“Islands” in Holocene forests: implications for forest openness, landscape clearance and “culture-steppe” species

Human activity has undoubtedly had a major impact on Holocene forested ecosystems, with the concurrent expansion of plants and animals associated with cleared landscapes and pasture, also known as 'culture-steppe'. However, this anthropogenic perspective may have underestimated the contribution of autogenic disturbance (e.g. wind-throw, fire), or a mixture of autogenic and anthropogenic processes, within early Holocene forests. Entomologists have long argued that the north European primary forest was probably similar in structure to pasture woodland. This idea has received support from the conservation biologist Frans Vera, who has recently strongly argued that the role of large herbivores in maintaining open forests in the primeval landscapes of Europe has been seriously underestimated. This paper reviews this debate from a fossil invertebrate perspective and looks at several early Holocene insect assemblages. Although wood taxa are indeed important during this period, species typical of open areas and grassland and dung beetles, usually associated with the dung of grazing animals, are persistent presences in many early woodland faunas. We also suggest that fire and other natural disturbance agents appear to have played an important ecological role in some of these forests, maintaining open areas and creating open vegetation islands within these systems. More work, however, is required to ascertain the role of grazing animals, but we conclude that fossil insects have a significant contribution to make to this debate. This evidence has fundamental implications in terms of how the palaeoecological record is interpreted, particularly by environmental archaeologists and palaeoecologists who may be more interested in identifying human-environment interactions rather than the ecological processes which may be preserved within palaeoecological records.

Isolation and culture of mouse intestinal cells.

Complex cell signal transduction mechanisms regulate intestinal epithelial shape, polarity, motility, organelles, cell membrane components as well as physical and mechanical properties to influence alimentary digestion, absorption, secretion, detoxification and fluid balance. Interactions between the epithelial cells and adjacent mesenchyme are central to intestinal homeostasis although the key regulatory molecules of specific differentiation steps remain unclear. Isolation and primary culture of heterotypic murine intestinal cells provides a model system for elucidation of essential molecular cross-talk between epithelium and mesenchyme that may provide several biological and practical advantages over transformed cell lines. An in vitro primary culture system for neonatal rat or mouse intestinal cells has been established that forms monolayers, expresses intestine-specific epithelial features including intestinal brush borders and appropriate hydrolase enzymes. Our studies confirm the promise of this method which may advance our understanding of heterotypic cellular interactions implicated in intestinal function and may provide important insights into the pathobiology of disease.

Informalilty in the Social and Culture Life in the City Centre of Nairobi

We live in a world of advanced technology, stiff global competition and rapid transformation of all facets of life and as a result architecture has not been spared. These transformations affect the social relations, cultural consumption and political economy that have influenced the manner in which people perform in and out of space in the city centres. The residents have adopted strategies for negotiating through the spaces sanitized by authorities and other agents. The public spaces provide the background materials for informal urban practices that are sometimes deemed illegal yet are necessary for animating the city spaces. Cities market themselves ecstatically beyond the baroque with a more visible presence of the contending parties through trademarks, public relations invasively advertised in streets, monuments (signature buildings or projects), and language. This paper comes out of a research carried out in Nairobi in February and March 2007. It examined how the notions of globalisation are reflected in the life in the city centre; the impacts on the quality of life of users of the city centre and how informal urbanism has developed as copying strategy to deal with the transformations due to liberalization and globalization.