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  • Public defence: 2018-11-13 13:00 sal E306, Arrheniuslaboratorierna, Stockholm
    Martins, António
    Stockholm University, Faculty of Science, Department of Molecular Biosciences, The Wenner-Gren Institute.
    The cell biology and catalytic properties of the nutrient-induced signaling endoprotease Ssy52018Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Cells continuously sense and respond to changes in the presence, quality and quantity of external and internal nutrients. Specific signaling proteases have been identified based on their roles in processing or destruction of distinct sets of downstream effector proteins in response to environmental cues. The Saccharomyces cerevisiae Ssy5 signaling endoprotease has a key role in regulating central metabolism, cellular aging, and morphological transitions important for growth and survival. Ssy5 is a core component of the Ssy1–Ptr3-Ssy5 (SPS) sensor, which enables yeast cells to respond to extracellular amino acids and induce their uptake. Ssy5 cleaves transcription factors Stp1 and Stp2, permitting their translocation to the nucleus where they enhance the expression of amino acid permease genes. This thesis focuses on Ssy5, its biogenesis and catalytic properties (paper I), the spatial determinants underlying Ssy5 function in SPS-sensor context (paper II) and substrate cleavage (paper III).

    Ssy5 is comprised of pro- and catalytic-(Cat)-domains. The Cat-domain possesses characteristic hallmarks of a serine protease; however, serine protease-specific inhibitors have limited effect, confounding its classification. In paper I we unambiguously show that Ssy5 is a serine protease, define the precise sites of cleavage in Stp1 and Stp2, and describe the sequence specific requirements of their cleavage. The uniquely large prodomain (381 amino acids) has two essential functions. Initially, it is required in cis for the maturation of the Cat-domain, helping to overcome a folding barrier that is reflected in the high stability of the Cat-domain. Subsequent to attaining enzymatic competence, Ssy5 undergoes an autolytic cleavage event. The domains remain associated and the prodomain functions to fetter the proteolytic activity of the Cat-domain.

    The plasma membrane (PM) localization of Ssy1 has recently been questioned in a report that postulated that Ssy1 is a component of the endoplasmic reticulum (ER) and contributes to the formation of ER-PM junctions. In paper II, using mutational and subcellular fractionation experiments we critically examined this notion that is inconsistent with the current understanding of Ssy5 activation, i.e., the unfettering of the Cat-domain occurs in strict association with Ssy1 at the PM. The data show that Ssy1 is indeed a PM protein, and importantly, Ssy5-activation occurs independent of ER-PM junctions. A di-acidic ER exit motif was identified that is critical for proper PM localization and function of Ssy1. In paper III, we report that the Cat-domain is post-translationally modified in a manner dependent on Ptr3 and the PM casein kinase I (Yck1/2), consistent with Ssy5 activation occurring at the PM. Strikingly, the activated Cat-domain is capable of properly cleaving Stp1 fused to an ER membrane protein. The amino acid-induced cleavage of this artificial membrane-bound substrate occurs in a Δtether strain (ist2Δ scs2Δ scs22Δ tcb1Δ tcb2Δ tcb3Δ) lacking ER-PM junctions. These findings indicate that the activated Cat-domain can bind and functionally interact with substrates distant from the PM. Finally, we show that the Cat-domain is degraded faster in amino acid-induced cells. These findings provide novel insights into the SPS-sensing pathway and demonstrate for the first time that the resetting of the SPS-sensing system correlates with Cat-domain degradation.

  • Public defence: 2018-11-15 10:00 Vivi Täckholmsalen (Q-salen), NPQ-Huset, Stockholm
    Hebinck, Aniek
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Shaping sustainable food systems: Local participation in addressing global challenges2018Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The current unsustainable trajectory of food systems puts the social and ecological processes and functions on which human flourishing depends at risk. This last decade has seen, on one hand, continued insistence on transformative action and on the other, uncertainty and instability with respect to traditional, established institutions, such as the state. As a response, new configurations of actors are aiming to participate in food system governance. New governance arrangements that increasingly lean on civic actors are considered as windows of opportunity, but their possible pitfalls have received less attention. This thesis seeks to understand and explain how the participation of new actors in the food system contributes to transformative change towards sustainable food systems. In order to achieve this, this thesis develops and applies a novel interdisciplinary approach, which combines: a food systems perspective, theories concerning food system governance, transformation, participation and the creation of transformative futures.

    The four papers each investigate essential elements for transformative change towards sustainable food systems. Each paper represents different empirical cases, but the papers’ theories build on each other. Paper I starts by setting out a transdisciplinary understanding of food systems in terms of structure and dynamics beyond existing frameworks, built on co-design through a science-policy dialogue. It unpacks the idea of sustainable food systems across four elements: nutrition and diet, economic impacts, environmental impacts, and social equity. Paper II explores food systems change, through the case of food banks in Europe; civil initiatives that address food poverty by handing out surplus food parcels. By comparing initiatives from the Netherlands, Italy and Ireland, their transformative impact on food systems is reviewed. Paper III goes on to interrogate the role of participation in change processes. It does this through an assessment of the extent to which participation is properly executed in policy processes that aim to democratise and ‘open-up’ the making of an Urban Food Strategy. It does so by comparing the case of Eindhoven, the Netherlands and Exeter, United Kingdom. Finally, paper IV is focused on how imagined futures affect participatory change processes. It focuses on the use of future-oriented participatory methods, foresight, and their implications for transformative change. The paper contributes to the field of foresight by formulating several levels of ambition for transformative change associated with foresight processes, and a number of different roles for the researcher to take in processes of change. 

    The papers establish a new understanding of food systems, followed by insights into food systems change, the role of participation in change processes, and how imagined futures affect this participation. Together, they demonstrate the benefits of buildingon food system knowledges from, from different spheres – i.e. public, private and civil as well as across different scientific research disciplines. The thesis concludes that a concrete, actionable understanding of how participatory processes focused on present and future food systems, contribute to transformative change in food systems.

