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  • Salovaara, Antti (Helsingin yliopisto, 2012)
    Vaikka vuorovaikutteiset teknologiat yleensä kehitetään ennalta mietittyihin käyttötarkoituksiin, käyttäjät usein muokkaavat niitä omiin tarpeisiinsa sopiviksi. Tätä käyttötapoja muuttavaa muokkaamisprosessia kutsutaan appropriaatioksi. Appropriaatio on sekä sosiaalinen että kognitiivinen prosessi. Sen sosiaalisia piirteistä on tutkittu mm. teknologiakäytäntöjen muuttumista ja oppimista sekä appropriaatioita levittävien avainyksilöiden toimintaa. Sitä vastoin kognitiivisia piirteitä on tutkittu vähän. Tässä väitöskirjassa kehitään teoriaa appropriaatioille, joissa yksilöt keksivät teknologioille uusia, heille aiemmin tuntemattomia käyttötarkoituksia (repurposive appropriations). Erityisesti keskitytään kiertotapoihin (workarounds): tehtävätilanteisiin, joissa käyttäjä keksii korvata aiemman kokemuksensa pohjalta tutuksi tulleen teknologian toisella teknologialla, jonka hän ei ole aiemmin mieltänyt liittyvän kyseiseen tehtävään. Tämä väitöskirja on tutkimusotteeltaan eksploratiivinen. Se pohjautuu kognitiotieteeseen, erityisesti hajautetun kognition, ongelmanratkaisun ja luovuuden tutkimukseen. Empiirisenä pohjana on kolme kenttätutkimusta langattomista multimediaviestintäjärjestelmistä (mGroup, CoMedia ja Comeks) sekä www-kysely digitaalikameroiden käytöstä. Yhteistä näille teknologioille on arkikäyttö institutionaalisen kontekstin ulkopuolella ja se, että niillä tuotetaan visuaalista sisältöä pieninä kokonaisuuksina ilman korkean tason teknistä asiantuntemusta, esim. ohjelmointitaitoa. Väitöskirja ehdottaa, että approprioidessaan yksilö muodostaa mielessään uudenlaisen kytkennän (mapping) teknologisten, sosiaalisten ja fyysisten tilannetekijöiden välille. Näin hän oppii uuden ratkaisumallin (solution schema) teknologian käyttötavasta. Väitöskirja esittää kolme kognitiivista kytkemisprosessia, joilla voidaan selittää kiertotapojen kaltaisia appropriaatioita. Kytkemisistä ensimmäinen vaihtoehtoinen prossessi perustuu osittaisten ratkaisumallien tunnistamiseen yksilön ympäristössä. Muut kaksi perustuvat analogioiden tunnistamiseen ratkaisutapojen tai ratkaisuun sopivien välineiden välillä. Väitöskirja ehdottaa, että käyttäjien aiempi teknologinen asiantuntemus edesauttaa näitä kolmea kytkemisprosessia. Tulokset tarjoavat suunnittelusuosituksia ihmisen ja tietokoneen vuorovaikutuksen kehittämiseen sekä lähtökohtia uusiin kognitiotieteellisiin tutkimuksiin.
