Tree species-area and species-diameter relationships at three lowland rain forest sites in Sumatra

Data from three forest sites in Sumatra (Batang Ule, Pasirmayang and Tebopandak) have been analysed and compared for the effects of sample area cut-off, and tree diameter cut-off. An 'extended inverted exponential model' is shown to be well suited to fitting tree-species-area curves. The model yields species carrying capacities of 680 for Batang Ule, 380 species for Pasirmayang, and 35 for Tebopandak (tree diameter >10cm). It would seem that in terms of species carrying capacity, Tebopandak and Pasirmayang are rather similar, and both less diverse than the hilly Batang Ule site. In terms of conservation policy, this would mean that rather more emphasis should be put on conserving hilly sites on a granite substratum. For Pasirmayang with tree diameter >3cm, the asymptotic species number estimate is 567, considerably higher than the estimate of 387 species for trees with diameter >10cm. It is clear that the diameter cut-off has a major impact on the estimate of the species carrying capacity. A conservative estimate of the total number of tree species in the Pasirmayang region is 632 species! In sampling exercises, the diameter cut-off should not be chosen lightly, and it may be worth adopting field sampling procedures which involve some subsampling of the primary sample area, where the diameter cut-off is set much lower than in the primary plots.

An investigation of assessment policy and practices in terms of broad social and educational purposes

Based upon relevant literature, this study investigated the assessment policy and practices for the BSc (Hons) Computing Science programme at the University of Greenwich (UOG), contextualising these in terms of broad social and educational purposes. It discusses Assessment, and then proceeds to give a critical evaluation of the assessment policy and practices at the UOG. Although this is one case study, because any of the features of the programme are generic to other programmes and institutions, it is of wider value and has further implications. The study was concluded in the summer of 2002. It concludes that overall, the programme's assessment policy and practices are well considered in terms of broad social and educational purposes, although it identifies and outlines several possible improvements, as well as raising some major issues still to be addressed which go beyond assessment practices.

Comparative antioxidant, prooxidant and cytotoxic activity of sigmoidin A and eriodictyol

Sigmoidin A (SGN) is a prenylated flavanone derivative of eriodictyol (ERD) with reported moderate antioxidant, antimicrobial and anti-inflammatory activity. Since ERD and other structurally similar antioxidant phenolic compounds have been shown to induce prooxidative macromolecular damage and cytotoxicity in cancer cells, the comparative in vitro effects of these structural analogues on cancer cell viability and Cu(II)-dependent DNA damage were studied. In the presence of Cu(II) ions, both SGN and ERD (7.4-236 µM) caused comparable concentration-dependent pBR322 plasmid DNA strand scission. The DNA damage induced by SGN and ERD could be abolished by ROS scavengers, glutathione (GSH) and catalase as well as EDTA and a specific Cu(I) chelator neocuproine. Both ERD and SGN readily reduce Cu(II) to Cu(I) suggesting a prooxidative mechanism of DNA damage. In a cell free system, ERD and SGN did also show comparable radical scavenging activity. SGN was, however, by an order of magnitude more cytotoxic to cancer cells than ERD and this effect was significantly attenuated by GSH suggesting a prooxidative mechanism of cell death. A depletion of intracellular GSH level by SGN in cancer cells is also demonstrated.

Safe spaces and sense of identity: views and experiences of lesbian, gay and bisexual young people

Empirical data on the life experiences of contemporary school-age lesbian, gay and bisexual (LGB) young people in Britain remains somewhat sparse. This paper reports the preliminary findings of a study conducted at a recently-initiated LGB youth Summer School. To further an appreciation of issues of concern to today's LGB teenagers, in-depth interviews were conducted with 10 Summer School participants (five female and five male, aged 15-18 years). The aim was to elicit their views and experiences relating to their need for support such as that offered by the Summer School. Themes drawn from participants' interviews are presented. Key issues included: being positioned as different by their majority heterosexual peers; feelings of isolation and loneliness in their peer groups and families; difficulties in finding others like themselves for companionship; and the importance of meeting more LGB people of their own age.