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  • Rytkönen, Anna (Helsingin yliopisto, 2011)
    Human-mediated movement of plants and plant products is now generally accepted to be the primary mode of introduction of plant pathogens. Species of the genus Phytophthora are commonly spread in this way and have caused severe epidemics in silviculture, horticulture as well as natural systems all over the world. The aims of the study were to gather information on the occurrence of Phytophthora spp. in Finnish nurseries, to produce information for risk assessments for these Phytophthora spp. by determining their host ranges and tolerance of cold temperatures, and to establish molecular means for their detection. Phytophthora cactorum was found to persist in natural waterbodies and results suggest that irrigation water might be a source of inoculum in nurseries. In addition to P. cactorum, isolates from ornamental nursery Rhododendron yielded three species new to Finland: P. ramorum, P. plurivora and P. pini. The only species with quarantine status, P. ramorum, was most adapted to growth in cold temperatures and able to persist in the nursery in spite of an annual sanitation protocol. Phytophthora plurivora and the closely related P. pini had more hosts among Nordic tree and plant species than P. ramorum and P. cactorum, and also had higher infectivity rates. All four species survived two weeks in -5 °C , and thus soil survival of these Phytophthoras in Finland is likely under current climatic conditions. The most common tree species in Finnish nurseries, Picea abies, was highly susceptible to P. plurivora and P. pini in pathogenicity trials. In a histological examination of P. plurivora in P. abies shoot tissues, fast necrotrophic growth was observed in nearly all tissues. The production of propagules in P. abies shoot tissue was only weakly indicated. In this study, a PCR DGGE technique was developed for simultaneous detection and identification of Phytophthora spp. It reliably detected Phytophthora in plant tissues and could discriminate most test species as well as indicate instances of multiple-species infections. It proved to be a useful detection and identification tool either applied alone or in concert with traditional isolation culture techniques. All of the introduced species of Phytophthora had properties that promote a high risk of establishment and spread in Finland. It is probable that more pathogens of this genus will be introduced and become established in Finland and other Nordic countries unless efficient phytosanitary control becomes standard practice in the international plant trade.
  • Forsström, Laura Johanna (Helsingin yliopisto, 2006)
    Climate is warming and it is especially seen in arctic areas, where the warming trend is expected to be greatest. Arctic freshwater ecosystems, which are a very characteristic feature of the arctic landscape, are especially sensitive to climate change. They could be used as early warning systems, but more information about the ecosystem functioning and responses are needed for proper interpretation of the observations. Phytoplankton species and assemblages could be especially suitable for climate-related studies, since they have short generation times and react rapidly to changes in the environment. In addition, phytoplankton provides a good tool for lake classifications, since different species have different requirements and tolerance ranges for various environmental factors. The use of biological indicators is especially useful in arctic areas, were many of the chemical factors commonly fall under the detection limit and therefore do not provide much information about the environment. This work brings new information about species distribution and dynamics of arctic freshwater phytoplankton in relation to environmental factors. The phytoplankton of lakes in Finnish Lapland and other European high-altitude or high-latitude areas were compared. Most lakes were oligotrophic and dominated by flagellated species belonging to chrysophytes, cryptophytes and dinoflagellates. In Finnish Lapland cryptophytes were of less importance, whereas desmids had high species richness in many of the lakes. In Pan-European scale, geographical and catchment-related factors were explaining most of the differences in species distributions between different districts, whereas lake water chemistry (especially conductivity, SiO2 and pH) was most important regionally. Seasonal and interannual variation of phytoplankton was studied in subarctic Lake Saanajärvi. Characteristic phytoplankton species in this oligotrophic, dimictic lake belonged mainly to chrysophytes and diatoms. The maximum phytoplankton biomass in Lake Saanajärvi occurs during autumn, while spring biomass is very low. During years with heavy snow cover the lake suffers from pH drop caused by melt waters, but the effects of this acid pulse are restricted to surface layers and last for a relatively short period. In addition to some chemical parameters (mainly Ca and nutrients), length of the mixing cycle and physical factors such as lake water temperature and thermal stability of water column had major impact on phytoplankton dynamics. During a year with long and strong thermal stability, the phytoplankton community developed towards an equilibrium state, with heavy dominance of only a few taxa for a longer period of time. During a year with higher windiness and less thermal stability, the species composition was more diverse and species with different functional strategies were able to occur simultaneously. The results of this work indicate that although arctic lakes in general share many common features concerning their catchment and water chemistry, large differences in biological features can be found even in a relatively small area. Most likely the lakes with very different algal flora do not respond in a similar way to differences in the environmental factors, and more information about specific arctic lake types is needed. The results also show considerable year to year differences in phytoplankton species distribution and dynamics, and these changes are most likely linked to climatic factors.
