Urban land use types contribute to grassland conservation: The example of Berlin

Urbanisation is an important driver of biodiversity loss, also contributing to habitat loss and fragmentation of grasslands at the urban-rural interface. While urban green spaces are known to include many grassland habitats, it is uncertain to what extent urban land use types harbour grasslands of special conservation interest and whether patch characteristics and connectivity of these differ from grasslands on agricultural land. By relating the city-wide biotope mapping to the land use mapping of Berlin, Germany, we assessed (1) to which specific urban land use types the major grassland biotope types belong, (2) differences in patch characteristics and connectivity, and (3) the conservation value of grassland patches at a typological level by means of their legal protection status. Grasslands cover 5% of Berlin's surface, and 43% of that area is assigned to legally protected grassland types. The majority of legally protected grassland (71%) lies on urban land opposed to 29% on agricultural land. Airports and historic parks, which only cover 2% of land in Berlin, contain one-third of all protected dry grasslands. Wet grassland is more confined to agricultural land. In airports and agricultural areas, grassland patches are larger but of a more complex shape than those in historic parks. In airports, grassland patches show greater connectivity as they are situated in grassland-dominated surroundings. Grassland in historic parks appears to be more vulnerable due to smaller patch sizes and higher fragmentation. The example of Berlin demonstrates that the urban green infrastructure can clearly contribute to grassland conservation and may thus partially compensate for the decline of traditional grasslands in cultural landscapes. It will be important to involve residents and landowners in urban grassland conservation and management because most grassland of special conservation interest (57%) was found outside of conservation areas.     

Ultra‐thin sectioning and grinding of epoxy plastinated tissue

With classical sheet plastination techniques such as E12, the level and thickness of the freeze‐cut sections decide on what is visible in the final sheet plastinated sections. However, there are other plastination techniques available where we can look for specific anatomical structures through the thickness of the tissue. These techniques include sectioning and grinding of plastinated tissue blocks or thick slices. The ultra‐thin E12 technique, unlike the classic E12 technique, starts with the plastination of a large tissue block. High temperatures (30–60°C) facilitate the vacuum‐forced impregnation by decreasing the viscosity of the E12 and increasing the vapour pressure of the intermediary solvent. By sectioning the cured tissue block with a diamond band saw plastinated sections with a thickness of <300 μm can be obtained. The thickness of plastinated sections can be further reduced by grinding. Resulting sections of <100 µm are suitable for histological staining and microscopic studies. Anatomical structures of interest in thick plastinate slices can be followed by variable manual grinding in a method referred to as Tissue Tracing Technique (TTT). In addition, the tissue thickness can be adapted to the transparency or darkness of tissue types in different regions of the same plastinated section. The aim of this study was to evaluate the advantages of techniques based on sectioning and grinding of plastinated tissue (E12 ultra‐thin and TTT) compared to conventional sheet‐forming techniques (E12).     

III. Buchbesprechungen

Ohne Zusammenfassung     

III. Buchbesprechungen

Ohne Zusammenfassung     

Maximal lactate concentrations in horses after exercise of different duration and intensity

Lactate kinetics in whole blood of horses was investigated after exercise of differing velocities and duration. The following categories of exercise were used: A: <11 m/second and >180 seconds (n=35), B: >11 m/second and <180 seconds (n=17) and C: <11 m/second and <180 s (n=10). The mean peak lactate concentration determined in horses in category A was 4.49 ± 2.21 mmol/1, in B, 16.32 ± 4.81 mmoVl and in C, 4.58 ± 1.59 mmol/l. While the maximum lactate concentrations in categories A and C were always found immediately after the exercise, the peaks in category B were measured between the first and tenth minute after exercise. Mean lactate concentrations measured at 2-minute intervals after bouts of category-B exercise tended to stabilize 3 to 10 minutes after exercise; however, mean lactate concentrations measured during the intervals before and after the peak value differed significantly. The lactate concentration returned to pre-exercise levels within 20 minutes after exercise bouts of category C, but remained above pre-exercise levels up to 60 minutes after bouts of category-A and -B exercise. It was concluded that, for an evaluation of lactate data after intensive anaerobic exercise, sequential blood sampling at 2-minute intervals for a period of up to 12 minutes after exercise is necessary. Less frequent sampling may be a reason for the often described irreproducibility of lactate concentrations in horses. After aerobic or mild anaerobic exercise, one sample is sufficient, but it has to be taken as soon as possible after exercise.     

III. Buchbesprechungen

Ohne Zusammenfassung     

Characterization of wood-based multi-material systems under dynamic impact stress

ABSTRACT

Due to its naturally grown properties, wood has played a rather subordinate role as a material for technical applications up to now. In this paper, multi-material systems based on veneers of beech (Fagus sylvatica) with different reinforcing variants were investigated. In addition to the influence of different adhesive systems (urea formaldehyde and polyurethane), the effect of reinforcing by aramid fiber fabric and stainless steel foil in different climates was examined. At the center of the investigations were dynamically sudden loads, in the form of impact bending and dart drop tests (penetration and impact mode). It has been shown that the use of the reinforcing materials leads to a significant improvement in material properties. The penetration energy of the composites reinforced with the aramid fiber fabric could be increased by 43%. The maximum force in the dart drop test (impact mode) could be increased by 29% with the stainless steel foil, the damping decreased by 48%. The aramid fiber reinforcement achieved an increase in impact resistance by 27% in impact bending test, the steel reinforced achieved an increase of 39%. A clear dependency on both, the climate and the adhesive within the composite, could be demonstrated.     

Age determination of large live trees with inner cavities: radiocarbon dating of Platland tree,a giant African baobab

• Introduction   

For large trees without a continuous sequence of growth rings in their trunk, such as the African baobab (Adansonia digitata L.), the only accurate method for age determination is radiocarbon dating. As of today, this method was limited to dating samples collected from the remains of dead specimens.