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  • Public defence: 2018-12-13 10:00 sal 14, hus 5, Kräftriket, Stockholm
    Stocks, Theresa
    Stockholm University, Faculty of Science, Department of Mathematics.
    Stochastic dynamic modelling and statistical analysis of infectious disease spread and cancer treatment2018Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Mathematical models have proven valuable for public health decision makers as they can provide insights into the understanding, control and, ultimately, the prevention of diseases. This thesis contains four manuscripts dealing with stochastic dynamic modelling and statistical analysis of infectious disease spread and optimization of cancer treatment.

    Paper I is concerned with deriving a patient- and organ-specific measure for the estimated negative side effects of radiotherapy using a stochastic logistic birth-death process. Our analysis shows that the region of a maximum tolerable radiation dose can be related to the solution of a logistic differential equation; we illustrate our results for brachytherapy for prostate cancer.

    Paper II and III deal with inference for stochastic epidemic models. Parameter estimation for this model class can be challenging as disease spread is usually only partially observed, e.g. in the form of accumulated reported incidences within specified time periods. To perform inference for these types of models, a useful method for maximum likelihood estimation is iterated filtering which takes advantage of the fact that it is relatively easy to generate samples from the underlying transmission process while the likelihood function for the given data is intractable.

    Paper II is an application-oriented introduction to iterated filtering via the R package pomp (King et al., 2016) which contains a wide collection of simulation-based inference methods for partially observed Markov processes. We review the theoretical background of the method and discuss by two examples its performance and some associated practical difficulties.

    Paper III is concerned with model selection for partially observed epidemic models that differ with respect to the amount of variability they allow for and parameter estimation of those models from routinely collected surveillance data. We illustrate the model selection and inference framework via the R package pomp for rotavirus transmission in Germany, however, the method can be easily adapted to other diseases.

    In Paper IV we develop a transmission model for hepatitis C virus (HCV) infection among people who inject drugs (PWIDs) to enable countries to monitor their progress towards HCV elimination. In the scope of the WHO’s commitment to viral hepatitis elimination, this topic is highly relevant to public health since injection drug use is the main route of transmission in many countries. From the model and using surveillance data, we derive estimates of four key HCV-indicators. Furthermore, the model can be used to investigate the impact of two interventions, direct-acting antiviral drug treatment and needle exchange programs, on the disease dynamics. In order to make the model and its output accessible to relevant users, it is made available through a Shiny app.

  • Public defence: 2018-12-13 10:00 Magnélisalen, Kemiska övningslaboratoriet, Stockholm
    Rydström Lundin, Camilla
    Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics.
    Modulators of Saccharomyces cerevisiae cytochrome c oxidase: Implications for the regulation of mitochondrial respiration2018Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Oxidative phosphorylation in mitochondria is performed by enzyme complexes and electron carriers that reside in the inner membrane. It is now generally accepted that these respiratory enzyme complexes assemble into larger so-called supercomplexes. However, it is presently not known why, under which conditions or how these supercomplexes form.

    A number of factors of particular importance for the formation of supercomplexes have been identified, such as the Respiratory supercomplex factors (Rcf1 and Rcf2) and cardiolipin. The work presented in this thesis is focused on the characterization of cytochrome c oxidase (CytcO) in mitochondria from Saccharomyces cerevisiae strains in which these components have been removed, with a particular focus on Rcf1. First, we concluded that Rcf1 has an impact on the activity and ligand binding kinetics of CytcO, which upon genetic deletion of rcf1 leads to formation of sub-populations of CytcO with different functionality. Second, we noted that the ability of CytcO to oxidize cytochrome c (cyt. c) depends on the presence of Rcf1. Further, we observed that while CytcO in wild-type mitochondria displayed differences in the oxidation kinetics of cyt. c from horse heart or S. cerevisiae, with the Δrcf1 mitochondria these differences were lost. This observation suggested that Rcf1 interacts with cyt. c. Furthermore, the data showed that in CytcO from Δrcf1 mitochondria heme a3 was altered while heme a was intact.

