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(2013)Suomen loppusijoituskonseptin (KBS – 3) mukaan ydinvoimaloiden käytetty polttoaine tullaan sijoittamaan Olkiluodon kallioperään noin 400 metrin syvyyteen. Se eristetään elollisesta luonnosta useiden teknisten ja luonnollisten vapautumisesteiden avulla. Puristettu bentoniittisavi on yksi näistä, ja sen tarkoituksena on muun muassa estää mahdollisesti loppusijoituskohteesta vapautuneiden radionuklidien pääseminen kosketuksiin veden kanssa. Bentoniittisavesta voi vapautua suotuisissa oloissa stabiileja kolloidisia hiukkasia, jotka sekoittuvat pohjaveteen. Bentoniittikolloidien pinnan negatiivisen nettovarauksen vuoksi, ne sitovat herkästi esimerkiksi liuoksessa olevia metallikationeja. Mikäli loppusijoituskohteesta pääsisi vapautumaan radionuklideja, on mahdollista, että ne teknisistä vapautumisesteistä huolimatta joutuisivat kosketuksiin pohjaveden kanssa. Suomen loppusijoituskohteen graniittisen kallioperän kivimineraalien ominaisuuksista johtuen pohjaveteen mahdollisesti joutuneet radioaktiiviset metallikationit, esimerkiksi kolmenarvoiset aktinidit, sorboituisivat lujasti kivimineraaleihin tai saostuisivat. Stabiileilla bentoniittikolloideilla on huomattava negatiivinen pintavaraus ja vaikka niilläkin on vuorovaikutuksia kalliomateriaalin kanssa, ne yleisesti hylkivät pohjavesiverkoston kalliopintoja kulkeutuen virtaavan veden mukana pitkiäkin matkoja. Sitoessaan radionuklideja kolloidit voivat täten mobilisoida muutoin erittäin niukkaliukoisia metalleja, jolloin niiden potentiaaliseen kulkeutumiseen liittyvät fysikaaliset ja kemialliset prosessit pohjavesisysteemissä on tunnettava ja huomioitava ydinjätteen loppusijoituksen turvallisuusarvioinnissa. Tämän tutkielman kokeellisessa osiossa selvitettiin bentoniittikolloidien kulkeutumista sekä niiden vaikutusta radionuklidien (Sr-85 ja Eu-152) liikkuvuuteen graniittisissa kivimurske- ja luonnonrakokolonneissa. Kolonnien hydrodynaamiset virtausolosuhteet määritettiin kivimateriaaliin pidättymättömän merkkiaineen (I-125) avulla. ICP – MS:sta analyysia hyödynnettiin määritettäessä bentoniittikolloidien sisältämä alumiinipitoisuus, jonka avulla saatiin laskennallisesti bentoniittikolloidiliuosten sekä kolloidien kulkeutumiskokeiden näytteiden kolloidipitoisuudet. Lisäksi tutkittiin dynaamisen valonsironnan avulla määritettyjen kolloidiliuosten laskentataajuuksien sekä massaspektrometrisesti saatujen kolloidipitoisuuksien välistä riippuvuutta. Bentoniittikolloidien kulkeutumisen havaittiin riippuvan suuresti kolonnin kivimateriaalista, mutta myös eluentin virtausnopeudesta. Kivimurskekolonneilla virtausnopeuksilla 20 – 40 µL/min kolonnien läpi kulkeutui 1,5 – 6,1 % kolonniin syötetyistä bentoniittikolloideista. Rakokolonnin läpi kulkeutui puolestaan huomattavasti suurempi osa kolloideista: virtausnopeudella 10 µL/min yli 25 % ja nopeudella 20 µL/min yli 62 %. Bentoniittikolloidien havaittiin myös kasvattavan selkeästi Sr-85:n liikkuvuutta rakokolonnissa. Kolloideilla ei sen sijaan havaittu olevan vaikutusta Sr-85:n kulkeutumiseen kivimurskekolonneissa. Lisäksi bentoniittikolloidiliuosten dynaamisella valonsironta-menetelmällä saatujen laskentataajuuksien ja ICP – MS:sesti määritettyjen liuosten kolloidipitoisuuksien välillä havaittiin olevan selkeä lineaarinen riippuvuus.
