12 resultados para 189-1172
em Helda - Digital Repository of University of Helsinki
Resumo:
The increase in global temperature has been attributed to increased atmospheric concentrations of greenhouse gases (GHG), mainly that of CO2. The threat of severe and complex socio-economic and ecological implications of climate change have initiated an international process that aims to reduce emissions, to increase C sinks, and to protect existing C reservoirs. The famous Kyoto protocol is an offspring of this process. The Kyoto protocol and its accords state that signatory countries need to monitor their forest C pools, and to follow the guidelines set by the IPCC in the preparation, reporting and quality assessment of the C pool change estimates. The aims of this thesis were i) to estimate the changes in carbon stocks vegetation and soil in the forests in Finnish forests from 1922 to 2004, ii) to evaluate the applied methodology by using empirical data, iii) to assess the reliability of the estimates by means of uncertainty analysis, iv) to assess the effect of forest C sinks on the reliability of the entire national GHG inventory, and finally, v) to present an application of model-based stratification to a large-scale sampling design of soil C stock changes. The applied methodology builds on the forest inventory measured data (or modelled stand data), and uses statistical modelling to predict biomasses and litter productions, as well as a dynamic soil C model to predict the decomposition of litter. The mean vegetation C sink of Finnish forests from 1922 to 2004 was 3.3 Tg C a-1, and in soil was 0.7 Tg C a-1. Soil is slowly accumulating C as a consequence of increased growing stock and unsaturated soil C stocks in relation to current detritus input to soil that is higher than in the beginning of the period. Annual estimates of vegetation and soil C stock changes fluctuated considerably during the period, were frequently opposite (e.g. vegetation was a sink but soil was a source). The inclusion of vegetation sinks into the national GHG inventory of 2003 increased its uncertainty from between -4% and 9% to ± 19% (95% CI), and further inclusion of upland mineral soils increased it to ± 24%. The uncertainties of annual sinks can be reduced most efficiently by concentrating on the quality of the model input data. Despite the decreased precision of the national GHG inventory, the inclusion of uncertain sinks improves its accuracy due to the larger sectoral coverage of the inventory. If the national soil sink estimates were prepared by repeated soil sampling of model-stratified sample plots, the uncertainties would be accounted for in the stratum formation and sample allocation. Otherwise, the increases of sampling efficiency by stratification remain smaller. The highly variable and frequently opposite annual changes in ecosystem C pools imply the importance of full ecosystem C accounting. If forest C sink estimates will be used in practice average sink estimates seem a more reasonable basis than the annual estimates. This is due to the fact that annual forest sinks vary considerably and annual estimates are uncertain, and they have severe consequences for the reliability of the total national GHG balance. The estimation of average sinks should still be based on annual or even more frequent data due to the non-linear decomposition process that is influenced by the annual climate. The methodology used in this study to predict forest C sinks can be transferred to other countries with some modifications. The ultimate verification of sink estimates should be based on comparison to empirical data, in which case the model-based stratification presented in this study can serve to improve the efficiency of the sampling design.
Resumo:
This study focuses on self-employed industrial designers and how they emerge new venture ideas. More specifically, this study strives to determine what design entrepreneurs do when they create new venture ideas, how venture ideas are nurtured into being, and how the processes are organized to bring such ideas to the market in the given industrial context. In contemporary times when the concern for the creative class is peaking, the research and business communities need more insight of the kind that this study provides, namely how professionals may contribute to their entrepreneurial processes and other agents’ business processes. On the one hand, the interviews underlying this study suggest that design entrepreneurs may act as reactive service providers who are appointed by producers or marketing parties to generate product-related ideas on their behalf. On the other hand, the interviews suggest that proactive behaviour that aims on generating own venture ideas, may force design entrepreneurs to take considerable responsibility in organizing their entrepreneurial processes. Another option is that they strive to bring venture ideas to the market in collaboration, or by passing these to other agents’ product development processes. Design entrepreneurs’ venture ideas typically emerge from design related starting points and observations. Product developers are mainly engaged with creating their own ideas, whereas service providers refer mainly to the development of other agents’ venture ideas. In contrast with design entrepreneurs, external actors commonly emphasize customer demand as their primary source for new venture ideas, as well as development of these in close interaction with available means of production and marketing. Consequently, design entrepreneurs need to address market demand since without sales their venture ideas may as well be classified as art. In case, they want to experiment with creative ideas, then there should be another source of income to support this typically uncertain and extensive process. Currently, it appears like a lot of good venture ideas and resources are being wasted, when venture ideas do not suite available production or business procedures. Sufficient communication between design entrepreneurs and other agents would assist all parties in developing production efficient and distributable venture ideas. Overall, the findings suggest that design entrepreneurs are often involved simultaneously in several processes that aim at emerging new product related ventures. Consequently, design entrepreneurship is conceptualized in this study as a dual process. This implies that design entrepreneurs can simultaneously be in charge of their entrepreneurial processes, as they operate as resources in other agents’ business processes. The interconnection between activities and agents suggests that these kinds of processes tend to be both complex and multifaceted to their nature.
