Väitöskirjat

Recent Submissions

  • Hoilijoki, Sanni (Helsingin yliopisto, 2017)
    This thesis investigates interactions between solar wind and the magnetosphere of the Earth using two global magnetospheric simulation models, GUMICS-4 and Vlasiator, which are both developed in Finland. The main topic of the thesis is magnetic reconnection at the dayside magnetopause, its drivers and global effects. Magnetosheath mirror mode waves and their evolution, identification and impacts on the local reconnection rates at the magnetopause are also discussed. This thesis consists of four peer-reviewed papers and an introductory part. GUMICS-4 is a magnetohydrodynamic model solving plasma as a single magnetized fluid. Vlasiator is the world s first global magnetospheric hybrid-Vlasov simulation model, which solves the motion of ions by describing them as velocity distribution functions, whereas electrons are described as a charge neutralizing fluid. Vlasiator is able to solve ion scale physics in a global scale simulation. However, it is computationally heavy and the global simulations are currently describing Earth s magnetosphere only in two spatial dimensions, whereas the velocity space is three dimensional. This thesis shows that magnetic reconnection at the dayside magnetopause is controlled by several factors. The impact of dipole tilt angle and sunward component of the interplanetary magnetic field on magnetopause reconnection is investigated with a set of GUMICS-4 simulations. Using Vlasiator simulations, this thesis shows that local reconnection rate is highly variable even during steady solar wind and correlates well with an analytical model for 2D asymmetric reconnection. It is also shown that the local reconnection rate is affected by local variations in the magnetosheath plasma. Fluctuations in the magnetosheath parameters near X-lines are partly generated by mirror mode waves that are observed to grow in the quasi-perpendicular magnetosheath. These results show that that the local reconnection rate at the X-lines is affected not only by the fluctuations in the inflow parameters but also by reconnection at nearby X-lines. Outflow from stronger X-lines pushes against the weaker ones and might ultimately suppress reconnection in the weaker X-lines. Magnetic islands, 2D representations of FTEs, form between X-lines in the Vlasiator simulations. FTEs propagate along the dayside magnetopause driving bow waves in the magnetosheath. The bow waves propagate upstream all the way to the bow shock causing bulges in the shock, from which solar wind particles can reflect back to the solar wind causing local foreshocks. The overall conclusion of this thesis is that the ion scale kinetic physics is important to accurately model the solar wind magnetosheath magnetopause interactions. Vlasiator results show a strong scale-coupling between ion and global scales: global scale phenomena have an impact on the local physics and the local phenomena may have unexpected impacts on the global dynamics of the magnetosphere. Neglecting the global scales in local ion scale simulations and vice versa may therefore lead to incomplete description of the solar wind magnetosphere interactions.
  • Päivärinta, Essi (Helsingin yliopisto, 2017)
    A diet rich in fruits and vegetables has been suggested to decrease the risk of colorectal cancer and the protective effects of these foods could probably be at least partly mediated by their polyphenolic compounds. The number of different polyphenols is huge and their effects on cells and tissues may differ. The promising results on chemopreventive effects of ellagitannin-rich pomegranate suggest that the other dietary sources of ellagitannins may also be effective in cancer prevention. The overall aim of the research reported in this thesis was to study the effects of cloudberry (Rubus chamaemorus), which is rich in ellagitannins, on all phases of intestinal tumour development. Specifically, the effects of cloudberry on the first two phases of carcinogenesis, initiation and promotion, were studied using the ApcMin mouse model. In addition, the effects of cloudberry extract on the indicators of the last phase of cancer development, progression and metastasis, and particularly cancer cell migration that is essential for this phase, were studied using scattering and wound healing assays in hepatocyte growth factor-induced HT29 and HCA7 human colon adenocarcinoma cell lines. A whole-cloudberry diet containing 10% (w/w) freeze-dried cloudberries significantly decreased the number and size of intestinal adenomas in ApcMin mice. In contrast, cloudberry seeds, cloudberry pulp, or pure ellagic acid, when incorporated into the diets in concentrations that corresponded to the whole-cloudberry diet, had no apparent effect. The effects of cloudberry on the development of adenomas were also compared with the effects of bilberry (Vaccinium myrtillus), which is rich in anthocyanins. Both berries decreased the number of adenomas, but their effects of adenoma size were different: thus, the adenoma size was decreased by cloudberry and increased by bilberry in comparison to the control diet. The opposite effects of the berries on tumour growth were associated with the changes in the gut microbiota, intestinal immunity, and the expression of energy metabolism-related genes. The activation of Met, which is also known as hepatocyte growth factor receptor induces cell migration and is considered to play an important role in tumour metastasis. Cloudberry extract inhibited cell migration by inhibiting the activation of Met in hepatocyte growth factor-induced human HT29 and HCA7 colon adenocarcinoma cells, and thus Met signalling and consequent activation of the phosphatidylinositol 3-kinase/AKT pathway. The activation of Met signalling in the tumours of cloudberry-fed ApcMin mice was also inhibited. The results of the research presented in this thesis suggest that consumption of cloudberry or cloudberry preparations may reduce the risk of colon cancer, slow down the growth of colon adenomas, and have therapeutic value in reducing cancer progression and metastasis. Long-term studies in human subjects are needed to confirm these results.
