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  • Alenius, Teija (Helsingin yliopisto, 2007)
    This thesis discusses the prehistoric human disturbance during the Holocene by means of case studies using detailed high-resolution pollen analysis from lake sediment. The four lakes studied are situated between 61o 40' and 61o 50' latitudes in the Finnish Karelian inland area and vary between 2.4 and 28.8 ha in size. The existence of Early Metal Age population was one important question. Another study question concerned the development of grazing, and the relationship between slash-and-burn cultivation and permanent field cultivation. The results were presented as pollen percentages and pollen concentrations (grains cm 3). Accumulation values (grains cm 2 yr 1) were calculated for Lake Nautajärvi and Lake Orijärvi sediment, where the sediment accumulation rate was precisely determined. Sediment properties were determined using loss-on-ignition (LOI) and magnetic susceptibility (k). Dating methods used include both conventional and AMS 14C determinations, paleomagnetic dating and varve choronology. The isolation of Lake Kirjavalampi on the northern shore of Lake Ladoga took place ca. 1460 1300 BC. The long sediment cores from Finland, Lake Kirkkolampi and Lake Orijärvi in southeastern Finland and Lake Nautajärvi in south central Finland all extended back to the Early Holocene and were isolated from the Baltic basin ca. 9600 BC, 8600 BC and 7675 BC, respectively. In the long sediment cores, the expansion of Alnus was visible between 7200 - 6840 BC. The spread of Tilia was dated in Lake Kirkkolampi to 6600 BC, in Lake Orijärvi to 5000 BC and at Lake Nautajärvi to 4600 BC. Picea is present locally in Lake Kirkkolampi from 4340 BC, in Lake Orijärvi from 6520 BC and in Lake Nautajärvi from 3500 BC onwards. The first modifications in the pollen data, apparently connected to anthropogenic impacts, were dated to the beginning of the Early Metal Period, 1880 1600 BC. Anthropogenic activity became clear in all the study sites by the end of the Early Metal Period, between 500 BC AD 300. According to Secale pollen, slash-and-burn cultivation was practised around the eastern study lakes from AD 300 600 onwards, and at the study site in central Finland from AD 880 onwards. The overall human impact, however, remained low in the studied sites until the Late Iron Age. Increasing human activity, including an increase in fire frequency was detected from AD 800 900 onwards in the study sites in eastern Finland. In Lake Kirkkolampi, this included cultivation on permanent fields, but in Lake Orijärvi, permanent field cultivation became visible as late as AD 1220, even when the macrofossil data demonstrated the onset of cultivation on permanent fields as early as the 7th century AD. On the northern shore of Lake Ladoga, local activity became visible from ca. AD 1260 onwards and at Lake Nautajärvi, sediment the local occupation was traceable from 1420 AD onwards. The highest values of Secale pollen were recorded both in Lake Orijärvi and Lake Kirjavalampi between ca. AD 1700 1900, and could be associated with the most intensive period of slash-and-burn from AD 1750 to 1850 in eastern Finland.
  • Kouki, Paula (Helsingin yliopisto, 2006)
    The research is related to the Finnish Jabal Harun Project (FJHP), which is part of the research unit directed by Professor Jaakko Frösén. The project consists of two interrelated parts: the excavation of a Byzantine monastery/pilgrimage centre on Jabal Harun, and a multiperiod archaeological survey of the surrounding landscape. It is generally held that the Near Eastern landscape has been modified by millennia of human habitation and activity. Past climatic changes and human activities could be expected to have significantly changed also the landscape of the Jabal Harun area. Therefore it was considered that a study of erosion in the Jabal Harun area could shed light on the environmental and human history of the area. It was hoped that it would be possible to connect the results of the sedimentological studies either to wider climatic changes in the Near East, or to archaeologically observable periods of human activity and land use. As evidence of some archaeological periods is completely missing from the Jabal Harun area, it was also of interest whether catastrophic erosion or unfavourable environmental change, caused either by natural forces or by human agency, could explain the gaps in the archaeological record. Changes in climate and/or land-use were expected to be reflected in the sedimentary record. The field research, carried out as part of the FJHP survey fieldwork, included the mapping of wadi terraces and cleaning of sediment profiles which were recorded and sampled for laboratory analyses of facies and lithology. To obtain a chronology for the sedimentation and erosion phases also OSL (optically stimulated luminescence) dating samples were collected. The results were compared to the record of the Near Eastern palaeoclimate, and to data from geoarchaeological studies in central and southern Jordan. The picture of the environmental development was then compared to the human history in the area, based on archaeological evidence from the FJHP survey and the published archaeological research in the Petra region, and the question of the relationship between human activity and environmental change was critically discussed. Using the palaeoclimatic data and the results from geoarchaeological studies it was possible to outline the environmental development in the Jabal Harun area from the Pleistocene to the present.It is appears that there was a phase of accumulation of sediment before the Middle Palaeolithic period, possibly related to tectonic movement. This phase was later followed by erosion, tentatively suggested to have taken place during the Upper Palaeolithic. A period of wadi aggradation probably occurred during the Late Glacial and continued until the end of the Pleistocene, followed by significant channel degradation, attributed to increased rainfall during the Early Holocene. It seems that during the later Holocene channel incision has been dominant in the Jabal Harûn area although there have been also small-scale channel aggradation phases, two of which were OSL-dated to around 4000-3000 BP and 2400-2000 BP. As there is no evidence of tectonic movements in the Jabal Harun area after the early Pleistocene, it is suggested that climate change and human activity have been the major causes of environmental change in the area. At a brief glance it seems that many of the changes in the settlement and land use in the Jabal Harun area can be explained by climatic and environmental conditions. However, the responses of human societies to environmental change are dependent on many factors. Therefore an evaluation of the significance of environmental, cultural, socio-economic and political factors is needed to decide whether certain phenomena are environmentally induced. Comparison with the wider Petra region is also needed to judge whether the phenomena are characteristic of the Jabal Harun area only, or can they be connected to social, political and economic development over a wider area.
