A detailed study of the transformations of the element phosphorus has been carried out at high hydrostatic pressures and at elevated temperatures. This has resulted in the discovery of a new modification of phosphorus, which is noncrystalline in structure and black in color. Its properties have been investigated to a certain extent. Some new calorimetric data are described which shed light on the question of the relative thermodynamic stabilities of this and the other forms of phosphorus.

We have studied the effectiveness of beta heating on driving a deuterium–tritium (DT) ice layer toward uniformity within spherical inertial fusion targets. Beta heating results from the deposition of energy from the beta particles from the tritium decay in these targets. These targets are enclosed in a constant temperature environment. This study first considered a one-dimensional heat transfer model of an idealized target, geometry, and environment. We concluded that beta energy deposition can drive a nonuniform DT ice layer towards uniformity. The maximum rate at which this redistribution can occur is given by dδ/dt=δ̇=−δ/θTC, where δ=DT ice thickness in excess of that for a uniform layer and θTC=a time constant ≊1500 s. This translates to a factor of 10 reduction in nonuniformity every hour. We also evaluated, and continue to do so, the consequences of deviations from the idealized case assumptions and the selection of certain experimental parameters, on the actual behavior of DT ice in such cryogenic targets. The status of this work is such that we have confidence in the use of beta heating to drive the DT ice toward uniformity for reactor-size targets (∼1 mm and larger in diameter).

An x-ray powder analysis of Rbl made at 4500 kg/cm 2 pressure and room temperature shows the crystal form of Rbl to be body-centered cubic under these conditions. The lattice constant is 4.33 5 A. The volume change from the face-centered lattice which is stable below 4000 atmospheres is 0.037 cm 3 per gram. This is about 0.009 cm 3 per gram greater than Bridgman's piston displacement value and the difference may be significant.With the exception of the fluorides, all of the rubidium and potassium halides undergo polymorphic transformations under pressure, which in the light of the present knowledge of Rbl are assumed to be of the face-centered to body-centered type. The method of Born and Mayer is used to calculate the lattice constants for both face-and body-centered types of each halide at the experimentally known temperature and pressure of equilibrium. From these the volume changes of the transformation are computed. They are found to agree quantitatively with the experimental values. Theoretical values for the transition pressure are also given. These are confirmed by experiment only in a qualitative manner, but the method may be used to explain, for instance, the nonoccurrence of transitions in the sodium halides up to 50,000 atmospheres. Similar calculations are made for Agl, the crystal form of which has been previously shown by the author to be face-centered cubic at pressures beyond 3000 kg/cm 2 .

Of 6 million ha of prairie that once covered northern and western Missouri, <36,500 ha remain, with planted, managed, and restored grasslands comprising most contemporary grasslands. Most grasslands are used as pasture or hayfields. Native grasses largely have been replaced by fescue (Festuca spp.) on most private lands (almost 7 million ha). Previously cropped fields set aside under the Conservation Reserve Program (CRP) varied from a mix of cool-season grasses and forbs, or mix of native warm-season grasses and forbs, to simple tall-grass monocultures. We used generalized linear mixed models and distance sampling to assess abundance of 8 species of breeding grassland birds on 6 grassland types commonly associated with farm practices in Missouri and located in landscapes managed for grassland-bird conservation. We selected Bird Conservation Areas (BCAs) for their high percentage of grasslands and grassland-bird species, and for <5% forest cover. We used an information-theoretic approach to assess the relationship between bird abundance and 6 grassland types, 3 measures of vegetative structure, and 2 landscape variables (% grassland and edge density within a 1-km radius). We found support for all 3 levels of model parameters, although there was less support for landscape than vegetation structure effects likely because we studied highpercentage-grassland landscapes (BCAs). Henslow's sparrow (Ammodramus henslowii) counts increased with greater percentage of grassland, vegetation height-density, litter depth, and shrub cover and lower edge density. Henslow's sparrow counts were greatest in hayed native prairie. Dickcissel (Spiza americana) counts increased with greater vegetation height-density and were greatest in planted CRP grasslands. Grasshopper sparrow (A. savannarum) counts increased with lower vegetation height, litter depth, and shrub cover. Based on distance modeling, breeding densities of Henslow's sparrow, dickcissel, and grasshopper sparrow in the 6 grassland types ranged 0.9-2.6, 1.4-3.2, and 0.1-1.5 birds/ha, respectively. We suggest different grassland types and structures (vegetation height, litter depth, shrub cover) are needed to support priority grassland-bird species in Missouri. ß 2011 The Wildlife Society.

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