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  • Public defence: 2019-01-25 10:00 Vivi Täckholmsalen (Q-salen), NPQ-huset, Stockholm
    Erlandsson, Rasmus
    Stockholm University, Faculty of Science, Department of Zoology.
    Spatial and temporal population dynamics in the mountain tundra – mesopredator and prey2019Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    It is well known that competition, predation and fluctuating food resources can have strong effect on individual fitness and population dynamics. The complexity of natural systems can make it complicate to disentangle those processes, but environments with relatively simple food webs, and strong cyclic population dynamics offer contrasting conditions resembling experimental treatments. This thesis concerns the spatial and temporal implications of fluctuations in small rodent abundance on two trophic levels in a highly cyclic ecosystem, the Scandinavian mountain tundra. The first two chapters focus on plant biomass and spatiotemporal distribution in the Norwegian lemming (Lemmus lemmus), while the three last papers focus on the direct and indirect effects of small rodent fluctuations and territory quality on reproductive success, juvenile survival and group living in a lemming specialist mesopredator, the arctic fox (Vulpes lagopus). By developing, validating and applying a novel application of aerial photos for remote sensing of plant biomass (Chapter I), we found that food availability predicted lemming distribution during population peaks, but that they were more habitat specific during increase years when intraspecific competition was lower (Chapter II). Arctic fox reproduction is tightly connected to small rodent abundance but the effects of geographical variation in food availability is less well known. We used 17 years of population surveys of an arctic fox subpopulation in mid Sweden (Helagsfjällen) to investigate potential effects. During small rodent increase years, we found that arctic fox litter sizes were smaller in territories of intermediate plant productivity, compared to both more and less productive territories (Chapter III). This could be an effect of limited food availability together with increased presence of red foxes (Vulpes vulpes), a stronger and potentially lethal competitor. However, when small rodents peaked, and competition would be expected to decrease, we saw no effect of territory productivity. Based on a smaller data set concerning juvenile summer survival, we found that the mortality rate among juveniles born by first time breeding arctic fox females were more sensitive to low small rodent prey abundance (Chapter IV). We explain it with an increased predation pressure from top-predators that switch from small rodents to alternative prey when small rodents decline, as suggested by an observed positive effect on juvenile survival by adult presence on den sites. Arctic foxes are socially flexible, and several adults can share a den with the resident pair, potentially increasing juvenile survival and help in territorial defence. Returning to the 17-year data set, we tested the Resource Dispersion Hypothesis predicting that increased resource availability should increase group size (Chapter V). We found support for this prediction as group living increased during the small rodent peak phase. However, it remained unexpectedly high during the decrease phase, when resources are scarce. This could however be related to increased predation pressure, and an increasing benefit of group living.

  • Public defence: 2019-01-25 10:00 De Geersalen, Geovetenskapens hus, Stockholm
    Dunker, Rickard
    Stockholm University, Faculty of Law, Department of Law.
    Lokala ordningsföreskrifter2019Doctoral thesis, monograph (Other academic)
    Abstract [en]

    In Sweden there are more than 280,000 known ancient and historical remains and monuments (fornminnen), almost 17,500 protected natural areas, 48 certified airports, hundreds of ports and marinas and a very large number of geographical areas which constitutes so-called public place (offentlig plats) or are subject to shoreland protection (strandskydd). For each and every of these places, municipalities and/or some state administrative authorities may issue local ordinances on public order (lokala ordningsföreskrifter), i.e. additional local rules about what persons in the area have to observe concerning “the order” therein. This regulatory power has been used to regulate a wide range of different issues, e.g. consumption of alcohol, diving, gambling, skiing, Christmas decorations, fishing, running, collection of money, parking, supervision over cats, dogs and horses, placarding, demonstrations, photographing, camping, riding, golfing, marketing, barbecuing, boating, begging, moviemaking, goldpanning, climbing, leafleting, taxi services, cycling, smoking and hunting. It also happens that municipal servants or police officers are given extra powers through the local ordinances, e.g. a right to take certain measures against those who do not comply with the rules or to confiscate or forfeit property used in violation with the local decrees.