  • Ilus, Erkki (Helsingin yliopisto, 2009)
    During recent decades, thermal and radioactive discharges from nuclear power plants into the aquatic environment have become the subject of lively debate as an ecological concern. The target of this thesis was to summarize the large quantity of results obtained in extensive monitoring programmes and studies carried out in recipient sea areas off the Finnish nuclear power plants at Loviisa and Olkiluoto during more than four decades. The Loviisa NPP is located on the coast of the Gulf of Finland and Olkiluoto NPP on that of the Bothnian Sea. The state of the Gulf of Finland is clearly more eutrophic; the nutrient concentrations in the surface water are about 1½ 2 times higher at Loviisa than at Olkiluoto, and the total phosphorus concentrations still increased in both areas (even doubled at Loviisa) between the early 1970s and 2000. Thus, it is a challenge to distinguish the local effects of thermal discharges from the general eutrophication process of the Gulf of Finland. The salinity is generally low in the brackish-water conditions of the northern Baltic Sea, being however about 1 higher at Olkiluoto than at Loviisa (the salinity of surface water varying at the latter from near to 0 in early spring to 4 6 in late autumn). Thus, many marine and fresh-water organisms live in the Loviisa area close to their limit of existence, which makes the biota sensitive to any additional stress. The characteristics of the discharge areas of the two sites differ from each other in many respects: the discharge area at Loviisa is a semi-enclosed bay in the inner archipelago, where the exchange of water is limited, while the discharge area at Olkiluoto is more open, and the exchange of water with the open Bothnian Sea is more effective. The effects of the cooling water discharged from the power plants on the temperatures in the sea were most obvious in winter. The formation of a permanent ice cover in the discharge areas has been delayed in early winter, and the break-up of the ice occurs earlier in spring. The prolonging of the growing season and the disturbance of the overwintering time, in conditions where the biota has adjusted to a distinct rest period in winter, have been the most significant biological effects of the thermal pollution. The soft-bottom macrofauna at Loviisa has deteriorated to the point of almost total extinction at many sampling stations during the past 40 years. A similar decline has been reported for the whole eastern Gulf of Finland. However, the local eutrophication process seems to have contributed into the decline of the zoobenthos in the discharge area at Loviisa. Thermal discharges have increased the production of organic matter, which again has led to more organic bottom deposits. These have in turn increased the tendency of the isolated deeps to a depletion of oxygen, and this has further caused strong remobilization of phosphorus from the bottom sediments. Phytoplankton primary production and primary production capacity doubled in the whole area between the late 1960s and the late 1990s, but started to decrease a little at the beginning of this century. The focus of the production shifted from spring to mid- and late summer. The general rise in the level of primary production was mainly due to the increase in nutrient concentrations over the whole Gulf of Finland, but the thermal discharge contributed to a stronger increase of production in the discharge area compared to that in the intake area. The eutrophication of littoral vegetation in the discharge area has been the most obvious, unambiguous and significant biological effect of the heated water. Myriophyllum spicatum, Potamogeton perfoliatus and Potamogeton pectinatus, and vigorous growths of numerous filamentous algae as their epiphytes have strongly increased in the vicinity of the cooling water outlet, where they have formed dense populations in the littoral zone in late summer. However, the strongest increase of phytobenthos has extended only to a distance of about 1 km from the outlet, i.e., the changes in vegetation have been largest in those areas that remain ice-free in winter. Similar trends were also discernible at Olkiluoto, but to a clearly smaller extent, which was due to the definitely weaker level of background eutrophy and nutrient concentrations in the Bothnian Sea, and the differing local hydrographical and biological factors prevailing in the Olkiluoto area. The level of primary production has also increased at Olkiluoto, but has remained at a clearly lower level than at Loviisa. In spite of the analogous changes observed in the macrozoobenthos, the benthic fauna has remained strong and diversified in the Olkiluoto area. Small amounts of local discharge nuclides were regularly detected in environmental samples taken from the discharge areas: tritium in seawater samples, and activation products, such as 60Co, 58Co, 54Mn, 110mAg, 51Cr, in suspended particulate matter, bottom sediments and in several indicator organisms (e.g., periphyton and Fucus vesiculosus) that effectively accumulate radioactive substances from the medium. The tritium discharges and the consequent detection frequency and concentrations of tritium in seawater were higher at Loviisa, but the concentrations of the activation products were higher at Olkiluoto, where traces of local discharge nuclides were also observed over a clearly wider area, due to the better exchange of water than at Loviisa, where local discharge nuclides were only detected outside Hästholmsfjärden Bay quite rarely and in smaller amounts. At the farthest, an insignificant trace amount (0.2 Bq kg-1 d.w.) of 60Co originating from Olkiluoto was detected in Fucus at a distance of 137 km from the power plant. Discharge nuclides from the local nuclear power plants were almost exclusively detected at the lower trophic levels of the ecosystems. Traces of local discharge nuclides were very seldom detected in fish, and even then only in very low quantities. As a consequence of the reduced discharges, the concentrations of local discharge nuclides in the environment have decreased noticeably in recent years at both Loviisa and Olkiluoto. Although the concentrations in environmental samples, and above all, the discharge data, are presented as seemingly large numbers, the radiation doses caused by them to the population and to the biota are very low, practically insignificant. The effects of the thermal discharges have been more significant, at least to the wildlife in the discharge areas of the cooling water, although the area of impact has been relatively small. The results show that the nutrient level and the exchange of water in the discharge area of a nuclear power plant are of crucial importance.
