Browsing by discipline "none"
Now showing items 81-100 of 270
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(2020)The design of instructional material affects learning from it. Abstraction, or limiting details and presenting difficult concepts by linking them with familiar objects, can limit the burden to the working memory and make learning easier. The presence of visualizations and the level to which students can interact with them and modify them also referred to as engagement, can promote information processing. This thesis presents the results of a study using a 2x3 experimental design with abstraction level (high abstraction, low abstraction) and engagement level (no viewing, viewing, presenting) as the factors. The study consisted of two experiments with different topics: hash tables and multidimensional arrays. We analyzed the effect of these factors on instructional efficiency and learning gain, accounting for prior knowledge, and prior cognitive load. We observed that high abstraction conditions limited study cognitive load for all participants, but were particularly beneficial for participants with some prior knowledge on the topic they studied. We also observed that higher engagement levels benefit participants with no prior knowledge on the topic they studied, but not necessarily participants with some prior knowledge. Low cognitive load in the pre-test phase makes studying easier regardless of the instructional material, as does knowledge on the topic being studied. Our results indicate that the abstractions and engagement with learning materials need to be designed with the students and their knowledge levels in mind. However, further research is needed to assess the components in different abstraction levels that affect learning outcomes and why and how cognitive load in the pre-test phase affects cognitive load throughout studying and testing.
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(2020)The geochemical regolith data gathered from Dzhumba, a gold prospect in eastern Kazakhstan, was analyzed using factor analysis and then integrated into ArcGIS as spatial data. Principal axis factoring method was used for factor extraction combined with varimax orthogonal rotation and Kaiser normalization. Five clear factors were extracted from the data set of 47 elements in 3942 regolith samples. Kriging interpolation was used to generate spatial data surfaces from factor scores. The generated factors are composed of the geochemical associations in the raw data, and represent the underlying geological processes and formations of the area. The fourth factor generated represents gold mineralization with As, Sb, Au, Zr, Sc, Mn, Mo, Cu, K and Ni being the elements that are positively loaded onto factor 4. Therefore, single element maps of these elements have been produced alongside the factor maps in order to examine factor 4 more intensely. Also maps about structural geology and alteration in the Dzhumba project area have been produced in order to give better understanding of the factor maps. The data suggests that the deposit type is an orogenic gold deposit. Other factors created interesting results as well, and they gave information about the different geological units of the area. Factor 1 represents granitic rocks by their feldspar and trace element content, factor 2 represents black shales with possible mafic rock constituents, factor 3 represents a sulfide rich mafic mineral group or graphitic rocks that are most likely black shales and factor 5 possibly represents calcite alteration. Factor 4 is the main interest of this study. The most intense loadings for factor 4 are in Brigadnoe, Svistun and Dzhumba with a small peak in Belyi. Single element map for gold mostly corresponds to factor 4 for Svistun and Dzhumba, but Brigadnoe is represented with a small peak. However, gold has a major presence in Fedor-Ivanovskoe, which is absent from factor 4. Further exploration in Fedor-Ivanovskoe could be performed in order to clarify if this is due to an unrelated gold-only deposit or some other event. Possible future exploration in the area could benefit from factor 4 results, using As and Sb, or a combination of As, Sb, Zr, Sc, Mn, Mo, Cu, K and Ni as pathfinders for possible gold occurrences.
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(2020)Federated learning is a method to train a machine learning model on multiple remote datasets without the need to gather the data from the remote sites to a central location. In healthcare, gathering the data from different hospitals into a central location can be a difficult and time-consuming task, due to privacy concerns and regulations regarding the use of sensitive data, making federated learning an attractive alternative to more traditional methods. This thesis adapted an existing federated gradient boosting model and developed a new federated random forest model and applied them to mortality prediction in intensive care units. The results were then compared to the centralized counterparts of the models. The results showed that while the federated models did not perform as well as the centralized models on a similar sized dataset, the federated random forest model can achieve superior performance when trained on multiple hospitals' data compared to centralized models trained on a single hospital. In scenarios where the centralized models had data from multiple hospitals the federated models could not perform as well as the centralized models. It was also found that the performance of the centralized models could not be improved with further federated training. In addition to practical advantages such as possibility of parallel or asynchronous training without modifications to the algorithm, the federated random forest performed better in all scenarios compared to the federated gradient boosting. The performance of the federated random forest was also found to be more consistent over different scenarios than the performance of federated gradient boosting, which was highly dependent on factors such as the order with the hospitals were traversed.
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(2020)Violence against women causes serious health and psychological impacts and is pervasive in society. This is partly due to gender and social norms. These have been addressed through educational campaigns, aiming to overcome pluralistic ignorance - when people wrongly believe that they feel differently from their peers, even though they are behaving in the same way. Pluralistic ignorance can prevent people intervening or reporting gender-based violence. This project proposes that public space can also play a role in overcoming pluralistic ignorance, through the medium of street political messages, such as stickers and graffiti. To show that this is possible, fieldwork exploring the existing feminist street messaging in Kallio and interviews based on this data were conducted. The interviews asked what role street media can play in spreading feminist messages, what the advantages and disadvantages of street media are and whether the existing street messaging in the Kallio district can help with overcoming pluralistic ignorance around gender-based violence issues. Four key aspects of theory are used in the thesis. Firstly, an exploration of gender-based violence literature found that domestic violence is a difficult topic to get people to engage with and that using outreach tools can spark important conversations. Secondly, a sociological study of pluralistic ignorance found that educational campaigns are the main route taken to address gender-based violence issues and that there is a gap in studies of pluralistic ignorance when considering the role of everyday public life in addressing these issues. Thirdly, public space is explored, determining that it can play a key role in feminist activism because it provides an open forum and an anonymity which prevents the activist from being verbally abused or silenced. Finally, street media were explored. This found that the eye-catching and unexpected nature of the media can catch people’s attention. In the fieldwork, seventy feminist street messages were found in Kallio, with a variety of agendas. The majority were in sticker form and located on posts on the streets of Kallio. Interviews conducted with activists and a community group determined the importance of stickers in spreading feminist messages. Street messaging had advantages of being easy to spread, having high outreach, anonymity and as conversation starters. Identified disadvantages included illegality, the potential to provoke people or trigger trauma, limited space for text and that messages can often be too niche for a general audience. The study concludes that street messaging can help overcome pluralistic ignorance by acting as a conversation starter and as a confidence boost to people. However, the results indicate that street media alone will not be enough to address pluralistic ignorance and that wider conversation is needed to have a real impact.