    The described arrangement and the examples raises many questions, e.g. whether all of these matters actually, with respect to the rest of the legal system, may be handled in local ordinances? If not, what can be regulated? Is there any supervision over the regulatory powers in question, for example whether the provisions are given a legal and appropriate content? How are the ordinances brought to the public's attention? Can the rules be subject to appeal and, if so, by whom and in what order? How do different ordinances regarding public order relate to each other in such geographic areas where they overlap? In this dissertation, this – the Swedish system with local ordinances on public order – is subject to a broad scientific examination.

  • Public defence: 2019-01-25 10:00 sal 14, hus 5, Kräftriket, Stockholm
    Nedic, Mitja
    Stockholm University, Faculty of Science, Department of Mathematics.
    On Herglotz-Nevanlinna functions in several variables2019Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    In this thesis, we investigate different aspects of the class of Herglotz-Nevanlinna functions in several variables. These are holomorphic functions on the poly-upper half-plane having non-negative imaginary part. Our results are presented in the four research articles A1 - A4, which are included in this thesis.

    Articles A1 and A2 establish a characterization of Herglotz-Nevanlinna functions in terms of an integral representation formula. The case of functions of two complex variables is presented in article A1, while the general case is treated in article A2, where different symmetry properties of Herglotz-Nevanlinna functions are also discussed.

    Article A3 discusses, in detail, the convex combination problem for Herglotz-Nevanlinna functions. This problem asks us to relate the representing parameters of different Herglotz-Nevanlinna functions under the assumption that these functions are related in a very particular way involving the convex combination of several independent variables. A related class of boundary measures is also discussed.

    Article A4 investigates the properties of Nevanlinna measures with respect to restrictions to coordinate orthogonal hyperplanes and the geometry of the support. A related class of measures on the unit poly-torus is also considered.

    Furthermore, this thesis is supplemented by three additional publications concerning Herglotz-Nevanlinna functions in one variable, related topics and applications.

    Article B1 concerns a particular class of convolution operators on the space of distributions that generalizes the well-studied class of passive operators. Article B2 introduces the class of quasi-Herglotz functions and discusses their integral representations, boundary values and sum-rules, as well as their applications in connection with convex optimization. Finally, the summary book-chapter C1 provides a general overview of the applications of Herglotz-Nevanlinna functions in electromagnetics.

  • Public defence: 2019-01-25 10:00 William-Olssonsalen, Geovetenskapens hus, Stockholm
    Fredriksson, Daniel
    Stockholm University, Faculty of Social Sciences, Department of Sociology.
    Enabling employment?: Drivers and outcomes of active labour market policies in comparative perspective2019Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis includes three empirical studies that analyse driving forces and outcomes of active labour market policies (ALMP) in comparative perspective. Whereas previous comparative research has largely relied on broad conceptualisations of ALMP, often considering policies such as public employment services and training programs as one single type of intervention, the studies in this thesis instead analyse more fine-grained categories and classifications of ALMP. By doing so, the studies contribute with nuance to the discussion of what has shaped labour market policies, and how these influence labour market outcomes.

    Study I: This study focuses on determinants of spending on public employment services (PES). Contrary to common assumptions, which state that PES is largely determined by structural factors, the main hypothesis is that partisan politics is a relevant predictor of PES spending. The analysis includes 17 welfare states between 1985 and 2011. The results indicate that partisan politics and electoral competition are related to the development of PES spending, but that the turn to activation in many welfare states in the late 1990s reduced the salience of partisan politics.

    Study II: This study analyses whether different types of active labour market policies are related to reduced unemployment, and especially if there is evidence for interdependencies between policies. The study distinguishes between public employment services (PES), training, and job creation programs. PES is singled out as a crucial factor that mediates the effects of other labour market policies, both active and passive. The study examines 19 welfare states between 1985 and 2012 and the results indicate that training programs reduce unemployment in the short run, whereas long-term effects are less apparent for all policy types. Increased investment in PES is found to strengthen the impact of training and job creation programs.

    Study III: This study examines the link between active labour market policies and transitions to employment from unemployment and inactivity across the European Union between 2003 and 2013. The study distinguishes between three types of interventions: core programs, directed towards the registered unemployed; peripheral programs, targeting the inactive part of the working age population; and mixed programs, targeting both groups. The results indicate that ALMP have beneficial effects on employment transitions among both the unemployed and the inactive, but that effects differ depending on the type of intervention. Unemployed seem to benefit from increased efforts on ALMP regardless of the type of intervention, whereas the inactive seem to have increased chances to transition into employment if programs target both groups, but not if interventions solely target the inactive.

