Abstra t Let the edges of a graph G be oloured so that no olour is used more than k times. We refer to this as a k-bounded olouring. We say that a subset of the edges of G is multi oloured if ea h edge is of a di erent olour. We say that the olouring is H-good, if a multi oloured Hamilton y le exists i.e., one with a multi oloured edgeset. Let ARk = fG : every k-bounded olouring of G is H-goodg...

Yi-Chih Chien and Glen E. Collier (1997) Biochemical comparison of arginine kinase allozymes in Drosophila melanogaster. Zoological Studies 36(4): 277-287. ARKs is a rare arginine kinase allozyme found in natural populations of Drosophila melanogaster. To test whether the rarity of this allozyme could be due to its biochemical impairment relative to the common allozyme, biochemical properties s...

We present spatial, temporal and spectral analyses of ROSAT Position Sensitive Pro-Ark 564 is a powerful narrow-line Seyfert 1 with strong Fe ii emission. Several similar narrow-line Seyfert 1 galaxies have recently been found to have remarkably steep soft X-ray continua as well as rapid X-ray variability. We nd that Ark 564 also has a very steep ((> 3) 0.1{2.5 keV spectrum and varies by 20 per...

The Hedgehog (Hh) pathway was first defined by its role in segment polarity in the Drosophila melanogaster embryonic epidermis and has since been linked to many aspects of vertebrate development and disease. In humans, mutation of the Patched1 (PTCH1) gene, which encodes an inhibitor of Hh signaling, leads to tumors of the skin and pediatric brain. Despite the high level of conservation between...

Many groups of extinct and extant organisms have aggregated to form reefs for over 3.5 billion yr (Ga). Most of these communities, however, grew under ecological and environmental controls profoundly different from those that govern modern coral reefs. Not only has the global distribution of reefs varied considerably through geological time—determined largely by sea level, and latitudinal tempe...