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  • Public defence: 2017-05-24 09:00 Triple Helix, Samverkanshuset, Umeå
    Åström, Christofer
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Health effects of heatwaves: short and long term predictions2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Background: Climate change is defined by the Intergovernmental Panel on Climate Change as changes in the state of the climate associated with changes in the mean and/or the variability of its properties. Climate change will affect temperatures both as an increase in mean temperature as well as changes in the frequency of temperature extremes. Health effects associated with extreme heat, both mortality and morbidity, have been observed all over the globe. Groups that are often found to be more vulnerable are the elderly and people diagnosed with certain diseases and/or on taking some specific types of medication. The health effects from climate change in the future depend on a number of underlying sociodemographic and other factors. It is difficult to predict how the underlying societal factors that are likely to alter the health effects from high temperatures will change. The aim of this thesis is to investigate the influence of the underlying assumptions and factors that are key components when predicting and projecting heat-related illness, both in the short and long term. This work aims to identify and to some extent quantify different sources of uncertainty that will have effects on the outcome of health impact assessments.

    Methods: We wanted to evaluate if different statistical models would alter the ability to identify days with elevated heat-related risk. We used observations of temperatures and daily mortality for Greater Stockholm to model different exposure-response relationships (Paper I). Along the observed data, we collected temperature forecasts for the Stockholm area. We defined what constitutes a risk day and compared the model’s ability to identify these days using both observed and forecasted temperatures to evaluate the predictive performance of models based on the different statistical approaches. To estimate how climate change will alter the heat-related health impacts we used climate change projections from a range of climate change scenarios to be able to get stable estimates as well as a measure of the uncertainty in the climate projections (Paper II-III). We estimated the change in respiratory hospital admissions (Paper II) and the future need for adaptation to keep heat-related mortality at current levels (Paper III) in Europe. We also estimated the change in heat-related mortality due to changes in climate, demographics and health status of the population in Stockholm (Paper IV).

    Results: The models using a highly complex exposure-response relationship showed lower predictive performance, especially when looking at a longer time-scale. The more complex models did also estimate a lower mortality increase compared to the less complex ones. There was however high agreement of which days to be considered risk days. The estimated increase in heat-related illness from the three health impact assessment studies showed impacts on a similar order of magnitude when looking at changes in climate only. Respiratory hospital admissions were estimated to more than double in Europe and heat-related mortality in Stockholm was estimated to increase to around 257% of current levels. Therefore, adaptation needs to lower the vulnerability to heat by around 50% in the European countries. In study III and IV we take changes in demographics into account and find that the future health burden from heat will increase due to the growing elderly population.

    Conclusion: To be able to make predictions of future health burdens from heat, both in the long and short term, we need to consider the properties of the epidemiological models and how the choice of model might limit its use within a health impact assessment. Climate change seems to be the main driver of the future health burden from extreme temperatures, but our results suggests that changing demographics will add to the burden considerably unless relevant adaptation measures are implemented. Adding this on top of the challenges posed by climate change, we find that need for adaptation will increase substantially in the future.

  • Public defence: 2017-05-24 13:00 KB.E3.03 (KB3B1, Stora hörsalen), Umeå
    Stangl, Zsofia Réka
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå Plant Science Centre.
    Acclimation of plants to combinations of abiotic factors: connecting the lab to the field2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Increasing atmospheric CO2 and other greenhouse gasses coupled to the accelerated rate of global warming puts plants and ecosystems under the strain of a rapidly changing abiotic environment. Understanding the impacts of changing global climate is a strong focus of plant science and the establishment of more resilient crop variants is an important goal for breeding programs. Our understanding of plant responses and acclimation to abiotic conditions has improved substantially over the last decades but the combination of a complex abiotic environment and high biological diversity, both on molecular as well as on species level, leaves us still with a lot of uncertainties. The aim of this doctoral thesis was to establish a link between plant thermal responses and the carbon-nitrogen balance of plants. The work in this thesis focused on ecologically significant species of the boreal region: Picea abies, Pinus sylvestris and Betula pendula; and Betula utilis, which is one of the prominent tree species in the high altitudes of the Himalayas. The results presented demonstrate that sub-optimal temperatures combined with other abiotic factors can have additive effects that are not easily deducible from the effect of the two factors separately. Low nitrogen availability enhanced the negative effect of low temperature, while elevated CO2 enhanced plant growth under moderate increases in temperatures but under a more extreme temperature increase it exacerbated the negative effect of heat. I also show evidence that species, despite being grouped into the same functional group or inhabiting the same biome can have different thresholds to temperature and to shifts in the C/N balance of their environment and that these differences can, to some extent, be explained by their differential growth strategies. Furthermore, I demonstrate results supporting the hypothesis that the C-N fluxes between mycorrhizal fungi and tree are strongly dependent on the C and N in the environment, highlighting the significance of the tree-mycorrhiza associations in the C sequestration capacity of the boreal region. In this thesis I also present a generalised empirically based mathematical model that can describe the respiration-temperature response of plant functional types or biomes with high precision, giving a more accurate estimate of NPP when implemented in global climate models, and has the potential to incorporate the thermal acclimation of respiration, further increasing the precision of estimating carbon fluxes under future warming temperatures. My results provide novel insights into the interactive temperature-carbon-nitrogen responses of plants, taking a step towards better understanding the response of plants and forests to future climates.

  • Public defence: 2017-05-26 13:00 N420, Naturvetarhuset, Umeå
    Yung, I
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Automation of front-end loaders: electronic self leveling and payload estimation2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    A growing population is driving automatization in agricultural industry to strive for more productive arable land. Being part of this process, this work is aimed to investigate the possibility to implement sensor-based automation in a particular system called Front End Loader, which is a lifting arms that is commonly mounted on the front of a tractor. Two main tasks are considered here, namely Electronic Self Leveling (ESL) and payload estimation. To propose commercially implementable solutions for these tasks, specific objectives are set, which are: 1) to propose a controller to perform ESL under typical disturbances 2) to propose a methodology for payload estimation considering realistic estimation conditions. Lastly, aligned with these goals, 3) to propose models for the Front End Loader under consideration for derivation of solutions of the specified tasks.

    The self-leveling task assists farmers in maintaining the angular position of the mounted implements, e.g. a bale handler or a bucket, with respect to the ground when the loader is manually lifted or lowered. Experimental results show that different controllers are required in lifting and lowering motions to maintain the implement's angular position with a required accuracy due to principle differences in gravity impact. The gravity helps the necessary correction in lifting motion, but works against the correction in lowering motions. This led us to propose a controller with a proportional term, a discontinuous term and an on-line disturbance estimation and compensation as well as the tuning procedure to achieve a 2 degrees tracking error for lowering motions in steady state. The proposed controller shows less sensitive performance to lowering velocity, as the main disturbance, in comparison to a linear controller.

    The second task, payload estimation, assists farmers to work within safety range as well as to work with a weight measurement tool. A mechanical model derived based on equations of motion is improved by a pressure based friction to sufficiently accurately represent the motion of the front end loader under consideration. The proposed model satisfies the desired estimation accuracy of 2\% full scale error in a certain estimation condition domain in constant velocity regions, with off-line calibration step and off-line payload estimation step. An on-line version of the estimation based on Recursive Least Squares also fulfills the desired accuracy, while keeping the calibration step off-line.

  • Public defence: 2017-06-01 13:00 KB3A9, KBC huset, Umeå
    Manuel, Alzira Andre Munguambe
    Umeå University, Faculty of Science and Technology, Department of Science and Mathematics Education.
    Non-Formal Vocational Education and Training in Mozambique: Contexts, policies, pedagogies and contradictions2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Education and training in Mozambique are considered to be a ‘right’ and a ‘duty’ for all its citizens. Non-Formal Vocational Education and Training (NFVET) has been promoted to increase educational opportunities for more citizens, particularly the most vulnerable groups- the out of school and unemployed.