  • Hjort, Jan (Helsingin yliopisto, 2006)
    Determination of the environmental factors controlling earth surface processes and landform patterns is one of the central themes in physical geography. However, the identification of the main drivers of the geomorphological phenomena is often challenging. Novel spatial analysis and modelling methods could provide new insights into the process-environment relationships. The objective of this research was to map and quantitatively analyse the occurrence of cryogenic phenomena in subarctic Finland. More precisely, utilising a grid-based approach the distribution and abundance of periglacial landforms were modelled to identify important landscape scale environmental factors. The study was performed using a comprehensive empirical data set of periglacial landforms from an area of 600 km2 at a 25-ha resolution. The utilised statistical methods were generalized linear modelling (GLM) and hierarchical partitioning (HP). GLMs were used to produce distribution and abundance models and HP to reveal independently the most likely causal variables. The GLM models were assessed utilising statistical evaluation measures, prediction maps, field observations and the results of HP analyses. A total of 40 different landform types and subtypes were identified. Topographical, soil property and vegetation variables were the primary correlates for the occurrence and cover of active periglacial landforms on the landscape scale. In the model evaluation, most of the GLMs were shown to be robust although the explanation power, prediction ability as well as the selected explanatory variables varied between the models. The great potential of the combination of a spatial grid system, terrain data and novel statistical techniques to map the occurrence of periglacial landforms was demonstrated in this study. GLM proved to be a useful modelling framework for testing the shapes of the response functions and significances of the environmental variables and the HP method helped to make better deductions of the important factors of earth surface processes. Hence, the numerical approach presented in this study can be a useful addition to the current range of techniques available to researchers to map and monitor different geographical phenomena.
  • Uusitalo, Laura (Helsingin yliopisto, 2007)
    The Baltic Sea is a geologically young, large brackish water basin, and few of the species living there have fully adapted to its special conditions. Many of the species live on the edge of their distribution range in terms of one or more environmental variables such as salinity or temperature. Environmental fluctuations are know to cause fluctuations in populations abundance, and this effect is especially strong near the edges of the distribution range, where even small changes in an environmental variable can be critical to the success of a species. This thesis examines which environmental factors are the most important in relation to the success of various commercially exploited fish species in the northern Baltic Sea. It also examines the uncertainties related to fish stocks current and potential status as well as to their relationship with their environment. The aim is to quantify the uncertainties related to fisheries and environmental management, to find potential management strategies that can be used to reduce uncertainty in management results and to develop methodology related to uncertainty estimation in natural resources management. Bayesian statistical methods are utilized due to their ability to treat uncertainty explicitly in all parts of the statistical model. The results show that uncertainty about important parameters of even the most intensively studied fish species such as salmon (Salmo salar L.) and Baltic herring (Clupea harengus membras L.) is large. On the other hand, management approaches that reduce uncertainty can be found. These include utilising information about ecological similarity of fish stocks and species, and using management variables that are directly related to stock parameters that can be measured easily and without extrapolations or assumptions.
  • Keskitalo, Antti (2009)
    This study was carried out to evaluate environmental impacts of greenhouse tomato production in Finland. Due to the Nordic location of the country, weather conditions do not favor it and production is very energy intensive. Emissions per 1000 kg per produced tomato was selected as functional unit. Two different production methods were selected for the study. 1. Conventional production, what is based on utilization of natural light and for production break during a coldest and darkest part of a year (November-February). 2. Year-round production, which is based on an use of artificial lightning. For information of inputs and outputs, the entrepreneurs of six different greenhouse companies, which produced only tomatoes, were interviewed. Three of them were year-round producers and three of them conventional producers. Average yields were 59,0 and 28,2 kg/m2/y respectively. All the selected three conventional producers used bio-energy for heat production. Data from interviewed companies included emissions of all the inputs, e.g. use of fuels, electricity, fertilizers, transportation and packaging material. Data from Statistical Centre of Finland (TIKE) were also used. Processed data included 16 yearround producers and 165 conventional producers, which produced only tomatoes. Average yields were 52,5 and 33,1 kg/m2/y respectively. Data included only fuel and electricity use. However, a proportion of emissions of fuel and electricity use of total emissions was more than 99 % (Interviewed conventional producers). Impacts of Finnish greenhouse tomato production on Climate change, Tropospheric ozone, Eutrophication and Acidification were calculated. Due to the very intensive energy use, based mainly on burning fossil fuels like heavy fuel oil (66%) significant CO2-emissions are caused. CO2- equivalent emissions from interviewed year-round and conventional companies and from Yearround and conventional TIKE companies were 5115, 512, 6514, and 4614 kg CO2-eq per 1000 kg of tomato respectively. There were low emissions (512 kg CO2-eq per 1000 kg of tomato) from interviewed conventional companies. The low figure is due to the use of bio-energy to provide needed heat for production. Therefore use of bio-energy is a possibility to reduce significantly emissions of Finnish greenhouse tomato production.
