http://hdl.handle.net/10453/63 2013-05-21T03:41:55Z http://hdl.handle.net/10453/17522 Species interactions: complex effects Dickman C; Murray Brad Attiwell, P; Wilson, B. Interactions within ecological communities usually involve many species and pose intriguing challenges for ecologists who wish to map and disentangle them. To simplify this task we often assume that the interactions do not change in strength or direction and that the identities of the key species remain the same. Species can be 'pigeon-holed' into convenient categories such as 'pollinator', 'competitor', 'pest' or even 'redundant' using these assumptions. This makes programs of conservation or pest management easier to implement, but is also ignores an emerging body of evidence that interactions between species vary between situations, places and times. In this chapter we will explore the complexity of effects that arise from changes in tereactions between species. We also consider how such effects may be modelled and predicted,a nd illustrate how ecological insight can be used to guide management decisions. 2006-01-01T00:00:00Z http://hdl.handle.net/10453/14254 Dietary intake of potentially toxic elements from vegetables Rahman Mohammad; Rahman Mohammad; Rahman Ismail; Hasegawa Hiroshi A. Pepareschi, & H. Eppolito Toxic elements e.g B,arsenic(As),cadmim (Cd),ChrOmium(Co,COpper(Cu),lCad (Pb),and zinc(Zn)are the chief env¿Þolllnental pollutants which can cause deleterious health effects ill humans.Inhalation and consumption ofrnetal c conta \ated food are the mttOr pathways of metal entrance into hman body.Cuhivation of crop plants in the metal \ contaminated soils induces the bioaccllmlllation of toxic elements in the food chain.Among different food items,vegetables have mttOr cOntribution in the daily dict, and the heavy inetal contamination ofvegetables poses a threat to human health with the prevalence of skin and gastrointerestinal cancer. 2009-01-01T00:00:00Z http://hdl.handle.net/10453/14253 Arsenic adsorption on iron plaque and uptake in duckweed (Spirodela polyrhiza L.) affected by chemical species Rahman Mohammad; Hasegawa Hiroshi; Ueda Kazumasa; Maki Teruya; Okumura Chikuko; Rahman Mohammad S. K. Starrett, J. Hong, R. J. Wilcock, Q. Li, J. H. Carson, & S. Arnold The effect of iron plaque formation on plant surfaces and chemical species on arsenic uptake in Spirodela polyrhiza L. were investigated. Arsenate [As(V)] or arsenite [As(III)] concentration in S. polyrhiza L. was significantly (p < 0.05) higher than that of methyl arsenic species (MMAA or DMAA). In particular, the concentrations of As(V) and As(III) in CBE-extracts of plants with Fe-plaque were about 43% and 58% respectively higher then plants without Fe-plaque,. On the other hand, the As(V) and As(III) concentrations in tissues of plants with or without Fe-plaque remained almost unchanged. The results suggest that a significant amount of arsenate and arsenite were adsorbed on the Fe-plaque of S. polyrhiza L. surfaces. The concentrations of MMAA and DMAA in tissues and on CBEextracts of S. polyrhiza L. were not significantly affected (p > 0.05) by the Fe-plaque on plant surfaces. These results indicate that methyl arsenic species might not be adsorbed on Fe-plaques. However, the significantly higher concentration of MMAA into the plant tissues than that of DMAA suggests that MMAA is more bioavailable to this plant. The ratios of As/P and As/Fe were significantly higher in tissues and CBE-extracts of plants exposed to inorganic arsenic species than plants exposed to methyl arsenic species. The results indicate enhanced uptake and adsorption of As(V) and As(III) than MMAA and DMAA in relation to phosphate and iron. 2007-01-01T00:00:00Z http://hdl.handle.net/10453/12404 Synergy in the city: making the sum of the parts more than the whole Mitchell Cynthia; Campbell Sally Beck, M.B. and Speers, A. The pressures on existing infrastructures are significant: demand is beginning to outstrip supply; aging infrastructure poorly maintained presents an increasing risk; and rejection of urban sprawl forces increasing population density. At the same time, the drivers for infrastructure are changing. We are beginning to recognise ecological limits to supply, leading to shifting expectations, for example, from 'remove waste' to 'recapture nutrients'. We now know that a sustainable future requires step changes in material use intensity, which has further infrastructure implications. We have witnessed it already in communications. For water and energy, and therefore, for transport also, the step changes are on the horizon. Community expectations are moving too, for example, from separating home and work towards co-locating them. 2006-01-01T00:00:00Z