    Using proteo-liposomes of different lipid composition and size we also investigated the influence of lipid head groups on the coupled activity of a quinol oxidase and ATP-synthase. Specifically, we addressed the question if protons are transferred between proton “producers” and “consumers” via lateral proton transfer along the membrane surface or via bulk water. Our data supported the principle of lateral proton transfer.

    Lastly, we characterized the ligand binding of yeast flavohemoglobin and concluded that the flavohemoglobin has a population that resides in the intermembrane space of mitochondria, not only in matrix and cytosol as previously suggested.

  • Public defence: 2018-12-14 09:00 hörsal 12, hus F, Stockholm
    Marklund, Ulrika
    Stockholm University, Faculty of Humanities, Department of Linguistics.
    Turn-taking and early phonology: Contingency in parent-child interaction and assessment of early speech production2018Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis focuses on contingency in parent-child interaction, investigating it in the light of the linguistic capacity of the child and the status of the caregiver. Further, the thesis covers the development of two tools to assess the developmental maturity level of expressive phonology. A functional emergentist perspective on language acquisition is taken, which includes a phonetic perspective on phonological development. Both infant language development and factors that influence parent responsiveness are explored. 

    The thesis contains four studies. In the first study, durations of parents’ utterances and pauses in interaction with their 18-month-old infants were related to the infant’s vocabulary size. Recordings of interactions of fifteen children and their parents were made at home in daily life situations. The children were divided into three groups according to their vocabulary size: large, typical or small. The main finding is that parents in the large vocabulary size group responded faster to their children compared to the parents in the typical size vocabulary group, who in turn responded faster than the parents in the small vocabulary size group. 

    In study two, duration in vocal turn-taking between 6-month old infants and their caregivers was investigated, in terms of the status of the caregiver and the sex of the infant. Caregivers’ pauses were measured in 10-minute caregiver-infant interactions recorded at home. It was found that primary caregivers responded faster to their infants compared to secondary caregivers, and that in turn, infants responded faster to the primary caregiver than to the secondary caregiver. 

    Study three introduces the Word Complexity Measure for Swedish (WCM-SE), a tool for calculating phonological complexity in words or utterances. Calculations are based on ten parameters describing speech structures that are considered phonetically complex to produce. In the development of  the WCM-SE, both language-specific and language-general descriptions of speech development were considered, as well as universal acoustic and aerodynamic principles. 

    Study four documents the selection of Swedish words for the word lists in the test Profiles of Early Expressive Phonological Skills for Swedish (PEEPS-SE). The selection was based on criteria of age of acquisition and word complexity, as measured by the WCM-SE. 

    The findings presented in this thesis contribute to our knowledge of early interaction and parents’ potential impact on the child’s early language and communication development. Further, the tools developed for the assessment of Swedish are valuable contributions both to the research field of early phonology and to clinical work in Sweden. 

  • Public defence: 2018-12-14 13:00 William-Olssonsalen, Geovetenskapens hus, Stockholm
    Koliev, Faradj
    Stockholm University, Faculty of Social Sciences, Department of Political Science.
    Naming and Shaming: The politics and effectiveness of social pressure in the ILO2018Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    In the current international system, the use of centralized, hard enforcement mechanisms is often deemed either politically impossible or too costly. As a consequence, many international organizations (IOs) rely on so-called naming and shaming strategies as tools of political influence. Naming and shaming is the public exposure and condemnation of states that violate international rules and norms. It is not designed to simply renegade violators, but to produce compliance through reputational and status concerns. But how does naming and shaming work and what impact does it have on state behavior? In this dissertation, I adopt a comprehensive approach to the study of naming and shaming by examining its underlying politics and determinants as well as its impact on state behavior. In search for answers, I focus on the naming and shaming strategies employed in the International Labour Organization (ILO) during the period 1989-2011. Drawing on the theories of international politics, I develop a set of hypotheses that are tested by means of statistical as well as process tracing techniques. The overall conclusions of the dissertation are fourfold. First, the results indicate that ILO naming and shaming is used to punish violators of international labor standards. This implies that IOs, under the right conditions, can thwart the politicization of naming and shaming that has been observed in other IOs. Second, I find support for my argument that the decision to engage in naming and shaming primarily is determined by the democratic character of states. This enhances our understanding of when states participate in pressuring targets and the patterns of inter-state shaming. Third, the dissertation finds that ILO naming and shaming can improve international labor standards. The impact of ILO naming and shaming is stronger when target states are democratic and resourceful. This implies that IOs can overcome international collective problems without hard enforcement mechanisms and that IO naming and shaming, under certain propitious conditions, can produce compliance. Fourth, while democracies are more likely to respond to international criticism, not all democracies do. This dissertation demonstrates that ILO naming and shaming is a powerful tool among democracies that have strong and united labor unions. This implies that IO naming and shaming of democratic states is likely to work through domestic pressure mechanisms.

