STUDIES ON PLANT BILE PIGMENTS-6. PHOTOCHEMICALLY ASSISTED REACTION OF A-DIHYDROBILINDIONE WITH NUCLEOPHILES AS A MODEL FOR PHYTOCHROME INTERCONVERSION

From the A-dihydrobilindione 3. the pyridinium derivatives 6a,b and analogues thereof have been obtained by a formal nucleophilic substitution. The reaction is rationalized as a photochemically assisted oxidation of 3 with a subsequent regioselective addition of pyridine at C-5. By thermolysis. 6a.b yields back the parent bilin 3, together with an oxidation product. The significance of the reaction with respect to the phytochrome interconversion is discussed

Lost in bureaucracy : the experience of Rwandan refugee women in Cape Town

Bibliography: leaves 72-78

Zwischen Marginalität und Allmachtsfantasien. Neuere Publikationen zum Pädagogikunterricht in der gymnasialen Oberstufe

Nach kurzen Hinweisen zur Institutionalisierung des Faches bzw. zur prekären Situation der Fachdidaktik Pädagogikunterricht und einem kurzen Überblick über die aktuelle Ausdifferenzierung des Diskursfeldes werden für den aktuellen Stand der fachdidaktischen Diskussion charakteristische Arbeiten von K. Beyer, E. Wortmann, E. Stiller und G. Koumides vorgestellt. Dabei werden Subjektorientierung und Handlungspropädeutik als der - trotz unterschiedlicher Akzentuierungen - gemeinsame Bezugspunkt dieser Arbeiten herausgestellt und das Fehlen einer empirischen Bedingungsanalyse des Faches sowie das Desinteresse an bildungssoziologischen Fragestellungen moniert. (DIPF/Orig.)Following a brief sketch of the institutionalization of the school subject pedagogics and of the precarious situation of the didactics of pedagogical instruction as well as a short survey on the recent differentiation of the field of discourse, the authors report on the studies by K. BEYER, E. WORTMANN, E. STILLER, and G. KOUMIDES, which are characteristic of the recent discussion on pedagogical didactics. Subject orientation and practice-related preparatory courses are revealed as a point of reference common to all of these studies, despite their different accentuations. However, the authors criticize the lack of an empirical analysis of the conditions of the subject pedagogics as well as the lack of interest in issues relating to educational sociology. (DIPF/Orig.

Use of TanDEM-X and Sentinel Products to Derive Gully Activity Maps in Kunene Region (Namibia) Based on Automatic Iterative Random Forest Approach

Gullies are landforms with specific patterns of shape, topography, hydrology, vegetation, and soil characteristics. Remote sensing products (TanDEM-X, Sentinel-1, and Sentinel-2) serve as inputs into an iterative algorithm, initialized using a micromapping simulation as training data, to map gullies in the northwestern of Namibia. A Random Forest Classifier examines pixels with similar characteristics in a pool of unlabeled data, and gully objects are detected where high densities of gully pixels are enclosed by an alpha shape. Gully objects are used in subsequent iterations following a mechanism where the algorithm uses the most reliable pixels as gully training samples. The gully class continuously grows until an optimal scenario in terms of accuracy is achieved. Results are benchmarked with manually tagged gullies (initial gully labeled area <0.3% of the total study area) in two different watersheds (408 and 302 km2, respectively) yielding total accuracies of >98%, with 60% in the gully class, Cohen Kappa >0.5, Matthews Correlation Coefficient >0.5, and receiver operating characteristic Area Under the Curve >0.89. Hence, our method outlines gullies keeping low false-positive rates while the classification quality has a good balance for the two classes (gully/no gully). Results show the most significant gully descriptors as the high temporal radar signal coherence (22.4%) and the low temporal variability in Normalized Difference Vegetation Index (21.8%). This research builds on previous studies to face the challenge of identifying and outlining gully-affected areas with a shortage of training data using global datasets, which are then transferable to other large (semi-) arid regions.This research is part of the DEM_HYDR2024 project sup ported by TanDEM-X Science Team, therefore the authors would like to express thanks to the Deutsches Zentrum für Luft und Raumfahrt (DLR) as the donor for the used TanDEM-X datasets. They acknowledge the financial support provided by the Namibia University of Science and Technology (NUST) within the IRPC research funding programme and to ILMI for the sponsorship of field trips to identify suitable study areas. Finally, they would like to express gratitude toward Heidelberg University and the Kurt-Hiehle-Foundation for facilitating the suitable work conditions during this research