  • Peltomaa, Elina (Helsingin yliopisto, 2013)
    Phytoplankton constitute the autotrophic, photosynthesizing component of the plankton community in freshwaters as well as in oceans. Today, phytoplankton account for about half of Earth s primary production (PP). Carbon and energy fixed by phytoplankton are transported further in the aquatic food web to heterotrophic zooplankton and finally to fish or, alternatively, are decomposed by heterotrophic bacteria that also act as food for higher trophic-level organisms. Since phytoplankton fix inorganic carbon (IC), they are highly important in lake carbon cycling and balance. Many of the lakes in the boreal area are characterized by heavy loadings of brown-coloured humic matter, mostly dissolved organic carbon (DOC), that diminishes light penetration in the water column. This is problematic for phytoplankton which, as photosynthetic organisms, are dependent on solar radiation. The phytoplanktonic life in boreal humic lakes is also hampered by strong thermal stratification patterns that due to nutrient uptake, lead to inorganic nutrient limitation in the illuminated epilimnion. However, nutrients are often plentiful in the dark hypolimnion. Since phytoplankton are ubiquitous in aquatic ecosystems, they must have several adaptations to help them survive in various environments, including boreal humic lakes. The present study focused on the traits of motility and cell size, both of which affect phytoplankton capability to not only obtain nutrients and light, but also to avoid zooplankton grazing. Special attention was given to the group of autotrophic picoplankton (APP), which are nonmotile, small (cell size 0.2 2 µm) and less studied than the larger phytoplankton. The seasonal dynamics of APP and larger phytoplankton were associated with changes in the abiotic environment, especially parameters prone to the ongoing climate change. In addition, the associations between phytoplankton and their competitors and grazers in the microbial food web (MFW), as well as the possible top-down effects of fish on the MFW, phytoplankton and surface water carbon dioxide (CO2) concentrations were studied in more detail. Four of the five studies were undertaken in situ in the small, strongly stratified, humic headwater Lake Valkea-Kotinen. The fifth study was a fish biomanipulation experiment conducted in enclosures in the humic Lake Pääjärvi and the clearwater Lake Vesijärvi. The most successful phytoplankton taxa in Lake Valkea-Kotinen in terms of PP as well as biomass were flagellated. However, motility was really advantageous only when combined with large cell size (> 20 µm): Peridinium dinoflagellates dominated in PP and the biomass in spring and autumn, whereas in summer Gonyostomum semen (Ehr.) Diesing took over. This was probably because only the large cells were able to migrate long distances between the illuminated epilimnion and nutrient-rich hypolimnion. Interestingly, the most abundant phytoplankton taxa in Lake Valkea-Kotinen were the nonmotile and tiny (~ 2 µm) Choricystis (Skuja) Fott-like eukaryotic APP. The strength of the APP was in isopycny, i.e. the capability to remain at the boundary layer between the epi- and hypolimnion, where they obtained access to light and nutrients. Both G. semen and APP correlated positively with high water column stability, which also indicates that they benefitted from strong stratification patterns. There were changes in the water quality in Lake Valkea-Kotinen during the study period of 1990 2006, most importantly, as increases in DOC and water colour, whereas phosphorus, which was the limiting nutrient, decreased. This was problematic for the large flagellates (studied in 1990 2003) and prokaryotic APP (Merismopedia warmingiana Lagerheim; in 2002 2006). However, the eukaryotic APP (in 2002 2006) were favoured by the increased water colour. APP abundance correlated negatively with heterotrophic bacteria in the epilimnion of Lake Valkea-Kotinen, which indicates nutrient competition between these two groups. The bacteria correlated positively with large phytoplankton (measured as chlorophyll a), and probably were partly sustained by G. semen, which was associated with high extracellular organic carbon (EOC) release. However, both the APP and bacterial numbers were in general low in Lake Valkea-Kotinen, which was explained by the high nanoflagellate (NF) and ciliate abundance. Nevertheless, the NFs did not graze on the APP, and the APP as well as the larger phytoplankton were able to avoid ciliate grazing during the strongest stagnation by remaining in the anoxic parts of the water column, where algivorous ciliates were less abundant. The enclosure experiment in lakes Pääjärvi and Vesijärvi showed no top-down effects of fish on APP or any other components of the MFW. This was probably due to the low abundance of cladocerans, especially the large daphnids. However, in the humic Lake Pääjärvi, fish influenced the food web via nutrient enrichment, i.e. through bottom-up effects. The total phytoplankton biomass did not change, but the PP increased and led to increments in bacterial production (BP) and ciliates, which took advantage of the enhanced phytoplankton production. Therefore, although unexpected, the higher PP did not translate into lower water CO2 concentration, but the BP and ciliate algivory increased concurrently and produced more CO2. Thus, the net ecosystem production (NEP) remained stable.
  • Kauppila, Pirkko (Helsingin yliopisto, 2007)
    The tackling of coastal eutrophication requires water protection measures based on status assessments of water quality. The main purpose of this thesis was to evaluate whether it is possible both scientifically and within the terms of the European Union Water Framework Directive (WFD) to assess the status of coastal marine waters reliably by using phytoplankton biomass (ww) and chlorophyll a (Chl) as indicators of eutrophication in Finnish coastal waters. Empirical approaches were used to study whether the criteria, established for determining an indicator, are fulfilled. The first criterion (i) was that an indicator should respond to anthropogenic stresses in a predictable manner and has low variability in its response. Summertime Chl could be predicted accurately by nutrient concentrations, but not from the external annual loads alone, because of the rapid affect of primary production and sedimentation close to the loading sources in summer. The most accurate predictions were achieved in the Archipelago Sea, where total phosphorus (TP) and total nitrogen (TN) alone accounted for 87% and 78% of the variation in Chl, respectively. In river estuaries, the TP mass-balance regression model predicted Chl most accurately when nutrients originated from point-sources, whereas land-use regression models were most accurate in cases when nutrients originated mainly from diffuse sources. The inclusion of morphometry (e.g. mean depth) into nutrient models improved accuracy of the predictions. The second criterion (ii) was associated with the WFD. It requires that an indicator should have type-specific reference conditions, which are defined as "conditions where the values of the biological quality elements are at high ecological status". In establishing reference conditions, the empirical approach could only be used in the outer coastal water types, where historical observations of Secchi depth of the early 1900s are available. The most accurate prediction was achieved in the Quark. In the inner coastal water types, reference Chl, estimated from present monitoring data, are imprecise - not only because of the less accurate estimation method but also because the intrinsic characteristics, described for instance by morphometry, vary considerably inside these extensive inner coastal types. As for phytoplankton biomass, the reference values were less accurate than in the case of Chl, because it was possible to estimate reference conditions for biomass only by using the reconstructed Chl values, not the historical Secchi observations. An paleoecological approach was also applied to estimate annual average reference conditions for Chl. In Laajalahti, an urban embayment off Helsinki, strongly loaded by municipal waste waters in the 1960s and 1970s, reference conditions prevailed in the mid- and late 1800s. The recovery of the bay from pollution has been delayed as a consequence of benthic release of nutrients. Laajalahti will probably not achieve the good quality objectives of the WFD on time.    The third criterion (iii) was associated with coastal management including the resources it has available. Analyses of Chl are cheap and fast to carry out compared to the analyses of phytoplankton biomass and species composition; the fact which has an effect on number of samples to be taken and thereby on the reliability of assessments. However, analyses on phytoplankton biomass and species composition provide more metrics for ecological classification, the metrics which reveal various aspects of eutrophication contrary to what Chl alone does.