  • Rissanen, Antti-Pekka (Helsingin yliopisto, 2017)
    Oxygen Delivery and Utilization during Acute Dynamic Exercise: Effects of Polycystic Ovary Syndrome, Type 1 Diabetes, and Exercise Training Cardiovascular risk is increased in polycystic ovary syndrome (PCOS) and type 1 diabetes (T1D). Peak pulmonary O2 uptake (V̇O2peak) is a strong and independent predictor of cardiovascular risk. This thesis aimed at studying O2 delivery and utilization (i.e., integrated components of V̇O2 response to exercise) during acute dynamic exercise in healthy individuals and individuals with PCOS or T1D. The adaptations induced by long-term exercise training were also examined in individuals with and without T1D. Data on 22 healthy adult men (Study I), 15 adult overweight or obese women with and 15 without PCOS (Study II), seven adult men with and 10 without T1D (Study III), and eight adult men with and eight without T1D (Study IV) were analyzed. The groups were matched for age, anthropometry, and leisure-time physical activity (II, III) or baseline V̇O2peak (IV). PCOS women and men with T1D had no clinically overt cardiovascular disease. The subjects performed maximal incremental treadmill (I) or cycling (II-IV) exercise tests, and in Study IV the subjects did so both before and after a 1-year individualized exercise training intervention. Alveolar gas exchange (I-IV), arterial O2 saturation (I-IV), heart rate (I-IV), cardiac pump function (II, III), and active leg muscle deoxygenation (I, III, IV) and blood flow (III) (near-infrared spectroscopy [NIRS]), were monitored during the exercise tests. In Study IV, peak O2 pulse was calculated to reflect cardiac pump function. Blood volume (III), hemoglobin concentration (I-IV), and glycosylated hemoglobin A1c (III, IV) were determined. Reduced V̇O2peak, reduced peak systemic O2 extraction, and a pronounced cardiac response to increasing V̇O2 but otherwise intact systemic O2 delivery were observed in overweight and obese PCOS women. Reduced peak cardiac pump function, being associated with reduced blood volume, and independently deteriorated peak active leg muscle blood flow led to reduced V̇O2peak and were suggested to be associated with glycosylated hemoglobin A1c in men with T1D. The 1-year training intervention improved V̇O2peak and peak O2 pulse similarly in men with and without T1D but did not affect NIRS-derived local active muscle O2 extraction or glycosylated hemoglobin A1c in men with T1D. The associations between training dose and responses were consistent in healthy men but not in men with T1D. This thesis provides novel information on PCOS- and T1D-related early signs of subclinical cardiovascular dysfunction and leads future multi-disciplinary research to identify more detailed mechanisms behind and the clinical significance of the findings.
  • Oiva, Jani (Helsingin yliopisto, 2017)
    Acute pancreatitis (AP) is common disease with a wide range of clinical manifestations. In most cases it is a self-limiting local inflammation. However, about 20-30% of the patients develop a more severe form of the disease (moderately severe or severe AP), which is complicated by systemic inflammation, organ dysfunction (OD) and possibly pancreatic necrosis. To prevent mortality, it would be crucial to identify at admission the patients at risk to develop a more severe form of AP, and to provide them with maximal supportive care. The present studies were designed to delineate the blood leucocyte signaling profiles in patients with AP and OD, and to investigate whether circulating trypsinogen-3 is associated with AP. The study consisted of four parts, in all of which the patients were admitted to hospital because of AP, and treated in the Intensive Care Unit for AP complicated by OD and immunosuppression. Studies I-III consisted of a cohort of 13 patients (with additional three patients in study II) and study IV of 82 patients. Phosphorylation of nuclear factor-κB (NFκB), mitogen-activated protein kinases (MAPK) p38 and extracellular signal-regulated kinases 1/2 (ERK1/2), and signal transducers and activators of transcription (STATs) 1,3,5,6 were studied from appropriately stimulated and non-stimulated blood samples using phospho-specific whole blood flow cytometry. In addition, transmigration of monocytes and polymorphonuclear leucocytes (PMNLs) were investigated using cells of an endothelial cell line. Trypsinogen-3 was measured with a new specific sandwich-type immunoassay to investigate it s clinical utility as a diagnostic and predictive tool in AP. We found that in AP patients monocytes have impaired NFκB and STAT1 activation, which may increase susceptibility to secondary infections. p38 activation is normal and STAT3 activation is depressed, which may contribute to the maintenance of systemic inflammation. ERK1/2 activation is impaired which may depress monocytes transmigration and may increase the risk for infection. The lymphocytes showed impaired NFκB activation, which may increase the risk for secondary infection. p38 activation was enhanced, which may sustain inflammation. Constitutive STAT3 activation may favour Th17 lineage of CD4+ lymphocyte differentiation. STAT1 activation is impaired and STAT6 activation enhanced, which denotes a shift from Th1 towards Th2 differentiation. The PMNLs showed depressed NFκB activation, normal p38 activation and decreased ERK1/2 activation. STAT3 was constitutively activated in five patients. Transmigration of the PMNLs was increased, which may sustain end organ dysfunction. Trypsinogen-3 distinguished AP patients from controls with high accuracy. However, it did not predict the severity of AP. In conclusion, these studies show that AP patients with OD and immunosuppression have multiple aberrations in blood leucocyte signalling pathways. These results may offer a potential predictive marker for the development of OD or secondary infections. Trypsinogen-3 can detect patients with AP but does not predict the severity of the disease.
