51 resultados para local coefficients


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The overall purpose of this thesis was to increase the knowledge on the biogeochemistry of rural acid sulphate (AS) soil environments and urban forest ecosystems near small towns in Western Finland. In addition, the potential causal relationship between the distribution of AS soils and geographical occurence of multiple sclerosis (MS) disease was assessed based on a review of existing literature and data. Acid sulphate soils, which occupy an area of approximately 17–24 million hectare worldwide, are regarded as the nastiest soils in the world. Independent of the geographical locality of these soils, they pose a great threat to their surrounding environment if disturbed. The abundant metal-rich acid drainage from Finnish AS soils, which is a result of sulphide oxidation due to artificial farmland drainage, has significant but spatially and temporally variable ecotoxicological impacts on biodiversity and community structure of fish, benthic invertebrates and macrophytes. This has resulted in mass fish kills and even eradication of sensitive fish species in affected waters. Moreover, previous investigations demonstrated significantly enriched concentrations of Co, Ni, Mn and Al, metals which are abundantly mobilised in AS soils, in agricultural crops (timothy grass and oats) and approximately 50 times higher concentrations of Al in cow milk originating from AS soils in Western Finland. Nevertheless, the results presented here demonstrate, in general, relatively moderate metal concentrations in oats and cabbage grown on AS soils in Western Finland, although some of the studied fields showed anomalous values of metals (e.g. Co and Ni) in both the soil and target plants (especially oats), similar to that of the previous investigations. The results indicated that the concentrations of Co, Ni, Mn and Zn in oats and Co and Zn in cabbage were governed by soil geochemistry as these metals were correlated with corresponding concentrations extracted from the soil by NH4Ac-EDTA and NH4Ac, respectively. The concentrations of Cu and Fe in oats and cabbage were uncorrelated to that of the easily soluble concentrations in the soils, suggesting that biological processes (e.g. plant-root processes) overshadow geochemical variation. The concentrations of K and Mg in cabbage, which showed a low spread and were strongly correlated to the NH4Ac extractable contents in the soil, were governed by both the bioavailable fractions in the topsoil and plant-uptake mechanisms. The plant´s ability to regulate its uptake of Ca and P (e.g. through root exudates) seemed to be more important than the influence of soil geochemistry. The distribution of P, K, Ca, Mg, Mn and S within humus, moss and needles in and around small towns was to a high degree controlled by biological cycling, which was indicated by the low correlation coefficients for P, K, Ca, Mg and S between humus and moss, and the low spread of these nutrients in moss and needles. The concentration variations of elements in till are mainly due to natural processes (e.g. intrusions, weathering, mineralogical variations in the bedrock). There was a strong spatial pattern for B in humus, moss and needles, which was suggested to be associated with anthropogenic emissions from nearby town centres. Geogenic dust affected the spatial distribution of Fe and Cr in moss, while natural processes governed the Fe anomaly found in the needles. The spatial accumulation patterns of Zn, Cd, Cu, Ni and Pb in humus and moss were strong and diverse, and related to current industry, the former steel industry, coal combustion, and natural geochemical processes. An intriguing Cu anomaly was found in moss. Since it was located close to a main railway line and because the railway line´s electric cables are made of Cu, it was suggested that the reason for the Cu anomaly is corrosion of these cables. In Western Finland, where AS soils are particularly abundant and enrich the metal concentrations of stream waters, cow milk and to some extent crops, an environmental risk assessment would be motivated to elucidate if the metal dispersion affect human health. Within this context, a topic of concern is the distribution of multiple sclerosis as high MS prevalence rates are found in the main area of AS soils. Regionally, the AS soil type in the Seinäjoki area has been demonstrated to be very severe in terms of metal leaching, this area also shows one of the highest MS rates reported worldwide. On a local scale, these severe AS soil types coincide well with the corresponding MS clustering along the Kyrönjoki River in Seinäjoki. There are reasons to suspect that these spatial correlations are causal, as multiple sclerosis has been suggested to result from a combination of genetic and environmental factors.