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(2016)Dehydroabietic acid is a natural diterpene readily available from disproportionated rosin. This natural product has attracted the interest of both the synthetic, medical and pharmacological communities due to the wide variety of important biological activities it exhibits. In search for potent pharmaceutical agents, numerous derivatives of dehydroabietic acid have been designed and synthesized accordingly. One key reaction in such syntheses is the benzylic oxidation of positions 7 and 15 in the dehydroabietane core. The oxidized derivatives act as key intermediates in the synthesis of both natural and unnatural dehydroabietanes and related compounds. In the literature part of this thesis, known methods for the benzylic C–H oxidation of dehydroabietanes are presented. In the majority of these methods noxious Cr(VI) compounds are required which produce large amounts of toxic waste. The growing concern on the environmental impact of chemicals has led to an increasing interest towards developing environmentally friendlier oxidation procedures, using cheap and readily available oxidants. Recently, much research has focused on the development of transition metal free approaches for benzylic C–H oxidation. The topic is also discussed in this thesis. In the experimental part transition metal free methods for the benzylic oxidation of dehydroabietic acid derivatives are investigated. An environmentally friendly procedure using sodium chlorite in the presence of aqueous tert-butyl hydroperoxide is described. This procedure resulted in the formation of several variously oxygenated dehydroabietic derivatives which were characterized by IR, NMR and HRMS spectrometry. A manuscript is being prepared based on some of the results presented in this thesis.
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(2014)I avhandlingen definieras cellulära homologigrupper för cellkomplex, och med hjälp av dessa beräknas homologigrupperna för ett antal topologiska rum. Med cellkomplex menar man topologiska rum som byggs upp stegvis genom att börja med en diskret mängd punkter och sedan fästa n-celler ̄ B n till någon del av komplexet som finns från tidigare. Homologigrupper innebär att man associerar en algebraisk invariant, närmare sagt en abelsk grupp med ett topologiskt rum. För att kunna definiera de cellulära homologigrupperna definieras först de singulära homologigrupperna för godtyckliga topologiska rum, varefter de s.k. homologiaxiomen, även kända som Eilenberg–Steenrod-axiomen, presenteras. Med hjälp av homologiaxiomen beräknas de singulära homologigrupperna för enhetssfären S^n, och med hjälp av detta resultat samt med gradberäkningar av avbildningar från enhetssfären till sig själv konstrueras sedan de cellulära homologigrupperna för cellkomplex. Därefter bevisas det faktum att de singulära och cellulära homologigrupperna är isomorfa för alla cellkomplex. Utgående från dessa resultat kan man relativt enkelt beräkna homologigrupperna för många topologiska rum genom att ge rummet en cellstruktur och sedan beräkna rummets cellulära homologigrupper. För att demonstrera hur metoderna som presenterats i avhandlingen kan användas beräknas homologigrupperna för ett antal rum, bl.a. cylindern S^1 × I, torusen S^n × S^n och det reella projektiva n-rummet RP^n. I avhandlingen demonstreras även hur kunskapen om homologigrupperna för sfären S^n kan användas för att bevisa ett antal klassiska topologiska resultat, bl.a. Brouwers fixpunktsats samt det faktum att de Euklidiska rummen R^n och R^m är homeomorfa om och endast om n = m.
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(2016)Over the last 30 years, the geology and paleohydrology has been examined at Olkiluoto as to predict how they may change in the future and affect the final placement of nuclear waste. Some knowledge about the hydrology can be seen directly from present groundwater and the fracture calcite reflect older environments from where they were precipitated. Calcite is the most used fracture mineral within paleohydrogeochemical studies since it easily precipitates during different conditions, including colder climate. The calcite at Olkiluoto has also earlier been examined and dating and grouping of the calcite has been carried out. The aim of the study was to further analyze the trace element composition in fracture calcite samples from earlier studies, in order to understand the influences of groundwater in calcite. The REE concentrations and their anomalies were of special interest. 31 calcite samples from a depth of about 12–660 m under the surface, from 20 different drill cores were analyzed. The calcite had been precipitated at pegmatitc granite, mica gneiss, migmatitic mica gneiss, quartz gneiss and veined gneiss. The calcite was analyzed with ICP-AES (Agilent MP4100), ICP-MS (Agilent 7500ce/cx) and LA-ICP-MS (Coherent GeoLasPro MV and Agilent 7900s). The ICP-AES method was found unsuited for trace element analyses of calcite. The trace element concentrations showed large variations. The later calcite had larger concentrations and more variation towards the surface than deeper in the ground. REE concentrations decreased over depth which can reflect the Ca in the groundwater that increases with depth. LREE showed higher concentrations than HREE since soluble HREE tend to stay in the groundwater during calcite precipitation as LREE migrates to the calcite. Larger LREE concentrations may have occurred from hydrothermal conditions. Usually the calcite had negative Eu anomaly but also positive occurred. Reducing conditions create negative Eu anomalies when Eu3+ takes divalent form. The positive Eu anomalies may also have occurred during hydrothermal conditions or may reflect plagioclase in