11 resultados para Ecological stoichiometry

em Doria (National Library of Finland DSpace Services) - National Library of Finland, Finland


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The main objective of this study was todo a statistical analysis of ecological type from optical satellite data, using Tipping's sparse Bayesian algorithm. This thesis uses "the Relevence Vector Machine" algorithm in ecological classification betweenforestland and wetland. Further this bi-classification technique was used to do classification of many other different species of trees and produces hierarchical classification of entire subclasses given as a target class. Also, we carried out an attempt to use airborne image of same forest area. Combining it with image analysis, using different image processing operation, we tried to extract good features and later used them to perform classification of forestland and wetland.

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The underlying cause of many human autoimmune diseases is unknown, but several environmental factors are implicated in triggering the self-destructive immune reactions. Multiple Sclerosis (MS) is a chronic autoimmune disease of the central nervous system, potentially leading to persistent neurological deterioration. The cause of MS is not known, and apart from immunomodulatory treatments there is no cure. In the early phase of the disease, relapsing-remitting MS (RR-MS) is characterized by unpredictable exacerbations of the neurological symptoms called relapses, which can occur at different intervals ranging from 4 weeks to several years. Microbial infections are known to be able to trigger MS relapses, and the patients are instructed to avoid all factors that might increase the risk of infections and to properly use antibiotics as well as to take care of dental hygiene. Among those environmental factors which are known to increase susceptibility to infections, high ambient air inhalable particulate matter levels affect all people within a geographical region. During the period of interest in this thesis, the occurrence of MS relapses could be effectively reduced by injections of interferon, which has immunomodulatory and antiviral properties. In this thesis, ecological and epidemiological analyses were used to study the possible connection between MS relapse occurrence, population level viral infections and air quality factors, as well as the effects of interferon medication. Hospital archive data were collected retrospectively from 1986-2001, a period in time ranging from when interferon medication first became available until just before other disease-modifying MS therapies arrived on the market. The grouped data were studied with logistic regression and intervention analysis, and individual patient data with survival analysis. Interferons proved to be effective in the treatment of MS in this observational study, as the amount of MS exacerbations was lower during interferon use as compared to the time before interferon treatment. A statistically significant temporal relationship between MS relapses and inhalable particular matter (PM10) concentrations was found in this study, which implies that MS patients are affected by the exposure to PM10. Interferon probably protected against the effect of PM10, because a significant increase in the risk of exacerbations was only observed in MS patients without interferon medication following environmental exposure to population level specific viral infections and PM10. Apart from being antiviral, interferon could thus also attenuate the enhancement of immune reactions caused by ambient air PM10. The retrospective approach utilizing carefully constructed hospital records proved to be an economical and reliable source of MS disease information for statistical analyses.

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Tämän eksploratiivisen tutkimuksen tarkoituksena on tutkia yrittäjän persoonallisuuden roolia ekologisesti suuntautuneen brändin identiteetin ja assosiaatioiden rakentamisessa. Tutkimus on tehty yrittäjän näkökulmasta, jonka kontekstina ovat pienet ja keskisuuret yritykset. Tämä tutkimus pyrkii laajentamaan ja saamaan ymmärrystä keskeisistä käsitteistä, ja samalla edistämään PK-yrityksiin liittyvää kirjallisuutta. Tämän lisäksi tutkimus tarkastelee mitä assosiaatioita ekologisesti suuntautunut brändi korostaa identiteetissään. Tutkimus suoritettiin tapaustutkimuksena. Laadullista primääridataa kerättiin teemahaastattelemalla yrittäjää, havainnoimalla yhtä case-yrityksen messuosastoa, sekä keräämällä yrittäjän persoonallisuusattribuutteja. Jotta tutkimus saavuttaisi myös datan triangulaation, sekundääristä dataa kerättiin vahvistamaan aiempaa tutkimusta. Yhtenä sekundäärilähteenä toimivat kaksi artikkelia, jotka auttoivat vahvistamaan aiemmin esiin nostetut yrittäjän persoonallisuusattribuutit. Persoonallisuusattribuutteja verrattiin case-yrityksen brändin identiteettiin, jotta yrittäjän persoonallisuuden rooli brändin identiteetin rakentamisessa saataisiin selville. Tulokset osoittivat yhteyden brändin identiteetin ja yrittäjän persoonallisuuden välillä ekologisesti suuntautuneessa case-yrityksessä. Tulokset paljastivat myös joitakin yleisiä assosiaatioita joita luodaan ja vahvistetaan brändin identiteetin eri osa-alueiden avulla.

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Our surrounding landscape is in a constantly dynamic state, but recently the rate of changes and their effects on the environment have considerably increased. In terms of the impact on nature, this development has not been entirely positive, but has rather caused a decline in valuable species, habitats, and general biodiversity. Regardless of recognizing the problem and its high importance, plans and actions of how to stop the detrimental development are largely lacking. This partly originates from a lack of genuine will, but is also due to difficulties in detecting many valuable landscape components and their consequent neglect. To support knowledge extraction, various digital environmental data sources may be of substantial help, but only if all the relevant background factors are known and the data is processed in a suitable way. This dissertation concentrates on detecting ecologically valuable landscape components by using geospatial data sources, and applies this knowledge to support spatial planning and management activities. In other words, the focus is on observing regionally valuable species, habitats, and biotopes with GIS and remote sensing data, using suitable methods for their analysis. Primary emphasis is given to the hemiboreal vegetation zone and the drastic decline in its semi-natural grasslands, which were created by a long trajectory of traditional grazing and management activities. However, the applied perspective is largely methodological, and allows for the application of the obtained results in various contexts. Models based on statistical dependencies and correlations of multiple variables, which are able to extract desired properties from a large mass of initial data, are emphasized in the dissertation. In addition, the papers included combine several data sets from different sources and dates together, with the aim of detecting a wider range of environmental characteristics, as well as pointing out their temporal dynamics. The results of the dissertation emphasise the multidimensionality and dynamics of landscapes, which need to be understood in order to be able to recognise their ecologically valuable components. This not only requires knowledge about the emergence of these components and an understanding of the used data, but also the need to focus the observations on minute details that are able to indicate the existence of fragmented and partly overlapping landscape targets. In addition, this pinpoints the fact that most of the existing classifications are too generalised as such to provide all the required details, but they can be utilized at various steps along a longer processing chain. The dissertation also emphases the importance of landscape history as an important factor, which both creates and preserves ecological values, and which sets an essential standpoint for understanding the present landscape characteristics. The obtained results are significant both in terms of preserving semi-natural grasslands, as well as general methodological development, giving support to science-based framework in order to evaluate ecological values and guide spatial planning.