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...

Cluster-field segregation and determination of physical parameters of the open clusters NGC 1750 and NGC 1758 were performed from CCD and photographic photometric and astrometric surveys previously published by the authors. Membership probabilities were computed to a brightness limit of R = 15 mag through a non-standard method in a fully nonparametric approach, using proper motions, positions a...

The aim of this work was to present a preliminary knowledge of the parasitic copepods of marine fish of Turkey. In this study, four parasitic crustaceans were reported from five different fish species found in Turkish seas: Lepeophtheirus europaensis (Zeddam, Berrebi, Renaud, Raibaut & Gabrion, 1988) was found on the gills of the European flounder, Platichtys flesus (Linnaeus, 1758 (Pleuronecti...

Carnivorous zooplankton is a key element to the energy transfer through the arctic food web, linking lipid rich herbivores to the top predators. We investigated the growth and lipid dynamic of the Arctic pelagic amphipod Themisto libellula in Kongsfjorden (Svalbard, 79°N) from May to October 2007. Additional samplings were performed in spring and summer 2006 and further north in Rijpfjorden (80...