Resumo:
Inspired by the recent debate in the financial press, we set out to investigate if financial analysts warn their preferred customers of possible earnings forecast revisions. The issue is explored by monitoring investors’ trading behavior during the weeks prior to analyst earnings forecast revisions, using the unique official stock transactions data set from Finland. In summary, we do not find evidence of large investors systematically being warned of earnings forecast revisions. However, the results indicate that the very largest investors show trading behavior partly consistent with being informed of future earnings forecast revisions.
Resumo:
Tutkimuksessa tarkastellaan dementiakuolleisuutta sekä siihen vaikuttavia sosiaalisia tekijöitä. Dementia on oireyhtymä, jota pääasiassa sairastavat yli 65 -vuotiaat henkilöt. Väestön ikääntyessä sekä elinajanodotteen kasvaessa on odotettavissa, että dementiaa sairastavien määrä tulee kasvamaan merkittävästi lähivuosina. On viitteitä siitä, että dementiaan sairastumisen riskiin vaikuttavat erilaiset sosiaaliset tekijät kuten koulutus, mutta varsinkin dementiakuolleisuudesta tiedetään vähän. Tutkielman aineistona käytettiin Tilastokeskuksen muodostamaa Elinolot ja kuolinsyyt -rekisteriaineistoa, joka koostuu väestölaskentatiedoista sekä työssäkäyntitilaston pitkittäisaineistosta, johon on liitetty kuolinsyytietoja. Peruskuolinsyyn lisäksi aineistossa oli tieto korkeintaan kolmesta myötävaikuttavasta syystä. Dementiakuolleisuuden on esitetty aliarvioituvan peruskuolinsyynä, joten dementiakuolleisuuden määrittelyssä käytettiin myös tietoa myötävaikuttavista syistä. Rajausten jälkeen aineistossa on 317 944 henkilöä, joista 128 562 on miehiä ja 189 382 naisia. Pääanalyysimenetelmänä on käytetty elinaikamalleihin kuuluvaa Coxin regressiota. Dementiakuolleisuudessa oli vaihtelua kaikkien tutkimuksessa käytettyjen muuttujien, eli koulutuksen, sosiaaliluokan, tulojen, siviilisäädyn sekä perhemuodon mukaan. Koulutuksen vaikutus välittyi osin ammattiasemaan perustuvan sosiaaliluokan kautta. Suurimpia ryhmien väliset suhteelliset erot olivat nuoremmissa ikäryhmissä sekä sosiaaliluokan ja siviilisäädyn kohdalla. Eronneilla ja naimattomilla oli selvästi kohonnut riski suhteessa naimisissa oleviin. Myös työntekijöillä havaittiin kohonnut riski suhteessa ylempiin toimihenkilöihin. Siviilisääty vaikutti olevan merkittävä tekijä siinä mielessä, että koulutuksen, sosiaaliluokan ja tulojen tuominen malliin ei juuri vaikuttanut siviilisäätyryhmien välillä havaittuun vaihteluun. Dementiakuolleisuudessa havaitut ryhmien väliset suhteelliset erot olivat hieman pienempiä kuin muissa syissä, mutta kuitenkin hyvin samaa suuruusluokkaa. Tulosten perusteella on identifioitavissa tekijöitä, jotka suojaavat dementialta. Erityisesti avioliitto, korkea koulutus sekä ylemmät toimihenkilöammatit vaikuttavat olevan dementialta suojaavia tekijöitä. Avioliiton suojaavan vaikutuksen voidaan tulkita liittyvän sosiaaliseen kanssakäymiseen sekä puolison tukeen ja läsnäoloon. Korkea koulutus sekä toimihenkilöammatit indikoivat virikkeellisempää työympäristöä, mutta niiden vaikutus voi myös kulkea ylipäänsä aktiivisemman ja kognitiivisesti virikkeellisemmän elämäntavan kautta. Aktiivisen ja kognitiivisesti haastavan elämäntavan on esitetty suojaavan dementiaan sairastumiselta. Tuloksia voidaan tulkita elämänkaarinäkökulman kautta. Jo nuoruudessa vaikuttavilla tekijöillä, kuten koulutuksella, on vaikutusta. Tämän lisäksi elämänkaaren aikana myöhemmin vaikuttavat tekijät ovat merkityksellisiä. Näiden tekijöiden on esitetty vaikuttavan aivojen hermoverkostoon ja -yhteyksiin ja luovan kognitiivista reserviä, minkä on esitetty ehkäisevän tai lykkäävän dementiaan sairastumista.
Resumo:
