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Nanoteknologia on 1-100 nanometrin kokoluokassa olevien materiaalien rakenneosiin liittyvää ymmärrystä ja kontrollointia, joka mahdollistaa kokoluokalle ominaisten ilmiöiden avulla uudenlaiset sovellukset. Käsite nanoteknologia kattaa nanomateriaalien tutkimukseen ja kehittämiseen keskittyvän nanotieteen sekä valmistukseen tarvittavat tekniikat ja teknologiat. Se sisältää myös nanomittakaavan kuvaamisen, mittaamisen ja mallintamisen. Nanoteknologia on nopeasti kehittyvä ala, jonka avulla valmistettujen tuotteiden määrä kasvaa jatkuvasti. Tulevaisuudessa nanoteknologiassa odotetaan kehitettävän uusia ratkaisuja elektroniikan ja lääketieteen aloille sekä energian tuotantoon ja ympäristön saastumiseen liittyviin ongelmiin. Nanoteknologia on poikkitieteellinen ala, joka pitää sisällään kemian, fysiikan, biologian, lääketieteen ja elektroniikan. Sitä ei ole vielä huomioitu kansallisissa opetussuunnitelmien perusteissa. Nanoteknologian opetus pitäisi integroida osaksi jo koulussa olevia oppiaineita. Suomessa opiskelijoiden kiinnostusta nanoteknologiaa kohtaan on tutkittu vähän ja suomenkielistä opetusmateriaalia on niukasti saatavilla. Tutkimusten mukaan opiskelijat ovat kiinnostuneita nanoteknologian arkielämän sovelluksista esimerkiksi pinnoitteista. Tutkimuksen tavoitteena oli kehittää sellaisia kokeellisia materiaaleja nanoteknologian opetukseen, jotka ovat integroitavissa kemian opetukseen. Kehitettyjen opetusmateriaalin tavoitteena on parantaa luonnontieteellistä osaamista sekä tuoda esille kemian ja teknologian merkitys yhteiskunnalle ja arkielämälle. Kokeelliset oppilastyöt kehitettiin koskemaan kahta aihealuetta: hydrofobiset tekstiilit ja titaanidioksidin fotokatalyysi. Tutkimuskirjallisuuden perusteella oppilaat pitävät kokeellisesta työskentelytavasta ja niiden avulla voi opettaa kemiaa tutkimalla erilaisia ilmiöitä ja sovelluksia. Tutkimus raportoidaan kolmessa osassa ja se jakautuu ongelma-analyysiin, kehittämisprosessiin ja kehittämistuotokseen. Tutkimuksen ensimmäinen vaihe on ongelma-analyysi, joka sisältää aikaisempiin tutkimuksiin keskittyvän teoreettisen ongelma-analyysin ja oppikirjojen sisällönanalyysin. Teoreettisessa ongelma-analyysissä tutustuttiin nanoteknologiaan ja sen opetuksen tutkimukseen. Siinä selvisi, mitä nanoteknologiasta pitäisi opettaa ja miksi aiheen opetus on hyvin vähäistä. Oppikirjojen sisällönanalyysin mukaan nanoteknologiaa käsitteleviä opetusmateriaaleja on hyvin vähän. Ongelma-analyysin avulla selvitettiin kehittämistutkimuksen tarpeet ja tavoitteet. Toinen vaihe on kehittämisprosessi, jossa kuvataan prosessin eteneminen ja tehdyt kehittämispäätökset. Tutkimuksen kolmas vaihe on kehittämistuotos, jossa kuvataan kehitetyt oppimateriaalit. Hydrofobinen tekstiili -työssä esitellään hydrofobisuuden teoriaa ja tutkitaan ilmiötä erilaisilla materiaaleilla. Titaanidioksidin fotokatalyysi -työssä tutustutaan itse ilmiöön ja tutkitaan kiderakenteen vaikutusta fotokatalyyttisen reaktion nopeuteen. Molempien töiden tavoitteena on oppia tutkittavien ilmiöiden kemiaa ja niihin liittyviä nanoteknologian opetuksen ydinajatuksia.

Recently, the world has begun to recognize China as an important aid donor, and with the rising popularity of the Chinese aid model in Africa, it has become a possible alternative to the traditional Western aid. Growing Chinese influence on the African continent has resulted in a biased discussion about Chinese aid, portrayed best by the overly positive Chinese narrative and the negatively inclined Western narrative. This thesis examined the bias present in news articles retrieved from Chinese, Western as well as African sources in relation to Chinese African aid by utilizing content analysis as the main method. The objective was to identify variation within each news source and to place the narratives they represented into respective regional socio-cultural contexts. The research identified a pattern of increasing bias in both the Chinese and Western news sources. The overall tone of the Chinese news articles was mainly positive, whereas the Western news source portrayed a critical and dominantly negative bias in relation to Sino-African cooperation and aid. Both African news sources selected for this research were predominantly neutral. The findings of the research supported the hypothesis that socio-culturally embedded narratives reflect their regional contexts providing varying views towards Chinese aid. Especially in the context of Chinese African aid, the narratives have become increasingly polarized ranging in the far realms of reality, possibly hindering the future of international aid and the development of the African continent.