the bedrock. No direct influence between bedrock and calcite trace element composition could however be determined. The calcite usually lacked Ce anomaly except for a couple near the surface which may be caused by oxidizing conditions where Ce3+ changes to soluble Ce4+. The negative Ce anomalies in calcite from meteoric water, may have inherited the anomaly from earlier seawater. A few La anomalies were observed. Negative La anomaly may occur if La has been taken by other minerals. Usually the calcite lacked Y anomaly except for the oldest calcite that had positive Y anomaly. Acidic conditions tend to cause Fe oxyhydroxation and reduce REE in comparison to Y which may have produced positive Y anomalies. Reducing conditions may also have caused the higher Mn and Fe concentrations in calcite while oxidizing conditions may have created the higher U concentrations. Bacterial activity and clay accumulations during calcite precipitation may have affected Mn concentrations and sulfide precipitation may have affected Fe. The U concentrations in groundwater tend to decrease with depth and at high salinity which may have affected the U concentration in calcite. Variations in Mg concentrations may have been caused by Mg ion exchange. High Sr concentrations may reflect hydrothermal conditions while low Sr concentrations may reflect low temperatures or precipitation of other minerals.
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(2018)Tutkielma perehdyttää lukijan Steinin menetelmään normaaliapproksimaatiolle sekä esittää tämän avulla todistuksen Berry-Esseen-lauseelle. Steinin menetelmä on todennäköisyysteorian piiriin kuuluva nykyaikainen ja tehokas tapa tuottaa ylärajoja kahden eri todennäköisyysjakauman väliselle etäisyydelle. Tutkielmassa esitetään todennäköisyysjakaumien etäisyydelle kolme eniten käytettyä mittaa, jotka ovat Total variation, Kolmogorov sekä Wasserstein-mitat. Tämän jälkeen käydään läpi Steinin menetelmä aloittaen Steinin lemmasta, joka karakterisoi normaalijakauman Steinin operaattorin avulla siten, että operaattorin arvon ollessa nolla, on tarkasteltava jakauma normaali. Seuraavaksi esitetään Steinin yhtälöt, joiden ratkaisujen avulla saadaan Steinin rajoitukset jokaiselle käytetylle kolmelle mitalle. Näiden rajoitusten avulla voidaan päätellä asymptoottinen normaalijakautuneisuus myös silloin, kun Steinin operaattorin arvo on lähellä nollaa. Berry-Esseen-lause on keskeinen raja-arvolause, johon on erityisesti lisätty suppenemisnopeus Kolmogorov-etäisyyden suhteen. Tämä suppenemisnopeus todistetaan tutkielmassa käyttäen hyväksi Steinin menetelmää. Lopuksi käsitellään vielä ylimalkaisesti Steinin menetelmää moniulotteisen jakauman tapauksessa. Huomataan sen olevan hyvin paljon samankaltaista kuin yksiulotteisessa tapauksessa.
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(2017)Ecometric analysis allows one to identify relationships between traits measured in organisms and conditions measured in the organisms' local environment. In developing an ecometric model, one selects phenotypic features of organisms which potentially are adaptations to local environment, aggregates measures of these features by organismal community, and quantitatively relates these to measures of the environment via statistical modeling, such that organismal traits may be used to predict environmental conditions. Once established, these models may be applied to fossil assemblages, to reconstruct local paleoenvironment using traits preserved in the fossil record. In this ecometrics case study, we addressed a number of related research questions: what bioclimatic and threshold measures of temperature and/or precipitation are most closely correlated with large, herbivorous mammal communities' mean hypsodonty (HYP) in sub-Saharan Africa? Do these correlations differ at differing spatial scales; specifically, do mammal communities in Kenya's national parks and reserves together relate differently to local environment than do communities in the Afrotropics ecoregions? Finally, what do results obtained by ecometric analysis suggest concerning organismal evolution and dispersal in sub-Saharan Africa? In pursuing answers to these questions, we also pursued the case study's primary objective: we developed and implemented a set of best practices for ecometric analysis, based on an assessment of the sensitivity of ecometric models to model-building decisions, and to uncertainty in source datasets. Ecometric analyses frequently make use of raster datasets - continuous coverages of temperature, precipitation, productivity, and other environmental properties - in characterizing local environment at study localities. Thus we primarily asked: are ecometric results dependent on raster resolution or resampling algorithm? Results of these sensitivity analyses are encouraging. Using the recommended mean resampling algorithm, change in linear regression equations with raster resolution is predictable, and not significant until very low resolutions, in which the average raster cell area is an order of magnitude or more greater than the average locality area. Moreover, using the recommended area-weighted averaging in calculating environmental observations at localities ameliorates this predicable trend in derived regressions. In working 'behind the scenes' addressing these methodological questions, we enable more informed interpretation of ecometric results, and allow future researchers to proceed to the real business of ecometrics with a vetted set of analytical methods. Moreover, in promoting better understanding of ecometric results, we promote better understanding of the complex relationships between organisms and environment, essential to understanding the biosphere's past and present, and to protecting it in the future.