  • Lumme, Sonja (Helsingin yliopisto, 2017)
    In most countries, the health care system aims to achieve equity as one of its primary goals. However, evident and persistent inequities in health care exist despite the improvement in the overall level of morbidity, health care performance and health care technology. This thesis develops statistical methods to evaluate socioeconomic equity in health care using register data. Moreover, this thesis provides information on socioeconomic equity in health care in Finland between 1992 and 2010 from several viewpoints. This thesis utilises two outcomes the use of coronary revascularisations and mortality amenable to health care interventions as empirical examples of the use of individual-level register data. Coronary revascularisation is a common invasive procedure and provides a good indication of health care system performance. Amenable mortality refers to causes of death that should be avoided in the presence of timely and effective health care interventions. It serves as an indirect measure of performance and the quality of health care. Data on revascularisations were obtained from the Care Register for Health Care and data on amenable deaths from the National Causes of Death statistics. These datasets were individually linked to population registers maintained by Statistics Finland to obtain sociodemographic data. This thesis develops a method to compare regional differences in socioeconomic equity in health care. The method takes dependence of observations within regions into account and its advantage is in overcoming the problems associated with random error in small regions. Additionally, it takes into account the effect of variation in the population size by age and socioeconomic position in regions in addition to different needs for health care. The existing methods measuring absolute differences do not provide solutions for evaluating absolute inequity in health care while taking the need for care into account. This thesis proposes a non-numerical approach to evaluating absolute horizontal socioeconomic equity in health care. Moreover, this study presents methods to assess uncertainty in the inequity indices when using register data. Evaluation of the uncertainty of the equity measures ensures that comparisons at different levels (between hospitals, areas, countries, in time) are meaningful. Finally, this thesis introduces an improved approach to studying socioeconomic equity in the effectiveness of health care. The approach uses amenable mortality as an indicator of health care performance and allows for an analysis of time trends in equity. Causes of deaths are assigned to categories according to the time and site of the interventions, which allows the indicative estimation of the effect of different sectors of health care systems on inequity. This study detected marked and persistent relative horizontal inequity in the use of revascularisations favouring the better-off in the period 1995 2010 in Finland. Contrary to earlier research, this study found no decrease in relative inequity. The results suggest that absolute horizontal inequity decreased although this cannot be quantified numerically. However, differences in inequity between regions were minor in 2001 2003, especially among men. The results of this study indicate that socioeconomic inequities in relative terms in deaths amenable to health care were marked and increased between 1992 and 2008 in Finland. Inequity was greater in deaths amenable to specialised health care, but the influence of primary health care on widening inequities was more substantial. In absolute terms, major socioeconomic inequity in amenable mortality remained. These results suggest that socioeconomic disparities in either access to or quality of health care in Finland did not diminish. The results of this thesis should prompt a serious consideration of actions to improve equity in health care in Finland.
