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  • Public defence: 2017-06-30 10:00 Magnéli Hall, Arrhenius Laboratory, Stockholm
    González Miera, Greco
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Homogeneous and heterogeneous Cp*Ir(III) catalytic systems: Mechanistic studies of redox processes catalyzed by bifunctional iridium complexes, and synthesis of iridium-functionalized MOFs2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The purpose of this doctoral thesis is to investigate and develop catalytic processes mediated by iridium(III) complexes. By understanding the mechanisms, the weaknesses of the designed catalysts can be identified and be overcome in the following generation.

    The thesis is composed of two general sections dedicated to the synthesis and applications of homogeneous catalysts and to the preparation of heterogeneous catalysts based on metal-organic frameworks (MOFs). After a general introduction (Chapter 1), the first part of the thesis (Chapters 2-4, and Appendix 1) covers the use of several homogeneous bifunctional [Cp*Ir(III)] catalysts in a variety of chemical transformations, as well as mechanistic studies.

    Chapter 2 summarizes the studies on the N-alkylation of anilines with benzyl alcohols catalyzed by bifunctional Ir(III) complexes. Mechanistic investigations when the reactions were catalyzed by Ir(III) complexes with a hydroxy-functionalized N-heterocyclic carbene (NHC) ligand are discussed, followed by the design of a new generation of catalysts. The chapter finishes presenting the improved catalytic performance of these new complexes.   

    A family of these NHC-iridium complexes was evaluated in the acceptorless dehydrogenation of alcohols, as shown in Chapter 3. The beneficial effect of a co-solvent was investigated too. Under these base-free conditions, a wide scope of alcohols was efficiently dehydrogenated in excellent yields. The unexpected higher activity of the hydroxy-containing bifunctional NHC-Ir(III) catalysts, in comparison to that of the amino-functionalized one, was investigated experimentally.

    In the fourth chapter, the catalytic process presented in Chapter 3 was further explored on 1,4- and 1,5-diols, which were transformed into their corresponding tetrahydrofurans and dihydropyrans, respectively. Mechanistic investigations are also discussed.

    In the second part of the thesis (Chapter 5), a Cp*Ir(III) complex was immobilized into a MOF. The heterogenization of the metal complex was achieved efficiently, reaching high ratios of functionalization. However, a change in the topology of the MOF was observed. In this chapter, the use of advanced characterization techniques such as X-ray absorption spectroscopy (XAS) and pair distribution function (PDF) analyses enabled to study a phase transformation in these materials.

  • Public defence: 2017-08-18 10:00 hörsal 11, hus F, Stockholm
    Berlin, Martin
    Stockholm University, Faculty of Social Sciences, Department of Economics.
    Essays on the Determinants and Measurement of Subjective Well-Being2017Doctoral thesis, monograph (Other academic)
    Abstract [en]

    This thesis consists of four self-contained essays in economics, all concerned with different aspects of subjective well-being. The abstracts of the four studies are as follows.

    Beyond Income: The Importance for Life Satisfaction of Having Access to a Cash Margin. We study how life satisfaction among adult Swedes is influenced by having access to a cash margin, i.e. a moderate amount of money that could be acquired on short notice either through own savings, by loan from family or friends, or by other means. We find that cash margin is a strong and robust predictor of life satisfaction, also when controlling for individual fixed effects and socio-economic conditions, including income.

    Decomposing Variation in Daily Feelings: The Role of Time Use and Individual Characteristics. I explore the potential of using time-use data for understanding variation in affective well-being. Using the Princeton Affect and Time Survey, I decompose variation in daily affect into explained and unexplained within- and between person variation. Time use is found to mostly account for within-variation. Hence, its explanatory power is largely additive to that of individual characteristics. The explanatory power of time use is small, however. Activities only account for 1–7% of the total variation and this is not increased much by adding contextual variables.

    The Association Between Life Satisfaction and Affective Well-Being. We estimate the correlation between life satisfaction and affect — two conceptually distinct dimensions of subjective well-being. We propose a simple model that distinguishes between a stable and a transitory component of affect, and which also accounts for measurement error in self-reports of both variables, including current-mood bias effects on life satisfaction judgments. The model is estimated using momentarily measured well-being data, from an experience sampling survey that we conducted on a population sample of Swedes aged 18–50 (n=252). Our main estimates of the correlation between life satisfaction and long-run affective well-being range between 0.78 and 0.91, indicating a stronger convergence between these variables than many previous studies that do not account for measurement issues.

