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  • Venninen, Tuulikki (Helsingin yliopisto, 2007)
    I have more often thought over what I am thinking and also I have often told it to others - professional development and collegial feedback on kindergarten teams. The need for professional feedback surfaces year after year in enquiries made among staff members in the field of early childhood education. Because the pressure to be effective adds to the workload of the heads of kindergartens, there are few opportunities to give staff concrete feedback on a daily basis. Because peers are able to observe each other close at hand, their reciprocal feedback can compensate for that of the kindergarten head. In this study the practical training process of collegial feedback is studied and also the opportunities for feedback as a means of supporting professional development in the context of kindergarten. The development project involving the entire kindergarten community (N=21) was implemented in 2003-2004 through three developing cycles. The Johar´s Window , produced by Luft and Jung with the Model of Situational Leadership by Hersey and Blanchard, acted as a theoretical frame of reference. It has been used in this study both for its qualitative and its quantitative methods. The data were carried out through questions, interviews, diaries, written descriptions and monthly evaluations. The qualitative and quantitative methods were also used in analysing the data. The results showed that during the training process, the staff as a giver of feedback moved from the professional basic level to the professional maturity level. Their awareness of both their own and their peers´ know-how expanded from the initial state to the final state. It became evident that team size is the essential key element in the practise of giving feedback to team members. The team atmosphere and the commitment of the team members are in significant factors in the training of giving and receiving feedback. As a result of analyses, delivering feedback was grouped into three categories: developmental feedback, descriptive feedback and either supportive or destructive feedback. Receiving feedback was likewise groupped into three categories: aspiring to develop, unaccommodating and accepting. The ability to control feelings improved along with the skills of giving feedback; it was possible to analyse development through the professional development model represented in the theory of the study. The results showed that professional know-how of other kinds also developed during the process. Giving feedback among fellow workers enables team members to receive feedback everyday. Training to give feedback means examining a field of professional know-how and also formulating shared rules. The results of this study give support to previous studies that have emphasised practical training in natural circumstances. Keywords: feedback, professional development, learning at work
  • Tikkanen, Ulla (Helsingin yliopisto, 2016)
    The everyday life and bonds of the spousal care of the elderly There are almost 24 000 Finns over the age of 65 who have made an agreement with the welfare state to be compensated for taking care of their family member in need. This agreement – typically concerning spousal care taking place at the mutual home of the spouses – is part of the current “public care” of the elderly in which the Finnish welfare state partners up with families. The public sector, the private sector and the third sector are all looking for their role and modes of collaboration in the network of care. Services supporting the elderly living at home are developed at the same time as the possibilities for institutional care are diminishing. The theoretical approach of the study draws on “figurational sociology” by Norbert Elias. In this study it means studying the ways in which people, human bonds and material objects form a figuration of care in which each element is interdependent of other elements and the whole. The aim of the research is to analyse the interrelated bonds in a way that opens up both their process of formation, and the experience of individuals as a part of the whole figuration of care. The study examines how the everyday life of the care of the elderly is formed, how the nature and bonds of care transform over different phases of care, and how various attachments and disruptions organize the figuration of everyday life. The research materials consist of qualitative interviews, ethnographic observation and a self-filled diary of the caregivers’ week, including their reflections of different days, significant relationships in the network of care and their personal notes. In all, it includes 21 interviews with 11 persons taking care of their spouse (between the ages of 67 and 83 years old) and with three persons in need of care. The empirical data was produced between April 2013 and February 2014. The research results depict a thick description of the everyday life of the spousal care. In addition to verbal analysis of the significant bonds of care, four different phases of care are presented visually placing the spouse caring and the spouse been cared for in the same visual frame (in the home in which the care takes place). The visual presentation illuminates the processes, practices and organising factors of the everyday life of care over time and space. The state of the bondedness can be described as porous, straining, heavy and sticky, depending on the intensity of needs of the spouse been cared for. The most important element of the figuration of care is “the demanding body” referring to the transformation of the spouse been cared for, from an actor to a “needy” body constantly demanding something from the caregiver, material surroundings and devices that gradually take over the whole space and life. The most significant material ties are formed to the home in which the care takes place, the assisting devices and medications. The ways in which humans are intertwined with material devices are examined through the