  • Ylivainio, Kari (2009)
    The low solubility of iron (Fe) depresses plant growth in calcareous soils. In order to improve Fe availability, calcareous soils are treated with synthetic ligands, such as ethylenediaminetetraacetic acid (EDTA) and ethylenediimi-nobis(2-hydroxyphenyl)acetic acid (EDDHA). However, high expenses may hinder their use (EDDHA), and the recalcitrance of EDTA against biodegra-dation may increase the potential of cadmium (Cd) and lead (Pb) leaching. This study evaluated the ability of biodegradable ligands, i.e. different stereo-isomers of ethylenediaminedisuccinic acid (EDDS), to provide Fe for lettuce (Lactuca sativa L.) and ryegrass (Lolium perenne cv. Prego), their effects on uptake of other elements and solubility in soils and their subsequent effects on the activity of oxygen-scavenging enzymes in lettuce. Both EDTA and EDDHA were used as reference ligands. In unlimed and limed quartz sand both FeEDDS(S,S) and a mixture of stereo-isomers of FeEDDS (25% [S,S]-EDDS, 25% [R,R]-EDDS and 50% [S,R]/[R,S]-EDDS), FeEDDS(mix), were as efficient as FeEDTA and FeEDDHA in providing lettuce with Fe. However, in calcareous soils only FeEDDS(mix) was comparable to FeEDDHA when Fe was applied twice a week to mimic drip irrigation. The Fe deficiency increased the manganese (Mn) concentration in lettuce in both acidic and alkaline growth media, whereas Fe chelates depressed it. The same was observed with zinc (Zn) and copper (Cu) in acidic growth media. EDDHA probably affected the hormonal status of lettuce as well and thus depressed the uptake of Zn and Mn even more. The nutrient concentrations of ryegrass were only slightly affected by the Fe availability. After Fe chelate splitting in calcareous soils, EDDS and EDTA increased the solubility of Zn and Cu most, but only the Zn concentration was increased in lettuce. The availability of Fe increased the activity of oxygen-scavenging enzymes (ascorbate peroxidase, guaiacol peroxidase, catalase). The activity of Cu/ZnSOD (Cu/Zn superoxide dismutase) and MnSOD in lettuce leaves followed the concentrations of Zn and Mn. In acidic quartz sand low avail-ability of Fe increased the cobalt (Co) and nickel (Ni) concentrations in let-tuce, but Fe chelates decreased them. EDTA increased the solubility of Cd and Pb in calcareous soils, but not their uptake. The biodegradation of EDDS was not affected by the complexed element, and [S,S]-EDDS was biodegraded within 28 days in calcareous soils. EDDS(mix) was more recalcitrant, and after 56 days of incubation water-soluble elements (Fe, Mn, Zn, Cu, Co, Ni, Cd and Pb) corresponded to 10% of the added EDDS(mix) concentration.
  • Perttula, Sini (2012)
    The green markets are growing all the time and many different environmental performance measures (EPMs) such as forest certificates, eco-labels, footprint calculations and environmental management systems have emerged in the past few decades. These measures help companies to prove the origin of wood and the environmental friendliness of their products and production processes. This qualitative study examined how Finnish wood products companies use different environmental performance measures in both supply and demand side of the wood products market and the practices and problems related to environmental communication. Seventeen personal interviews among Finnish wood products value chain professionals were conducted in order to find the industry perspectives on the development needs in environmental performance of the wood products. The results of this study indicate that the most commonly used environmental performance measures in Finnish wood product companies are forest certificate PEFC and the standard of ISO14001. In contrast, the use of other ecolabels as well as Life Cycle Assessment methods (LCA) and related tools were relatively uncommon. The main drivers for use of EPMs were customer requirements (especially in certain environmentally sensitive export markets) and strategic decisions to act responsibly. The most important issue in environmental performance measures was perceived to be the ability to document trustworthiness of company operations. Also the origin of wood was recognized as an important issue. It also seems that forest certificates and ISO14001 standard are more important in the export markets than in the domestic markets. The supply chains for wood products are often long and complex and therefore the environmental information of the products does not always reach the end-consumers. The communication between wood product companies in the B2B markets is mainly based on personal relationships. Environmental issues are mentioned, but in most of the companies, they are still in passive use. Companies that want to stand out in the future need to start focusing on new green strategies and providing more detailed environmental information on their products and processes.