  • Public defence: 2018-11-16 10:00 Magnélisalen, Kemiska övningslaboratoriet, Stockholm
    Colas, Kilian
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    New C-C coupling Reactions Enabled by Main-group Organometallics2018Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The carbon-carbon bond has always been at the very core of chemical research. Strategies for the creation of C−C bonds are one of the keys to the construction game that organic chemists play with the building blocks provided by Nature, with the ultimate goal of producing useful molecular structures that will serve society as medicines, materials, imaging tools, catalysts, and ligands (to mention but a few). While very different in their structure, all of these molecules are often prepared by the same methods. However, efficiency could be improved with tailored chemical strategies that would serve an individual purpose. Ideally, these chemical manipulations should be efficient, selective, environmentally friendly and economic, in order to truly fulfill their final objective.

    However, despite the ever-expanding rule-book of chemical reactions, target molecules of increasing complexity often face chemists with daunting challenges, whose success rely on multi-step synthetic sequences. There is therefore a permanent need for new, specific methods and strategies that are capable of seamlessly creating C−C bonds, evading the synthesis of difficult or expensive substrates. In this regard, common organometallic reagents display a unique behavior as carbon precursors, in particular as powerful nucleophiles. Reagents based on main-group elements such as lithium or magnesium have therefore played a central role in organic synthesis ever since their discovery. The challenge often lies in controlling their high reactivity, as well as their basic character. Tuning and taming these properties provides chemists with a wide range of unique strategies for the selective synthesis of countless molecular targets.

    In the first part of this thesis, a scalable and stereoselective [3+3] homocoupling of imines in which two C−C bonds are formed in a single step is reported. This reaction relies on an unusual combination of visible-light irradiation and aluminum organometallics. This photochemical process enables the circumvention of the native [3+2] reactivity of these readily available starting materials, thus enabling rapid access to densely functionalized piperazines. Thanks to the congested environment they provide, these heterocyclic scaffolds can be used as ligands to prevent catalyst deactivation through oligomerization.

    The next chapter presents a novel Pummerer-type redox-neutral coupling of sulfoxides and Grignard reagents. This reaction is enabled by a unique turbo-magnesium amide base, and allows the use of a wide range of carbon nucleophiles in intermolecular Pummerer C−C coupling for the streamlined preparation of thioethers. Given the central character of sulfur in organic chemistry, these compounds can then be converted to a variety of unrelated functional groups for the streamlined preparation of diverse building blocks.

    In the final two chapters, the development of a method for the direct conversion of carboxylic acids to ketones with Grignard reagents is described. Using the above-mentioned combination of organometallics, a wide variety of carboxylic acids substrates and Grignard reagents can be coupled in a convenient, scalable and highly selective method that suppresses the need for activation and offers a straightforward approach to ketones from readily available starting materials.

  • Public defence: 2018-11-16 10:00 föreläsningssalen, Institutionen för ekologi, miljö och botanik, Stockholm
    Sörman, Anna
    Stockholm University, Faculty of Humanities, Department of Archaeology and Classical Studies.
    Gjutningens arenor: Metallhantverkets rumsliga, sociala och politiska organisation i södra Skandinavien under bronsåldern2018Doctoral thesis, monograph (Other academic)
    Abstract [en]

    Production and use of metalwork in southern Scandinavia during the Bronze Age (1700-500 BC) has above all been attributed to emerging elites. That bronze was a source and medium for social power is evident from its use in socio-political and ritual spheres, the multiple skills and elaborate aesthetics involved in its crafting, and the arenas for influence and control offered by the acquisition of metals through long-distance exchange. Bronze crafting is often assumed to have been organized at two levels: elite-controlled prestige goods production at centralised workshop sites, set against widespread (controlled or independent) production of utility objects in common households. However, this model is inferred from a functionalist view of finished goods (utility versus prestige) and inspired by anthropological theories, rather than from the material remains of production itself. With evidence of metalworking practices now rapidly increasing due to large-scale contract archaeology, it has become evident that these concepts and interpretations need to be reassessed.

    The aim of this thesis is to develop our understanding of craft organisation through investigation of physical casting sites. Mould and crucible fragments, and their spatial relation to contemporary buildings and other activities, form the main focus of the analysis. I argue that most ceramic casting debris indicates casting loci, and was deposited as secondary waste, or accumulated immediately at the production site. Special, ritual treatment of casting debris is absent, with the exception of complete moulds occasionally found as house offerings in Late Bronze Age longhouses. The Mälar Valley area of eastern Sweden, which has seen particularly intensive archaeological excavation in recent decades, is selected for an in-depth case study, followed by comparisons with other regions of southern Scandinavia. These data demonstrate that bronzes were cast at most, if not all, settlements during the mid-late Bronze Age. Metalworking also occurred at small single farms; a production argued to be dependent on visiting specialists.

    The results reveal complex, user-oriented and multi-tiered craft organisation from Period III onwards. A distinction between prestigious versus utility objects did not structure production. Instead, the organisation and staging of bronze working was shaped by various social roles of the items produced. Rather than special workshop areas, castings were spatially oriented towards future owners. Prestige objects were manufactured in both longhouses and cult-houses within larger settlement complexes, in settings related to the status and gender of their intended users. Further, metalworking often appeared in central and highly visible settings, suggesting it had the character of a performance. I therefore propose that casting –the most dramatic event in the bronze-crafting sequence – was exploited in public or semi-public rituals. Taking into account the social projects and motifs behind new objects, castings were probably linked to transformations such as initiations, inaugurations or establishment of new households. Thus, metalworking played an active and conspicuous role in social reproduction at various levels and in several arenas in the decentralised, heterarchical societies of Bronze Age southern Scandinavia.

  • Public defence: 2018-11-16 13:00 William-Olssonsalen, Geovetenskapens hus, Stockholm
    Rosenqvist, Erik
    Stockholm University, Faculty of Social Sciences, Department of Sociology.
    Social Influence and Educational Decisions: Studies on Peer Influence in Secondary Education2018Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis examines the role of peers when students’ educational decisions are formed. The thesis uses rich administrative data from Sweden, which provides opportunities to follow students over different transitions in their educational career and assess the role of peers in different educational situations. The thesis consists of one introductory chapter and four empirical studies. Study I examines how peers influence each other’s applications to upper secondary education through two different influence functions, where students both conform to their peers’ ambitious decisions and simultaneously can be discouraged from ambitious decisions by high-achieving peers. Study II builds on the findings from Study I and examines if students who conform to their peers’ educational ambitions and enroll in ambitious and demanding educations are more prone to leave such educations since their applications potentially were too myopic when influenced by their peers. Study III examines how students’ decisions to apply to gender typical and gender atypical upper secondary educations were affected by their peers. The study additionally examines if students enrolled in atypical educations are more likely to leave the education and if such decisions are mediated by the peer composition in their upper secondary education. Study IV examines how an admission reform to upper secondary education, which increased the sorting of students on achievements, affected application behavior to different tertiary education.