  • Public defence: 2018-12-14 13:00 De Geersalen, Geovetenskapens hus, Stockholm
    Lorentzon, Ylva
    Stockholm University, Faculty of Social Sciences, Department of Child and Youth Studies.
    Öppna världar, slutna rum: Om status och barnkulturpolitik i scenkonstens vardagspraktik2018Doctoral thesis, monograph (Other academic)
    Abstract [en]

    This doctoral thesis is about child culture and status, power and social relations in everyday practice. The aim is to explore the everyday practice within the production of performing arts and problematize what is at stake in the practice with regard to child culture as an artistic field. The research focuses on how the everyday practice is organized, how status-power influences the practice, and lastly, the potential relevance that the everyday practice within the production of performing arts has for understanding child culture as an artistic field. 

    The thesis ethnographically explores the everyday practice of a theater. The fieldwork was performed in a section that produces performing arts for children and young people. The practice is analyzed and interpreted through the practice theory of Theodore Schatzki, Stephen Kemmis et al.’s methodological concept of practice architecture and Theodore Kemper’s theory on status-power. Other important concepts are child culture, culture and childhood. 

    The analysis shows the everyday practice as organized around an artistic objective that is simultaneously artistically and pedagogically oriented. This split orientation of the objective sets the section apart from the other artistic sections within the theater. The artistic objective generates important status for a production aimed at children and young people. However, compared to other sections within the institution, this section has differing material and economical prerequisites, which complicates, and sometimes obstructs, the process of asserting artistic status within the theater. The weaker material and economical arrangements underlines the importance of positive social relatings (Kemmis’ term), social status and the maneuvering of power-relations within the theater, in order to ensure artistic, technical and material resources. 

    The practice appears organized in a practice tradition that displays a firm artistic hierarchy, and this illuminates how what is understood as artistic rather than pedagogical or technical in nature always carries a higher status within the practice. This is significant in the work of the section, since large parts of their production are presented as pedagogical rather than artistic projects, and therefore generate lower artistic status. Yet, the analysis also shows a third kind of policy related status being generated by the production of the section. The section and its production is a central part of legitimizing the production of the theater regarding cultural policy, state bureaucracy and funding. Its production therefore upholds a kind of policy related status within the institution. 

    The analysis reveals three kinds of status in the practice, one social, one artistic and one related to cultural policy. The weaker power position and lower artistic status of child culture creates dependence of visibility within the theater. It also shows child culture and pedagogy as deeply intertwined phenomena, with pedagogy both diluting and obscuring the production of artistic status while simultaneously generating possibilities for the policy related kind of status within the institution. Thus while pedagogy can generate low artistic status, the analysis shows it can also be understood as creating a radical artistic potential within child culture as an artistic field.

  • Public defence: 2018-12-17 14:00 L30, NOD-huset, Kista
    Homem, Irvin
    Stockholm University, Faculty of Social Sciences, Department of Computer and Systems Sciences.
    Advancing Automation in Digital Forensic Investigations2018Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Digital Forensics is used to aid traditional preventive security mechanisms when they fail to curtail sophisticated and stealthy cybercrime events. The Digital Forensic Investigation process is largely manual in nature, or at best quasi-automated, requiring a highly skilled labour force and involving a sizeable time investment. Industry standard tools are evidence-centric, automate only a few precursory tasks (E.g. Parsing and Indexing) and have limited capabilities of integration from multiple evidence sources. Furthermore, these tools are always human-driven.