The Baltic Sea is one of the most eutrophic marine areas in the world. The role of nitrogen as a eutrophicating nutrient in the Baltic Sea has remained controversial, due to lack of understanding of nitrogen cycling in the area. We investigated the seasonal variation in sediment nitrification, denitrification, anaerobic ammonium oxidation (anammox), and dissimilatory nitrate reduction to ammonium (DNRA) at two coastal sites in the Gulf of Finland. In addition to the in situ rates, we assessed the potential for these processes in different seasons. The nitrification and nitrogen removal processes were maximal during the warm summer months, when the sediment organic content was highest. In colder seasons, the in situ rates of the nitrification and nitrate reduction processes decreased, but the potential for nitrification remained equal to or higher than that during the warm months. The denitrification and nitrification rates were usually higher in the accumulation basin, where the organic content of the sediment was higher, but the transportation area, despite lower denitrification rates and potential, typically had higher potential for nitrification than the accumulation basin. Anammox and DNRA were not significant nitrate sinks in any of the seasons sampled. The results also show that the denitrification rates in the coastal Gulf of Finland sediment have decreased, and that benthic denitrification might be a less important sink for fixed nitrogen than previously assumed.
Resumo:
Right as an Argument. Leo Mechelin and the Finnish Question 1886-1912 At the turn of the 20th century the Finnish Question rose up as a political and juridical issue at the international arena. The vaguely précised position of Finland in the Russian empire led to diverse conclusions concerning the correctness of the February manifesto of 1899. It was predominantly among a European elite of politicians, cultural workers and academics the issue rose some interest. Finns were active making propaganda for their cause, and they put an emphasis on the claim that the right was on the Finnish side. In the study Elisabeth Stubb compare the Finnish, Russian and European statements about the Finnish Question and analyse their use of right as an argument. The Finnish Question offers at the same time a case study of a national entity which possesses a political sphere of life but is not fully independent, and its possibilities to drive its interests in an international context. Leo Mechelin (1839-1914), the leader of the Finnish propaganda organization abroad, is used as a point of departure. The biographical stance is formed into a triangle, where Leo Mechelin, the idea of right and the Finnish Question abroad are the three cornerstones. The treatment of one cornerstone sheds a ligth on the two others. The metaphor of triangulation also worked as a method to reach "a third stance" in a scinetific and political issue that usually is polarised into two opposite alternatives. An adherence to a strict legal right could not in the end offer a complete, unquestionable and satisfactory solution to the Finnsih Question, it was dependent on "the right of state wisdom and sound insight". The Finnish propaganda abroad used almost completely alternative ways of making politics. The propaganda did not have a decisive effect on countries' official politics, but gained unofficial support, especially in the public opinion and in academic statements. Mechelin claimed that the political field was dependent on public opinion and scientific research. Together with the official politics these two fields formed a triangle that shared the task of balancing the political arena and preventing it from making unwise decisions of taking an unjust turn. The international sphere worked as a balancing part in the Finnish Question. Mechelin tried by claiming the status of state for Finland's part to secure the country a place at the official international arena. At the same time, and especially when the claim was not fully adopted, he emphasised, and in a European context worked for, that right would become the guiding light not only for international relations, but also for the policy making in the inner life of the state.
