3,278 research outputs found
Some comments on the ''the composition of the Martian surface'' by R. A. Van Tassel and J. W. Salisbury
Feasibility of Martian surface layer composed of silicates coated with limonit
Upper limits on liquid water in the Venus atmosphere
Upper limits on liquid water in Venus atmosphere due to presence of hydrogen chlorid
The Influence of Topography on the Formation of Temporary Bright Patches on Mars
Influence of topography on formation of bright patches on Mar
The atmosphere and surface of Mars A selective review
Martian atmosphere and surface characteristics - astrophysic
The evidence for life on mars- nature and uncertainties
Evidence for life on Mars - nature and uncertaintie
Linking the X-ray timing and spectral properties of the glitching AXP 1RXS J170849-400910
Previous studies of the X-ray flux and spectral properties of 1RXS
J170849-400910 showed hints of a possible correlation with the spin glitches
that occurred in 1999 and 2001. However, due to the sparseness of spectral
measurements and the paucity of detected glitches no firm conclusion could be
drawn. We retrieved and analysed archival XTE pointings of 1RXS J170849-400910
covering the time interval between January 2003 and June 2006 and carried out a
detailed timing analysis by means of phase fitting techniques. We detected two
relatively large glitches Delta nu / nu of 1.2 and 2.1 10^-6 occurred in
January and June 2005. Interestingly, the occurrence times of these glitches
are in agreement with the predictions made in our previous studies. This
finding strongly suggests a connection between the flux, spectral and timing
properties of 1RXS J170849-400910.Comment: Submitted to A&A, 4 pages; results presented at the INT meeting "The
Neutron Star Crust and Surface: Observations and Models" on June 27; referee
comments adde
Lighting as a Circadian Rhythm-Entraining and Alertness-Enhancing Stimulus in the Submarine Environment
The human brain can only accommodate a circadian rhythm that closely follows 24 hours. Thus, for a work schedule to meet the brain’s hard-wired requirement, it must employ a 24 hour-based program. However, the 6 hours on, 12 hours off (6/12) submarine watchstanding schedule creates an 18-hour “day” that Submariners must follow. Clearly, the 6/12 schedule categorically fails to meet the brain’s operational design, and no schedule other than one tuned to the brain’s 24 hour rhythm can optimize performance. Providing Submariners with a 24 hour-based watchstanding schedule—combined with effective circadian entrainment techniques using carefully-timed exposure to light—would allow crewmembers to work at the peak of their daily performance cycle and acquire more restorative sleep. In the submarine environment, where access to natural light is absent, electric lighting can play an important role in actively entraining—and closely maintaining—circadian regulation. Another area that is likely to have particular importance in the submarine environment is the potential effect of light to help restore or maintain alertness
Long term hard X-ray variability of the anomalous X-ray pulsar 1RXS J170849.0-400910 discovered with INTEGRAL
We report on a multi-band high-energy observing campaign aimed at studying
the long term spectral variability of the Anomalous X-ray Pulsar (AXP) 1RXS
J170849.0-400910, one of the magnetar candidates. We observed 1RXS
J170849.0-400910 in Fall 2006 and Spring 2007 simultaneously with Swift/XRT, in
the 0.1-10 keV energy range, and with INTEGRAL/IBIS, in the 20-200 keV energy
range. Furthermore, we also reanalyzed, using the latest calibration and
software, all the publicly available INTEGRAL data since 2002, and the soft
X-ray data starting from 1999 taken using BeppoSAX, Chandra, XMM, and
Swift/XRT, in order to study the soft and hard X-ray spectral variability of
1RXS J170849.0-400910. We find a long-term variability of the hard X-ray flux,
extending the hardness-intensity correlation proposed for this source over 2
orders of magnitude in energy.Comment: 5 pages, 2 figures, accepted for publication in Astronomy &
Astrophysics main journa
- …