metaphors of stick, walker, wheelchair and bed. The most central human bonds in the figurations of care are the one between the spouses and the one between them and the professionals involved. These central bonds are the most consequential in the formation of the figuration of care. The care of the spouse is physically and emotionally sticky full-time nursing that sometimes feels like being a prisoner. However, the caregivers are different and their characteristics make an impact on the way in which the figuration of care evolves. Taking care for one’s spouse who is gradually getting frail, is depicted as a process of loss and letting go of the personally significant contents of life, including the spouse her- or himself. Elias discusses this as a broken valency, one that tears apart a part of oneself. Discretion, empathy and respect toward the elderly by their family members, the public officials and the nursing staff would ease the caregivers’ burden. The study speaks for the benefits of the dynamic and holistic perspective of Elias’s figurational sociology in studying care. It enables to understand human interdependencies and needs as a part of a larger figuration of bonds, both human and material. By adding the material aspect in studying the human figuration of care, the study builds a fuller picture of the everyday realities of elderly care than work merely focusing on people. Keywords: aging, elderly care, family care, figurational sociology, human bonds, interdependency, material sociology, visualisation and welfare services
  • Mansikka, Jan-Erik (Helsingin yliopisto, 2007)
    TRANSFORMATIONS OF NATURE Science, Knowledge and Freedom in the Early Thinking of Rudolf Steiner. Perspectives on Waldorf Education in the light of the History of Ideas Waldorf Education is based on the worldview that Rudolf Steiner (1861-1925) developed to a wide-ranging anthroposophical movement in the first decades of the 20th century. This thesis takes as its departure the early thinking of Rudolf Steiner that precedes anthroposophy, and its main purpose is to uncover the tradition of ideas represented in Steiner´s early life and which, in different ways, have emerged in the practice of Waldorf Education. Through systematic analysis I attempt to bring to light different aspects of Steiner’s early thinking: his concept of science, his epistemological startingpoints and his philosophy of freedom. By departing from J. W. Goethe’s qualitative concept of science, Steiner strove in his early works to formulate a monistic worldview which appears to be closely related to the Romantic Movement and its philosophy of nature. Characteristic traits of his thinking are, on the one hand, a critique of a one-sided enlightenment and, on the other hand, an aspiration to see the world as a living organic unity. Human beings can, by developing our intuitive faculties, get a deeper understanding of the indissoluble relationship between man and nature. Against this background Steiner´s early thinking can be read as a special kind of romantic development narrative. Steiner’s early thinking also opens the way for romantic perspectives on Waldorf Education. It appears that many central aims and conceptions in Waldorf Education can be illuminated by the epistemological perspective upon which Steiner elaborated early in his life. An organic curriculum, phenomenological didactics and high ideal of freedom can be considered seen as educational applications of conceptions that played an important role in Goethe and his age. Thus, Waldorf Education provides in our contemporary society an exceptional set of educational values: a holistic education with romantic undertones.
  • Kaila, Risto (Helsingin yliopisto, 2001)
  • Bramante, Simona (Helsingin yliopisto, 2015)
    Despite the numerous advances in cancer therapy over the past 50 years, cancer still remains the major cause of mortality worldwide, and thus new and more efficient treatments are needed. Oncolytic viruses have shown promising results in preclinical and clinical studies for the treatment of solid tumors, but their efficacy often remains low. A multitude of viral strains, such as adenovirus, have been engineered to become tumor-selective and to stimulate the immune system against the tumors. One example of oncolytic virus is Ad5/3-D24-GMCSF, a tumor-selective 5/3 chimeric oncolytic adenovirus armed with the immunostimulatory granulocyte-macrophage colony-stimulating factor (GM-CSF). In this thesis, we studied the utility of Ad5/3-D24-GMCSF in the treatment of sarcoma, melanoma and breast cancer. The virus showed strong oncolytic potential in vitro and antitumor efficacy in immunodeficient animal models. Furthermore, replication-linked GM-CSF production stimulated the differentiation of human monocytes into macrophages, important for induction of antitumor immune responses. In immunocompetent Syrian hamsters with soft-tissue sarcoma (STS) tumors, Ad5/3-D24-GMCSF reached non-injected tumors through vascular circulation, suggesting its utility for the treatment of metastatic disease. We showed that combining Ad5/3-D24-GMCSF with chemotherapeutics that possess immunogenic properties (doxorubicin and ifosfamide) and that selectively reduce circulating regulatory T-cells (cyclophosphamide), enhanced adenoviral replication and induced immunogenic cell death, setting the stage for clinical testing of combination regimens. Finally we reported safety and possible signs of efficacy in 40 patients with advanced sarcoma, melanoma and breast cancer, who were treated in the context of an Advanced Therapy Access Program (ATAP). Treatments were overall well-tolerated, and objective signs of treatment benefits were also observed. Therefore, our results confirm previous good data regarding Ad5/3-D24-GMCSF as a promising agent for treatment of cancer. Furthermore, our data may prove useful for clinical development of oncolytic adenoviruses combined with low-dose chemotherapy for the treatment of advanced sarcoma, melanoma and breast cancer, and may help to design optimal clinical trials.
