This note describes a combinatorial optimization problem arising in the Sloan Digital Sky Survey and an effective heuristic for the problem that has been implemented and will be used in the Survey. The heuristic is based on network flow theory. 1 The Sloan Digital Sky Survey The Sloan Digital Sky Survey [is] a joint project of the Astrophysical Research Consortium... The go+ of the project, whi...

I examine possible futures for UV astronomy, in view of the past history and collected knowledge of the UV sky through various missions since the early days of Space Astronomy. The last all-sky survey has been by TD-1 in the early 1970s, resulting in reasonable mapping of discrete sources brighter than 9th mag (monochromatic, UV). Since TD-1, few advances were made in general knowledge of the U...

Planetary transits of bright stars, V < 10, offer the best opportunity for detailed studies of extra-solar planets, such as are already being carried out for HD209458b. Since these stars are rare, they should be searched over the entire sky. In the limits of zero read-out time, zero sky noise, and perfect optics, the sensitivity of an all-sky survey is independent of telescope aperture: for fix...

in a profoundly impressive verse in shahnameh, sky is likened to red ruby. the present paper is attempted to probe into the background of the conventional belief regarding the relationship between sky and stone, for the semantic structure of the verse is composed in such a way that it is not possible to consider this relationship as being a conceptualistic viewpoint so that one may establish so...

The AGILE γ-ray telescope (Tavani et al. 1998) will have a relatively uniform sensitivity over a very wide field of view. This allows to simultaneously monitor several AGN’s and to react quickly with multiwavelength observations in the case of flaring activity. The large cumulative sky coverage will also lead to a significant increase in the number of γ-ray emitting AGN’s known at the end of th...

Topography affects the fraction of direct and diffuse radiation received on a pixel and changes the sun–target–sensor geometry, resulting in variations in the observed radiance. Retrieval of surface–atmosphere properties from top of atmosphere radiance may need to account for topographic effects. This study investigates how such effects can be taken into account for top of atmosphere radiance m...

The solar radiation intercepted at a given location on the earth's surface is influenced by surface orientation and sky obstruction by surrounding topographic features. Viewshed models can be used to calculate sky obstruction for any given location on or above a complex topographic surface. We have developed an algorithm for rapid calculation of intercepted solar radiation using a combination o...

The etiology of mental retardation (MR), often presenting as developmental delay in childhood, is unknown in approximately one-half of cases. G-banding is the standard method for investigating those suspected of having a chromosomal etiology; however, detection of structural abnormalities is limited by the size and pattern of the G-bands involved. Rearrangements involving subtelomeric regions h...

Honeybees are known for their ability to use the sun's azimuth and the sky's polarization pattern for spatial orientation. Sky compass orientation in bees has been extensively studied at the behavioral level but our knowledge about the underlying neuronal systems and mechanisms is very limited. Electrophysiological studies in other insect species suggest that neurons of the sky compass system i...