    Do OLS and Ordinal Happiness Regressions Yield Different Results? A Quantitative Assessment. Self-reported subjective well-being scores are often viewed as ordinal variables, but the conventional wisdom has it that OLS and ordered regression models (e.g. ordered probit) produce similar results when applied to such data. This claim has rarely been assessed formally, however, in particular with respect to quantifying the differences. I shed light on this issue by comparing the results from OLS and different ordered regression models, in terms of both statistical and economic significance, and across data sets with different response scales for measuring life satisfaction. The results are mixed. The differences between OLS, probit and logit estimates are typically small when the response scale has few categories, but larger, though not huge, when an 11-point scale is used. Moreover, when the error term is assumed to follow a skewed distribution, larger discrepancies are found throughout. I find a similar pattern in simulations, in which I assess how different methods perform with respect to the true parameters of interest, rather than to each other.

  • Public defence: 2017-08-25 10:00 Aula Svea, Socialhögskolan, Stockholm
    Manhica, Hélio
    Stockholm University, Faculty of Social Sciences, Centre for Health Equity Studies (CHESS).
    Mental health, substance misuse and labour market participation in teenage refugees in Sweden – A longitudinal perspective2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Aim: To fill the knowledge gap about the importance of contextual factors after resettlement on mental health, substance misuse and labour market participation among young refugees who immigrate to Sweden as teenagers. Methods: Register studies in national registers of national cohorts of young refugees, unaccompanied and accompanied, who settled in Sweden as teenagers. Studies 1-4 used Cox regression models to study the risks of psychiatric care consumption and substance misuse, while Study 5 used multinomial regression to study position on the labour. These findings were compared with peers from the same birth cohorts in the general Swedish population and non-European intercountry adoptees (Studies 2 and 5). Results: The overall results suggest that young accompanied and unaccompanied refugees were more likely to be admitted to psychiatric inpatient and compulsory hospital care, but not outpatient care, with refugees born in the Horn of Africa and Iran having the highest risk (Study 1). Young accompanied and unaccompanied refugees also had higher risk of hospitalization and criminal conviction associated with substance misuse (Study 3). Longer duration of residence in Sweden was associated with increased risks of outpatient care (Study 1) and hospitalization related to substance misuse (studies 3 and 4). These increase risks of young refugees were associated with their socioeconomic living conditions (Studies 3 and 4), but risk factors associated with the country of origin of the refugee population and the intercountry adoptees were more important determinants of schizophrenia than socioeconomic conditions in Sweden (Study 2). Young accompanied and unaccompanied refugees and intercountry adoptees had a lower likelihood of being in full employment than native Swedes with comparable levels of education. Secondary education, however, increased employment chances and reduced the risk of being neither employed nor in education or training (Study 5). Conclusion: Evidence suggests that several groups of young refugees are at higher risk of mental health problems and substance misuse. They also face employment disadvantages and barriers to psychiatric care in the early stages of developing a psychiatric disorder.