  • Bauerschmitz, Gerd Johannes (Helsingin yliopisto, 2007)
    Gene therapy is a promising novel approach for treating cancers resistant to or escaping currently available modalities. Treatment approaches are based on taking advantage of molecular differences between normal and tumor cells. Various strategies are currently in clinical development with adenoviruses as the most popular vehicle. Recent developments include improving targeting strategies for gene delivery to tumor cells with tumor specific promoters or infectivity enhancement. A rapidly developing field is as well replication competent agents, which allow improved tumor penetration and local amplification of the anti-tumor effect. Adenoviral cancer gene therapy approaches lack cross-resistance with other treatment options and therefore synergistic effects are possible. This study focused on development of adenoviral vectors suitable for treatment of various gynecologic cancer types, describing the development of the field from non-replicating adenoviral vectors to multiple-modified conditional replicating viruses. Transcriptional targeting of gynecologic cancer cells by the use of the promoter of vascular endothelial growth factor receptor type 1 (flt-1) was evaluated. Flt-1 is not expressed in the liver and thus an ideal promoter for transcriptional targeting of adenoviruses. Our studies implied that the flt-1 promoter is active in teratocarcinomas.and therefore a good candidate for development of oncolytic adenoviruses for treatment of this often problematic disease with then poor outcome. A tropism modified conditionally replicating adenovirus (CRAd), Ad5-Δ24RGD, was studied in gynecologic cancers. Ad5-Δ24RGD is an adenovirus selectively replication competent in cells defective in the p16/Rb pathway, including many or most tumor cells. The fiber of Ad5-Δ24RGD contains an integrin binding arginine-glycine-aspartic acid motif (RGD-4C), allowing coxackie-adenovirus receptor independent infection of cancer cells. This approach is attractive because expression levels of CAR are highly variable and often low on primary gynecological cancer cells. Oncolysis could be shown for a wide variety of ovarian and cervical cancer cell lines as well as primary ovarian cancer cell spheroids, a novel system developed for in vitro analysis of CRAds on primary tumor substrates. Biodistribution was evaluated and preclinical safety data was obtained by demonstrating lack of replication in human peripheral blood mononuclear cells. The efficicacy of Ad5-Δ24RGD was shown in different orthotopic murine models including a highly aggressive intraperitoneal model of disseminated ovarian cancer cells, where Ad5-Δ24RGD resulted in complete eradication of intraperitoneal disease in half of the mice. To further improve the selectivity and specificity of CRAds, triple-targeted oncolytic adenoviruses were cloned, featuring the cyclo-oxygenase-2 (cox-2) promoter, E1A transcomplementation and serotype chimerism. Those viruses were evaluated on ovarian cancer cells for specificity and oncolytic potency with regard to two different cox2 versions and three different variants of E1A (wild type, delta24 and delta2delta24). Ad5/3cox2Ld24 emerged as the best combination due to enhanced selectivity without potency lost in vitro or in an aggressive intraperitoneal orthotopic ovarian tumor model. In summary, the preclinical therapeutic efficacy of the CRAds tested in this study, taken together with promising biodistribution and safety data, suggest that these CRAds are interesting candidates for translation into clinical trials for gynecologic cancer.
  • Raki, Mari (Helsingin yliopisto, 2009)
    Virotherapy, the use of oncolytic properties of viruses for eradication of tumor cells, is an attractive strategy for treating cancers resistant to traditional modalities. Adenoviruses can be genetically modified to selectively replicate in and destroy tumor cells through exploitation of molecular differences between normal and cancer cells. The lytic life cycle of adenoviruses results in oncolysis of infected cells and spreading of virus progeny to surrounding cells. In this study, we evaluated different strategies for improving safety and efficacy of oncolytic virotherapy against human ovarian adenocarcinoma. We examined the antitumor efficacy of Ad5/3-Δ24, a serotype 3 receptor-targeted pRb-p16 pathway-selective oncolytic adenovirus, in combination with conventional chemotherapeutic agents. We observed synergistic activity in ovarian cancer cells when Ad5/3-Δ24 was given with either gemcitabine or epirubicin, common second-line treatment options for ovarian cancer. Our results also indicate that gemcitabine reduces the initial rate of Ad5/3-Δ24 replication without affecting the total amount of virus produced. In an orthotopic murine model of peritoneally disseminated ovarian cancer, combining Ad5/3-Δ24 with either gemcitabine or epirubicin resulted in greater therapeutic benefit than either agent alone. Another useful approach for increasing the efficacy of oncolytic agents is to arm viruses with therapeutic transgenes such as genes encoding prodrug-converting enzymes. We constructed Ad5/3-Δ24-TK-GFP, an oncolytic adenovirus encoding the thymidine kinase (TK) green fluorescent protein (GFP) fusion protein. This novel virus replicated efficiently on ovarian cancer cells, which correlated with increased GFP expression. Delivery of prodrug ganciclovir (GCV) immediately after infection abrogated viral replication, which might have utility as a safety switch mechanism. Oncolytic potency in vitro was enhanced by GCV in one cell line, and the interaction was not dependent on scheduling of the treatments. However, in murine models of metastatic ovarian cancer, administration of GCV did not add therapeutic benefit to this highly potent oncolytic agent. Detection of tumor progression and virus replication with bioluminescence and fluorescence imaging provided insight into the in vivo kinetics of oncolysis in living mice. For optimizing protocols for upcoming clinical trials, we utilized orthotopic murine models of ovarian cancer to analyze the effect of dose and scheduling of intraperitoneally delivered Ad5/3-Δ24. Weekly administration of Ad5/3-Δ24 did not significantly enhance antitumor efficacy over a single treatment. Our results also demonstrate that even a single intraperitoneal injection of only 100 viral particles significantly increased the survival of mice compared with untreated animals. Improved knowledge of adenovirus biology has resulted in creation of more effective oncolytic agents. However, with more potent therapy regimens an increase in unwanted side-effects is also possible. Therefore, inhibiting viral replication when necessary would be beneficial. We evaluated the antiviral activity of chlorpromazine and apigenin on adenovirus replication and associated toxicity in fresh human liver samples, normal cells, and ovarian cancer cells. Further, human xenografts in mice were utilized to evaluate antitumor efficacy, viral replication, and liver toxicity. Our data suggest that these agents can reduce replication of adenoviruses, which could provide a safety switch in case of replication-associated side-effects. In conclusion, we demonstrate that Ad5/3-Δ24 is a useful oncolytic agent for treatment of ovarian cancer either alone or in combination with conventional chemotherapeutic drugs. Insertion of genes encoding prodrug-converting enzymes into the genome of Ad5/3-Δ24 might not lead to enhanced antitumor efficacy with this highly potent oncolytic virus. As a safety feature, viral activity can be inhibited with pharmacological substances. Clinical trials are however needed to confirm if these preclinical results can be translated into efficacy in humans. Promising safety data seen here, and in previous publications suggest that clinical evaluation of the agent is feasible.
