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  • Kittilä, Anniina (2015)
    Bedrock fracturing is considerably extensive and distinct in Finland, and the fractures that are open, conductive and interconnected usually control the groundwater flow paths in fractured bedrock. This highlights the importance of knowing the locations and hydraulic connections of water conducting fracture zones particularly in mining areas, because they can transport adverse substances outside the mining area. In this study, it is focused on examining possible hydraulic connections of bedrock groundwater by using the stable isotopes of oxygen (δ18O) and hydrogen (δ2H). The study was carried out in the Talvivaara mining area in Northeastern Finland alongside a project from the Geological Survey of Finland (GTK). After November 2012, when a leakage of acidic, metal-containing waste water occurred in the gypsum ponds, there was an urgent need to study the groundwater transport routes in the bedrock fractures. The aim was to find hydraulic connections between surface water and groundwater, and to study the flow of the groundwater in the fracture zones based on the different isotopic characteristics of waters from different sources and isotopic similarities. Most of the materials used in this study were obtained from the results of the project from the GTK. These materials included geophysical interpretations of the locations and water content of the main fracture zones and the results from the geochemical analyzes. Together with the interpretations of groundwater flow direction based on hydraulic heads these materials formed a frame for this study. The isotope composition of 39 water samples from bedrock wells, shallow wells and surface water was analyzed using cavity ring-down spectroscopy (CRDS) method. The surface waters were clearly distinguished based on their evident evaporation signal, but no significant such a signal was observed in the bedrock and shallow groundwaters. However, similarities between groundwater from different depths of same well were found, in addition to similarities between different wells along same fracture zones. Although the isotopes did not indicate surface water contamination, groundwater contamination with smaller amounts of water is possible, in which case the changes in isotope composition are not yet significant, while certain elements have elevated concentrations. A NE-SW oriented fracture zone passing in the center of the study area was concluded to have the most important role in collecting and transporting groundwater outside the mining area. More detailed interpretations would require regular sampling for a longer period of time to better distinguish naturally and artificially induced changes both in the isotopic but also geochemical compositions. Also the usage of packer tests possibly together with pumping tests would be useful in obtaining more comprehensive image of the groundwater flow in the fracture zones and their hydraulic connections.
  • Hakli, Raul (2010)
    This thesis studies the nature and logic of collective doxastic attitudes, or what is referred to in ordinary language as "group beliefs". Beliefs and other intentional attitudes are attributed to groups and collections of people, and such attributions are used to explain and predict the actions of groups. The thesis develops an understanding of group beliefs as voluntarily adopted views or acceptances rather than as ordinary beliefs. Such an understanding can provide new answers to questions concerning collective knowledge and justification of group beliefs, and it allows developing modal logics with collective doxastic and epistemic notions. The thesis consists of six articles. The first three articles are philosophical studies concerned with the nature of group beliefs. The last three articles are logical studies that aim at developing proof-theoretical calculi for reasoning about collective doxastic attitudes.
  • Harju, Elina (2013)
    Street children´s life situations have received a lot of attention both in the media and in research in the recent years. In the literature street children are often defined as being under the age of 18. In this thesis, the focus group is the street youth, meaning the adolescents and young adults who either live full-time in the streets or are otherwise strongly connected with the street life. The research interest was to study how poverty is present in the lives of the street youth, and how their experiences of poverty in the streets and their own agency change when they grow older. A further interest was to find out how street life enables transition into adult roles in the society. The theoretical background of the thesis consists of introducing the discussion of structure and agency in social sciences as a way to understand the social life, then introducing the relevant concepts of poverty and social exclusion. Poverty in this thesis is understood in its widest sense, as Amartya Sen has defined it: deprivations of basic capacities that a person has to live the kind of life he or she has a reason to value. Also, the contemporary research on street children is introduced, where the agency perspective has gained space. The thesis also takes a look at some situational factors of the case study country Zambia, which affect the lives of the country’s vulnerable children and youth. This thesis is an ethnographic research consisting of two field work periods in Zambia’s capital city Lusaka. These field work periods took place in July-August 2011 and 2012 in an organization working with street children and youth. The informants were a heterogeneous group of street youth, aged between 14 and 28 and connected to the street life from different positions. The data consists of field notes and 33 recorded interviews with the informants. The results show that most of the street youth expressed reluctance towards their current life in the streets with little prospects for change. Income-wise their poverty seemed to vary, but the money was spent to meet one’s instant needs. Poverty was further expressed in terms of experienced public disrespect and vulnerability to violence and abuse by other street youth as well as police authorities. It also meant remoteness and mistrust in one’s social relationships. Poverty in the streets caused dependency of substances leading to decreased ability to take care of oneself as well as violent behavior. Growing older in the streets seemed to bring increased feelings of wasted years and frustration in one’s life situation, which was in contrast to adult roles in the society. Prolonged street life brought a risk of adopting illegal means and violent and harmful conduct. However, this was not necessarily so, and some of the youth had taken distance to the street life abandoned many of their earlier street behaviors. As chances for employment were small, they were, however, still stuck in the streets to earn living.
