Browsing by Title
Now showing items 4630-4649 of 33008
-
(2017)The physiological effects of drought on trees has been studied excessively but many of them remain unclear. In this thesis I studied tree sugar dynamics under drying-wetting cycle as well as the role of soil hydraulic conductivity on how trees experience drought. I experimented with five Norway spruce seedlings in October and November 2016. The seedlings were in water after which they were put in to PEG solution of -0.5 MPa for 24 h and then transferred back to water. Sugar samples were taken from liquids, needles and roots once for every phase. Osmolality samples were taken from current year needles and water potential samples were taken from current year needles and roots every half an hour during day time. Continuous gas exchange measurements were done with Walz GFS-3000. There was no change in osmolality and no significant change in photosynthesis or transpiration rate. For sugar concentrations there was significant increase of non-structural carbohydrates in needles and significant decrease in roots. There was no change in sugar concentration in liquid. Overall impression was that trees did not suffer much from the PEG treatment. The results supported my hypothesis that changes in soil hydraulic conductivity are more important to effects of drought than changes in soil water potential.
-
(2021)Phase transitions in the early Universe and in condensed matter physics are active fields of research. During these transitions, objects such as topological solitons and defects are produced by the breaking of symmetry. Studying such objects more thoroughly could shed light on some of the modern problems in cosmology such as baryogenesis and explain many aspects in materials research. One example of such topological solitons are the (1+1) dimensional kinks and their respective higher dimensional domain walls. The dynamics of kink collisions are complicated and very sensitive to initial conditions. Making accurate predictions within such a system has proven to be difficult, and research has been conducted since the 70s. Especially difficult is predicting the location of resonance windows and giving a proper theoretical explanation for such a structure. Deeper understanding of these objects is interesting in its own right but can also bring insight in predicting their possibly generated cosmological signatures. In this thesis we have summarized the common field theoretic tools and methods for the analytic treatment of kinks. Homotopy theory and its applications are also covered in the context of classifying topological solitons and defects. We present our numerical simulation scheme and results on kink-antikink and kink-impurity collisions in the $\phi^4$ model. Kink-antikink pair production from a wobbling kink is also studied, in which case we found that the separation velocity of the produced kink-antikink pair is directly correlated with the excitation amplitude of the wobbling kink. Direct annihilation of the produced pair was also observed. We modify the $\phi^4$ model by adding a small linear term $\delta \phi^3$, which modifies the kinks into accelerating bubble walls. The collision dynamics and pair production of these objects are explored with the same simulation methods. We observe multiple new effects in kink-antikink collisions, such as potentially perpetual bouncing and faster bion formation in comparison to the $\phi^4$ model. We also showed that the $\delta$ term defines the preferred vacuum by inevitably annihilating any kink-antikink pair. During pair production we noticed a momentum transfer between the produced bion and the original kink and that direct annihilation seems unlikely in such processes. For wobbling kink - impurity collisions we found an asymmetric spectral wall. Future research prospects and potential expansions for our analysis are also discussed.
-
(2021)Post-transcriptional modifications (PTMs) in RNA are present in all known RNA species and conserved in all kingdoms of life. Transfer RNA (tRNA) has been shown to have numerous conserved modifications, which exemplifies the importance of modifications having impact on the structure of the tRNA and its function as carrier of the amino acids. Ribosomal RNAs (rRNA) are universally modified as well, and modifications are situated at functionally important spots of the ribosome. Given the fact that types and sites of modifications are conserved, it is likely that these modifications have been selected for and that they optimize the ribosomal structure and functions. Stress, such as temperature or infection by a pathogen, is known to change the presence or abundance of modifications in RNA molecules and thereby affect translation efficacy. In line with that, this master’s thesis project sought to gain insight into the dynamics of PTMs in tRNA and rRNA upon oxidative stress, with the goal of utilizing recently optimized UPLC/MS method for identifying modified ribonucleosides. As the specific aim of the thesis was to estimate the change in PTMs in tRNA and rRNA in response to oxidative stress with 0.5 mM and 2 mM hydrogen peroxide H2O2, 3 immediate goals were: (i) to isolate total tRNA from yeast grown in stress conditions, (ii) to isolate rRNA from yeast 80S ribosomes, and (iii) to identify present modifications using mass spectrometry. Yeast was cultured in presence of H2O2 as a stressor in mentioned concentrations, and both treatments considered showed a difference in survival when compared to the control. Rough cell concentration estimates (OD600) did not show the effect of the stressor on cell survival clearly, but when number of viable cells per mL was estimated, it was clear that growth of the stressed yeast cultures was hindered 2 hours after exposure to H2O2 but recovered during the 24 hours. Firstly, using UPLC/MS analysis, 29 modifications were identified in tRNA from control and H2O2 treated yeast. Most identified modifications showed no change in abundance in treatments, which is to be verified with additional replicates. However, distinct dynamics of stress-related change was found for several modifications, revealing additional modifications that may play a role in stress related modificome reprogramming to the previously known signature modifications of oxidative stress. It was expected that recovery of culture growth after 24 hours may be accompanied with modification level recovery. However, that was not demonstrated here as downregulation at 2 hours followed by upregulation at 24 hours was seen for 2-methylthio-N6-methyladenosine, N4-acetylcytidine and 5-methoxycarbonylmethyl-2-thiouridine, and the reverse was shown for N4-methylcytidine. Upregulation in both time points was also shown here for some modifications. Taken together, these results confirm a complex and dynamic control of tRNA modifications in cellular survival responses. Modifications found to be affected by oxidative stress are most frequently located on the wobble position 34 and anticodon loop position 37, so it is expected that changes in their modification levels could directly affect the tRNA function in translation, making them a specific target for future research. Secondly, modifications in rRNA from control yeast cultures were identified, such as expected methylations of all 4 canonical nucleosides. However, further analysis will be needed to confirm the other identified modifications, due to the potential mRNA and tRNA contamination. Optimizing the method for rRNA modifications identifications by acquiring more modified nucleosides specific for the rRNA to use as standards in the analysis, analyzing rRNA types separately and using tandem mass spectrometry would enable getting a deeper understanding of which modifications are present and where they are positioned. Finally, it would enable reliable identification of the signals of novel modifications present in rRNA, such as the tRNA modification 5-carbamoylmethyluridine signal found here. In conclusion, this thesis work lays the foundation to study the evolutionary conserved function of PTM changes during stress as modulators of translation, using the methodological approaches discussed in-depth within the thesis, primarily to confirm the intriguing results found here.
