Ore-reserve estimations of deposits with low mineral concentrations, such as those of copper, gold and tin, are usually made on the assumption that the grades follow a lognormal distribution. Multiple mineralization or reworking of a deposit may have modified the simple distribution expected — producing an overall distribution of grades which can be adequately described by a mixture of lognorma...

The MareNostrum Universe is one of the largest cosmological SPH simulation done so far. It consists of 1024 dark and 1024 gas particles in a box of 500 h Mpc on a side. Here we study the shapes and spins of the dark matter and gas components of the 10,000 most massive objects extracted from the simulation as well as the gas fraction in those objects. We find that the shapes of objects tend to b...

The effect of the microstructure on the electromigration failure development is analyzed. We investigate the influence of the statistical distribution of copper grain sizes on the electromigration time to failure distribution. Also, the effect of the microstructure on the formation and development of an electromigration-induced void is studied by simulation and the results are compared with exp...

It has been observed that return distributions in general and interest rates in particular exhibit skewness and kurtosis that are inadequately modeled by the lognormal distribution. We have modeled the skewness and kurtosis of the short rate using the g-and-h distribution and Generalized Beta Distribution of the Second Kind (GB2) and compare their performance. The g-and-h distribution is a func...

The problem of assessing occupational exposure using the mean of a lognormal distribution is addressed. The novel concepts of generalized p-values and generalized confidence intervals are applied for testing hypotheses and computing confidence intervals for a lognormal mean. The proposed methods perform well, they are applicable to small sample sizes, and they are easy to implement. Power studi...

1. Frequency of singletons - species represented by single individuals - is anomalously high in most large tropical arthropod surveys (average, 32%). 2. We sampled 5965 adult spiders of 352 species (29% singletons) from 1 ha of lowland tropical moist forest in Guyana. 3. Four common hypotheses (small body size, male-biased sex ratio, cryptic habits, clumped distributions) failed to explain sing...

Preliminary investigation on the feasibility of size selective passive sampling for atmospheric particles was undertaken through laboratory simulated and outdoor sampling. The passive samplers used in the research were improved from passive sampler used for sampling atmospheric organic contaminants. Sampled particle size distribution was analyzed by MasterSizer 2000 laser particle size analyzer...

Associated with a parameterization for the three-parameter lognormal distribution, algorithm was proposed by Komori and Hirose (2004), which can find a local maximum likelihood (ML) estimate surely if it exists. Nevertheless, by Vera and DiazGarcia (2008) it was shown that performance in finding a local ML estimate deteriorated by adopting the parameterization only and using other algorithm. In...