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(2020)The weathering of concrete by alkali-aggregate reaction is a process of deterioration recognized also in concrete manufactured in Finland. Alkali-aggregate reactions (AAR) are deleterious reactions between the alkali hydroxides (NaOH and KOH) in cement paste and silicon dioxide in aggregate used in concrete. The alkali hydroxide in cement paste will dissolve the crystal structure of silicon dioxide, and the dissolved silicon dioxide hydroxylates to orthosilicic acid. In the presence of impurities, the orthosilicic acid can form covalent bonds and coagulate to form silica gel. The expansion caused by swelling of highly hygroscopic silica gel will lead to excess of yield stress and thus deleterious cracking of concrete. The atomic features of fracture surfaces in natural aggregates will determine their reactivity in concrete. The surface in reactive mineral has unstable equilibrium and has crystallographic defects or insufficient crystal structure. Practically all natural aggregates used in Finnish concrete are heterogeneous mixtures of silicate minerals. The surface features of silicate minerals are composed in various rock forming geological processes. Rocks that are crystallized by slow cooling have more stable equilibrium than rocks that have undergone a low metamorphosis. The geological features and strength measurements are the base of good quality natural aggregate ratings. On the grounds of observations, even the high quality aggregates can cause deleterious alkali-aggregate reactions. It is recommendable to use aggregates that have stable equilibrium state, a low alkalinity cement and additives such as fly ash, blast-furnace slag or silica fume to concrete structures exposed to moisture.
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(2018)This paper studies discourses about suburbs that occur in newspaper writings about 1960s and 1970s infill development. The study aims to find out how writings about infill development are structured in the local newspaper Helsingin Sanomat between 2000 and 2016. The objective is to discover how a high-rise suburb appears as a site for infill development, and what kinds of discourses appear in newspaper writings about infill development. The paper uses discourse analysis to examine how high-rise suburbs built in 1960-1970 are discussed in Helsingin Sanomat between 2000 and 2016, using writings about infill development in Helsingin Sanomat in that period as research material. Due to the choice of newspaper, the addressed suburbs are found in the Helsinki metropolitan area. In recent years, Finnish urbanization has led to regional economic marginalization, which in the Helsinki metropolitan area is concentrated in the high-rise suburbs of the 1960s and 1970s. In addition to economic marginalization, these suburbs are seen to suffer from decreasing and aging population, and a need for renovations. The stated aims of infill development include urban unification and social diversification of the suburbs in order to prevent the cycle of economic marginalization. Combined with deterioration of apartments built in the 1960s and 1970s, structural and social problems in high-rise suburbs have led to a societally challenging situation. The writings contained four discourses about suburbs: potential of the suburbs, defense of the suburbs, the suburb as problematic, and the suburb as a conflict-prone site for infill development. The most powerful discourse was about potential. The defense discourse emphasized the uniqueness and meaningfulness of the suburb as the environment and home of its inhabitants. The conflict discourse refers to writings where the suburb is seen as an infill development site that causes conflict. While most of the newspaper writings mention the age and deterioration of the period’s suburbs, the problem discourse did not dominate the research material. Based on the research, the ways of talking about the suburb depend on the speaker, the speaker’s motives, and the subject. The discourses allowed a crucial observation that the suburb is an arena for wielding power where a contradictory and naïve attitude towards developing suburban social life is a major problem slowing down the prevention of economic marginalization. Because the suburbs of the Helsinki metropolitan area are very different, the research doesn’t reveal what suburbs are really like. Instead, the research shows how the suburbs of the metropolitan area appear in the context of writings about infill development, and reveals the persons featured in writings about infill development as well as the suburbs that are interesting to the media. The study also examines how different parties react to infill development, and seeks to shed light on the motives behind the remarks of different parties.