-
(2020)Context. Software Product Line (SPL) is a set of software system products that have common features and product-specific features. Dynamic Software Product Line (DSPL) is an SPL that features runtime variability. Objective. The main objective of this study is to evaluate the latest research related to SPL dynamic variability in general. The second objective of this study is to investigate dynamic variability modeling methods and tools that are utilized and introduced for SPLs by the scholars. The third objective of this study is to investigate testing methods and tools that are utilized and introduced for DSPLs by the scholars. Method. The scientific research method of this study is Systematic Literature Review (SLR). Papers included are published between years 2015 and 2017. Four scientific digital libraries were used as data sources for the papers. Results. The main result of this study is that between years 2015 and 2017, there has been an active research community studying SPL dynamic variability. For all 25 papers included in this study, on a scale of 0 to 10, the arithmetic mean of the quality scores is 7.14 (median is 7.5). One industrial practice DSPL implementation case study was presented by the scholars. Three other case studies seemed to be more or less simplified exemplar of industry practice DSPL implementations. Two studies were focusing in testing aspects of DSPLs. The second result of this study is that scholars have utilized 19 existing dynamic variability modeling methods for SPLs, and introduced 17 new dynamic variability modeling methods for SPLs. Scholars have utilized seven existing dynamic variability modeling tools for SPLs, and introduced four new dynamic variability modeling tools for SPLs. The third result of this study is that scholars have introduced four new testing methods for DSPLs, and utilized two existing testing tools for DSPLs. Conclusions. The general conclusion of this study is that albeit SPL dynamic variability has been actively studied between years 2015 and 2017, there are still open research areas, especially in the field of industry practice use and testing of DSPLs. 2012 ACM Computing Classification System (CCS): Software and its engineering -> Software creation and management -> Software development techniques -> Reusability -> Software product lines Software and its engineering -> Software creation and management -> Designing software -> Software design engineering
-
(2015)In this thesis we consider dynamic X-ray computed tomography (CT) for a two dimensional case. In X-ray CT we take X-ray projection images from many different directions and compute a reconstruction from those measurements. Sometimes the change over time in the imaged object needs to be taken into account, for example in cardiac imaging or in angiography. This is why we're looking at the dynamic (something changing in time, while taking the measurements) case. At the beginning of the thesis in chapter 2 we present some necessary theory on the subject. We first go through some general theory about inverse problems and the concentrate on X-ray CT. We talk about ill-posedness of inverse problems, regularization and the measurement proses in CT. Different measurement settings and the discretization of the continuous case are introduced. In chapter 3 we introduce a solution method for the problem: total variation regularization with Barzilai-Borwein minimization method. The Barzilai-Borwein minimization method is an iterative method and well suited for large scale problems. We also explain two different methods, the multi-resolution parameter choice method and the S-curve method, for choosing the regularization parameter needed in the minimization process. The 4th chapter shows the materials used in the thesis. We have both simulated and real measured data. The simulated data was created using a rendering software and for the real data we took X-ray projection images of a Lego robot. The results of the tests done on the data are shown in chapter 5. We did tests on both the simulated and the measured data with two di erent measurement settings. First assuming we have 9 xed source-detector pairs and then that we only one source-detector pair. For the case where we have only one pair, we tested the implemented regularization method we begin by considering the change in the imaged object to be periodic. Then we assume can only use some number of consecutive moments, based on the rate the object is chancing, to collect the data. Here we only get one X-ray projection image at each moment and we combine measurements from multiple di erent moments. In the last chapter, chapter 6, we discuss the results. We noticed that the regularization method is quite slow, at least partly because of the functions used in the implementation. The results obtained were quite good, especially for the simulated data. The simulated data had less details than the measured data, so it makes sense that we got better results with less data. Already with only four angles, we cold some details with the simulated data, and for the measured data with 8 angles and with 16 angles details were also visible in the case of measured data.