  • Juuti, Sini (Helsingin yliopisto, 2012)
    The study as a whole examined piano musicians identity negotiations in the context of their music studies and their transition to working life. This research report and the articles accompanying it also introduce a socio-culturally oriented approach to the study of musical identities. Study I explored adult instrumental students identity work while negotiating entry to a prestigious music academy. The specific focus was on how students accounts of their competencies vis-à-vis their peers are implicated in their musical identity work, and how students accounts of their own and others participation in and engagement with the musical practices of the academy resourced their musical identity work. A further concern was how students accounts of life-courses and trajectories were implicated in their musical identity work. Study II focused on how solo piano students identity projects were mediated within the student-teacher relationship. It examined how solo piano students identity projects were mediated within and in relation to their interpretative work on the canon, undertaken along with their teacher, and further, how their identity as a solo piano student was negotiated in relation to other ongoing musical identity projects. Study III focused on career-young professional pianists talk about the transition from study within a music academy to working life. The focus was especially on the ways in which they characterised the nature and significance of this transition, from very traditional practice, and how they (re-)negotiated their professional identities as working musicians and pianists in their contemporary working lives. The participants of the overall study were ten solo piano students who were interviewed once during their studies at the Sibelius Academy. Four of these original participants were followed up for about eight years from the original interviews when entering professional working life. The starting point for the methods used in the study was the socio-cultural framework plus qualitative thematic analysis. Within this study, identity negotiations and the relation between individual and social aspects of identity were researched through the collection of the musicians accounts of their musical histories and experiences situated in the daily practices of their study and work. The analytical method involved the initial identification of key themes, with the detailed analysis then focusing on the particular ways in which the participants talked about the process of becoming musicians. The results showed how identity work is a complex, mediated process. The comparative dynamics amongst peers were seen as a key mediator of the identity work done during studies at the academy. Furthermore, student-teacher interactions emerged as crucial sites for identity negotiations. It seemed that a collegial and collaborative approach to the interpretation of music, and the associated understanding that came with it, fostered professional growth and enhanced artistic confidence. This work also highlighted the conflicts and problematic identity positions that emerge in the creative relationship between the teacher and the student a relationship in which visions and insights are not necessarily shared. The analyses also exemplify how in some circumstances the envisaged reactions of the teacher and the associated risk of troubled identity positions problematised students engagement with popular forms of music-making. Furthermore, it was observed that the creation of novel interpretations of pieces from the canon form a central aspect of one s personal musical identity and is a socially and culturally situated act. The results of this study also highlighted how, especially during the students transition to the music community, they seemed unable to define community-level norms and expectations. Moreover, they talked against some of these. Talking against emerged as strongly agentic identity work. Thereafter, in the context of the transition from music studies to working life, there was clear evidence of the emergence of the informants own stories , own ways and the use of inner resources. Agency was thus clearly observable in the career-young professional musicians construction and re-construction of their own creative practices and paths. These paths were not fixed or dependent on communal expectations; rather, they reflected freedom, widening perspectives and independence, the embracing of multiple influences, and the anchor- ing of individual lives in more holistic ways. One of the key elements in the process of becoming agentic seemed to be the acceptance of multiplicity.
  • Navickaitė-Martinelli, Lina (Helsingin yliopisto, 2014)
    In an attempt to expand and enrich the existing trends of musical performance studies, as well as exploit the potentials of semiotic analysis, this dissertation offers the theoretical perspective that enables the unfolding of the multiple meanings generated by and communicated through the performer s art. Without denying that musical performance is inevitably associated with the opus, the semiotic approach, it is proposed here, should study performance as encompassing all the exogenic meanings that do not necessarily depend on a musical work. Thus, the focus of the present dissertation is the figure of a classical music performer as a significant part of society, as well as cultural, institutional and personal discourses that both generate the art of music performance and originate from it. The main targets here are mapping the predominant tendencies of the art of musical performance during the twentieth century and proposing a form of semiotic analysis of different representations and self-representations that musical performers, pianists in particular, put into action in their interactions with social and cultural contexts (including different types of performer-listener communication processes, scholarly analyses, the various media through which the art of music performance is disseminated, and aspects related to the marketing and ideologizing of today s performance practices). The dissertation is structured into four parts. Part 1 introduces a semiotic framework for studying musical performance. Part 2 discusses a variety of meanings communicated through the performers art as well as the media in which the art of classical piano music performance is operating. Part 3 positions the performers art within the Western musical canon by examining Beethoven interpretations as played by pianists of various cultural and historical backgrounds. The concluding Part 4 presents novel discourses on the art of musical performance by analyzing 11 personal websites of Lithuanian classical pianists as an important vehicle of contemporary performers for communicating their artistic identities. It is claimed in this dissertation that the combination of semiotic and musicological approaches is relevant and revealing in the study of musical performance art in that it strongly make a case for current musicology to elaborate increasingly interdisciplinary paradigms and modes of investigation.