  • Rajecki, Maria (Helsingin yliopisto, 2011)
    Prostate cancer is the most common cancer in males. Although many patients with localized disease can be cured with surgery and radiotherapy, advanced disease and especially castration resistant metastatic disease remains incurable, with a median life expectancy of less than 18 months. Oncolytic adenoviruses (Ads) are a new promising treatment against cancer due to their innate capacity to kill cancer cells. Viral replication in tumor cells leads to oncolysis and production of a multiplicity of new virions that are capable of further destroying cancerous tissue. Oncolytic Ads can be modified for tumor targeted infection and replication and be armed with therapeutic transgenes to maximize the oncolytic effect. Worldwide, clinical trials with oncolytic Ads have demonstrated good safety while the antitumor efficacy remains to be improved. Importantly, the best responses have been reported when oncolytic adenoviruses have been combined with standard cancer treatments, such as chemotherapy and radiation. Further, a challenge in many virotherapy approaches has been the monitoring of virus replication in vivo. Reporter genes have been extensively used as transgenes to evaluate the biodistribution of the virus and activity of specific promoters. However, these techniques are often limited to preclinical evaluation and not amenable to human use. The aim of the thesis was to find and develop new oncolytic Ads with maximum efficacy against metastatic, castration resistant prostate cancer and study them in vitro and in vivo combined to different forms of radiation therapy. Using combination therapy, we were aiming for better antitumor efficacy with reduced side effects. Capsid modified Ads for enhanced transduction were studied. Serotype 3 targeted chimera, Ad5/3, was found to have enhanced infectivity for prostate cancer and was used for developing new viruses for the study. Correlation between Ad-encoded marker peptide secretion and simultaneous viral replication was evaluated and the effects of radiotherapy on viral replication were studied in detail. We found that the repair of double strand breaks caused by ionizing radiation was inhibited by adenoviral proteins and led to autophagic cell death. Both subcutaneous models and intrapulmonary tumor models mimicking metastatic, aggressive disease were used in vivo. Virus efficacy was evaluated by intratumoral injections. Also, intravenous administration was evaluated to study the effectiveness in metastatic disease. Oncolytic adenovirus treatment led to significant tumor growth control and increased the survival rate of the mice. These results were further improved when oncolytic Ads were combined with radiation therapy. Oncolytic Ads expressing human sodium/iodide transporter (hNIS) as a transgene were evaluated for their oncolytic potency and for the functionality of hNIS in vitro and in vivo. Monitoring of viral replication was also assessed using different imaging modalities relative to clinical use. SPECT imaging of tumor-bearing mice was evaluated and combined with simultaneous CT-scanning to obtain important anatomical information on biodistribution, also in a three-dimensional form. It was shown that hNIS-expressing adenoviruses could harbour a bi-functional transgene allowing for localization and imaging of viral replication. Targeted radiotherapy was applied by systemic radioiodide administration and resulted in iodide accumulation into Ad-infected tumor. The combination treatment showed significantly enhanced antitumor efficacy in mice bearing prostate cancer tumors. In summary, the results presented above aim to provide new treatment modalities for castration resistant prostate cancer. Molecular insights were provided for better understanding of the benefits of combined radiation therapy and oncolytic adenoviruses, which will hopefully facilitate the translation of the approach into clinical use for humans.