-
(2015)Introduction. Previous studies suggest that dyslexic pupils have inordinate difficulties learning foreign languages at school. The present study examined the mismatch negativity (MMN) brain responses elicited by foreign language words and nonwords in dyslexic children compared to typically reading controls. MMN reflects early processing stages in auditory cortex. The aim of this study was to determine whether dyslexic pupils have impaired MMNs for foreign language words or speech stimuli in general, and whether word familiarity has a different effect on the two groups. In addition, the correlations between MMN differences and reading and cognitive skills were analysed. Methods. Participant groups consisted of 14 dyslexic school children, and 14 typically reading controls. Before brain recordings, literacy skills and cognitive functioning were tested. Brain responses to English words (she, shy) and nonwords (shoy), and Finnish words (sai, soi) and nonwords (sii) were measured with electroencephalography (EEG). Results and conclusions. The results suggested that compared to controls, dyslexic children's MMN responses to foreign language were impaired for a familiar word she, but only. However, the groups did not differ in processing speech-sounds in general. In addition, weak MMN responses to the foreign word were associated with poorer reading skills and slower rapid naming in mother language. The results of this study suggest that the establishment, access and activation of memory representations for foreign words is impaired in dyslexia. In addition, the finding that poor performance in native language reading is correlated with the strength of brain responses to foreign language suggests that there are common factors underlying literacy skills and foreign language learning.
-
(2020)Objective of the study. This Master’s thesis investigates dyslexic university students and their learning experiences. Previous research has shown that dyslexia is related to learning in a variety of ways. However, previous research is primarily focused on children and adoles-cents. Further academic studies set new types of requirements to learning. Thus, it is neces-sary to explore dyslexic university students in order to find out especially the factors that are impeding and enhancing their studies. Efficient progress and the completion of academic studies are important for the students themselves, but also for the university and the society. This research examines the obstacles that dyslexic students face during their studies, and the variety of means and practices they use to overcome these challenges. Methods. The research material consists of ten semi-structured theme interviews. In the in-terviews the students were asked about their study habits, how dyslexia appears in their studies, which impeding and enhancing factors they could name, and what kind of social support they have received during the studies. The interview data were analysed by using a qualitative abductive content analysis. Finally, four different student profiles were formed based on the analysis. Results and conclusions. Results of the study indicated, that the dyslexic students experi-ence various impeding and enhancing factors in their academic studies. In addition to the factors related directly to dyslexia, study exhaustion was named as a major impeding factor. Self-regulation skills, study engagement, and social support were considered to be the most central factors in overcoming those challenges. Student profiles provide direction for differ-ent measures of support. According to the results, the interventions that are most crucially needed relate to the development of self-regulation skills during the studies, and to recogniz-ing and reducing study exhaustion at their early stages.
-
(2021)Tämän tutkimuksen tavoitteena oli kartoittaa kieltenopettajien kokemuksia lukivaikeuteen liittyen opetustyön näkökulmasta. Tarve tutkimukselle syntyi siltä pohjalta, että lukivaikeuden yleisyydestä huolimatta sitä käsiteltiin aineenopettajakoulutuksessa kokemukseni perusteella erittäin vähän ja todella pintapuolisesti. Aiempi tutkimus osoittaa, että lukivaikeuden taustalla on usein fonologisen tietoisuuden ja työmuistin heikkoutta, mikä luo omat haasteensa niin ensikielen kuin vieraiden kielten oppimiselle ja opiskelulle. Tässä tutkimuksessa selvitetään suomalaisten kieltenopettajien kokemuksia heidän koulutuksesta, resursseista ja kyvyistään huomioida lukivaikeutta päivittäisessä opetustyössä. Lisäksi selvitetään millaisia konkreettisia keinoja ja toimintatapoja kieltenopettajat ovat havainneet toimiviksi päivittäisessä opetustyössään ja lukivaikeuden kanssa kamppailevia oppilaita ja opiskelijoita kohdatessaan. Tutkimus toteutettiin kyselytutkimuksena ja materiaalin keräämiseen käytettiin verkkopohjaista kyselylomaketta. Vastauksia lomakkeeseen kertyi kuuden viikon aikana syystalvella 2020 yhteensä 128 kappaletta. Tilastoinnin ja saatujen tilastojen vertailun ohella käytettiin myös tekstianalyysin keinoja avointen vastausten tutkimisessa sekä kategorisoinnissa. Tutkimus osoitti, että suomalaiset kieltenopettajat ovat saaneet hyvin vähän tai ei lainkaan koulutusta lukivaikeuteen liittyen opettajankoulutuksensa aikana. Lisäksi vain noin puolet vastaajista ilmoittaa saaneensa jonkinlaista täydennyskoulutusta aiheesta. Täydennyskoulutuksen laajuus ja sisällöt kuitenkin vaihtelee paljolti. Yli puolet vastaajista myös kokee, ettei heillä ole riittävästi aikaa tai he eivät tiedä sopivista keinoista ja työtavoista, joita voisi hyödyntää päivittäisessä opetustyössä lukivaikeuden aiheuttamien haasteiden lievittämiseksi. Vastaajat olivat kuitenkin havainneet muun muassa eriyttämisen keinot, suullisen työskentelyn painottamisen sekä lisäajan antamisen varsin toimiviksi. Näiden lisäksi mainittiin myös erilaiset visuaalisesti kokonaisuuksia havainnollistavat ja tekstejä selkeyttävät menettelyt ja tukitoimet, olennaisimpien oppiainesten korostaminen sekä positiivisen ja kannustavan palautteen merkitys. Näitä opettajien hyväksi havaitsemia keinoja tukee myös aiempi kirjallisuus ja tutkimus aiheesta.
