermilab
antiproton facility and review physics topics for which a future experiment
could make the world's best measurements.Comment: 16 pages, 3 figures, to appear in Proceedings of CTP symposium on
Supersymmetry at LHC: Theoretical and Experimental Perspectives, The British
University in Egypt, Cairo, Egypt, 11-14 March 200
Supernova Environments in Hubble Space Telescope Images
The locations of supernovae in the local stellar and gaseous environment in galaxies contain important clues to their progenitor stars. Access to this information, however, has been hampered by the limited resolution achieved by ground-based observations. High spatial resolution Hubble Space Telescope (HST) images of galaxy fields in which supernovae had been observed can improve the situation considerably. We have examined the immediate environments of a few dozen supernovae using archival post-refurbishment HST images. Although our analysis is limited due to signal-to-noise ratio and filter bandpass considerations, the images allow us for the first time to resolve individual stars in, and to derive detailed color-magnitude diagrams for, several environments. We are able to place more rigorous constraints on the masses of these supernovae. A search was made for late-time emission from supernovae in the archival images, and for the progenitor stars in presupernova images of the host galaxies. In particular, we highlight the results for the Type II SN 1979C in M100. In addition, we have identified the progenitor of the Type IIn SN 1997bs in NGC 3627. We also add to the statistical inferences that can be made from studying the association of SNe with recent star-forming regions
Multilevel semantic analysis and problem-solving in the flight domain
A computer based cockpit system which is capable of assisting the pilot in such important tasks as monitoring, diagnosis, and trend analysis was developed. The system is properly organized and is endowed with a knowledge base so that it enhances the pilot's control over the aircraft while simultaneously reducing his workload
Lensed Quasar Hosts
Gravitational lensing assists in the detection of quasar hosts by amplifying
and distorting the host light away from the unresolved quasar core images. We
present the results of HST observations of 30 quasar hosts at redshifts 1 < z <
4.5. The hosts are small in size (r_e <~ 6 kpc), and span a range of
morphologies consistent with early-types (though smaller in mass) to
disky/late-type. The ratio of the black hole mass (MBH, from the virial
technique) to the bulge mass (M_bulge, from the stellar luminosity) at 1<z<1.7
is broadly consistent with the local value; while MBH/M_bulge at z>1.7 is a
factor of 3--6 higher than the local value. But, depending on the stellar
content the ratio may decline at z>4 (if E/S0-like), flatten off to 6--10 times
the local value (if Sbc-like), or continue to rise (if Im-like). We infer that
galaxy bulge masses must have grown by a factor of 3--6 over the redshift range
3>z>1, and then changed little since z~1. This suggests that the peak epoch of
galaxy formation for massive galaxies is above z~1. We also estimate the duty
cycle of luminous AGNs at z>1 to be ~1%, or 10^7 yrs, with sizable scatter.Comment: 8 pages, 6 figures, review article with C. Impey at the conference on
"QSO Host Galaxies: Evolution and Environment", Aug. 29-Sep. 2, 2005, Lorentz
Center, Leiden, The Netherland
Current-induced spin-wave excitations in a single ferromagnetic layer
A new current induced spin-torque transfer effect has been observed in a
single ferromagnetic layer without resorting to multilayers. At a specific
current density of one polarity injected from a point contact, abrupt
resistance changes due to current-induced spin wave excitations have been
observed. The critical current at the onset of spin-wave excitations depends
linearly on the external field applied perpendicular to the layer. The observed
effect is due to current-driven heterogeneity in an otherwise uniform
ferromagnetic layer.Comment: 12 pages, 4 figure
Insights on quorum-quenching properties of Lysinibacillus fusiformis strain RB21, a Malaysian municipal solid-waste landfill soil isolate, via complete genome sequence analysis
YesLysinibacillus fusiformis strain RB21 is a quorum-quenching bacterium that is able to degrade quorum-sensing signaling molecules. Here, we present the first complete genome sequence of L. fusiformis strain RB21. The finished genome is 4.8 Mbp in size, and the quorum-quenching gene was identified.University of Malaya for High Impact Research (UM-MOHE HIR) grant UM C/625/1/HIR/MOHE/CHAN/01, no. A000001-50001 and grant UM C/625/1/HIR/MOHE/CHAN/14/1, H-50001-A00002
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