near surface ozone in urban areas can be potentially hazardous for the city dwellers. as a secondary pollutant it can also be an indicator for other air pollutants as nitrogen oxides, nox and phenol acetate nitrate (pan). in this paper time and spatial variations of near surface ozone and the effective meteorological parameters influencing it concentrations, have been investigated for tehran fo...

We introduce the multiset sampler (MSS), a new Metropolis-Hastings algorithm for drawing samples from a posterior distribution. The MSS is designed to be effective when the posterior has the feature that the parameters can be divided into two sets: X, the parameters of interest and Y , the nuisance parameters. We contemplate a Metropolis-within-Gibbs sampler that iterates between X moves and Y ...

The counting of fibres on membrane filters could be facilitated by using size-selective samplers to exclude coarse particulate and fibres that impede fibre counting. Furthermore, the use of thoracic size selection would also remove the present requirement to discriminate fibres by diameter during counting. However, before thoracic samplers become acceptable for sampling fibres, their performanc...

Benthic macroinvertebrate fauna plays a major role in river ecosystems, especially those of tropical islands. Since there is no information on the distribution of benthic invertebrates along a Jamaican river, we report here on the composition of the benthic fauna of the Buff Bay river, on the Northern coast of Jamaica. A total of 14 samples were collected from five sites, using kick nets and a ...

Lattice-based public key cryptography often requires sampling from discrete Gaussian distributions. In this paper we present an efficient hardware implementation of a discrete Gaussian sampler with high precision and large tail-bound based on the Knuth-Yao algorithm. The Knuth-Yao algorithm is chosen since it requires a minimal number of random bits and is well suited for high precision samplin...

The Gibbs sampler, a Markov chain Monte Carlo (MCMC) method, has been applied to probability computation in statistical genetics since the late 1980's. But how well this algorithm works has yet to be investigated. Preliminary results presented by various researchers are very encouraging, but difficulties remain. Two of these difficulties are multimodality and reducibility, induced by complexiti...

Airborne skin exposure to allergens and irritants may cause dermatitis. There are few methods for assessing skin exposure to airborne particles. We have modified and tested a vacuuming sampler for removing particles from the skin. The sampler was compared with two other skin and surface exposure sampling techniques. These were based on surrogate skin (a patch sampler-adhesive tape on an optical...