800 research outputs found

    Long-term variations in fish assemblage, macrophyte community, and water quality in Lake Rotoroa (Hamilton Lake)

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    Lake Rotoroa (37Âș48’S, 175Âș16’E) is a small, shallow, polymictic lake located on the western side of Hamilton City. The lake covers an area of 0.54 km2 with a mean depth of 2.4 m, catchment and riparian margins have been significantly modified into a suburban park-like setting. Due to its urban location and recreational value, exotic flora and fauna have been intentionally and unintentionally introduced. This has resulted in fluctuations in water quality and changes in phytoplankton, fish, and macrophyte assemblages over the past 60 years. The overall aim of this thesis is to summarise the fluctuations in water quality and macrophyte community of Lake Rotoroa associated with introduction of exotic species, and to develop a general understanding of the ecosystem response. This study involved collating and analysing available information on fish assemblages, macrophyte community, and water quality in Lake Rotoroa. Data from nine fish surveys undertaken between 1976 and 2012 has been combined. Water quality and macrophyte data was supplied by NIWA, who have undertaken monitoring for Hamilton City Council as part of the national lakes monitoring programme. Fishing methods have varied from gill, trap, and fyke netting between 1976 and 2001, with boat electrofishing surveys between 2003 and 2012. Lake Rotoroa has a relatively diverse freshwater fish fauna, comprising two native and six exotic fish species. The fish assemblage is now dominated by the native shortfin eel (Anguilla australis), European perch (Perca fluviatilis), brown bullhead catfish (Ameiurus nebulosus), and tench (Tinca tinca), with low densities of rudd (Scardinius erythrophthalmus) and goldfish (Carassius auratus). Fish density and biomass have varied throughout the survey period, to some extent related to the environmental conditions and macrophyte cover. Macrophyte coverage and water quality have undergone considerable changes in the last 30 years, with the collapses of macrophytes stimulating decreases in water quality and increased perch abundance. In 1990, the macrophyte community collapsed with an associated release of nutrients into the water column, causing the lake to become supertrophic. Between 1992 and 2010, water quality improved, with a decrease phosphorus concentrations that apparently limited phytoplankton biomass and improved water clarity. This allowed macrophytes to recolonise the lake to 30% lake bed coverage in 2005 and a consequent improvement from supertrophic to a eutrophic state. Since 2009, the macrophyte community has undergone another collapse, with only a few clumps of native charophytes and Egeria densa present in 2011. The reduction of macrophytes has been accompanied by a decrease in water clarity. The collapse has been attributed to disturbance by grazing from the herbivorous rudd and foraging benthic feeding fish, although other stresses such as decreased water clarity and microcystins may also have had an influence. Further research is needed on the selectivity between passive and active fish capture methods used to allow accurate comparisons between the two methods. This will allow for density and biomass estimates to be made for the passive fishing methods previously used and allow greater insight into changes in abundance of fish populations in Lake Rotoroa

    Mixed metal nanoparticle assembly and the effect on surface enhanced raman scattering

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    Here we report the assembly of mixed metal nanoparticles using an oligonucleotide-templated approach. Substitution of one of the gold nanoparticle probes with an analagous silver probe to produce a hetero-metal duplex permitted surface enhanced Raman scattering of the dye label, exploiting the improved surface enhancement properties of silver nanoparticles whilst maintaining the surface chemistry benefits of gold nanoaprticle

    International Fund Services Limited (IFSL) Research - Hedge Funds 2009

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    Spaces for play:Listening to children's voices

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    This paper explores young children’s voices about their play spaces in one Scottish primary school. 45 children (ages 5-7 years) participated, choosing from a range of creative methods (e.g., InPhoTours, drawing, mapping) to share their voices. Using a ‘Playful Research Ethics Framework’, a developmentally appropriate framework which involved the use of visual aids, puppets, songs, Makaton symbols and discussions as well as attention to any cues of disengagement, this research aimed at achieving children’s ongoing informed assent. Four themes were identified: (a) the ‘whole child’ in the space, (b) space and relationships, (c) function of space, and (d) impact (or lack) of children’s voices about space. Children expressed differences in ownership, creativity and imagination in indoor and outdoor spaces. Further, despite perceiving there to be a lack of agency, children were willing to share their voices. There are implications for both practice and research in terms of adults willing to effectively listen to children’s voices and acting on them. This study makes original and significant contributions which have the potential to impact research and practice with young children internationally

    Spaces for play:Listening to children's voices

    Get PDF
    This paper explores young children’s voices about their play spaces in one Scottish primary school. 45 children (ages 5-7 years) participated, choosing from a range of creative methods (e.g., InPhoTours, drawing, mapping) to share their voices. Using a ‘Playful Research Ethics Framework’, a developmentally appropriate framework which involved the use of visual aids, puppets, songs, Makaton symbols and discussions as well as attention to any cues of disengagement, this research aimed at achieving children’s ongoing informed assent. Four themes were identified: (a) the ‘whole child’ in the space, (b) space and relationships, (c) function of space, and (d) impact (or lack) of children’s voices about space. Children expressed differences in ownership, creativity and imagination in indoor and outdoor spaces. Further, despite perceiving there to be a lack of agency, children were willing to share their voices. There are implications for both practice and research in terms of adults willing to effectively listen to children’s voices and acting on them. This study makes original and significant contributions which have the potential to impact research and practice with young children internationally

    Offering patients choices: A pilot study of interactions in the seizure clinic

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    Using conversation analysis (CA), we studied conversations between one United Kingdom-based epilepsy specialist and 13 patients with seizures in whom there was uncertainty about the diagnosis and for whom different treatment and investigational options were being considered. In line with recent communication guidance, the specialist offered some form of choice to all patients: in eight cases, a course of action was proposed, to be accepted or rejected, and in the remaining five, a "menu" of options was offered. Even when presenting a menu, the specialist sometimes conveyed his own preferences in how he described the options, and in some cases the menu was used for reasons other than offering choice (e.g., to address patient resistance). Close linguistic and, interactional analysis of clinical encounters can show why doctors may feel they are offering choices when patients report that the decision was clinician dominated. (C) 2010 Elsevier Inc. All rights reserved
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