Resumo:
Abstract. Peat surface CO2 emission, groundwater table depth and peat temperature were monitored for two years along transects in an Acacia plantation on thick tropical peat (>4 m) in Sumatra, Indonesia. A total of 2300 emission measurements were taken at 144 locations. The autotrophic root respiration component of the CO2 emission was separated from heterotrophic emissions caused by peat oxidation in three ways: (i) by comparing CO2 emissions within and beyond the tree rooting zone, (ii) by comparing CO2 emissions with and without peat trenching (i.e. cutting any roots remaining in the peat beyond the tree rooting zone), and (iii) by comparing CO2 emissions before and after Acacia tree harvesting. On average, the contribution of root respiration to daytime CO2 emission is 21 % along transects in mature tree stands. At locations 0.5 m from trees this is up to 80 % of the total emissions, but it is negligible at locations more than 1.3 m away. This means that CO2 emission measurements well away from trees are free of any root respiration contribution and thus represent only peat oxidation emission. We find daytime mean annual CO2 emission from peat oxidation alone of 94 t ha−1 yr−1 at a mean water table depth of 0.8 m, and a minimum emission value of 80 t ha−1 yr−1 after correction for the effect of diurnal temperature fluctuations, which resulted in a 14.5 % reduction of the daytime emission. There is a positive correlation between mean long-term water table depths and peat oxidation CO2 emission. However, no such relation is found for instantaneous emission/water table depth within transects and it is clear that factors other than water table depth also affect peat oxidation and total CO2 emissions. The increase in the temperature of the surface peat due to plantation development may explain over 50 % of peat oxidation emissions.
Resumo:
Abstract. Methane emissions from natural wetlands and rice paddies constitute a large proportion of atmospheric methane, but the magnitude and year-to-year variation of these methane sources is still unpredictable. Here we describe and evaluate the integration of a methane biogeochemical model (CLM4Me; Riley et al., 2011) into the Community Land Model 4.0 (CLM4CN) in order to better explain spatial and temporal variations in methane emissions. We test new functions for soil pH and redox potential that impact microbial methane production in soils. We also constrain aerenchyma in plants in always-inundated areas in order to better represent wetland vegetation. Satellite inundated fraction is explicitly prescribed in the model because there are large differences between simulated fractional inundation and satellite observations. A rice paddy module is also incorporated into the model, where the fraction of land used for rice production is explicitly prescribed. The model is evaluated at the site level with vegetation cover and water table prescribed from measurements. Explicit site level evaluations of simulated methane emissions are quite different than evaluating the grid cell averaged emissions against available measurements. Using a baseline set of parameter values, our model-estimated average global wetland emissions for the period 1993–2004 were 256 Tg CH4 yr−1, and rice paddy emissions in the year 2000 were 42 Tg CH4 yr−1. Tropical wetlands contributed 201 Tg CH4 yr−1, or 78 % of the global wetland flux. Northern latitude (>50 N) systems contributed 12 Tg CH4 yr−1. We expect this latter number may be an underestimate due to the low high-latitude inundated area captured by satellites and unrealistically low high-latitude productivity and soil carbon predicted by CLM4. Sensitivity analysis showed a large range (150–346 Tg CH4 yr−1) in predicted global methane emissions. The large range was sensitive to: (1) the amount of methane transported through aerenchyma, (2) soil pH (± 100 Tg CH4 yr−1), and (3) redox inhibition (± 45 Tg CH4 yr−1).