  • Siitonen, Paula (Helsingin yliopisto, 2003)
  • Ruoppila, Sampo (Helsingin yliopisto, 2006)
    The thesis examines urban issues arising from the transformation from state socialism to a market economy. The main topics are residential differentiation, i.e., uneven spatial distribution of social groups across urban residential areas, and the effects of housing policy and town planning on urban development. The case study is development in Tallinn, the capital city of Estonia, in the context of development of Central and Eastern European cities under and after socialism. The main body of the thesis consists of four separately published refereed articles. The research question that brings the articles together is how the residential (socio-spatial) pattern of cities developed during the state socialist period and how and why that pattern has changed since the transformation to a market economy began. The first article reviews the literature on residential differentiation in Budapest, Prague, Tallinn and Warsaw under state socialism from the viewpoint of the role of housing policy in the processes of residential differentiation at various stages of the socialist era. The paper shows how the socialist housing provision system produced socio-occupational residential differentiation directly and indirectly and it describes how the residential patterns of these cities developed. The second article is critical of oversimplified accounts of rapid reorganisation of the overall socio-spatial pattern of post-socialist cities and of claims that residential mobility has had a straightforward role in it. The Tallinn case study, consisting of an analysis of the distribution of socio-economic groups across eight city districts and over four housing types in 1999 as well as examining the role of residential mobility in differentiation during the 1990s, provides contrasting evidence. The third article analyses the role and effects of housing policies in Tallinn s residential differentiation. The focus is on contemporary post-privatisation housing-policy measures and their effects. The article shows that the Estonian housing policies do not even aim to reduce, prevent or slow down the harmful effects of the considerable income disparities that are manifest in housing inequality and residential differentiation. The fourth article examines the development of Tallinn s urban planning system 1991-2004 from the viewpoint of what means it has provided the city with to intervene in urban development and how the city has used these tools. The paper finds that despite some recent progress in planning, its role in guiding where and how the city actually developed has so far been limited. Tallinn s urban development is rather initiated and driven by private agents seeking profit from their investment in land. The thesis includes original empirical research in the three articles that analyse development since socialism. The second article employs quantitative data and methods, primarily index calculation, whereas the third and the fourth ones draw from a survey of policy documents combined with interviews with key informants. Keywords: residential differentiation, housing policy, urban planning, post-socialist transformation, Estonia, Tallinn
  • Sommarhem, Antti (Helsingin yliopisto, 2007)
    Rituximab, a monoclonal antibody against B-cell specific CD20 antigen, is used for the treatment of non-Hodgkin lymphomas (NHL) and chronic lymphatic leukemia. In combination with chemotherapeutics rituximab has remarkably improved the outcome of NHL patients, but a vast variation in the lengths of remissions remains and the outcome of individual patients is difficult to predict. This thesis has searched for an explanation for this by studying the effector mechanisms of rituximab and by comparing gene expression in lymphoma tissue samples of patients with long- and short-term survival. This work demonstrated that activation of complement (C) system is in vitro more efficient effector mechanism of rituximab than cellular mechanisms or apoptosis. Activation of the C system was also shown in vivo during rituximab treatment. However, intravenously administered rituximab could not enter the cerebrospinal fluid, and neither C activation nor removal of lymphoma cells was observed in central nervous system. In vitro cytotoxicity assays showed that rituximab-induced cell killing could be markedly improved with simultaneous neutralization of the C regulatory proteins CD46 (Membrane cofactor protein), CD55 (Decay-accelerating factor), and CD59 (protectin). In a retrospective study of follicular lymphoma (FL) patients, low lymphoma tissue mRNA expressions of CD59 and CD55 were associated with a good prognosis and in a progressive flow cytometry study high expression of CD20 relative to CD55 was correlated to a longer progression free survival. Gene expression profile analysis revealed that expression of certain often cell cycle, signal transduction or immune response related genes correlate with clinical outcome of FL patients. Emphasizing the role of tumor microenvironment the best differentiating genes Smad1 and EphA1 were demonstrated to be mainly expressed in the non-malignant cells of tumors. In conclusion, this thesis shows that activation of the C system is a clinically important effector mechanism of rituximab and that microenvironment factor in tumors and expression of C regulatory proteins affect markedly the efficacy of immunochemotherapy. This data can be used to identify more accurately the patients for whom immunochemotherapy is given. It may also be beneficial in development of rituximab-containing and other monoclonal antibody therapies against cancer.