  • Kurusiov, Andrej (2008)
    This theoretical work is largely based on two papers on international tax harmonization, environmental taxation and tax competition. In particular, the papers "Agglomeration, integration and tax harmonisation" (Baldwin, R. E., Krugman, P., 2004) and "Environmental taxation, tax competition, and harmonization" (Cremer, H., Gahvari, F., 2004) are used to support each other and to follow the logic of the thesis. The structure of present work is based on analysis of the above mentioned literature, thus, dividing it into major parts: the first part is devoted to issues of integration and tax harmonization and the second part extends the discussion to the issues of environmental taxation. The first part explores the issue of whether closer economic integration necessitates harmonization of tax rates among the countries. In this part I analyze the impact of tax harmonization policies, economies agglomeration as well as goods and market integration on international tax competition. The basic tax competition model is used in exploring the effects of agglomeration forces. Further, in this paper I demonstrate that greater economic integration triggers the raise of taxes (referred as 'race to the top'). In addition, 'split the difference' tax harmonization, which basically means agreeing on a tax level that is in between two positions can make both countries worse off, because without it one region can actually set a higher tax rate without having the capital depreciation and thus not to loose a potential tax revenue. This explains why tax harmonization is very rare in the real world. Consequently, the general conclusion is that agglomeration assumptions produce reverse propositions compared to standard tax competition literature. More specifically, the explanation of rare practical implementation of tax harmonization is also that an industrial concentration creates so-called 'agglomeration rent'. The 'core' region can this way set a higher tax rate without having the capital depreciation. Thus, the first part on my thesis analyzes and demonstrates the impact of agglomeration forces on tax harmonization. Second major part of the thesis addresses tax competition problem in the context of transboundary pollution. In particular, I analyze how effective are the policies of partial fiscal coordination. Economic integration is forcing companies to adopt the same or less polluting technologies. This unfortunately results in an increase of aggregate emissions and a decline of welfare. Without proper (partial) tax harmonization policies there is an obvious negative aspect of an economic integration. Additionally, in the second part I examine partial tax harmonization policies. With a higher tax, companies choose less polluting technologies, resulting in a decrease of aggregate emissions and the improvement of welfare. Alternatively, if an emission tax is decreased, companies tend to choose more polluting (cheaper) technologies and aggregate emissions will consequently increase and welfare will deteriorate. Finally, harmonization of emission taxes above their Nash equilibrium values causes aggregate emissions to decline and overall welfare to increase. In the present work I address the issues of international tax competition from different perspectives. Thus, as a result of extensive analysis of various factors influencing international tax competition and environmental protection my main conclusion is that a closer economic integration can positively influence the environment and overall welfare.
  • Rytsölä, Perttu (2005)
    Tutkimuksen kohteena on Argentiinan vuoden 1978 jalkapallon maailmanmestaruuskilpailuiden aikainen yhteiskunta. Tutkimuksella on kaksi tavoitetta. Ensimmäinen tavoite on tarkastella kysymystä miksi Argentiinaa 1976–1982 hallinnut sotilasvalta järjesti maailmanmestaruuskilpailut. Vastaus annetaan sijoittamalla sotilasvallan toiminnasta tehtyä tutkimusta nationalismitutkimuksen ja Argentiinan yhteiskunnan viitekehykseen. Tutkimuksessa sovelletaan Michael Billigin kehittämää termiä banaali nationalismi. Banaalia nationalismia ovat arkipäiväiset yhteiskuntaa ylläpitävät toiminnot, kuten huippu-urheilu. Urheilujournalismi tarjoaa kansalaisille mahdollisuuden harjoittaa nationalistisia tunteitaan huippu-urheiluun. Sotilasvallan motiiveiksi nimetään sisäpoliittisesti rakenteellinen taistelu hegemoniasta ja ulkopoliittisesti maan ulkoisen kuvan parantaminen. Toinen tavoite on tarkastella kilpailujen ajan Argentiinan yhteiskunnallisesta tilanteesta välittynyttä lehdistökuvaa. Analyysin taustaksi tarkastellaan Argentiinan sotilasvallan ja median suhdetta. Tutkimusmenetelmänä käytetään kriittistä diskurssianalyysiä. Aineistosta nostetaan esiin teemoja, jotka johdetaan laajempiin diskursseihin. Johtopäätöksiä tarkastellaan nationalismitutkimuksen viitekehyksessä. Lehdistölähteinä käytetään argentiinalaista Clarín Edicion Internacional -julkaisua ajalta 16.5–3.7.1978 sekä Helsingin Sanomia ja brittiläistä The Times sanomalehteä ajalta 15.5–30.6.1978. Clarin Edicion Internacionalin uutisoinnista erotetaan ylpeysteema. Ylpeys viittaa muutoksen diskurssiin. Muutosta edeltää negatiivinen, ristiriitainen yhteiskunta. Maailmanmestaruuskilpailuiden aika on muutostilaa. Muutos tapahtuu argentiinalaisten oman toiminnan ansiosta. Tuloksena on positiviinen, yhtenäinen kansakunta. The Timesin uutisoinnista erotetaan kaksi kilpailevaa teemaa: Turvallisuusteema ja kisateema. Turvallisuusteema viittaa negatiiviseen diskurssiin: Argentiinan sisäisiin ristiriitoihin. Kisateema viittaa positiiviseen diskurssiin: Argentiinalaisten yhtenäisyyteen. Ajanjaksolla diskurssien suhteissa tapahtuu muutos. Alussa heikompi yhtenäisyys alistaa ristiriidat. Helsingin Sanomien uutisoinnista erotetaan kriittinen teema ja kannustusteema. Kriittinen teema viittaa negatiiviseen diskurssiin: Maata hallitsevaan sotilasvaltaan. Kannustusteema viittaa positiviiseen diskurssiin: Argentiinalaisten yhtenäisyyteen. Ajanjakson edetessä kannustusteema liittyy sotilasvaltadiskurssiin. Analyysissä tehtyjä johtopäätöksiä verrataan sotilasvallan maailmanmestaruuskilpailuille antamiin tavoitteisiin. Clarín Edicion Internacionalin ja The Timesin uutisoinnin perusteella sotilasvallan tavoitteet täyttyivät. Helsingin Sanomien uutisoinnin perusteella sotilasvalta ei onnistunut tavoitteissaan. Mediavälineiden uutisoinnin motiiveja ja eroja pohditaan niiden yhteiskunnallista taustaa vasten.