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(2019)Diblock copolymers, poly(lactide)-block-poly(2-isopropyl-2-oxazoline) (PiPOx-b-PLA) and n-octadecyl poly(2-isopropyl-2-oxazoline) (PiPOx-C18), were characterized using the steady-state fluorescence with two fluorescence probes, pyrene and (1,6-diphenyl-l,3,4-hexatriene) (DPH), to investigate the core structure of the particles formed by the polymers. The two enantiomers of PiPOx-b-PLA, which are PiPOx-PLLA and PiPOx-PDLLA, reflected very different features in terms of polarity of the micellar core and the partitioning equilibrium constants of pyrene (Kv). This suggests that the core of the particles formed by PiPOx-PDLLA has higher polarity due to high water content in the range of the polymer concentrations from 0.03 g/L to 3 g/L, and more pyrene molecules are bound to the particles. Furthermore, the core of the particles formed by PiPOx-PDLLA reveals rigidity lower than that of PiPOx-PLLA, which is supported by the low anisotropy value (r) of DPH. r did not change upon heating from 15 ⁰C to 65 ⁰C for the PiPOx-PLLA particles. A slight decrease of r occurred above 50 ⁰C for the PiPOx-PDLLA particle. The PiPOx-C18 micelles exhibit higher critical micellar concentration (CMC), smaller Kv, and softer core in comparison to the PiPOx-b-PLA micelles. These differences owe to the nature of the alkyl chain end. Loading and release of a hydrophobic drug, curcumin, to/from the PiPOx-PLLA and PiPOx-PDLLA micelles were investigated by means of the steady-state fluorescence. The release test was conducted using the dialysis bag method. The PiPOx-PDLLA particles encapsulated more curcumin with encapsulation efficiency (EE) value being 98% while the curcumin-to-polymer ratio was 1:20. Curcumin intake of the PiPOx-PLLA particles was lower under the same condition (EE = 56%). The PiPOx-PDLLA particles show excellent ability of trapping curcumin. PiPOx-PDLLA bear 70% of curcumin inside the dialysis bag after 50 h, whereas 40% of curcumin was discharged from dispersions of PiPOx-PLLA. Precipitation of curcumin was observed in presence of PiPOx-PLLA in 4 days. No curcumin precipitating from the PiPOx-PDLLA dispersion occurred and a decrease in the intensity of curcumin owed to the degradation of curcumin. Finally, all the phenomena observed are well illustrated by the hypothesis of the morphology of the particles formed by PiPOx-PLLA and PiPOx-PDLLA. The particle formed by PiPOx-PDLLA consists of a loose hydrophobic core with hydrated tails extending to the aqueous phase, whereas the core of PiPOx-PLLA particle is dense.
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(2020)Kohdennettuun PET-kuvantamiseen sopivia spesifisiä radiolääkeaineita on kehitetty viimeisen kymmenen vuoden aikana aktiivisesti. Tiettyyn reseptorityyppiin sitoutuvien biomolekyylien käyttö kuvantamisessa sujuvoittaa syöpien diagnosointia ja nopeuttaa hoitosuunnitelmia. Tällaisia molekyylejä ovat muun muassa vasta-aineet, peptidit ja oligonukleotidit. Biologisesti aktiivisia molekyylejä on pitkään radioleimattu radiometalleilla, mutta tarve 18F-radioleimauksille on noussut radionuklidin positroniemissio-ominaisuuksien takia. Biomolekyylien radiolääkeainekehityksessä kulmakiveksi on noussut makromolekyylien herkkyys tyypillisille 18F-radio-leimausolosuhteille. Biomolekyylejä voidaan radioleimata joko suoraan biomolekyyliin tai epäsuoraan prosteettiseen ryhmän avulla. Kliinisesti käytössä jo pitkään olleita 18F-radiolääkeaineita, kuten [18F]fluori-deoksi-glukoosi ([18F]FDG) ja [18F]-N-sukkinimidyyli-fluori-bentsoaatti ([18F]SFB), on hyödynnetty PET-kuvantamisessa biokonjugoituna sopivaan peptidiin. Isotooppiseen 19F-18F vaihtoreaktioon (IEX, engl. isotopic exchange) soveltuvat prosteettiset ryhmät soveltuvat hyvin suoraan biomolekyylien radioleimauk-seen, kun ne on valmiiksi biokonjugoitu molekyylin klik-reaktiolla. Tällaisia prosteettisia ryhmiä ovat muun muassa Si-18F-, B-18F- ja Al-18F-sidoksia sisältävät molekyylit. [18F]Fluoriboraatit ovat osoittautuneet hyödyllisiksi työkaluiksi peptidien 18F-leimaukseen. Erityisesti alkyynirakenteista kahtaisionista [18F]alkyyliammonium-metyylitrifluoriboraattia ([18F]AMBF3 eli [18F]1) on radioleimattu biokonjugoituna useaan eri peptidiin hyvällä in vivo stabiilisuudella. [18F]1 biokonjugointi peptidiin