39 resultados para Fish communities
Resumo:
The Internet has transformed the scope, boundaries and dynamics of social and economic interactions. It is argued to have broadened the notion of the community from physical, colocated groups towards collectives that are able to transcend time and space, i.e. virtual communities. Even if virtual communities have been on the academic agenda for a couple of decades, there is still surprisingly little research on knowledge sharing within them. In addition, prior research has largely neglected the complex dynamics between Internet-based communication channels and the surrounding communities in which they are embedded. This thesis aims at building a better understanding of knowledge sharing supported by conversational technologies in intra-organisational virtual communities and external virtual communities supporting relationships with customers. The focus is thus on knowledge sharing in types of virtual communities that seem to be of relevance to business organisations. The study consists of two parts. The first part introduces the research topic and discusses the overall results. The second part comprises seven research publications. Qualitative research methods are used throughout the study. The results of the study indicate that investigation of the processes of knowledge sharing in virtual communities requires a socio-technical perspective, combining the individual, social and technological levels, and understanding the interplay between them. It is claimed that collective knowledge in virtual communities creates the enabling structure for knowledge sharing, and forms the invisible structure of the community on the basis of which it operates. It consists of a shared context, social capital and a unique community culture. The Internet does not inevitably erode social interaction: it seems that supporting social relationships by means of communication technology is a matter of quantity rather than quality. In order to provide access to external knowledge and expertise, firms need to open themselves up to an array of Internet-based conversations, and to consider the relevance of virtual communities to their businesses.
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Virtual communities – interactive networks in cyberspace seasoned with feelings – are a highly topical research theme. Besides academics, more and more companies ponder upon the nature and implications of the sense of virtual communities. This thesis takes a novel viewpoint on this research and examines virtual communities from virtual ba perspective. Ba is the space – in this case a virtual and a mental one, where knowledge based interaction occurs. The aim of this thesis is to clarify the concept of virtual ba, and the development and appearance of ba in virtual communities. The scientific contribution of this qualitative case study is conceptual clarification and validation of the concept of virtual ba. The empirical part of the thesis examines blogs: Internet-based communication media, using data triangulation (observation, narratives and a thematic interview). The thesis provides insights into the development of virtual ba that has also managerial relevance.
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This Master's thesis studies the development of interaction and socialization in online communities. A large number of online communities fade away even before they really get started. In many occasions the reason is that the community does not give anything new, or even if they do, the delivery does not satisfy the users. In this thesis guidelines were developed to help to see important things, which might be forgotten when developing an online community. The thesis goes through the characteristic of an online community and human behaviour related to them and also compares behaviour in the Internet and real life. In addition, usability is an important part of the online communities and thus it is also covered in this thesis. As a result of this thesis an 8-step guideline was developed to ease the design of an online community. Guidelines were also applied to two real life cases which are described as one part of this work.
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This thesis centers to three firm-hosted online communities which operate in the field of software development. The communities were analyzed by using a particular design framework. This thesis investigates how companies can benefit from firm-hosted online communities and how well the design principles are present in analyzed communities. The framework also gives perspective and indicators which enables the possibility to analyze and compare communities with each other. This thesis also discuss how well a design framework designed for measuring social software fits to measuring online communities of software development.
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The purpose of this study is to study whether a Web CMS can be used to implement and host an online community. The study is divided into two parts. The theoretical part contains the definition of Web CMS and clarifies the relation between an online community and a social software. The first part also defines the parameters, which must be taken account when choosing a Web CMS for hosting an online community. The practical part of the study contains analyses of three Web CMSs, Drupal, Liferay and Plone. All the three Web CMSs were analyzed using the technical and social parameters discovered in the theoretical part of the study. The primary objective is to investigate whether the selected Web CMS can be used to implement and host an online community. If hosting is possible, the secondary objective is to investigate whether the selected Web CMS have an effect to the online community.