    The aim of this study is to gain a deeper insight into NFVET in Mozambique, explore its context and historical development, and to identify factors that could contribute to the improvement of this area of education. It is a qualitative, exploratory study carried out in Mozambique. Semi-structured interviews, focus group interviews, non-participant observations, analysis of both printed and electronic documents and life story narratives of research participants were used as methods of data collection. The theories and concepts of adult education and Cultural Historical Activity Theory (CHAT) constituted the theoretical framework of the study.

    The findings of the study reveal that NFVET is highly relevant in the context of change and development in Mozambique. This area of education plays an increasingly relevant role in helping people to continually improve their skills and contributes to their empowerment and social inclusion. However, contextual factors such as lack of resources, teachers’ poor professional competencies and weak linkages between the training programmes and the labour market constitute the main barriers for the attainment of the objectives of these programmes.

    The study concludes that framework and activities of NFVET need to be improved. This improvement includes strengthening existing policies, the need for the professionalisation of educators by enhancing their competencies and the improvement of their working conditions. Further, the development and provision of new curriculum and material taking into account the learners’ needs, the local context and the demands of the labour market are needed. The establishment of functional partnerships between NFVET providers and systematic participative evaluation of the training programmes are also suggested to ensure the quality and sustainability of the programmes.

     

  • Public defence: 2017-06-01 13:00 Major Groove, Umeå
    Spoerry, Christian
    Umeå University, Faculty of Medicine, Department of Molecular Biology (Faculty of Medicine). Umeå University, Faculty of Medicine, Umeå Centre for Microbial Research (UCMR).
    Streptococcal immunoglobulin degrading enzymes of the IdeS and IgdE family2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Bacteria of the genus Streptococcus are common asymptomatic colonisers of humans and animals. As opportunistic pathogens they can however, depending on their host’s immune status and other circumstances, cause mild to very severe infections. Streptococci are highly intertwined with specific host species, but can also cause zoonosis or anthroponosis in more uncommon hosts. Prolonged and reoccurring infections require immune evasion strategies to circumvent detection and eradication by the host’s immune defence. A substantial part of the immune defence against bacterial pathogens is mediated by immunoglobulins. This thesis is based on work to identify and characterise immunoglobulin degrading enzymes secreted by different Streptococcus species as a means to sabotage and evade antibody-mediated immune responses.

    Stoichiometric and kinetic analysis of the IgG degrading enzyme IdeS from the important human pathogen S. pyogenes revealed that IdeS cleaves IgG, opposed to previous publications, as a monomer following classical Michaelis-Menten kinetics.

    The IdeS homologue of S. suis, IdeSsuis, did however not cleave IgG, but was highly specific fo rporcine IgM. S. suis was found to possess yet another protease, IgdE, capable of cleaving porcine IgG. Both of these proteases were shown to promote increased bacterial survival in porcine blood during certain conditions.

    IgdE is the founding member of a novel cysteine protease family (C113). Novel streptococcal members of this protease family were shown to specifically degrade certain IgG subtypes of the respective Streptococcus species’ main host. The observed substrate specificity of IgdE family proteases reflects the host tropism of these Streptococcus species, thereby giving insights into host-pathogen co-evolution.

    The abundance of immunoglobulin degrading enzymes among Streptococcus species indicates the importance of evasion from the antibody mediated immune responses for streptococci. These novel identified immunoglobulin degrading enzymes of the IdeS and IgdE protease families are potential valid vaccine targets and could also be of biotechnological use.

  • Public defence: 2017-06-02 09:00 Betula, Umeå
    Sgaramella, Nicola
    Umeå University, Faculty of Medicine, Department of Medical Biosciences, Pathology.
    Squamous cell carcinoma of the oral tongue: studies of biomarkers connected to human papillomavirus infection, epithelial to mesenchymal transition and locoregional metastatis2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Background: Oral Tongue Squamous Cell Carcinoma (OTSCC) is the most frequent and aggressive carcinoma in the head and neck region. Its incidence has increased during the last decades, especially in young patients (40 years) mainly female. These young patients have either not been exposed to the traditional risk factors for this disease, or have a much reduced duration of exposure than the typical OTSCC patient. The reasons behind this increasing incidence remain unknown.

    The aims of this thesis were to analyse the presence and possible role of human papillomavirus (HPV) in oral tongue cancer in correlation with its surrogate marker p16 and its receptor syndecan-1. Other aims were to evaluate expression of EMT (epithelial to mesenchymal transition) - related markers, such as E-cadherin, β-catenin, CK5 and CK19, and to address the potential predictive role of podoplanin in the loco-regional metastatic process.

    Clinical parameters including age, sex, geographical distribution, relapse, tumour staging and grading were also investigated for a possible correlation with biomarker expression and prediction of survival rate and therapeutic strategy.

    Materials and methods: More than one hundred samples of OTSCC coming from two University Hospitals of two different countries (Sweden and Italy) were analysed. HPV presence was evaluated by in situ hybridisation for detection of the high-risk HPV 16 and indirectly by immunohistochemistry (IHC) of its surrogate marker p16. Expression of the HPV receptor syndecan-1 and the EMT biomarkers E-cadherin, β-catenin, CK5, CK19 were also evaluated by immunohistochemistry.

    Samples were scored using a quick score (QS), taking both number and intensity of cells stained into account. Podoplanin expression was investigated at both protein and RNA level.

    Results: Tumour size and lymph node metastasis correlated to both overall and disease-free survival. Despite variable expression of the syndecan-1 receptor, HPV 16 was not detected in any sample analysed, excluding a possible association with p16, which was expressed in 33% of the cases.

    All EMT-related markers were commonly expressed in tongue cancer. Data showed E-cadherin to be an independent prognostic factor with higher expression associated with poor overall survival. Notably, E-cadherin, β-catenin and CK5 directly correlated to each other.

    Multivariate analysis of clinical data demonstrated that age of the patient is an independent prognostic factor with younger patients showing a worse survival rate. Patients younger than 40 years also showed significantly higher expression of podoplanin. Data for geographic distribution revealed a difference in expression of E-cadherin between Swedish and Italian patients.

    Conclusions: In contrast to SCC of the base of the tongue and the tonsil, HPV is not present in OTSCC, excluding HPV infection as a risk factor. Higher levels of E-cadherin and young age is associated with poor survival in OTSCC patients. The different frequency of EMT markers seen between Swedish and Italian patients suggests an important role for the environment and the geographical area in the onset of different molecular patterns of OTSCC.

  • Public defence: 2017-06-02 09:00 Hörsal B, byggnad 1D, 9tr, Norrlands Universitetssjukhus, Umeå
    Danielsson Borssén, Åsa
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Autoimmune hepatitis: life, death and in-between2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Background Autoimmune hepatitis (AIH) is a chronic autoimmune liver disease that is overrepresented in women (75% of cases). Studies have described a 10-year survival after diagnosis near to that of the general population, but less is known about the long-term survival. The inflammation in AIH causes fibrotic tissue to form in the liver and about 1/3 of AIH patients have cirrhosis at diagnosis. Studies have shown that treatment of the underlying liver disease can reverse fibrosis, and sometimes even cirrhosis, but only a few studies have examined the response to treatment in AIH. AIH affects all ages and some women will have cirrhosis during pregnancy, which is a risk factor for an adverse outcome. Cirrhosis is also a risk factor for hepatocellular carcinoma (HCC), but the true risk for HCC in cirrhotic AIH patients is not known.

