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This paper describes the planned processing of monthly mean and monthly mean diurnal cycle flux products for the Geostationary Earth Radiation Budget (GERB) experiment. The use of higher-spatial-resolution flux estimates based on multichannel narrowband imager data to improve clear-sky sampling is investigated. Significant improvements in temporal sampling are found, leading to reduced temporal sampling errors and less dependence on diurnal models for the monthly mean products. The reduction in temporal sampling errors is found to outweigh any spatial sampling errors that are introduced. The resulting flux estimates are used to develop an improved version of the half-sine model that is used for the diurnal interpolation of clear-sky longwave fluxes over land in the Earth Radiation Budget Experiment (ERBE) and Clouds and the Earth's Radiant Energy System (CERES) missions. Maximum outgoing longwave radiation occurs from 45 rain to 1.5 h after local noon for most of the GERB field of view. Use of the ERBE half-sine model for interpolation therefore results in significant distortion of the diurnal cycle shape. The model that is proposed here provides a well-constrained fit to the true diurnal shape, even for limited clear-sky sampling, making it suitable for use in the processing of both GERB and CERES second-generation monthly mean clear-sky data products.

This paper reports on a new satellite sensor, the Geostationary Earth Radiation Budget (GERB) experiment. GERB is designed to make the first measurements of the Earth's radiation budget from geostationary orbit. Measurements at high absolute accuracy of the reflected sunlight from the Earth, and the thermal radiation emitted by the Earth are made every 15 min, with a spatial resolution at the subsatellite point of 44.6 km (north--south) by 39.3 km (east--west). With knowledge of the incoming solar constant, this gives the primary forcing and response components of the top-of-atmosphere radiation. The first GERB instrument is an instrument of opportunity on Meteosat-8, a new spin-stabilized spacecraft platform also carrying the Spinning Enhanced Visible and Infrared (SEVIRI) sensor, which is currently positioned over the equator at 3.5[degrees]W. This overview of the project includes a description of the instrument design and its preflight and in-flight calibration. An evaluation of the instrument performance after its first year in orbit, including comparisons with data from the Clouds and the Earth's Radiant Energy System (CERES) satellite sensors and with output from numerical models, are also presented. After a brief summary of the data processing system and data products, some of the scientific studies that are being undertaken using these early data are described. This marks the beginning of a decade or more of observations from GERB, as subsequent models will fly on each of the four Meteosat Second Generation satellites.

Interspecies hybrids between distinct species of the genus Xiphophorus are often used in varied research investigations to identify genomic regions associated with the inheritance of complex traits. There are 24 described Xiphophorus species and a greater number of pedigreed strains; thus, the number of potential interspecies hybrid cross combinations is quite large. Previously, select Xiphophorus experimental crosses have been shown to exhibit differing characteristics between parental species and among the hybrid fishes derived from crossing them, such as widely differing susceptibilities to chemical or physical agents. For instance, genomic regions harboring tumor suppressor and oncogenes have been identified via linkage association of these loci with a small set of established genetic markers. The power of this experimental strategy' is related to the number of genetic markers available in the Xiphophorus interspecies cross of interest. Thus, we have undertaken the task of expanding the suite of easily scored markers by characterization of Xiphophorus microsatellite sequences. Using a cross between Xiphophorus maculatus and X. andersi, we report a linkage map predominantly composed of microsatellite markers. All 24 acrocentric chromosome sets of Xiphophorus are represented in the assembled linkage map with an average intergenomic distance of 7.5 cM. Since both male and female [F.sub.1] hybrids were used to produce backcross progeny, these recombination rates were compared between 'male' and 'female' maps. Although several genomic regions exhibit differences in map length, male- and female-derived maps are similar. Thus Xiphophorus, in contrast to zebrafish, Danio rerio, and several other vertebrate species, does not show sex-specific differences in recombination. The microsatellite markers we report can be easily adapted to any Xiphophorus interspecies and some intraspecies crosses, and thus provide a means to directly compare results derived from independent experiments.

The study concerning sequence typing for identification of ET-5 complex of meningococci with different antigenic characteristics is discussed. Three subpopulations within ET-5 that caused disease outbreak in the United Kingdom in the late 1980s have been identified.

A method is described for the retrieval of cirrus cloud temperature and optical depth using thermal infrared data from the Along-Track Scanning Radiometer. The method utilizes above-cloud and nearby clear-sky thermal infrared data at a single wavelength and two different viewing angles and assumes that the cirrus cloud is nonscattering, isothermal, and semitransparent. The sensitivity of the method to small uncertainties in the input parameters is calculated. The effect on the retrieval of vertical inhomogeneity is investigated using idealized models of cirrus cloud vertical structure. It is shown that a vertical temperature structure within the cloud, alone and in conjunction with vertical inhomogeneity in absorption coefficient, can cause large errors in the retrieved quantities for a wide range of cloud types. However, these investigations show that retrieved quantities remain within usable limits for the majority of expected cirrus clouds. For example, for clouds with a lapse rate of 9 K [km.sup.-1] and a linear absorption coefficient profile with gradient ranging from -2 to +2, optical depth can be retrieved to an accuracy of better than 20% and temperature to within 10 K of the midcloud temperature, for clouds of thickness 2 km or less and optical depths between 0.8 and 4.