  • Kallio, Lauri (Helsingin yliopisto, 2017)
    The study discusses the philosophy of Finnish philosopher J.V. Snellman (1806-81). The focus is on Snellman's so-called philosophy of personality, which he presented in his work "Essay on the speculative Development of the Idea of Personality" (Tübingen, 1841). Besides this work he addressed his philosophy of personality in his other works and in his public lectures. In his philosophy of personality Snellman develops the concept of personality within the framework of G.W.F. Hegel's (1770-1831) philosophy. The concept of personality serves as a basis for Hegel's philosophy of right, and it plays an important role also in other parts of Hegel's system. However, he never provided a comprehensive definition of this concept. The essence of personality was debated among Hegelians after Hegel's death in 1831. In the course of the debate the Hegelian school split into two groups. At the time of publication of "The Idea of Personality" there was a serious rift between the Right- and the Left-Hegelians. The study analyzes Snellman's philosophy of personality in respect of Hegel's philosophy and in respect of the views of other Hegelians mainly D.F. Strauss (1808-74), L. Feuerbach (1804-72) and C.F. Göschel (1781-1861). I also attend to some contemporaries outside the Hegelian School like F.W.J. Schelling (1775-1854) and I.H. Fichte (1796-1879). The study is divided into six sections (A F). The first comprises an introduction and an outline of the structure of the study. The second section (B) discusses the historical context of Snellman's philosophy. The first subsection focuses on the Central European debate on Hegel's legacy. The second subsection deals with Snellman's life and his work on philosophy. The systematic part of the study comprises three sections (C E), which consider the dialectic of Snellman's work of 1841. This dialectic follows the outline of Hegel's philosophy of subjective spirit and culminates in the definition of personality. Snellman, however, exceeds the realm of the philosophy of subjective spirit, as he discusses e.g. the philosophy of religion. He also comments on the debate among Hegelians. According to Snellman, neither Right- nor Left-Hegelians are true to Hegel's philosophy. In effect, his own standpoint in the debate, as I will argue, comes close to that of the Left-Hegelians. The study concludes with a summary (F).
  • Laine, Tiina (Helsingin yliopisto, 2017)
    The demand for mechanized tree planting is expected to increase in the future. This dissertation assessed mechanized tree planting in Finland and suggests ways to improve its current productivity. The work on which this thesis is based was described in five peer-reviewed articles (I V) addressing four specific research questions (SQs) that focus on productivity and cost-competitiveness, automation, capacity utilization, and the quality of planting work. While productivity of mechanized planting is higher than manual methods, it is not yet cost-competitive. However, increasing efficiency by skilled operators and worksite selection make it possible for mechanized planting costs to remain lower than those of excavator spot mounding followed by manual planting. Increasing productivity and reducing operating costs are possible with an effective automatic seedling feeding system, although the Risutec APC is not yet sufficiently developed to reach that goal. Planting machine capacity is underutilized and could be utilized more effective to enhance productivity and cost-efficiency. Technical availability of planting machines in Finland is good, and the quality of mechanized planting work is high. Optimization and integration of the entire mechanized planting chain from the nursery to outplanting is important to minimize total cost. In summary, for mechanized planting to be effective the following criteria must be satisfied: machine reliability; highly-skilled machine operator; suitable worksite; seedling quality, availability, and supply to worksite. In the future, it is important to continue developing new and existing machines to enhance productivity, e.g., by continuously working planting machines.
  • Waltari, Harri (Helsingin yliopisto, 2017)
    The experiments at the Large Hadron Collider (LHC) have confirmed that the Standard Model (SM) is a good description of particle physics at the electroweak scale. The Standard Model is still incomplete, since it does not explain e.g. neutrino masses, dark matter, dark energy or gravity. Supersymmetry is a well motivated way to extend the Standard Model. The minimal supersymmetric Standard Model (MSSM) has become somewhat fine-tuned after the first run of the LHC and therefore the detailed study of nonminimal supersymmetric models is highly motivated. We studied phenomenological implications of some nonminimal supersymmetric models especially in the light of the recent discovery of a Higgs boson. Our studies focused on supersymmetry without R-parity and left-right symmetric supersymmetric models. In the MSSM a 125 GeV Higgs requires rather heavy superpartners. In nonminimal models the Higgs mass can be lifted by contributions from new particles at tree-level, loop-level or by mixing effects. We found that if we introduce spontaneous R-parity violation, the mixing between the SM-like Higgs and a right-handed sneutrino can increase the mass of the SM-like Higgs if the sneutrino-like state is lighter than 125 GeV. One does not need as heavy superpartners as in the MSSM and thus fine-tuning is not as severe. If the Higgs mass gets additional contributions, the squarks of the third generation can be more easily within the reach of the LHC. If R-parity is not imposed, the squarks can have new decay modes, which can have a large branching fraction. As an example we studied a model, where R-charges are identified with the lepton number and found that the discovery potential for the stop decaying to a bottom quark and a positron is well beyond 1 TeV squark masses. In left-right supersymmetry we studied the Higgs decay modes and the option of having a right-handed sneutrino as a dark matter candidate. We found that a loop-induced mixing of the bidoublets can either enhance or suppress the Higgs coupling to bottom quarks and thus change the signal strengths considerably. However, in the scan there was also a large number of points, where the couplings behaved close to those of the SM. The right-handed sneutrino is a part of a doublet in left-right symmetric models. We found that sneutrinos may annihilate via a D-term coupling to the Higgs and produce the observed relic density. If we assume the gauge coupling of the right-handed gauge interactions to be the same as for the left-handed ones, we were able to predict a range of masses for the sneutrino. We also showed that with 100 inverse femtobarns we could get a signal of superpartners from the sleptonic decays of the right-handed W-boson, if its mass is below 3 TeV.