    Aim To study the epidemiology of AIH in Sweden, the causes of death and the risk of cancer for AIH patients, the efficacy of medical treatment on fibrosis and cirrhosis, and outcomes for the mother and child in pregnancy.

    Material and methods A cohort of 634 AIH patients was established at the Swedish University hospitals. Prevalence and incidence were calculated, and a relative survival analysis was performed in which survival after AIH diagnosis was compared to that of the general population. Causes of deaths were retrieved from the Cause of Death Registry.

    The Cancer Registry was used to calculate standard incidence ratios (SIR) and compare cancer risk to that of the general population.

    Two hundred fifty-eight liver biopsies from 101 patients were analyzed by a single pathologist and classified according to the Ishak grading and staging system. Liver histology was stratified according to the temporal changes of fibrosis stage, and groups were compared.

    A questionnaire was answered by 138 women with AIH about medication, pregnancies, disease behavior during and after pregnancy, and pregnancy outcomes.

    Results The incidence and prevalence of AIH were 1.2/100 000 and 17.3/100 000 respectively. The relative survival started to decline after 4 years compared to the reference population, and was even more pronounced after 10 years. Men were diagnosed (33.5 years versus 48.0 years, p<0.001) and died (59.7 versus 75.4 years, p=0.002) at a younger age than women. Patients with cirrhosis at diagnosis had an inferior survival (p<0.001). Liver-related death was the most common cause of death (32.7%). Among AIH patients a higher incidence of cancer was found compared with that of the general Swedish population, SIR of 2.08 (95% Confidence Interval (CI) 1.68-2.55). SIR for non-melanoma skin cancer was 9.87 (95% CI 6.26-14.81) and hepatobiliary cancer was 54.55 (95% CI 19.92-99.99). HCC was found in 4% of the cirrhotic patients and the incidence rate was 0.3% per year. A reduction of fibrosis stage from first to last biopsy was common (62.4% of patients) and patients on a continuous glucocorticoid medication more often had a decreased fibrosis stage than those with withdrawal attempts (p=0.002). One hundred children were born by 58 women with AIH, of which 23 women had 43 children after diagnosis of cirrhosis. Malformations were reported in 3%, and pre-term births (<week 38) in 22% of the pregnancies. Cirrhotic women gave birth without more complications than others, but with a higher frequency of caesarean sections than non-cirrhotic women (p=0.047).

    Conclusion Contrary to previous reports, AIH patients’ life expectancy was significantly inferior to that of the control population already 4 years after onset of disease, and liver disease was the most common cause of death. AIH patients had an overall enhanced risk for cancer, mainly from an increased risk of non-melanoma skin cancer and HCC. However, the annual risk of HCC was only 0.3% in cirrhotic patients. Histological improvement of liver fibrosis was common in AIH. The proportion of pre-term births was high, but overall pregnancy and childbirth appear to be safe in AIH, even in compensated cirrhosis. 

  • Public defence: 2017-06-02 09:00 KB.E3.03 (stora hörsalen), Umeå
    Engdahl, Cecilia
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Selective inhibition of acetylcholinesterase 1 from disease-transmitting mosquitoes: design and development of new insecticides for vector control2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Acetylcholinesterase (AChE) is an essential enzyme with an evolutionary conserved function: to terminate nerve signaling by rapid hydrolysis of the neurotransmitter acetylcholine. AChE is an important target for insecticides. Vector control by the use of insecticide-based interventions is today the main strategy for controlling mosquito-borne diseases that affect millions of people each year. However, the efficiency of many insecticides is challenged by resistant mosquito populations, lack of selectivity and off-target toxicity of currently used compounds. New selective and resistance-breaking insecticides are needed for an efficient vector control also in the future. In the work presented in this thesis, we have combined structural biology, biochemistry and medicinal chemistry to characterize mosquito AChEs and to develop selective and resistance-breaking inhibitors of this essential enzyme from two disease-transmitting mosquitoes.We have identified small but important structural and functional differences between AChE from mosquitoes and AChE from vertebrates. The significance of these differences was emphasized by a high throughput screening campaign, which made it evident that the evolutionary distant AChEs display significant differences in their molecular recognition. These findings were exploited in the design of new inhibitors. Rationally designed and developed thiourea- and phenoxyacetamide-based non-covalent inhibitors displayed high potency on both wild type and insecticide insensitive AChE from mosquitoes. The best inhibitors showed over 100-fold stronger inhibition of mosquito than human AChE, and proved insecticide potential as they killed both adult and larvae mosquitoes.We show that mosquito and human AChE have different molecular recognition and that non-covalent selective inhibition of AChE from mosquitoes is possible. We also demonstrate that inhibitors can combine selectivity with sub-micromolar potency for insecticide resistant AChE.

  • Public defence: 2017-06-02 10:00 Hörsal E, Umeå
    Knospe, Yvonne
    Umeå University, Faculty of Arts, Department of language studies.
    Writing in a third language: a study of upper secondary students’ texts, writing processes and metacognition2017Doctoral thesis, monograph (Other academic)
    Abstract [en]

    Learning an additional foreign language (usually referred to as a third language, L3) after English (L2) in formal settings seems to remain relatively unsuccessful in the European context (European Commission 2012), despite the reported advantages from extensive language learning experiences. Against this background the present thesis explores the potential benefits of a teaching approach focused on writing strategies and metacognitive reflections for L3 writing. The study investigates the influence of an intervention concerning the writing of argumentative texts in L3 German. Two classes with 15- and 16-year-olds from a Swedish upper secondary school participated. One class received writing instruction, the other one no special treatment. Texts were collected at three points in time. Additionally, seven students from the intervention class, the “focus students”, attended five individual writing sessions, in which their argumentative writing was recorded with keystroke logging and screen-recording software. After each writing session, individual stimulated-recall interviews were conducted. The development of L3 writing throughout the course of the intervention was investigated from three different perspectives: writing products, writing processes and metacognitive knowledge. Text quality was studied on the basis of a selection of class texts, which were scored both analytically and holistically. The writing processes were examined by automated and manual analysis of the conducted log- and screen-recording files. Metacognitive knowledge was analysed based on transcripts of stimulated-recall interviews. The findings show that only the texts of those students, who attended both the intervention and the individual writing sessions, including reflective interviews, improved in quality during the intervention. Further, these students slightly increased their writing fluency through higher text production rate and a shift from intense online-source use to more revisions. The investigation of metacognitive knowledge revealed a number of learner- and language-related variables, which seem to be decisive in understanding the interplay between learners’ attitudes, performance and strategic behaviour. The results suggest that writing practice is crucial, but learning to write can be further enhanced by including writing strategy instruction and metacognitive reflections in the foreign language classroom.

  • Public defence: 2017-06-02 10:00 Lilla hörsalen, KB3A9, Umeå
    Papazian, Stefano
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå Plant Science Centre.
    Black mustard and the butterfly effect: metabolomics of plant-insect interactions under multiple stress conditions2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    One main goal of ecological research is to understand nature´s complexity, in order to predict the potential impact of environmental perturbations. In this thesis, I investigate the ecological interactions between some of the most ancient organisms living on our planet: plants and insects.

    Focus of my research is the interaction between the wild brassicaceous plant black mustard (Brassica nigra L.) and its specialist insect herbivore, the large white cabbage butterfly (Pieris brassicae L). Both organisms are well characterized model species used in chemical ecology research.

    Using different analytical techniques, such as liquid and gas chromatography coupled to mass-spectrometry (LC- and GC-MS) and headspace collection of volatile organic compounds (VOCs), I apply the approach of metabolomics and systems biology to the field of ecology to explore the metabolic changes occurring inside the plants exposed to biotic and abiotic stresses.