  • Salmenniemi, Suvi (2007)
    This study analyzes civic activity, citizenship and their gendered manifestations in contemporary Russia. It is based on a case study conducted in the city of Tver , located in the vicinity of Moscow, during 2001-2005. The data consists of interviews with civic activists and municipal and regional authorities; observations of civic organizations; and a quantitative survey conducted among local civic groups. The theoretical and methodological framework of the study draws upon a micro perspective on organization, discourse analysis, gender and citizenship theories and Pierre Bourdieu s theory of fields and capital. This study develops theoretical understanding of the characteristics and logic of civic organization in Russia. It shows that social class centrally structures the field of civic activity. Organizations can be seen as a vehicle of the educated class to advocate their interests, help themselves and seek both social and individual-level change. The study also argues that civic organizations founded during the post-Soviet era are often an institutionalized form of informal social networks. Networks, which were a central element of everyday interaction in Soviet society, are a resource and often the only resource available that can be made use of in contemporary organizational activities. The study argues that gender operates as a key structuring principle in the Russian socio-political community. Civic activity is often discursively associated with femininity and institutional politics with masculinity. Women tend to participate more than men in civic organizations, while men dominate the formal political domain. The study shows that civic organizations are important loci of communality. This communality, however, differs from the communality envisioned in the communitarian and social capital debates in the West. It is selective communality , as it is restricted to the members of the organizations and does not create generalized reciprocity and trust. Civic organizations tend to build upon and reproduce the traditional Russian organizational form of circles , kruzhki. Along with the analysis of civic activities, the study also examines the redefinition of the role and functions of the state. The authorities interviewed in this study understand civic organizations as serving those goals and interests determined by the authorities, instead of viewing them as sites of citizens self-organization around interests and problems citizens themselves deem important, or as a counterforce to the state. By contrast, civic activists understand the core of organizational activity to be advocacy of their interests and rights, tackling social problems, the pursuit of wider social change and self-help. Co-operation between authorities and organizations tends to be personified and based upon unequal, hierarchical patron-client arrangements, which inhibits the development of democratic governance. The study will be published in Routledge Contemporary Russia and Eastern Europe Series later this year.