  • Vainio, Annukka (Helsingin yliopisto, 2003)
  • Ojell, Ari (Helsingin yliopisto, 2007)
    The thesis consists of five international congress papers and a summary with an introduction. The overarching aim of the studies and the summary is to examine the inner coherency of the theological and anthropological thinking of Gregory of Nyssa (331-395). To the issue is applied an "apophatic approach" with a "Christological focus". It is suggested that the coherency is to be found from the Christological concept of unity between "true God" and "true man" in the one person of Jesus Christ. Gregory is among the first to make a full recognition of two natures of Christ, and to use this recognition systematically in his writings. The aim of the studies is pursued by the method of "identification", a combination of the modern critical "problematic method" and Gregory's own aphairetic method of "following" (akolouthia). The preoccupation with issues relating to the so-called Hellenization of Christianity in the patristic era was strong in the twentieth-century Gregory scholarship. The most discussed questions have been the Greek influence in his thought and his philosophical sources. In the five articles of the thesis it is examined how Gregory's thinking stands in its own right. The manifestly apophatic character of his theological thinking is made a part of the method of examining his thought according to the principles of his own method of following. The basic issue concerning the relation of theology and anthropology is discussed in the contexts of his central Trinitarian, anhtropological, Christological and eschatological sources. In the summary the Christocentric integration of Gregory's thinking is discussed also in relation to the issue of the alledged Hellenization. The main conclusion of the thesis concerns the concept of theology in Gregory. It is not indebted to the classical concept of theology as metaphysics or human speculation of God. Instead, it is founded to the traditional Judeo-Christian idea of God who speaks with his people face to face. In Gregory, theologia connotes the oikonomia of God's self-revelation. It may be regarded as the state of constant expression of love between the Creator and his created image. In theology, the human person becomes an image of the Word by which the Father expresses his love to "man" whom he loves as his own Son. Eventually the whole humankind, as one, gives the divine Word a physical - audible and sensible - Body. Humankind then becomes what theology is. The whole humanity expresses divine love by manifesting Christ in words and deeds, singing in one voice to the glory of the Father, the Son and the Holy Spirit.
  • Rusanen, Anna-Mari (Helsingin yliopisto, 2014)
    One task of cognitive science is to explain the information processing capacities of cognitive systems, and to provide a scientific account of how cognitive systems produce the adaptive and systematic intelligent behavior that they do. However, there are several disputes and controversies among cognitive scientists about almost every aspect of the question of how to fulfill this task. Some of these disputes originate from the fundamental issue of how to explain cognitive phenomena. In recent years, a growing number of philosophers have proposed that explanations of cognitive phenomena could be seen as instances of mechanistic explanation. In this dissertation, my aim is to examine to what extent the mechanistic account of explanation can be applied to explanations of complex cognitive phenomena, such as conceptual change. The dissertation is composed of five related research articles, which explore different aspects of mechanistic explanations. The first two articles explore the question, whether explanations of cognitive phenomena are mechanistic in the standard sense. The third and fourth articles focus on two widely shared assumptions concerning the mechanistic account of explanatory models: that (i) explanatory models represent, describe, correspond to or are similar to mechanisms in the world and that (ii) in order to be explanatory a model must represent the relevant causal or constitutive organization of a mechanism in the world. Finally, in the fifth article a sketch of a mechanistic explanation of conceptual change is outlined. The main conclusions of this dissertation can be summarized as four distinct, but related claims: (i) I argue that the standard mechanistic account of explanation can be applied to such cognitive explanations which track dependencies at the performance level. Those explanations refer to mechanisms which sustain or perform cognitive activity. However, (ii) if mechanistic explanations are extended to cover so-called computational or competence level explanations as well, a more liberal interpretation of the term mechanism may be needed (Rusanen and Lappi 2007; Lappi abd Rusanen 2011). Moreover (iii) it is also argued that computational or competence level explanations are genuinely explanatory, and that they are more than mere descriptions of computational tasks. Rather than describing the causal basis of certain performances of the target system, or how that system can have certain capacities or competences, they explain why and how certain principles govern the possible behavior or processes of the target system. Finally, (iv) I propose that the information semantic account of representational character of scientific models can offer a naturalist account of how models depict can depict their targets, and offer also an objective account of how explanatory models can depict the relevant properties of their target systems (Rusanen and Lappi 2012; Rusanen under review).
  • Yang, Fan (Helsingin yliopisto, 2014)
    Dependence logic is a new logic which incorporates the notion of dependence , as well as independence between variables into first-order logic. In this thesis, we study extensions and variants of dependence logic on the first-order, propositional and modal level. In particular, the role of intuitionistic connectives in this setting is emphasized. We obtain, among others, the following results: 1. First-order intuitionistic dependence logic is proved to have the same expressive power as the full second-order logic. 2. Complete axiomatizations for propositional dependence logic and its variants are obtained. 3. The complexity of model checking problem for modal intuitionistic dependence logic is analyzed.
  • Hirsikko, Anne (Helsingin yliopisto, 2011)
    Aerosol particles have effect on climate, visibility, air quality and human health. However, the strength of which aerosol particles affect our everyday life is not well described or entirely understood. Therefore, investigations of different processes and phenomena including e.g. primary particle sources, initial steps of secondary particle formation and growth, significance of charged particles in particle formation, as well as redistribution mechanisms in the atmosphere are required. In this work sources, sinks and concentrations of air ions (charged molecules, cluster and particles) were investigated directly by measuring air molecule ionising components (i.e. radon activity concentrations and external radiation dose rates) and charged particle size distributions, as well as based on literature review. The obtained results gave comprehensive and valuable picture of the spatial and temporal variation of the air ion sources, sinks and concentrations to use as input parameters in local and global scale climate models. Newly developed air ion spectrometers (Airel Ltd.) offered a possibility to investigate atmospheric (charged) particle formation and growth at sub-3 nm sizes. Therefore, new visual classification schemes for charged particle formation events were developed, and a newly developed particle growth rate method was tested with over one year dataset. These data analysis methods have been widely utilised by other researchers since introducing them. This thesis resulted interesting characteristics of atmospheric particle formation and growth: e.g. particle growth may sometimes be suppressed before detection limit (~ 3 nm) of traditional aerosol instruments, particle formation may take place during daytime as well as in the evening, growth rates of sub-3 nm particles were quite constant throughout the year while growth rates of larger particles (3-20 nm in diameter) were higher during summer compared to winter. These observations were thought to be a consequence of availability of condensing vapours. The observations of this thesis offered new understanding of the particle formation in the atmosphere. However, the role of ions in particle formation, which is not well understood with current knowledge, requires further research in future.