    These challenges are exacerbated in the increasingly computerized and highly networked environment of today. Volumes of digital evidence to be collected and analyzed have increased, and so has the diversity of digital evidence sources involved in a typical case. This further handicaps digital forensics practitioners, labs and law enforcement agencies, causing delays in investigations and legal systems due to backlogs of cases. Improved efficiency of the digital investigation process is needed, in terms of increasing the speed and reducing the human effort expended. This study aims at achieving this time and effort reduction, by advancing automation within the digital forensic investigation process.

    Using a Design Science research approach, artifacts are designed and developed to address these practical problems. Summarily, the requirements, and architecture of a system for automating digital investigations in highly networked environments are designed. The architecture initially focuses on automation of the identification and acquisition of digital evidence, while later versions focus on full automation and self-organization of devices for all phases of the digital investigation process. Part of the remote evidence acquisition capability of this system architecture is implemented as a proof of concept. The speed and reliability of capturing digital evidence from remote mobile devices over a client-server paradigm is evaluated. A method for the uniform representation and integration of multiple diverse evidence sources for enabling automated correlation, simple reasoning and querying is developed and tested. This method is aimed at automating the analysis phase of digital investigations. Machine Learning (ML)-based triage methods are developed and tested to evaluate the feasibility and performance of using such techniques to automate the identification of priority digital evidence fragments. Models from these ML methods are evaluated in identifying network protocols within DNS tunneled network traffic. A large dataset is also created for future research in ML-based triage for identifying suspicious processes for memory forensics.

    From an ex ante evaluation, the designed system architecture enables individual devices to participate in the entire digital investigation process, contributing their processing power towards alleviating the burden on the human analyst. Experiments show that remote evidence acquisition of mobile devices over networks is feasible, however a single-TCP-connection paradigm scales poorly. A proof of concept experiment demonstrates the viability of the automated integration, correlation and reasoning over multiple diverse evidence sources using semantic web technologies. Experimentation also shows that ML-based triage methods can enable prioritization of certain digital evidence sources, for acquisition or analysis, with up to 95% accuracy.

    The artifacts developed in this study provide concrete ways to enhance automation in the digital forensic investigation process to increase the investigation speed and reduce the amount of costly human intervention needed.


  • Public defence: 2018-12-18 10:00 Vivi Täckholm-salen (Q-salen), NPQ-huset, Stockholm
    Sigurlásdóttir, Sara
    Stockholm University, Faculty of Science, Department of Molecular Biosciences, The Wenner-Gren Institute.
    Influence of host and bacterial factors during Neisseria meningitidis colonization2018Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The human-restricted pathogen Neisseria meningitidis is a major cause of bacterial meningitis and sepsis worldwide. Colonization of the mucosal layer in the upper respiratory tract is essential to establish an asymptomatic carrier state and invasive disease. N. meningitidis encounters diverse environmental challenges during colonization and has evolved multiple strategies and virulence factors to survive and adapt within the host.

    Upon initial adhesion to the host epithelial cells, N. meningitidis forms pilus-mediated aggregates called microcolonies, which are characterized by interbacterial and host-cell interactions. Microcolonies promote long-term asymptomatic colonization within the host. However, the dispersal of single bacteria from microcolonies can help N. meningitidis to develop close contact with host cells and facilitate the invasion of mucosal surfaces or transmission to a new host.

