Ibvs and the long-term monitoring of behaviour of variable stars

Roles of the Information Bulletin on Variable Stars (IBVS) in servicing some of the information needs of observers of variable stars are briefly summarized.     

Modelling the hydrological response of mediterranean catchments,Prades, Catalonia. The use of distributed models as aids to hypothesis formulation

This paper attempts to extend the physical arguments underlying the distributed TOPMODEL concepts in an application to the strongly seasonal contributing area responses in two adjacent small mediterranean catchments in the Prades region of Catalonia, Spain. A perceptual model of hydrological response in these catchments is used to suggest possible modifications of the model in a hypothesis testing framework, including an attempt to modify the topographic index approach to reflect the expansion of the effective area of subsurface flow during the wetting-up sequence. It is found that slight improvements in modelling efficiency are possible but that different model parameter distributions are appropriate for different parts of the record. The model was much more successful for the catchment producing the higher runoff volumes. © 1997 John Wiley & Sons, Ltd.     

Magnetisation of titanomagnetites from Bulgarian basalts

A number of basalt samples containing titanomagnetites, with varying degrees and modes of oxidation, have been collected from 13 sites in northern Bulgaria, the degree of oxidation being determined from Curie point and lattice parameter determination. The stability of natural remanent magnetization and artificially induced thermoremanences (TRM) has been studied in an attempt to determine whether the oxidized rocks carry a TRM inherited from their original, unoxidized state. From the samples studied, it appears that the intensity and direction of the original TRM's are retained, but that there is some loss in stability.     

Questions in photoelectric photometry

The paper reviews generally well-known, though still frequently overlooked, procedural points in photoelectric photometry. Some examples, which point up the value of high photometric precision, are included.