-
(2016)Background Constipation and dyspepsia are disturbing gastrointestinal symptoms that are often ignored in research on physical comorbidities of schizophrenia. Aims Our aim was to assess dyspepsia and constipation in a sample of outpatients with schizophrenia spectrum psychoses. Methods A general practitioner performed a thorough physical health check for 275 outpatients and diagnosed constipation and dyspepsia. We assessed the possible contribution of several sociodemographic, lifestyle, and clinical variables to constipation and dyspepsia using logistic regression analysis. We also assessed whether these symptoms were associated with abnormal laboratory findings. Results The prevalence of constipation was 31.3%, and of dyspepsia 23.6%. Paracetamol (OR=3.07, 95% CI 1.34–7.02) and clozapine use (OR=5.48, 95% CI 2.75–10.90), older age (OR=1.04, 95% CI 1.01–1.06), and living in sheltered housing (OR=2.49, 95% CI 1.16–5.33) were risk factors for constipation. For dyspepsia the risk factors were female sex (OR=2.10, 95% CI 1.15–3.83), non-steroidal anti-inflammatory drugs (OR=2.47, 95% CI 1.13–5.39), and diabetes medication (OR=2.42, 95% CI 1.12–5.25). Patients with dyspepsia had lower hemoglobin and hematocrit and higher glucose values than those without dyspepsia. Patients with constipation had lower thrombocyte values than patients without constipation. However, these findings were explained by factors predisposing to constipation and dyspepsia. Conclusions Clozapine use markedly increases the risk of constipation and may lead to life-threatening complications. In addition, analgesics and diabetes medication were related to gastrointestinal symptoms. These medications and their association to gastrointestinal symptoms should be kept in mind when treating patients with schizophrenia.
-
(2019)Pro gradu – tutkielmani kohdeteos on Viktor Martinovitšin romaani Paranoia (2009/2013; suom. Anna Taitto). Teos kuvaa dystopiayhteiskuntaa, jossa dystopiagenren tradition mukaisesti yksilön intressit joutuvat konfliktiin diktatorisen vallankäyttäjän ja dystooppisen valtiojärjestelmän kanssa. Esitän tutkielmassani, että romaanista löytyy karnevalistisia piirteitä, kuten karnevaalitorin piirteitä, torikielen ominaisuuksien käyttöä sekä karnevaalikuninkaan aihe. Osoitan, miten mainitut karnevalismin käsitteet tulevat ilmi tietyissä, romaanin kuvaamaan yhteiskuntaan, sen poliittiseen järjestelmään ja valtarakenteisiin kytkeytyvissä tapahtumissa, kohtauksissa, lausumissa ja henkilösuhteissa. Karnevalistinen, hierarkkisia valtasuhteita purkava pyrkimys ei kuitenkaan realisoidu elvyttäväksi uudistumiseksi. Karnevalistisuus suhteutuu Paranoian kuvaaman yhteiskunnan dystopiapiirteiden, kuten hierarkkisten voimasuhteiden epätasapainon ja valtiollisen, yksilöitä kontrolloivan valvonta- ja väkivaltakoneiston, kanssa siten, että karnevalistiset elementit eivät kasva täyteen mittaansa, vaan ne mitätöityvät, tuhoutuvat tai tulevat sensuroiduiksi. Poikkeuksena tästä on karnevaalikuninkaan aihe, jonka tunnusmerkit täyttyvät muita karnevalistisia elementtejä täydemmin. Romaanin päähenkilön voi tulkita todellisen hallitsijan paikalle väliaikaisesti pääseväksi karnevaalikuninkaaksi, joka on samalla epävirallista totuutta julistava narri, todellisen kuninkaan antipodi sekä väkivaltaisen kohtalon kokeva syntipukki. Diktatorisen hallitsijan asemaa koettelevana hahmona hän soveltuu myös dystopiagenrelle tyypillisen tuhoutuvan sankarin ja syntipukin malliin. Teoreettisena taustana ja vertailun työkaluna käytän Mihail Bahtinin karnevalismin teoriaa sekä Bahtinin karnevaaliteoriaan pohjautuvaa, jälkimodernin ajan kirjallisuuteen kohdentuvaa David K. Danowin sovellusta karnevalistisuudesta. Analysointimenetelmänä käytän erityisesti vertailua bahtinilaisen karnevaalin piirteiden ja Paranoiassa esiintyvien karnevalististen piirteiden yhtäläisyyksien ja eroavaisuuksien välillä. Teoksen dystopiapiirteiden luokittelussa tukeudun Erica Gottliebin tutkimukseen dystopioista, minkä perusteella suhteutan Paranoian karnevalistisia piirteitä siinä kuvatun dystooppisen valtiojärjestelmän kehykseen.
