Methods for the evaluation and synthesis of multiple sources of information applied to nuclear computer codes

This work is devoted to methods used to evaluate and synthesize information given by multiple sources about a variable which true value is not precisely known. We first recall probabilistic and possibilistic approaches to solve the problem. Each approach offers a formal setting to evaluate, synthesize and analyze information coming from multiple sources. They are then applied to the results of uncertainty studies performed in the framework of BEMUSE project.     

Polyprenols in leaves of fruit-trees of Rosaceae family

In leaves of various species of fruit-trees belonging to the Rosaceae family, large amounts of polyprenyl acetates (0.5-5.0% of dry weight) were found. Discrete constant differences of polyprenol spectrum characteristic of each genus studied: Malus, Prunus and Pyrus were observed. In each species poly-cis-prenols composed of 19 and 20 isoprene units were predominating. In one of the 23 studied species (Prunus incisa) a fraction of long-chain polyprenols composed of 35-45 isoprene units was also present. It seems that this type of unusually long-chain polyprenols could occur also in other plants of the Rosaceae family.     

Can the Sun's Direction be Estimated from an Image Prior to the Computation of Object Shape?

Various computational techniques have been developed that performreasonably well in inferring shape from shading. However, thesetechniques typically require substantial prerequisite information ifthey are to evolve an estimate of surface shape. It is thereforeinteresting to consider how depth might be inferred from shadinginformation without prior knowledge of various scene conditions. Oneapproach has been to undertake a pre-processing step ofestimating the light-source direction, thereby providing input tothe computation of shape from shading. In this paper, we presentevidence that a versatile light-source-direction estimator isunattainable, and propose that, in the absence of domain-specificknowledge, shape and light-source direction should be determined ina coupled manner     

Divergent pattern of polyisoprenoid alcohols in the tissues of <Emphasis Type="Italic">Coluria geoides</Emphasis>: A new electrospray lonization MS approach

Polyisoprenoid alcohols of the plant Coluria geoides were isolated and analyzed by HPLC with UV detection to determine the nature of the polyprenol and dolichol mixture in the organs studied. In roots, a family of dolichols (Dol-15 to Dol-23, with Dol-16 dominating, where Dol-n is dolichol composed of n isoprene units) was accompanied by traces of polyprenols of similar chain lengths, whereas in hairy roots grown in vitro, identical patterns with a slightly broader chain-length range were found. Conversely, in leaves and seeds polyprenols were the dominant form, and their pattern was shifted toward longer chains (maximal content of Pren-19, where Pren-n is polyprenol composed of n isoprene units). Interestingly, the pattern of dolichols in seeds and leaves (in which Dol-17 dominated) was similar to that found in roots. Structures of the dolichols and polyprenols isolated were confirmed by the application of a new HPLC/electrospray ionization-MS method, which also offers a much higher sensitivity in detection of these compounds compared to a UV detector. The highest sensitivity was obtained when the [M+Na]⁺ ions of polyprenols and dolichols were recorded in the selected ion monitoring mode and a small amount of sodium acetate solution was added post-column to enhance the formation of these ions in an electrospray ion source.     

Sampling Minimal Subsets with Large Spans for Robust Estimation

When sampling minimal subsets for robust parameter estimation, it is commonly known that obtaining an all-inlier minimal subset is not sufficient; the points therein should also have a large spatial extent. This paper investigates a theoretical basis behind this principle, based on a little known result which expresses the least squares regression as a weighted linear combination of all possible minimal subset estimates. It turns out that the weight of a minimal subset estimate is directly related to the span of the associated points. We then derive an analogous result for total least squares which, unlike ordinary least squares, corrects for errors in both dependent and independent variables. We establish the relevance of our result to computer vision by relating total least squares to geometric estimation techniques. As practical contributions, we elaborate why naive distance-based sampling fails as a strategy to maximise the span of all-inlier minimal subsets produced. In addition we propose a novel method which, unlike previous methods, can consciously target all-inlier minimal subsets with large spans.     

Bioavailability of heavy metals from polluted soils to plants

The aim of this work was to estimate, on the basis of soil extraction procedures, whether a given soil is suitable for cultivation of plants used as food or feed. The paper discusses the transfer of metal ions (As, Cd, Cr, Cu, Hg, Mn, Ni, Pb, Zn) from contaminated soils to plants in terms of transfer factors (TF). The knowledge of transfer factors for a given element should enable prediction, before plants are sowed, whether a given soil is suitable for the cultivation of plants for consumption purposes. TF can only be evaluated when a linear relationship is observed between soil and plant composition for a given element. Such a relationship is rarely observed between the total soil content of a given metal and that of the plant. For this reason, it was necessary to develop an extraction procedure that would represent the content of metal available to plants during growing season. Several extracting agents were tested. The extracting agent that fulfilled these criteria was 2% (w/v) ammonium citrate. Statistically significant correlation coefficients were determined between the citrate-soluble fraction of soil and content in plant in the case of all the elements studied, except Ni. If a statistically significant correlation exists, it is then possible to evaluate the soil-plant transfer factor for a given metal in plants.     

Rationalising the Renormalisation Method of Kanatani

The renormalisation technique of Kanatani is intended to iteratively minimise a cost function of a certain form while avoiding systematic bias inherent in the common method of minimisation due to Sampson. Within the computer vision community, the technique has generally proven difficult to absorb. This work presents an alternative derivation of the technique, and places it in the context of other approaches. We first show that the minimiser of the cost function must satisfy a special variational equation. A Newton-like, fundamental numerical scheme is presented with the property that its theoretical limit coincides with the minimiser. Standard statistical techniques are then employed to derive afresh several renormalisation schemes. The fundamental scheme proves pivotal in the rationalising of the renormalisation and other schemes, and enables us to show that the renormalisation schemes do not have as their theoretical limit the desired minimiser. The various minimisation schemes are finally subjected to a comparative performance analysis under controlled conditions.     

The diversity of polyprenol pattern in leaves of fruit trees belonging to Rosaceae and Cornaceae

The polyprenol pattern in leaves of fruit trees belonging to the Rosaceae (genera: Prunus, Malus) and Cornaceae (genus: Cornus) families is presented. The content of polyprenyl acetates varied within plant species between 10-50 mg per gram of dry weight. In genus Prunus, Cornus and in representatives of species Malus domestica, a mixture of polyprenols composed of 18, 19, 20, 21 isoprene units was found. In six species of genus Prunus (sour-cherry): P. serrulata-spontanea, P. yedoensis, P. fruticosa. P. kurilensis, P. subhirtella and P. incisa the presence of a second polyprenol family, i.e. the group of prenologues consisting of prenol -35, -36, -37, etc. up to -42 was detected.     

Utilization of spent petrochemical sulfuric acid in the production of wet‐process phosphoric acid

The possibility of the application of spent sulfuric acid from the petrochemical industry in wet‐process phosphoric acid technology was investigated. The effect of organic impurities in sulfuric acid from benzol acidic refining on the solubility of calcium sulfate hydrates is discussed. Solubility isotherms and regression equations for CaSO₄–H₃PO₄–H₂SO₄–H₂O (pure and containing impurities) systems are presented. Phase transition temperatures between dihydrate and hemihydrate calcium sulfate were determined. The difference between pure and polluted sulfuric acid systems observed is negligible over the range of typical wet‐process phosphoric acid technology parameters. It is concluded that the application of spent sulfuric acid from benzol acidic refining does not have a negative influence on the crystallization process of dihydrate calcium sulfate and therefore can be applied in wet‐process phosphoric acid technology. Copyright © 2005 Society of Chemical Industry