  • Nevalainen, Maarit (Unigrafia, 2014)
    The aim of this study was to investigate medical students and primary care physicians feelings of uncertainty, experiences of medical errors and ways of coping with them, and attitudes towards the career of a GP. In Study I the learning diaries (n=79) and writings on specific themes (n=94) of 22 students during their first clinical year were analysed by thematic content analysis. The topics uncertainty and medical errors were studied in more detail. Studies II and III are based on the responses of 5th-year students to a cross-sectional survey (Study II, n=307 and Study III, n=309, response rate 86%) during their main course in general practice. Study IV concerned younger (n=85) and experienced physicians (n=80) responses to an electronic survey related to uncertainty and experiences of medical errors (response rate 68%). Factors predisposing physicians to medical errors and means to avoid making them were assessed. In the second, third and fourth studies the responses were cross-tabulated. The variables are presented as means with standard deviations and percentages. Comparisons of categorial variables were carried out by using the X2 test or Fischer s exact test, comparisons of non-normally distributed continuous variables were made by using the Mann-Whitney U-test. (P values less than 0.05 were considered significant.) 95% CIs are presented for the most important results. Logistic regression analysis was used to explore which factors predicted good tolerance of uncertainty among GPs. A developmental path among the 3rd- to 4th-year medical students was discovered regarding their experiences of uncertainty and fears medical errors. All students wrote about several aspects of uncertainty. They also feared mistakes. However, they started gradually to be more confident in coping with responsibility. The 5th-year medical students were divided into two groups based on their tolerance of uncertainty and fear of medical errors. Those who tolerated uncertainty quite well or well (n=240, 78%) were older, more often males, and had been working for a longer time as locum doctors than those tolerating uncertainty poorly (n=67, 22%). In the latter group, 100% were afraid of medical errors, in the former group the figure was 86%. Those tolerating uncertainty poorly felt more often that a GP s work is too challenging and difficult and involves too much responsibility. About 3/4 of the fifth-year medical students considered the work of a GP positively versatile and challenging, but about 2/3 of them considered it to be too hasty and pressing. The females thought that a GP s work is too lonely. The males considered that a GP deals too much with non-medical problems and the work may be too routine and tedious. According to the majority of the students (82%) the most important aim of a GP s work is to identify serious diseases and refer such patients to specialized care. In the fourth study 6% of the younger and 1% of the experienced physicians tolerated uncertainty poorly. The younger physicians feared medical errors more (70% vs. 48%) and more often admitted having made an error (84% vs. 69%) compared to the experienced ones (48%). The experienced physicians apologized more willingly to their patients for an error. The younger physicians were more prone to use electronic databases and consult on site. Tolerance of uncertainty seems to develop gradually during the medical studies and this development also continues after graduation. Students are already aware of the possibility of a medical error. Almost all of them are afraid of them. Also half of the experienced physicians admitted to feeling some fear. The attitudes of fifth-year medical students reflect their experiences of general practice.
  • Kuusisto, Arniika (Waxmann, 2011)
    This study investigates how the religious community as a socialization context affects the development of young people's religious identity and values, using Finnish Seventh-day Adventism as a context for the case study. The research problem is investigated through the following questions: (1) What aspects support the intergenerational transmission of values and tradition in religious home education? (2) What is the role of social capital and the social networks of the religious community in the religious socialization process? (3) How does the religious composition of the peer group at school (e.g., a denominational school in comparison to a mainstream school) affect these young people s social relations and choices and their religious identity (as challenged versus as reinforced by values at school)? And (4) How do the young people studied negotiate their religious values and religious membership in the diverse social contexts of the society at large? The mixed method study includes both quantitative and qualitative data sets (3 surveys: n=106 young adults, n=100 teenagers, n=55 parents; 2 sets of interviews: n=10 young adults and n=10 teenagers; and fieldwork data from youth summer camps). The results indicate that, in religious home education, the relationship between parents and children, the parental example of a personally meaningful way of life, and encouraging critical thinking in order for young people to make personalized value choices were important factors in socialization. Overall, positive experiences of the religion and the religious community were crucial in providing direction for later choices of values and affiliations. Education that was experienced as either too severe or too permissive was not regarded as a positive influence for accepting similar values and lifestyle choices to those of the parents. Furthermore, the religious community had an important influence on these young people s religious socialization in terms of the commitment to denominational values and lifestyle and in providing them with religious identity and rooting them in the social network of the denomination. The network of the religious community generated important social resources, or social capital, for both the youth and their families, involving both tangible and intangible benefits, and bridging and bonding effects. However, the study also illustrates the sometimes difficult negotiations the youth face in navigating between differentiation and belonging when there is a tension between the values of a minority group and the larger society, and one wants to and does belong to both. It also demonstrates the variety within both the majority and the minority communities in society, as well as the many different ways one can find a personally meaningful way of being an Adventist. In the light of the previous literature about socialization-in-context in an increasingly pluralistic society, the findings were examined at four levels: individual, family, community and societal. These were seen as both a nested structure and as constructing a funnel in which each broader level directs the influences that reach the narrower ones. The societal setting directs the position and operation of religious communities, families and individuals, and the influences that reach the developing children and young people are in many ways directed by societal, communal and family characteristics. These levels are by nature constantly changing, as well as being constructed of different parts, like the pieces of a jigsaw puzzle, each of which alters in significance: for some negotiations on values and memberships the parental influence may be greater, whereas for others the peer group influences are. Although agency does remain somewhat connected to others, the growing youth are gradually able to take more responsibility for their own choices and their agency plays a crucial role in the process of choosing values and group memberships. Keywords: youth, community, Adventism, socialization, values, identity negotiations
