This study analyses the sources of atrazine contamination in the Brusselian sandy aquifer of central Belgium. Atrazine has in the past been used for both agricultural and non-agricultural applications, but it is difficult to distinguish the contamination originating from these two sources. The spatial and temporal covariance of atrazine concentrations was studied by fitting semi-variogram model...

A new parametric (3-parameter) survival distribution, the lognormal-power function distribution, with flexible behaviour is introduced. Its hazard rate function can be either unimodal, monotonically decreasing or can exhibit a bathtub shape. Special cases include the lognormal distribution and the power function distribution, with finite support. Regions of parameter space where the various for...

We unify two approaches that have been taken to explain the non-Gaussian probability distribution functions (PDFs) obtained in measurements of longitudinal velocity differences in turbulence, and we apply our approach to Couette-Taylor turbulence data. The first approach we consider was developed by Castaing and co-workers, who obtained the non-Gaussian velocity difference PDF from a superposit...

The origin of the recently reported systematic bias in the spectroscopic temperature of galaxy clusters is investigated using cosmological hydrodynamical simulations. We find that the local inhomogeneities of the gas temperature and density, after corrected for the global radial profiles, have nearly a universal distribution that resembles the log-normal function. Based on this log-normal appro...

Supplementary material for estimation of a parametric function associated with the lognormal distribution Jiangtao Gou and Ajit C. Tamhane Department of Statistics, Northwestern University, Evanston, IL 60208, USA Department of Mathematics and Statistics, Hunter College, New York, NY 10065, USA Department of Industrial Engineering and Management Sciences, Northwestern University, Evanston, IL 6...

This paper examines the hypothesis that short run changes in tne U.S. size distribution of personal income have been systematically related to aggregate levels of output~ personal income~ and employment during the posh7ar period. Part one proposes a procedure for describing the size distribution of income. The observed distribution is approximated by a displaced lognormal distribution vmich cor...

By conventional wisdom, a feature that occurs too often or too rarely in a genome can indicate a functional element. To infer functionality from frequency, it is crucial to precisely characterize occurrences in randomly evolving DNA. We find that the frequency of oligonucleotides in a genomic sequence follows primarily a Pareto-lognormal distribution, which encapsulates lognormal and power-law ...

We develop and apply a multilevel modeling approach that is simultaneously capable of assessing multigroup and multiscale segregation in the presence of substantial stochastic variation that accompanies ethnicity rates based on small absolute counts. Bayesian MCMC estimation of a log-normal Poisson model allows the calculation of the variance estimates of the degree of segregation in a single o...

The small-scale turbulent dynamo in the high Prandtl number regime is described in terms of the one-point Fourier space correlators. The second-order correlator of this kind is the energy spectrum and it has been previously studied in detail. We examine the higher order k-space correlators, which contain important information about the phases of the magnetic wave packets and about the dominant ...

We analyze the temporal structure of long (T90 > 2sec) and short (T90 < 2sec) BATSE bursts. We find that: (i) In many short bursts δtmin/T ≪ 1 (where δtmin is the shortest pulse). This indicates that short bursts arise, like long ones, in internal shocks. (ii) In long bursts there is an excess of long intervals between pulses (relative to a lognormal distribution). This excess can be explained ...