    Particularly, I study the plant metabolic responses against P. brassicae chewing caterpillars during sequential treatment exposure to: abiotic stress by the oxidative air pollutant ozone (O3); dual herbivory with specialist Brevicoryne brassicae piercing-sucking aphids; and chemical induction of plant defences with the oxylipin phytohormone methyl-jasmonate (MeJA).

    Results show how during herbivore-induced responses, changes in defence- and growth-metabolic processes are tightly connected to stress protection mechanisms, indicating that plants actively reprogram their inner metabolic networks in order to adapt to consecutive changes in the environment.

    This thesis illustrates how evaluating the plant metabolome in its entirety rather than single metabolites, can help us understanding plant responses towards abiotic and biotic stresses, and improve our ability to predict how constant shifts in the environment affect plant physiology and ecology.

     

  • Public defence: 2017-06-02 13:00 Sal D, unod T9, byggnad 1D, plan 9, Umeå
    Lundberg, Elena
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Paediatrics.
    Growth hormone responsiveness in children: results from Swedish multicenter clinical trials of growth hormone treatment2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The general aims of the thesis were to study GH responsiveness by estimation of pharmacokinetics and bioavailability of injected recombinant human GH (rhGH), of growth response as gain in heightSDS during childhood and puberty, and IGF-I response as change in circulating IGF-ISDS and IGFBP3SDS. Methods Short children were recruited during 1988–1999 into two national randomized multicentre clinical trials on growth until adult height. A group of 117 GHD patients who had been treated from prepuberty with a single GH dose of 33μg/kg/day for at least 1 year were randomized at onset of puberty either to remain on this dose regimen or to an increased dose, GH67μg/kg/day, administered once daily or divided into two doses, GH33x2μg/kg/day. Data on IGF-ISDS and IGF binding protein 3 (IGFBP3)SDS were available from 111 patients and analysed as stated below. The 151 short prepubertal non-GHD patients were randomized into three groups: untreated controls, GH33 or GH67μg/kg/day. A subpopulation from both trials, 128 patients examined annually in Gothenburg, formed the study sample on GH uptake. They received sc GH injections to obtain 16–24 hour GH curves and the GH pharmacokinetics and bioavailability was calculated. Results: A dose-dependent effect on Cmax was found with great intra- and inter-individual variability. Of the Cmax variability, 43% was explained by the rhGH dose and proxies for injection depth. Median bioavailability of the injected dose was 71%, with great variation, mainly dependent on injection depth. In the IGHD group a dose-dependent difference in pubertal gain in heightSDS was found, with mean of 0.8 for the GH67 group and 0.4 for GH33, p<0.01. The mean total gain in heightSDS during treatment was 1.9 for GH67 and 1.4 for GH33, p<0.01. A dose-dependent pubertal ΔIGF-ISDS was 0.5 vs −0.1, p=0.007, correlating to pubertal gain in heightSDS, p=0.003; and was the most important variable to explain the variation in pubertal gain in heightSDS. In the non-GHD group the ΔIGF-ISDS from baseline to mean study level was dose-dependent 2.07 vs 1.20, p=0.001; and correlated negatively with baseline values of IGF-ISDS, rho= -0.56 for GH67, p=0.001, vs rho= -0.82 for GH33, p=0.0001, and correlated positively with gain in heightSDS in both GH-treated groups, rho= 0.42, p<0.001. In multivariable regression analyses, ΔIGF-ISDS was always an important explanatory variable for long-term growth response from the prepubertal period until adult height, while the IGF-ISDS study level per se was not. Conclusion: Growth response to GH treatment was dose dependent with great variability between patients. More pubertal growth was attained by an increased rhGH dose, mimicking the physiology of healthy children, in whom GH secretion rate increases during puberty. This resulted in a gain in IGF-ISDS closely correlating to pubertal gain in heightSDS in both IGHD and non-GHD patients. A broad range in GH responsiveness was found for both growth and IGF response in both diagnostic groups, but lower in the non-GHD group. Higher uptake of a given GH dose was observed after a deep injection and a higher GH concentration. These results are clinically applicable for individuals who remain short close to onset of puberty; by identifying and deeply injecting a rhGH dose that accounts for individual responsiveness, we can stimulate an increment in IGF-ISDS that correlates to gain in heightSDS during puberty.

  • Public defence: 2017-06-02 13:15 KB.E3.03, Stora Hörsalen, Umeå
    Khodabakhsh, Amir
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Fourier transform and Vernier spectroscopy using optical frequency combs2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Optical frequency comb spectroscopy (OFCS) combines two previously exclusive features, i.e., wide optical bandwidth and high spectral resolution, enabling precise measurements of entire molecular bands and simultaneous monitoring of multiple gas species in a short measurement time. Moreover, the equidistant mode structure of frequency combs enables efficient coupling of the comb power to enhancement resonant cavities, yielding high detection sensitivities. Different broadband detection methods have been developed to exploit the full potential of frequency combs in spectroscopy, based either on Fourier transform spectroscopy or on dispersive elements.There have been two main aims of the research presented in this thesis. The first has been to improve the performance of mechanical Fourier transform spectrometers (FTS) based on frequency combs in terms of sensitivity, resolution and spectral coverage. In pursuit of this aim, we have developed a new spectroscopic technique, so-called noise-immune cavity-enhanced optical frequency comb spectroscopy (NICE-OFCS), and achieved a shot-noise-limited sensitivity and low ppb (parts-per-billion, 10−9) CO2 concentration detection limit in the near-infrared range using commercially available components. We have also realized a novel method for acquisition and analysis of comb-based FTS spectra, a so-called sub-nominal resolution method, which provides ultra-high spectral resolution and frequency accuracy (both in kHz range, limited only by the stability of the comb) over the broadband spectral range of the frequency comb. Finally, we have developed an optical parametric oscillator generating a frequency comb in the mid-infrared range, where the strongest ro-vibrational molecular absorption lines reside. Using this mid-infrared comb and an FTS, we have demonstrated, for the first time, comb spectroscopy above 5 μm, measured broadband spectra of several species and reached low ppb detection limits for CH4, NO and CO in 1 s.The second aim has been more application-oriented, focused on frequency comb spectroscopy in combustion environments and under atmospheric conditions for fast and sensitive multispecies detection. We have demonstrated, for the first time, cavity-enhanced optical frequency comb spectroscopy in a flame, detected broadband high temperature H2O and OH spectra using the FTS in the near-infrared range and showed the potential of the technique for flame thermometry. For applications demanding a short measurement time and high sensitivity under atmospheric pressure conditions, we have implemented continuous-filtering Vernier spectroscopy, a dispersion-based spectroscopic technique, for the first time in the mid-infrared range. The spectrometer was sensitive, fast, robust, and capable of multispecies detection with 2 ppb detection limit for CH4 in 25 ms.

  • Public defence: 2017-06-02 13:15 Hörsal C, Samhällsvetarhuset, Umeå
    Stålnacke, Oscar
    Umeå University, Faculty of Social Sciences, Umeå School of Business and Economics (USBE), Business Administration.
    What do you expect?: individual investors' subjective expectations, information usage, and social interactions in financial decision-making2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis consists of an introductory part and four self-contained papers related to individual investors’ subjective expectations and their financial behavior. 

    Paper [I] analyzes multiple measures of individual investors’ expectations of risk and return using survey data on a random sample of individual investors in Sweden. The results indicate that, even though expectations from different measures are correlated, the magnitude of especially the risk expectations varies considerably between measures. The variations in the expectations mainly relate to differences in the responses to the questions underlying the different measures, rather than to the methods used to obtain them. Evaluation of the measures using three different comparisons indicates that the expectation measure proposed by Dominitz and Manski (2011) is the only measure for which it is possible to distinguish between individuals’ expectations using all of the considered comparisons.

