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Am 7. Dezember 2002 verstarb Walter Klein. Er war begeisterter Amateurfunker und Segelflieger, und er engagierte sich seit den siebziger Jahren zunehmend intensiver in der Botanik und dem Naturschutz. Die intensive Beschäftigung mit der Flora begann 1978, als für das Projekt der Kartierung der Flora Mitteleuropas Mitarbeiter gesucht wurden. Walter Klein und seine Ehefrau Elisabeth übernahmen vier Kartierungsgebiete in der östlichen Wetterau. Auf ungezählten Exkursionen während sieben Jahren wurde die über 500 Quadratkilometer große Fläche eingehend erforscht. Walter Klein trat bald in die 1979 gegründete Botanische Vereinigung für Naturschutz in Hessen (BVNH) ein, übernahm 1985 die Funktion des so genannten Kreisvertrauensmannes und wurde wenig später Mitglied im Naturschutzbeirat des Wetteraukreises.
Die Grün-Esche ist auf der Mainspitze bei Ginsheim-Gustavsburg eingebürgert und besiedelt ein Areal von etwa 4 ha Fläche. Die Population besteht bereits länger, da Pflanzen aller Altersklassen vorhanden sind. Neben alten, teils schon absterbenden Altbäumen wächst zahlreich Jungwuchs. Die Standorte sind anthropogen gestört: die durch Abgrabungen und Aufschüttungen stark veränderte Mainaue mit Resten des Auenwaldes, die mit großen Blöcken befestigte Mainuferböschung sowie der Geländestreifen neben und unter einer Eisenbahnbrücke. Die einheimische Fraxinus excelsior spart das lokale Areal der nordamerikanischen Art weitgehend aus, ist aber in der Umgebung reichlich vorhanden. Die taxonomische Einstufung der Grün-Esche wird überprüft. Grün- und Rot-Esche (F. pennsylvanica s. str.) verhalten sich in Nordamerika wie geographische Rassen, weshalb für sie der Unterartrang als angemessen angesehen wird. Dies macht eine Neukombination notwendig: F. pennsylvanica subsp. novae-angliae (Wesmael) Buttler, combinatio nova.
Die Entwicklung von zwei Zwerggras-Populationen in Südhessen wird dokumentiert. Im Naturschutzgebiet Schwanheimer Düne, wo ein kleines Vorkommen auf einer Baumscheibe bestand, ist die Art wahrscheinlich verschwunden. Als Ursachen kommen Bodenverfestigung und Zuwachsen infolge Brache sowie Schafbeweidung in Frage. Bei Dreieich-Sprendlingen sind die Bestände, die 2004 auf 7000 m2 mehrere hunderttausend Pflanzen umfassten und in früheren Jahren noch reicher waren, 2005 auf kleine Reste geschrumpft. Ursache ist die Nutzungsänderung von Gärtnereinutzung zu großflächigem Ackerbau (Mais- und Getreideanbau). Hier ist das Verschwinden der Art absehbar. Nur ein Restbestand ist in einem Hausgarten erhalten geblieben.
Cognitive flexibility, the ability to flexibly switch between tasks, is a core dimension of executive functions (EFs) allowing to control actions and to adapt flexibly to changing environments. It supports the management of multiple tasks, the development of novel, adaptive behavior and is associated with various life outcomes. Cognitive flexibility develops rapidly in preschool and continuously increases well into adolescence, mirroring the growth of neural networks involving the prefrontal cortex. Over the past decade, there has been increasing interest in interventions designed to improve cognitive flexibility in children in order to support the many developmental outcomes associated with cognitive flexibility. This article provides a brief review of the development and plasticity of cognitive flexibility across early and middle childhood (i.e., from preschool to elementary school age). Focusing on interventions designed to improve cognitive flexibility in typically developing children, we report evidence for significant training and transfer effects while acknowledging that current findings on transfer are heterogeneous. Finally, we introduce metacognitive training as a promising new approach to promote cognitive flexibility and to support transfer of training.