  • Public defence: 2018-11-16 13:00 hörsal 11, hus F, Stockholm
    Lindgren, Christofer
    Stockholm University, Faculty of Social Sciences, Department of Political Science.
    De små medlens betydelse: Om meningsskapande, mångtydighet och styrning i offentlig förvaltning2018Doctoral thesis, monograph (Other academic)
    Abstract [en]

    Some policy work within public administrations these days seems to rely heavily on individual officials’ efforts to make sense of new policy proposals and practices to other groups in their organizations. This is the case especially with local work on cross-cutting issues such as gender and equal treatment policies, children’s rights issues, sustainability and climate policies etc. Typically, work on these matters are meant to be carried out in all parts of the public sector. However, operations in many parts of this sector are guided by managerial models giving little weight to what is usually perceived as “side issues”. Also, new policy proposals in these areas tend to be formed in complex boundary-spanning practices, involving partnerships and collaborative work, not easily compatible with administrative ideals of clear divisions of tasks and mandates. As a result, the officials responsible for work with these issues often seem to have to invest time in explaining both why certain steps ought to be implemented, and by what legitimate processes they have come about. 

    In this study, such micro-level attempts to gain support for new policy proposals or practices in the administration through efforts to influence the meanings ascribed to them, is seen as a form of steering. The aim of the thesis is to investigate them as such, with the help of governance theory and Karl Weick’s sensemaking perspective. Thereby, the study seeks to provide insights into questions of how this micro-level steering may be analyzed, as well as issues of what they may mean for public administrations’ capacity to make sense of conflicting demands. 

    Theoretically, the study arrives at an analytical model based on two arguments. The first is that attempts to mobilize other members of an administration in complex practices via means of influencing their understanding of these practices, could be seen a project with two thresholds. One concerns the need of explaining what type of situation or practice members are faced with, and how it fits into the order of the administration. The other concerns the need to visualize its aims in such a way that it appears desirable to groups targeted for mobilization. The second argument is that micro-level attempts to influence meaning-making processes in public administrations could be undertaken in both direct and indirect ways. They may come in the form of words and “talk” directly intended to enact certain images in the organization, but also in the form of efforts to stabilize or reinforce the social dynamics holding such images in place. The study discusses several ways in which attempts to manage this dynamic may be carried out.

    Empirically, the analytical model is applied to two case studies focusing on officials working in Swedish municipalities. The task set out for the cases is to investigate the officials’ attempts to gain support for an EU-funded partnership, with the objective of changing recruitment routines in their administrations. The results show that the officials indeed used both direct and indirect means to influence other members understanding of this practice. But also that there appeared to exist a certain dynamic between these means, underlining the need to apply a broad analytical framework when studying this steering, and on a more general note that such steering should be thought of as a product of both communicative and organizing skills.      

  • Public defence: 2018-11-22 10:00 Vivi Täckholmsalen (Q-salen), NPQ-huset, Stockholm
    Drury O'Neill, Elizabeth
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Catching values of small-scale fisheries: A look at markets, trade relations and fisher behaviour2018Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis explores small-scale fisheries trade, markets and the accompanying relationships. It does so to understand how they contribute to human wellbeing and ecosystem health through fisher's behaviour in the marine environment. The capacity of small-scale fisheries to provide for fisherfolk and wider society is currently challenged by human induced ecological threats such as overexploitation and climate change. Small-scale fisheries are increasingly incorporated into the global trading system, which in part drive these ecological changes. At the same time these fisheries are important providers of food and livelihood security for millions of people worldwide. How to realise better fishery governance approaches and enactment is therefore paramount. This thesis attempts to address knowledge gaps in governance and research that centre around the market and actors within it- an area little included in governing fisheries. I draw on the value chain concept and use a mixed methods approach to address three gaps. First, the structure and functioning of small-scale fishery markets and relations. Second, how benefits are distributed in the market and affected by trade relations. Third, I examine how relations and benefit distributions influence fishing behaviour. Case studies are used throughout this thesis drawing on empirical work done in Zanzibar, Tanzania and Iloilo, Philippines. The role of global seafood markets is additionally recognised as a driver of change in all four papers of the thesis. Paper I shows that extending the value chain to combine economic and informal exchanges identifies a wider range of fishery-related sources for human wellbeing within seafood trade. It also highlights more marginal players. Paper II demonstrates how actor's abilities to access economic benefits are impacted by local gender roles and social relations. But these intersect with their value chain position and end-markets. In Paper III local norms appear to play a role in fishing behaviour, more so than market incentives. These dynamics are explored through behavioural economic experiments. Finally Paper IV examines how patronage can have contradictory influences for fisherfolk vulnerability and adaptability. It can also create tensions for overall system resilience when considered at different scales. Overall the thesis contributes to a better understanding of the local to global drivers and interactions in small-scale fisheries trade. The thesis also provides insights into some of the factors influencing the distribution of fishery-related benefits. These aspects have all been cited as vital for designing strategies for improving the wellbeing of people reliant on fisheries.

  • Public defence: 2018-11-23 10:00 De Geersalen, Geovetenskapens hus, Stockholm
    Fernlund, Anders
    Stockholm University, Faculty of Law.
    Franchising: Friktion mellan transnationella affärsmodeller och nationell särreglering2018Doctoral thesis, monograph (Other academic)
    Abstract [en]

    Business models are created by business people in order to achieve a purpose. If a business model is successful, it will be widely used and might become transnational, i.e., not limited by national borders. However, most legislation is limited by national borders. This dissertation analyzes and describes how national legislation affects transnational business models. For purposes of clarity, the transnational business model of franchising has been used as a continuous, concrete example and object for examination.

    This dissertation describes, analyzes, compares and systematizes the business model franchising and its role in the legal system. The study describes the evolution of the business model from the 1850s to the present date. An important question is whether the phenomenon is the same all over the world, i.e., whether it is defined in the same way and bound by the same rules and norms. To find out, a full-range study was conducted of the national legislation directly aimed at franchising in the 36 countries that have introduced such legislation. To widen the focus, definitions and norms from different organizations and projects involved in franchising were also included in the analysis. Through use of a reduction model, a standard definition, like a lowest common denominator, was extracted.

