Entwicklungsszenarien einer alpinen Aue bei einem natürlichen Geschiebedefizit : die Triftaue im Oberhasli

In der zweiten Hälfte des 20. Jahrhunderts hat sich im Zuge des Gletscherrückzugs eine alpine Aue im Triftgebiet gebildet. Zu Beginn prägten dynamische Geschiebeumlagerungsprozesse die Flusslandschaft am Triftwasser und führten zu einer typischen Sukzession einer alpinen Aue. Mit dem weiteren Rückzug des Triftgletschers hat sich Anfang dieses Jahrhunderts der natürliche Triftsee gebildet, der einen Geschiebeeintrag in die darunterliegende Triftaue praktisch vollständig unterbindet. Damit wird die Geschiebedynamik im Triftwasser auf ein absolutes Minimum reduziert. Daher ist es dem Gewässer so gut wie nicht mehr möglich, seinen Verlauf im Zuge von Hochwasserereignissen zu verändern und neue morphologische Strukturen zu bilden. Aufgrund der topografischen Verhältnisse (breiter Kessel) können die natürlicherweise auftretenden Hochwasserereignisse nicht mehr genug Kraft entwickeln, um grossflächige Vegetationsbestände zu entwurzeln. Damit verbunden ist eine rasche Ausbreitung an Grünerlenbeständen, die mittelfristig die heutige Triftaue fast vollständig besiedeln werden. Im Rahmen des Triftprojekts (Vergrösserung des Triftsees mit neuem Kraftwerk auf Höhe der bestehenden Triftfassung) wurden u.a. detaillierte Studien zum Ist-Zustand sowie zur Entwicklung der Triftaue mit und ohne Projekt durchgeführt. Basierend auf diesen Untersuchungen wurden für die Realisierung des Projekts neben dem Restwasserregime zusätzlich auch Hochwasserdotierungen festgelegt

Mutations in the Catalytic Loop HRD Motif Alter the Activity and Function of Drosophila Src64

The catalytic loop HRD motif is found in most protein kinases and these amino acids are predicted to perform functions in catalysis, transition to, and stabilization of the active conformation of the kinase domain. We have identified mutations in a Drosophila src gene, src64, that alter the three HRD amino acids. We have analyzed the mutants for both biochemical activity and biological function during development. Mutation of the aspartate to asparagine eliminates biological function in cytoskeletal processes and severely reduces fertility, supporting the amino acid's critical role in enzymatic activity. The arginine to cysteine mutation has little to no effect on kinase activity or cytoskeletal reorganization, suggesting that the HRD arginine may not be critical for coordinating phosphotyrosine in the active conformation. The histidine to leucine mutant retains some kinase activity and biological function, suggesting that this amino acid may have a biochemical function in the active kinase that is independent of its side chain hydrogen bonding interactions in the active site. We also describe the phenotypic effects of other mutations in the SH2 and tyrosine kinase domains of src64, and we compare them to the phenotypic effects of the src64 null allele

Conserved Genes Act as Modifiers of Invertebrate SMN Loss of Function Defects

Spinal Muscular Atrophy (SMA) is caused by diminished function of the Survival of Motor Neuron (SMN) protein, but the molecular pathways critical for SMA pathology remain elusive. We have used genetic approaches in invertebrate models to identify conserved SMN loss of function modifier genes. Drosophila melanogaster and Caenorhabditis elegans each have a single gene encoding a protein orthologous to human SMN; diminished function of these invertebrate genes causes lethality and neuromuscular defects. To find genes that modulate SMN function defects across species, two approaches were used. First, a genome-wide RNAi screen for C. elegans SMN modifier genes was undertaken, yielding four genes. Second, we tested the conservation of modifier gene function across species; genes identified in one invertebrate model were tested for function in the other invertebrate model. Drosophila orthologs of two genes, which were identified originally in C. elegans, modified Drosophila SMN loss of function defects. C. elegans orthologs of twelve genes, which were originally identified in a previous Drosophila screen, modified C. elegans SMN loss of function defects. Bioinformatic analysis of the conserved, cross-species, modifier genes suggests that conserved cellular pathways, specifically endocytosis and mRNA regulation, act as critical genetic modifiers of SMN loss of function defects across species

Seasonal-Scale to Decadal-Scale Climatic Variability in Southwest Florida During the Middle Pliocene: Inferences from a Coralline Stable-Isotope Record