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(2015)The aim of this thesis is to examine socio-political perspectives of water scarcity in a Moroccan oasis. Drawing from political ecology, it describes the results of a transfer from community-based resource management to institutional hybridity comprising of customary and formal socio-legal institutions and actors, and evaluates how the transfer of authority from customary water user communities to individuals and state organisations, and the adoption or rejection of formal property rights, have affected water access and availability in the oasis. Data was collected during fieldwork in southeast Morocco in October-December 2014 through semi-structured interviews and water point mapping with a GPS device. In total I conducted more than 50 interviews among water users and government authorities gaining access to unpublished secondary data on water resources. Data was analysed applying qualitative and quantitative methods. Results indicate that water scarcity in Ferkla is deepest among those without any permanently available modes of access or only common-property access to water. Customary water rights have lost their value as guarantors of water access due to physical water shortages and legal reforms. Water scarcity is least severe either among individuals who rely on private irrigation with (tube)wells and who have formalised their property, or those who have abandoned farming and rely on tap water. In conclusion, water management laws and policies have targeted and benefited small- and large-scale farmers differently resulting in a clear division between formal water users with improved water security and customary water users with inferior water access and availability. State attempts to improve water management by introducing formal private property rights have resulted in the creation of illegal water users who have been deprived of their customary water and land rights. At the same time, large-scale farmers have gained numerous benefits from formalising their land and water assets resulting in a decreased equity of resource distribution. While customary village councils still retain some power over common-property infrastructure, formal institutions have taken over the management of other modes of water access.
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(2022)This thesis is a review of articles focusing on software assisted floor plan design for architecture. I group the articles into optimization, case based design, and machine learning, based on their use of prior examples. I then look into each category and further classify articles based on dimensions relevant to their overall approach. Case based design was a popular research field in the 1990s and early 2000s when several large research projects were conducted. However, since then the research has slowed down. Over the past 20 years, optimization methods to solve architectural floor plans have been researched extensively using a number of different algorithms and data models. The most popular approach is to use a stochastic optimization method such as a genetic algorithm or simulated annealing. More recently, a number of articles have investigated the possibility of using machine learning on architectural floor plans. The advent of neural networks and GAN models, in particular, has spurred a great deal of new research. Despite considerable research efforts, assisted floor plan design has not found its way into commercial applications. To aid industry adoption, more work is needed on the integration of computational design tools into the existing design workflows.
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(2016)Bézout's theorem, at least the original version, concerns the number of intersection points of two curves in projective plane. The main purpose of this thesis, apart from proving the classical version of Bézout's theorem, is to give multiple generalizations for it. The first proper chapter, Chapter 2, is devoted to the proof of classical Bézout's theorem. In the first two sections of the chapter we define projective and affine plane curves, and show some of their basic properties. In the third section we define the resultant of two polynomials, and use the newly acquired tool to prove the upper bound version of Bézout's theorem. The fourth section discusses the multiplicity of a point of intersection. This multiplicity, dependent of algebraic data associated to the intersection, is needed for stating the equality version of the classical Bézout's theorem. In the fifth section we prove this using properties of the intersection multiplicity proved in the fourth section. The third chapter extends the classical Bézout's theorem beyond its original scope. In Section 3.1 we define a crucial tool, Hilbert polynomial, which allows us to keep track of algebraic information associated to the projective scheme cut out by a homogeneous ideal. This polynomial is not an invariant of the scheme itself; rather it should be thought as containing information concerning both the intrinsic structure of the subscheme, and about how the subscheme is located in the ambient projective space. The second section of the third chapter quickly summarizes the parts of modern algebraic geometry that are of most use later. Section 3.3 gives the first proper generalization of Bézout's theorem. This generalization is more a quantitative than a qualitative one, as it deals with intersections of projective hyperplanes. The fourth chapter gives a generalization of the upper bound version of the Bézout's theorem to a very general case. We define the geometric multiplicity of a closed subscheme of a projective space, and show that it behaves well under intersections. The geometric multiplicity gives an upper bound for the number of components, hence the generalization of inequality version of Bézout. In the final section, 3.5, we define Serre's multiplicity of a component of intersection, and show that the multiplicities given by this formula satisfy the equality version of Bézout's theorem in proper intersections of equidimensional subchemes.