perustuu kuparikatalysoituun atsidi-alkyyni-sykloadditioon. Tämän maisterin-tutkielmatyön tarkoituksena oli optimoida automatisoitu radiosynteesi [18F]1:lle. Lisäksi työssä määritettiin radioleimausolosuhteet kupa-rikatalysoidun atsidi-alkyyni sykloadditiossa muodostetulle trifluoriboraatin ja tetratsiinin johdannaiselle, [18F]AMBF3-PEG4-mTz:lle ([18F]F2). [18F]1 syntetisoitiin kaksivaiheisella synteesillä booripinakoliesterin substituutioreaktiolla, minkä jälkeen booripinakoliesteri fluorattiin trifluoriboraatiksi kaliumbifluoridilla, KHF2, 72 % saannolla. [18F]2 syntetisoitiin [18F]1:sta ja mTz-PEG4-atsidista kahden tunnin kuparikatalysoidulla klik-reaktiolla huoneenlämmössä 63 % saannolla. Molemmat prosteettiset ryhmät 18F-radioleimattiin IEX-reaktiolla pyridatsiini-HCl-puskuriliuoksessa (1.0 M, pH 2.0), johon radioaktiivinen [18F]fluoridi lisättiin µQMA-patruunasta konsentroituna 0,9 % NaCl-liuoksessa 10-20 µl:ssa. [18F]1 radioleimattiin toistuvasti automatisoidulla radiosynteesillä 47 % radiokemiallisella saannolla (RCY) 99,9 % puhtaudella radio-TLC-määrityksen perusteella (TLC, Thin Layer Chromatography = Ohutlevykerroskromatografia). [18F]2 radioleimattiin manuaalisella pipetoinnilla toistettavasti kohtuullisella RCY:llä 23-38 % puhtausluokassa 95-99,2 %. Molaariset aktiivisuudet (MA) olivat suoraan verrannollisia käytettyyn lähtöaktiivisuuteen: esimerkiksi yli 1 GBq lähtöaktiivisuudella [18F]1:n MA oli vastaavasti 1,12-1,22 GBq/µmol. Merkkiaineiden lipofiilisuusmääritysten perusteella LogD-arvoiksi saatiin: [18F]1:lle -1,28 ± 0,33 ja [18F]2:lle -0,43 ± 0,25. [18F]1 toimii hyvänä prosteettisena ryhmänä peptidien 18F-radioleimauksessa useisiin eri kuvantamiskäyttötarkoitukseen. Sen farmakologisia ja toksikologisia profiileja on tosin vielä tutkittava ennen kliinistä käyttöön ottoa. Tutkielmassa optimoitiin radiosynteesi, joka mahdollistaa myös muiden potentiaalisten trifluoriboraattien 18F-radioleimauksen säteilyturvallisesti. [18F]Fluoridin konsentrointi on radiosynteesin haastavin vaihe, joka voitaisiin korvata sopivilla vaihtoehtoisilla menetelmillä vielä tehokkaammaksi kuin µQMA-patruunalla.
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(2020)Terrestrial cosmogenic nuclides can be used to date glacial events. The nuclides are formed when cosmic rays interact with atoms in rocks. When the surface is exposed to the rays, the number of produced nuclides increases. Shielding, like glaciation, can prevent production. Nuclide concentration decreases with depth because the bedrock attenuates the rays. The northern hemisphere has experienced several glaciations, but typically only the latest one can be directly observed. The aim of the study was to determine if these nuclides, produced by cosmic rays, can be used to detect glaciations before the previous one by using a forward and an inverse model. The forward model predicted the nuclide concentration with depth based on a glacial history. The longer the exposure duration was, the higher was the number of nuclides in the rock. In the model, it was possible to use three isotopes. Be-10, C-14 and Al-26. The forward model was used to produce synthetic samples, which were then used in the inverse model. The purpose of the inverse model was to test which kind of glacial histories produce similar nuclide concentrations than what the sample had. The inverse model produced a concentration curve which was compared with the concentration of the samples. The misfit of the inverse solution was defined with an “acceptance box”. The box was formed from the thickness of the sample and the corresponding concentrations. If the curve intersected with the box, the solution was accepted. Small misfit values were gained if the curve was close to the sample. The idea was to find concentration curves which have as similar values as the samples. The inverse model was used in several situations, where the number of limitations was varied. If the timing of the last deglaciation and amount of erosion were known, the second last deglaciation was found relatively well. With looser constraints, it was nearly impossible to detect the past glaciations unless a depth profile was used in the sampling. The depth profile provided a tool to estimate the amount of erosion and the total exposure duration using only one isotope.