    Paper [II] addresses the relationship between sophistication and the expectations of individual investors with respect to risk and return. The findings show that sophisticated investors have lower (higher) risk (return) expectations that are closer to objective measures than less sophisticated investors. These results are important, since they enhance the understanding of the underlying mechanisms through which sophistication could influence individuals’ financial decisions.

    Paper [III] provides new evidence for the sources of information individual investors’ use when making financial decisions and the relationship between how frequently investors use this information and their expectations of the risk and return in a stock market index, their confidence in these expectations, and their portfolio risk and return. The findings indicate that individual investors use different sources of filtered financial information (e.g., information packaged by a professional intermediary) more frequently than unfiltered financial information (e.g., information from annual reports and financial statements). However, an increase in the frequency with which investors use filtered financial information is positively related to their confidence in their stock-market expectations and to the risk in their stock portfolios. For investors who instead use unfiltered financial information more frequently than filtered financial information, the results indicate that they have more accurate stock-market expectations, lower portfolio risk, and higher portfolio return.

    Paper [IV] links individual investors’ financial risk-taking to the behavior of peers within their community. By using detailed data at the individual level, it is found that the risk-taking among peers affects individuals’ choice of portfolio risk. The results hold for the full sample of individuals concerning their choice of the overall proportion of risky assets and stock market participants’ choice of total and systematic stock-portfolio risk. Overall, the results stress that interaction with peers is an important channel through which individual risk-taking is affected.

  • Public defence: 2017-06-08 10:15 Humanisthuset, Hörsal F, Umeå
    Vingsle, Charlotta
    Umeå University, Faculty of Science and Technology, Department of Science and Mathematics Education. Umeå University, Faculty of Science and Technology, Umeå Mathematics Education Research Centre (UMERC).
    Formativ bedömning och självreglerat lärande: vad behöver vi för att få det att hända?2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Previous research has shown that substantial learning gains are possible when formative assessment and support for students’ development of self-regulated learning skills are implemented in classroom practice. Such implementation is not straightforward and there is a need for both further understanding of the knowledge and skills teachers require to practice formative assessment, and further insights into how different characteristics of ordinary teaching practices support students’ in becoming proficient self-regulated learners. This doctoral thesis includes a licentiate thesis and two articles. In the licentiate thesis, classroom observations are used to investigate the knowledge and skills used by a teacher engaged in a comprehensive formative classroom practice. The results show that the teacher's practice is complex and requires advanced knowledge and skills that are often used simultaneously and under time pressure. For example, the teacher, sometimes in a matter of seconds, handles new (to her) mathematics, makes inferences from students’ responses to their understanding, and based on these inferences makes decisions about her teaching. The first article is a literature review focusing on the effects of formative assessment on student achievement in mathematics since there is a lack of knowledge of the effects of formative assessment on student achievement, in particular for subject areas such as mathematics. In the review, a systematic literature search is made for articles studying the effects of both teacher-centered approaches and approaches emphasizing student involvement in the formative assessment processes. The latter type of approaches includes teacher practices that support students’ development of aspects of self-regulated learning competence. The results show that all approaches included in the review have significant positive effects on student achievement in mathematics. The second article examines in what ways learning situations in authentic classroom practices provide opportunities for the students to develop self-regulated learning skills, and how students experience these opportunities. The analysis is based on data from classroom observations of three teachers’ mathematics lessons, and on interviews with their students. The results show that instruction in self-regulated learning skills mostly occurred implicitly, and the opportunities to develop the skills were mainly provided and experienced at the observational level.

  • Public defence: 2017-06-08 13:00 Sal D, Umeå
    Skagerlind, Malin
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine. Umeå University, Faculty of Medicine, Department of Nursing.
    How to reduce the exposure to anticoagulants when performing haemodialysis in patients with a bleeding risk: a study of methods used in clinical practise2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    When a patient suffers from kidney failure and also has an enhanced risk of bleeding, the standard haemodialysis (HD) treatment becomes a problem. When human blood comes in contact with artificial material, as in the tubing system and in the dialyser (the extra corporeal circuit, ECC), the coagulation system is activated. If there is no increased risk of bleeding a bolus dose of anticoagulation is given intravenous to the patient before HD to avoid clotting. The most common anticoagulants used during HD are unfractionated heparin (UFH) and low molecule weight heparins (LMWH). Without anticoagulants there will be a total coagulation (clotting) of the blood in the ECC, an interrupted treatment and a blood loss of up to 300 ml for the patient. With an ongoing bleeding or an increased risk of bleeding in a patient that also needs HD, there are various alternatives that can be used to avoid or lower the need of anticoagulation. However, there is no golden standard, neither in Sweden or worldwide.

    The overall aim of this Thesis was to evaluate the safety and the efficacy of various models of anticoagulation that may be used in patients with a bleeding risk.

    The first study examined a low-dose anticoagulation model that was locally developed in Umeå, Sweden in the 1980s. The primary aim was to clarify to what extent this priming model was safe and efficient during intermittent HD for patients with a bleeding risk. Consecutive acute HD treatment protocols (248 procedures in 68 patients) were included. There were 178 patients with an increased bleeding risk who had their ECC (tubes, chambers and dialyser) flushed through (priming) with Heparin-Albumin-priming (HA-priming). There were 70 patients with no increased bleeding risk who received standard intermittent HD (priming with saline); these patients also received a bolus dose of anticoagulation intravenous before dialysis.

    The low-dose method entailed priming of the ECC with HA-priming with the intention to coat the surfaces with the solution and protect from blood to attach to it. Comparisons were made to dialysis in patients with no increased bleeding risk, who had received standard anticoagulation (SHD) with UFH or LMWH. The priming solutions were always discarded before HD was initiated. None or limited doses of UFH were added during the HD. There was no difference in extent of prematurely interrupted HA-primed dialysis compared to SHD (2.2 vs. 4.3%, p = 0.62). No secondary bleeding due to anticoagulation was reported in the protocols.

    Study 2 was performed to further clarify data in an extended group of acute intermittent HD using either HA-priming (885 treatments in 221 patients at risk of bleeding) or SHD (523 treatments in 100 patients with no bleeding risk who had received standard anticoagulation). In this extended study there was no difference in the extent of prematurely interrupted HA-dialysis (0.8%) compared to SHD (1%, p = 0.8). The results also showed less clotting for dialysers with a membrane area ≤ 1.7 m2. No secondary bleeding due to anticoagulation was reported in the protocols.

    Study 3 was an experimental in vitro study. The aim was to compare the anticoagulation effect of priming the ECC with different concentrations of albumin and/or heparin in saline. Priming with saline only was also evaluated. The priming fluids were always discarded after priming. Fresh whole blood from healthy human donors was used to perform in vitro dialyses in a recirculation system. The donated blood was equally divided into two bags, whereas one bag represented the control group and the other the intervention group. Priming with saline only and priming with albumin in saline resulted in rapid clotting of the blood in the ECC. These experiments indicated that HA-priming or priming with heparin in saline enabled fulfilment of all the in vitro dialyses.

    Study 4 was a clinical randomized cross-over study. The aim was to minimize the use of anticoagulant during HD in patients with a bleeding risk. Four different low-dose anticoagulation models were compared to SHD. Stable chronic HD patients participated in the study. The patients were their own controls. Aside from SHD, the four models of low-dose anticoagulation used were Heparin priming (H), HA-priming (HA), HA-priming in combination with a citrate containing dialysate (HAC), and a dialyser manufactured with a heparin-grafted membrane (Evodial®). The H-model was least suitable with 33 % interrupted treatments and the most extra doses of UFH needed. The HAC and Evodial® models were most preferable, both with an activated partial thromboplastin time (APTT) within references and with the least amounts of UFH needed. Evodial® had a lower urea reduction rate compared to the other models. HAC was the only model with no interrupted treatment. One patient suffered from a severe hypersensitivity reaction using Evodial®. No other side-effects were reported during the study.