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Crossroads, crucibles and refuges are three words that may describe natural coastal lagoon environments. The words refer to the complex mix of marine and terrestrial influences, prolonged dilution due to the semi-enclosed nature and the function of a habitat for highly diverse plant and animal communities, some of which are endangered. To attain a realistic picture of the present situation, high vulnerability to anthropogenic impact should be added to the description. As the sea floor in coastal lagoons is usually entirely photic, macrophyte primary production is accentuated compared with open sea environments. There is, however, a lack of proper knowledge on the importance of vegetation for the general functioning of coastal lagoon ecosystems. The aim of this thesis is to assess the role of macrophyte diversity, cover and species identity over temporal and spatial scales for lagoon functions, and to determine which steering factors primarily restrict the qualitative and quantitative composition of vegetation in coastal lagoons. The results are linked to patterns of related trophic levels and the indicative potential of vegetation for assessment of general conditions in coastal lagoons is evaluated. This thesis includes five field studies conducted in flads and glo-flads in the brackish water northern Baltic Sea. Flads and glo-flads are defined as a Baltic variety of coastal lagoons, which due to an inlet threshold and post-glacial landuplift slowly will be isolated from the open sea. This process shrinks inlet size, increases exposure and water retention, and is called habitat isolation. The studied coastal lagoons are situated in the archipelago areas of the eastern coast of Sweden, the Åland Islands and the south-west mainland of Finland, where land-uplift amounts to ca. 5 mm/ per year. Out of 400 evaluated sites, a total of 70 lagoons varying in inlet size, archipelago position and anthropogenic influence to cover for essential environmental variation were chosen for further inventory. Vegetation composition, cover and richness were measured together with several hydrographic and morphometric variables in the lagoons both seasonally and inter-annually to cover for general regional, local and temporal patterns influencing lagoon and vegetation development. On smaller species-level scale, the effects of macrophyte species identity and richness for the fish habitat function were studied by examining the influence of plant interaction on juvenile fish diversity. Thus, the active election of plant monoand polycultures by fish and the diversity of fish in the respective culture were examined and related to plant height and water depth. The lagoons and vegetation composition were found to experience a regime shift initiated by increased habitat isolation along with land-uplift. Vegetation composition altered, richness decreased and cover increased forming a less isolated and more isolated regime, named the vascular plant regime and charophyte regime, respectively according to the dominant vegetation. As total phosphorus in the water, turbidity and the impact of regional influences decreased in parallel, the dominance of charophytes and increasing cover seemed to buffer and stabilize conditions in the charophyte regime and indicated an increased functional role of vegetation for the lagoon ecosystem. The regime pattern was unaffected by geographical differences, while strong anthropogenic impact seemed to distort the pattern due to loss of especially Chara tomentosa L. in the charophyte regime. The regimes were further found unperturbed by short-time temporal fluctuations. In fact the seasonal and inter-annual dynamics reinforced the functional difference between the regimes by the increasing role of vegetation along habitat isolation and the resemblance to lake environments for the charophyte regime. For instance, greater total phosphorus and chlorophyll a concentrations in the water in the beginning of the season in the charophyte regime compared with the vascular plant regime presented a steeper reduction to even lower values than in the vascular plant regime along the season. Despite a regional importance and positive relationship of macrophyte diversity in relation to trophic diversity, species identity was underlined in the results of this thesis, especially with decreasing spatial scale. This result was supported partly by the increased role of charophytes in the functioning of the charophyte regime, but even more explicitly by the species-specific preference of juvenile fish for tall macrophyte monocultures. On a smaller species-level scale, tall plant species in monoculture seemed to be able to increase their length, indicating that negative selection forms preferred habitat structures, which increase fish diversity. This negative relationship between plant and fish diversity suggest a shift in diversity patterns among trohic levels on smaller scale. Thus, as diversity patterns seem complex and diverge among spatial scales, it might be ambiguous to extend the understanding of diversity relationships from one trophic level to the other. All together, the regime shift described here presents similarities to the regime development in marine lagoon environments and shallow lakes subjected to nutrient enrichment. However, due to nutrient buffering by vegetation with increased isolation and water retention as a consequence of the inlet threshold, the development seems opposite to the course along an eutrophication gradient described in marine lagoons lacking an inlet threshold, where the role of vegetation decreases. Thus, the results imply devastating consequences of inlet dredging (decreasing isolation) in terms of vegetation loss and nutrient release, and call for increased conservational supervision. Especially the red listed charophytes would suffer negatively from such interference and the consequences are likely to also deteriorate juvenile fish production. The fact that a new species to Finland, Chara connivens Salzm. Ex. Braun 1835 was discovered during this study further indicates a potential of the lagoons serving as refuges for rare species.