  • Pauna, Matti (Helsingin yliopisto, 2007)
    In this thesis we study a few games related to non-wellfounded and stationary sets. Games have turned out to be an important tool in mathematical logic ranging from semantic games defining the truth of a sentence in a given logic to for example games on real numbers whose determinacies have important effects on the consistency of certain large cardinal assumptions. The equality of non-wellfounded sets can be determined by a so called bisimulation game already used to identify processes in theoretical computer science and possible world models for modal logic. Here we present a game to classify non-wellfounded sets according to their branching structure. We also study games on stationary sets moving back to classical wellfounded set theory. We also describe a way to approximate non-wellfounded sets with hereditarily finite wellfounded sets. The framework used to do this is domain theory. In the Banach-Mazur game, also called the ideal game, the players play a descending sequence of stationary sets and the second player tries to keep their intersection stationary. The game is connected to precipitousness of the corresponding ideal. In the pressing down game first player plays regressive functions defined on stationary sets and the second player responds with a stationary set where the function is constant trying to keep the intersection stationary. This game has applications in model theory to the determinacy of the Ehrenfeucht-Fraisse game. We show that it is consistent that these games are not equivalent.
  • Kuusinen, Riitta (Helsingin yliopisto, 2001)
    Tutkimuksessa analysoidaan teoriatasolla web-avusteisen tiedontuottamisyhteistyön kokeilutoiminnassa esiin tulleita ongelmia ja kootaan niiden viitoittamana teoriaperustaa tulevaisuuden työskentelytavalle, tietämyksen web-avusteiselle ryhmäprosessoinnille. Keskiössä on ihminen kognitiivisena tiedonkäsittelijänä ja elinikäisenä oppijana. Organisaatiossa vallitsevat toimintastrategiat, ryhmätyöskentelyn organisointi ja ryhmässä toteutuvat käytännöt muodostavat yksilön toimintaa ohjaavan sosiaalisen toimintaympäristön, joka säätelee yhteistyöprosessin onnistumista. Yhteistyötä tarkastellaan sosiaalisen tiedonkäsittelyn ryhmäilmiönä, jossa käsite yhteistyökyky kyseenalaistuu. Tuotetussa teoriaperustassa ihminen nähdään monitasoisten oppimishaasteiden ristitulessa. Koulutuksessa vallitseva absoluuttinen tietokäsitys on pystyttävä muuttamaan konstruktivistiseksi tietokäsitykseksi: yhteistä tietämystä ryhmänä tuotettaessa yksilöiden tietämys on rakennusaineena. Koulussa saatu sosiaalisen tiedonkäsittelyn malli, itsekeskeisen tiedonkäsittelyn malli, ei sovellu tietämyksen ryhmäprosessointiin. Malliin liittyviä oppeja on poisopittava samalla kun ryhmäjäsenenä on suunniteltava ja yhdessä opeteltava ryhmäkeskeisiä ja web-avusteisia tiedonkäsittelymalleja. Näin yhteistyöprosessissa toteutuu rinnakkain asiaoppimista ja toimintaoppimista. Näitä molempia on tarpeen tukea kehitettäessä uudenlaisia web-avusteisia työskentelymenetelmiä. Osassa I esitellään tutkimuksen kokemusperäisiä virikkeitä. Suhteellisen tietokäsityksen mukaisesti tämä tutkimus on kiinteästi kytkeytynyt tutkijan elinikäiseen oppimiseen ja tutkimus kuvataan tutkijan yksilöllisen tietämyksen prosessointina. Tutkimusaiheen löytymiseen johtaneet käytännön havainnot aloittavat sen takia raportoinnin. Erityisesti koulun sosiaalisen tiedonkäsittelyn organisointi on tarkastelun kohteena. Osassa II hahmotetaan tutkimusnäkökulmaa. Tutkimuskysymykset ovat lähinnä viitoittamassa tietämyksen etsintää. Tutkimusmenetelmä, kokeilutoiminnan analysointi, on saanut vahvasti vaikutteita toimintatutkimuksesta. Tutkimusasetelman perustana on toimintaan kytkeytyvä ihmiskäsitys. Kirjallisuuden avulla etsitään mahdollisia kytkeytymiä ihmisen käyttäytymisen ja sosiaalisen toiminnan organisoinnin välillä. Osa III kuvailee tutkimusaihetta koskevan ymmärryksen prosessointia. Esiymmärrys