    In conclusion an acute kidney injury is a life-threating situation that also includes patients with an increased bleeding risk and in need of HD for survival. If intermittent HD is the selected option, a priming of the ECC with a HA-solution in combination with a citrate containing dialysis fluid (HAC) is a safe and sufficient option for anticoagulation. Another option could be the heparin-grafted dialyser (Evodial®), although with a lower clearance coefficient and with a caution for a risk for hypersensitivity reaction or anaphylaxis.

    The full text will be freely available from 2018-03-31 00:00
  • Public defence: 2017-06-09 09:00 Bergasalen, byggnad 27, Norrlands universitetssjukhus, Umeå
    Brynolfsson, Patrik
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Applications of statistical methods in quantitative magnetic resonance imaging2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Magnetic resonance imaging, MRI, offers a vast range of imaging methods that can be employed in the characterization of tumors. MRI is generally used in a qualitative way, where radiologists interpret the images for e.g. diagnosis, follow ups, or assessment of treatment response. In the past decade, there has been an increasing interest for quantitative imaging, which give repeatable measurements of the anatomy. Quantitative imaging allows for objective analysis of the images, which are grounded in physical properties of the underlying tissues. The aim of this thesis was to improve quantitative measurements of Dynamic contrast enhanced MRI (DCE-MRI), and the texture analysis of diffusion weighted MRI (DW-MRI).

    DCE-MRI measures perfusion, which is the delivery of blood, oxygen and nutrients to the tissues. The exam involves continuously imaging the region of interest, e.g. a tumor, while injecting a contrast agent (CA) in the blood stream. By analyzing how fast and how much CA leaks out into the tissues, the cell density and the permeability of the capillaries can be estimated. Tumors often have an irregular and broken vasculature, and DCE-MRI can aid in tumor grading or treatment assessment. One step is crucial when performing DCE-MRI analysis, the quantification of CA in the tissue. The CA concentration is difficult to measure accurately due to uncertainties in the imaging, properties of the CA, and physiology of the patient. Paper I, the possibility of using two aspects of the MRI data, phase and magnitude, for improved CA quantification, is explored. We found that the combination of phase and magnitude information improved the CA quantification in regions with high CA concentration, and was more advantageous for high field strength scanners.

    DW-MRI measures the diffusion of water in and between cells, which reflects the cell density and structure of the tissue. The structure of a tumor can give insights into the prognosis of the disease. Tumors are heterogeneous, both genetically and in the distribution of cells, and tumors with high intratumoral heterogeneity have poorer prognosis. This heterogeneity can be measured using texture analysis. In 1973, Haralick et al. presented a texture analysis method using a gray level co-occurrence matrix, GLCM, to gauge the spatial distribution of gray levels in the image. This method of assessing texture in images has been successfully applied in many areas of research, from satellite images to medical applications. Texture analysis in treatment outcome assessment is studied in Paper II, where we showed that texture can distinguish between groups of patients with different survival times, in images acquired prior to treatment start.

    However, this type of texture analysis is not inherently quantitative in the way it is calculated today. This was studied in Paper III, where we investigated how texture features were affected by five parameters related to image acquisition and pre-processing. We found that the texture feature values were dependent on the choice of these imaging and preprocessing parameters. In Paper IV, a novel method for calculating Haralick texture features was presented, which makes the texture features asymptotically invariant to the size of the GLCM. This method allows for comparison of textures between images that have been analyzed in different ways.

    In conclusion, the work in this thesis has been aimed at improving quantitative analysis of tumors using MRI and texture analysis.

  • Public defence: 2017-06-09 10:00 Hörsal D, Samhällsvetarhuset
    Fjellfeldt, Maria
    Umeå University, Faculty of Social Sciences, Department of Social Work.
    Choice as governance in community mental health services2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    In 2009, the Act on Freedom of Choice Systems (SFS 2008:962) wasestablished in Sweden, and this enabled municipalities to organise services aschoice models. This thesis describes and analyses the implementation of afreedom of choice system within community mental health services. Daycentre services were in focus, and a case study was conducted of a majormunicipality that sought to be a “world-class city” in regard to citizens’ choice.The experiences of policy makers, managers, professionals, and participantswere explored in interviews, and documents on a national, municipal, and citydistrict level, as well as homepages of providers of community mental healthservices, were all part of the study and were analysed using content-analysismethods.

    The results showed that the freedom of choice system aimed for two objectives– improvements at the individual level and financial efficiency. In practice,financial efficiency was experienced as the main objective. Increased varietyof services was aimed for by the competitive model, but such variety was notobserved. Instead, services tended to be more similar than specialised.Concerning new providers, they were characterised as committedprofessionals running companies with strained economies. Participantsaffected by the reform expressed anxiety and worries due to theunpredictability and uncertainty embedded in the competitive choice model.Choice within the system concerned where to go, whereas participantsemphasised a wish to be able to influence the choice aspects of who carriedout the service and how much time to attend the services.

    The conclusion was that the freedom of choice system was implemented as atechnology of governance to increase financial efficiency of services.Individual choice was not experienced as increased in any aspect except forthe choice of where to go. Instead, freedom of choice actually appeared todecrease due to standardisation and hierarchical structures. Aspects that werefound to be relevant when designing freedom of choice systems aiming toincrease individual freedom of choice were to address predictability andcontinuity, to address sustainable financial premises, to analyse the predictedimpact of administrative systems that are to be used, and to avoid the use of“hidden goals” in the policy-making process.

  • Public defence: 2017-06-09 10:00 Stora hörsalen, KBE303, KBC-huset, Umeå
    Li, Yaozong
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Understanding molecular mechanisms of protein tyrosine kinases by molecular dynamics and free energy calculations2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Background: Insulin receptor kinase (IRK) and Insulin-like growth factor 1 receptor kinase (IGF-1RK) are two important members in the large class of tyrosine kinase receptors. They play pivotalroles in the regulation of glucose homeostasis, cell proliferation, differentiation, motility, andtransformation. Their dysfunctions are linked to diabetes, rheumatoid arthritis and many cancers.Although their regulatory mechanisms have been widely studied experimentally, the atomisticdetails are still poorly understood, especially for the influences caused by activation loop (A-loop)phosphorylation.Methods: Molecular dynamics (MD) and alchemical free energy simulations are carried out tounderstand mechanisms underlying the kinase proteins regulation and their thermodynamic basis.To capture a full picture about the entire kinase catalytic cycle, different functional steps areconsidered, i.e., conformational transition, substrate binding, phosphoryl transfer and productrelease. The effects of the A-loop phosphorylation on protein’s dynamics, structure, stability, andfree energy landscape are examined by various analysis methods, including principle componentanalysis (PCA), motion projection, dynamical network analysis and free energy perturbation.Results: The main findings are: 1) A-loop phosphorylation shifts the kinase conformationalpopulation to the active one by changing the electrostatic environments in the kinase apo form, 2)allosterically fine-tunes the orientation of the catalytic residues mediated by the >C-helix in thereactant and product binding states, and 3) thermodynamically favors the kinase catalysis presentedby a catalytic-cycle-mimic free energy landscape. An integrated view on the roles of A-loopphosphorylation in kinase allostery is developed by incorporating kinase’s dynamics, structuralinteractions, thermodynamics and free energy landscape. In addition, new soft-core potentials(Gaussian soft-core) and protocols are developed to conduct accurate and efficient alchemical freeenergy calculations.Conclusions: The entire catalytic cycle is examined by MD and free energy calculations andcomprehensive analyses are conducted. The findings from the studied kinases are general and canbe implemented to the other members in IRK family or even to more non-homologous familiesbecause of the conservation of the characteristic residues between their A-loop and >C-helix. Inaddition, the Gaussian soft-core potentials provide a new tool to perform alchemical free energycalculations in an efficient way.