Tässä tutkielmassa tutkitaan matemaattista neuvotteluteoriaa. Päätulokset ovat Nashin aksioomat toteuttavan neuvotteluratkaisun johtaminen ja sen yksikäsitteisyyden todistaminen sekä Rubinsteinin vuorottelevien tarjousten neuvottelupelin alipelitäydellisen tasapainon ratkaiseminen. Johdantolukua seuraavassa luvussa 2 käsitellään hyötyteoriaa. Odotetun hyödyn ominaisuuden täyttävät preferenssirelaatiot esitetään ja niistä johdetaan von Neumann-Morgenstern-hyötyfunktio. Neuvotteluteoria rakennetaan sen oletuksen varaan, että pelaajien preferenssit ovat ilmaistavissa tällaisten hyötyfunktioiden avulla. Kolmannessa luvussa määritellään ensin kahden pelaajan neuvotteluongelma matemaattisesti. Nashin aksioomat esitetään ja osoitetaan, että Nashin neuvotteluratkaisu on ainoa nämä aksioomat toteuttava neuvotteluratkaisu. Tämän jälkeen analysoidaan kieltäytymispisteen ja riskinkaihtamisen vaikutusta Nashin neuvotteluratkaisuun, sekä tutkitaan muita Nashin neuvotteluratkaisun ominaisuuksia. Epäsymmetrinen Nashin neuvotteluratkaisu esitetään ja todistetaan, että se toteuttaa kaikki Nashin aksioomat lukuun ottamatta symmetrisyyttä. Lopuksi Nashin neuvotteluratkaisu yleistetään monen pelaajan neuvotteluongelmille ja tutkitaan monen pelaajan neuvotteluratkaisun erityispiirteitä. Neljäs luku aloitetaan määrittelemällä täydellisen informaation laajan muodon peli, Nashin tasapaino ja alipelitäydellinen tasapaino. Rubinsteinin vuorottelevien tarjousten neuvottelumalli esitetään täydellisen informaation laajan muodon pelinä, jonka alipelitäydellinen ratkaisu esitetään. Tämän tasapainoratkaisun ominaisuuksia tutkitaan. Lopuksi todetaan, että kun tarjousten välinen aika lähestyy nollaa, niin tämä alipelitäydellinen ratkaisu lähestyy tiettyihin neuvotteluvoimiin liittyvää epäsymmetristä Nashin neuvotteluratkaisua.

Tässä tutkielmassa käsitellään approksimatiivisen Nashin tasapainon löytämisongelmaa laskennallisen vaativuuden kannalta. Vaikka Nashin tasapainon tiedetään olevan aina olemassa, on tasapainon löytäminen osoittautunut vaikeaksi ongelmaksi. Approksimatiivisen Nashin tasapainon löytämisongelma on PPAD-ongelmaluokan täydellinen ongelma. PPAD-luokkaan kuuluvat sellaiset etsintäongelmat, joissa etsittävän ratkaisun olemassaolo seuraa suunnattujen graafien pariteettiargumentista. Suunnattujen graafien pariteettiargumentti toteaa, että jos graafin jokaisen solmun lähtö- ja tuloasteet ovat korkeintaan yksi ja graafissa on tunnettu lähdesolmu, niin graafissa on myös nielusolmu tai toinen lähdesolmu. PPAD-täydellisyyden takia on luultavaa, ettei approksimatiivista Nashin tasapainoa voi löytää polynomisessa ajassa. Tässä kirjoituksessa esitetään uudelleenmuotoiltu ja tarkennettu versio approksimatiivisen Nashin tasapainon löytämisongelman PPAD-vaikeustodistuksesta. Lisäksi esitetään todistus ongelman kuulumiselle luokkaan PPAD. Vastaavaa todistusta ei löydy kirjallisuudesta, vaikka approksimatiivisen Nashin tasapainon löytämisongelman kuuluminen luokkaan PPAD mainitaan.

Tutkimuksessa perehdyttiin sisällönhallintajärjestelmän periaatteisiin ja navigaatioon. Perusteita hyödynnettiin käyttäjätutkimuksessa, jonka tavoitteena oli löytää ongelmakohtia sisällönhallintajärjestelmän navigaationrakennusprosessista. Menujen luominen osoittautui tulosten mukaan testikäyttäjille ongelmalliseksi.