  • Kosonen, Liisa (Helsingin yliopisto, 2008)
    This study was a longitudinal quantitative study of the acculturation, psychological well-being and sociocultural adaptation of Vietnamese arriving in Finland in 1979 to 1991 as children and adolescents. The first phase was carried out in 1992 on a random nation-wide sample of 97 Vietnamese comprehensive school students, matched with Finnish classmates and a follow-up of 59 of the original Vietnamese participants, now aged 20 – 31, took place in 2004. The aim of this study was to establish the causal effects of important predictors of acculturation outcomes, while duly acknowledging the impact of age and context on psychological well-being and sociocultural adaptation. Individual acculturation dimensions (language, values and identity) were found to be more significant for psychological well-being and sociocultural adaptation than ethnic, national, or bicultural profiles that were composites of the relevant languages, values and identities. Identity change occurred in the (ethnic) Vietnamese direction over time, while value change occurred in the (national) Finnish direction. Language proficiency in both Finnish and Vietnamese increased over time with favorable impacts on both psychological well-being and sociocultural adaptation. Initial psychological well-being predicted well-being (depression and self-esteem) as an adult, but sociocultural adaptation (school achievement) as a child or adolescent did not predict educational attainment as an adult. The greater Finnish proficiency as an adult, not having been depressed in childhood or adolescence, perceiving less discrimination as a child or adolescent, and identifying less as Finnish as an adult distinguished those with better psychological well-being (not depressed) in adulthood from those who were depressed. In predicting greater educational attainment in adulthood, perceiving less discrimination as a child or adolescent, on the one hand, and better Finnish language proficiency as an adult, more adherence to national (Finnish) independence values as an adult, but less of a Finnish identity as an adult, on the other hand, were the most important factors. The significance of perceived discrimination, especially in childhood and adolescence, for psychological well-being, as well as for long-term effects on both psychological well-being and sociocultural adaptation as an adult, shows the need for early psychological intervention and for policies focusing on improving inter-group relations. Key words: acculturation, psychological well-being, sociocultural adaptation, language, values, identity, Vietnamese, Finland, children, adolescents, young adults
  • Meinander, Kristoffer (Helsingin yliopisto, 2009)
    Thin film applications have become increasingly important in our search for multifunctional and economically viable technological solutions of the future. Thin film coatings can be used for a multitude of purposes, ranging from a basic enhancement of aesthetic attributes to the addition of a complex surface functionality. Anything from electronic or optical properties, to an increased catalytic or biological activity, can be added or enhanced by the deposition of a thin film, with a thickness of only a few atomic layers at the best, on an already existing surface. Thin films offer both a means of saving in materials and the possibility for improving properties without a critical enlargement of devices. Nanocluster deposition is a promising new method for the growth of structured thin films. Nanoclusters are small aggregates of atoms or molecules, ranging in sizes from only a few nanometers up to several hundreds of nanometers in diameter. Due to their large surface to volume ratio, and the confinement of atoms and electrons in all three dimensions, nanoclusters exhibit a wide variety of exotic properties that differ notably from those of both single atoms and bulk materials. Nanoclusters are a completely new type of building block for thin film deposition. As preformed entities, clusters provide a new means of tailoring the properties of thin films before their growth, simply by changing the size or composition of the clusters that are to be deposited. Contrary to contemporary methods of thin film growth, which mainly rely on the deposition of single atoms, cluster deposition also allows for a more precise assembly of thin films, as the configuration of single atoms with respect to each other is already predetermined in clusters. Nanocluster deposition offers a possibility for the coating of virtually any material with a nanostructured thin film, and therein the enhancement of already existing physical or chemical properties, or the addition of some exciting new feature. A clearer understanding of cluster-surface interactions, and the growth of thin films by cluster deposition, must, however, be achieved, if clusters are to be successfully used in thin film technologies. Using a combination of experimental techniques and molecular dynamics simulations, both the deposition of nanoclusters, and the growth and modification of cluster-assembled thin films, are studied in this thesis. Emphasis is laid on an understanding of the interaction between metal clusters and surfaces, and therein the behaviour of these clusters during deposition and thin film growth. The behaviour of single metal clusters, as they impact on clean metal surfaces, is analysed in detail, from which it is shown that there exists a cluster size and deposition energy dependent limit, below which epitaxial alignment occurs. If larger clusters are deposited at low energies, or cluster-surface interactions are weaker, non-epitaxial deposition will take place, resulting in the formation of nanocrystalline structures. The effect of cluster size and deposition energy on the morphology of cluster-assembled thin films is also determined, from which it is shown that nanocrystalline cluster-assembled films will be porous. Modification of these thin films, with the purpose of enhancing their mechanical properties and durability, without destroying their nanostructure, is presented. Irradiation with heavy ions is introduced as a feasible method for increasing the density, and therein the mechanical stability, of cluster-assembled thin films, without critically destroying their nanocrystalline properties. The results of this thesis demonstrate that nanocluster deposition is a suitable technique for the growth of nanostructured thin films. The interactions between nanoclusters and their supporting surfaces must, however, be carefully considered, if a controlled growth of cluster-assembled thin films, with precisely tailored properties, is to be achieved.