The molecule of the title compound, C14H16N2O2, is located on a crystallographic twofold rotation axis. The central O-C-C-O bridge adopts a gauche conformation. One of the amine H atoms is disordered over two equally occupied positions. The crystal structure is stabilized by N-H...O and N-H...N hydrogen bonds. Key indicators: single-crystal X-ray study; T = 173 K; mean σ(C–C) = 0.002 Å; disorder in main residue; R factor = 0.049; wR factor = 0.119; data-to-parameter ratio = 17.9.
Aboriginal migration from South East Asia is the beginning of Australian economic history. Prehistorians have tended to focus on means to sea travel rather than opportunity and motive to migrate. American and Australian measures of sea depth contours throw new light on possible migration paths and the conditions that might have prompted Aboriginal ancestors to move through island SE Asia to Australia. Interpretation of the data depends on a reconsideration of palaeodemography and the introduction of some economic and historical analysis. Several scenarios suggest possible conditions influencing trends and fluctuations in Aboriginal migration over the past 60,000 years.
A consistent muscle activation strategy underlies crawling and swimming in Caenorhabditis elegans
(2014)
Although undulatory swimming is observed in many organisms, the neuromuscular basis for undulatory movement patterns is not well understood. To better understand the basis for the generation of these movement patterns, we studied muscle activity in the nematode Caenorhabditis elegans. Caenorhabditis elegans exhibits a range of locomotion patterns: in low viscosity fluids the undulation has a wavelength longer than the body and propagates rapidly, while in high viscosity fluids or on agar media the undulatory waves are shorter and slower. Theoretical treatment of observed behaviour has suggested a large change in force–posture relationships at different viscosities, but analysis of bend propagation suggests that short-range proprioceptive feedback is used to control and generate body bends. How muscles could be activated in a way consistent with both these results is unclear. We therefore combined automated worm tracking with calcium imaging to determine muscle activation strategy in a variety of external substrates. Remarkably, we observed that across locomotion patterns spanning a threefold change in wavelength, peak muscle activation occurs approximately 45° (1/8th of a cycle) ahead of peak midline curvature. Although the location of peak force is predicted to vary widely, the activation pattern is consistent with required force in a model incorporating putative length- and velocity-dependence of muscle strength. Furthermore, a linear combination of local curvature and velocity can match the pattern of activation. This suggests that proprioception can enable the worm to swim effectively while working within the limitations of muscle biomechanics and neural control.
The Peak Range (22˚ 28’ S; 147˚ 53’ E) is an archipelago of rocky peaks set in grassy basalt rolling-plains, east of Clermont in central Queensland. This report describes the flora and vegetation based on surveys of 26 peaks. The survey recorded all plant species encountered on traverses of distinct habitat zones, which included the ‘matrix’ adjacent to each peak. The method involved effort comparable to a general flora survey but provided sufficient information to also describe floristic association among peaks, broad habitat types, and contrast vegetation on the peaks with the surrounding landscape matrix. The flora of the Peak Range includes at least 507 native vascular plant species, representing 84 plant families. Exotic species are relatively few, with 36 species recorded, but can be quite prominent in some situations. The most abundant exotic plants are the grass Melinis repens and the forb Bidens bipinnata. Plant distribution patterns among peaks suggest three primary groups related to position within the range and geology. The Peak Range makes a substantial contribution to the botanical diversity of its region and harbours several endemic plants among a flora clearly distinct from that of the surrounding terrain. The distinctiveness of the range’s flora is due to two habitat components: dry rainforest patches reliant upon fire protection afforded by cliffs and scree, and; rocky summits and hillsides supporting xeric shrublands. Plants endemic to the Peak Range are mainly associated with the latter of these habitats.
Twenty-eight species of epiphyllous liverworts were identified from twenty-five sites in Kowloon Peninsula, Hong Kong. Twenty-four of these species are new records to Hong Kong, while four of them are new epiphyllous records to the Chinese mainland. The majority of the sites are located between 30-200 m above sea level, representing the lowest altitude of epiphyllous liverworts found in the Chinese mainland. Characteristics of the host plants bearing epiphyllous liverworts are briefly discussed. The following new combination is proposed: Cololejeunea pseudolatilobula (Chen & Wu) But & Gao comb. nov. (Pedinolejeunea pseudolatilobula Chen & Wu).