  • Björklund, Heta (Helsingin yliopisto, 2017)
    This doctoral dissertation examines medicinal-magical amulets pertaining to the uterus and the protection of women and children, the accompanying tradition of magical texts, and the mythology and folktales of demons believed to kill children and parturient women. The amulets and the folktales of the demons they were believed to protect against are intertwined. The amulets cannot be studied merely as archaeological or art historical objects, but must be taken together with folktales and narrative charms. The amulets discussed in this dissertation are from Late Antiquity (250 750 CE) and the Middle Byzantine period (843 1204 CE), and they come from the areas of Syria, Palestine, Egypt, Greece, and Asia Minor. The stories of the demons these amulets protected against are even earlier; the first mentions date to the time of Sappho in Archaic Greece (6th 7th centuries BCE), and they still appear in manuscript copies as late as the 15th century CE. The amulets discussed in this dissertation represent only a fraction of the amulets from Antiquity to Byzantine times intended to aid in pregnancy and childbirth. They must be seen as part of a tradition of amulets and narrative charms (stories that themselves acted as magical protection) against disease-causing demons. In narrative charms, the demon (who is both disease-causing and the disease itself) is depicted as animal-like, non-human, and usually rising from the sea. She meets a divine figure (Artemis in the older versions of the story, King Solomon, Jesus, or Virgin Mary in the later ones), who interrogates and banishes her. In addition, I propose that seeing the amulets in the context of belief in the evil eye may help explain many of their features and accompanying stories. The evil eye was thought to cause all manners of maladies. Contextualized in terms of the Indo-European and Semitic wet-dry division of life, the evil eye steals the liquids of life: mother s milk, blood, and semen. By attacking the very essence of the household and its continued survival (i.e. reproduction), the evil eye was a significant element behind the amulets and narrative charms. Furthermore, the concept of the evil eye was an extremely important tool in conflict resolution in small, close-knit communities, as a specific conflict could be resolved by placing blame on an immaterial scapegoat while maintaining social cohesion by not identifying any single individual as guilty.
  • Könönen, Mari (Helsingin yliopisto, 2017)
    The peatlands in Southeast Asia have been impacted and turned to vast carbon dioxide sources (CO2) by land management often involving drainage and deforestation. The amount of released CO2 in decomposition is related to management intensity likely resulting from altered conditions for decomposition. However, the link between decomposition processes and land-use change are poorly understood. To provide insight to the effects of land-use change intensities to decomposition processes in Central Kalimantan, Indonesia, we examined physical (dry bulk density, total pore space, particle size) and chemical properties (pH, loss-on-ignition; total concentrations of N, P, K, C, Ca, Mg, Mn, Zn, Al, Fe, S, Si, DOC and DON; organic matter quality characterized by infrared spectroscopy and on compound level), which together were used to determine the decomposition stage and decomposability (i.e., substrate quality) of peat. The peat biological properties (microbial biomass and enzyme activity) were used to provide insight to the decomposition activity at various land-use types and as a response to known peat properties. The study sites were: near-pristine swamp (i) and drained (ii) forest, deforested and drained degraded (iii), agricultural (iv) and reforested (v) sites. At the most intensively altered deforested sites the peat was denser, finer and enriched with recalcitrant compounds. The highest enzyme activity and microbial biomass were in the surface peat of swamp forest, where the amount of labile carbohydrates was highest. The six years ago reforested site did not yet show signs of recovery in peat properties, which was likely due the limited litter production capacity of the young plantation and microbial activity limited by chemical weeding. The main conclusion is that the litter input, or rather the lack of it after land-use change, and intensive management practices forms the main factors affecting to decomposition processes and leading to poorer substrate quality and reduced biological activity.