    This thesis focuses on understanding how the interplay between the host, environment, and virulence factors influences N. meningitidis colonization. Paper I shows that the host-derived metabolite lactate induces rapid dispersal of N. meningitidis microcolonies. Further molecular characterization in Paper II revealed that lactate-induced dispersal is mediated by pilus retraction, occurs in a density-dependent manner, and is responsive to temperature. Paper III shows that the deletion of D-lactate dehydrogenase LdhA in N. meningitidis promotes aggregation and biofilm formation through an increase in the autolysis-mediated release of extracellular DNA. Finally, Paper IV examines the role of polynucleotide phosphorylase (PNPase) in the virulence of N. meningitidis. The deletion of PNPase resulted in a pilus-dependent increase in the aggregation and adhesion to epithelial cells. A PNPase mutant was growth deficient and highly attenuated in an in vivo mouse model. Transcriptional analysis revealed that PNPase plays a role as a major regulator in N. meningitidis.

  • Public defence: 2018-12-20 10:00 De Geersalen, Geovetenskapens hus, Stockholm
    Malafry, Laurence
    Stockholm University, Faculty of Social Sciences, Department of Economics.
    Inequality and Macroeconomic Policy: Essays on Climate, Immigration and Fiscal Intervention2018Doctoral thesis, monograph (Other academic)
    Abstract [en]

    This thesis consists of four self-contained essays in economics.

    Optimal Climate Policy with Household Wealth Inequality. Policy makers concerned with setting optimal carbon taxes to address climate change externalities often employ integrated assessment models (IAMs). While these models differ on their assumptions of climate damage impacts, discounting and technology, they conform on their assumption of complete markets and a representative household. In the face of global inequality and significant vulnerability of asset poor households, I relax the complete markets assumption and introduce a realistic degree of global household inequality. A simple experiment of introducing a range of global carbon taxes shows a household's position on the global wealth distribution predicts the identity of their most preferred carbon price.

    Immigration Shocks, Equilibrium Unemployment and Inequality. The purpose of this paper is to present a proof-of-concept model for assessing the impact of immigration shocks on a country's equilibrium unemployment, wages and inequality. The model implements labour market matching in the workhorse heterogeneous agent macro model with precautionary savings. In this setting, I perform several transition experiments exploring the channels and mechanisms through which a substantial immigration shock affects macroeconomic outcomes, including conditional welfare and economic integration. I find that the identity of the immigration cohort, as well as, features of the receiving economy matter for both the magnitude and direction of the response.

    Fiscal Multipliers in the 21st Century. Fiscal multipliers appear to vary greatly over time and space. Based on VARs for a large number of countries, we document a strong correlation between wealth inequality and the magnitude of fiscal multipliers. In an attempt to account for this finding, we develop a life-cycle, overlapping-generations economy with uninsurable labor market risk. We calibrate our model to match key characteristics of a number of OECD economies, including the distribution of wages and wealth, social security, taxes, and government debt and study how a fiscal multiplier depends on various country characteristics. We find that the fiscal multiplier is highly sensitive to the fraction of the population who face binding credit constraints and also to the average wealth level in the economy. These findings together help us generate a cross-country pattern of multipliers that is quite similar to that in the data.

    Fiscal Consolidation Programs and Income Inequality. Following the Great Recession, many European countries implemented fiscal consolidation policies aimed at reducing government debt. Using three different empirical approaches, we document a strong positive relationship between higher income inequality and stronger recessive impacts of fiscal consolidation. To explain this finding, we develop a life-cycle, overlapping generations economy with uninsurable labor market risk. We calibrate our model to match key characteristics of a number of European economies, including the distribution of wages and wealth, and study the effects of fiscal consolidation programs. We find that higher income risk induces precautionary savings behavior, which decreases the proportion of credit-constrained agents in the economy. Our model produces a cross-country correlation between inequality and the fiscal consolidation multipliers in line with the data.

