Comparing Caddo and Coles Creek Pottery Using Petrographic Analysis

Pottery classified as “Coles Creek Incised” is common both to the earliest Caddo sites along the Red River and to contemporary sites in the Lower Mississippi Valley. Although it often is suggested that Coles Creek pottery from the two regions can be distinguished by differences in paste, no detailed comparative studies have been carried out. An initial attempt to identify variation through the use of petrographic analysis was carried out by comparing 50 samples drawn from sites in northwest and central Louisiana. Although no sharp dichotomy was noted between the regions, the study identified distinctions that support the notion that most Coles Creek pottery was made locally and different technological traditions may be represented

Fragmentation of positronium in collision with He atoms

The absolute cross section for the fragmentation of positronium in collision with He atoms has been measured. The results are compared with available theories. The longitudinal energy distributions of positrons resulting from fragmentation have also been determined and are found to display a peak situated just below half the residual energy. This is suggestive of the occurrence of "electron loss to the continuum" in which the two residual charged particles lie in a low relative-velocity Coulomb-continuum state

Three-dimensional coating and rimming flow: a ring of fluid on a rotating horizontal cylinder

The steady three-dimensional flow of a thin, slowly varying ring of Newtonian fluid on either the outside or the inside of a uniformly rotating large horizontal cylinder is investigated. Specifically, we study “full-ring” solutions, corresponding to a ring of continuous, finite and non-zero thickness that extends all the way around the cylinder. In particular, it is found that there is a critical solution corresponding to either a critical load above which no full-ring solution exists (if the rotation speed is prescribed) or a critical rotation speed below which no full-ring solution exists (if the load is prescribed). We describe the behaviour of the critical solution and, in particular, show that the critical flux, the critical load, the critical semi-width and the critical ring profile are all increasing functions of the rotation speed. In the limit of small rotation speed, the critical flux is small and the critical ring is narrow and thin, leading to a small critical load. In the limit of large rotation speed, the critical flux is large and the critical ring is wide on the upper half of the cylinder and thick on the lower half of the cylinder, leading to a large critical load.\ud \ud We also describe the behaviour of the non-critical full-ring solution, and, in particular, show that the semi-width and the ring profile are increasing functions of the load but, in general, non-monotonic functions of the rotation speed. In the limit of large rotation speed, the ring approaches a limiting non-uniform shape, whereas in the limit of small load, the ring is narrow and thin with a uniform parabolic profile. Finally, we show that, while for most values of the rotation speed and the load the azimuthal velocity is in the same direction as the rotation of the cylinder, there is a region of parameter space close to the critical solution for sufficiently small rotation speed in which backflow occurs in a small region on the right-hand side of the cylinder

Her Time, His Time, or the Maid's Time: An Analysis of the Demand for Domestic Work

This paper analyzes households' demand for time inputs to domestic services, modeling simultaneously the decision to purchase services in the market and the time spent on weekend and weekday days by each partner on routine household chores. By focusing on cleaning, laundry, and ironing, we reduce the likelihood that preferences matter and increase the overlap with market services. Particular emphasis is placed on estimating the effects of prices, as captured by own and partner wages and the market price for domestic services. We exploit time-diary data for Great Britain and France, relying on cross-country comparisons to generalize our findings. The results indicate that prices strongly influence market purchases, and that maid service is a closer substitute for household time on weekends than weekdays, but is also correlated with 'her' weekday time. More generally, we find that women's wages have a stronger association with the inputs to domestic work than any other price measure.time use, domestic work, gender

Thermoviscous Coating and Rimming Flow

A comprehensive description is obtained of steady thermoviscous (i.e. with temperature-dependent viscosity) coating and rimming flow on a uniformly rotating horizontal cylinder that is uniformly hotter or colder than the surrounding atmosphere. It is found that, as in the corresponding isothermal problem, there is a critical solution with a corresponding critical load (which depends, in general, on both the Biot number and the thermoviscosity number) above which no ``full-film'' solutions corresponding to a continuous film of fluid covering the entire outside or inside of the cylinder exist. The effect of thermoviscosity on both the critical solution and the full-film solution with a prescribed load is described. In particular, there are no full-film solutions with a prescribed load M for any value of the Biot number when M is greater than or equal to M_{c0} divided by the square root of f for positive thermoviscosity number and when M is greater than M_{c0} for negative thermoviscosity number, where f is a monotonically decreasing function of the thermoviscosity number and M_{c0} = 4.44272 is the critical load in the constant-viscosity case. It is also found that when the prescribed load M is less than 1.50315 there is a narrow region of the Biot number - thermoviscosity number parameter plane in which backflow occurs

Studies of discharge mechanisms in high pressure gases-applications to high efficiency high power lasers

By measuring the absorption and emission cantinua of various states in the cesium/xenon molecule, the collisional rates critical in populating the alkali/rare gas excimer levels have been estimated. Cs atomic states that are weakly optically connected to ground have been shown to form excimer levels that are attractive as potential dissociation lasers. In particular, the (Cs/7 2S/Xe) excited molecule appears promising as a source of high energy laser radiation due to its large dissociation energy, stimulated emission cross section, and small population inversion densities. Monitoring of the optically pumped Cs2 molecular absorption profile in the presence of xenon shows a drastic change with increasing xenon pressure for the Cs2C band. Dominant absorption at large xenon densities is centered around approximately 6380 A as opposed to 6300 A for lower perturber pressure

Development of Turbulence-Measuring Equipment

Hot wire turbulence-measuring equipment has been developed to meet the more stringent requirements involved in the measurement of fluctuations in flow parameters at supersonic velocities. The higher mean speed necessitates the resolution of higher frequency components than at low speed, and the relatively low turbulence level present at supersonic speed makes necessary an improved noise level for the equipment. The equipment covers the frequency range from 2 to about 70,000 cycles per second. Constant-current operation is employed. Compensation for hot-wire lag is adjusted manually using square-wave testing to indicate proper setting. These and other features make the equipment adaptable to all-purpose turbulence work with improved utility and accuracy over that of older types of equipment. Sample measurements are given to demonstrate the performance

Absolute differential positronium-formation cross sections

The first absolute experimental determinations of the differential cross-sections for the formation of ground-state positronium are presented for He, Ar, H2 and CO2 near 0○. Results are compared with available theories. The ratio of the differential and integrated cross-sections for the targets exposes the higher propensity for forward-emission of positronium formed from He and H2