-
(2023)Tämän kirjallisuuskatsauksen tavoitteena on kuvata dystrofiinin rooli ja merkitys lihaksen normaalissa toiminnassa, koota yhteen nykytietämys Duchennen lihasdystrofian patofysiologiasta sekä käydä läpi sairauden tutkimuksissa yleisimmin käytettäviä eläinmalleja. Duchennen lihasdystrofia on vakava, etenevä, perinnöllinen lihasrappeumasairaus, joka johtaa lihasheikkouteen, liikkumisen vaikeutumiseen, pyörätuolista riippuvuuteen, avustettuun hengitykseen ja lopulta ennenaikaiseen kuolemaan. Sairaus on poikalapsien yleisin neuromuskulaarinen sairaus, johon sairastuu noin 1/5000 syntyvästä poikalapsesta. Sairaus johtuu X-kromosomissa sijaitsevan dystrofiinigeenin mutaatioista, jonka seurauksena ei synny toimivaa dystrofiiniproteiinia. Ihmisten lisäksi homologiset sairaudet esiintyvät koiralla, hiirellä sekä kissalla. Dystrofiini ilmenee luusto- ja sydänlihaskudoksissa sekä pieninä määrinä aivoissa ja muualla kehossa. Lihassyissä dystrofiini sijaitsee lihassolukalvon alla, jossa se yhdistää solun tukirangan lihassolukalvoon sekä sitä ympäröivään tyvikalvoon. Dystrofiini muodostaa yhdessä muiden proteiinien kanssa dystrofiini-glykoproteiinikompleksin, joka toimii useissa tehtävissä solujen signaloinnissa sekä lihassolukalvon eheyden ylläpidossa lihassupistusten aikana. Ilman dystrofiiniä lihaksista tulee hyvin alttiita vaurioille, jonka seurauksena on etenevä lihaskudoksen korvautuminen side- ja rasvakudoksella, toiminnan heikkeneminen sekä kardiomyopatia. Sairauteen ei ole vielä olemassa parantavaa hoitoa, ja hoitojen tarkoituksena onkin oireiden kontrollointi sekä elämänlaadun parantaminen. Sairauden synnyn ja uusien hoitomuotojen etsimiseen hyödynnetään erilaisia eläinmalleja, joista osalla esiintyy spontaaneja mutaatioita dystrofiinigeenissä ja osa on geneettisesti muokattuja. Yleisimmin käytetyt eläinmallit ovat mdx-hiirimalli (engl. X-linked muscular dystrophy mouse) sekä kultaisennoutajan lihasdystrofia -malli. Dystrofiinin puutoksen aiheuttavia mutaatioita on kultaisennoutajan lisäksi todettu useilla muilla koiraroduilla, ja usein sairauden löytyminen uusissa roduissa on seurausta eläinlääkärissä heränneestä epäilystä.
-
(2016)This study focuses on the developments of the Roman Catholic Church, particularly its emergence as a persecuted sect, all the way to becoming a respected institution, the official religion of the Empire, which gave continuity to the role of imperial power with global ambitions and dimensions. It is generally agreed by historians that the Holy Roman Empire started in the year 800 AD, via the coronation of Charlemagne by pope Leo III at the St. Peter’s Basilica in Rome. This thesis argues that such empire, even if at first devoid of bona fide structures that would render an imperial title appropriate, in fact had its beginnings much earlier than in the 8th century. Throughout this study, key dates are presented and shed light upon, so as to support the claim that already in the 4th century a Church establishment was growing exponentially, in terms of membership, wealth, and reputation, particularly through crucial imperial decrees that lent further credence to religious authorities in their claims of legal basis and divine right to govern the west. With focus on political measures and achievements on the part of the Church authorities, with special attention to the papacy, the concept of imperial regency is used to explain the many centuries necessary for the empire to be brought back. It was the Church the one actor capable of maintaining the Roman imperial legacy in the west after it fell in the 5th century. Despite having re-created the title of emperor, via an alliance with the powerful Franks, the Church, led by the pope, acted as the sole and real governor of a renovated, overwhelmingly Christian Empire.
-
(2019)Playing video games is a popular way to spend time and mobile gaming is one of the most growing entertainment industries in the world. Gaming is often associated with high level of motivation from the user as well as many negative and positive outcomes. Commitment towards games has invited countless of researches to examine what makes them so intriguing and motivating. This growing understanding gives developers more tools to design even better games and allows game-like features to be used in other contexts as well. This master’s thesis examines automatically gathered early log-data (n=100 000) from two free-to-play mobile games in order to create a model for retention. A model created using early log-data (first three days of play) creates opportunities to recognize potential players in an early phase and to evaluate early iterations of games that are in development. Furthermore, individual features are analyzed to study, what are the factors that influence coming back to the game at a later point (30 days after the installation of the game). The research questions in this thesis are: 1) Can commitment towards mobile games be modeled using early log-data? 2) How accurate predictions the created model can do? 3) What are the most important in-game features that predict retention? The model is created using a decision tree analysis, which was selected as a method due to its transparency and because it has been used before in earlier studies with similar designs. In both games, the rate of coming back to the game after 30 days of installation was 7.6%. A working model for retention was formulated which was able to predict coming back to the game with 33% accuracy. The most important in-game features that affect retention were the number of victories, the number of starts and the number of in-app-purchases during the three-day period after the game’s installation. Surprisingly, in-game rewards and achievements were the most insignificant features when predicting retention although they are often specifically designed to elevate user motivation. These results can influence design decisions made in game development by setting the focus on the factors that influence player commitment and behavior. Achievements and in-game rewards might feel too artificial and superficial compared to winning in game. If the system gives direct feedback of the effect of time and monetary sacrifice to the player’s performance, one might be able to reduce the number of players that decide to leave the game. The results also can be used to examine how game-like features are used in non-game systems where the goal is to tie together the high-level of motivation seen in games and socially impactful endeavors. Further studies of in-game behavior might also give new insights on game addiction and its negative effects on player well-being and business.
