Farmers' assessment of the social and ecological values of land uses in central highland Ethiopia

Often in land use evaluations, especially those in developing countries, only the financial aspect receives serious attention, while the social and ecological values are overlooked. This study compared the social and ecological values of four land use types (small-scale woodlot [SSW], boundary tree and shrub planting [BTP], homestead tree and shrub growing [HTG] and cereal farming [CF]) by a criteria-based scoring approach using a bao game. The impacts of local wealth status and proximity to a forest on the value the community renders to the land use types were also assessed. The value comparison, assessed by relative scoring, was accompanied by farmer’s explanations to reveal the existing local knowledge about land use values. It was found that HTG ≥ SSW > BTP > CF for both social and ecological values. Though this trend applies for the medium and rich households, the poor ones chose SSW as the most valuable. With increasing distance from a forest, the social and ecological values of land uses increased. The accompanying scoring justifications indicated the existence of in-depth ecological knowledge, which conform to contemporary scientific reports. Generally, this study showed that social and ecological values, besides financial values, strongly influence farmer’s decision in implementing various practices related to the land use types. Thus, such values are worth considering for a holistic understanding of the diverse benefits of land uses. Finally, the strong preference for tree and shrub-based land use types is a good opportunity for enhancing tree and shrub growing to minimize the major environmental problems (e.g., soil degradation, wood shortage and deforestation) in the central highlands of Ethiopia.     

Photocatalytic oxidation of gaseous chlorinated organics over titanium dioxide

The photocatalytic oxidation of high levels of volatile chlorinated organic compounds in gas phase has been studied using a specially designed photoreactor. The influence of light intensity, initial water vapour concentration, temperature, inlet contaminant concentration and flow rate on destruction efficiency has been investigated. The performance of the titanium catalyst was strongly affected by the presence of water in the air stream. Experiments have been most successfully conducted at room temperature, low initial contaminant concentrations, low flow rates and high light intensities. Several by-products have been detected performing photocatalytic degradation of trichloroethylene (TCE) and tetrachloroethylene (PCE). No catalyst deactivation was observed.     

Grooves to tubes: evolution of the venom delivery system in a Late Triassic “reptile”

Venom delivery systems occur in a wide range of extant and fossil vertebrates and are primarily based on oral adaptations. Teeth range from unmodified (Komodo dragons) to highly specialized fangs similar to hypodermic needles (protero- and solenoglyphous snakes). Developmental biologists have documented evidence for an infolding pathway of fang evolution, where the groove folds over to create the more derived condition. However, the oldest known members of venomous clades retain the same condition as their extant relatives, resulting in no fossil evidence for the transition. Based on a comparison of previously known specimens with newly discovered teeth from North Carolina, we describe a new species of the Late Triassic archosauriform Uatchitodon and provide detailed analyses that provide evidence for both venom conduction and document a complete structural series from shallow grooves to fully enclosed tubular canals. While known only from teeth, Uatchitodon is highly diagnostic in possessing compound serrations and for having two venom canals on each tooth in the dentition. Further, although not a snake, Uatchitodon sheds light on the evolutionary trajectory of venom delivery systems in amniotes and provide solid evidence for venom conduction in archosaur-line diapsids.