A warming trend of annual average surface temperatures since pre-industrial times has been observed globally. High-arctic area of Svalbard, Norway is undergoing amplified change of annual average temperatures when compared to the global average. Decline of glaciers in western Svalbard has been ongoing for several decades, and in the recent past, rapid biological successions have taken place. These changes have likely had effect on regional scale carbon dynamics at Svalbard’s moss tundra areas. Possibly indicating onset of paludification process of these areas. However, palaeoecological studies from the area are scarce, and the response of high-latitude moss tundra areas to past or ongoing climate change, are still not fully understood. This thesis aimed to bring forward information of changes in recent organic matter and carbon accumulation rates at Svalbard, Norway. Soil profiles were collected from four moss tundra sites, located on coastal areas and fjords descending towards Isfjorden, on the western side of Spitsbergen island. Radiocarbon (14C) and lead (210Pb) dating methods with novel age-depth modelling and soil property analyses, were used to reconstruct recent organic matter and carbon accumulation histories from 1900 AD to 2018 AD. Accumulation histories were supported by meteorological measurements from the area. In addition, annual maximum value Normalized Difference Vegetation Indices for 1985 AD till 2018 AD period were produced, to study vegetation succession in the recent past. Lastly, possibility to predict spatiotemporal variation of soil carbon accumulation with satellite derived vegetation indices was assessed. Development from predominantly mineral soils to organic soils was distinguishable within multiple soil profiles, pointing to potential paludification. Recent apparent carbon accumulation rates showed an increasing trend. Supporting meteorological data and literature suggest that regional abiotic and biotic factors in synergy with weather and climate are contributing to this observed trend. Vegetation indices pointed to major changes in vegetation composition and productivity. However, investigation of relationship between recent carbon accumulation rates and vegetation indices did not produce reliable results. Spatiotemporal heterogeneity of carbon soil-atmosphere fluxes presently imposes large challenges for such modelling. To alleviate this problem, efforts for more efficient synergetic use of field sampling and remote sensing -based material should be undertaken, to improve modelling results.

Nearest neighbor search is a crucial tool in computer science and a part of many machine learning algorithms, the most obvious example being the venerable k-NN classifier. More generally, nearest neighbors have usages in numerous fields such as classification, regression, computer vision, recommendation systems, robotics and compression to name just a few examples. In general, nearest neighbor problems cannot be answered in sublinear time – to identify the actual nearest data points, clearly all objects have to be accessed at least once. However, in the class of applications where nearest neighbor searches are repeatedly made within a fixed data set that is available upfront, such as recommendation systems (Spotify, e-commerce, etc.), we can do better. In a computationally expensive offline phase the data set is indexed with a data structure, and in the online phase the index is used to answer nearest neighbor queries at a superior rate. The cost of indexing is usually much larger than that of performing a single query, but with a high number of queries the initial indexing cost gets eventually compensated. The urge for efficient index structures for nearest neighbors search has sparked a lot of research and hundreds of papers have been published to date. We look into the class of structures called binary space partitioning trees, specifically the random projection tree. Random projection trees have favorable properties especially when working with data sets with low intrinsic dimensionality. However, they have rarely been used in real-life nearest neighbor solutions due to limiting factors such as the relatively high cost of projection computations in high dimensional spaces. We present a new index structure for approximate nearest neighbor search that consists of multiple random projection trees, and several variants of algorithms to use it for efficient nearest neighbor search. We start by specifying our variant of the random projection tree and show how to construct an index of multiple random projection trees (MRPT), along with a simple query that combines the results from independent random projection trees to achieve much higher query accuracy with faster query times. This is followed by discussion of further methods to optimize accuracy and storage. The focus will be on algorithmic details, accompanied by a thorough analysis of memory and time complexity. Finally we will show experimentally that a real-life implementation of these ideas leads to an algorithm that achieves faster query times than the currently available open source libraries for high-recall approximate nearest neighbor search.