  • Public defence: 2019-01-25 13:00 L 70, NOD-huset, Kista
    Holmberg, Jörgen
    Stockholm University, Faculty of Social Sciences, Department of Computer and Systems Sciences.
    Designing for added pedagogical value: A design-based research study of teachers’ educational design with ICT2019Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    In an increasingly digitized world teachers are expected to take on the role of educational designers and use ICT to design in ways that add pedagogical value to teaching and learning. This thesis adopts a design-based research (DBR) approach to: (a) explore and contribute to the educational design processes of teachers of English as a foreign language in their efforts to use ICT for added pedagogical value, (b) examine how ICT is used in educational designs to create/contribute to what the teachers and students describe as added value and (c) explore, problematize and refine DBR as a research approach.

    Literature studies and a collaborative self-study preceded the DBR to guide its focus and implementation. The DBR was carried out over a period of two years in four upper secondary schools in Sweden in which every student had access to their own computer. The research data consists of: (a) audio recorded design conversations, (b) enacted educational designs and design elements as parts of these, (c) reflective log entries written by the participating teachers, (d) focus group interviews with students and (e) the researcher’s field notes.

    Six different theoretical frameworks and models are used in combination in the accompanying articles to analyze the data and achieve the three research aims. The findings show how teachers’ pedagogical reasoning and TPACK development are interconnected and reciprocal aspects of the educational design process and how the externalization of, and reflection on, these aspects is necessary to develop the specific and practical TPACK needed to realize design intentions in situated contexts. A number of challenges and opportunities in the educational process have been identified.

    Moreover, the findings show how ICT was used to contribute added value in educational designs by facilitating: (a) more authentic and seamless learning experiences in external online contexts with both in-class and out-of-class actors irrespective of time and place, (b) an exchange of digital knowledge representations of understanding and practice between different actors, e.g. for the purposes of modelling, supporting cognitive apprenticeship, meta-cognitive self-regulation and formative assessment and (c) new and extended forms of, and opportunities for, collaborative creation and meaning-making.

    The current common focus in DBR on the development of prescriptive design principles is problematized in relation to the findings of the thesis, which illustrate the complex and situated nature of the educational design process. A theoretically and empirically informed design framework (DF) is developed and used as a conceptual tool to guide and analyze educational design processes and enactments. The findings illustrate how the use of the DF and the process of collaborative design reflection contributed to the analysis of the teachers’ design intentions and de facto design practices and to a DBR format that allowed the participants to use their respective competencies in the development of educational designs for added value. The thesis thereby serves as an example of how DBR can be methodically implemented to study and generate increased knowledge about teachers’ design intentions and design practices, develop research-based educational designs in line with teachers’ pedagogical intentions and support their development as educational designers.

  • Public defence: 2019-02-01 13:00 FB55, AlbaNova universitetscentrum, Stockholm
    Bjørgen, Johan Pires
    Stockholm University, Faculty of Science, Department of Astronomy.
    The synthetic chromosphere: Results and techniques with a numerical approach2019Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Realistic numerical simulations of the solar atmosphere can be used to interpret different phenomena observed on the solar surface. To gain insight into the atmospheric physical conditions, we compare the observations with 3D radiative magnetohydrodynamic models combined with forward modeling (radiative transfer). This thesis focuses particularly on the less understood chromospheric layer between the photosphere and the transition region. Only a few and complex spectral lines can probe the chromosphere making its observations a real challenge.The chromospheric environment is strongly influenced by departures from local thermodynamic equilibrium (non-LTE), horizontal radiative transfer (3D effects), and partially-coherent scattering of photons (partial redistribution effects). All these effects make the detailed 3D non-LTE radiative transfer very computationally demanding.In paper I, we focus on increasing the efficiency of non-LTE modeling of spectral lines in realistic solar models. We implemented a non-linear multigrid solver into the Multi3D code and showed that the method can handle realistic model atmospheres produced by radiative-MHD simulations. We obtained a speed-up of a factor 4.5-6 compared to multilevel accelerated lambda iteration.In paper II, we studied the chromospheric resonance lines Ca \textsc{ii} H\&K. Understanding their formation is crucial to interpreting the observations from the new imaging spectrometer CHROMIS, recently installed at the Swedish 1-m Solar Telescope. We investigated how the synthetic observables of Ca \textsc{ii} H\&K lines are related to atmospheric parameters.In paper III, we investigated a simulated active region including flux emergence that produced a flare. We modeled strong chromospheric lines, such as Ca \textsc{ii} H\&K, 8542 \AA, Mg \textsc{ii} h\&k, and H-$\alpha$, to investigate how it appears in synthetic images and spectra.