  • Public defence: 2017-06-09 10:00 Hörsal 1031, Norra Beteendevetarhuset, Umeå
    Rassokhina, Elena
    Umeå University, Faculty of Arts, Department of language studies.
    Shakespeare's sonnets in Russian: the challenge of translation2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Shakespeare’s 154 sonnets have become the interest of several generations of Russian translators. Overall, after their first appearance in the middle of the nineteenth century, at least thirty-five Russian translations of the complete sonnet collection have been produced so far, though mostly during the last three decades. The overall objective of the present thesis is to examine the evolution of Russian translations of Shakespeare’s sonnets over the years. The thesis is novel in that it offers an analysis of specific linguistic, literary and cultural challenges the numerous Russian translators have dealt with while translating the sonnets, as well as the strategies adopted in an effort to resolve them.

    In order to achieve the study objectives, several individual sonnets and a number of their Russian translations have been selected as a sample representing challenging areas that have been more closely investigated in four articles. The method of cross comparison has been applied throughout the study. Both the introductory part and the articles address certain problematic translation issues, such as the sonnets’ formal structure, the pronouns of address, grammatical gender, bawdy language, sexual puns, culture-specific items, and metaphors.

    The results provide evidence for seeing translation as a multi-layered and ever-changing process, which, apart from the pure linguistic tasks, combines historical, political and ideological aspects. The findings of the study suggest that translation competence, namely deep understanding of the context and its fundamental cultural and social features, motivates the translator’s interpretation of the contradictions and uncertainties of Shakespeare’s poems. Those include the sonnets genre, relation to Shakespeare’s biography, the order of the poems in the first 1609 Quarto. The analysis also identifies the ways in which the target language’s social and historical context have had an impact on the choices made by the translators.

    On the whole, the study’s results do not contradict Mikhail Gasparov’s model describing the pendulum-like movement from “free” to “literal” approaches through the history of Russian literary translation.  

  • Public defence: 2017-06-09 10:15 Hörsal F, Humanisthuset, Umeå universitet, Umeå
    Boström, Erika
    Umeå University, Faculty of Science and Technology, Department of Science and Mathematics Education. Umeå University, Faculty of Science and Technology, Umeå Mathematics Education Research Centre (UMERC).
    Formativ bedömning: en enkel match eller en svår utmaning? Effekter av en kompetensutvecklingssatsning på lärarnas praktik och på elevernas prestationer i matematik2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Research reviews have shown that the use of formative assessment in classroom practice can substantially improve student achievement. However, a strong research base about how to support teachers’ implementation of such formative classroom practice is lacking. In this thesis, I investigate the effects of a comprehensive professional development programme (PDP) in formative assessment on teachers’ classroom practice and students’ achievement in mathematics. In addition, I identify reasons for the changes made in the teachers’ formative classroom practice. Fourteen randomly selected year - 7 mathematics teachers participated in the PDP. The teachers’ formative classroom practice before and after attending the programme was analysed and described, and reasons for their change in practice were explored. The effect of the changes in formative classroom practice on students’ mathematics achievement was examined using pre- and post-tests administered to both the intervention group and a control group. A mixed methods approach with classroom observations, teacher interviews, questionnaires and student achievement tests in mathematics was used in the studies included in the thesis.

    The results show that the teachers used aspects of formative assessment in their classroom practice before the PDP, but that there was plenty of room for development towards a more effective formative assessment practice. Several possibilities for developing the practice were identified. After the PDP the teachers believed in the idea of formative assessment and were motivated to make changes towards a more formative classroom practice. The teachers included new formative assessment activities in their classroom practice, but in different ways and to different degrees. The characteristics of these changes were identified, and also the characteristics of the PDP that the teachers found to be influential for their development of the formative classroom practice. Results also show that the teachers’ motivational beliefs held after the PDP was an explanatory factor for their changes in practice. However, the formative assessment practice the teachers implemented did not have a significant effect on their students’ achievement compared to the control group. In addition, there was no correlation between the number of formative assessment activities implemented by the teachers and their students’ achievement gains. Reasons for these non-effects on student achievement, and for the teachers’ degree and type of implementation of formative assessment in the classroom practice, are discussed in the thesis.

  • Public defence: 2017-06-09 13:00 Lilla Hörsalen, KBC huset, Umeå
    Klaus, Marcus
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Land use effects on greenhouse gas emissions from boreal inland waters2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Anthropogenic activities perturb the global carbon and nitrogen cycle with large implications for the earth’s climate. Land use activities deliver excess carbon and nitrogen to aquatic ecosystems. In the boreal biome, this is mainly due to forestry and atmospheric deposition. Yet, impacts of these anthropogenically mediated inputs of carbon and nitrogen on the processing and emissions of greenhouse gases from recipient streams and lakes are largely unknown. Understanding the ecosystem-scale response of aquatic greenhouse gas cycling to land use activities is critical to better predict anthropogenic effects on the global climate system and design more efficient climate change mitigation measures.

    This thesis assesses the effects of forest clearcutting and nitrate enrichment on greenhouse gas emissions from boreal inland waters. It also advances methods to quantify sources and sinks of these emissions. Short-term clearcut and nitrate enrichment effects were assessed using two whole-ecosystem experiments, carried out over four years in nine headwater catchments in boreal Sweden. In these experiments, I measured or modeled air-water fluxes of carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O), combining concentration, ebullition and gas-transfer velocity measurements in groundwater, streams and lakes. By using Swedish national monitoring data, I also assessed broad-scale effects of forest clearcutting by relating CO2 concentrations in 439 forest lakes to the areal proportion of catchment forest clearcuts. To improve quantifications of CO2 sources and sinks in lakes, I analyzed time series of oxygen concentrations and water temperature in five lakes on conditions under which whole-lake metabolism estimates can be inferred from oxygen dynamics given the perturbing influence of atmospheric exchange, mixing and internal waves.

    The experiments revealed that aquatic greenhouse gas emissions did not respond to nitrate addition or forest clearcutting. Importantly, riparian zones likely buffered clearcut-induced increases in groundwater CO2 and CH4 concentrations. Experimental results were confirmed by monitoring data showing no relationship between CO2 patterns across Swedish lakes and clearcut gradients. Yet, conclusions on internal vs. external CO2 controls largely depended on whether spatially or temporally resolved data was used. Partitioning CO2 sources and sinks in lakes using time series of oxygen was greatly challenged by physical transport and mixing processes.

    Conclusively, ongoing land use activities in the boreal zone are unlikely to have major effect on headwater greenhouse gas emissions. Yet, system- and scale specific effects cannot be excluded. To reveal these effects, there is a large need of improved methods and design of monitoring programs that account for the large spatial and temporal variability in greenhouse gas dynamics and its controls by abiotic and biotic factors.

  • Public defence: 2017-06-12 09:00 Hörsal D, Umeå
    D'Ascenzi, Flavio
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine.
    Atrial function and loading conditions in athletes2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Intensive training is associated with hemodynamic changes that typically induce an enlargement of cardiac chamber. Despite LA dilatation in athletes has been interpreted as a benign adaptation, little evidence is available. The aim of this thesis is to demonstrate that LA size changes in response to alterations in loading conditions and to analyse atrial myocardial function in athletes through the application of novel echocardiographic techniques.