  • Monogioudi, Evanthia (Helsingin yliopisto, 2011)
    Protein modification via enzymatic cross-linking is an attractive way for altering food structure so as to create products with increased quality and nutritional value. These modifications are expected to affect not only the structure and physico-chemical properties of proteins but also their physiological characteristics, such as digestibility in the GI-tract and allergenicity. Protein cross-linking enzymes such as transglutaminases are currently commercially available, but also other types of cross-linking enzymes are being explored intensively. In this study, enzymatic cross-linking of β-casein, the most abundant bovine milk protein, was studied. Enzymatic cross-linking reactions were performed by fungal Trichoderma reesei tyrosinase (TrTyr) and the performance of the enzyme was compared to that of transglutaminase from Streptoverticillium mobaraense (Tgase). Enzymatic cross-linking reactions were followed by different analytical techniques, such as size exclusion chromatography -Ultra violet/Visible multi angle light scattering (SEC-UV/Vis-MALLS), phosphorus nuclear magnetic resonance spectroscopy (31P-NMR), atomic force (AFM) and matrix-assisted laser desorption/ionisation-time of flight mass spectrometry (MALDI-TOF MS). The research results showed that in both cases cross-linking of β-casein resulted in the formation of high molecular mass (MM ca. 1 350 kg mol-1), disk-shaped nanoparticles when the highest enzyme dosage and longest incubation times were used. According to SEC-UV/Vis-MALLS data, commercial β-casein was cross-linked almost completely when TrTyr and Tgase were used as cross-linking enzymes. In the case of TrTyr, high degree of cross-linking was confirmed by 31P-NMR where it was shown that 91 % of the tyrosine side-chains were involved in the cross-linking. The impact of enzymatic cross-linking of β-casein on in vitro digestibility by pepsin was followed by various analytical techniques. The research results demonstrated that enzymatically cross-linked β-casein was stable under the acidic conditions present in the stomach. Furthermore, it was found that cross-linked β-casein was more resistant to pepsin digestion when compared to that of non modified β-casein. The effects of enzymatic cross-linking of β-casein on allergenicity were also studied by different biochemical test methods. On the basis of the research results, enzymatic cross-linking decreased allergenicity of native β-casein by 14 % when cross-linked by TrTyr and by 6 % after treatment by Tgase. It can be concluded that in addition to the basic understanding of the reaction mechanism of TrTyr on protein matrix, the research results obtained in this study can have high impact on various applications like food, cosmetic, medical, textile and packing sectors.
  • Salminen, Heidi (Helsingin yliopisto, 2003)
  • Natunen, Jari (Helsingin yliopisto, 1999)
  • Oksanen, Esko (Helsingin yliopisto, 2009)
    Inorganic pyrophosphatases (PPases, EC hydrolyse pyrophosphate in a reaction that provides the thermodynamic 'push' for many reactions in the cell, including DNA and protein synthesis. Soluble PPases can be classified into two families that differ completely in both sequence and structure. While Family I PPases are found in all kingdoms, family II PPases occur only in certain prokaryotes. The enzyme from baker's yeast (Saccharomyces cerevisiae) is very well characterised both kinetically and structurally, but the exact mechanism has remained elusive. The enzyme uses divalent cations as cofactors; in vivo the metal is magnesium. Two metals are permanently bound to the enzyme, while two come with the substrate. The reaction cycle involves the activation of the nucleophilic oxygen and allows different pathways for product release. In this thesis I have solved the crystal structures of wild type yeast PPase and seven active site variants in the presence of the native cofactor magnesium. These structures explain the effects of the mutations and have allowed me to describe each intermediate along the catalytic pathway with a structure. Although establishing the ʻchoreographyʼ of the heavy atoms is an important step in understanding the mechanism, hydrogen atoms are crucial for the mechanism. The most unambiguous method to determine the positions of these hydrogen atoms is neutron crystallography. In order to determine the neutron structure of yeast PPase I perdeuterated the enzyme and grew large crystals of it. Since the crystals were not stable at ambient temperature, a cooling device was developed to allow neutron data collection. In order to investigate the structural changes during the reaction in real time by time-resolved crystallography a photolysable substrate precursor is needed. I synthesised a candidate molecule and characterised its photolysis kinetics, but unfortunately it is hydrolysed by both yeast and Thermotoga maritima PPases. The mechanism of Family II PPases is subtly different from Family I. The native metal cofactor is manganese instead of magnesium, but the metal activation is more complex because the metal ions that arrive with the substrate are magnesium different from those permanently bound to the enzyme. I determined the crystal structures of wild type Bacillus subtilis PPase with the inhibitor imidodiphosphate and an inactive H98Q variant with the substrate pyrophosphate. These structures revealed a new trimetal site that activates the nucleophile. I also determined that the metal ion sites were partially occupied by manganese and iron using anomalous X- ray scattering.