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Kirjallisuusarvostelu
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Increased emissions of greenhouse gases into the atmosphere are causing an anthropogenic climate change. The resulting global warming challenges the ability of organisms to adapt to the new temperature conditions. However, warming is not the only major threat. In marine environments, dissolution of carbon dioxide from the atmosphere causes a decrease in surface water pH, the so called ocean acidification. The temperature and acidification effects can interact, and create even larger problems for the marine flora and fauna than either of the effects would cause alone. I have used Baltic calanoid copepods (crustacean zooplankton) as my research object and studied their growth and stress responses using climate predictions projected for the next century. I have studied both direct temperature and pH effects on copepods, and indirect effects via their food: the changing phytoplankton spring bloom composition and toxic cyanobacterium. The main aims of my thesis were: 1) to find out how warming and acidification combined with a toxic cyanobacterium affect copepod reproductive success (egg production, egg viability, egg hatching success, offspring development) and oxidative balance (antioxidant capacity, oxidative damage), and 2) to reveal the possible food quality effects of spring phytoplankton bloom composition dominated by diatoms or dinoflagellates on reproducing copepods (egg production, egg hatching, RNA:DNA ratio). The two copepod genera used, Acartia sp. and Eurytemora affinis are the dominating mesozooplankton taxa (0.2 – 2 mm) in my study area the Gulf of Finland. The 20°C temperature seems to be within the tolerance limits of Acartia spp., because copepods can adapt to the temperature phenotypically by adjusting their body size. Copepods are also able to tolerate a pH decrease of 0.4 from present values, but the combination of warm water and decreased pH causes problems for them. In my studies, the copepod oxidative balance was negatively influenced by the interaction of these two environmental factors, and egg and nauplii production were lower at 20°C and lower pH, than at 20°C and ambient pH. However, presence of toxic cyanobacterium Nodularia spumigena improved the copepod oxidative balance and helped to resist the environmental stress, in question. In addition, adaptive maternal effects seem to be an important adaptation mechanism in a changing environment, but it depends on the condition of the female copepod and her diet how much she can invest in her offspring. I did not find systematic food quality difference between diatoms and dinoflagellates. There are both good and bad diatom and dinoflagellate species. Instead, the dominating species in the phytoplankton bloom composition has a central role in determining the food quality, although copepods aim at obtaining as a balanced diet as possible by foraging on several species. If the dominating species is of poor quality it can cause stress when ingested, or lead to non-optimal foraging if rejected. My thesis demonstrates that climate change induced water temperature and pH changes can cause problems to Baltic Sea copepod communities. However, their resilience depends substantially on their diet, and therefore the response of phytoplankton to the environmental changes. As copepods are an important link in pelagic food webs, their future success can have far reaching consequences, for example on fish stocks.