    We found that top-level athletes exhibit a dynamic morphological and functional LA remodelling, induced by training, with an increase in reservoir and conduit volumes, but stable active volume. Training causes an increase in biatrial volumes which is accompanied by normal filling pressures and stiffness. These changes in atrial morphology are not associated with respective electrical changes. Extending the evidence from adult athletes to children, we found that training-induced atrial remodelling can occur in the early phases of the sports career and is associated with a preserved biatrial function. Finally, in a meta-analysis study of the available evidence we demonstrated that atrial function and size are not affected by aging.

    In conclusions, athlete’s heart is characterized by a physiological biatrial enlargement. This adaptation occurs in close association with LV cavity enlargement, is dynamic and reversible. This increase in biatrial size is not intrinsically an expression of atrial dysfunction. Indeed, in athletes the atria are characterized by a preserved reservoir function, normal myocardial stiffness, and dynamic changes in response to different loading conditions.

  • Public defence: 2017-06-13 13:00 N360, Umeå
    Areljung, Sofie
    Umeå University, Faculty of Science and Technology, Department of Science and Mathematics Education. Umeå University, Faculty of Social Sciences, Umeå Centre for Gender Studies (UCGS).
    Utanför experimentlådan: kunskapsproduktion, tid och materia i förskolans naturvetenskapsundervisning2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The aim of this thesis is to contribute knowledge on conditions for science teaching in preschool. While Swedish preschool practices commonly build on children’s subjective experiences, scientific knowledge production is often associated with objectivity and detachedness. Seen from that perspective, tensions may occur when the knowledge cultures of preschool and science meet, as when science teaching is implemented in preschool. This thesis seeks to explore issues that are crucial for teachers to negotiate when they implement science teaching in preschool.

    The thesis includes five articles that build on empirical data in the form of teachers’ talk (interviews, focus group discussion, project meetings) and observation data from preschool practice. The data analyses draw on various theoretical perspectives, including communities of practice and feminist critique of science as well as theoretical concepts connected to framing and agential realism.

    The main result is that it is crucial, to teachers’ implementation of science teaching in preschool, that science content is open to children’s contributions. Further, the results show that teachers integrate several different forms of knowledge production when working with science content in practice. For example, observations and systematic investigations are combined with imagination and children’s bodily experiences. This goes against the presumed tensions between the knowledge cultures of preschool and science. However, tensions between the knowledge cultures are indicated by teachers’ unwillingness to interfere with children’s investigative processes or ideas about science content by relating children’s ideas to scientific explanatory models. Seen from a teacher’s perspective, it appears to be unproblematic to leave children’s ideas about science content unresolved, compared to leaving children’s ideas about social relations and other content unresolved.

    Drawing on the results, I discuss teaching beyond the limited material and temporal dimensions of the science box, which emerges as a metaphor when teachers describe a way of teaching that they are not comfortable with. Further, I suggest that the concept working theories, which addresses children’s tentative ideas about relations in their surrounding world, be introduced in preschool science teaching, to ease the perceived conflict between children’s ideas about science and scientific explanatory models.

  • Public defence: 2017-06-15 10:00 KB3A9, KBC, Umeå
    Maier, Dominique Béatrice
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Combining limnology and paleolimnology: a refined understanding of environmental sediment signal formation in a varved lake2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Paleoclimatic archives, such as lake sediments, extend our understanding of terrestrial and aquatic ecosystem dynamics in relation to climate variability beyond the period covered by instrumental data. In this context, annually laminated (i.e. varved) lake sediments are particularly valuable, as they offer high temporal resolution and undisturbed sediment. However, in order to extract reliable climate information from lake sediments, a careful calibration with the processes controlling the sediment formation is essential. This thesis combines limnological and paleolimnological data from a varved, boreal lake in northern Sweden (Nylandssjön, Nordingrå) collected over different time scales. The main aim of the thesis is to gain a more refined insight into which processes are reflected in the sedimentary diatom assemblage. More specifically, sequential sediment trap records were coupled with physical, chemical and biological lake monitoring and environmental data for comparison and validation with the varved sediment record. The main result of the thesis is that timing, succession and inter-annual variability of key limnological and environmental processes (e.g. ice-cover duration, lake over-turn or catchment run-off) are of major importance for the sedimentary diatom assemblage formation. Continuous monitoring of physico-chemical parameters over three consecutive years identified varying winter air temperature as a major factor influencing in-lake processes and hence the diatom record. Timing of lake over-turn and catchment run-off seemed to be the driver for monospecific diatom blooms, which are reflected in the annual sediment signal. The integrated annual diatom signal in the sediment was dominated by spring or autumn blooms, resulting either from a Cyclotella glomerata dominated spring bloom after relatively warm winter conditions, or a Asterionella formosa dominated autumn bloom after relatively cold winter conditions. The analysis of the diatom stratigraphy in the varved sediment over several decades corroborated the importance of climatic variables (late winter air temperature and NAO), even though the variables with the most predictive power for variance in the diatom data were associated with sediment composition (C, N and sedimentation rate) and pollution (Pb and Cu). Overall, the analysis of the drivers of inter-annual and decadal diatom assemblage fluctuations emphasizes the importance of winter air temperature, indicating that weather extremes may be disproportionately represented in annual sediment records in contrast to nutrient concentrations or sedimentation rate.

  • Public defence: 2017-06-16 13:00 Hörsal E, humansithuset, Umeå
    Lundmark, Mikael
    Umeå University, Faculty of Arts, Department of historical, philosophical and religious studies.
    Religiositet och coping: religionspsykologiska studier av kristna med cancer2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis investigates the interdependence of religiosity and a life situation changed by cancer, focusing especially on the coping process. This implies analyses of a number of identified expressions of religiosity regarding prerequisites and functions in the coping process. In order to synthesize the results from the studies, the aim has been operationalized into three comprehensive research questions that were posed to each of the empirical studies of the thesis: 1) What are the functions of the analysed expressions of religiosity during the coping process? 2) What prerequisites for the influence of religiosity on the coping process can be identified?  3) How is religiosity influenced by a life situation changed by cancer? The empirical studies are presented in four separate articles. Each of the studies has its own specific research questions that are related to the comprehensive research questions. The method was qualitative and explorative. The research material was gathered with qualitative interviews of 20 Swedish informants of varying gender, age, congregational affiliation and diagnosis. The informants defined themselves as Christians and practised their Christian faith and had or had had a cancer disease. There is longitudinal data from half of the group. The theoretical framework was based on the coping theories developed by Kenneth Pargament and Ruard Ganzevoort and complemented by, among other things, the object-relations theoretical concept of transitional objects.

    The results show that most of the analysed expressions of religiosity function as a preserving coping method but some of them also function as a reconstructing coping method. In some cases, the expressions of religiosity also function as methods of attributing control, either to God or to the individual. Two main groups of prerequisites for the expressions of religiosity were identified in conjunction with the coping process: contextual and psychological. The former could in turn be divided into religious and medical contexts; the latter into several different kinds, such as perceptual psychological factors, the need to create and use transitional objects, locus of control, and personality traits. Reconstructing coping methods imply varying degrees of changes in the informants’ religiosity, both regarding the analysed expression of religiosity and other expressions of religiosity. In addition to gaining insights into the interdependence of religion and coping for Christians living with cancer, the study contributes to the development of the psychology of religion coping theory by adding to the theory: 1) suggested specifications to the current concepts of Pargament’s coping theory; 2) the concept coping tool; 3) the distinction between functional and relational regarding the concepts of coping mechanism and coping method; 4) the coping mechanism attributing, and 5) the distinction between unilateral and bilateral deferring coping styles. The results indicate that the coping process can include a creative element in the form of a search for, or creation of, functional coping methods and/or coping tools which enhance the functionality of the coping process.