Studies on a Group of Silicon Carbide Structures

Morphological and structural details of silicon carbide type 141R are given. This polymorph, having a structure represented by the zigzag sequence 3333333333333332, is a member of the `3...2' rhombohedral series proposed by Ramsdell [Am. Mineralogist 32, 64 (1947)].A detailed study of the `3...2' series is undertaken, resulting in an empirical mechanism which can be used for the direct determination of the structure of any member of this series. Using this means the structure of the new polymorph 393R is suggested.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/69640/2/JCPSA6-22-12-1977-1.pd

Criminal History Enhancements Sourcebook

Criminal history scores make up one of the two most significant determinants of the punishment an offender receives in a sentencing guidelines jurisdiction. While prior convictions are taken into account by all U.S. sentencing systems, sentencing guidelines make the role of prior crimes more explicit by specifying the counting rules and by indicating the effect of prior convictions on sentence severity. Yet, once established, criminal history scoring formulas go largely unexamined. Moreover, there is great diversity across state and federal jurisdictions in the ways that an offender's criminal record is considered by courts at sentencing. This Sourcebook brings together for the first time information on criminal history enhancements in all existing U.S. sentencing guidelines systems. Building on this base, the Sourcebook examines major variations in the approaches taken by these systems, and identifies the underlying sentencing policy issues raised by such enhancements.The Sourcebook contains the following elements:A summary of criminal history enhancements in all guidelines jurisdictions;An analysis of the critical dimensions of an offender's previous convictions;A discussion of the policy options available to commissions considering amendments to their criminal history enhancements;A bibliography of key readings on the role of prior convictions at sentencing

Flora of an unusually diverse old growth forest in the southeastern Adirondacks

A lowland, virgin white pine-hemlock stand and associated old-growth habitats were studied at Pack Forest Preserve, Warren County, NY. An area of 48.1 acres, interrupted only by nature trails, has white pines up to 58 inches in diameter, and supports 355 native plant species-an unexpectedly high number, considering its location in the climatically severe Adirondack Mountains. This minimally disturbed old-growth forest and its associated wetlands are not only diverse, but essentially weed-free, making them ideal for future ecological research, botanical teaching and monitoring activities

Quasispecies evolution in general mean-field landscapes

I consider a class of fitness landscapes, in which the fitness is a function of a finite number of phenotypic "traits", which are themselves linear functions of the genotype. I show that the stationary trait distribution in such a landscape can be explicitly evaluated in a suitably defined "thermodynamic limit", which is a combination of infinite-genome and strong selection limits. These considerations can be applied in particular to identify relevant features of the evolution of promoter binding sites, in spite of the shortness of the corresponding sequences.Comment: 6 pages, 2 figures, Europhysics Letters style (included) Finite-size scaling analysis sketched. To appear in Europhysics Letter

Market Forces and the Public Good: Competition Among Hospitals and Provision of Indigent Care

The research presented here focuses on the impact of competitive forces on the provision of social or merit goods by non-profit hospitals. We specifically examine the behavior of altruistic non-profit hospitals in the supply of charity care. The effects of competitive pressures and past charity care provision on the supply of philanthropic donations to nonprofit hospitals are also examined. Empirical models of the supply of donations and charity care are specified and estimated using data on nonprofit hospitals in Florida for the years 1980-1984. The coefficient estimates imply strong income effects in the charity care supply equations. This raises the possibility that competitive pressures and limits on hospital payments, under public insurance programs, may reduce the supply of indigent care. The results from the supply of donations models suggest that philanthropic donations will alleviate the competitive pressures to a small degree.

Simultaneous real-time visible and infrared video with single-pixel detectors

Conventional cameras rely upon a pixelated sensor to provide spatial resolution. An alternative approach replaces the sensor with a pixelated transmission mask encoded with a series of binary patterns. Combining knowledge of the series of patterns and the associated filtered intensities, measured by single-pixel detectors, allows an image to be deduced through data inversion. In this work we extend the concept of a ‘single-pixel camera’ to provide continuous real-time video at 10 Hz , simultaneously in the visible and short-wave infrared, using an efficient computer algorithm. We demonstrate our camera for imaging through smoke, through a tinted screen, whilst performing compressive sampling and recovering high-resolution detail by arbitrarily controlling the pixel-binning of the masks. We anticipate real-time single-pixel video cameras to have considerable importance where pixelated sensors are limited, allowing for low-cost, non-visible imaging systems in applications such as night-vision, gas sensing and medical diagnostics

Self-gravitating fragmentation of eccentric accretion disks

We consider the effects of eccentricity on the fragmentation of gravitationally unstable accretion disks, using numerical hydrodynamics. We find that eccentricity does not affect the overall stability of the disk against fragmentation, but significantly alters the manner in which such fragments accrete gas. Variable tidal forces around an eccentric orbit slow the accretion process, and suppress the formation of weakly-bound clumps. The "stellar" mass function resulting from the fragmentation of an eccentric disk is found to have a significantly higher characteristic mass than that from a corresponding circular disk. We discuss our results in terms of the disk(s) of massive stars at ~0.1pc from the Galactic Center, and find that the fragmentation of an eccentric accretion disk, due to gravitational instability, is a viable mechanism for the formation of these systems.Comment: 9 pages, 7 figures. Accepted for publication in Ap