Rocket-triggered lightning strikes and forest fire ignition

The following are presented: (1) background information on the rocket-triggered lightning project an Kennedy Space Center (KSC); (2) a summary of the forecasting problem; (3) the facilities and equipment available for undertaking field experiments at KSC; (4) previous research activity performed; (5) a description of the atmospheric science field laboratory near Mosquito Lagoon on the KSC complex; (6) methods of data acquisition; and (7) present results. New sources of data for the 1990 field experiment include measuring the electric field in the lower few thousand feet of the atmosphere by suspending field measuring devices below a tethered balloon, and measuring the electric field intensity in clouds and in the atmosphere with aircraft. The latter program began in July of 1990. Also, future prospects for both triggered lightning and forest fire research at KSC are listed

A Discrete Evolutionary Model for Chess Players' Ratings

The Elo system for rating chess players, also used in other games and sports, was adopted by the World Chess Federation over four decades ago. Although not without controversy, it is accepted as generally reliable and provides a method for assessing players' strengths and ranking them in official tournaments. It is generally accepted that the distribution of players' rating data is approximately normal but, to date, no stochastic model of how the distribution might have arisen has been proposed. We propose such an evolutionary stochastic model, which models the arrival of players into the rating pool, the games they play against each other, and how the results of these games affect their ratings. Using a continuous approximation to the discrete model, we derive the distribution for players' ratings at time $t$ as a normal distribution, where the variance increases in time as a logarithmic function of $t$. We validate the model using published rating data from 2007 to 2010, showing that the parameters obtained from the data can be recovered through simulations of the stochastic model. The distribution of players' ratings is only approximately normal and has been shown to have a small negative skew. We show how to modify our evolutionary stochastic model to take this skewness into account, and we validate the modified model using the published official rating data.Comment: 17 pages, 4 figure

Food fit for a Khan: Stable isotope analysis of the elite Mongol Empire cemetery at Tavan Tolgoi, Mongolia

The creation and expansion of the Mongol Empire during the thirteenth century A.D. brought with it many changes, both for the conquered peoples and for the conquerors themselves. Ruling elite Mongols in foreign lands imposed new customs onto their new subjects, but also adopted some of the characteristics of the cultures they ruled; these are topics of sustained and continuing research interest. Equally interesting but less well researched is what impact the Empire had on Mongols remaining in the Mongolian homeland. Historical sources suggest that the fruits of Empire would have flowed not only to remote Mongol capitals of the Empire but also back to Mongolia proper. Here we use dietary stable isotope analysis to assess whether the Empire brought large changes to the diet of either ruling elites or more common people in the Mongolian homeland. Carbon and nitrogen stable isotope ratios are measured in bone collagen from human and faunal remains from Tavan Tolgoi, a ruling elite cemetery in eastern Mongolia, and compared with ratios from lesser ranked people at the cemetery of Tsagaan chuluut. These are also compared with ratios from the Bronze Age cemetery of Ulaanzuukh, a post-Empire set of human remains, and modern and archaeological human and faunal remains from the wider region. The Tavan Tolgoi isotope ratios do differ from those of Tsagaan chuluut and Ulannzuukh. Comparison with isotope data from the wider region, however, suggests that the differences may be due to differing environmental conditions rather than dietary differences