    As only 18 percent of the world’s countries have introduced special legislation on franchising, a sub-study was conducted to analyze if franchise law should be considered a legal field unto its own and hence if it would be viable to legislate specifically about franchising. The study showed that franchising affects and is affected by so many fields of law that it would not be correct to speak about franchise law. Another study covered the 36 countries with specific franchise laws, to analyze the extent of equivalency between these laws, only to show a great variation in the rules. All rules that deviated from the standard definition of franchising were seen as friction rules. The frictions resulting from such rules were described and analyzed. An alternative to specific legislation could be global harmonization through international conventions, model laws or self-regulation. Various actions already taken in these directions were described, compared and analyzed. Another alternative would be not to legislate and instead rely on general legal principles. This was described and analyzed in the dissertation in the light of legislative studies, with both Grant Thornton’s “five stages of drafting” and Lon Fuller’s “desiderata” used to test this option.

  • Public defence: 2018-11-23 13:00 Vivi Täckholmsalen (Q-salen), NPQ-huset, Stockholm
    Pansell, Anna
    Stockholm University, Faculty of Science, Department of Mathematics and Science Education.
    The Ecology of Mary’s Mathematics Teaching: Tracing Co-determination within School Mathematics Practices2018Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Teachers’ mathematics teaching has been studied in many different ways. Such studies not often include more contexts than the teacher’s teaching practice. An assumption in this thesis is that in order to create a deeper understanding of mathematics teachers’ teaching we also need to study the contexts around mathematics teachers, and in relation to each other. Together such contexts create an environment for teachers’ teaching. The determination of how mathematics is taught is not decided in any of the contexts alone. Rather, all contexts participate in the determination of how mathematics is taught and teachers need to negotiate how different contexts privilege both mathematics and mathematics education. In this study, I have studied one teacher’s, Mary’s, teaching practice as well as three contexts from her close environment, the teacher group she participated in, the textbooks she used, and the national curriculum she was bound to follow. To study how mathematics and mathematics teaching was privileged in the four studied contexts became a way to trace how the contexts participate in the determination, in short, their co-determination of how mathematics is taught.

    With an aim to deepen the understanding of how the environment of a teacher’s teaching enables and constrains mathematics teaching, the four contexts were studied in relation to each other in different ways, in four studies. First, the context of Mary’s mathematics teaching was studied in relation to the teacher group in how the justifications of Mary’s mathematics teaching was constituted in relation to a teacher group discussion. Second, Mary’s teaching of problem-solving was studied in relation to how problem-solving was privileged in both mathematics textbook and national curriculum. Third, praxeology was explored as an analytical tool to understand how mathematics was privileged in teaching practice in relation to the privileging of mathematics in textbooks. Fourth, all four contexts were studied to trace arguments and principles for teaching rational numbers and how these enable and constrain the teaching of rational numbers.

    To address these different contexts, ATD as described by Chevallard was adopted. In ATD, the environment of contexts with influence of teachers’ practices, is described as an ecology with levels that co-determine each other. The studied contexts represented some of these levels of co-determination. The privileging of mathematics and mathematics teaching was studied from a varied data material. Data from Mary’s teaching practice was transcripts of classroom observations and interviews. Data from the teacher group was transcripts of teacher meetings. Data from the textbook context was the textbooks and teacher guides Mary used. Data from the context of the national curriculum was the mathematics syllabus accompanied with clarifying and explanatory comments.

    The analyses revealed a strong resemblance of the mathematical communication between the different contexts. They all emphasised similar approaches to problem-solving, aspects of rational numbers, mathematical values, or explanations of angles. Mary, however, anchored her arguments for mathematics teaching in partially different theoretical principles than those privileged in the ecology. Theoretical principles were not explicitly communicated in any context. They were inferred from the communication. An implication generated by these findings is the importance for teachers to engage in the principles behind the privileging expressed in contexts they need to negotiate. These principles need to be discussed and challenged. Another implication is the relevance of allowing for teachers to engage in research literature, and to have influences from other sources than their immediate contexts. The thesis also point to the need to study textbooks and national curriculum, not in terms of how they are enacted by teachers, but what they privilege. By doing so teachers practices may be understood in the sense of what teachers have to negotiate, where the consequence is a deeper understanding of constraints and affordances for teachers’ teaching practices.

  • Public defence: 2018-11-23 13:00 Högbomsalen, Geovetenskapens hus, Stockholm
    Hirst, Catherine
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Iron in the Lena River basin, NE Russia: Insights from microscopy, spectroscopy and isotope analysis2018Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Iron is an important mediator of biotic and abiotic processes on the Earth’s surface, being an electron acceptor in organic matter degradation, a surface for organic matter and trace element adsorption, and a required element for enzymatic processes during primary production. Yet, the role of iron as a mediator of carbon and trace element cycling in high latitude, permafrost-dominated regions remains poorly investigated. The aim of this study was to characterise the chemical reactivity (by size separation, microscopy and spectroscopy) and sources (by isotope composition) of Fe in the Lena River and major tributaries, spanning a wide range in lithology, topography and climate. The Fe transported in the Lena River and major tributaries carries an integrated signal of Fe weathering processes across the permafrost-dominated terrain.

    A spatial sample set was collected during the post-spring flood period (July 2012, June 2013), from the main channel and tributaries draining contrasting topography and permafrost extent. Across the basin, Fe is mainly transported as chemically reactive ferrihydrite that spans the particulate (> 0.22 µm) and colloidal (0.22 µm – 1 kDa) fractions. The remaining Fe transported as poorly reactive detrital Fe in clays and crystalline oxides. Fe is transported in larger size fractions than the dissolved OM showing that Fe is not a major carrier of DOM. Nano-sized ferrihydrite was attached to OM in the particulate fraction, evidence of a Fe – OM particle association in the Lena River basin.