  • Vuolasto, Johanna (Helsingin yliopisto, 2011)
    The image of Pietism a window to personal spirituality. The teachings of Johann Arndt as the basis of Pietist emblems The Pietist effect on spiritual images has to be scrutinised as a continuum initiating from the teachings of Johann Arndt who created a protestant iconography that defended the status of pictures and images as the foundation of divine revelation. Pietist artworks reveal Arndtian part of secret, eternal world, and God. Even though modern scholars do not regarded him as a founding father of Pietism anymore, his works have been essential for the development of iconography, and the themes of the Pietist images are linked with his works. For Arndt, the starting point is in the affecting love for Christ who suffered for the humankind. The reading experience is personal and the words point directly at the reader and thus appear as evidence of the guilt of the reader as well as of the love of God. Arndt uses bounteous and descriptive language which has partially affected promoting and picturing of many themes. Like Arndt, Philipp Jakob Spener also emphasised the heart that believes. The Pietist movement was born to oppose detached faith and the lack of the Holy Ghost. Christians touched by the teachings of Arndt and Spener began to create images out of metaphors presented by Arndt. As those people were part of the intelligentsia, it was natural that the fashionable emblematics of the 17th century was moulded for the personal needs. For Arndt, the human heart is manifested as a symbol of soul, personal faith or unbelief as well as an allegory of the burning love for Jesus. Due to this fact, heart emblems were gradually widely used and linked with the love of Christ. In the Nordic countries, the introduction of emblems emanated from the gentry s connections to the Central Europe where emblems were exploited in order to decorate books, artefacts, interiors, and buildings as well as visual/literal trademarks of the intelligentsia. Emblematic paintings in the churches of the castles of Venngarn (1665) and Läckö (1668), owned by Magnus Gabriel De la Gardie, are one of the most central interior paintings preserved in the Nordic countries, and they emphasise personal righteous life. Nonetheless, it was the books by Arndt and the Poet s Society in Nurnberg that bound the Swedish gentry and the scholars of the Pietist movement together. The Finnish gentry had no castles or castle churches so they supported county churches, both in building and in maintenance. As the churches were not private, their iconography could not be private either. Instead, people used Pietist symbols such as Agnus Dei, Cor ardens, an open book, beams, king David, frankincense, wood themes and Virtues. In the Pietist images made for public spaces, the attention is focused on pedagogical, metaphorical, and meaningful presentation as well as concealed statements.
  • Rahkala, Mari-Johanna (Helsingin yliopisto, 2010)
    The aim of this research is to present, interpret and analyze the phenomenon of pilgrimage in a contemporary, suburban Greek nunnery, and to elucidate the different functions that the present-day convent has for its pilgrims. The scope of the study is limited to a case nunnery, the convent of the Dormition of the Virgin, which is situated in Northern Greece. The main corpus of data utilized for this work consists of 25 interviews and field diary material, which was collected in the convent mainly during the academic year 2002-2003 and summer 2005 by means of participant observation and unstructured thematic interviewing. It must be noted that most Greek nunneries are not really communities of hermits but institutions that operate in complex interaction with the surrounding society. Thus, the main interest in this study is in the interaction between pilgrims and nuns. Pilgrimage is seen here as a significant and concrete form of interaction, which in fact makes the contemporary nunneries dynamic scenes of religious, social and sometimes even political life. The focus of the analysis is on the pilgrims’ experiences, reflected upon on the levels of the individual, the Church institution, and society in general. This study shows that pilgrimage in a suburban nunnery, such as the convent of the Dormition, can be seen as part of everyday religiosity. Many pilgrims visit the convent regularly and the visitation is a lifestyle the pilgrims have chosen and wish to maintain. Pilgrimage to a contemporary Greek nunnery should not be ennobled, but seen as part of a popular religious sentiment. The visits offer pilgrims various tools for reflecting on their personal life situations and on questions of identity. For them the full round of liturgical worship is a very good reason for going to the convent, and many see it as a way of maintaining their faith and of feeling close to God. Despite cultural developments such as secularization and globalization, pilgrims are quite loyal to the convent they visit. It represents the positive values of ‘Greekness’ and therefore they also trust the nuns’ approach to various matters, both personal and political. The coalition of Orthodoxy and nationalism is also visible in their attitudes towards the convent, which they see as a guardian of Hellenism and as nurturing Greek values both now and in the future.