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(2020)Tämä tutkimus on osa DNA-oligonukleotidien liuossynteesin menetelmien kehittämishanketta. Kemiallinen oligonukleotidisynteesi tehdään tyypillisesti kiinteän kantajan päällä. Suurempien ainemäärien valmistamiseksi liuosfaasissa toimiva menetelmä olisi kuitenkin toivottava. Vaiheittain etenevässä synteesimenetelmässä on keskeistä löytää yhteensopiva sarja suojaryhmiä. Kiintokantaja- ja liuosfaasisynteeseissä suojaryhmiltä vaaditaan erilaisia ominaisuuksia, koska reaktiot suoritetaan eri tavalla. Liuosfaasisynteesissä reaktioiden tasapaino pitää asettua vahvasti tuotteiden puolelle, koska toisin kuin kiintokantajamenetelmässä sivutuotteita ei voi huuhtoa pois ja reagenssien määrää ei voida pitää niin vakaana. Olemme kehittäneet sarjan suojaryhmäreagensseja nukleosidien 5’-hydroksyylisuojaryhmän suojaamiseksi asetaalina. Asetaalisuoja voidaan liuossynteesissä poistaa kokonaan ja suojaryhmällä on tarkoitus korvata samaan ortogonaaliseen ryhmään kuuluva trityylisuojaus, joka ei soveltunut liuosfaasisynteesin. Nyt esiteltävässä työssä paneudutaan menetelmään soveltuvien 2’-deoksinukleosidi 3’-O-vetyfosfonaattiestereiden valmistamiseen. Fosfori(V)-yhdisteiden reaktiivisuus ei useinkaan ole riittävä fosfaattiryhmän liittämiseen kohdemolekyylissä olevaan hydroksyyliryhmään, joten fosforyloinnissa käytetään usein fosfori(III)-yhdisteitä, kuten fosfiitteja, fosforamidiitteja ja vetyfosfonaatteja. Liitettävä fosfaattiryhmä, kuten monet muut reaktiiviset funktionaaliset ryhmät, suojataan usein suojaryhmillä. Suojaryhmillä voidaan niiden päätarkoituksen lisäksi muokata molekyylin rakennetta ja fysikokemiallisia ominaisuuksia. Reaktiotuotteen liukoisuutta voidaan muokata suojaryhmillä sen eristyksen tai jatkoreaktioiden helpottamiseksi. Tutkielman kirjallisuusosassa tarkastellaan suojaryhmiä, joita on käytetty fosfaateille ja vetyfosfonaateille. Fosfaattisuojaryhmällä voidaan mahdollisesti suojata vetyfosfonaattimonoesteri diesteriksi, jolloin negatiivinen varaus saadaan naamioitua ja tuotteesta tulisi lipofiilisempi. Kokeellisen tutkimuksen tavoite oli valmistaa 5’-asetaalisuojattuja tymidiinin vetyfosfonaatteja difenyylivetyfosfonaattireagenssilla. Saanto jäi hyvin pieneksi, koska tuote osoittautui liian vesiliukoiseksi pienikokoisen ja heikosti lipofiilisen asetaalisuojan kanssa. Ratkaisuksi kehitettiin menetelmä, jossa muodostettiin ensin tymidiinin vetyfosfonaattidiesteri syanoetanolin kanssa. Vetyfosfonaattidiesteri on todennäköisesti varauksettomana tuotteena ja lisätyn alkyyliryhmän kanssa poolittomampi. Suojaryhmän avulla tymidiinin vetyfosfonaatti voitaisiin eristää, jonka jälkeen ryhmä poistetaan emäksellä β-eliminaatioreaktiossa. Vetyfosfonaattidiesterin eristäminen ja suojaryhmän poistaminen vedettömissä olosuhteissa helpottaa vetyfosfonaattimonoesterin talteenottoa. Vaihtoehtoisesti tymidiinin liukoisuusominaisuuksia muokattiin suojaamalla tymiinin 4-O β-eliminoituvalla poolittomalla suojaryhmällä. Fosfitylointimenetelmä ei tarvitsisi muokkausta jos, emäsmuokattu tymidiini osoittautuu veteen liukenemattomaksi.
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(2019)Atmospheric aerosols affect the Earth's radiative balance, visibility and human health. Therefore the formation processes and growth of these particles are important and should be studied to understand how human and natural processes affects these processes. One poorly understood and relatively little studied part of aerosols is particulate organic nitrates (pONs). These pONs are mostly formed during nighttime when NOx, mainly emitted from fossil fuel combustion and industrial processes, and volatile organic compounds (VOCs), from both natural and anthropogenic sources, reacts in the atmosphere. The quantification of these pONs is still hard due to instrumental restrictions, although much improvement has happened during recent years. One main reason for these challenges is the difficulty to separate inorganic nitrates from organic nitrates with real-time instruments. During this work, we generated pure pON in well controlled laboratory conditions and sampled it with an Aerosol Mass Spectrometer (AMS), an instrument widely used for measuring the chemical composition of atmospheric aerosols. We used four different pON precursors to generate pON. I investigated the fragmentation patterns of pON detected by the AMS, utilizing the high resolution of the newest model of the AMS. As older versions of the AMS has difficulties to separate nitrate-containing organic fragments due to lower resolution than the AMS I used, I was able to study pON mass spectrum with better resolution than anyone before me. I found mass spectral differences for the different pON precursors, and was able to find unique fragments for some of the pON precursors that possibly can be used as marker fragments.