    Ferrihydrite shows distinct isotope values in particulate and colloidal fractions, showing that there is a difference in isotopic composition between different size fractions of the same mineral. A conceptual model was developed to understand ferrihydrite formation in the riparian zone of the Lena River and tributaries.  Particulate ferrihydrite has isotope values lower than crustal values resulting from redox and organic-ligand promoted mineral dissolution and precipitation of Fe(II)aq to form coatings of ferrihydrite on particles in the riparian zone.  Ferrihydrite colloids span a wider range of isotope values, higher than Fe particles, resulting from variations in the size and isotope composition of the Fe(II)aq pool transported in soil groundwaters, and the isotope fractionation factor for Fe oxidation and organic complexation.

    A temporal sample set was collected in the main channel between September 2012 – March 2013 and every three days during May 2015. The colloidal Fe shows distinct seasonal Fe isotope signatures and Fe fluxes, with isotope values lower than crustal during winter baseflow, overlying crustal values during spring flood and higher than crustal values during summer, attributed to changing sources and thus conditions for isotope fractionation. The combined understanding of Fe reactivity and isotope composition allows us to isolate the dominant sources of Fe entering the Lena River.

  • Public defence: 2018-11-23 13:00 Gröjersalenhus 3, Stockholm
    Klemcke, Liesel
    Stockholm University, Faculty of Social Sciences, Stockholm Business School.
    The Quirky Character Camouflaged in the Conceptual Framework: A study of the financial statement user2018Doctoral thesis, monograph (Other academic)
    Abstract [en]

    Much of accounting research implies that someone uses financial statements in making investment decisions, and assumes that the ones using the statements are financial analysts, investment bankers, fund managers, or the rational economic decision maker. However, these assumptions do not consider all potential investors, particularly those who have traditionally lacked access to information and technical savvy. However, there is a financial statement user lacking information access, who makes a brief, nearly camouflaged appearance in the financial reporting conceptual framework.

    This dissertation explores the possibility of this other financial statement user, who is different from the usual taken for granted analyst or a rational economic decision maker. Conducting an historical study into the origins of regulated financial reporting in tandem with the development of the accounting profession, this dissertation locates the sites where financial reporting transforms and allows for different conceptualizations of the user.  This study of the financial statement user is a genealogy that utilizes a coproductionist approach, which considers the influence of the decision useful objective of financial reporting in tandem with the role of the accounting profession in the development of both regulated financial statements and the financial statement user. 

    In the process of investigating this other financial statement user, this dissertation reveals how important the user is to accounting. Thus, this dissertation contributes not only to studies concerning the user and user primacy, but also to studies concerning the accounting profession, the financial reporting conceptual framework, and accounting principles. This other user, or the quirky character camouflaged in the conceptual framework, has greatly impacted the accounting profession, accounting concepts, the capital market, and a controversial accounting principle still in use today.

  • Public defence: 2018-11-29 09:30 Vivi Täckholmsalen (Q-salen), NPQ-huset, Stockholm
    Sellberg, My M.
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Advancing Resilience Practice: Bridging social-ecological resilience theory and sustainable development practice2018Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis investigates the application of resilience thinking in different real-world settings and research-practice interfaces, for example in the context of natural resource management, local government planning and food systems. The number of cases of resilience practice are growing, including resilience assessments, planning and action, but there are still few scientific studies and even less synthesis across cases. This thesis describes existing cases of resilience practice, in natural resource management in Australia (Paper I) and across different international cases (Paper II), and experiments with new methods and approaches for improving resilience practice, based on pilot projects of co-production in Sweden (Paper III and Paper IV). The results confirm that resilience practice can contribute to the understanding and adaptive governance of complex social-ecological systems, but is weak in addressing the need for transformations, particularly for the sake of the resilience of Earth systems and global sustainability. The results also highlight practical strategies for engaging with complexity and novel approaches to enhance the potential of local-regional resilience practice to align with global sustainability concerns. The thesis as a whole sheds light on the field of resilience practice, by outlining different approaches, contexts and purposes and contributes to building transdisciplinary networks and relationships in multiple arenas.

  • Public defence: 2018-11-29 13:00 Gröjersalen, hus 3, Kräftriket, Stockholm
    Chowdhury, Abu
    Stockholm University, Faculty of Social Sciences, Stockholm Business School.
    Essays on Insider Trading and Initial Public Offerings2018Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

       This thesis consists of four self-standing articles on insider trading, initial public offerings and delisting of corporate firms.

       The first paper in this thesis investigates whether insiders, in an asymmetric information environment, manipulate the earnings of a firm to influence investors’ perceptions of firm value in order to benefit from their trades. The main finding of this paper is a positive association between accrual-based earnings management and sell-dominated insider trading given the existence of asymmetric information. We find a leading role for information asymmetry and its interaction effect on the relationship between insider trading and discretionary accrual proxies.

       The second paper examines the opportunistic trading behavior of core insiders compared with non-core ones. We document that although both core and non-core insiders are equally motivated by contrarian beliefs, their motivational difference in opportunistic trading is primarily connected to preferential and favored access to superior private information.

       The third paper investigates the role underwriters play in initial public offerings on Mondays. Our evidence suggests that underwriters are reluctant to take firms public on Mondays, as they face uncertainty about pricing the IPOs due to the lack of information and a greater risk of not being able to sell stocks at the offer price, thus losing money. However, they bring IPOs on Mondays, as they are sufficiently underpriced to minimize their risks.

       The fourth paper investigates the roles of institutional investors and insiders in the delisting of firms – an important corporate event. Our analysis reveals that institutional holdings have a negative effect on a firm’s probability of being delisted within five years after the IPO. We also find that insider purchases have a negative effect and insider sales have a positive effect on the probability of delisting. Our result further shows that the probability of delisting decreases if firms’ insiders increase their holdings.

  • Public defence: 2018-11-30 09:00 Rehabsalen, Stockholm
    Ardenfors, Oscar
    Stockholm University, Faculty of Science, Department of Physics.
    Out-of-field doses from proton therapy and doses from CBCT imaging: Risk of radiation-induced second cancer from modern radiotherapy2018Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The use of ionizing radiation for treatment of cancer diseases is continuously increasing as patient survival is improving and new treatment techniques are emerging. While this development is beneficial for curing primary tumors, concerns have been raised regarding the unwanted dose contribution to healthy tissues of patients and the associated risk of radiation-induced second cancer (RISC). This is especially important for younger patients receiving radiotherapy more often than before and for whom the risk of developing RISC is elevated in comparison to the typical adult radiotherapy patient. In order to estimate the risk of RISC associated with modern radiotherapy and imaging, the associated radiation doses must be determined.