We have generated a 49‐year‐long, high‐resolution, stable isotope record from a fossil coral, Solenastrea bournoni, to evaluate regional sea surface conditions during the middle Pliocene (3.0 ± 0.5 Ma) in southwest Florida. Continuous routing of the coral slab at an interval of 0.76 mm produced ∼5 to 6 samples per year. The annual cycle is well defined in δ18O and δ13C records confirming the average yearly growth rate estimated from density banding of 4 to 5 mm/yr. High‐density bands are synchronous with the highest δ18O and δ13C values for 79% and 45% of the annual cycles recorded, respectively. The annual range in δ18O is 0.70 to 2.27‰ and in δ13C it is 0.31 to 2.21‰. Partitioning of the coral δ18O signal into sea surface temperature (SST) changes and δ18Owater changes is difficult to estimate in the ancient. However, isotopic mass‐balance calculations, using modern climate data, suggest a partitioning of the δ18O signal into 8 to 12% salinity and 92 to 88% temperature at the sea surface. If 100% of the δ18O variation is attributed to temperature, the observed mean annual range in δ18O (mean = 1.54 ± 0.37‰) corresponds to a seasonal SST range of ∼7.0 ± 1.7°C (0.22‰/1°C), which is a mean of 3.5°C less than that of the present day. Isotope data are consistent with the hypothesis that δ13C values covary with the number of sunshine hours. Annually, peak δ18O values are often observed to precede peak δ13C values by one sample (i.e., about 2 months). We infer from the isotope pattern that periods of reduced SST were followed about 2 months later by periods of increased number of sunshine hours. This seasonal pattern is similar to that of southwest Florida today. Cross‐spectral analysis of fossil coral δ18O and δ13C documents coherency peaks, above the 95% confidence interval, at annual and subdecadal frequencies (1.0, 1.6, 2.9 and 5 year). The spectral phase angle between δ18O and δ13C at the annual frequency is −60 ± 10°, at the 95% confidence interval. The temporal equivalent of this angle is approximately 2 months, which confirms visual observations of seasonality from the isotope pattern

La description d’images fixes et en mouvement par deux groupes linguistiques, anglophone et francophone, au Québec

Le présent article rapporte les résultats d’un projet de recherche entrepris dans le cadre d’une série d’études portant sur l’indexation d’images fixes ou en mouvement. L’objectif était de déterminer le niveau d’équivalence dans le choix d’expressions verbales pour représenter le contenu d’une image entre les termes d’indexation choisis par des francophones et ceux choisis par des anglophones. En comparant les résultats obtenus, nous constaterons un réel degré de similitude dans la façon de décrire les images chez les deux groupes linguistiques. De plus, ces résultats viennent appuyer l’hypothèse voulant que l’indexation d’images en français pourrait être obtenue à partir d’une indexation existante en anglais, et vice versa.The following article reports the results of a research project undertaken as part of a series of studies on the indexation of fixed and moving images. The purpose was to determine the level of equivalence used by francophones and anglophones in the choice of verbal expressions used to summarize the contents of an image. The results show that there is a high degree of similarity in the way images are described by both linguistic groups. Furthermore, these results support the hypothesis that the indexation of images in French can be accomplised using the English terms and vice versa.Este artículo presenta los resultados de un proyecto de investigación que forma parte de una serie de estudios relacionados con la indización de imágenes fijas o en movimiento. El objetivo fue determinar el nivel de equivalencia existente dentro de la selección de expresiones verbales para representar el contenido de una imagen entre los términos de indización elegidos por los francoparlantes y por los angloparlantes. Al comparar los resultados obtenidos, constatamos que existe una real similitud en la manera de describir las imágenes en ambos grupos lingüísticos. Además, estos resultados apoyan la hipótesis que afirma que la indización de imágenes en francés podría obtenerse a partir de una indización existente en inglés, y viceversa

Soil-plant-atmosphere transfer of organic and metal(oid) pollutants in an industrial and urban area

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: field monitoring and modelling

International audienceCurrent ¹³⁷Cs levels in French forests are mainly due to global fallouts (GF) from nuclear weapon tests and deposition from Chernobyl accident. Since Fukushima accident, there has been an increasing interest in the behavior of this persistent radionuclide in the soil-tree system at short and mid-term after its deposit (95%) with a weak contribution of the organic layers (<1%).Stand-averaged ¹³⁷Cs activity concentrations in tree organs vary by more than an order of magnitude in the 3 stands, from typically ~0.1 to ~4 Bq/kg dw. The pattern is similar to that observed at short-term after Chernobyl and Fukushima accidents: roots ≥ leaves/needles = twigs ≥ bark ≥ branches = stemwood. In HET and CPS, ¹³⁷Cs and ¹³³Cs concentrations were linearly related (r≥0.9; p<0.001), suggesting a reached equilibrium. Whatever the isotope, the variability observed between individual trees is not correlated to tree characteristics (tree age, DBH or height) and remains under investigation at this stage.Normalized ¹³⁷Cs activity concentrations in stemwood (NC, m²/kg) of beech trees strongly vary between sites, from ~0.7 10^-4 m²/kg at HET site to ~5.1 10^-4 m²/kg at PS site. Such a variability could not be explained by differences in the ¹³⁷Cs soil exchangeable fraction. NC in stemwood of oaks and Scots pines are lower than those of companying beeches (1.1 10^-4 and 0.8 10^-4 m²/kg, respectively). Our results are 1 order of magnitude lower than those observed on the mid-term after Chernobyl, likely indicating a long-term decrease of ¹³⁷Cs bioavailability in soil.Investigations on potassium behavior, estimation of BGC fluxes for ¹³⁷Cs, ¹³³Cs and K, as well as on the selectivity coefficients for transfer processes, are under progress

Soil-plant-atmosphere transfer of organic and metal(oid) pollutants in an industrial and urban area

International audienc