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(2020)Ligniini on maailman yleisin biopolymeeri selluloosan jälkeen. Kuitenkin puiden biomassan rakenteen vuoksi ligniinin eristäminen muusta biomassasta ei ole yksinkertaista vaan vaatii erityisesti sitä varten kehitettyjä menetelmiä. Lisäksi ligniinin heterogeenisen rakenteen vuoksi sen hyödyntäminen kemiallisesti ei ole helppoa, vaan biomassan jalostusprosesseissa ligniini päätyy sivuvirtojen mukana poltettavaksi. Ligniinin yleisyyden ja sen uusiutuvuuden vuoksi ligniinin käytöstä ollaan kiinnostuneita ja ligniinistä yritetäänkin saada sitä muokkaamalla käyttökelpoista materiaalia teollisuuden eri tarpeisiin. Japanilainen professori Masamitsu Funaoka on kehittänyt menetelmän, joka pyrkii samanaikaisesti eristämään ligniinin muusta biomassasta sekä muokkaamaan ligniinin rakennetta niin, että sitä voitaisiin hyödyntää erilaisissa sovelluksissa tekemällä siitä homogeenisempaa. Funaokan menetelmässä ligniinin bentsyyliseen α-asemaan liitetään selektiivisesti haluttu fenolinen yhdiste, joka lisää ligniinissä olevien aromaattisten hydroksyyliryhmien määrää ja katkoo ligniiniyksikköjen välisiä sidoksia alentaen ligniinin moolipainoa. Tämän tutkielman kirjallisessa osassa perehdytään Funaoka-menetelmään lignoselluloosamassan fraktionnissa. Lisäksi tarkastellaan saatujen lignofenolien rakenteellista muokkaamista, potentiaalisia käyttökohteita ja niistä jatkokäsiteltyjä materiaaleja. Kokeellisessa osassa puolestaan analysoidaan eräitä kotimaisia biomassan prosessoinnissa syntyneiden sivuvirtojen biomassatähteitä, erityisesti kiinnittäen huomiota biomassanäytteiden ligniinipitoisuuksiin. Biomassanäytteiden kemiallisen karakterisoinnin lisäksi kokeellisessa osassa testattiin ligniinipitoisten biomassanäytteiden fraktiointia Funaoka-menetelmällä ja tämä toistettiin myös näytteiden lähtöaineille eli havupuuhakkeelle.
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(2020)Kieli on keskeinen osa oppimista ja niitä ei voida erottaa. Tieteellä on oma kieli, joka eroaa merkittävästi opiskelijoiden tuntemasta arkikielestä monella tapaa. Tieteellinen kieli sisältää suuren määrän informaatiota lyhyessä tekstissä, sisältää opiskelijoille tuntemattomia termejä ja myös lauserakenne on erilainen. Opiskelijoiden tieteen oppimisessa tieteellisen kielen oppiminen onkin yksi suurimmista ongelmista. Tämän vuoksi tulevien fysiikan aineenopettajien kielellisten ilmaisujen tutkiminen on tärkeää. Opinnäytetyössä analysoidaan fysiikan aineenopettajaopiskelijoiden tuottamia tekstejä fysiikan aineenopettajakoulutuksen kurssilta. Aineisto koostuu 12 tekstistä kuudelta eri fysiikan aineenopettajaopiskelijalta. Tarkoituksena on vastata tutkimuskysymyksiin: 1. Miten voimme analysoida aineenopettajaopiskelijoiden sanaston käyttöä? ja 2. Miten fysiikan aineenopettajaopiskelijat käyttävät kaksoisrakokokeen sanastoa? ja kehittää luotettava ja toistettavissa oleva analyysiprotokolla, jolla voidaan analysoida suomenkielisiä tekstejä. Analyysinlopputulos on yksinkertaistettu muoto aineistosta, jota voidaan analysoida tulevaisuudessa mahdollisesti tietokoneella. Teoriaosassa käsitellään lisäksi käsitteitä, käsitteellistä muutosta sekä semanttisia ja sanastollisia verkkoja. Tuloksena itse analyysin tuloksien lisäksi on analyysiprotokolla, jolla pystytään analysoimaan suomenkielisiä tekstejä. Fysiikan aineenopettajaopiskelijoiden tekstien analyysistä saatiin selville, että aineenopettajaopiskelijoiden sanaston käyttö on varsin laajaa ja monipuolista. Analyysin perusteella saatiin myös selville teksteissä esiintyviä mm. tekstissä esiintyviä lauseenrakenteita ja että teksteissä fysiikan aineenopettajaopiskelijat vaihtoivat aihetta melkein joka toisessa virkkeessä. Analyysiprotokollaa pystytään kuitenkin vielä jatkossa tarkentamalla ja selventämällä sitä. Analyysiprotokollan luotettavuutta pitäisi myös tutkia siten, että toinen analyysin tekijä suorittaisi analyysin.
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(2020)Tässä työssä on tavoitteena esittää yksi opetuksellinen malli sille, miten fysiikkaa voidaan opettaa huvipuistokontekstissa lukiotasolla. Työssä selvitettiin, millaisia fysiikan ilmiöitä huvipuistossa voidaan havaita, miten huvipuistolaitteita voidaan hyödyntää lukion fysiikan kokeiden tekemisessä ja miten huvipuistovierailua voidaan hyödyntää lukion fysiikan opetuksessa. Työn teoriaosuudessa tarkastellaan kiinnostuksen kehittymistä, johon opettaja voi vaikuttaa valitsemillaan sisällöillä, konteksteilla ja opetustavoilla. Koulun ulkopuolella tapahtuvalla oppimisella voi olla vaikutusta kiinnostukseen ja oppimiseen, ja huvipuisto voi tarjota tällaisen kiinnostusta lisäävän kontekstin. Lisäksi tarkastellaan huvipuistolaitteisiin liittyviä fysiikan ilmiöitä: dynamiikkaa, energiamuutoksia ja sähkömagnetismia. Työssä esitellään erilaisia mittausvälineitä ja älypuhelinsovelluksia, joita huvipuistossa tehtävissä mittauksissa voidaan käyttää, ja niihin liittyviä suureita. Lisäksi esitellään Linnanmäen huvipuistossa mahdollisia mittauksia. Työssä toteutettiin empiirinen tutkimus Linnanmäen huvipuistossa opiskelijaryhmän kanssa. Kolmiosainen vierailu toteutettiin yhteistyössä pääkaupunkiseudulla sijaitsevan lukion kanssa ja siihen sisältyi harjoittelu- ja analysointiosuudet koululla sekä mittausosuus Linnanmäellä. Mittauksissa käytettiin Vernierin LabQuest 2 -laitteistoa. Seuraavissa tutkimuksissa voitaisiin selvittää, missä määrin huvipuistokonteksti lisää kiinnostusta fysiikkaan ja onko huvipuistovierailulla vaikutusta fysiikan oppimiseen.
