Introduction to the Demography Volume

[Excerpt] This volume represents another effort by Research in the Sociology of Organizations to focus on a crucial issue in organizational sociology. In some of the previous volumes, we concentrated on organizations and professions (Volume 8, 1991), the structuring of participation in organizations (Volume 7, 1989), and the social psychological processes in organizations (Volume 3, 1984). This volume concentrates on one of the most important emerging issues in organizational sociology—the issue of organizational demography

The hard X-ray burst spectrometer event listing, 1980 - 1985

This event listing is a comprehensive reference for the hard X-ray bursts detected with the Hard X-Ray Burst Spectrometer on the Solar Maximum Mission from the time of launch on February 14, 1980 to September 1985. Over 8000 X-ray events were detected in the energy range from 30 to approx. 500 keV with the vast majority being solar flares. The listing includes the start time, peak time, duration and peak rate of each event

The hard X-ray burst spectrometer event listing 1980, 1981 and 1982

A comprehensive reference for the hard X-ray bursts detected with the Hard X-Ray Burst Spectrometer on the Solar Maximum Mission for the time of launch on February 14, 1980 to March 1983 is provided. Over 6300 X-ray events were detected in the energy range from 30 to approx 500 keV with the vast majority being solar flares. The listing includes the start time, peak time, duration and peak rate of each event

Microstructure of nanocrystalline diamond powders studied by powder diffractometry

High resolution x-ray diffraction peaks of diamond nanosize powders of nominal sizes ranging from 5 to 250 nm were analyzed and provided information on grain structure, average size of crystallites, and concentration of dislocations. Selected samples were heat treated at 1670 K at pressures 2.0 and 5.5 GPa or had surface modified by outgassing, heat treatment at vacuum conditions, and by controlled adsorption of gases. The apparent lattice parameter method was applied to characterize the structure of a shell-core model of nanosize particles. The multiple whole profile fitting provided information on crystallite sizes and density of dislocations. Population of dislocations increased with applied pressure, while strain and interplanar distances in the surface layers decreased. Adsorption of foreign gases on the grain surface modified the structure of the surface layers but did not affect dislocations near the center of the grains

The complete Hard X Ray Burst Spectrometer event list, 1980-1989

This event list is a comprehensive reference for all Hard X ray bursts detected with the Hard X Ray Burst Spectrometer on the Solar Maximum Mission from the time of launch on Feb. 14, 1980 to the end of the mission in Dec. 1989. Some 12,776 events were detected in the energy range 30 to 600 keV with the vast majority being solar flares. This list includes the start time, peak time, duration, and peak rate of each event

The hard X-ray burst spectrometer event listing 1980-1987

This event listing is a comprehensive reference for the Hard X-ray bursts detected with the Hard X-ray Burst Spectrometer on the Solar Maximum Mission from the time of launch 14 February 1980 to December 1987. Over 8600 X-ray events were detected in the energy range from 30 to approx. 600 keV with the vast majority being solar flares. The listing includes the start time, peak time, duration and peak rate of each event

Photorespiration: metabolic pathways and their role in stress protection

Photorespiration results from the oxygenase reaction catalysed by ribulose-1,5-bisphosphate carboxylase/ oxygenase. In this reaction glycollate-2-phosphate is produced and subsequently metabolized in the photorespiratory pathway to form the Calvin cycle intermediate glycerate-3-phosphate. During this metabolic process, CO2 and NH3 are produced and ATP and reducing equivalents are consumed, thus making photorespiration a wasteful process. However, precisely because of this ine¤ciency, photorespiration could serve as an energy sink preventing the overreduction of the photosynthetic electron transport chain and photoinhibition, especially under stress conditions that lead to reduced rates of photosynthetic CO2 assimilation. Furthermore, photorespiration provides metabolites for other metabolic processes, e.g. glycine for the synthesis of glutathione, which is also involved in stress protection. In this review, we describe the use of photorespiratory mutants to study the control and regulation of photorespiratory pathways. In addition, we discuss the possible role of photorespiration under stress conditions, such as drought, high salt concentrations and high light intensities encountered by alpine plants

Metastability in pressure-induced structural transformations of CdSe/ZnS core/shell nanocrystals

The kinetics and thermodynamics of structural transformations under pressure depend strongly on particle size due to the influence of surface free energy. By suitable design of surface structure, composition, and passivation it is possible, in principle, to prepare nanocrystals in structures inaccessible to bulk materials. However, few realizations of such extreme size-dependent behavior exist. Here we show with molecular dynamics computer simulation that in a model of CdSe/ZnS core/shell nanocrystals the core high pressure structure can be made metastable under ambient conditions by tuning the thickness of the shell. In nanocrystals with thick shells, we furthermore observe a wurtzite to NiAs transformation, which does not occur in the pure bulk materials. These phenomena are linked to a fundamental change in the atomistic transformation mechanism from heterogenous nucleation at the surface to homogenous nucleation in the crystal core. Our results suggest a new route towards expanding the range of available nanoscale materials