  • Public defence: 2017-09-01 10:00 Nordenskiöldsalen, Geovetenskapens hus, Stockholm
    Giovanoulis, Georgios
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    What contributes to human body burdens of phthalate esters?: An experimental approach2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Phthalate esters (PEs) and alternative plasticizers used as additives in numerous consumer products are continuously released into the environment leading to subsequent human exposure. The ubiquitous presence and potential adverse health effects (e.g. endocrine disruption and reproductive toxicity) of some PEs are responsible for their bans or restrictions. This has led to increasing use of alternative plasticizers, especially cyclohexane-1,2-dicarboxylic acid diisononyl ester (DINCH). Human exposure data on alternative plasticizers are lacking and clear evidence for human exposure has previously only been found for di(2-ethylhexyl) terephthalate (DEHTP) and DINCH, with increasing trends in body burdens. In this thesis, a study population of 61 adults (age: 20–66; gender: 16 males and 45 females) living in the Oslo area (Norway) was studied for their exposure to plasticizers. Information on sociodemographic and lifestyle characteristics that potentially affect the concentrations of PE and DINCH metabolites in adults was collected by questionnaires. Using the human biomonitoring approach, we evaluated the internal exposure to PEs and DINCH by measuring concentrations of their metabolites in urine (where metabolism and excretion are well understood) and using these data to back-calculate daily intakes. Metabolite levels in finger nails were also determined. Since reference standards of human metabolites for other important alternative plasticizers apart from DINCH (e.g. DEHTP, di(2-propylheptyl) phthalate (DPHP), di(2-ethylhexyl) adipate (DEHA) and acetyl tributyl citrate (ATBC)) are not commercially available, we further investigated the urine and finger nail samples by Q Exactive Orbitrap LC-MS to identify specific metabolites, which can be used as appropriate biomarkers of human exposure. Many metabolites of alternative plasticizers that were present in in vitro extracts were further identified in vivo in urine and finger nail samples. Hence, we concluded that in vitro assays can reliably mimic the in vivo processes. Also, finger nails may be a useful non-invasive matrix for human biomonitoring of specific organic contaminants, but further validation is needed. Concentrations of PEs and DINCH were also measured in duplicate diet, air, dust and hand wipes. External exposure, estimated based on dietary intake, air inhalation, dust ingestion and dermal uptake, was higher or equal to the back-calculated internal intake. By comparing these, we were able to explain the relative importance of different exposure pathways for the Norwegian study population. Dietary intake was the predominant exposure route for all analyzed substances. Inhalation was important only for lower molecular weight PEs, while dust ingestion was important for higher molecular weight PEs and DINCH. Dermal uptake based on hand wipes was much lower than the total dermal uptake calculated via air, dust and personal care products, but still several research gaps remain for this exposure pathway. Based on calculated intakes, the exposure risk for the Norwegian participants to the PEs and DINCH did not exceed the established tolerable daily intake and reference doses, and the cumulative risk assessment for combined exposure to plasticizers with similar toxic endpoints indicated no health concerns for the selected population. Nevertheless, exposure to alternative plasticizers, such as DPHP and DINCH, is expected to increase in the future and continuous monitoring is required. Findings through uni- and multivariate analysis suggested that age, smoking, use of personal care products and many other everyday habits, such as washing hands or eating food from plastic packages are possible contributors to plasticizer exposure.

  • Public defence: 2017-09-01 10:00 De Geersalen, Geovetenskapens hus, Stockholm
    Stymne, Anna-Carin
    Stockholm University, Faculty of Humanities, Department of History.
    Hur begriplig är historien?: Elevers möjligheter och svårigheter i historieundervisningen i skolan2017Doctoral thesis, monograph (Other academic)
    Abstract [en]

    The thesis focuses on how students learn history in the classroom, more precisely on their possibilities and difficulties in developing competence in the school subject of history. There is a particular emphasis on how they explain and understand historical processes and concepts within the subject of history. Participants are students of different grades, 8–19 years old. The purpose of the study is to explore how students learn history in concrete learning situations and my focus is on the types of knowledge students understand, learn, develop and use in comparison with what they are expected to learn.  This is done based on three fundamental and well-established principles of learning. To examine what kinds of knowledge students need I use three main types of knowledge: declarative content knowledge (facts and concepts), procedural knowledge (knowledge about how to do things) and self-regulatory knowledge (knowledge about how to regulate our memory, thought and learning). I also use concepts and insights from systemic functional linguistics (SFL) in order to explain why the students use language and communicate the way they do.

    The thesis shows that history is challenging for young students. Young students have difficulties with complex and abstract concepts in history as they treat concepts as facts. Older, more competent, students use concepts on a more abstract level and use different kinds of linguistic resources when formulating explanations of higher complexity, more similar to the way explanations in the domain of history are commonly written. The youngest students and some of the older students lacked factual knowledge, concept knowledge, domain specific self-regulatory knowledge and linguistic resources.

    Declarative content knowledge and facts are more important and more difficult for young students to understand, develop, organize and learn than previous scholars have shown empirically. Students’ abilities to understand facts and ideas in the context of a conceptual framework and to organize and structure facts with the help of concepts at different level of abstraction (conceptual understanding) are crucial. Students also need linguistic resources, both lexical knowledge and knowledge of text structures. Language is crucial both in the process of acquiring knowledge and in the process of communication. In the learning process, teaching is crucial, since individual students’ potential to develop competence depend on the potential of the teacher to discover and engage their preconceptions and arrange for learning in a way that give students the kind of knowledge they need.