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(2020)Predicting patient deterioration in an Intensive Care Unit (ICU) effectively is a critical health care task serving patient health and resource allocation. At times, the task may be highly complex for a physician, yet high-stakes and time-critical decisions need to be made based on it. In this work, we investigate the ability of a set of machine learning models to algorithimically predict future occurrence of in hospital death based on Electronic Health Record (EHR) data of ICU-patients. For one, we will assess the generalizability of the models. We do this by evaluating the models on hospitals the data of which has not been considered when training the models. For another, we consider the case in which we have access to some EHR data for the patients treated at a hospital of interest. In this setting, we assess how EHR data from other hospitals can be used in the optimal way to improve the prediction accuracy. This study is important for the deployment and integration of such predictive models in practice, e.g., for real-time algorithmic deterioration prediction for clinical decision support. In order to address these questions, we use the eICU collaborative research database, which is a database containing EHRs of patients treated at a heterogeneous collection of hospitals in the United States. In this work, we use the patient demographics, vital signs and Glasgow coma score as the predictors. We devise and describe three computational experiments to test the generalization in different ways. The used models are the random forest, gradient boosted trees and long short-term memory network. In our first experiment concerning the generalization, we show that, with the chosen limited set of predictors, the models generalize reasonably across hospitals but that only a small data mismatch is observed. Moreover, with this setting, our second experiment shows that the model performance does not significantly improve when increasing the heterogeneity of the training set. Given these observations, our third experiment shows that
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(2019)Oppilaiden kiinnostus matematiikkaa kohtaan on tutkimusten mukaan laskussa. Samalla oppilaiden matematiikan osaamisen taso on heikentynyt. Matematiikan opettajien laadukkaalla koulutuksella pyritään vastaamaan opiskelijoiden heikentyneeseen matematiikan osaamiseen ja kiinnostukseen. Yksi keino lisätä matematiikan kiinnostavuutta, on kehittää matematiikan opettajien koulutusta relevantimmaksi opiskelijoiden näkökulmasta. Lisäksi tietotekniikan, kuten GeoGebran käytöllä opetuksessa on tärkeä rooli oppilaiden matematiikan kiinnostuksen lisäämisessä. Tässä tutkimuksessa tutkitaan matematiikan opettajille järjestettyä LUMA-keskuksen GeoGebra opetuksessa -verkkokoulutusta. Tutkimuksen teoriaosuudessa tarkastellaan GeoGebran käyttöä matematiikan opetuksessa, matematiikan opettajankoulutusta ja verkkokoulutusta sekä sen relevanssia. Tutkimuksen kohteena oli GeoGebra opetuksessa -verkkokoulutuksen suorittaneet opiskelijat (N=30). Opiskelijat olivat lukion, yläkoulun ja alakoulun opettajia sekä aineenopettajaopiskelijoita. Koulutus järjestettiin syksyllä 2018. Tutkimuksen tavoitteena oli selvittää, kuinka merkityksellinen koulutus oli opiskelijoille Stuckey et al. (2013) luoman relevanssiteorian mukaisilla relevanssin eri tasoilla. Tutkimuksessa tarkasteltiin myös sukupuolen vaikutusta opiskelijoiden näkemyksiin. Lisäksi tutkittiin mitä odotuksia opiskelijoilla oli koulutuksesta ja vastasitko koulutus niitä. Tutkimusmenetelmänä käytettiin kyselylomaketutkimusta. Kyselylomakkeen strukturoidut kysymykset analysoitiin sekä laadullisena että määrällisenä aineistona ja avoimet kysymykset analysoitiin sisällönanalyysin avulla. Tutkimuksen luotettavuutta tarkasteltiin realibiliteetin ja validiteetin avulla. Tutkimustulokset osoittavat, että GeoGebra opetuksessa -verkkokoulutus oli opiskelijoiden näkökulmasta relevanttia henkilökohtaisen ja ammatillisen relevanssin tasoilla yhteiskunnallisen tason jäädessä vähemmälle. Koulutuksen todettiin vastaavan vahvasti opiskelijoiden odotuksia koulutukselta. Opiskelijat kokivat koulutuksen erittäin hyödyllisenä oman työn kannalta. Tämä tutkimus antaa tietoa matematiikan opettajien verkkokoulutuksesta. Tutkimuksen tuloksia voidaan hyödyntää erityisesti GeoGebra opetuksessa -koulutuksen kehittämisessä ja jatkotutkimuksessa.