    Patients undergoing radiotherapy receive in-field doses from the primary beam but also out-of-field doses originating from secondary radiation produced in the beamline and within the patient. Over the last years, the use of proton pencil beam scanning (PBS) therapy has rapidly increased due to its potential to reduce the in-field doses to healthy tissues in comparison to photon therapy. One of the drawbacks with proton therapy is the production of neutrons capable of travelling large distances and depositing out-of-field doses to organs located far from the primary treatment field. The dose reduction associated with proton PBS therapy could consequently be affected by the out-of-field doses originating from secondary radiation.

    The sharp dose gradients associated with modern treatment techniques, such as photon intensity-modulated radiotherapy (IMRT) and proton PBS therapy require more frequent and accurate patient imaging in comparison to conventional treatment techniques such as three-dimensional conformal radiotherapy (CRT). Setup verification images could be acquired with cone-beam computed tomography (CBCT) producing three-dimensional patient images at the cost of an increased patient dose in comparison to planar x-ray imaging. Concerns have been raised regarding the cumulative patient doses from repeated CBCT imaging versus the dose-saving benefits associated with modern radiotherapy techniques like IMRT and proton PBS.

    In this thesis, a study on the in-field and out-of-field doses to healthy tissues from photon IMRT and CRT treatments of head and neck tumors showed that the risk of RISC was unaffected by the employed treatment technique and indicated that the lifetime risk of cancer induction was of the order of 1-2%.

    Results from measurements and Monte Carlo simulations showed that the out-of-field absorbed doses and equivalent doses associated with proton PBS treatments of brain tumors were up to 60 µGy/Gy and 150 µSv/Gy, respectively. The risk of RISC associated with these out-of-field doses was in the range of approximately one induced cancer in ten thousand treated patients. A simulation study on the doses from a proton gantry-mounted CBCT system showed that repeated CBCT imaging could result in cumulative organ doses of almost 2 Gy. The conclusion from these studies is that the dose-sparing effects of proton PBS therapy are not overshadowed by the out-of-field doses originating from secondary radiation for brain tumor treatments, but that the cumulative doses from repeated CBCT imaging could have a relevant impact on the overall dose reduction.

  • Public defence: 2018-11-30 09:00 William-Olssonsalen, Stockholm
    Jansson, Joakim
    Stockholm University, Faculty of Social Sciences, Department of Economics.
    We are (not) anonymous: Essays on anonymity, discrimination and online hate2018Doctoral thesis, monograph (Other academic)
    Abstract [en]

    Haters gonna hate? - Anonymity, misogyny and hate against foreigners in online discussions on political topics. A crucial aspect of freedom of expression is anonymity, but anonymity is a contentious matter. It enables individuals to discuss without fear of repercussions, but anonymity can also lead to hateful writings threatening other's freedom. In this paper, we predict hateful content as well as estimate the causal link between anonymity and hateful content in civic discussions online. First, we make use of a supervised machine-learning model to predict hate in general, hate against foreigners and hate against females and feminists on a dominating Swedish Internet discussion forum. Second, using a difference-in-difference model we show that an exogenous decrease in anonymity leads to less hateful content in general hate and hate against foreigners, but an increase in hate against females and feminists. The mechanisms behind the changes is a combination of a decrease in writing hateful, as well as a decrease in writing in general and a substitution of hate against one group to another.

    Gender grading bias at Stockholm University: quasi-experimental evidence from an anonymous grading reform. In this paper, we first present novel evidence of grading bias against women at the university level. This is in contrast to previous results at the secondary education level. Contrary to the gender composition at lower levels of education in Sweden, the teachers and graders at the university level are predominantly male. Thus, an in-group bias mechanism could consistently explain the evidence from both the university and secondary education level. However, we find that in-group bias can only explain approximately 20 percent of the total grading bias effect at the university level.

    Anticipation Effects of a Board Room Gender Quota Law: Evidence from a Credible Threat in Sweden. Board room quota laws have recently received an increasing amount of attention. However, laws are typically anticipated and firms can react before the effective date. This paper provides new results on female board participation and firm performance in Sweden due to a credible threat of a quota law enacted by the Swedish deputy prime minister. The threat caused a substantial and rapid increase in the share of female board members in firms listed on the Stockholm stock exchange. This increase was accompanied by an increase in different measures of firm performance in the same years, which were related to higher sales and lower labor costs. The results highlight that anticipatory effects of a law could be detrimental to the analysis.

    Differences in prison sentencing between the genders and immigration background in Sweden: discrepancies and possible explanations. I use data on punished drunk drivers to document differences in sentencing for the same crime between immigrants and native born and males and females respectively. Differences in past criminal activity or other individual observables can not explain the difference in sentencing. Instead, the difference between immigrants and native born seem to be due to statistical discrimination, while differences in recidivism rates might explain the gender difference. However, the higher incarceration rate for immigrants does not reduce their future number of crimes.

  • Public defence: 2018-11-30 10:00 Vivi Täckholmsalen (Q-salen), NPQ-huset, Stockholm
    Rasmussen, Pil Uthaug
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Plant-associated soil communities: Patterns, drivers and aboveground consequences2018Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Soil contains a wealth of diversity – bacteria, fungi, nematodes, arthropods and earthworms are just some of the many organisms found belowground. These organisms play an important role in shaping the soil environment and they strongly influence plant fitness, diversity and community composition. Their impact even cascades up to affect aboveground species interactions. Ultimately, belowground organisms are a vital part of ecosystem functioning. Nevertheless, most of the diversity and ecology of belowground organisms are to this day unknown, and increasing our insights into the role and ecology of soil organisms is of importance for natural and agricultural systems.

    The main goal of this thesis was to investigate spatial patterns of plant-associated soil communities (I, II), to identify the drivers of such spatial patterns (I, II, III), and to study some of the consequences of belowground spatial patterns for aboveground species interactions (IV). To answer these questions, I used both observational studies and multifactorial experiments in combination with microscopy and metabarcoding. I focused on the plant Plantago lanceolata (ribwort plantain) and its root-associated soil microbes, with a strong emphasis on arbuscular mycorrhizal fungi, an important group of root symbionts.