-
(2018)Background: The etiology of type 1 diabetes (T1D) is largely unknown. Infections and microbial exposures are believed to play a role in the pathogenesis and in the development of islet autoimmunity in genetically susceptible individuals. Objective: To assess the relationships between early childhood infections, islet autoimmunity, and progression to T1D in genetically predisposed children. Methods: Children with HLA-conferred disease susceptibility (N=790; 51.5% males) from Finland (n=386), Estonia (n=322), and Russian Karelia (n=82) were observed from birth up to the age of 3 years. Children attended clinical visits at the age of 3, 6, 12, 18, 24, and 36 months. Serum samples for analyzing T1D-associated autoimmune markers were collected and health data recorded during the visits. Results: Children developing islet autoimmunity (n=46, 5.8%) had more infections during the first year of life (3.0 vs. 3.0, mean rank 439.1 vs. 336.2; p=0.001) and their first infection occurred earlier (3.6 vs. 5.0 months; p=0.005) than children with no islet autoimmunity. By May 2016, seven children (0.9%) had developed T1D (progressors). Compared to non-diabetic children, T1D progressors were younger at first infection (2.2 vs. 4.9 months; p=0.004) and had more infections during the first 2 years of life (during each year 6.0 vs. 3.0; p=0.001 and p=0.027, respectively). By 3 years of age, the T1D progressors had twice as many infections as the other children (17.5 vs. 9.0; p=0.006). Conclusions: Early childhood infections may play an important role in the pathogenesis of T1D. Current findings may reflect either differences in microbial exposures or early immunological aberrations making diabetes-prone children more susceptible to infections.
-
(2020)Tutkielma käsittelee toiminnallisia tehtäviä varhennetun englannin opetukseen suunnatuissa oppikirjoissa Jump in ja Go. Vuosiluokkien 1-2 A1-kielen opetussuunnitelman perusteissa korostetaan, että opetuksessa tulisi korostua toiminnallisuus ja työtavoissa tulisi yhdistyä leikinomaisuus, musiikki, draama, pelit ja liike sekä eri aistien hyödyntäminen. Tutkielman tarkoituksena on selvittää, miten paljon ja millaisia toiminnallisia tehtäviä varhennetun englannin oppimateriaaleissa on, sekä millaisia elementtejä nämä toiminnalliset tehtävät sisältävät. Aiemmat tutkimukset ovat osoittaneet, että toiminnalliset työtavat voivat tukea oppimista ja ovat myös varhennettua kieltä opettavien opettajien suosimia tehtävätyyppejä. Aineistona tutkimuksessa käytettiin Otavan Jump in -oppimateriaalia sekä Sanoma Pron Go -oppimateriaalia, jotka on molemmat suunnattu varhennetun englannin opetukseen. Tutkielmassa analysoitiin oppilaille tarkoitettuja oppikirjoja sekä opettajan digiopetusmateriaalia, mutta vain oppikirjojen sisältämät tehtävät analysoitiin yksityiskohtaisesti. Oppikirjojen toiminnalliset tehtävät analysoitiin fokusoiden niiden sisällöllisiin elementteihin. Analysoidut sisältöelementit olivat liike, musiikki, kirjoittaminen, lukeminen, draama sekä värittäminen/piirtäminen. Pelit luokiteltiin toiminnallisiksi tehtäviksi, mutta ne analysoitiin erikseen niiden suuren määrän vuoksi. Tutkimuksen pohjalta voidaan todeta, että molemmat oppimateriaalit sisälsivät toiminnallisia tehtäviä, mutta tehtävät ja niiden elementit olivat erilaisia. Liike ja puhuminen olivat yleisimmät elementit toiminnallisissa tehtävissä, kun taas peleissä puhuminen oli yleisin elementti. Oppimateriaalien välillä oli myös eroavaisuuksia, sillä Go -oppikirjan toiminnalliset tehtävät sisälsivät enemmän draamaelementtejä, kun taas Jump in -oppikirja otti paremmin huomioon oppilaat, joiden lukutaito ei ole vielä vahva.
