How does human exploitation affect impala populations in protected and partially protected areas? - A case study from the Serengeti Ecosystem, Tanzania

Human exploitation can have severe conservation implications for wildlife populations. In the Serengeti ecosystem, Tanzania, illegal hunting is a serious concern for wildlife management, and in this study we investigated if density, demography and behaviour can be used as indicators of human exploitation. We used impala (Aepycerus melampus) as a model species to study human exploitation inside and outside a strictly protected area. Over a six month period, a total of 2050 km of transects were driven in the different protected areas (National Park, Game Reserve, Open Area). Densities were estimated by using distance sampling and the partially protected areas were found to have significantly lower densities (4.3 ind/km²) than the National Park (15.3 ind/km²). A variation in density between different sections within the National Park was also found. However, we found no differences in group sizes. Moreover, the sex-ratio was more skewed towards females in the partially protected areas and in sections within the National Park close to villages. In addition, impalas showed higher alertness levels, and longer flight initiation distance to an approaching human in the partially protected areas compared to the National Park. The present harvest levels by illegal hunting in the study area are most likely the cause of the observed differences. Our results suggest that density, demography and behaviour can be used as indicators of human exploitation, but that this probably varies according to local hunting pressure. Furthermore, it could be expected that the results obtained in this study might reflect the state of other ungulates in the area, which raises concern whether management objectives for the buffer zones of Serengeti National Park are met.     

Microfossils in Wisconsinan Loess and Till from Western Illinois and Eastern Iowa

Wisconsinan loess from Illinois and Iowa contains a varied assemblage of microfossils including radiolaria, foraminifera, sponge spicules, and opal phytoliths. The foraminifera and radiolaria are derived from Cretaceous rocks occurring on the northern Great Plains. The sponge spicules are from fresh-water sponges living during the epoch of loess deposition. The phytoliths were produced by vegetation growing during deposition. These microfossils are valuable in determining loess and till provenance and in paleoecological reconstruction.     

High-throughput quantitation of peroxyl radical scavenging capacity in bulk oils

Autoxidation of methyl linoleate (8:2 mixture with decane, 37 degrees C) was induced by 2,2'-azobis(2,4-dimethylvaleronitrile) (AMVN, 17.7 mM) and the kinetics of oxygen consumption monitored using a 96-well microplate coated with an oxygen-sensitive fluorescence probe, a ruthenium dye, embedded in a silicone matrix at the bottom of the microplate. The probe does not participate in the reaction; instead, its fluorescence intensity is inversely proportional to the solution oxygen concentration as it changes during oxidation. In the absence of antioxidants, the oxidation rate has a linear relationship with the square root of the initiator concentrations. This is in agreement with theoretical autoxidation kinetics equations. In the presence of tocopherol-type antioxidants, a sharp lag phase appears. The quantitation of the antioxidant capacity is achieved using the area under the curve (AUC) approach. The assay has a 2 h running time, a linearity range from 1.56 to 18.7 microM (Trolox), and a limit of quantitation at 2.7 microM Trolox equivalency. The peroxyl radical scavenging capacities of several cold-pressed and organically grown plant seed oils were quantified along with the tocopherol concentrations of the oils. Tocopherols contribute only a fraction of the peroxyl radical scavenging capacity of the oils, and there is poor correlation between total tocopherol concentrations and radical scavenging capacity, suggesting that the antioxidant capacity of oils is due not only to tocopherols but also to other lipid-soluble antioxidants.     

Can a post-harvest ripening treatment extend the longevity of Rhododendron L. seeds?

Pre-dehiscent capsules were collected from two Rhododendron griersonianum (Balf.f. & Forrest) trees and either immediately dried in a dry-room (15% relative humidity, 15 °C) or placed in a high humidity room (80% relative humidity, 15 °C) for 30, 60, or 90 d. Further capsules were also collected from the trees at 30 and 60 d, but seeds had been dispersed by 90 d. Seed ageing experiments (60% relative humidity, 45 °C) carried out on these seed-lots and on seeds from a further 10 Rhododendron (L.) species confirmed that short seed lifespans is a trait of the genus, with a mean P₅₀ value of ca. 20 d for this storage environment.     

Comparative genomics of the eukaryotes

A comparative analysis of the genomes of Drosophila melanogaster, Caenorhabditis elegans, and Saccharomyces cerevisiae-and the proteins they are predicted to encode-was undertaken in the context of cellular, developmental, and evolutionary processes. The nonredundant protein sets of flies and worms are similar in size and are only twice that of yeast, but different gene families are expanded in each genome, and the multidomain proteins and signaling pathways of the fly and worm are far more complex than those of yeast. The fly has orthologs to 177 of the 289 human disease genes examined and provides the foundation for rapid analysis of some of the basic processes involved in human disease.