[show abstract][hide abstract] ABSTRACT: Russia's boreal forests host 11% of the world's live forest biomass. They play a critical role in Russia's economy, as well as in stabilising the global climate.The boreal forests of Central and Western Siberia represent the largest unbroken tracts of forest in the world, and are listed as "Last Frontier Forests" by the World Resources Institute. The EU-funded SIBERIA project aimed at producing a forest map covering an area of 1.2 million square kilometres. Two operational Synthetic Aperture Radars (SAR) on board of the satellites ERS-1, ERS-2 and JERS-1 are used to provide remote sensing data. The objective was to combine data from two different wavelengths with SAR interferometry to deliver a large-scale forest map from SAR. The development of an appropriate classification algorithm proved difficult because of large variation in image features between images. An accuracy assessment of the classification results was carried out using spatial forest inventory data from several Russian Forestry Enterprises. Issues of geometric, radiometric, and classification accuracy are discussed and a method for accuracy assessment is presented.
[show abstract][hide abstract] ABSTRACT: The catalytic effect of charged micelles as manifested through the increased collision frequency between the counterions of an electrolyte in the presence of such micelles is explored by the Monte Carlo simulation technique and various theoretical approaches. The micelles and ions are pictured as charged hard spheres embedded in a dielectric continuum with the properties of water at 298 K with the charge on micelles varying from zero to z(m) = 50 negative elementary charges. Analytical theories such as (i) the symmetric Poisson-Boltzmann theory, (ii) the modified Poisson-Boltzmann theory, and (iii) the hypernetted-chain integral equation are applied and tested against the Monte Carlo data for micellar ions (m) with up to 50 negative charges in aqueous solution with monovalent counterions (c; z(c) = +1) and co-ions (co; z(co) = -1). The results for the counterion-counterion pair correlation function at contact, g(cc)(sigma(cc)), are calculated in a micellar concentration range from c(m) = 5 x 10(-)(6) to 0.1 mol/dm(3) with an added +1:-1 electrolyte concentration of 0.005 mol/dm(3) (for most cases), and for various model parameters. Our computations indicate that even a small concentration of a highly charged polyelectrolyte added to a +1:-1 electrolyte solution strongly increases the probability of finding two counterions in contact. This result is in agreement with experimental data. For low charge on the micelles (z(m) below -8), all the theories are in qualitative agreement with the new computer simulations. For highly charged micelles, the theories either fail to converge (the hypernetted-chain theory) or, alternatively, yield poor agreement with computer data (the symmetric Poisson-Boltzmann and modified Poisson-Boltzmann theories). The nonlinear Poisson-Boltzmann cell model results yield reasonably good agreement with computer simulations for this system.