  • Vuorinen, Anssi (Helsingin yliopisto, 2011)
    Peruna kestää A-virusta estämällä sen leviämistä Peruna on maissin ohella maailman kolmanneksi tärkein ravintokasvi vehnän ja riisin jälkeen. Perunaa lisätään kasvullisesti mukuloita istuttamalla, jolloin virukset siirtyvät sairaiden siemenmukuloiden välityksellä kasvukaudesta toiseen. Virustauteja voi torjua ainoastaan terveen siemenperunan ja kestävien lajikkeiden avulla. Kestävyys perustuu usein siihen, että kasvi estää viruksen leviämisen tartuntakohdasta välttyäkseen virustaudilta. Tässä työssä tutkittiin kolmea perunan A-viruksen (PVA) liikkumista estävää kestävyysmekanismia perunassa. Lisäksi työn kokeelliseen osaan oleellisesti kuuluvaa virustartutusta varten kehitettiin uusi paranneltu versio geenipyssystä. Tämä itse rakennettu laite optimoitiin PVA:n tartuttamiseen mahdollisimman helposti ja pienin käyttökustannuksin. Tutkimuksen kohteena olleessa perunan risteytysjälkeläistössä oli PVA:ta kestäviä kasveja (ryhmä nnr), jotka estivät viruksen liikkumisen aiheuttamatta oireita tartutuskohdassa, sekä kasveja, joissa PVA aiheutti kuolioläikkinä näkyvän yliherkkyysvasteen (ryhmä HR). Molemmissa kestävyystyypeissä virus pystyi monistumaan ja leviämään solusta soluun paikallisesti, mutta liikkuminen muihin kasvinosiin nilan kautta estyi. Ryhmän nnr kasveissa PVA-tartunta ei aiheuttanut tilastollisesti merkitsevää muutosta useimpien geenien ilmenemiseen tartuntakohdassa. Ainoastaan geeniperhe, joka ilmentää tiettyä proteinaasi-inhibiittoria (PI), reagoi PVA:han 24 tuntia tartutuksesta. Kun tämän PVA:han reagoivan geeniperheen jäsenet hiljennettiin nnr- perunalinjoissa, ne muuttuivat alttiiksi PVA:lle ja virus levisi tartuntakohdasta muihin kasvinosiin. Tulos osoittaa, että PI on viruskestävyystekijä. Lisäksi muut tutkimuksessa saadut tulokset tukevat mahdollisuutta, että PI estää PVA:n P1-proteinaasin toimintaa. HR-linjoissa todettiin erilaisiin puolustusvasteisiin liittyvien PR-geenien aktivoitumista PVA-tartunnan seurauksena, mutta myös ilman sitä kasvien kasvettua mullassa noin neljä viikkoa. Sen sijaan solukkoviljelyssä tai vasta kaksi viikkoa mullassa kasvaneissa kasveissa vastaavaa ei vielä todettu. Tulos viittaa siihen, että HR-perunat reagoivat herkemmin ympäristöön ja/tai kasvin kehitysasteeseen laukaisten puolustusvasteita, jotka saattavat parantaa kestävyyttä taudinaiheuttajia vastaan. Kolmas tutkittu kestävyystyyppi havaittiin Pito-perunalajikkeessa. Se muistutti nnr-kestävyyttä siten, että myös siinä viruksen liikkuminen nilassa muihin kasvinosiin estyi. PVA:n todettiin pysähtyvän vasta lehtiruodin tyvelle muodostuvaan irtoamisvyöhykkeeseen, mitä havainnollistettiin käyttämällä muunnettua PVA-rotua, joka tuotti UV-valossa fluoresoivaa vihreää valoa. Tulos viittaa siihen, että virus ei pääse kulkemaan vyöhykkeeseen kuuluvan suojaavan kerroksen läpi, jollei sillä ole pääsyä nilaan. Tällainen kestävyys on tarpeen, jotta virus ei voi korvata nilakuljetusta solusta soluun leviämisellä. Tulokset tuovat uusia näkökulmia kasvien viruskestävyyteen ja auttavat selittämään viruksen nilakuljetuksen estymistä sekä solusta soluun leviämisen pysähtymistä kestävissä kasveissa.