  • Nurmi, Harri (Helsingin yliopisto, 2017)
    There are two vascular systems in the body, for blood and lymph, and both are indispensable for embryonic development. The closed circuit of blood vessels is responsible for oxygen and nutrient delivery to all compartments of the body and removal of CO2 and waste products from tissues. The open-ended lymphatic system works as a return route for fluid, immune cells and dietary lipids into the blood circulation. The heart is the central engine for blood flow whereas lymphatic flow is achieved by skeletal and smooth muscle contraction around the lymphatic vessels. Differences between the blood vascular and lymphatic systems are apparent, from the molecular to the functional level. However, the two types of vessels also share a number of signaling molecules and building blocks of vessels. The purpose of the studies presented in this thesis was to expand our knowledge about Vascular Endothelial Growth Factors (VEGFs) and their receptors in development and pathological conditions. In the first study, we found, surprisingly, that VEGFR-3, the receptor for the principal lymphatic vessel growth factor, VEGF-C, is crucial for the normal patterning of the developing blood vessels and that endothelial deletion of Vegfr3, but not VEGFR-3-blocking antibodies, leads to excessive blood vessel sprouting and branching. Furthermore, macrophages that express the VEGFR-3 and VEGFR- 2 ligand VEGF-C localized to the vessel branchpoints, and Vegfc heterozygous mice exhibited inefficient angiogenesis characterized by decreased vascular branching. Our second study focused on the pathological aspect of the atherosclerosis. By using the transgenic mouse that overexpress soluble VEGFR-3 (VEGF-C/D trap) we could link the impaired lymphatic vessels to lipoprotein metabolism, increased plasma cholesterol levels, and enhanced atherogenesis. In the third project we focused on the role of lymphangiogenic growth factors in the steady-state homeostasis of lymphatic vessels in adult mice. Our findings from this study indicated that the lymphangiogenic growth factors provide trophic and dynamic regulation of the intestinal lymphatic vasculature, which could be especially important in the dietary regulation of adiposity and cholesterol metabolism. Finally in the last study we discovered a new role of VEGF-C in the embryonic development. To our surprise, we found a striking VEGF-C dependent phenotype with defective fetal liver erythropoiesis that resulted severe anemia in the Vegfc deteled embryos. These studies have revealed a new viewpoint regarding the VEGF-C/VEGFR-3 pathway in embryonic and pathological conditions. With these results, our understanding of the VEGF family members has expanded beyond the blood and lymphatic vessel. Hopefully, this new knowledge will improve the possibilities to target the VEGF-C/VEGFR-3 pathway for the treatment of human diseases such as atherosclerosis, obesity, and vascular diseases.
  • Schroderus, Riikka (Helsingin yliopisto, 2017)
    The topics of this thesis in mathematics belong to the area of operator theory which, in general, studies linear transformations between complete normed vector spaces. Here, all operators considered are bounded and act on complex separable infinite-dimensional Hilbert space. A prototypical example of Hilbert spaces is formed by the square summable sequences of complex numbers. Other common Hilbert spaces consist of functions which are analytic on some open domain of the complex plane. The characteristic property of analytic functions is that they are locally given by a convergent power series and so the behaviour of such functions is rather rigid. Thesis consists of the introductory part and three research articles, the first and the third being co-authored with, respectively, E. A. Gallardo-Gutiérrez and H.-O. Tylli. Our focus in the first two articles is in the spectral properties of composition operators which are induced by linear fractional transformations (also known as Möbius maps). As the name suggests, a composition operator composes a function with a fixed mapping called the inducing map. In studying these operators we can take advantage of function theoretic tools, and it is not surprising that the properties of composition operator depend intricately on the inducing map. The spectrum of an operator acting on an infinite-dimensional space generalizes the concept of eigenvalues of a finite matrix. In general, determining the spectrum of a given operator is not an easy task. In the first article we compute the spectra of composition operators induced by certain linear fractional self-maps of the unit disc. Here the operators act on the whole range of weighted Dirichlet spaces which are Hilbert spaces of analytic functions on the unit disc. Earlier results in this context cover e.g. the classical Hardy space, the weighted Bergman spaces and the classical Dirichlet space. Our results complete the spectral picture of linear fractional composition operators on the weighted Dirichlet spaces. In particular, we found a way to compute the spectra of parabolic and invertible hyperbolic composition operators on the spaces that are contained in the classical Dirichlet space. The second article continues the study of the spectral properties of linear fractional composition operators in the corresponding setting on the upper half-plane. The analogous spaces of the half-plane differ significantly from their counterparts in the unit disc; for instance, not all linear fractional self-maps of the half-plane induce bounded composition operators. We were able to compute the spectra of all bounded linear fractional composition operators acting on the Hardy, and the weighted Bergman spaces of the upper half-plane. Moreover, we show that the essential spectra coincide with the spectra on all cases. One of the main tools is the Paley-Wiener theorem along with its generalizations which allow us to transfer the computations to certain Hilbert spaces defined on the positive real line. An operator is called universal if it has such a rich lattice of invariant subspaces that it models any given operator (up to a constant multiple) when restricted to some of its invariant subspaces. The definition of universal operators can be generalized to commuting n-tuples of operators. In the third article we consider general properties of universal operators on separable infinite-dimensional Hilbert spaces. The task of finding and analysing concrete universal operators have gained a lot of attention since they could help in answering the question whether every operator on a separable infinite-dimensional Hilbert space has a non-trivial invariant subspace. We study the properties of the whole class of universal operators and as one of our main results we prove that universal operators have a big essential spectrum containing the origin. In addition, we give new examples of universal operators and universal commuting pairs.
