Ceremonial architecture of late precontact (A.D. 600-1500) societies of Puerto Rico consists of stone-lined plazas and ball courts (bateys,). Archaeologists use these structures to signify the onset of hierarchical “chiefly” polities and to interpret their regional organization. Problematically, little consideration is given to the costs of their physical construction and the associated organizational implications at local and regional scales. In this paper, we use data gathered through geoarchaeological field investigations to develop labor estimates for the plaza and bateys at the site of Tibes—one of the largest precolumbian ceremonial centers in Puerto Rico. The estimates provide a basis for addressing how these features were constructed at the site and are considered within the broader organizational contexts of incipient polities in the island's south-central region between A.D. 600 and A.D. 1200.

Chickpea production in marginal (<600 mm annual rainfall) areas of the northern cropping region in eastern Australia is considered to be constrained by low rainfall, soils with low plant available water capacity (PAWC), subsoil salinity, low plant stature and poor fruit set. This study examines these constraints to assess the magnitude of their impact and if agronomic practices can improve potential production. Over three years a total of 42 commercial chickpea crops were monitored following a participatory action research approach focusing on perceived production constraints. Subsoil salinity significantly reduced PAWC for chickpea compared to wheat. However, PAWC for chickpeas from the majority of sites monitored was comparable to other areas. The supply of water between flowering and maturity was significantly related to yield. The agronomic practice of levelling following deep planting improved the lowest pod height by 10 cm and plant stresses experienced during flowering caused a 50 % loss of potential fruit. Constraints impacting on the supply and storage of soil water could be minimized by selecting paddocks with low chloride levels in the upper layers and sowing crops when the available soil water is greater than 100 mm. Reducing fruit loss at flowering has the potential to improve yields significantly. The mechanisms behind this loss were not identified but are worthy of further research.

In point-to-plane corona discharges in air, the collisions of charged particles with neutral particles induce a gas movement between the point to the plane called electric wind. A one-dimensional model of the neutral particle velocity along the discharge axis and between the electrodes is first developed. Laser Doppler Anemometry is used to measure the axial velocity profile of the gas between the electrodes. Discrepancies between experimental results and predictions of the on-axis velocity are discussed. Finally, the measured velocity profile compares quite well with a cos5θ distribution. Significant differences between measured and cos5θ profiles are observed near the discharge axis which could be attributed to the presence of seeding particles.  

The DJEHUTY project is an intensive effort at the Lawrence Livermore National Laboratory (LLNL) to produce a general purpose 3-D stellar structure and evolution code to study dynamic processes in whole stars.