  • Vatanen, Anna (Helsingin yliopisto, 2014)
    This study examines overlapping talk in naturally occurring interaction by focusing on the social actions that are accomplished through both the overlapping and the overlapped turns with the aim of determining the motivation for early turn-onset. The focus is on the agreeing non-minimal responding turns that start up in overlap at a point that is not a transition relevance place, that is, in the middle of a turn, where not all projected elements have yet been produced. The data consist of such responding turns from seven hours of monolingual everyday face-to-face conversation in Finnish and Estonian. This study adopts the framework of conversation analysis, which is supplemented by interactional linguistics. The early-onset responses are rather uniform in the social action types they implement. While they affiliate and align with the overlapped initiating action, they all convey an aspect of independence in their epistemic access. Three different response types are attested in the data: (1) claims of similar knowledge and experience, (2) independent agreements and (3) demonstrations of understanding. The participants do not orient to these overlapping responses as being interruptive. The overlapped initiating actions belong to a previously understudied turn type, assertion. In assertion turns, the speaker asserts something concerning a rather general state of affairs, often attaching an evaluative, personal stance to it. Comparing the early-onset overlaps to other turn-onset types, it is shown that early response-onset is due to an aspect of epistemic independence in the turn rather than to the turn being in agreement with the prior one. In other words, epistemic factors are crucial in explaining the early response-onset. The motivation for this turn-onset type lies in the recipient s expression of equal commitment to the assertion being made. The recipient thus strives for a more balanced, symmetrical relationship between the participants with regard to both time (turn-onset point) and agency (rights to make the assertion). Early-onset overlap is shown to be a patterned practice for indicating strong agreement with an independent stance. The data suggest that in everyday conversations, participants do not invariably aim for no-gap-no-overlap; instead, the social action type also affects turn-taking practices. Patterned and legitimate turn transfer does not occur solely around transition relevance places but also elsewhere. The lack of completion of the prior/ongoing turn is exploited for the interactional purpose of implementing the responsive social action types that are attested here. The research results show no differences between the Finnish and Estonian conversations in terms of the phenomenon investigated here.
  • Nieminen, Tiina Maileena (Helsingin yliopisto, 2005)
  • Nissinen, Ari (Helsingin yliopisto, 1999)
  • Roitto, Marja (Helsingin yliopisto, 2006)
    The goal of this thesis was to examine the ecophysiological responses of Scots pine (Pinus sylvestris L.), with an emphasis on the oxidative enzyme peroxidase and plant phenolics to environmental stresses like elevated levels of nickel (Ni) and copper (Cu), and herbivory. The effects of Ni and Cu were studied in a gradient survey at a sulphur dioxide contaminated site in the Kola Peninsula, and with experiments in which seedlings were exposed to Ni mist or to Ni and Cu amended into the soil. In addition, experimental Ni exposure was combined with disturbance of the natural lichen cover of the forest ground layer. Pine sawfly attack was simulated in the early season defoliation experiment, in which mature Scots pine were defoliated (100 %) during two successive years in a dry, nutrient-poor Scots pine stand. In addition, the effect of previous defoliation on the growth of sawfly (Diprion pini L.) larvae was studied. Apoplastic peroxidase activity was elevated in the needles of pine in a Ni- , Cu- and SO2- polluted environment, which indicated an increased oxidative stress. Increased foliar peroxidase activity due to Ni contamination was shown in the experiment, in which Ni was added as mist. No such response was found in peroxidase acitivity of the roots exposed to elevated Ni and/or Cu in the soil. Elevated Ni in the soil increased the concentration of foliar condensed tannins, which are able to bind heavy metals in the cells. Addition of low levels of Ni in the soil appeared to benefit pine seedlings, which was seen as promoted shoot growth and better condition of the roots. Wet Ni deposition of 2000 mg m-2 reduced growth and survival of pine seedlings, whereas deposition levels 200 mg m-2 or 20 mg m-2 caused no effects in a 2-y lasting experiment. The lichen mat on the forest floor did not act as an effective buffer against the adverse impacts of heavy metals on pine seedlings. However, some evidence was found indicating that soil microbes profited from the lichen mat. Artificial defoliation increased peroxidase activity in the Scots pine needles. In addition, defoliation decreased nitrogen, diamine putrescine and glucose concentrations in the needles and increased the concentrations of several phenolic compounds, starch and sucrose. Previous artificial defoliation led to poor growth of sawfly larvae reared on the pines, suggesting delayed induced resistance in Scots pine. However, there was no consistent relationship between inducibility (proportional increase in a compound following defoliation) and adverse effects on the growth of pine sawfly larvae. The observed inducible responses in needle phenolics due to previous defoliation thus appear to represent non-specific responses against sawflies.
