Abstract. The current system of stellar magnitudes first introduced by Hipparchus was strictly defined by Norman Robert Pogson in 1856. He based his system on Ptolemy’s star catalogue ‘Almagest’, recorded in about 137 A.D., and defined the magnitude-intensity relationship on a logarithmic scale. Stellar magnitudes observed with the naked eye recorded in seven old star catalogues were analyzed i...

Near the end of 2001 February, the black-hole candidate (BHC) GRS 1758–258 made an abrupt transition from a standard hard (low) state to a soft state. Unlike Cyg X–1 and other BHCs, whose luminosity increases during this transition, GRS 1758–258 was dimmer after the transition. We present observations with the Proportional Counter Array on the Rossi X-ray Timing Explorer and interpret the pheno...

Near the end of 2001 February, the black-hole candidate (BHC) GRS 1758–258 made an abrupt transition from a standard hard (low) state to a soft state. Unlike Cyg X–1 and other BHCs, whose luminosity increases during this transition, GRS 1758–258 was dimmer after the transition. We present observations with the Proportional Counter Array on the Rossi X-ray Timing Explorer and interpret the pheno...

In a randomized, parallel design, 19 patients with winter depression were treated with either a week of a white 1.5-hr dawn simulation peaking at 250 lux or a week of a red, 1.5-hr dawn signal peaking at 2 lux. The subjects were told that they would receive either a white or red dawn reaching in intensity that would be dimmer than standard bright light treatment. At the end of both the baseline...

Acute lymphoblastic leukemia (ALL) is the most common type of leukemia in childhood and adults. While the survival rate of ALL patients has been improved obviously, nearly one quarter of children with ALL will die (Gaynon, 2005). ALL in adults affects a comparatively young population and has proved to be refractory, with the 5-year survival rate of around 40% (Plasschaert et al., 2004). ALL ori...

We briefly review recent developments in black hole accretion disk theory, placing new emphasis on the vital role played by magnetohydrodynamic (MHD) stresses in transporting angular momentum. The apparent universality of accretion-related outflow phenomena is a strong indicator that vertical transport of angular momentum by large-scale MHD torques is important and may even dominate radial tran...

Abstract The current system of stellar magnitudes first introduced by Hipparchus was strictly defined by Norman Robert Pogson in 1856. He based his system on Ptolemy’s star catalogue ‘Almagest’, recorded in about 137 A.D., and defined the magnitude-intensity relationship on a logarithmic scale. Stellar magnitudes observed with the naked eye recorded in seven old star catalogues were analyzed in...

We have analysed X-ray outbursts from several Galactic black hole (GBH) transients, as seen by the All-Sky Monitor (ASM) on board Rossi X-ray Timing Explorer (RXTE). We have used the best estimates of distance and black hole mass to find their luminosity (scaled to the Eddington limit), which allowed for direct comparison of many sources. We found that the very high and intermediate X-ray spect...

Time: end of the 19th century. Maxwell’s equations have established Faraday’s hunch that light is an electromagnetic wave. However, by early 20th century, experimental evidence mounted pointing towards the fact that light is carried by ‘particles’ that pack a definite momentum and energy. Here is the crux of the problem: consider the double-slit experiment. Monochromatic light of wavelength pas...

The investigation of visual processing mediated solely by chromatic information requires conditions preventing a subject's use of the luminance differences normally accompanying a chromatic change. In Experiment 1, which involved a discriminative reaction time (RT) task, chromatic and white stimuli of the same luminance were presented on a dimmer achromatic background. Subjects were instructed ...