A peaks-over-threshold (POT) approach is used to study trends in extreme rainfall over the Iberian Peninsula (IP) at a daily scale. Records from 52 observatories regularly distributed over Iberia with no missing data were available for the common period from 1958 to 2004. The POT approach was used because it is particularly effective at extracting information concerning true extreme events. A generalized Pareto distribution fit was made to the data involving time-dependent parameters to account for possible temporal changes in the frequency distribution. These parameters were analyzed for trends in the return-level period, of importance for engineering purposes. A time-varying threshold was defined and an automatic declustering scheme was used to select independent extreme events exceeding the threshold. The results indicate a high variability of extreme events over the coastline of the IP, greater over the Mediterranean coast than over the Atlantic coast. The calculation of the trends for the 2-yr return level yielded a large proportion of negative trends for all three seasons considered: 58% for winter, 63% for spring, and 69% for autumn. The parametric approach also revealed an increase in the area with a positive trend of the 20-yr return level relative to the 2-yr return period, especially in autumn in the east of the IP.
The order Diatrypales (Ascomycota) contains one single family, the Diatrypaceae. To obtain insight in the phylogenetic relationships within this family, the complete sequences of the ITS region (ITS1, 5.8S rRNA gene and ITS2) of 53 isolates from the five main genera in the family (Diatrype, Diatrypella, Cryptosphaeria, Eutypa and Eutypella) were determined and aligned for phylogenetic reconstruction. Sequence analysis revealed the presence of tandem repeated motifs 11 nucleotides-long, placed in homologous positions along the ITS1 region. Parsimony analysis established the existence of nine monophyletic groups and one branch with a single isolate of Eutypella quaternata. The phylogenetic relationships established by parsimony analysis did not correlate well with classical taxonomic schemes. None of the five genera included in this study was found to be monophyletic. The genera Diatrype, Eutypa and Cryptosphaeria each were divided into two groups. Isolates of Diatrype flavovirens appeared in a clade separated from the one that grouped Diatrype disciformis and the rest of Diatrype species. The Eutypa strains appeared distributed into two clades, one grouping Eutypa lata and related species (Eutypa armeniacae, Eutypa laevata, Eutypa petrakii), and anoth
[1] Heat wave event trends over the Iberian Peninsula (IP) are studied using extreme value theory, specifically the peaks-over-threshold (POT) approach. Summer (June-August) daily temperature records from 20 observatories regularly distributed over Iberia in places far from urban effects were available for the common period 1961-2010. Heat waves are defined as days occurring above the 95th percentile of the temperature distribution, considering both maximum (T max ) and minimum (T min ) temperatures. These events were identified using a "run declustering" scheme to select independent extreme events exceeding the threshold. Also, the dates of occurrence of the independent events were fitted to a Poisson process. Trends in the following parameters were studied: the scale parameter of the POT approach, the Poisson intensity, mean, return level period, and low (25th percentile) and high (75th percentile) values. The optimal trends in the Poisson intensity considering both T max and T min show a major increase in the occurrence of heat waves. Also, the rise in the return level trend was less than that in the mean of T min and T max , and the analysis of the values of T min and T max showed a greater increasing trend in the low values (25th percentile) than in the high values (75th percentile), especially for T max , leading to a decrease in the variance. Over the IP, temperature extremes are increasing but not as much as the mean because the variance is tending to decrease. This highlights the important role of variance in the evolution of extremes.
Abstract:The order Diatrypales (Ascomycota) contains one single family, the Diatrypaceae. To obtain insight in the phylogenetic relationships within this family, the complete sequences of the ITS region (ITS1, 5.8S rRNA gene and ITS2) of 53 isolates from the five main genera in the family (Diatrype, Diatrypella, Cryptosphaeria, Eutypa and Eutypella) were determined and aligned for phylogenetic reconstruction. Sequence analysis revealed the presence of tandem repeated motifs 11 nucleotides-long, placed in homologous positions along the ITS1 region. Parsimony analysis established the existence of nine monophyletic groups and one branch with a single isolate of Eutypella quaternata. The phylogenetic relationships established by parsimony analysis did not correlate well with classical taxonomic schemes. None of the five genera included in this study was found to be monophyletic. The genera Diatrype, Eutypa and Cryptosphaeria each were divided into two groups. Isolates of Diatrype flavovirens appeared in a clade separated from the one that grouped Diatrype disciformis and the rest of Diatrype species. The Eutypa strains appeared distributed into two clades, one grouping Eutypa lata and related species (Eutypa armeniacae, Eutypa laevata, Eutypa petrakii), and anothAccepted for publication September 22, 2003. 1 Corresponding author. E-mail: fernandopelaez@merck.com er with the remaining species of the genus. Eutypella (excluding Eutypella quaternaria) appeared as an unstable monophyletic group, which was lost when the sequence alignment was subjected to neighbor-joining analysis. The genus Diatrypella was not associated with any monophyletic group, suggesting that the multisporate asci character has appeared several times during the evolution of the group. Overall, our study suggests the need to revise many of the concepts usually applied to the classification of members of the family.
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