  • Kochetkova, Elena (Helsingin yliopisto, 2017)
    This study is devoted to technology transfer from the West (primarily from Finland) to the Soviet forestry industry during a period of rapid modernization under the rule of Nikita Khrushchev during the 1950s and 1960s. Under Khrushchev, the USSR sought to catch up and overtake America . However, in the post-war period the Soviet Union suffered from a dearth of technology and expertise, and technology transfer from more developed foreign industries became a crucial aspect of modernization. Despite geopolitical competition and a vast ideological divide, Khrushchev aimed to transfer updated Western technologies to the USSR in different forms and practices. The Soviet Union established scientific-technical connections with several countries. The main source of modern technologies and machinery needed for paper and pulp production in particular was neutral Finland, which could be considered as a window to Western technological achievements for the Soviet Union. Exemplifying unique relations of West and East in the Cold War, Finland sold many techniques and provided expertise within the framework of scientific-technical cooperation. This dissertation examines the role that technology transfer from the other side of the Iron Curtain played in Soviet modernization from 1955 to 1964. How did technical cooperation with a Western country develop in the context of the Cold War? How and in what forms did Soviet institutions and engineers transfer technologies? How did they deal with more advanced machinery and new expertise? How did they apply the new technologies and how did Soviet domestic research develop? Did these technologies help renew machinery, launch new production and enhance the development of the industry, as expected? If not, why? And, in general, did these foreign technologies lead to technological modernization? In answering these questions, the dissertation sometimes refers to previous periods in order to trace continuities and change. Examining a vast collection of archival and published sources and using methods of the history of technology, the dissertation is focused on the forestry industry, which was one of key fields for expected positive changes in Khrushchev`s modernization. Its technological improvement was necessary not only for the increase of pulp and paper production to meet expanding consumption demands; the forestry industry was also a supplier for a large number of other both civilian and military industries, the latter of which received particular importance during the Cold War. Several plants and factories annexed after the Second Would War (in particular from Finland and the Baltic states) provided for the production of new sorts of pulp needed for military use, and technological modernization of these factories as well as launching new production in other Soviet enterprises was seen as a crucial action for the development of many other industries. Cold War forestry technologies, thus, exemplified their capacity to be a site of exchange , enabling cooperation among different industries, engineers, scientists and institutions. The dissertation illustrates that technologies from Finland and from the West via Finland played a significant role in the Soviet economy while creating a need for continuing transfer. The Soviet leadership aimed to create its own innovations to launch domestic production of the newest technologies. While Soviet engineers succeeded in implementing some technologies, they failed to develop Soviet ones. The Soviet industry remained dependent on cooperation with countries with more advanced industry. The main reasons for this were shortages of raw materials. In addition, technical expertise in industrial enterprises contributed to this dependence. Additionally, within the USSR, there were barriers to technology transfer between institutions. Generally, the successful implementation of Western technologies was possible only when all the details, machinery and expertise, needed for the technology were transferred. At the same time, as a framework for cultural encounters, transfer entailed cultural impacts on Soviet engineers which helped them become more reflexive about work conditions and management practices at Soviet enterprises.
  • Tanskanen, Katri (Helsingin yliopisto, 2017)
    This dissertation studies the dramaturgy of ethics in contemporary Finnish drama. My understanding of ethics is based on Emmanuel Levinas’s philosophy and his considerations on the encounters between subject and other/Other. Theatre and literary researchers have been heavily influenced by Levinas’s thoughts and have considered what it means to encounter otherness in the context of art. This study participates in the debate and introduces a new viewpoint by concentrating on questions of dramaturgy and dramatic writing. It examines how genre, language, style, characters and other structural elements have the potential to create space for otherness by generating ambivalence, obstructing the habitual gaze and questioning hegemonic understandings. The Sublime was found to be a productive concept to analyse the aesthetics of otherness, because it is deeply concerned with questions about the way we perceive the world and its others or the way we understand and represent the relation between self and other/s. In this study, the sublime is understood in the broadest sense of the word, extending to cover also the grotesque, taboos and other ways to reach limits or break barriers. My three case studies are Laura Ruohonen’s Luolasto (Finnish National Theatre 2014), Leea and Klaus Klemola’s New Karleby (Tampere Theatre 2011) and Milja Sarkola’s Jotain toista. Henkilökohtaisen halun näyttämö (Q-theatre 2015). They all challenged dramatic conventions and created alternative dramaturgical strategies that are partly related to contemporary postdramatic theatre. Since dramaturgy is deeply related to ideologies, society, culture and politics, a study of the ethics of dramaturgy produced new knowledge about the politics of contemporary theatre and drama. Analyses influenced by Levinas tended to emphasize plurality and the presence of otherness, both in a subject and in society. Otherness in these works was related to nature and ecology, species and gender, but also to a subject’s own unconscious or repressed interiority. These dramas challenged their spectators by reflecting the gaze back to the audience, inviting them to reconsider their own thoughts, attitudes and beliefs, and their limited scope in front of infinity.