  • Huuskonen, Kari (Helsingin yliopisto, 2013)
    From The Dark Side: Experiences On Modernisation In The Narrative Community Of Visually Impaired People My study describes the experiences on modernisation among the first generations of the organised visually impaired people in the narrative context of the end of the 19:th century and the first decades of the 20:th century. My research material includes oral and written descriptions, photographs, and various objects that describe the thoughts and experiences of people in the past. The oldest data I found has been developed simultaneously with the formation of the publicity institution in Finland. This data includes both my main source the magazines of blind people and the minutes of blind people s associations. They have been supplemented by biographical interviews. The eldest interviewees have been among the founders of blind people s own magazines and associations in the beginning of the 20:th century. It has been an essential goal of my study to bring these thoughts and experiences of the past into the current discussion going on in the academic disability research: which/what kind of social changes connected with modernisation have increased the exclusion of disabled citizens from society, and which have promoted their integration. In the 19:th century, an institutional philosophy was adopted from other European countries to the Finnish education of disabled children. According to my study, this did not exclude the visually impaired from society. Most of the narrators included in the study lost the daily contact into their close communities when they started at the schools for the blind. Yet because of the huge effort that the society forced them to make, most of them developed into independent and self-supporting citizens. The study also shows that the schools of the blind were not closed institutional communities. Institutions for the blind were meeting points of several generations as well as of different thoughts and philosophies. For a long time, they functioned as the main arenas for the organisational life and social action of the visually impaired, where the community-based culture of activity gradually developed from the satisfaction of basic needs into social forms and a common strategy of survival.
  • Spoof, Marja (Helsingin yliopisto, 2007)
    The purpose of this study is to determine what class teachers and special teachers emphasise in ethical consideration, in which situations they find that ethical difficulties arise and how they would overcome them. In additions, the study aims to describe the effects of ethical con-sideration on the teachers` work. The theoretical backround is based on theories concerning the ethics of the teacher and the literature associated with education and teaching. The empirical study was based on data obtained through questionnaires and interviews. The questionnaires were posted to 470 randomly-selected class teachers and special teachers; 298 of them (63%) completed and returned the questionnaire, and 19 teachers were inter-viewed. The results of the questionnaires and the interviews were examined crosswise with a mixed-methods procedure. The questionnaires were analysed by factor analysis. Those items which rose above the av-erage served as the foundation for the analysis. The questionnaires also included open ques-tions. These questions and the interviews were analysed with a content analysis method. Some principles of this method were combined with the results of the questionnaires to in-crease mutual understanding. In this study, the ethical consideration of the teachers was divided in to four notable parts: 1) moral obligations, 2) respect for the teaching stuff, 3) the demand for responsibility, and 4) dependence on the situation. These items were also notable both in situations that were ethi-cally difficult for teachers and in their solutions to these situations. It became evident that these situations were very common in everyday work and resulted from the character of the teachers´ work. This study showed that the teacher meets the pupils as a group and that the teacher must examine according to the circumstances the truth, individuality, special ar-rangements and co-operation between the school and the parents. The teachers` continuous lack of time limited the ethical consideration. It emerged that the teachers consider their work very multi-faceted and that the sense of obligation, power and responsibility was inevitably received emphasis. The consciousness of authority and the responsibilities associated with it seemed, however, to strengthen this ac-tion. The study showed that the teachers, especially the young female ones, long for more solidarity. Significantly, such experience does not eliminate the importance of ethical consid-eration; on the contrary, it deepens it. According to the results, creating conditions and cir-cumstances for the teachers that open co-operation is inevitable, and easy interaction will in-evitably be possible in the future. There was not observed any differences in ethical consideration between class teachers and special teachers. Therefore, the integration of the pupils to general teaching cannot be consid-ered questionable. Teachers´ answers suggested that ethical consideration improved the tolerance of stress, increased self-confidence and courage as well as belief in the future. The teachers considered ethical consideration important and encouraging for it increased justice and empathy in the teachers´ work.
  • Novitski, Nikolai (Helsingin yliopisto, 2006)
    Pitch discrimination is a fundamental property of the human auditory system. Our understanding of pitch-discrimination mechanisms is important from both theoretical and clinical perspectives. The discrimination of spectrally complex sounds is crucial in the processing of music and speech. Current methods of cognitive neuroscience can track the brain processes underlying sound processing either with precise temporal (EEG and MEG) or spatial resolution (PET and fMRI). A combination of different techniques is therefore required in contemporary auditory research. One of the problems in comparing the EEG/MEG and fMRI methods, however, is the fMRI acoustic noise. In the present thesis, EEG and MEG in combination with behavioral techniques were used, first, to define the ERP correlates of automatic pitch discrimination across a wide frequency range in adults and neonates and, second, they were used to determine the effect of recorded acoustic fMRI noise on those adult ERP and ERF correlates during passive and active pitch discrimination. Pure tones and complex 3-harmonic sounds served as stimuli in the oddball and matching-to-sample paradigms. The results suggest that pitch discrimination in adults, as reflected by MMN latency, is most accurate in the 1000-2000 Hz frequency range, and that pitch discrimination is facilitated further by adding harmonics to the fundamental frequency. Newborn infants are able to discriminate a 20% frequency change in the 250-4000 Hz frequency range, whereas the discrimination of a 5% frequency change was unconfirmed. Furthermore, the effect of the fMRI gradient noise on the automatic processing of pitch change was more prominent for tones with frequencies exceeding 500 Hz, overlapping with the spectral maximum of the noise. When the fundamental frequency of the tones was lower than the spectral maximum of the noise, fMRI noise had no effect on MMN and P3a, whereas the noise delayed and suppressed N1 and exogenous N2. Noise also suppressed the N1 amplitude in a matching-to-sample working memory task. However, the task-related difference observed in the N1 component, suggesting a functional dissociation between the processing of spatial and non-spatial auditory information, was partially preserved in the noise condition. Noise hampered feature coding mechanisms more than it hampered the mechanisms of change detection, involuntary attention, and the segregation of the spatial and non-spatial domains of working-memory. The data presented in the thesis can be used to develop clinical ERP-based frequency-discrimination protocols and combined EEG and fMRI experimental paradigms.