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(2015)Tietovarannoissa esiintyy monesti useita tietueita, jotka kuvaavat samaa objektia. Tässä tutkielmassa on vertailtu näiden tietueiden löytämiseen käytettäviä menetelmiä. Kokeet on suoritettu aineistolla, jossa on 6,4 miljoonaa bibliografista tietuetta. Menetelmien vertailussa käytettiin aineistossa olevien teosten nimekkeitä. Eri menetelmien kahta keskeistä piirrettä on mitattu: löydettyjen duplikaattien lukumäärää ja niiden suhdetta muodostettujen kandidaattien lukumäärään. Kahden menetelmän yhdistelmä osoittautui parhaaksi aineiston deduplikointiin. Järjestetyllä naapurustolla löytyi eniten varsinaisia duplikaatteja, mutta myös eniten irrelevantteja kandidaatteja. Suffiksitauluryhmittelyn avulla löytyi lisäksi joukko duplikaatteja joita muilla menetelmillä ei löytynyt. Yhdessä nämä kaksi menetelmää löysivät lähes kaikki duplikaatit mitä kaikki tutkielmassa verratut menetelmät löysivät. Levenshtein-etäisyyteen perustuvat virhesietoiset menetelmät osoittautuivat tehottomiksi nimekkeiden deduplikoinnissa.
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(2015)Big data creates variety of business possibilities and helps to gain competitive advantage through predictions, optimization and adaptability. Impact of errors or inconsistencies across the different sources, from where the data is originated and how frequently data is acquired is not considered in much of the big data analysis. This thesis examines big data quality challenges in the context of business analytics. The intent of the thesis is to improve the knowledge of big data quality issues and testing big data. Most of the quality challenges are related to understanding the data, coping with messy source data and interpreting analytical results. Producing analytics requires subjective decisions along the analysis pipeline and analytical results may not lead to objective truth. Errors in big data are not corrected like in traditional data, instead the focus of testing is moved towards process oriented validation.
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(2019)The number of bike-sharing systems has increased rapidly during the last decade. These systems expand urban mobility options and provide a solution to the so-called “last-mile” problem. While new bike-sharing systems are opened and current ones expanded in Finland and elsewhere in large numbers, it is important to understand how these systems are used and by whom. Despite the wealth of bike-sharing literature, usage patterns by different user groups are still not yet well studied. This knowledge is needed to ensure that the benefits of bike-sharing systems distribute as evenly as possible to the citizens. In this study, I have employed a person-based approach to study mobility patterns of bike-sharing users in Helsinki. The system in Helsinki was opened in 2016 and the urban bikes quickly became popular among citizens. I have aimed to understand how equally the bike-sharing system in Helsinki is serving the citizens and how different user groups have differed from each other in their use. I have also studied how the system is linking to public transport in Helsinki and compared the bike-sharing system usage and users in Helsinki to other systems internationally. These specific questions stem from the systematic literature review on bike-sharing (n=799), which I carried out before the empirical study. In this study, I have used a dataset provided by Helsinki Region Transport, which contained all the bike-sharing trips (~1.5 million) from 2017. Besides the trip information, the dataset contained the basic demographic information of the user. The results of literature review show bike-sharing systems have been an active and extensive study topic even though the study areas are mostly concentrated to certain cities. Based on the empirical data-analysis, majority of bike-sharing users are young adults between 25-35 years old whereas the share of over 50 year olds is only 12 %. Both men and women use urban bikes actively but men are overrepresented both in the number of users and trips. The use of bikes is not equal but a small minority of users have generated the majority of trips. The users who live inside the bike station coverage area make around 80 % of the trips implying that the proximity of a station has a considerable impact on the use. Trip profiles of those living inside the system coverage area differ considerably from those who live outside the area. For example, the users living inside the area seem to combine urban bikes less with public transport and they use urban bikes relatively more on weekends compared to the other group. The subscription type and use activity are also important factors shaping usage patterns. Then again, age and gender are more important in determining whether someone chooses to become a user than in shaping usage patterns. The use of bike-sharing system in Helsinki has been high even when compared internationally. The results of this study show that the high usage rates still do not necessarily mean that the system would be equally used by citizens. Based on the systematic review, equity is a critical topic to address in relation to bike-sharing users. The user profiles in Helsinki seem to follow similar patterns of bike sharing as found in other cities with an overrepresentation of certain population groups. The use of young adults might promise well for the change of urban mobility. However, it is important to keep promoting cycling to a wider range of the population. The bike-sharing system in Helsinki will expand in 2019 to new areas. Based on the results of this study the expansion seems reasonable as a large part of the users live close to a bike-sharing station. The expansion will then bring the full benefits of bike sharing accessible to a larger group of people in Helsinki. The system seems both to replace and extend the public transport system, which is common to bike-sharing systems in many cities. From the data perspective, the origin-destination type of trip data, which was used in this study, provided a great deal of useful information about users and usage profiles. Even when accounting for limitations in this data type, it is still an excellent addition complementing existing cycling data sources.