  • Ikävalko, Veli-Matti (Helsingin yliopisto, 2017)
    Out-of-school learning environments are a part of chemistry education and they follow the Finnish National Core Curriculum. Non-formal learning is also a current topic of research internationally. By using out-of-school learning environments such as the ChemistryLab Gadolin in teaching, it is possible to encourage adolescents towards learning about chemistry. These learning environments offer contents, activities and resources, which might not be available in schools. With the help of context-based and relevant contents in chemistry as well as with inquiry-based work instructions and methods it is possible to support meaningful chemical education. By developing teaching in cooperation with specialists in the industry, we are able to add relevance to chemistry education. The aim of design-based research was to develop a meaningful non-formal learning environment in chemistry that would support the execution of study visit. The research was divided into three parts: (1) problem analyses, (2) the design process and (3) the design product. There were four main research questions in this research: (i) What kinds of needs are there in chemistry education regarding context-based contents and relevance? (problem analyses), (ii) Which factors and actions support active study visit in non-formal learning environments in chemistry? (problem analyses), (iii) How to develop the non-formal learning environment in chemistry communally with specialists in the industry? (design process), and (iv) What kind of is a relevant non-formal learning environment in chemistry with its contents and methods for study visit? (design product). The design-based research consisted of two theoretical problem analyses, where one was connected to meaningful learning of chemistry and the other to learning environments in chemistry and study visits. In total there were four empirical problem analyses. These were carried out as case studies. The first one was about looking at the context-based worksheets (N=160) in upper secondary school chemistry books. The second problem analysis focused on chemistry teachers (N=13) and students (N=33) experiences in exploiting skills in chemistry in everyday life, as to say their experiences in relevance and contexts. In the third one, teachers (N=161) and students (N=300) aims for study visits in the ChemistryLab Gadolin were studied. In the fourth empirical problem analysis, chemistry teachers (N=87) activities before and after the study visit and and ways of assessment were researched. Data was collected with the help of interviews, survey forms and literary outputs. Research data was analyzed with deductive and inductive content analysis. Reliability of research was increased by data -, method -, theory - and researcher triangulation. The results of the problem analyses were taken into consideration in the layout of the aims of the design process. The aim of the design process was to develop the didactic viewpoint of a non-formal learning environment in chemistry that would support meaningful study visit. The design process included the following two parts: (i) the development of laboratory work sheets and (ii) the development of activities that support the study visit. The development of laboratory work sheets was carried out collaboratively in the ChemistryLab Gadolin with industry specialists (N=9) and with students studying to be chemistry teachers (N=10). There were characteristics connected to collaboration and novice operations in the collaborative design process concerning work instructions. During the development process, specialist and instructor s support was observed as important. A suitable instrument of evaluation for non-formal learning environments in chemistry was developed on the basis of teachers (N=161) and students (N=300) case study. A model, for developing activities that support study visit, was created from teachers (N=87) operational models during study visit. The research provided four kinds of research information: (i) information on relevant contents that support chemical education, hands-on laboratory working methods and learning environments, (ii) on the collaborative design process, (iii) on context-based learning and relevance, which can be promoted in cooperation with specialists in the industry, and (iv) on meaningful execution of non-formal study visits in chemistry and on the evaluation of the aims of a visit. According to the empirical problem analysis (the so called needs analysis) in this research, context-based and relevant contents in upper secondary school inquiry should be developed in a more versatile way. A third of laboratory work sheets in upper secondary level textbooks included relevant, context-based contents, where home economics was emphasized. Teachers and students were observed to emphasize topics in home economics on the individual level in a case study concerning everyday chemistry. According to research, chemistry teachers activities and methods concerning study visit are focused more on the time after the field trip. Before the visit, in the preparatory part, theory and working methods are revised, laboratory work sheets are given and rules and instructions concerning the visit are discussed together. In the part after the visit, more versatile methods, including revising, were used such as blog entries and exercises having to do with visual arts. Assessment was based on summative assessment, attitudes and skills. In a non-formal learning environment, formative evaluation that supports learning was used only a little. According to research, when planning a study visit in a non-formal learning environment it is important to take the following eight factors into consideration (the so called instrument of evaluation for a non-formal learning environment): (i) participation, (ii) relevance, (iii) material environment, (iv) using ICT, (v) inquiry, (vi) supporting teachers work, (vii) differentiation and (viii) clarity of instructions. In addition, it is important for a teacher to take into consideration the before and after activities with different methods and evaluation in a study visit. As design products, there were also nine new and relevant context-based laboratory work sheets, which especially supported Industry, technology and production category. Three work sheets were chosen to be developed further. The final products were observed to support the level of individual relevance as well as the societal and vocational levels. The relevance levels of the further developed work sheets were studied to the visiting groups of teachers (N=25) and students (N=88) in the ChemistryLab Gadolin. The results of the design-based research can be applied in developing meaningful context-based hands-on working in natural science education. Cooperation with the industry brings added value to increasing the relevance of teaching. Meaningful and outcome-based study visits to non-formal learning environments can be developed by exploiting research information. The non-formal learning environment evaluation instrument developed in this qualitative research can be applied when designing learning environments.