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Webben är en enorm källa för information. Innehållet på webbsidorna är en synlig typ av information, men webben innehåller även information av en annan typ, en mera gömd typ i form av sambanden och nätverken som hyperlänkarna skapar mellan webbsajterna och –sidorna som de kopplar ihop. Forskningsområdet webometri ämnar, bland annat, att skapa ny kunskap ur denna gömda information som finns inbyggt i hyperlänkarna samt att skapa förståelse för hurudana fenomen och förhållanden utanför webben kan finnas representerade i hyperlänkarna. Målet med denna forskning var att öka förståelse för användningen av hyperlänkar på webben och speciellt kommunernas användning av hyperlänkar. Denna forskning undersökte hur kommunerna i Egentliga Finland skapade och mottog hyperlänkar samt hurudana nätverk formades av dessa hyperlänkar. Forskningen kartlade nätverk av direkta länkar mellan kommunerna och av samlänkar till och från kommunerna och undersökte ifall dessa nätverk kunde användas för att undersöka geopolitiska förhållanden och samarbete mellan kommunerna i Egentliga Finland. De övergripande forskningsfrågorna som har besvarats i denna forskning är: 1) Från ett webometriskt perspektiv, hur använder kommunerna i Egentliga Finland webben? 2) Kan hyperlänkar (direkta länkar och samlänkar) användas för att kartlägga geopolitiska förhållanden och samarbete mellan kommuner? 3) Vilka är de viktigaste motiveringarna för att skapa länkar mellan, till och från kommunernas webbsajter? Denna forskning kom till ovanligt tydliga resultat för en webometrisk forskning, både när det gäller upptäckta geografiska faktorer som påverkar hyperlänkningarna och de klassificerade motivationerna för att skapa länkarna. Resultaten visade att de direkta hyperlänkarna mellan kommunerna kan användas för att kartlägga geopolitiska förhållanden och samarbete mellan kommunerna för att de direkta länkarna var motiverade av officiella orsaker och de var klart påverkade av distansen mellan kommunerna och av de ekonomiska regionerna. Samlänkningarna in till kommunerna visade sig fungera som ett mått för geografisk likhet mellan kommunerna, medan samlänkningarna ut från kommunerna visade potential för att kunna användas till för att kartlägga kommunernas gemensamma intressen. Forskningen kontribuerade även till utvecklandet av forskningsområdet webometri. En del av de viktigaste kontributionerna av denna forskning var utvecklandet av nya metoder för webometrisk forskning samt att öka kunskap om hur existerande metoder från nätverksanalys kan användas effektivt för webometrisk forskning. Resultaten från denna forskning och de utvecklade metoderna kan användas för snabba kartläggningar av diverse förhållanden mellan olika organisationer och företag genom att använda information gratis tillgängligt på webben.

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The thesis explores global and national-level issues related to the development of markets for biomass for energy. The thesis consists of five separate papers and provides insights on selected issues. The aim of Paper I was to identify methodological and statistical challenges in assessing international solid and liquid biofuels trade and provide an overview of the Finnish situation with respect to the status of international solid and liquid biofuels trade. We found that, for the Finnish case, it is possible to qualify direct and indirect trade volumes of biofuels. The study showed that indirect trade of biofuels has a highly significant role in Finland and may be a significant sector also in global biofuels trade. The purpose of Paper II was to provide a quantified insight into Finnish prospects for meeting the national 2020 renewable energy targets and concurrently becoming a largescale producer of forest-biomass-based second-generation biofuels for feeding increasing demand in European markets. We found that Finland has good opportunities to realise a scenario to meet 2020 renewable energy targets and for large-scale production of wood-based biofuels. The potential net export of transport biofuels from Finland in 2020 would correspond to 2–3% of European demand. Paper III summarises the global status of international solid and liquid biofuels trade as illuminated by several separate sources. International trade of biofuels was estimated at nearly 1 EJ for 2006. Indirect trade of biofuels through trading of industrial roundwood and material by-products comprises the largest proportion of the trading, with a share of about two thirds. The purpose of Paper IV was to outline a comprehensive picture of the coverage of various certification schemes and sustainability principles relating to the entire value-added chain of biomass and bioenergy. Regardless of the intensive work that has been done in the field of sustainability schemes and principles concerning use of biomass for energy, weaknesses still exist. The objective of Paper V was to clarify the alternative scenarios for the international biomass market until 2020 and identify the underlying steps needed toward a wellfunctioning and sustainable market for biomass for energy purposes. An overall conclusion drawn from this analysis concerns the enormous opportunities related to the utilisation of biomass for energy in the coming decades.