  • Lehtiö, Lari (Helsingin yliopisto, 2006)
    The first glycyl radical in an enzyme was described 20 years ago and since then the family of glycyl radical enzymes (GREs) has expanded to include enzymes catalysing five chemically distinct reactions. The type enzymes of the family, anaerobic ribonucleotide reductase (RNRIII) and pyruvate formate lyase (PFL) had been studied long before it was known that they are GREs. Spectroscopic measurements on the radical and an observation that exposure to oxygen irreversibly inactivates the enzymes by cleavage of the protein proved that the radical is located on a particular glycine residue, close to the C-terminus of the protein. Both anaerobic RNRIII and PFL, are important for many anaerobic and facultative anaerobic bacteria as RNRIII is responsible for the synthesis of DNA precursors and PFL catalyses a key metabolic reaction in glycolysis. The crystal structures of both were solved in 1999 and they revealed that, although the enzymes do not share significant sequence identity, they share a similar structure - the radical site and residues necessary for catalysis are buried inside a ten stranded $\ualpha $/$\ubeta $-barrel. GREs are synthesised in an inactive form and are post-translationally activated by an activating enzyme which uses S-adenosyl methionine and an iron-sulphur cluster to generate the radical. One of the goals of this thesis work was to crystallise the activating enzyme of PFL. This task is challenging as, like GREs, the activating component is inactivated by oxygen. The experiments were therefore carried out in an oxygen free atmosphere. This is the first report of a crystalline GRE activating enzyme. Recently several new GREs have been characterised, all sharing sequence similarity to PFL but not to RNRIII. Also, the genome sequencing projects have identified many PFL-like GREs of unknown function, usually annotated as PFLs. In the present thesis I describe the grouping of these PFL family enzymes based on the sequence similarity and analyse the conservation patterns when compared to the structure of E. coli PFL. Based on this information an activation route is proposed. I also report a crystal structure of one of the PFL-like enzymes with unknown function, PFL2 from Archaeoglobus fulgidus. As A. fulgidus is a hyperthermophilic organism, possible mechanisms stabilising the structure are discussed. The organisation of an active site of PFL2 suggests that the enzyme may be a dehydratase. Keywords: glycyl radical, enzyme, pyruvate formate lyase, x-ray crystallography, bioinformatics
  • Ekman, Aino (1935)
  • Jalava, Katri (2014)
    Vesijohtoverkoston häiriöt aiheuttavat usein vatsatautiepidemioita, joissa aiheuttajina on useita patogeenisiä organismeja. Tässä tutkimuksessa selvitettiin itäsuomalaisen kunnan laaja vesivälitteinen epidemia käyttäen monitieteistä lähestymistapaa hyödyntäen kehittyneitä epidemiologisia, tilastollisia ja spatiaalisia menetelmiä. Maanrakennustöistä johtunut putkirikko sattui vesijohtoverkostoon Vuorelassa, Siilinjärvellä 4. heinäkuuta, 2012. Kaksi viikkoa myöhemmin terveyskeskukseen alkoi tulla poikkeuksellisen paljon vatsa-suolisto-oireisia potilaita, joten välittömät kontrollitoimet aloitettiin. Määritetyllä epidemia-alueella asui 2931 asukasta, joista 473 (16 %) vastasi nettipohjaiseen kyselytutkimukseen. Potilas- ja vesinäytteet tutkittiin usean mikrobin varalta ja jatkotutkimuksina tehtiin molekyylibiologisia tyypityksiä ja mikrobien kokonaislajimääritys. Tutkimuksessa kehitettiin menetelmä, jonka avulla pystyimme laskemaan etäisyyden putkirikkoon vesijohtoverkostoa pitkin. Kyselytutkimuksessa saatuja vastauksia ja etäisyyttä putkirikosta käytettiin useissa univariaatti- ja monimuuttujamalleissa selittäjinä. Lisäksi käytimme analysointiin spatiaalista logistista regressiomenetelmää. Pääasialliset oireet olivat vatsakipu, pahoinvointi ja ripuli. Taudinkuva oli lievä, oireiden kesto oli keskimäärin kolme päivää. Potilas- ja vesinäytteistä todettiin useita patogeenejä joiden tiedetään aiheuttavan lievää vatsatautia ja/tai kuvaavan ulostesaastutusta vedessä, muun muassa sapoviruksia, yksi Campylobacter jejuni, arkobakteereita ja erilaisia E. coleja (EHEC, EPEC, EAEC ja EHEC). Taudinkuvan perusteella tehtiin tapausmääritelmä, jota käytettiin vastemuuttujana tilastollisissa malleissa. 4 Käsittelemättömän vesijohtoveden juominen epidemia-alueella aiheutti kohonneen riskin sairastua, RR (riskisuhde, altistuneiden osuus sairastuneissa suhteessa altistuneiden osuuteen terveissä) oli 5.6 (95 %:n luottamusväli 1.9-16.4). Tämä riski kasvoi juodun veden määrän suhteessa eli todettiin ns. annosvasteisuus. Jokaiselle asukkaalle laskettiin etäisyys putkirikosta vesijohtoverkostoa pitkin käyttäen tässä tutkimuksessa kehitettyä menetelmää. Mitä lähempänä henkilö asui putkirikkopaikkaa, sitä suurempi riski hänellä oli sairastua. Nuoremmat henkilöt sairastuivat vanhempia herkemmin. Sekä log- että logistisessa monimuuttujamallissa tilastollisesti merkitseviksi selittäjiksi osoittautuivat ikä (käänteisesti), etäisyys putkirikosta (käänteisesti) ja vesijohtoveden juominen. Lisäksi ns. spatiaalinen tekijä (kuvaten tartunnan leviämistä henkilöstä toiseen, mittausvirhettä etäisyysmuuttujassa ja veden epälineaarista virtausta vesijohtoverkostossa) oli merkitsevä. Tässä tutkimuksessa käytetyt uudenlaiset menetelmät paransivat epidemian lähteen selvittämistä ja auttoivat määrittämään epidemian laajuuden ja sairastuneiden määrän. Näitä menetelmiä voidaan hyödyntää epidemiaselvityksissä jatkossa.
