Scientific results of the Bryotrop expedition to Zaire and Rwanda : 7., life strategies of epiphytic bryophytes from tropical lowland and montane forests, ericaceous woodlands and the Dendrosenecio subpáramo of the eastern Congo basin and the adjacent mountains (Parc National de Kahuzi-Biega/Zaire, Forêt de Nyungwe/Rwanda)

Life strategies of epiphytic bryophytes are studied along an altitudinal gradient from the eastern Congo basin (tropical lowland zone) to the mountains of the East-African graben (tropical subalpine/alpine Zone; BRYOTROP III-transect). Three strategies, Colonists, Perennial shuttle species and Perennial stayers can be observed, which are further subdivided according to their reproduction tactic (high sexual reproductive effort, high asexual reproductive effort, moderately or low sexual and asexual reproductive effort). Of these, only taxa with a long life span (perennials) are of importance, indicating the unchanging and constant ecological conditions and long-lasting microsites, provided by the epiphytic habitats. The basis for the life strategy pattern analysis along the altitudinal gradient were plant sociological investigations and the determination of the mean percentage cover values for the different life strategy categories. By this, the distribution and occurrence of the different strategies within the communities and the altitudinal zones can be shown

Bewertung und Entwicklung künstlicher Stehgewässer im Biosphärenreservat Pfälzerwald

The survival of the approximately 1,000 artificial ponds in the Pfälzerwald (Palatinate Forest) biosphere reserve is endangered as they continue to be abandoned, but a large number of them have conservation and historical value. An overall management concept is needed as the high costs for restoration and the requirements of the EU Water Framework Directive regarding river continuity will make it impossible to maintain all of the ponds. Most of the ponds are migration barriers for fish and aquatic invertebrates. The assessment methods presented here are based on readily available data for the evaluation of the ecological and cultural-historical importance of the ponds, their implications within the landscape, and their (often negative) impact on stream ecology. The assessment of the condition of the ponds’ manmade structures leads to conclusions about the urgency for action. The assessment classes are linked with recommendations for action. In the synopsis of all assessments, management concepts emerge for the individual ponds, and priority lists of ponds can be generated that point out where actions are preferential.Aufgrund zunehmender Nutzungsaufgabe an den etwa 1.000 künstlichen Stehgewässern im Biosphärenreservat Pfälzerwald und ihrer gleichzeitig oft hohen naturschutzfachlichen bzw. kulturhistorischen Bedeutung ist ein Managementkonzept notwendig geworden. Dem Erhalt der Anlagen stehen hohe Sanierungskosten sowie die Anforderungen der EU-Wasserrahmenrichtlinie, für eine biologische Durchgängigkeit der Fließgewässer zu sorgen, entgegen. Die meisten Anlagen stellen nämlich unüberwindliche Wanderbarrieren dar. Die vorgestellten Bewertungsverfahren, basierend auf einfach zu erhebenden Merkmalen, beurteilen die ökologische und die kulturhistorische Bedeutung der Anlagen, die Bedeutung für das Landschaftsbild sowie ihre (negativen) Auswirkungen auf das Fließgewässersystem. Die Bewertung des baulichen Zustands ergibt Aussagen über die Dringlichkeit des Handelns. Die einzelnen Bewertungsklassen sind mit Handlungsempfehlungen verknüpft. In der Zusammenschau der einzelnen Empfehlungen leiten sich Maßnahmen für die einzelnen Gewässer ab sowie Priorisierungen von Teichen, an denen vorrangig Handlungen erfolgen sollen

Integration of Pulsed Electric Fields in the Biorefinery Concept to Extract Microalgae Components of Interest for Food Industry

The high cultivation costs for microalgae and the complex and costly downstream processing make the price per ton of raw materials from microalgae biomass, such as biofuel, uneconomic. To overcome this detriment, it is suggested to use the residual biomass for biofuel production after obtaining high- and middle-value products. Microalgae are an attractive food source, since they are rich in proteins, peptides, carbohydrates, lipids, and other essential nutrients with protective and detoxifying roles (vitamins, minerals, pigments). A major problem is that these valuable components cannot be accessed without prior and adequate cell disruption. This chapter discusses a new strategy to integrate PEF treatment into biorefinery concept by implementation of an incubation step which facilitates the release of intracellular components after PEF treatment. Based on the results obtained from the microalgae Chlorella vulgaris and the cyanobacteria Arthrospira platensis, the dependence of various influencing factors such as temperature, pH value, and biomass concentration on protein release during the incubation step is shown. Finally, the efficiency of this approach is discussed