  • Rajala, Tiina (Helsingin yliopisto, 2008)
    In boreal forests, microorganisms have a pivotal role in nutrient and water supply of trees as well as in litter decomposition and nutrient cycling. This reinforces the link between above-ground and below-ground communities in the context of sustainable productivity of forest ecosystems. In northern boreal forests, the diversity of microbes associated with the trees is high compared to the number of distinct tree species. In this thesis, the aim was to study whether conspecific tree individuals harbour different soil microbes and whether the growth of the trees and the community structure of the associated microbes are connected. The study was performed in a clonal field trial of Norway spruce, which was established in a randomized block design in a clear-cut area. Since out-planting in 1994, the spruce clones showed two-fold growth differences. The fast-growing spruce clones were associated with a more diverse community of ectomycorrhizal fungi than the slow-growing spruce clones. These growth performance groups also differed with respect to other aspects of the associated soil microorganisms: the species composition of ectomycorrhizal fungi, in the amount of extraradical fungal mycelium, in the structure of bacterial community associated with the mycelium, and in the structure of microbial community in the organic layer. The communities of fungi colonizing needle litter of the spruce clones in the field did not differ and the loss of litter mass after two-years decomposition was equal. In vitro, needles of the slow-growing spruce clones were colonized by a more diverse community of endophytic fungi that were shown to be significant needle decomposers. This study showed a relationship between the growth of Norway spruce clones and the community structure of the associated soil microbes. Spatial heterogeneity in soil microbial community was connected with intraspecific variation of trees. The latter may therefore influence soil biodiversity in monospecific forests.
  • Palotie, Ulla (Helsingin yliopisto, 2009)
    This study aimed at elucidating real-life aspects of restorative treatment practices. In addition, dentists' views and perceptions of and variation in restorative treatment practices with respect to dentist-related factors were evaluated. Reasons for placement and replacement of restoration, material selection, posterior restoration longevity, and the use of local anesthesia were assessed on two cross-sectional data sets. Data from the Helsinki Public Dental Service (PDS) included details on 3057 restorations performed by dentists (n=134) during routine clinical work in 2001. The other PDS data from Vantaa were based on 205 patient records of young adults containing information on 1969 restorations investigated retrospectively from 1994-1996 backwards; 51 dentists performed the restorations. In addition, dentists’ self-reported use of local anesthesia and estimates of restoration longevity were investigated by means of a nationwide questionnaire sent to 592 general dental practitioners selected by systematic sampling from the membership list of the Finnish Dental Association in 2004. All data sets included some background information on dentists such as gender, year of birth or graduation, and working sector. In PDS in 2001, primary caries was the reason for placement of restoration more often among patients aged under 19 years than among older patients (p<0.001). Among patients over 36 years of age, replacements represented the majority. Regarding dentist-related factors, replacements of restorations were made by younger dentists more frequently than by older dentists (p<0.001). In PDS in 1994-1996, the replacement rate of posterior restorations was greater among female dentists than among male dentists (p=0.01), especially for amalgams (p=0.008). The mean age of replaced posterior restoration among young adults was 8.9 (SD 5.2) years for amalgam and 2.4 (SD 1.4) years for tooth-colored restorations, the actual replacement rate for all existing posterior restorations being 7% in PDS in 1994-1996. Of all restorative materials used, a clear majority (69%) were composites in PDS in 2001. Local anesthesia was used in 48% of cases and more frequently for older patients (55%) than for patients aged under 13 years (35%) (p<0.001). Younger dentists more often used local anesthesia for primary restoration than did the older dentists (p<0.001), especially for primary teeth (p=0.005). Working sector had an impact on dentists’ self-reported use of local anesthesia and estimates of restoration longevity; public sector dentists reported using local anesthesia more frequently than private sector dentists for Class II (p=0.04) and for Class III restorations (p=0.01). Private sector dentists gave longer estimates of posterior composite longevity than public sector dentists (p=0.001). In conclusion, restorative treatment practices seem to vary according to patient age and also dentist-related factors. Replacements of restorations are common for adults. For children, clear underuse of local anesthesia prevails.