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The biological variation in nature is called biodiversity. Anthropogenic pressures have led to a loss of biodiversity, alarming scientists as to what consequences declining diversity has for ecosystem functioning. The general consensus is that diversity (e.g. species richness or identity) affects functioning and provides services from which humans benefit. The aim of this thesis was to investigate how aquatic plant species richness and identity affect ecosystem functioning in terms of processes such as primary production, nutrient availability, epifaunal colonization and properties e.g. stability of Zostera marina subjected to shading. The main work was carried out in the field and ranged temporally from weeklong to 3.5 months-long experiments. The experimental plants used frequently co-occur in submerged meadows in the northern Baltic Sea and consist of eelgrass (Z. marina), perfoliate pondweed (Potamogeton perfoliatus), sago pondweed (P. pectinatus), slender-leaved pondweed (P. filiformis) and horned pondweed (Zannichellia palustris). The results showed that plant richness affected epifaunal community variables weakly, but had a strong positive effect on infaunal species number and functional diversity, while plant identity had strong effects on amphipods (Gammarus spp.), of which abundances were higher in plant assemblages consisting of P. perfoliatus. Depending on the starting standardizing unit, plant richness showed varying effects on primary production. In shoot density-standardized plots, plant richness increased the shoot densities of three out of four species and enhanced the plant biomass production. Both positive complementarity and selection effects were found to underpin the positive biodiversity effects. In shoot biomass-standardized plots, richness effects only affected biomass production of one species. Negative selection was prevalent, counteracting positive complementarity, which resulted in no significant biodiversity effect. The stability of Z. marina was affected by plant richness in such that Z. marina growing in polycultures lost proportionally less biomass than Z. marina in monocultures and thus had a higher resistance to shading. Monoculture plants in turn gained biomass faster, and thereby had a faster recovery than Z. marina growing in polycultures. These results indicate that positive interspecific interactions occurred during shading, while the faster recovery of monocultures suggests that the change from shading stress to recovery resulted in a shift from positive interactions to resource competition between species. The results derived from this thesis show that plant diversity affects ecosystem functioning and contribute to the growing knowledge of plant diversity being an important component of aquatic ecosystems. Diverse plant communities sustain higher primary productivity than comparable monocultures, affect faunal communities positively and enhance stability. Richness and identity effects vary, and identity has generally stronger effects on more variables than richness. However, species-rich communities are likely to contain several species with differing effects on functions, which renders species richness important for functioning. Mixed meadows add to coastal ecosystem functioning in the northern Baltic Sea and may provide with services essential for human well-being.
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Thousands of tons of pharmaceuticals are consumed yearly worldwide. Due to the continuous and increasing consumption and their incomplete elimination in wastewater treatment plants (WWTP), pharmaceuticals and their metabolites can be detected in receiving waters, although at low concentrations (ng to low μg/L). As bioactive molecules the presence of pharmaceuticals in the aquatic environment must be considered potentially hazardous for the aquatic organisms. In this thesis, the biotransformation and excretion of pharmaceuticals in fish was studied. The main biotransformation pathways of three anti‐inflammatory drugs, diclofenac, naproxen and ibuprofen, in rainbow trout were glucuronidation and taurine conjugation of the parent compounds and their phase I metabolites. The same metabolites were present in fish bile in aquatic exposures as in fish dosed with intraperitoneal injection. Higher bioconcentration factor in bile (BCFbile) was found for ibuprofen when compared to diclofenac and naproxen. Laboratory exposure studies were followed by a study of uptake of pharmaceuticals in a wild fish population living in lake contaminated with WWTP effluents. Of the analyzed 17 pharmaceuticals and six phase I metabolites, only diclofenac, naproxen and ibuprofen was present in bream and roach bile. It was shown, that diclofenac, naproxen and ibuprofen excreted by the liver can be found in rainbow trout and in two native fish species living in the receiving waters. In the bream and roach bile, the concentrations of diclofenac, naproxen and ibuprofen were roughly 1000 times higher than those found in the lake water, while in the laboratory exposures, the bioconcentration of the compounds and their metabolites in rainbow trout bile were at the same level as in wild fish or an order of magnitude higher. Thus, the parent compounds and their metabolites in fish bile can be used as a reliable biomarker to monitor the exposure of fish to environmental pharmaceuticals present in water receiving discharges from WWTPs.