The role of first- and second-order stimulus features for human overt attention

When processing complex visual input, human observers sequentially allocate their attention to different subsets of the stimulus. What are the mechanisms and strategies that guide this selection process? We investigated the influence of various stimulus features on human overt attention—that is, attention related to shifts of gaze with natural color images and modified versions thereof. Our experimental modifications, systematic changes of hue across the entire image, influenced only the global appearance of the stimuli, leaving the local features under investigation unaffected. We demonstrated that these modifications consistently reduce the subjective interpretation of a stimulus as "natural” across observers. By analyzing fixations, we found that first-order features, such as luminance contrast, saturation, and color contrast along either of the cardinal axes, correlated to overt attention in the modified images. In contrast, no such correlation was found in unmodified outdoor images. Second-order luminance contrast ("texture contrast”) correlated to overt attention in all conditions. However, although none of the second-order color contrasts were correlated to overt attention in unmodified images, one of the second-order color contrasts did exhibit a significant correlation in the modified images. These findings imply, on the one hand, that higher-order bottom-up effects—namely, those of second-order luminance contrast—may partially account for human overt attention. On the other hand, these results also demonstrate that global image properties, which correlate to the subjective impression of a scene being "natural,” affect the guidance of human overt attentio

Nanosecond pulsed electric fields modulate the expression of the astaxanthin biosynthesis genes psy, crtR-b and bkt 1 in Haematococcus pluvialis

Nanosecond pulsed electric fields (nsPEFs) have been extensively studied with respect to cellular responses. Whether nsPEFs can regulate gene expression and to modulate the synthesis of valuable compounds, has so far been only tested in the context of apoptosis in cancer cells. We used the unicellular algae Haematococcus pluvialis as system to test, whether nsPEFs could alter gene expression and to promote the biosynthesis of astaxanthin. We find that nsPEFs induce a mild, but significant increase of mortality up to about 20%, accompanied by a moderate increase of astaxanthin accumulation. Steady-state transcript levels of three key genes psy, crtR-b and bkt 1 were seen to increase with a maximum at 3 d after PEF treatment at 50 ns. Pulsing at 25 ns reduce the transcripts of psy, crtR-b from around day 2 after the pulse, while those of bkt 1 remain unchanged. By blocking the membrane-located NADPH oxidase RboH, diphenylene iodonium by itself increased both, the levels of astaxanthin and transcripts of all three biosynthetic genes, and this increase was added up to that produced by nsPEFs. Artificial calcium influx by an ionophore did not induce major changes in the accumulation of astaxanthin, nor in the transcript levels, but amplified the response of crtR-b to nsPEFs at 25 ns, while decreased in 50 ns treatment. When Ca2+ influx was inhibited by GdCl3, the transcript of psy and bkt 1 were decreased for both 25 ns and 50 ns treatments, while crtR-b exhibited an obvious increase for the 25 ns treatment. We interpret these data in a working model, where nsPEFs permeabilise plasma and chloroplast membrane depending on pulse duration leading to a differential release of plastid retrograde signaling to the nucleus

Dimethyl 2,6,8-trimethyl-1,2-dihydroquinoline-2,4-dicarboxylate

The title compound, C16H19NO4, the hydrogenated ring adopts a twisted conformation. In the crystal, inter­molecular C—H⋯O hydrogen bonds link the mol­ecules into centrosymmetric R 2 2(10) dimers. These dimers are further connected via inter­molecular N—H⋯O hydrogen bonds, forming infinite double chains along [001]

structural characterization of Pd(II) complexes and their catalytic properties

The exclusive formation of the 1,5-cycloaddition product between azides and alkynes is taken advantage of in generating the first examples of abnormal carbenes from these precursors. This new route provides unprecedented post- functionalization possibilities for such abnormal carbenes