  • Soirinsuo, Juho (Helsingin yliopisto, 2012)
    This study investigates growth in the forest machine and timber haulage sectors in Finland. The purpose was to clarify the impact of growth on companies in financial terms and to compare growth strategies. The main questions this study tried to answer were whether it is profitable to grow in these sectors, and if yes, how. This study also studied growth in general in these sectors which have not been studied before. The companies were all located in Finland and their locations were quite scattered. The companies selected were large in turnover compared to the sector average and all had increased their turnover between 2001 and 2006. The study consisted of two phases, the first of which focused on company financials and the second on management. Financial statements from 2001 to 2006 from the companies were retrieved from the Patentti- ja rekisterihallitus (National Board of Patents and Registration of Finland). In the second phase of the study, more material from the companies selected was collected by entrepreneur-interviews. A total of 23 forest machine entrepreneurs and 23 timber haulage entrepreneurs agreed to be interviewed. Entrepreneurs were personally interviewed in autumn 2008. The growth strategies of these companies were then analysed and combined with the financial analysis of the first phase. The main findings of the study were that there is a strong growth trend going on among the large companies of both these sectors. Another new phenomenon is increasing outsourcing between companies in these sectors. In other words, large companies in these sectors increasingly use smaller ones as their subcontractors. The study also found that it is possible to grow in both these sectors. In the forest machine sector, a good financial situation seemed to emphasize profitable growth. In the timber haulage sector the entrepreneur s role seemed to influence growth. The study revealed special features in both sectors, which entrepreneurs should note. In the forest machine sector, subcontracting seemed to bring good financial results in growth. However, growth was found to be quite a poor answer when trying to grow out of low profitability. In the timber haulage sector, it was found that economies of scale are almost non-existent because of high and increasing variable costs. It was also found that a growth strategy which focuses on optimising the amount of work, employees and machinery, combined with diversification seemed to bring the best outcome in terms of profitability. As a conclusion, it can be stated that the business environment of these sectors is changing rapidly driven by the change in the global forest industry when demands changes in term of customer service and efficiency from the entrepreneurs. Growth, when executed noting special features of the sector and the company s own strengths, may be the answer for better profitability. One surprising finding, however, was that both of these sectors, and especially growth-oriented companies, suffer from a labour shortage. The surprising part is that it is not a new phenomenon in these sectors, but rather a continuing problem which has been revealed for years and which can limit growth. A labour shortage is difficult for the entrepreneurs to influence, but a rather a matter of policy-makers.