yhteistyöstä ja yhteistyökäsitteen määrittely mahdollistavat kokeilutoimintaan ryhtymisen. Uusi viestintämahdollisuus (www) nähdään yhteisessä tiedonkäsittelyssä apuvälineenä. Käytännön kokeilujaksot tarjoavat aineksia kognitiivisen tiedonkäsittelyn syvällisten periaatteiden löytymiselle. Inhimillinen toiminta ja sosiaalinen tiedonkäsittely saavat teoriatason analysoinnissa oppimiseen perustuvia tulkintoja. Osassa IV esitellään tutkimuksen tavoitteena ollutta teoriaperustaa tietämyksen web-avusteiselle ryhmäprosessoinnille. Teoriatiivistelmässä keskiöön nousee ihmisen kognitiivinen tiedonkäsittely sekä konstruktivistisen asiaoppimisen että selviytymispainotteisen toimintaoppimisen muodossa. Sosiaalinen toimintaympäristö nähdään osallisena kognitiivisessa tiedonkäsittelyssä ja selityksenä sille, että yhteinen tiedonkäsittely ei onnistu pelkästään tietoverkkoympäristössä vaan tarvitaan myös sosiaalisia tapaamisia. Kokeilutoiminnan opetuksia tuodaan esille yhteistyöprosessin keskeisten tapahtumien tarkastelussa. Tuotettua teoriaperustaa koetellaan tieteen kentällä vertailemalla sitä muiden tutkijoiden julkaisemiin käsityksiin. Tietoverkkoteknologian suhdetta inhimilliseen tiedonkäsittelyyn verrataan muualla saatuihin ja julkaistuihin käsityksiin. Avainsanat: tietointensiivinen yhteistyö, tiedontuottamisyhteistyö, yhteistyöprosessi, yhteistyökyky, yhteistyökyvyttömyys, virtuaalinen yhteistyöorganisaatio, yksilöllinen tietämys, yhteisen ymmärryksen etsintä, yhteinen tietämys, kognitiivinen tiedonkäsittely, asiaoppiminen, toimintaoppiminen, sosiaalinen tiedonkäsittely, sosiaalinen toimintaympäristö, automatisoitunut toimintamalli, yksilökeskeinen toimintamalli, itsekeskeinen toimintamalli, ryhmäkeskeinen toimintamalli, sosiaalisen tiedonkäsittelyn toimintastrategia, työympäristössä oppiminen.
  • Nikula, Miika (Helsingin yliopisto, 2014)
    Mandelbrot cascades and multiplicative chaos are two related natural constructions of random multifractal measures, or rather families of such measures indexed by a single real parameter. While these models were first defined decades ago, they have recently become topical again after they were applied in the field of planar random geometry. In that context, multiplicative chaos provides one rigorous way of defining the exponential of the Gaussian free field. Typically, for a Mandelbrot cascade or multiplicative chaos there exists a critical parameter value at which the behavior of the measure changes drastically. Away from criticality, the geometric properties of cascade and chaos measures have been studied intensively and much of the theory is by now classical. For small values of the parameter, the random measures considered here are natural examples of multifractality. The measures are exact dimensional with the dimension, depending deterministically on the parameter, strictly between 0 and the dimension of the ambient space in which the measure is constructed. For large values of the parameter the construction of the measures is a rather subtle issue, but it is known that in this case the measures are atomic. The main theme of this dissertation is the study of geometric properties of cascade and chaos measures at the critical parameter value. To mention one main result, it is shown that while the critical measures are almost surely supported on sets of Hausdorff dimension 0, they do not have atoms. Improving on the qualitative result, almost sure quantitative bounds are given for the mass carried by a set of a given size in the ambient geometry. One part of the analysis of the geometric properties of cascade and chaos measures is understanding the probability distributions of the mass of a given set. Since the measures are built to exhibit strong statistical self-similarity, this is a major part of understanding the full law of the measure, i.e. the joint laws arbitrary collections of sets. Results concerning the law of the mass of a fixed set are another main theme of this dissertation.