  • Reyes Gomez, Javier Alberto (2014)
    Law & Economics is the hegemonic framework in mainstream corporate governance theory and praxis. It permeates how legal scholars see corporations, how they must be managed, and to which ends they should be geared to. Because large amount of power is concentrated and exercised through corporations, the fact that law & economics is both a descriptive and a normative theory has an impact on the shaping of the world. This research aims at asking: is there an alternative normative jurisprudence to law & economics in corporate governance? In order to approach this task, the methodology used is hybrid, leaning towards a hermeneutical qualitative non-doctrinal approach, inspired by the mapping and criticism analysis of Roberto Mangabeira Unger and Dworkin s interpretivism all within the greater context of critical legal theory. This allows the research to make a detailed exploration of current structures and unearth its ideological underpinnings. The research starts by pinpointing the importance of corporate governance in the context of development theory, and it dissects its ideologically charged significance within an economicist view of the world. Then, corporations are analyzed from both historical and ontological perspectives in preparation for an alternative corporate legal theory. Such a jurisprudential approach takes, first, a descriptive form, though it then evolved into a normative one, gravitating around the goal of corporate law and the contrast between the theory of the firm and political philosophy. The tenets of law & economics are then critically dissected. The main findings are that law & economics appeal arises from its sound epistemological construction. It takes off from an ethical position (i.e. utilitarianism) which then serves a methodological path (i.e. positivist empiricism), on top of which a theoretical framework is developed (i.e. neoclassical economics). Its weakness, though, consists of simplistic and erroneous elemental assumptions. Based on these findings, the research proposes an alternative to the law & economics theory of corporate governance built on top of a model which mirrors its sound epistemological construction, though centers around a normative jurisprudence analysis of individual and corporate personhood and to the core of corporations, what they really are, and what they should be used for.
  • Tuittila, Eeva-Stiina (Helsingin yliopisto, 2000)
  • Loponen, Heidi (Helsingin yliopisto, 2012)
    Sensory hair cells and supporting cells of the mammalian inner ear are non-dividing cells, in contrast to supporting cells of non-mammalian species that have a natural capacity for cell cycle re-entry and production of new hair cells following traumas. The mechanisms regulating the maintenance of the postmitotic state of hair cells and supporting cells are not fully understood. In this thesis, the focus has been on understanding the involvement of the core cell cycle machinery in the regulation of the postmitotic state in the inner ear sensory epithelia. Cyclin dependent kinase inhibitors (CKIs) are negative cell cycle regulators that inhibit the progression of cell cycle. In several tissues they have an important role in regulating the postmitotic state of quiescent cells. We showed that two CKIs, p19Ink4d and p21Cip1, act in co-operation to maintain the postmitotic state of hair cells. When p19Ink4d and p21Cip1 were simultaneously inactivated in mouse, auditory hair cells re-entered the cell cycle during a restricted period in early postnatal life. Furthermore, part of the hair cells that had re-entered the cell cycle also progressed to mitosis. However, cell cycle re-activation led rapidly to the activation of DNA damage response pathway and finally to p53-mediated apoptosis. These results demonstrated that postnatal hair cells do not tolerate forced cell cycle re-entry. We also analyzed the expression of other cell cycle regulators in the inner ear and found that cyclin D1 (cD1) is expressed transiently in postnatal auditory hair cells. This transient expression pattern corresponded temporarily and spatially to the abnormal proliferation pattern seen in the p19Ink4d/p21Cip1 mutant mice. This suggested that both CKIs and cD1 are involved in the control of the postmitotic state of hair cells. We tested this hypothesis by ectopically expressing cD1 in vestibular hair cells where it is not normally expressed. Only vestibular hair cells from p19Ink4d/p21Cip1 mutant mice, but not from wild type mice re-entered the cell cycle in response to ectopic cD1 expression, confirming our hypothesis. These results emphasized that the control of the postmitotic state is a complex interplay between negative and positive cell cycle regulators. Neonatal vestibular supporting cells are able to respond to mitogenic stimuli and re-enter the cell cycle. However, this response is rapidly lost during postnatal life. We found that cD1 is strongly expressed in neonatal vestibular supporting cells during the time period when these cells are able to re-enter the cell cycle in response to mitogens. This correlation suggested that the inability of mature supporting cells to re-enter the cell cycle could be caused by the absence of cD1 in these cells. We expressed cD1 ectopically in mature vestibular supporting cell in tissue culture and showed that ectopic cD1 expression triggered robust cell cycle re-entry. However, only a small fraction of supporting cells progressed to mitosis. The majority of cell cycle reactivated supporting cells showed DNA damage and arrested at the G2/M boundary. This thesis work shows that differentiated hair cells and supporting cells can be forced to re-enter the cell cycle. However, there are severe restrictions in their proliferative potential.