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(2020)The Sukseton area is located in the northern part of Kittilä municipality, Central Lapland Greenstone Belt, approximately 15 km N from Suurikuusikko gold mine and 5 km NW from Iso-Kuotko orogenic gold deposit, between several large crustal scale thrust and shear zones. This area is a mix of different volcanic formations of Kittilä suite, felsic intrusion of Vuotso Complex and Paleoproterozoic intrusive rocks in the north. In addition to this, several porphyry dykes cut the Kittilä suite volcanic rocks around the area. Exploration work in this area started in the 1980’s when Outokumpu Oy found two minor gold and gold-copper mineralizations. In 2017, Agnico Eagle Finland Oy continued exploration in this area, intending to define the regional geology and the extent of the mineralizations. As a result of this exploration work, this study investigates more closely the regional geology, geochemistry, metamorphism and structural geology of the Sukseton area, as well as the geochronology of associated porphyry dykes. To understand and define the geology of the area, the following methods were used: geological bedrock and exploration trench mapping, interpretation of drill core loggings and several geophysical surveys, optical studies of polished thin sections and U–Pb dating a porphyry dyke sample. The metamorphic conditions of the area were studied through thorough petrological studies. In addition, an extensive geochemical and geotectonic classification of the rocks in the area was conducted. The Sukseton area composes mainly of different tholeiitic basalts and pyroclastic rocks with minor sulphide rich graphitic volcanic sediment and chert sections. Based on this study, these volcanic rocks originate from island arcs and mid-ocean ridges. With the help of geophysical surveys and field measurements, a couple of large fold structures were identified from the eastern part of the study area as well as a large shear zone in the middle of the area striking NE–SW. Porphyry dykes cut the volcanic rocks all around the area giving the minimum age of 1940±18 Ma for the volcanic rocks. Composition of porphyry dykes vary from rhyolites to basalt and they have similar geochemical characteristics with Nyssäkoski type felsic veins. The peak metamorphic conditions in the area represent high-P amphibolite facies metamorphism. Also, hydrothermal alteration is common in Sukseton and it can be metamorphic and magmatic in origin.
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(2019)This study consists of a comprehensive characterization of the geology, geochemistry, alteration, and mineralization at the Ronaldo prospect as well as an evaluation of its ore potential. Previous mapping campaigns of the prospect, which lies in the Central Andes in Peru at an elevation of 4300 metres, have identified intrusions overlain by a volcanic package. The intrusions are crosscut by silicified ridges that host epithermal mineralization. Satellite imagery reveals that the topographically elevated areas exhibit strongly altered rocks identified as an advanced argillic-altered lithocap. The methods used to define and better understand the geology and the evolution of the hydrothermal system included reconnaissance field mapping, whole-rock geochemistry, short-wave infrared spectroscopy, petrography, and geochronology. Previous studies have shown that only high-sulfidation epithermal mineralization can be spatially and temporally linked to porphyry Cu mineralization, and therefore this study investigates – among other aspects – what type of epithermal mineralization is present at Ronaldo in order to evaluate the potential for concealed at-depth porphyry Cu mineralization. Two separate lower Miocene intrusive units were identified, a porphyritic diorite and a porphyritic granodiorite, whose average age difference is 1.79 Ma. The intrusive units display intermediate argillic alteration. The overlying extrusive units are Sacsaquero Formation basaltic andesites and ignimbrites that are either unaltered or display propylitic alteration. The basaltic andesite roof pendants observed at Ronaldo indicate that the tops of the intrusions are preserved. At high elevations, advanced argillic alteration composed of pyrophyllite, kaolinite, and dumortierite was observed. This area is the remnant, deeper zone of a larger lithocap. The steeply dipping silicified ridges that display sericitic alteration were inferred to be the root zone of this lithocap. Elevated values of trace elements such as Te, Bi, As, and Sb suggest that the Ronaldo prospect is mostly situated in a sericitic alteration zone related to a porphyry-like magmatic-hydrothermal source located at greater depth. Isolated magnetite aggregates were observed in magmatic-hydrothermal breccia, which indicates that the sericitic alteration may have overprinted potassic alteration. A few intermediate-sulfidation epithermal veins and porphyry-related veins, including a banded molybdenite quartz vein, were observed in the creek near the major fault. At Ronaldo, high silica content and sericitic alteration correlate well with elevated concentrations of Ag, Au, and Mo, whereas Cu concentration does not correlate well with any alteration type or with silica content. Quartz veinlets in the silicified ridges that host abundant Ag and Au mineralization were interpreted to have formed at a slightly later stage and to be unrelated to the magmatic-hydrothermal system. This mineralization was interpreted to be low-sulfidation epithermal in origin due to features such as abundant adularia, lattice-textured bladed calcite replaced by quartz, crustiform banding, banded quartz-chalcedony veins, druse-lined cavities, and high Ag/Au ratios. In conclusion, the Ronaldo prospect comprises a hydrothermal system in which the deep, root zone of an advanced argillic lithocap is exposed. The exploration potential for low-sulfidation epithermal mineralization in the silicified ridges is rather significant, whereas the potential for porphyry Cu mineralization is minor due to the lack of appreciable Cu and Mo mineralization, typically shallow-depth porphyry-related hydrothermal alteration, and the lack of high-sulfidation epithermal mineralization.