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End-user development is a very common but often largely overlooked phenomenon in information systems research and practice. End-user development means that regular people, the end-users of software, and not professional developers are doing software development. A large number of people are directly or indirectly impacted by the results of these non-professional development activities. The numbers of users performing end-user development activities are difficult to ascertain precisely. But it is very large, and still growing. Computer adoption is growing towards 100% and many new types of computational devices are continually introduced. In addition, other devices not previously programmable are becoming so. This means that, at this very moment, hundreds of millions of people are likely struggling with development problems. Furthermore, software itself is continually being adapted for more flexibility, enabling users to change the behaviour of their software themselves. New software and services are helping to transform users from consumers to producers. Much of this is now found on-line. The problem for the end-user developer is that little of this development is supported by anyone. Often organisations do not notice end-user development and consequently neither provide support for it, nor are equipped to be able to do so. Many end-user developers do not belong to any organisation at all. Also, the end-user development process may be aggravating the problem. End-users are usually not really committed to the development process, which tends to be more iterative and ad hoc. This means support becomes a distant third behind getting the job done and figuring out the development issues to get the job done. Sometimes the software itself may exacerbate the issue by simplifying the development process, deemphasising the difficulty of the task being undertaken. On-line support could be the lifeline the end-user developer needs. Going online one can find all the knowledge one could ever need. However, that does still not help the end-user apply this information or knowledge in practice. A virtual community, through its ability to adopt the end-user’s specific context, could surmount this final obstacle. This thesis explores the concept of end-user development and how it could be supported through on-line sources, in particular virtual communities, which it is argued here, seem to fit the end-user developer’s needs very well. The experiences of real end-user developers and prior literature were used in this process. Emphasis has been on those end-user developers, e.g. small business owners, who may have literally nowhere to turn to for support. Adopting the viewpoint of the end-user developer, the thesis examines the question of how an end-user could use a virtual community effectively, improving the results of the support process. Assuming the common situation where the demand for support outstrips the supply.
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Poster at Open Repositories 2014, Helsinki, Finland, June 9-13, 2014
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Presentation at Open Repositories 2014, Helsinki, Finland, June 9-13, 2014
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This study examines the aftermath of mass violence in local communities. Two rampage school shootings that occurred in Finland are analyzed and compared to examine the ways in which communities experience, make sense of, and recover from sudden acts of mass violence. The studied cases took place at Jokela High School, in southern Finland, and at a polytechnic university in Kauhajoki, in western Finland, in 2007 and 2008 respectively. Including the perpetrators, 20 people lost their lives in these shootings. These incidents are part of the global school shooting phenomenon with increasing numbers of incidents occurring in the last two decades, mostly in North America and Europe. The dynamic of solidarity and conflict is one of the main themes of this study. It builds upon previous research on mass violence and disasters which suggests that solidarity increases after a crisis, and that this increase is often followed by conflict in the affected communities. This dissertation also draws from theoretical discussions on remembering, narrating, and commemorating traumatic incidents, as well as the idea of a cultural trauma process in which the origins and consequences of traumas are negotiated alongside collective identities. Memorialization practices and narratives about what happened are vital parts of the social memory of crises and disasters, and their inclusive and exclusive characteristics are discussed in this study. The data include two types of qualitative interviews; focused interviews with 11 crisis workers, and focused, narrative interviews with 21 residents of Jokela and 22 residents of Kauhajoki. A quantitative mail survey of the Jokela population (N=330) provided data used in one of the research articles. The results indicate that both communities experienced a process of simultaneous solidarity and conflict after the shootings. In Jokela, the community was constructed as a victim, and public expressions of solidarity and memorialization were promoted as part of the recovery process. In Kauhajoki, the community