  • Gritsenko, Daria (Helsingin yliopisto, 2014)
    This dissertation aims at clarifying how multiple public and private decision-making actors co-exist in the governing of shipping quality in the Baltic Sea, and which mechanisms allow these multiactor arrangements to proliferate and sustain themselves. Acknowledging that collective action problems undermine quality governance, this research sought to collect empirical evidence documenting the role of polycentricity, which implies the existence of overlapping and competing centers of decision making embedded within multiple interdependent and often conflicting contexts, for quality shipping and the way it is conceptualized, operationalized, and practiced. A key argument in this thesis is that whereas the shipping industry is global, quality shipping governance is not; therefore, quality shipping governance takes a form of contextually-bound steering. Quality shipping is defined in this research as shipping that aims at safety and environmental protection, while still maintaining economic sustainability. The two central aspect of quality in shipping safety and environmental were used to empirically grasp and operationalize quality shipping in four individual studies conducted within this dissertation project. The individual empirical studies do not build upon each other directly, however they are linked thematically, conceptually, and methodologically, and allow for interconnected, though varying insights on the emergence and development of collective action by revealing how the practices associated with quality shipping were defined and materialized. The empirical research was built upon reconstructing the governance process on the basis of methodological localism , that is, focusing on actors who are involved in the process of steering, their interactions, and how institutions structure the interaction within multiple interconnected contexts in which interactions are embedded. This thesis relates to the wider body of research on governance by focusing on how quality shipping governance cuts across different levels and jurisdictions and penetrates the grey zones in which neither markets nor states can solely solve collective action problems. Reflecting on the impact of multiactor interaction that connects different functionalities and localities, it contributes to four interconnected theoretical debates on governance: on the role of politics and power, on the territorial dimension of boundary-spanning governance, on the new role images and dilemmas, and on governing of governance, or metagovernance. This dissertation makes an empirical argument to support the proposition that quality shipping governance is not a technical depoliticized process of problem-fixing, but a battlefield overrun with power struggles and conflicts over resources, images, and institutions. The four individual studies portray much of the interaction in existing quality shipping governance as informal and ad hoc, and emphasize that everyday inter-organizational exchanges constitute the larger part of interactions between shipping actors in governance of quality shipping. It further speculates about the role of metagovernance and interactions that allow actors to establish mechanisms that link vertical (hierarchical) and horizontal (market and network) dimensions of governance. The thesis claims that if we want more quality shipping, we need to be able to explain and master the connecting relation between actors and institutions that enhance multiactor coordination and make collaboration work. The practical contribution of this study is in elaborating a framework for formulation and implementation of socio-economic innovation for balanced development and public well-being in polycentric contexts using the example of quality shipping governance. The focus on concrete instances of collective action in quality shipping governance in the Baltic Sea demonstrates that interactions, institutions and mechanisms vary in time and space. This finding has important implications for solving social and environmental challenges in arenas other than shipping, because it shows that collective action is contextually-bound and that local solutions can be found to problems conventionally identified as global.
  • Lehtomaa, Jaakko (Helsingin yliopisto, 2016)
    This book is about heavy-tailed random variables and the phenomena they induce to mathematical models. It has become clear that the classical models employing light-tailed variables have an inherent tendency to underestimate the magnitude of extremal events. Recent developments in the financial world (financial crises) suggest that such shortcomings are not merely theoretical curiosities, but game-changing phenomena that can solely determine the fate of an agent. To overcome the obstacles set by the classical lines of thought an agent must consider ways to improve the way risk is modelled and assessed. The book proposes two ways to do this. Firstly, the existing models are reconfigured to include the effects of different types of risks. Secondly, heavy-tailed effects such as the principle of a single big jump are made more transparent by a detailed investigation. The mathematical theory of this book is based on the theory of random walks and their generalisations. Special attention is paid to randomly weighted random walks and randomly stopped random walks that are commonly encountered in the field of insurance mathematics.
  • Järvinen, Riku (Helsingin yliopisto, 2011)
    This doctoral thesis is about the solar wind influence on the atmosphere of the planet Venus. A numerical plasma simulation model was developed for the interaction between Venus and the solar wind to study the erosion of charged particles from the Venus upper atmosphere. The developed model is a hybrid simulation where ions are treated as particles and electrons are modelled as a fluid. The simulation was used to study the solar wind induced ion escape from Venus as observed by the European Space Agency's Venus Express and NASA's Pioneer Venus Orbiter spacecraft. Especially, observations made by the ASPERA-4 particle instrument onboard Venus Express were studied. The thesis consists of an introductory part and four peer-reviewed articles published in scientific journals. In the introduction Venus is presented as one of the terrestrial planets in the Solar System and the main findings of the work are discussed within the wider context of planetary physics. Venus is the closest neighbouring planet to the Earth and the most earthlike planet in its size and mass orbiting the Sun. Whereas the atmosphere of the Earth consists mainly of nitrogen and oxygen, Venus has a hot carbon dioxide atmosphere, which is dominated by the greenhouse effect. Venus has all of its water in the atmosphere, which is only a fraction of the Earth's total water supply. Since planets developed presumably in similar conditions in the young Solar System, why Venus and Earth became so different in many respects? One important feature of Venus is that the planet does not have an intrinsic magnetic field. This makes it possible for the solar wind, a continuous stream of charged particles from the Sun, to flow close to Venus and to pick up ions from the planet's upper atmosphere. The strong intrinsic magnetic field of the Earth dominates the terrestrial magnetosphere and deflects the solar wind flow far away from the atmosphere. The region around Venus where the planet's atmosphere interacts with the solar wind is called the plasma environment or the induced magnetosphere. Main findings of the work include new knowledge about the movement of escaping planetary ions in the Venusian induced magnetosphere. Further, the developed simulation model was used to study how the solar wind conditions affect the ion escape from Venus. Especially, the global three-dimensional structure of the Venusian particle and magnetic environment was studied. The results help to interpret spacecraft observations around the planet. Finally, several remaining questions were identified, which could potentially improve our knowledge of the Venus ion escape and guide the future development of planetary plasma simulations.