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  • Disputas: 2017-02-24 10:15 Sjöströmsalen 1B309, 651 88 Karlstad
    Schneider, Lea Dominique
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för miljö- och livsvetenskaper.
    Conservation ecology of the thick-shelled river mussel Unio crassus : The importance of parasite-host interactions2017Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Unionoid mussels are globally threatened and their conservation requires species-specific knowledge on their ecology and parasite-host interaction. Unio crassus is one of Europe’s most threatened unionoid species and has a temporary obligate parasitic life stage (glochidia) on fish. A lack of suitable hosts is probably a major limitation for mussel recruitment, but host species composition, suitability and availability in time and space have yet to be fully explored. This thesis examines different aspects of the host fish species, including their composition, suitability and ecological importance, in relation to U. crassus, using both field and laboratory studies. The effects of mussel and host density on mussel reproductive potential were considered, as were aspects of evolutionary adaptations between mussels and fish and how climate change may affect their interaction.

    The results show that U. crassus is a host generalist, parasitizing a variety of fish species. Host suitability and density, which varied among fish species and rivers, affected the level of glochidia encapsulation, hence mussel reproductive potential, more so than the density of mussels taking part in reproduction. Ecologically important hosts included both highly suitable primary hosts, and less suitable hosts that were highly abundant. Whether or not U. crassus has specific adaptations to its hosts to enhance juvenile transformation remains unclear. No distinct pattern of local adaptation was found, nor was there an effect of host fish presence on the timing of glochidia release by adult mussels. Instead, temperature played a major role, with results suggesting that changes in spring water temperature regimes can cause temporal and spatial mismatches in the mussel-host interaction. This thesis indicates that investigations of local mussel-host interactions help in identifying mechanisms important for unionoid conservation management and prioritization.

  • Disputas: 2017-02-24 13:00 9c 203, Karlstad
    Duek, Susanne
    Karlstads universitet, Fakulteten för humaniora och samhällsvetenskap (from 2013), Institutionen för pedagogiska studier.
    Med andra ord: Samspel och villkor för litteracitet bland nyanlända barn2017Doktoravhandling, monografi (Annet vitenskapelig)
    Abstract [en]

    This doctoral thesis centres on six children, aged four to nine, who relatively recently immigrated to Sweden. The children’s encounters with literacy are in focus. These children are not only new arrivals to Sweden, they also have in common that Swedish is their second language and that their parents have had little or no formal education prior to arriving in Sweden. The study draws on sociocultural approaches to literacy, and more specifically the field of New Literacy Studies. In this study, reading and writing are viewed as social practices comprising different related sociocultural aspects such as norms, values, habits, traditions and ideologies, and the study concentrates on social and ideological perspectives on literacy. Bourdieu’s notions of habitus and symbolic capital have also been used for the analysis.

    The empirical material was collected through an ethnographic approach. Each child was followed for one year, particularly at school/preschool. The children’s homes were also visited, and their parents and teachers were interviewed. Observations involved different degrees of participation and were documented through field notes and photographs. The interviews were audio-recorded and transcribed. In addition, artefacts and school material from the field were collected or photographed. A qualitative content analysis of the collected data was performed.

    The analysis show that sociocultural incongruence, coupled with flawed communication between the schools and the homes, caused the children less continuity between school and home practices. Though, the results also show, that the children studied to a considerable extent adapted to the monolingual, homogenous norms when they participated in school practices. These children are therefore highly adaptable, while their teachers found it much harder to handle or even be aware of sociocultural incongruences.