-
(2017)Tutkimuksen tavoitteena on selvittää millaisia opetusmenetelmiä ja työtapoja käytetään ensimmäisen luokan varhennetun englannin kielen opetuksessa suomalaisissa kouluissa, sekä verrata miten ne eroavat kolmannen luokan A1-englannin kielen opetuksesta. Lisäksi tutkin millä tavoin ikäspesifiset vaatimukset on huomioitu opetuksessa; mikä on äidinkielen ja kohdekielen suhde opetuksessa ja opetusaktiviteeteissa; millaisia aktiviteetteja näihin opetusmenetelmiin ja työtapoihin sisältyy; mitä opetusmateriaaleja käytetään varhennetussa englannin kielen opetuksessa; sekä millaisia motivaatiostrategioita on mahdollisesti nähtävissä varhennetussa kielenopetuksessa. Tutkielman teoriaosuudessa käsittelen niitä opetusmenetelmiä ja työtapoja, joita aineistossa on käytetty tai jotka ovat aineiston analyysin kannalta tärkeitä. Näistä merkittävimmät ovat viestinnällinen kieltenopetus, kielisuihku/kielisuihkutus, Total Physical Response (TPR) -menetelmä sekä Audiolingvaalinen menetelmä. Lisäksi esittelen aiempia tutkimuksia varhennetusta kieltenopetuksesta. Tutkielma on laadullinen tapaustutkimus. Aineisto kerättiin äänittämällä, videoimalla ja havainnoimalla kolmea varhennetun englannin kielenopetuksen ryhmää kahdessa koulussa sekä havainnoimalla kahta kolmannen luokan A1-englannin ryhmää. Havainnoinnin apuna käytettiin observointilomaketta, jossa oli valmiita kategorioita. Observointien jälkeen näiden luokkien opettajia haastateltiin täydentämään havainnointia sekä selvittämään heidän näkemyksiään ja asenteitaan. Aineisto kerättiin marras-joulukuussa 2015. Aineisto litteroitiin opettajan osalta kokonaan ja oppilaiden kohdalla osittain. Tämän jälkeen havainnointiaineisto luokiteltiin, observointilomakkeen kategorioita päivitettiin sekä analysoitiin etsien vastauksia tutkimuskysymyksiin. Haastattelut litteroitiin, käännettiin suomenkielisten vastausten osalta englanniksi ja analysoitiin. Tuloksista käy ilmi, että varhennetussa englannin kielenopetuksessa käytetään ensisijaisesti kielisuihkutusta, TPR-menetelmää ja toistamisharjoituksia. Tutkimukseen osallistuneella kolmannella luokalla sen sijaan ei ollut käytössä mitään selkeää opetusmenetelmää ja opetus oli oppikirjalähtöistä. Varhennetussa kieltenopetuksessa ikäspesifiset vaatimukset oli huomioitu painottamalla suullisia taitoja ja pelillisyyttä. Varhennetussa kieltenopetuksessa koulussa B äidinkielen ja kohdekielen suhde oli n. 50/50, mutta koulussa A äidinkieltä käytettiin runsaammin kuin kohdekieltä. Tyypillisimmät aktiviteetit koulussa A olivat kulutetun ajan mukaan pelit ja leikit sekä kertojen mukaan erilaiset toistamisharjoitukset. Koulussa B erilaiset pelit olivat yleisimmät aktiviteetit sekä ajallisesti että kertojen mukaan. Koulussa A käytettiin runsaasti interaktiivisen valkotaulun ohjelmistoa, digitaalista ääntä tai musiikkia, sekä kuvia. Koulussa B käytettiin myös interaktiivista valkotaulua, mutta ohjelmisto oli suppeampi. Koulussa B oli hieman laajemmin erilaisia opetusmateriaaleja.
-
(2022)Tutkielma tutkii varhentamisen hanketta alakoulun englanninopetuksessa. Vuodesta 2020 lähtien tuli voimaan muutos, jonka mukaan A1 kielen opiskelu alkaa Suomessa jo ensimmäiseltä luokalta lähtien. A1 kieli on useimmiten englanti, mutta se voi olla myös jokin muu kieli, kuten saksa tai ranska. Varhennettua kieltä opetetaan yleensä yksi tunti viikossa. Joissakin kouluissa varhennettua kieltä on opetettu jo aikaisemmin, mutta maanlaajuinen muutoksesta on tullut vasta viime vuosina. Kielenopetuksen aloittaminen jo ensimmäiseltä luokalta lähtien perustuu oppimisen eri herkkyyskausiin. Joidenkin tutkimustulosten mukaan kielitaito tarttuu lapsiin parhaiten mahdollisimman nuorena. Koska aihetta ei ole vielä tutkittu paljoa opettajien tai opetusharjoittelijoiden näkökulmasta, tutkimukseni keskittyy heidän asenteisiinsa varhennetun englannin opetusta koskien. Tutkin myös, mitä hyötyjä ja haittoja varhennetun kielen opetuksesta on löydetty aiemmissa tutkimuksissa. Käsittelen sekä Suomen kontekstiin sijoittuvia tutkimuksia, että kansainvälisiä tutkimuksia. Tutkimuksen tavoitteena oli selvittää lisäksi, miten varhennettua englanninopetusta Suomessa voitaisiin kehittää tulevaisuudessa. Opettajien ja opetusharjoittelijoiden mielipiteiden keräämiseksi loin sähköisen kyselyn Google Formsilla. Aineisto kerättiin tammi-helmikuussa 2022. Kysely koostui kahdesta osasta, joista ensimmäinen osa oli suunnattu opettajille ja toinen opetusharjoittelijoille. Kyselyllä kartoitettiin molempien kohderyhmien näkemyksiä varhennetun englannin kielen opettamiseen alakoulussa. Kysymykset koskivat varhennetun kielenopetuksen kokemuksia, kuten oppilaiden motivaatiota kielen oppimiseen ja opettajien kokemia haasteita luokassa. Tutkimuksen tulokset osoittavat, että kielenopiskelun aloittaminen aikaisemmin on kannattavaa, jos tietyt kriteerit oppimiselle otetaan huomioon. Sekä oppilaille että opettajille tulee tarjota optimaaliset olosuhteet varhennetun kielenopetukseen kouluissa. Tämä koskee muun muassa oppimisympäristöä, ryhmäkokoja sekä englannin opettamista lapsille soveltuvalla tavalla. Suuria ryhmäkokoja tulisi välttää, sillä ne johtavat eriyttämiseen ja sen tuomiin ongelmiin. Lisäksi englantia tulisi opettaa 1. – 2. luokalla suullista ilmaisua sekä toiminnallisuutta painottaen. Opettajien mielipiteistä käy ilmi, että vaikka suurin osa kokee varhennetun englannin opettamisen mielekkääksi, tarjotaan myös useita parannusehdotuksia varhennettuun opetukseen. Opettajat toivoivat pienempiä ryhmiä, lisää sopivaa opetusmateriaalia sekä selkeitä toimintatapoja varhennettuun opetukseen. Tutkimustuloksista käy myös ilmi varhennetun englannin opetuksen hyödyt ja haitat kouluympäristössä sekä aiempien tutkimusten suhde nykytutkimukseen.