  • Public defence: 2019-02-06 10:00 Magnélisalen, Kemiska övningslaboratoriet, Stockholm
    Etman, Ahmed S.
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Aqueous Exfoliation of Transition Metal Oxides for Energy Storage and Photocatalysis Applications: Vanadium Oxide and Molybdenum Oxide Nanosheets2019Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Two-dimensional (2D) transition metal oxides (TMOs) are a category of materials which have unique physical and chemical properties compared to their bulk counterparts. However, the synthesis of 2D TMOs commonly includes the use of environmental threats such as organic solvents. In this thesis, we developed environmentally friendly strategies to fabricate TMO nanosheets from the commercially available bulk oxides. In particular, hydrated vanadium pentoxide (V2O5∙nH2O) nanosheets and oxygen deficient molybdenum trioxide (MoO3-x) nanosheets were prepared.  The V2O5∙nH2O nanosheets were drop-cast onto multi-walled carbon nanotube (MWCNT) paper and applied as a free-standing electrode (FSE) for a lithium battery. The accessible capacity of the FSE was dependent on the electrode thickness; the thickest electrode delivered the lowest accessible capacity.  Alternatively, a composite material of V2O5∙nH2O nanosheets with 10% MWCNT (VOx-CNT composite) was prepared and two types of electrodes, FSE and conventionally cast electrode (CCE), were employed as cathode materials for lithium batteries. A detailed comparison between these electrodes was presented. In addition, the VOx-CNT composite was applied as a negative electrode for a sodium-ion battery and showed a reversible capacity of about 140 mAh g-1. On the other hand, the MoO3-x nanosheets were employed as binder-free electrodes for supercapacitor application in an acidified Na2SO4 electrolyte. Furthermore, the MoO3-x nanosheets were used as photocatalysts for organic dye degradation. The simple eco-friendly synthesis methods coupled with the potential application of the TMO nanosheets reflect the significance of this thesis in both the synthesis and the energy-related applications of 2D materials.

  • Public defence: 2019-02-08 10:00 Magnélisalen, Kemiska övningslaboratoriet, Stockholm
    Cichocka, Magdalena Ola
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Unraveling the structures of complex nanocrystalline materials by combining TEM and XRPD – development and application2019Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Knowledge of the three-dimensional (3D) atomic structure of materials is essential to a fundamental understanding of their properties. The key to understanding the functionality of many materials, particularly those of commercial and industrial interest, is often hidden in the details at the nanoscale. For this reason, it is very important to choose the right strategy to analyze the structure of challenging materials with complex disordered framework structures, or of the layered materials that are the subject of this thesis. Structure analysis of beam-sensitive or uniquely disordered materials can be complicated. Although there are already existing methods such as X-ray powder diffraction (XRPD), the data may exhibit reflection overlap or other problems that make structure determination difficult. To overcome these limitations for nanocrystalline materials, complementary characterization techniques can be used. Here, I will focus on 3D electron crystallography (continuous rotation electron diffraction and high-resolution electron microscopy) methods that have grown during the past years as hybrid methods for structure determination. Based on the presented materials, I will also emphasize that any kind of challenges can be a driving force for method development.  Furthermore, some of the insights gained lead to better understanding of how to collect and process 3D electron diffraction data, which could be applied to make data collection of challenging samples easier and obtain higher quality structure refinements from the data. Finally, I will try to describe the general procedures for ab initio structure elucidation of disordered nanocrystals and layered materials.