The research material consists of 21 dolomite samples taken from the Kalvberget formation in western Sweden. δ13C and δ18O values were analysed from these samples, as well as trace elements and REE composition. Analysis was performed using IRMS, XRD and ICP-MS methods. Main function of trace elemental analysis was to conclude if the isotopical values represented primary marine values or if these values were changed during metamorphical processes. Main question in this thesis was to find out if these samples represented Neoproterozoic cap carbonates and how these samples fit in the global Neoproterozoic δ13C graph. The samples had undergone a green schist-amphibolite facies metamorphosis. The samples were gathered around the Kalvberget formation, representing approx. 30 m of the outcrop. Samples represented thickness of 15 m from the outcrop. Samples K1-K6 had metamorphosed more clearly than samples K7-K21. This was found out from the trace elemental composition. Samples K1-K6 had reacted with silicates, thus changing their primary composition of δ13C and δ18O towards a more negative value. δ13C values of samples K1-K6 were between -3,07 ... -3,34‰ and δ18O values were between -12,04 ... -12,59‰. Samples K7-K21 had δ13C values between +2,07 ... +4,42‰ and δ18O values between -5,94 ... -8,59‰. Indication of metamorphosis affecting the isotopic values in samples K1-K6 led to removal of these samples from the isotopic examination. Samples K7-K21 thus represent primary marine values better. Samples K7-K21 had signs of δ18O values changing because of the interaction with fluids, but the δ13C values represented almost constant values. REE composition showed some signs of detrital matter in the silicate rich samples. Part of the samples were left out from the REE composition examination, as they represented more PAAS content and not primary marine values. Because silicate concentration clearly affected the REE concentrations, all samples with less than 85% carbonate were left out from the REE examination. With these restrictions only samples K7, K11-K16, K18 and K20 were left from examination. REE plots of these samples resembled modern seawater REE plots, although the samples were depleted in HREE compared to modern seawater. From the Ce/Ce* anomaly it was concluded that these samples formed in anoxic environment. Mean value for Ce/Ce* anomaly was 0,94, which differed greatly from modern values. Samples K7-K21 were plotted in global Neoproterozoic δ13C plot. In the plot they placed between the Marinoan and Sturtian iceages 700 – 650 Ma. Conclusion from these results is that these samples do not represent typical cap carbonates formed in Neoproterozoic glaciations, but they are carbonate sediments formed in marine environment between the iceages.

The largest amount of actinides possibly to be released into the environment, however, can be attributed to the geological disposal of spent nuclear fuel. Neptunium is more environmentally mobile than other transuranic elements and thus could escape into the environment. The long-lived neptunium isotope Np-237 (2.14 x 10^6 y) is an actinide of concern in safety assessments of a spent nuclear fuel repositories. It is created by irradiating uranium (U-235 or U-238) in a nuclear reactor and also formed from the decay of americium (Am-241). Radiotoxic Np-237 has been identified as a dominant long-term dose contributor of nuclear waste after one million years. The Np oxidation states under environmental conditions are Np(IV) and Np(V). Under mildly oxic conditions, Np(V) is likely to be the dominant oxidation state. Neptunium is quite soluble, poorly sorbed, and readily mobile under environmental conditions making it highly relevant for research within nuclear safety aspects. Aluminosilicate clay minerals are known to sorb actinides and contribute to actinide immobilization. However, their sorption to these same minerals may also result in colloid-facilitated transport. The bentonite buffer used in the Engineered Barrier System (EBS) consists mainly of montmorillonite and is assumed to be a potential source of colloids. The potential relevance of colloids for radionuclide transport is highly dependent on the stability of colloids in different chemical environments and their interaction with radionuclides. The dimensions of colloids are 1 – 1000 nm and they have strong sorbing properties due to large specific surface area and surface charge. In low salinity groundwater conditions, colloids are mobile unlike rock surfaces. Np(V) sorption behavior on clay minerals has been previously investigated in relatively few studies. In this study, the interaction of neptunium with the clay mineral montmorillonite and bentonite colloid suspension was investigated under simplified but environmentally relevant conditions. Sorption of Np(V) on corundum, Na-montmorillonite and bentonite colloids was studied by conducting batch experiments. Zeta potential measurements were made to obtain data from the surface potential of montmorillonite. Specific surface area, BET, measurements were conducted for montmorillonite and bentonite to get information of the possible sorption capacities. In situ Attenuated Total Reflection (ATR) FT-IR spectroscopy determinations were made to identify neptunium's surface speciation. Aim of the ATR FT-IR measurements is to identify the dominating surface reactions during the sorption of neptunium on mineral and colloid surfaces and to describe them with suitable surface complex formation models. Due to the results the neptunium adsorption onto corundum, montmorillonite and bentonite colloids is detectable. The neptunium adsorption increases as the pH of the solution increases. The sorption is relevant in pH 9 - 11. More isotherm studies are needed to examine the possible saturation of the sorption places for neptunium on the montmorillonite. In addition the reversibility, observed in the ATR FT-IR measurements, of the neptunium sorption should be studied also in batch experiments. The bond between neptunium and corundum or montmorillonite, based on zeta potential and ATR FT-IR measurements, seems to be an inner-sphere complex. For bentonite colloids it was not possible to measure ATR FT-IR because the colloids did not sorb enough neptunium to obtain any spectra. Although the ATR FT-IR measurements showed high reversibility for the bond, indicating it is rather weak inner-sphere complex.