Contributions of the founders of Craig Colony to epileptology and public care of epileptics: 1890-1915

Craig Colony in Sonyea, New York, was America's first comprehensive public epilepsy center. The background to its establishment (the first patients were admitted in 1896) and its role as a model for other institutions is described. The history of the first 25 years of the Colony is recounted and the contributions to epileptology, and the legacy to health care, of the founders--William Pryor Letchworth, Frederick Peterson, Roswell Park, William P. Spratling and Frederick Munson--are assessed.     

Character and Age of Lateritic Weathering at Jervis Bay,Southern New South Wales

Lateritic profiles near Jervis Bay developed under humid temperate climates on a surface of considerable relief. δ¹⁸O and TL dating of these profiles indicates that their ages range from Late Mesozoic-Early Tertiary to Late Pleistocene. These profiles thus demonstrate a complexity of development far greater than that allowed for in traditional explanations which attributed lateritic weathering to the effects of tropical climates on Middle Tertiary erosional surfaces.     

ENERGY DISPERSIVE X-RAY FLUORESCENCE ANALYSIS OF ANCIENT COPPER ALLOYS: EMPIRICAL VALUES FOR PRECISION AND ACCURACY

Energy dispersive X-ray fluorescence (EDXRF) analyses are compared with neutron activation as well as atomic absorption analyses of ancient copper-based alloys in order to examine their accuracy and to estimate realistic values for precision and sensitivity of EDXRF. The results show that it is possible to obtain reliable data of the surface composition of objects non-destructively. Better results for bulk composition are usually obtained with drill samples where the sensitivity of the method is at least competitive with atomic absorption spectroscopy with flame atomization.     

Geographically Weighted Regression: A Method for Exploring Spatial Nonstationarity

Spatial nonstationarity is a condition in which a simple “global” model cannot explain the relationships between some sets of variables. The nature of the model must alter over space to reflect the structure within the data. In this paper, a technique is developed, termed geographically weighted regression, which attempts to capture this variation by calibrating a multiple regression model which allows different relationships to exist at different points in space. This technique is loosely based on kernel regression. The method itself is introduced and related issues such as the choice of a spatial weighting function are discussed. Following this, a series of related statistical tests are considered which can be described generally as tests for spatial nonstationarity. Using Monte Carlo methods, techniques are proposed for investigating the null hypothesis that the data may be described by a global model rather than a non-stationary one and also for testing whether individual regression coefficients are stable over geographic space. These techniques are demonstrated on a data set from the 1991 U.K. census relating car ownership rates to social class and male unemployment. The paper concludes by discussing ways in which the technique can be extended.     

COMPOSITIONAL INHOMOGENEITY OF SEDIMENTS AND ITS POTENTIAL EFFECTS ON DOSE RATE ESTIMATION FOR ELECTRON SPIN RESONANCE DATING OF TOOTH ENAMEL

We present results of particle size and radioactivity analyses of sediment samples collected from five sites with different burial environments. The uranium, thorium and potassium concentrations in the five sample sets are shown to vary with particle size. The potential effects of the observed size-dependent variations on electron spin resonance (ESR) dating of tooth enamel are assessed using two hypothetical models. Our results show that any bias to relatively fine fractions could result in a significant overestimation of the total environmental dose rate, leading to an underestimation of the calculated ESR age.