The present paper presents and discusses the relationships between live Fuel Moisture Content (FMC) measurements and fire occurrence (number of fires and burned area) in a Mediterranean area of central Spain. Grasslands and four shrub species (Cistus ladanifer L., Rosmarinus officinalis L., Erica australis L. and Phillyrea angustifolia L.) were sampled in the field from the spring to the summer season over a 9-year period. Higher seasonal FMC variability was found for the herbaceous species than for shrubs, as grasslands have very low values in summertime. Moisture variations of grasslands were found to be good predictors of number of fires and total burned surface, while moisture variation of two shrubs (C. ladanifer L. and R. officinalis L.) was more sensitive to both the total burned area and the occurrence of large fires. All these species showed significant differences between the FMC of high and low occurrence periods. Three different logistic regression models were built for the 202 periods of analysis: one to predict periods with more and less than seven fires, another to predict periods with and without large fires (>500 ha), and the third to predict periods with more and less than 200 ha burned. The results showed accuracy in predicting periods with a high number of fires (94%), and extensive burned area (85%), with less accuracy in estimating periods with large fires (58%). Finally, empirical functions based on logistic regression analysis were successfully related to fire ignition or potential burned area from FMC data. These models should be useful to integrate FMC measurements with other variables of fire danger (ignition causes, for instance), to provide a more comprehensive assessment of fire danger conditions.

New total syntheses of didemnin A and of dehydrodidemnin B are described. The latter didemnin has the highest antiproliferative activity of all members of this family of macrocyclic depsipeptides. It was produced on coupling the side chain Pyr-Pro-OH to didemnin A, which was itself synthesized by two novel routes. One of these was based on the elaboration of a linear heptadepsipeptide incorporating the first amino acid of the didemnin side chain, (R)-N(Me)-Leu. Deprotection of the amino and carboxyl terminii of this linear precursor followed by macrocyclization gave a protected derivative of didemnin A. The second route involved synthesis of the Boc-protected didemnin macrocycle from a linear hexadepsipeptide lacking (R)-N(Me)-Leu. Removal of the Boc group from the macrocycle followed by its coupling with Boc-(R)-N(Me)-Leu-OH then gave Boc-didemnin A. The overall yield was much higher for the second strategy (27% compared to 4% for the first synthesis), but both allowed synthetic didemnin A, identical with a natural sample, to be prepared. Extensive use was made of phosphonium and uronium salt-based coupling reagents, such as BOP, PyBrOP, PyAOP, HBTU, and HATU for the formation of both the secondary and tertiary amide bonds present in these complex depsipeptides.

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The soils of Puchuncaví and Quintero, in the coastal area of central Chile, have been exposed to atmospheric deposition of sulfur dioxide (SO 2 ) and metal-rich particles from the Ventanas Industrial Complex. The objective of this study was to determine, using geostatistical tools, the spatial distribution of copper and pH in these soils. Using Universal Kriging tool for geostatistical interpolation, we generated maps of continuous distribution of Cu and pH in the soils. The distribution of these variables was related to the distance from the industrial complex and to the direction of the winds. The concentrations of Cu and acidity were higher in the surroundings to the industrial complex and in the direction of the dominant winds. Although the distributions of both variables were similar, there was no correlation between the distribution of Cu and pH, which could be due to the distinct aerial dispersion dynamics of the compounds, which causes a divergence in their deposition on the soil. Specifically, this could be due to the fact that SO 2 is smaller than the particulate matter that contains copper, so that it is capable of being dispersed over greater distances without being deposited on the soil.

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Three different synthetic routes to the uncommon a-amino acid D-alloisoleucine were studied. The first was based on the stereospecific inversion of configuration of the C-2 stereogenic carbon of Lisoleucine. The second involved acetylation of L-isoleucine with epimerisation at the C-2 carbon, giving a mixture of L-isoleucine and D-alloisoleucine, which was resolved enzymically with hog kidney acylase. In a new approach, an epimeric mixture of L-isoleucine and D-alloisoleucine was synthesized from (S) -2-methylbutan-1 -01 and was again resolved enzymically. The D-alloisoleucine produced in these syntheses was subsequently transformed into the y-amino acid isostatine.