was portrayed as an incidental site of mass violence, and public expressions of solidarity by distant witnesses were labeled as unnecessary and often criticized. However, after the shooting, the community was somewhat united in its desire to avoid victimization and a prolonged liminal period. This can be understood as a more modest and invisible process of “silent solidarity”. The processes of enforced solidarity were partly made possible by exclusion. In some accounts, the family of the perpetrator in Jokela was excluded from the community. In Kauhajoki, the whole incident was externalized. In both communities, this exclusion included associating the shooting events, certain places, and certain individuals with the concept of evil, which helped to understand and explain the inconceivable incidents. Differences concerning appropriate emotional orientations, memorialization practices and the pace of the recovery created conflict in both communities. In Jokela, attitudes towards the perpetrator and his family were also a source of friction. Traditional gender roles regarding the expression of emotions remained fairly stable after the school shootings, but in an exceptional situation, conflicting interpretations arose concerning how men and women should express emotion. The results from the Jokela community also suggest that while increased solidarity was seen as important part of the recovery process, some negative effects such as collective guilt, group divisions, and stigmatization also emerged. Based on the results, two simultaneous strategies that took place after mass violence were identified; one was a process of fast-paced normalization, and the other was that of memorialization. Both strategies are ways to restore the feeling of security shattered by violent incidents. The Jokela community emphasized remembering while the Kauhajoki community turned more to the normalization strategy. Both strategies have positive and negative consequences. It is important to note that the tendency to memorialize is not the only way of expressing solidarity, as fast normalization includes its own kind of solidarity and helps prevent the negative consequences of intense solidarity.
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Shallow coastal areas are dynamic habitats that are affected by a variety of abiotic and biotic factors. In addition to the natural environmental stress, estuarine and coastal seagrass ecosystems are exposed to effects of climate change and other anthropogenic impacts. In this thesis the effect of different abiotic (shading stress, salinity and temperature) and biotic stressors (presence of co-occurring species) and different levels and combinations of stressors on the performance and survival of eelgrass (Zostera marina) was assessed. To investigate the importance of scale for stress responses, varying levels of biological organization (genotype, life stage, population and plant community) were studied in field and aquarium experiments. Light limitation, decreased salinity and increased temperature affected eelgrass performance negatively in papers I, II and III, respectively. While co-occurring plant species had no notable effect on eelgrass in paper IV, the presence of eelgrass increased the biomass of Potamogeton perfoliatus. The findings in papers II and III confirmed that more extreme levels of salinity and temperature had stronger impacts on plant performance compared to intermediate levels, but intermediate levels also had more severe effects on plants when they were exposed to several stressors, as illustrated in paper II. Thus, multiple stressors had negative synergetic effects. The results in papers I, II and III indicate that future changes in light climate, salinity and temperature can have serious impacts on eelgrass performance and survival. Stress responses were found to vary among genotypes, life stages and populations in papers I, II and III, respectively, emphasizing the importance of study scale. The results demonstrate that while stress in general affects seagrass productivity negatively, the severity of effects can vary substantially depending on the studied scale or level of biological organization. Eelgrass genotypes can differ in their stress and recovery processes, as observed in paper I. In paper II, eelgrass seedlings were less prone to abiotic stress compared to adult plants, but stress also decreased their survival considerably. This indicates that recruitment and re-colonization through seeds might be threatened in the future. Variation among population responses observed in paper III indicates that long-term local adaptation under differing selection pressures has caused divergence in salinity tolerance between Baltic eelgrass populations. This variability in stress tolerance observed in papers I and III suggests that some eelgrass genotypes and populations have a better capacity to adapt to changes and survive in a changing environment. Multiple stressors and biological level-specific responses demonstrate the uncertainty in predicting eelgrass responses in a changing environment. As eelgrass populations may differ in their stress tolerance both within and across regions, conservation strategies at both local and regional scales are urgently needed in order to ensure the survival of these important ecosystems.