  • Public defence: 2019-01-10 13:00 Högbomsalen, Geovetenskapens hus, Stockholm
    Pas Schrijver, Annemiek
    Stockholm University, Faculty of Social Sciences, Department of Human Geography.
    Pastoralists, Mobility and Conservation: Shifting rules of access and control of grazing resources in Kenya's northern drylands2019Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Pastoral mobility is seen as the most effective strategy to make use of constantly shifting resources. In northern Kenya, mobile pastoralism as a highly-valued strategy to manage grazing areas and exploit resource variability is becoming more complex. Policy and project implementation has historically been driven by the imperative to secure land tenure and improve pasture in bounded areas through State-led settlement schemes. Relatively recently, increased (inter)national interests in nature and wildlife conservation on community land in the northern pastoralist regions see conservation and development as crucial and urgent requirements for stimulating economic growth and security. This study presents the case of Samburu pastoral mobility within the context of such shifting social and environmental circumstances. It focuses on changing rules of access and control of livestock resources. These transformations are analysed in the context of the large-scale establishment of community conservancies and what role these conservancies play in the actual use and transformation of space for pastoralists. Empirically, this thesis is based on a total of eighteen months fieldwork including semi-structured interviews and observations in Samburu, Isiolo and Laikipia. It demonstrates how the principal of reciprocal access to pasture between pastoralists is giving way to conditional access based on membership of more formal, territory-based institutions such as community conservancies. It further shows how access to private land may be open for negotiation through the formation of grazing arrangements, which are also used to control pastoralists’ movements beyond enclosed land. In spite of a rhetoric acknowledging the multiple benefits of livestock mobility, current policy entails a continuation of past policy and project implementation where prescriptions still revolve around conservation enclosures and settlement politics. The thesis concludes that such processes of territoriality are likely to produce unexpected and potentially disappointing outcomes, while struggle and conflict persist.

  • Public defence: 2019-01-11 13:00 JMK-salen, Garnisonen, Stockholm
    Faggella, Chiara
    Stockholm University, Faculty of Humanities, Department of Media Studies.
    "Not So Simple": Reassessing 1951, G.B. Giorgini and the launch of Italian fashion2019Doctoral thesis, monograph (Other academic)
    Abstract [en]

    This dissertation aims to shed light on the circumstances that allowed Italy to become a reputable country of origin in the international fashion market. In particular, my contribution to the historiography of Italian fashion is a reassessment of the role played by Giovanni Battista Giorgini, whose involvement with the fashion and handicraft industries has not been fully investigated by scholars so far. Drawing upon Marc Bloch’s paradigm against the “fetish of the single cause”, I argue that the historiography of Italian fashion is not so simple and linear as it has been presented so far. Instead, the appearance of Giorgini’s Italian High Fashion Shows from 1951 needs to be contextualized with other historical facts. By outlining a populous scenario of different actors and concurring events, this dissertation breaks away from the simplistic notion of Italian fashion being born overnight in 1951.

    Chapter one discusses the ways in which the idea of an Italian look emerged in the US press already before the end of World War II, and identifies the linguistic and visual features that characterized these earliest reports. Chapter two discusses the contributions to the promotion of Italian fashion merchandise in the United States by Max Ascoli, an antifascist Italian émigré who moved to New York in the late 1930s. His philanthropic involvement with the Italian handicraft industry is discussed in order to understand how the US market's faith in Italian goods had to be restored in relation to the perceived quality of exported goods. Chapter three focuses on Giovanni Battista Giorgini, presents a critical overview of his biography and identifies his earliest attempts at promoting Italian products to US and Canadian markets. Particular emphasis is given to Giorgini's role as an employee of the Allied Forces during the Allied occupation of Florence, and to the overlapping vicissitudes of his work with an American touring exhibition, Italy at Work, initiated by Ascoli. Chapter four discusses the activities of Giorgini’s competitors in Italy, that is agencies, associations and individuals that were operating in postwar times to export Italian fashion in the United States. Chapter five finally discusses the organization of Giorgini’s Italian High Fashion Shows in Florence between 1951 and 1953, the organization of his business venture and the ways in which the Shows solidified earlier representations of Italian fashion in the US press, becoming a benchmark for years to come.

    This study concludes that the historicisation of Giorgini, and his contribution to the promotion of Italy as an independent, non-derivative fashion market for export, was made possible thanks to a larger network of transatlantic actors that, immediately after World War II, strove for the same business goals. Eventually, this dissertation provides a historical perspective that defies the simplistic categorization of the past in straight compartments, in this case blurring the margins between Fascist and liberated, democratic Italy.

    The full text will be freely available from 2020-01-11 09:00