-
(2021)Objectives: Bisphenol A (BPA) is commonly used plasticizer that has endocrine disrupting properties. Fetal exposure to BPA has been associated with offspring behavioural problems. These associations may be mediated through BPA-induced alterations in the offspring DNA methylation (DNAm). This study examined whether fetal BPA exposure associates with behavioural problems and whether DNAm biomarker score for early pregnancy BPA exposure is linked with behavioural problems in the offspring. Methods: Participants were 442 mother-child pairs of the Finnish PREDO-cohort. I measured BPA from the early pregnancy urine samples and assayed DNAm in the cord blood with Illumina 450k or EPIC array. Mothers reported behavioural problems of their offspring with the Child Behaviour Checklist/1.5-5 (CBCL/1.5-5) at the mean child age of 3.8 years (SD = 1.0 years). I used LASSO regression to create a DNAm score for early pregnancy BPA exposure and tested the associations between BPA exposure, the DNAm score, and CBCL/1.5-5 scores with linear and logistic regressions. Results: After adjustments, early pregnancy BPA exposure was associated with higher risk for clinically meaningful internalizing (p = .02) and externalizing (p = .04) behavioural problems in the offspring. The DNAm score included eight CpG sites, explained 4.8% of the BPA variation, and was borderline significantly associated with a risk for clinically meaningful internalizing (p = .05) and externalizing behavioural problems (p = .06). Conclusions: Early pregnancy BPA exposure associated and DNAm biomarker for BPA exposure borderline associated with offspring behavioural problems. DNAm biomarker score for fetal BPA exposure showed promise and should be studied further in subsequent studies.
-
(2014)Natural disturbances are important for regeneration and biodiversity of forests. Restoration imitates natural disturbances in order to return ecosystems towards its natural state. Knowledge is lacking about the efficiency of restoration, as well as early tree successions. The objects of this study were to investigate the effects of fire and coarse woody debris (CWD) increment on early tree succession and tree species diversity along forest – gap gradient 10 years after restorative partial cuttings in southern Finland. Seedling densities and heights, microhabitat distributions and tree species diversity were compared between four restoration treatments; unburned treatments with 5 and 60 m3 CWD ha-1, and burned treatments with 5 and 60 m3 CWD ha-1. Total seedling densities were tested with two-way analysis of variance. Species diversity was analyzed by species richness and Shannon index, which were tested with two-way analysis of variance. In general, the burned treatments included higher seedling densities and higher seedlings. The different amounts of dead wood revealed differences in deciduous tree species. The density of birch was higher in the treatments with 60 m3 CWD ha-1 and the heights of birch and other deciduous tree species were higher in burned treatment with 60 m3 CWD ha-1. Pine and birch were abundant in the burned treatments. The densities of spruce were very high in the unburned treatment with 5 m3 CWD ha-1, but fairly low in the other treatments. The seedling densities and heights were the lowest in the forest. Seedling densities did not vary significantly between the edge and gap segment. Microhabitat distributions of the coniferous seedlings differed between the unburned and burned treatments, but no clear differences were observed between the low (5 m3 ha-1) and high amount (60 m3 ha-1) of CWD. Microhabitat distributions of seedlings between forest, edge and gap did not differ noticeably, except with spruce in the burned treatments between the edge and gap. Tree species diversity of regeneration was slightly higher in the burned than in the unburned treatments. Different amounts of CWD did not affect the tree species diversity. The tree species diversity was significantly lower in the forest than in the treatment area, but it did not differ between the edge and gap. The results indicate that early tree succession is likely to be more abundant after burning than without. Fire as a restoration tool can be suggested for the regeneration of pine and birch. Dead wood appears to be insignificant for early tree succession. The limited size of restoration areas does not impede the tree succession, since the densities and heights of seedlings were generally the highest near the forest edge. Fire might increase tree species diversity.
-
(2021)Earnings insurance is a measure of how much earnings of a worker change relative to idiosyncratic shock to firm performance. In case of full earnings insurance, shocks are not passed onto earnings at all and otherwise earnings insurance is partial. Linked employer-employee data is widely used in this recent empirical research interest due to its rich nature. This paper explores earnings insurance in Finland by focusing on three aspects: how much firms in Finland provide earnings insurance, are there differences in levels of earnings insurance between industries and whether partial earnings insurance is driven by hours worked or hourly wage. The main findings are that firms in Finland provide partial but substantial earnings insurance in all industries and that hours worked play a smaller role than hourly wage in determining partial earnings insurance. Because data on hours worked is not available in many countries, this paper is able to bring new insight on the role of hours worked and hourly wage in the composition of partial earnings insurance. However, hours worked and hourly wage explain only around half of partial earnings insurance, so the result should be considered with caution.
Now showing items 4630-4649 of 33008