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(2020)Tässä pro gradu -tutkielmassa käsitellään binomijakauman luottamusjoukkojen analysointimenetelmiä laajentaen niitä multinomijakauman luottamusjoukkojen tarkasteluun. Tutkielman tarkoituksena on vertailla valikoituja binomi- ja multinomijakaumien luottamusjoukkoja sekä binomijakauman luottamusjoukkojen vertailukriteereitä yleistäen niitä multinomijakauman luottamusjoukoille soveltuvin osin. Luottamusjoukkojen määrittelyssä on käytetty frekventististä päättelyä. Vertailuun valikoitujen vakiintuneiden binomijakauman luottamusjoukkojen lisäksi tyossä määritellään kaksi muuta luottamusjoukkoa. Näitä luottamusjoukkoja vertaillaan kahdeksan esitellyn vertailukriteerin perusteella. Luottamusjoukkojen tutkimisessa erityisesti peittotodennäköisyys osoittautuu hyödylliseksi menetelmäksi. Multinomijakauman luottamusjoukkoja esitellään kolme yleisesti käytössä olevaa sekä yksi vertailuun kehitetty luottamusjoukko. Multinomijakauman luottamusjoukoille yleistetään peittotodennäköisyys, jonka avulla luottamusjoukkoja analysoidaan. Esiteltyjä luottamusjoukkoja vertaillaan yhden yleistetyn kriteerin avulla. Tuloksina käydään läpi esitellyt luottamusjoukot, sekä arvioidaan niiden soveltuvuutta erilaisiin tutkimustilanteisiin pienillä havaintomäärillä. Luottamusjoukkojen peittotodennäköisyyden avulla joukkojen erilaiset ominaisuudet erottuvat selkeästi. Arvioidut vertailukriteerit yleistyvät multinomijakauman luottamusjoukoille pääosin hyvin.
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(2021)Carbon monoxide (CO) is a chemically reactive trace gas in the atmosphere, indirectly affecting radiative balance. The oxidation of CO with hydroxyl radical (OH) is the large sink of atmospheric CO. The reactions of CO and OH decrease the atmospheric capacity to oxidize atmospheric methane (CH4), hence indirectly extends the lifetime of CH4 in the atmosphere. In addition, CO oxidation increases the abundance of tropospheric ozone (O3). CH4 and O3 are both very strong greenhouse gases, and it has been estimated that the cumulative indirect radiative forcing of CO can be even more significant than the third most powerful greenhouse gas, nitrous oxide. This study studied CO fluxes in four different ecosystems: a boreal forest, a boreal fen, a cropland in the boreal region, and a sisal plantation in the semi-arid tropical zone. All the ecosystems were CO sources during the growing season from May to August, and ecosystems showed strong seasonal variation. Fluxes had a regular diurnal cycle, peaking at noon and zero flux or small uptake at night. The main drivers for the CO emissions were radiation and air temperature. The strong correlation between radiation and CO flux proved that photodegradation was an important process in biogenic CO emissions. Radiation and air temperature were used in a simple linear regression model to estimate the biogenic CO emissions in the study sites. The model was trained for Hyytiälä data in 2016, tested for the rest of the data from Hyytiälä in 2015 and 2017 and other sites. The chamber measurements showed that soils were CO sinks and CO emissions were mainly from vegetation. Generally, in many upscaling models of CO, soil consumption is considered significantly larger than photodegradation. This study showed that many terrestrial ecosystems can be sources of CO, even though there are generally considered as a sink of CO. There is a need for ecosystem-scale flux measurements in other ecosystems and latitudes to understand better the global CO budget.
