Extragalactic database. VII Reduction of astrophysical parameters

The Lyon-Meudon Extragalactic database (LEDA) gives a free access to the main astrophysical parameters for more than 100,000 galaxies. The most common names are compiled allowing users to recover quickly any galaxy. All these measured astrophysical parameters are first reduced to a common system according to well defined reduction formulae leading to mean homogeneized parameters. Further, these parameters are also transformed into corrected parameters from widely accepted models. For instance, raw 21-cm line widths are transformed into mean standard widths after correction for instrumental effect and then into maximum velocity rotation properly corrected for inclination and non-circular velocity. This paper presents the reduction formulae for each parameter: coordinates, morphological type and luminosity class, diameter and axis ratio, apparent magnitude (UBV, IR, HI) and colors, maximum velocity rotation and central velocity dispersion, radial velocity, mean surface brightness, distance modulus and absolute magnitude, and group membership. For each of these parameters intermediate quantities are given: galactic extinction, inclination, K-correction etc.. All these parameters are available from direct connexion to LEDA (telnet lmc.univ-lyon1.fr, login: leda, no passwd OR http://www-obs.univ-lyon1.fr/leda ) and distributed on a standard CD-ROM (PGC-ROM 1996) by the Observatoire de Lyon via the CNRS (mail to [email protected]).Comment: 13 pages, 12 figures. The CDROM of the extragalactic database LEDA is available by mailing to: [email protected]

An image database. II. Catalogue between

A preliminary list of 68.040 galaxies was built from extraction of 35.841 digitized images of the Palomar Sky Survey (Paper I). For each galaxy, the basic parameters are obtained: coordinates, diameter, axis ratio, total magnitude, position angle. On this preliminary list, we apply severe selection rules to get a catalog of 28.000 galaxies, well identified and well documented. For each parameter, a comparison is made with standard measurements. The accuracy of the raw photometric parameters is quite good despite of the simplicity of the method. Without any local correction, the standard error on the total magnitude is about 0.5 magnitude up to a total magnitude of BT=17. Significant secondary effects are detected concerning the magnitudes: distance to plate center effect and air-mass effect

ATP-sensitive potassium channels in health and disease

The ATP-sensitive potassium (KATP) channel plays a crucial role in insulin secretion and thus glucose homeostasis. KATP channel activity in the pancreatic β-cell is finely balanced; increased activity prevents insulin secretion, whereas reduced activity stimulates insulin release. β-cell metabolism tightly regulates KATP channel gating, and if this coupling is perturbed, two distinct disease states can result. Diabetes occurs when the KATP channel fails to close in response to increased metabolism, whereas congenital hyperinsulinism results when KATP channels remain closed even at very low blood glucose levels. In general there is a good correlation between the magnitude of KATP current and disease severity. Mutations that cause a complete loss of KATP channels in the β-cell plasma membrane produce a severe form of congenital hyperinsulinism, whereas mutations that partially impair channel function produce a milder phenotype. Similarly mutations that greatly reduce the ATP sensitivity of the KATP channel lead to a severe form of neonatal diabetes with associated neurological complications, while mutations that cause smaller shifts in ATP sensitivity cause neonatal diabetes alone. This chapter reviews our current understanding of the pancreatic β-cell KATP channel and highlights recent structural, functional, and clinical advances