    I found that in natural environments arbuscular mycorrhizal fungal communities frequently show high small-scale variation (I). In the following work I showed that the pattern of high small-scale heterogeneity may be due to dispersal limitation (II), abiotic conditions such as pH, soil nutrients and climate (I, III), and biotic conditions, such as interspecific community composition and genetic variation (I, II). The high variation at small spatial scales (I) in combination with genetic variation of plants and insects (IV) may help maintain high local heterogeneity in aboveground plant-associated communities, thereby influencing aboveground diversity and dynamics.

    The insight gained here has increased our general knowledge on the distribution of soil microbes and the interactions taking place above and belowground. It has furthermore laid a foundation for future work on the world of soil microbes and their implications aboveground.

  • Public defence: 2018-11-30 13:00 Auditorium 215, Humanistvillan, Stockholm
    Solheim, Randi C.
    Stockholm University, Faculty of Humanities, Department of Culture and Aesthetics.
    Kunst og nasjon: Brytninger i kunstsynet i Norge 1750–19052018Doctoral thesis, monograph (Other academic)
    Abstract [en]

    The thesis examines the art theoretical discourse, in Norway, from the mid eighteenth century up to 1905. The objective of the study has been to identify and analyse the most important art theoretical positions in treatises and other programmatic texts and works of art. The source material has been analysed through close reading of the texts, and through detailed examination of the chosen artworks. The focus is on discourse that is understood, in the traditional sense, as an exchange of ideas or communication between individuals where there exists a difference of opinion. This model is inspired by Jürgen Habermas’ theory of communicative action and represents a kind of analytical pluralism that differs from the discourse model associated with Michel Foucault.

    The period examined has been chosen both from a political and from a discursive point of view. Norway in the examined period transformed from a pre-modern society into a modern nation state. It was also in this period art became a national concern. Prior to 1814, Norway was part of a larger Danish-Norwegian conglomerate state with the capital Copenhagen. From 1814 up to 1905 Norway had a semi-autonomous status with its own capital, Christiania, within a personal union under a common monarch with Sweden.

    The hypothesis of the thesis is that the art theoretical conflicts are expressions of hegemonic rivalries between elites with differing national strategies. This perspective, which implies a struggle over ideas and positions, transgresses Habermas’ consensus model. The power perspective takes into consideration that some positions might be marginalised or supressed in art historical writing. By acknowledging these positions, the thesis also has a critical art historiographic ambition.

    The analysis is organised in four chapters that correspond to distinct socio-cultural periods. The first chapter, Kierlighed til Fædrenelandet, deals with the period from the mid-eighteenth century up to 1814. The focal point of this period is on the art theoretical discourse connected to the development of the Royal Academy of Art in Copenhagen. In the second chapter, Patriotismens borgerkrig, the prime focus is on the effort of building art institutions in the new Norwegian capital Christiania, and the controversies regarding the nation’ s artistic culture. The third chapter, Den store harmonien, highlights the identity politics after 1850 and the resulting disputes over the national art. The fourth chapter, Harmoni gjennom differensiering, targets the diversity of art theoretical standpoints competing for hegemony from the mid-1870s to 1905.  

    The results of the study show that the dividing line in the art theoretical conflicts in Norway, during the period of examination, primarily goes between a humanistic orientated secular elite and an ecclesiastically trained elite. The issues of dispute can be grouped around two different themes. These themes often appear as dichotomies, where two fundamental differences of opinion emerge. The first is the conflict between a utilitarian view on art versus the view of art as luxury. The second dichotomy can be traced to the discord between an individualising and an archaic stylistic idiom. These divides are in turn indicative of the conflict between two divergent educational ideals. One reflecting humanist scientific ideals, the other based on scholastic theological values.

  • Public defence: 2018-11-30 13:00 Gröjersalen, hus 3, Kräftriket, Stockholm
    Magalhães Lopes, Maíra
    Stockholm University, Faculty of Social Sciences, Stockholm Business School.
    The Making of Us: How affects shape collective bodies resisting gentrification2018Doctoral thesis, monograph (Other academic)
    Abstract [en]

    This thesis explores how we can think of collective bodies as amalgamations of interplaying affects (i.e., multiplicities), rather than compositions of individuals. Using ethnography as my main method, I study urban activism collectives resisting gentrification in the city center of São Paulo, Brazil. Following affect-based theorizing, I focus on the collective body as a composition of affective intensities. I explore disgust, fear, (dis)comfort, and hope as affective intensities that travel with different orientations, directions, and potencies. I take the position that, through such travelings, bodily surfaces become felt and unfelt. That is, I explore the surfacing of the collective body as a continuous process through the circulation and accumulation of such affects. I also explore how collective bodies become organized as packs and crowds, whilst disputing spaces for consumption within a gentrification process. Whereas packs are seen as a condensed form of multiplicities, crowds are expanded forms of multiplicities. The findings of this thesis then contribute to the marketplace culture literature by exploring how the formation of the collective body is a continuous affective process that unfolds into different forms of multiplicities (i.e., packs and crowds). This study proposes viewing the collective body as a continuous process of affective amalgamation. This study also contributes to extant CCT studies regarding affect and emotions. The findings of this study interlink felt experiences with surfacing effects. That is, I focus the analysis on how affects work in delineating the relation between and of bodies and, thereby, marking what we understand as I, you, us, and them. Thirdly, this study also contributes to discussions regarding space and place in marketing. This study extends the discussion regarding spatial injustices and neoliberal cities, which are driven by wider consumption ideology.