  • Public defence: 2019-02-08 13:00 sal FB54, AlbaNova universitetscentrum, Stockholm
    Kundu, Esha
    Stockholm University, Faculty of Science, Department of Astronomy.
    Radio emission from supernovae2019Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis presents the modeling of radio and X-ray emissions from supernova (SN) shock fronts and hydrodynamical simulations of SN-circumstellar medium (CSM) interaction. The interaction of SN ejecta with the CSM drives a strong shock wave into the CSM. These shocks are ideal places where effective particle acceleration and magnetic field amplification can take place. The accelerated relativistic particles, in the presence of magnetic field, could emit part of their energy via synchrotron radiation in radio wavelengths. The flux of this radiation, when compared with observations, gives an estimate of the CSM density. This could either be the particle density (nISM) in case of the SN exploding in a constant density medium, characteristic of interstellar medium, or pre-SN mass loss rate (dM/dt) of the progenitor system for a wind medium. In Paper I we have modeled the synchrotron emission and compared that with the radio upper limits measured for the Type Ia SNe 2011fe and 2014J. Assuming equipartition of energy between electric and magnetic fields, with 10% of the thermal shock energy in each field, we obtain a very low density medium, having nISM <~ 0.35 cm-3, around both the SNe. In terms of dM/dt this implies an upper limit of 10-9 Msun yr-1 for a wind velocity, vw, of 100 km s-1. This study suggests that in SN shocks it is more likely that the amplification efficiency of magnetic fields is less than that for the electric fields. In Paper II, we carry out the hydrodynamical simulations of the interaction between SN ejecta and CSM for SN 1993J and SN 2011dh. Subsequently, the radio and X-ray emission have been calculated from the shocked gas encapsulated between the forward and reverse shocks. Considering the ejecta profile of these SNe from multi-group radiation hydrodynamics simulation (STELLA), it is found from our investigation that for a wind velocity of 10 km/s around 6500 years prior to the explosion of SN 1993J a change in mass loss rate occurred in the system. For a binary system this may imply that the change in dM/dt could be due to a change in the mass accretion efficiency of the companion star. In case of SN 2011dh the late time emission is turned up to be consistent with a wind medium with (dM/dt)/vw = 4 × 10-6 Msun yr-1/10 km s-1. Paper III focuses on the radio emission from four young SNe Type Ia, SN 2013dy, SN 2016coj, SN 2018pv and SN 2018gv. Using the same model for radio emission as in Paper I, the upper limits on dM/dt and nISM are estimated. We found tenuous media around these SNe, which put tight constrain on their progenitor systems.

  • Public defence: 2019-02-08 13:00 William-Olssonsalen, Geovetenskapens hus, Stockholm
    Sandman, Tua
    Stockholm University, Faculty of Social Sciences, Department of Political Science.
    The dis/appearances of violence: When a 'peace-loving' state uses force2019Doctoral thesis, monograph (Other academic)
    Abstract [en]

    The research problem that this dissertation addresses is how and with what implications the use of force in ‘distant’ places is made seen and known at home. As practices change and ‘peacework’ is becoming increasingly violent, the book argues that it is imperative to examine how war ‘comes home’ and to what extent the narratives emerging in public discourse open up for public reflection and (re)consideration. As the representation of violence varies between contexts and over time, the book contributes to ongoing debates on the representation of war and violence by offering a comprehensive and systematic examination of the representation of violence in the case of Sweden, where the engagement in war(like) activities by no means is considered normal. Though Sweden during the last decades has increased its contributions to operations of peace-enforcement, Sweden still projects an image of itself as a nation of peace and a nation at peace. Thus, Sweden could be considered a ‘most likely case’ for politicisation and dislocation once Swedish soldiers engage in violence.

    Drawing on poststructuralist theorisation on the political, processes of identification and the articulation of foreign policy as well as previous literature on the representation of war and violence, the book examines and conceptualises how violence dis/appears in Swedish public narratives at the time of Swedish military contribution to war(like) engagements. Part II of the book examines the representation of violence in Swedish parliamentary debates during, altogether, five military interventions taking place between 1960 and 2014. Part III takes a closer look at public service media material during three critical episodes that could be considered (potentially) dislocatory experiences related to the use of force. For the study of how violence dis/appears, the book advances a conceptual framework that combines the concepts of in/visibilisation, de/naturalisation and dis/identification. The study uncovers how the narratives on peace-enforcement move between making visible and making invisible, between problematisation and naturalisation, and between linking and differentiating the use of force to or from Sweden. It lays bare a number of narrative themes and responses that are salient over time, and examines the political work of the dis/appearances of violence in terms of de/stabilising the link between identity and policy, and in terms of de/politicising the issue of using force. Ultimately, the book argues that the dis/appearances of violence in public discourse condition the possibility for critical reflection and (re)consideration at home at the time of war(like) engagements abroad.