  • Kjellman, Jakob (Helsingin yliopisto, 2003)
  • Virkajärvi, Perttu (Helsingin yliopisto, 2004)
  • Kaivo-oja, Noora (Helsingin yliopisto, 2007)
    In the ovary, two new members of the large TGF-beta superfamily of growth factors were discovered in the 1990s. The oocyte was shown to express two closely related growth factors that were named growth differentiation factor 9 (GDF-9) and growth differentiation factor 9B (GDF-9B). Both of these proteins are required for normal ovarian follicle development although their individual significance varies between species. GDF-9 and GDF-9B mRNAs are expressed in the human oocytes from the primary follicle stage onwards. This thesis project was aimed to define the signalling mechanisms utilized by the oocyte secreted GDF-9. We used primary cultures of human granulosa luteal cells (hGL) as our cell model, and recombinant adenovirus-mediated gene transfer in manipulating the TGF-b family signalling cascade molecules in these cells. Overexpression of the constitutively active forms of the seven type I receptors, the activin receptor-like kinases 1-7 (ALK1-7), using recombinant adenoviruses caused a specific activation of either the Smad1 or Smad2 pathway proteins depending on the ALK used. Activation of both Smad1 and Smad2 proteins also stimulated the expression of dimeric inhibin B protein in hGL cells. Treatment with recombinant GDF-9 protein induced the specific activation of the Smad2 pathway and stimulated the expression of inhibin betaB subunit mRNA as well as inhibin B protein secretion in our cell model. Recombinant GDF-9 also activated the Smad3-responsive CAGA-luciferase reported construct, and the GDF-9 response in hGL cells was markedly potentiated upon the overexpression of Alk5 by adenoviral gene transduction. Alk5 overexpression also enhanced the GDF-9 induced inhibin B secretion by these cells. Similarly, in a mouse teratocarcinoma cell line P19, GDF-9 could activate the Smad2/3 pathway, and overexpression of ALK5 in COS7 cells rendered them responsive to GDF-9. Furthermore, transfection of rat granulosa cells with small interfering RNA for ALK5 or overexpression of the inhibitory Smad7 resulted in dose-dependent suppression of GDF-9 effects. In conclusion, this thesis shows that both Smad1 and Smad2 pathways are involved in controlling the regulation of inhibin B secretion. Therefore, in addition to endocrine control of inhibin production by the pituitary gonadotropins, also local paracrine factors within in the ovary, like the oocyte-derived growth factors, may contribute to controlling inhibin secretion. This thesis shows as well that like other TGF-beta family ligands, also GDF-9 signalling is mediated by the canonical type I and type II receptors with serine/threonine kinase activity, and the intracellular transcription factors, the Smads. Although GDF-9 binds to the BMP type II receptor, its downstream actions are specifically mediated by the type I receptor, ALK5, and the Smad2 and Smad3 proteins.
  • Alanko, Tuomo (Helsingin yliopisto, 2000)
  • Tolonen, Jukka (Helsingin yliopisto, 2007)
    The intervertebral disc is composed of concentrically arranged components: annulus fibrosus, the transition zone, and central nucleus pulposus. The major disc cell type differs in various parts of the intervertebral disc. In annulus fibrosus a spindle shaped fibroblast-like cell mainly dominates, whereas in central nucleus pulposus the more rounded chondrocyte-like disc cell is the major cell type. At birth the intervertebral disc is well vascularized, but during childhood and adolescence blood vessels become smaller and less numerous. The adult intervertebral disc is avascular and is nourished via the cartilage endplates. On the other hand, degenerated and prolapsed intervertebral discs are again vascularized, and show many changes compared to normal discs, including: nerve ingrowth, change in collagen turnover, and change in water content. Furthermore, the prolapsed intervertebral disc tissue has a tendency to decrease in size over time. Growth factors are polypeptides which regulate cell growth, extracellular matrix protease activity, and vascularization. Oncoproteins c-Fos and c-Jun heterodimerize, forming the AP-1 transcription factor which is expressed in activated cells. In this thesis the differences of growth factor expression in normal intervertebral disc, the degenerated intervertebral disc and herniated intervertebral disc were analyzed. Growth factors of particular interest were basic fibroblast growth factor (bFGF or FGF-2), platelet-derived growth factor (PDGF), vascular endothelial growth factor (VEGF), and transforming growth factor beta (TGFβ). Cell activation was visualized by the expression of the AP-1 transcription promoters c-Fos and c-Jun. The expression was shown with either mono- or polyclonal antibodies by indirect avidin-biotin-peroxidase immunohistochemical staining method. The normal control material was collected from a tissue bank of five organ donors. The degenerated disc material was from twelve patients