  • Torppa, Ritva (Helsingin yliopisto, 2015)
    The cochlear implant (CI) provides a sensation of hearing for deaf-born children. However, many CI children show poor language outcomes, which may be related to the deficiency of CIs in delivering pitch. This thesis studies the development of those neural processes and behavioural skills linked to the perception of pitch which may play a role in language acquisition. We measured with event-related brain potentials (ERPs) the neural discrimination of and attention shift to changes in music, the perception of word and sentence stress and related acoustic cues, and the auditory working memory (forward digit span) in 4̶ 13-year-old normally hearing (NH) and early-implanted children. We studied how the development of these aspects is related to musical activities known to advance brain development and perceptual skills in the NH population, and whether the perception of music is connected to word stress or visuospatial perception in NH adults. With regard to the development of neural responses, we found for the CI children usually well-formed ERP waveforms resembling those found for the NH children. However, some brain responses implied impoverished processing for the CI children, especially for timbre and pitch. The CI children who sang regularly at home were advantaged over the other CI children for the development of attention shift, which was linked to improved auditory working memory, implying better neural discrimination, an advantaged development of neural networks for attention and better updating of auditory working memory for the CI singers. For the CI children perception of word and sentence stress improved with improving discrimination of pitch (f0) and intensity and auditory working memory. Only the CI children participating in supervised musical activities performed and developed similarly to the NH children in these skills. The perception of musical rhythm improved with improving word stress and visuospatial perception for the NH adults. The results indicate that (i) perception of music and speech are connected not only via pitch and timbre, but also via rhythm, and (ii) the combination of singing at home and taking part in supervised musical activities, using also rhythmic exercises and visual cues, might be the best way to optimize pitch-related abilities, underlying cognitive functions, spoken language skills and quality of life for early-implanted children.
  • Raivio, Minna (Helsingin yliopisto, 2007)
    Pitfalls in the treatment of persons with dementia Persons with dementia require high-quality health care, rehabilitation and sufficient social services to support their autonomy and to postpone permanent institutionalization. This study sought to investigate possible pitfalls in the care of patients with dementia: hip fracture rehabilitation, use of inappropriate or antipsychotic medication, social and medicolegal services offered to dementia caregiving families. Three different Finnish samples were used from years 1999-2005, mean age 78 to 86 years. After hip fracture operation, the weight-bearing restriction especially in group of patients with dementia, was associated with a longer rehabilitation period (73.5 days vs. 45.5 days, p=0.03) and the inability to learn to walk after six weeks (p<0.001). Almost half (44%) of the pre-surgery home-dwellers with dementia in our sample required permanent hospitalization after hip fracture. Potentially inappropriate medication was used among 36.2% of nursing home and hospital patients. The most common PIDs in Finland were temazepam over 15 mg/day, oxybutynin, and dipyridamole. However, PID use failed to predict mortality or the use of health services. Nearly half (48.4%) of the nursing home and hospital patients with dementia used antipsychotic medication. The two-year mortality did not differ among the users of conventional or atypical antipsychotics or the non-users (45.3% vs.32.1% vs.49.6%, p=0.195). The mean number of hospital admissions was highest among non-users (p=0.029). A high number of medications (HR 1.12, p<0.001) and the use of physical restraints (HR 1.72, p=0.034) predicted higher mortality at two years, while the use of atypical antipsychotics (HR 0.49, p=0.047) showed a protective effect, if any. The services most often offered to caregiving families of persons with Alzheimer s disease (AD) included financial support from the community (36%), technical devices (33%), physiotherapy (32%), and respite care in nursing homes (31%). Those services most often needed included physiotherapy for the spouse with dementia (56%), financial support (50%), house cleaning (41%), and home respite (40%). Only a third of the caregivers were satisfied with these services, and 69% felt unable to influence the range of services offered. The use of legal guardians was quite rare (only 4.3%), while the use of financial powers of attorney was 37.8%. Almost half (47.9%) of the couples expressed an unmet need for discussion with their doctor about medico-legal issues, while only 9.9% stated that their doctor had informed them of such matters. Although we already have many practical methods to develop the medical and social care of persons with AD, these patients and their families require better planning and tailoring of such services. In this way, society could offer these elderly persons better quality of life while economizing on its financial resources. This study was supported by Social Insurance Institution of Finland and part of it made in cooperation with the The Central Union of the Welfare for the Aged, Finland.