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(2020)Biogenic Volatile Organic Compounds play a major role in the atmosphere by acting as precursors in the formation of secondary organic aerosols and by also affecting the concentration of ozone. The chemical diversity of BVOCs is vast but global emissions are dominated by isoprene and monoterpenes. The emissions of BVOCs from plants are affected by environmental parameters with temperature and light having significant impacts on the emissions. The Downy birch and Norway spruce trees consist of heavy and low volatile compounds but published results are limited up to observing sesquiterpenoid emissions from these two trees. In this study, the Vocus proton-transfer-reaction time-of-flight mass spectrometer is deployed in the field to examine BVOC emissions from Downy birch and Norway spruce trees. With higher mass resolution, shorter time response and lower limits of detection than conventional PTR instruments, the Vocus can effectively measure a broader range of VOCs. For the first time, real-time emissions of diterpenes and 12 different oxygenated compounds were observed from birch and spruce trees. The emission spectrum of birch was dominated by C10H17+, while for spruce C5H9+ contributed the most. The sum emissions of oxygenated compounds contributed significantly to the observed total emissions from both the trees. The emission rates of all compounds varied dramatically throughout the period due to fluctuations in temperature and light. Due to lack of data from spruce, conclusive results for temperature and light response on terpene emissions could not be drawn. For birch, the emission rates were well explained by the temperature and temperature-light algorithms. The terpene emissions modelled using both algorithms correlated similarly with experimental data making it difficult to decisively conclude if the emissions originated from synthesis or pools.
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(2020)Tutkielman kirjallisuusosuudessa on käyty läpi erilaisia kaupallisia biopolymeerejä, niiden synteesiä, käyttöä ja biohajoamista. Tutkielman pääpaino on erilaisten materiaalien biohajoamisessa ja näiden materiaalien kaupallisessa käytössä. Biohajoamisen evaluointiin tarkoitettuja standardeja, tutkimusmenetelmiä ja hyväksyntäkriteerejä on esitelty laajasti. Tutkimusosuudessa on valmistettu PLA:n ja PBAT:n seoksesta puukomposiitti ja materiaalin termomekaaniset ominaisuudet on karakterisoitu. Tavoitteena oli luoda biohajoava materiaali, jonka ominaisuudet ovat sellaisia, että sen kaupallinen hyödyntäminen kertakäyttömuovin korvikkeena on järkevää. Materiaalin mekaaniset ominaisuudet karakterisoitiin lopputuotteen kestävyyden, ja sulaominaisuudet kaupallisen tuotannon mahdollistamisen takia. Termomekaanisia analyysejä tehtiin materiaalin säilyvyyden ja lämpöominaisuuksien karakterisoimiseksi. Työssä on tutkittu myös puhtaan PLA/puukomposiitin biohajoamista meriympäristössä. Tutkimuksen tuloksena saatiin luotua riittävällä nopeudella biohajoava puukomposiitti, jonka mekaaniset ominaisuudet ovat riittäviä korvaamaan erilaisia kertakäyttöisiä muovituotteita ja joka on prosesoitavissa nykyisillä ekstruusiolaitteistoilla.
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(2021)Acute lymphoblastic leukemia (ALL) is a hematological malignancy that is characterized by uncontrolled proliferation and blocked maturation of lymphoid progenitor cells. It is divided into B- and T-cell types both of which have multiple subtypes defined by different somatic genetic changes. Also, germline predisposition has been found to play an important role in multiple hematological malignancies and several germline variants that contribute to the ALL risk have already been identified in pediatric and familial settings. There are only few studies including adult ALL patients but thanks to the findings in acute myeloid leukemia, where they found the germline predisposition to consider also adult patients, there is now more interest in studying adult patients. The prognosis of adult ALL patients is much worse compared to pediatric patients and many are still lacking clear genetic markers for diagnosis. Thus, identifying genetic lesions affecting ALL development is important in order to improve treatments and prognosis. Germline studies can provide additional insight on the predisposition and development of ALL when there are no clear somatic biomarkers. Single nucleotide variants are usually of interest when identifying biomarkers from the genome, but also structural variants can be studied. Their coverage on the genome is higher than that of single nucleotide variants which makes them suitable candidates to explore association with prognosis. Copy number changes can be detected from next generation sequencing data although the detection specificity and sensitivity vary a lot between different software. Current approach is to identify the most likely regions with copy number change by using multiple tools and to later validate the findings experimentally. In this thesis the copy number changes in germline samples of 41 adult ALL patients were analyzed using ExomeDepth, CODEX2 and CNVkit.
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