  • Fossi, Marja (Helsingin yliopisto, 2006)
    Brachyspira pilosicoli causes porcine intestinal spirochaetosis, which is manifested by a mild, persistent diarrhoea among weaned pigs at the age of 7-14 weeks. The growth of diseased pigs is retarded and their feed conversion is lowered, resulting in diminished production. These studies were designed to investigate the molecular epidemiology of B. pilosicoli in Finnish sow herds and to improve laboratory diagnostics for B. pilosicoli. Infectivity of the rare hippurate-negative biotype of B. pilosicoli was examined by an infection trial and eradication of B. pilosicoli from a sow herd was demonstrated. A high genetic diversity was observed among 131 B. pilosicoli strains obtained from 49 sow herds located in the two major pork production areas of Finland. A high discriminatory power of pulsed-field gel electrophoresis (PFGE) was established with either SmaI or MluI used as a restriction enzyme. Common genotypes between the herds were rare, and no clustering of the genotypes according to the two geographical areas was observed. A single genotype could persist in a herd for several years; however, genetic recombination among B. pilosicoli strains might occurr. The epidemic nature of B. pilosicoli infection in Finnish pig farms was shown, and the role of migrating vectors or fomites for horizontal transmission was assessed as minor. The high discriminatory power of PFGE was further exploited to investigate hippurate-negative phenotypes of B. pilosicoli. No relationship between hippurate-negativity and genotypes of B. pilosicoli was detected. This finding was substantiated by comparative analyses of 16S rDNA nucleotide sequences of hippurate-negative and -positive isolates; different nucleotide positions of the strains were not predictive of the hippurate hydrolysis reaction. B. pilosicoli isolates from the same herd could possess an identical genome despite having a different capacity for hydrolysing hippurate. The congruent phylogeny of hippurate-negative and -positive B. pilosicoli was further ascertained by an ultrastructural study; the two biotypes shared all of the features unique to the species B. pilosicoli. In conclusion, the expression of hippurate hydrolysis can vary within a single B. pilosicoli clone, and thus, the hippurate test can not be used alone for differentiation of porcine B. pilosicoli. An occasional hippurate-negativity can disturb the phenotype-based differential diagnostics of B. pilosicoli. A B. pilosicoli-specific D-ribose test was therefore established to strengthen the diagnostics protocol. Sixty unrelated B. pilosicoli strains and 35 strains of other porcine Brachyspira species were studied for D-ribose utilization by an indirect method based on recording the pH reduction of a broth culture in the presence of D-ribose. All B. pilosicoli strains, regardless of the hippurate reaction, could utilise D-ribose, whereas the strains of the other Brachyspira species were D-ribose-negative. These results enabled the construction of an amended classification scheme for phenotypic differentiation of porcine B. pilosicoli. Experimental pigs were inoculated either with a hippurate-negative B. pilosicoli strain or with a B. pilosicoli type strain. Somewhat unexpectedly, the pigs in both trial groups remained healthy. Only the hippurate-negative B. pilosicoli strain could be reisolated from two of eight infected pigs. An explanation for the silent infection or lack of infection may lie in the challenge procedure, strain attenuation, environmental conditions, absence of concomitant enteropathogens or the feeding regimen. The pathogenicity of hippurate-negative B. pilosicoli should be further studied in modified conditions for trial pigs. Eradication of a chronic B. pilosicoli infection without total depopulation was attempted in a 60-sow farrowing herd. The principles for eradication of B. hyodysenteriae, the cause of swine dysentery, were applied. Special attention was paid to sanitary measures, relocation of animals according to age groups to nearby shelters, husbandry principles and adequate medication. The eradication was successful; the diarrhoea of the young growers disappeared, and B. pilosicoli was not detected in any sample during the 4.5-year follow-up.