  • Tikkanen, Minna (Helsingin yliopisto, 2008)
    Placental abruption, one of the most significant causes of perinatal mortality and maternal morbidity, occurs in 0.5-1% of pregnancies. Its etiology is unknown, but defective trophoblastic invasion of the spiral arteries and consequent poor vascularization may play a role. The aim of this study was to define the prepregnancy risk factors of placental abruption, to define the risk factors during the index pregnancy, and to describe the clinical presentation of placental abruption. We also wanted to find a biochemical marker for predicting placental abruption early in pregnancy. Among women delivering at the University Hospital of Helsinki in 1997-2001 (n=46,742), 198 women with placental abruption and 396 control women were identified. The overall incidence of placental abruption was 0.42%. The prepregnancy risk factors were smoking (OR 1.7; 95% CI 1.1, 2.7), uterine malformation (OR 8.1; 1.7, 40), previous cesarean section (OR 1.7; 1.1, 2.8), and history of placental abruption (OR 4.5; 1.1, 18). The risk factors during the index pregnancy were maternal (adjusted OR 1.8; 95% CI 1.1, 2.9) and paternal smoking (2.2; 1.3, 3.6), use of alcohol (2.2; 1.1, 4.4), placenta previa (5.7; 1.4, 23.1), preeclampsia (2.7; 1.3, 5.6) and chorioamnionitis (3.3; 1.0, 10.0). Vaginal bleeding (70%), abdominal pain (51%), bloody amniotic fluid (50%) and fetal heart rate abnormalities (69%) were the most common clinical manifestations of placental abruption. Retroplacental blood clot was seen by ultrasound in 15% of the cases. Neither bleeding nor pain was present in 19% of the cases. Overall, 59% went into preterm labor (OR 12.9; 95% CI 8.3, 19.8), and 91% were delivered by cesarean section (34.7; 20.0, 60.1). Of the newborns, 25% were growth restricted. The perinatal mortality rate was 9.2% (OR 10.1; 95% CI 3.4, 30.1). We then tested selected biochemical markers for prediction of placental abruption. The median of the maternal serum alpha-fetoprotein (MSAFP) multiples of median (MoM) (1.21) was significantly higher in the abruption group (n=57) than in the control group (n=108) (1.07) (p=0.004) at 15-16 gestational weeks. In multivariate analysis, elevated MSAFP remained as an independent risk factor for placental abruption, adjusting for parity ≥ 3, smoking, previous placental abruption, preeclampsia, bleeding in II or III trimester, and placenta previa. MSAFP ≥ 1.5 MoM had a sensitivity of 29% and a false positive rate of 10%. The levels of the maternal serum free beta human chorionic gonadotrophin MoM did not differ between the cases and the controls. None of the angiogenic factors (soluble endoglin, soluble fms-like tyrosine kinase 1, or placental growth factor) showed any difference between the cases (n=42) and the controls (n=50) in the second trimester. The levels of C-reactive protein (CRP) showed no difference between the cases (n=181) and the controls (n=261) (median 2.35 mg/l [interquartile range {IQR} 1.09-5.93] versus 2.28 mg/l [IQR 0.92-5.01], not significant) when tested in the first trimester (mean 10.4 gestational weeks). Chlamydia pneumoniae specific immunoglobulin G (IgG) and immunoglobulin A (IgA) as well as C. trachomatis specific IgG, IgA and chlamydial heat-shock protein 60 antibody rates were similar between the groups. In conclusion, although univariate analysis identified many prepregnancy risk factors for placental abruption, only smoking, uterine malformation, previous cesarean section and history of placental abruption remained significant by multivariate analysis. During the index pregnancy maternal alcohol consumption and smoking and smoking by the partner turned out to be the major independent risk factors for placental abruption. Smoking by both partners multiplied the risk. The liberal use of ultrasound examination contributed little to the management of women with placental abruption. Although second-trimester MSAFP levels were higher in women with subsequent placental abruption, clinical usefulness of this test is limited due to low sensitivity and high false positive rate. Similarly, angiogenic factors in early second trimester, or CRP levels, or chlamydial antibodies in the first trimester failed to predict placental abruption.
  • Noschis, Elias (Helsingin yliopisto, 2006)
    The TOTEM experiment at the LHC will measure the total proton-proton cross-section with a precision better than 1%, elastic proton scattering over a wide range in momentum transfer -t= p^2 theta^2 up to 10 GeV^2 and diffractive dissociation, including single, double and central diffraction topologies. The total cross-section will be measured with the luminosity independent method that requires the simultaneous measurements of the total inelastic rate and the elastic proton scattering down to four-momentum transfers of a few 10^-3 GeV^2, corresponding to leading protons scattered in angles of microradians from the interaction point. This will be achieved using silicon microstrip detectors, which offer attractive properties such as good spatial resolution (<20 um), fast response (O(10ns)) to particles and radiation hardness up to 10^14 "n"/cm^2. This work reports about the development of an innovative structure at the detector edge reducing the conventional dead width of 0.5-1 mm to 50-60 um, compatible with the requirements of the experiment.
  • Virkki, Anne (Helsingin yliopisto, 2016)
    Planetary radar can be considered humankind's strongest instrument for post-discovery characterization and orbital refinement of near-Earth objects. After decades of radar observations, extensive literature describing the radar properties of various objects of the Solar System is currently available. Simultaneously, there is a shortage of work on what the observations imply about the physical properties of the planetary surfaces. The goal of my thesis is to fill part of this gap. Radar scattering as a term refers to alterations experienced by electromagnetic radiation in the backscattering direction when interacting with a target particle. In the thesis, I investigate by numerical modeling what role different physical properties of planetary surfaces, such as the electric permittivity, size of scatterers, or their number density, play in radar scattering. In addition, I discuss how radar observations can be interpreted based on modeling. Because all codes have their own limitations, it is crucial to compare results obtained with different methods. I use Multiple Sphere $T$-matrix method (MSTM) for clusters of spherical particles to understand scattering by closely-packed regolith particles. I use the discrete-dipole approximation code ADDA to comprehend single-scattering properties of inhomogeneous or irregular regolith particles in wavelength-scale. And finally, I use a ray-optics algorithm with radiative transfer, Siris, to simulate radar scattering by large irregular particles that mimic planetary bodies. The simulations for clusters of spherical particles reveal polarization enhancement at certain bands of sizes and refractive indices in the backscattering direction. The results from computations using MSTM and ADDA imply that the electric permittivity plays a strong part in terms of circular polarization. From the results of ray-optics computations for large, irregular particles, I derive a novel semi-analytic form for the radar scattering laws. And, by including diffuse scattering using wavelength-scale particles with laboratory-characterized geometries, we are able to simulate the effect of numerous physical properties of a realistic planetary surface on radar scattering. Our model using Siris is among the most quantitative models for radar scattering by planetary surfaces. The results support and improve the current understanding of the effects of the surface geometry, the electric permittivity, and the coherent-backscattering mechanism and can be used to interpret radar observations. Furthermore, I underscore that the roles of the absorption and the scatterer geometry must not be underestimated, albeit determining realistic values for the variables can be challenging.