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(2020)This thesis provides a proof and some applications for the famous result in topology called the Borsuk-Ulam theorem. The standard formulation of the Borsuk-Ulam theorem states that for every continuous map from an n-sphere to n-dimensional Euclidean space there are antipodal points that map on top of each other. Even though the claim is quite elementary, the Borsuk-Ulam theorem is surprisingly difficult to prove. There are many different kinds of proofs to the Borsuk-Ulam theorem and nowadays the standard method of proof uses heavy algebraic topology. In this thesis a more elementary, geometric proof is presented. Some fairly fundamental geometric objects are presented at the start. The basics of affine and convex sets, simplices and simplicial complexes are introduced. After that we construct a specific simplicial complex and present a method, iterated barycentric subdivision, to make it finer. In addition to simplicial complexes, the theory we are using revolves around general positioning and perturbations. Both of these subjects are covered briefly. A major part in our proof of the Borsuk-Ulam theorem is to show that a certain homotopy function F from a specific n + 1-manifold to the n-dimensional Euclidean space can be by approximated another map G. Moreover this approximation can be done in a way so that the kernel of G is a symmetric 1-manifold. The foundation for approximating F is laid with iterated barycentric subdivision. The approximation function G is obtained by perturbating F on the vertices of the simplicial complex and by extending it locally affinely. The perturbation is done in a way so that the image of vertices is in a general position. After proving the Borsuk-Ulam theorem, we present a few applications of it. These examples show quite nicely how versatile the Borsuk-Ulam theorem is. We prove two formulations of the Ham Sandwich theorem. We also deduce the Lusternik-Schnirelmann theorem from the Borsuk- Ulam theorem and with that we calculate the chromatic numbers of the Kneser graphs. The final application we prove is the Topological Radon theorem.
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(2020)K-mer counting is the process of building a histogram of all substrings of length k for an input string S. The problem itself is quite simple, but counting k-mers efficiently for a very large input string is a difficult task that has been researched extensively. In recent years the performance of k-mer counting algorithms have improved significantly, and there have been efforts to use graphics processing units (GPUs) in k-mer counting. The goal for this thesis was to design, implement and benchmark a GPU accelerated k-mer counting algorithm SNCGPU. The results showed that SNCGPU compares reasonably well to the Gerbil k-mer counting algorithm on a mid-range desktop computer, but does not utilize the resources of a high-end computing platform as efficiently. The implementation of SNCGPU is available as open-source software.
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(2020)Due to the unique properties of foams, they can be found in many different applications in a wide variety of fields. The study of foams is also useful for the many properties they share with other phenomena, like impurities in cooling metals, where the impurities coarsen similarly to bubbles in foams. For these and other reasons foams have been studied extensively for over a hundred years and continue being an interesting area of study today due to new insights in both experimental and theoretical work and new applications waiting to be used and realized in different industries. The most impactful early work in the study of the properties of foams was done in the late 1800s by Plateau. His work was extended in the early to mid-1900s by Lifshitz, Slyozov, Wagner and von Neumann and by many more authors in recent years. The early work was mostly experimental or theoretical in the sense of performing mathematical calculations on paper, while the modern methods of study have kept the experimental part -- with more refined methods of measurement of course -- but shifted towards the implementation of the theory as simulations instead of solving problems on paper. In the early 90s Durian proposed a new method for simulating the mechanics of wet foams, based on repulsive spring-like forces between neighboring bubbles. This model was later extended to allow for the coarsening of the foam, and a slightly changed version of this model has been implemented in the code presented in this thesis. As foams consist of a very large number of bubbles, it is important to be able to simulate sufficiently large systems to realistically study the physics of foams. Very large systems have traditionally been too slow to simulate on the individual bubble level in the past, but thanks to the popularity of computer games and the continuous demand for better graphics in games, the graphics processing units have become very powerful and can nowadays be used to do highly parallel general computing. In this thesis, a modified version of Durian's wet foam model that runs on the GPU is presented. The code has been implemented in modern C++ using Nvidia's CUDA on the GPU. Using this program first a typical two-dimensional foam is simulated with 100000 bubbles. It is found that the simulation code replicates the expected behaviour for this kind of foam. After this, a more detailed analysis is done of a novel phenomenon of the separation of liquid and gas phases in low gas fraction foams that arises only with sufficiently large system sizes. It is found that the phase separation causes the foam to evolve as would a foam of higher gas fraction until the phases have mixed back together. It is hypothesized that the reason causing the phase separation is related to uneven energy distribution in the foam, which itself is related to jamming and uneven distribution of the sizes of the bubbles in the foam.
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(2020)Visualization is an indispensable method in the exploration of genomic data. However, the current state of the art in genome browsers – a class of interactive visualization tools – limit the exploration by coupling the visual representations with specific file formats. Because the tools do not support the exploration of the visualization design space, they are difficult to adapt to atypical data. Moreover, although the tools provide interactivity, the implementations are often rudimentary, encumbering the exploration of the data. This thesis introduces GenomeSpy, an interactive genome visualization tool that improves upon the current state of the art by providing better support for exploration. The tool uses a visualization grammar that allows for implementing novel visualization designs, which can display the underlying data more effectively. Moreover, the tool implements GPU-accelerated interactions that better support navigation in the genomic space. For instance, smoothly animated transitions between loci or sample sets improve the perception of causality and help the users stay in the flow of exploration. The expressivity of the visualization grammar and the benefit of fluid interactions are validated with two case studies. The case studies demonstrate visualization of high-grade serous ovarian cancer data at different analysis phases. First, GenomeSpy is being used to create a tool for scrutinizing raw copy-number variation data along with segmentation results. Second, the segmentations along with point mutations are used in a GenomeSpy-based multi-sample visualization that allows for exploring and comparing both multiple data dimensions and samples at the same time. Although the focus has been on cancer research, the tool could be applied to other domains as well.
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