  • Public defence: 2018-11-30 14:00 De Geersalen, Geovetenskapens hus, Stockholm
    Pauthenet, Etienne
    Stockholm University, Faculty of Science, Department of Meteorology .
    Unraveling the thermohaline structure of the Southern Ocean using functional data analysis2018Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The Southern Ocean connects the Indian, Pacific and Atlantic Oceans and provides a direct pathway to exchange mass, heat and salt across the Global Ocean, therefore playing an important role in the global climate system. Due to the complexity of its structure and the general inadequacy of its sampling, both in time and space, it remains a challenge to describe and visualize the three dimensional pattern of its circulation and the associated tracer distribution (temperature, salinity, oxygen or nutrients). This thesis contributes to the understanding of the thermohaline structure of the ocean and especially of the remote Southern Ocean by introducing a novel decomposition method, the Functional Principal Component Analysis applied on vertical profiles of temperature and salinity. To this end, we first normalize hydrographic profiles by using a functional spline representation. Then the statistical method of dimension reduction and feature extraction reveals the main spatial patterns of the temperature and salinity variations. The first two vertical modes contribute to 90% of the combined variance and are related to very robust structures of the Global Ocean. The first mode is mainly controlled by temperature and the second by salinity. In the Southern Ocean, the vertical modes present circumpolar patterns that can be closely related to the stratification regimes that define the circumpolar fronts. Notably the Polar Front is located at the natural boundary between the region controlled by the first (thermal) mode to the north and the second (haline) mode to the south. A mapping of the fundamental zonation is provided with an estimate of the width of the water mass boundaries. As a validation of this method, the Antarctic Polar Front is investigated further in the Indian sector using the same statistical framework. We show that the Polar Front latitudinal position varies seasonally upstream of the Kerguelen Plateau. This meandering is confirmed by hydrographic data gathered by elephant seals equipped with miniaturized sensors. The proposed statistical method provides an objective way to define water mass boundaries and their spatial variability. It offers a useful framework for representing the density structure of the ocean in a reduced-dimension space while maximizing the variance explained. The functional approach also provides a robust way to validate model outputs against observations from any platforms.

  • Public defence: 2018-12-05 10:00 Magnélisalen, Kemiska övningslaboratoriet, Stockholm
    Shatskiy, Andrey
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Ru-Based Water Oxidation Catalysts: Development and Mechanistic Studies2018Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Oxidation of water constitutes one of the most challenging processes in artificial photosynthesis, which aims at storing solar energy in the form of chemical bonds of high-energy fuels. To facilitate this process, efficient and durable water oxidation catalysts have to be developed and integrated into the complete photosynthetic cells. Importantly, the intricate complexity of such devices requires the catalyst not only to be highly efficient and robust, but also operate through a well-defined mechanism.

    This thesis describes the development and mechanistic studies of new water oxidation catalysts based on ruthenium. The first part of the thesis describes the synthesis of a dinuclear ruthenium-based catalyst active for both chemical and light-driven water oxidation. This catalyst displayed a pronounced influence of the acetonitrile co-solvent on the redox properties, which was studied in detail by electrochemical methods. In the second part, a new benzimidazole-based mononuclear catalyst was evaluated. The activity of the catalyst was studied for chemical and light-driven water oxidation, and insight into the operating mechanism was provided with the help of density functional theory calculations. In the third part of the thesis, a new mononuclear ruthenium-based catalyst was prepared and evaluated for electrochemically-driven water oxidation. This catalyst displayed activity similar to that of the current state-of-the-art water oxidation catalyst, while eliminating its main drawback, that is incomplete activation. The redox properties of the new catalyst were studied in detail by electrochemical and spectroscopic techniques, providing insight into the origins of its improved performance. Finally, in the fourth part of the thesis, a heterogeneous nanoparticulate catalyst immobilized on a solid support is described. The catalyst displayed high activity and stability during chemical and light-driven water oxidation, which was attributed to the small average particle size and efficient anchoring of the catalyst to the heterogeneous support via an oxidatively-stable linker.

  • Public defence: 2018-12-05 13:00 Nordenskiöldsalen, Geovetenskapens hus, Stockholm
    Zurita, Javier
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Amino acids with relevance to health, climate and the environment: Development of mass spectrometric methods2018Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Amino acids play vital roles in health, either in their native form or chemically modified. Some studies have linked certain non-proteinogenic amino acids to neurodegenerative diseases, such as in the case of β-methylaminoalanine (BMAA). Various environmental pollutants, including carcinogenic polycyclic aromatic compounds, are able to react forming adducts with blood proteins. Amino acids may also be essential in chemical ecology as constituents of flower nectar, potentially used by common feeders as butterflies to synthesize pheromones. Additionally, proteinaceous materials have been detected in aerosols with an apparent potential to influence climate, possibly having a role in cloud formation.

    The determination of amino acids presents many challenges, due to the fact that they are most often constituents of complex sample matrices that contain a high level of chemical interferences. In this respect, mass spectrometry (MS) is a selective and sensitive analytical tool that can be used to measure amino acids in biological samples.

    In this work, several analytical methods based on MS were developed. (i) First, derivatization with a permanently charged N-hydroxysuccinimide ester of N-butylnicotinic acid (C4-NA-NHS) was used to increase the sensitivity and selectivity for amino acids. This strategy was applied to localize BMAA in both visceral and non-visceral parts of blue mussels. (ii) Moreover, a method was developed to separate and determine L- and D- BMAA in cycad seeds by derivatization with a chiral reagent, (+)-1-(9-fluorenyl) ethyl chloroformate (FLEC). Together with L-BMAA, appreciable amounts of D-BMAA (50.13 ± 0.05 and 4.08 ± 0.04 µg BMAA/g Cycas micronesica, wet weight, respectively) were detected for the first time after enzymatic digestion, suggesting D-BMAA may be bound to proteins or may be a conjugate and released only after hydrolysis. (iii) Derivatization with C4-NA-NHS was applied as well for the determination of amino acids in nectar of Bunias orientalis. The presence of tryptophan and phenylalanine, purportedly used to synthesize anti-aphrodisiac pheromones by nectar feeders (adult male butterflies), could then be observed. (iv) Furthermore, the profiling of amino acids in Arctic aerosols was carried out and was used to measure the contribution of free and polyamino acids in aerosol formation. Levels detected were in the range of 0.02-2914 pmol/m3 sampled air. For the first time the measurement of polyamino acids in the Arctic atmosphere was reported. Additionally, possible anthropogenic and marine sources were suggested. The results support the hypothesis that proteinaceous materials act as cloud condensation nuclei over the Arctic. (v) Finally, a method was developed employing selective chromatography/high-resolution MS to identify histidine and lysine adducts in serum albumin of mice exposed to the carcinogen benzo(a)pyrene, as well as in human samples in vivo. Adduct isomers from diol epoxide metabolites could be detected in serum albumin from human samples at attomole/mg levels. This work shows the possibility of future exposure measurements from these compounds in different groups of the population.

    This thesis presents the development of improved analytical methodologies for detecting and identifying trace levels of amino acids, to investigate their relevance in health, climate and the environment.