  • Ronkainen, Tiina (Helsingin yliopisto, 2015)
    Northern peatlands form a large storage of terrestrial carbon and at the same time they provide an important palaeoecological archive to study past climate changes and associated carbon dynamics. One of the most widely used methods to study peatland histories is the plant macrofossil method. However, peat material of the early succession stages, the fens, is often highly decomposed hampering the identification of the fossil plant remains. Thus, current methods may give only a partial view on the past vegetation, and as a result the accuracy of carbon balance estimations and climate implications may remain low. A new promising method to study past plant assemblages from peat is the geochemical plant biomarker method, which has performed well in less decomposed bog peat environments. In my study I assess the applicability of the geochemical plant biomarker method to study past plant assemblages from highly decomposed fen peat. For the first time I apply a living fen plant biomarker training set to study past fen phases. To do this, I collected and analysed two sets of living key fen plants. The training sets included boreal fen, arctic fen and permafrost peat plateau plants. The biomarker analyses on fossil peat were applied in parallel with macrofossil analyses to two boreal and one arctic permafrost peat section, all known to contain highly decomposed peat. The analyses of living plants showed that the biomarker compositions did not differ between the same species collected from different bioclimatic zones, suggesting that, at least to some extent, plant biomarkers can be used universally beyond the geographical areas where the training set was collected. The plant biomarker analyses indicate that the n-alkanes, and their ratios, are the most useful compounds to separate fen plant groups: Sphagnum mosses and vascular plants. Results showed also that biomarker composition of fen plants did not differ substantially from their bog counterparts. However, results indicated that when a wider combination of plants, plant parts and peatland habitats are incorporated into the training set the data interpretation becomes more challenging. For example, the biomarker composition of Sphagnum mosses and sedge roots resembled each other despite their differences in biology. Thus, a larger set of proxies is advisable when plant groups need to be separated more accurately. In the peat sections studied here, the biomarker method performed well in less humified bog peat layers but less well in the highly decomposed fen peat layers. The macrofossil method proved to be most competitive proxy to reconstruct past vegetation assemblages and local environmental conditions through-out the peat sections. However, when macrofossil and biomarker data were interpreted in parallel, it became clear that biomarkers were also able to reflect the major changes in dominating plant groups and in moisture conditions. Accordingly, the analysis separated the most important bog microhabitats and the major regime shifts from fen to bog. I conclude, however, that in fen environments the interpretation of biomarker data can be rather challenging. As a result, it appears that the biomarker method, as applied here, performs the best as a complimentary proxy when used in conjunction with macrofossils, and that the data should be interpreted cautiously.
  • Tarmi, Sanna (Helsingin yliopisto, 2011)
    Agri-environmental schemes have so far resulted in only minor positive implications for the biodiversity of agricultural environments, in contrast to what has been expected. Land-use intensification has decreased landscape heterogeneity and the amount of semi-natural habitats. Field margins are uncultivated areas of permanent vegetation located adjacent to fields. Since the number of these habitats is high, investing in their quality may result in more diverse agricultural landscapes. Field margins can be considered as multifunctional habitats providing agronomic, environmental and wildlife services. This thesis aimed at examining the plant communities of different types of field margin habitats and the factors affecting their species diversity and composition. The importance of edaphic, spatial and management factors was studied on regional, landscape and habitat scales. Vegetation surveys were conducted on regional and landscape scales and a field experiment on cutting management was conducted on a habitat scale. In field margin plant communities, species appeared to be indicators of high or intermediate soil fertility and moist soil conditions. The plant species diversity found was rather low, compared with most species-rich agricultural habitats in Finland, such as dry meadows. Among regions, land-use history, main production line, natural species and human induced distribution, climate and edaphic factors were elements inducing differences in species composition. The lowest regional species diversity of field margins was related to intensive and long-term cereal production. Management by cutting and removal or grazing had a positive effect on plant species diversity. The positive effect of cutting and removal on species richness was also dependent on the adjacent source of colonizing species. Therefore, in species-poor habitats and landscapes, establishment of margins with diverse seed mixtures can be recommended for enhancing the development of species richness. However, seed mixtures should include only native species preferably local origin. Management by cutting once a year for 5 years did not result in a decline in dominance of a harmful weed species, Elymus repens, showing that E. repens probably needs cutting more frequently than once per year. Agri-environmental schemes should include long-term contracts with farmers for the establishment, and management by cutting and removal or grazing, of field margins that are several metres wide. In such schemes, the timing and frequency of management should be planned so as not to harm other taxa, such as the insects and birds that are dependent on these habitats. All accidental herbicide drifts to field margins should be avoided when spraying the cultivated area to minimize the negative effects of sprayings on vegetation. The harmful effects of herbicides can be avoided by organic farming methods.