operated on for painful degenerative disc disease, and herniated disc tissue material was obtained from 115 patients operated on for sciatica. Normal control discs showed only TGFβ immunopositivity. All other factors studied were immunonegative in the control material. Prolapsed disc material was immunopositive for all factors studied, and this positivity was located either in the disc cells or in blood vessels. Furthermore, neovascularization was noted. Disc cell immunoreaction was shown in chondrocyte-like disc cells or in fibroblast-like disc cells, the former being expressed especially in conglomerates (clusters of disc cells). TGFβ receptor induction was prominent in prolapsed intervertebral disc tissue. In degenerated disc material, the expression of growth factors was analyzed in greater detail in various parts of the disc: nucleus pulposus, anterior annulus fibrosus and posterior annulus fibrosus. PDGF did not show any immunoreactivity, whereas all other studied growth factors were localized either in chondrocyte-like disc cells, often forming clusters, in fibroblast-like disc cells, or in small capillaries. Many of the studied degenerated discs showed tears in the posterior region of annulus fibrosus, but expression of immunopositive growth factors was detected throughout the entire disc. Furthermore, there was a difference in immunopositive cell types for different growth factors. The main conclusion of the thesis, supported by all substudies, is the occurrence of growth factors in disc cells. They may be actively participating in a network regulating disc cell growth, proliferation, extracellular matrix turnover, and neovascularization. Chondrocyte-like disc cells, in particular, expressed growth factors and oncoproteins, highlighting the importance of this cell type in the basic pathophysiologic events involved in disc degeneration and disc rearrangement. The thesis proposes a hypothesis for cellular remodelling in intervertebral disc tissue. In summary, the model presents an activation pattern of different growth factors at different intervertebral disc stages, mechanisms leading to neovascularization of the intervertebral disc in pathological conditions, and alteration of disc cell shape, especially in annulus fibrosus. Chondrocyte-like disc cells become more numerous, and these cells are capable of forming clusters, which appear to be regionally active within the disc. The alteration of the phenotype of disc cells expressing growth factors from fibroblast-like disc cells to chondrocyte-like cells in annulus fibrosus, and the numerous expression of growth factor expressing disc cells in nucleus pulposus, may be a key element both during pathological degeneration of the intervertebral disc, and during the healing process after trauma.
  • Susiluoto, Sannamaija (The Finnish Societ of Forest Science, Finnish Forest Research Instititute, Faculty of Agriculture and Forestry of the University of Helsinki, School of Forest Sciences of the University of Eastern Finland, 2013)
    The aim of the thesis was to study the factors limiting tree growth at treeline in Värriö and to investigate how reindeer grazing affects the vegetation and carbon balance of the treeline environment. The factors limiting Tree growth in the treeline ecotone were studied based on two hypotheses, the sink limitation hypothesis and the resource limitation hypothesis. Resource limitation included both carbon and nitrogen limitation. Three different manipulation treatments; debudding, defoliation and fertilization; were performed on treeline trees in Värriö to test the hypotheses. According to the results tree growth in Värriö is clearly restricted by resources. The factors supporting the resource limitation hypothesis were increased growth due to fertilization and debudding treatments and decreased stem diameter growth due to the defoliation treatment. Also, sapflow was not down-regulated due to debudding treatment. There was some increase (p=0.054) due to fertilization treatment in carbon isotope ratio, which furthermore supports the resource limitation hypothesis. Grazing did have an effect on the amount of carbon bind to vegetation, as the biomass of lichens was decreased due to grazing by 85 %. There were also changes in species composition due to grazing. Net carbon exchange correlated with the dwarf shrub cover, but the dwarf shrub cover did not change due to grazing. Overall, grazing did not affect the carbon fluxes on the area. Overall, the results showed that the tree growth in the study site is restricted by resources. Grazing affects the species composition and vegetation carbon stocks, but not on productivity or soil carbon stocks. Both treeline rise and increase in the abundance of the trees in the treeline would affect significantly on the carbons stocks of these ecosystems. Since reindeers might affect the regeneration of treeline, future research on the interactions between grazing and treeline progression would be important.
  • Pihlaja, Tuomo (1999)
  • Heinonen, Kerttu (1938)
  • Posti, Lauri (1942)