Publikationer från Stockholms universitet
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Latent state estimation with longitudinal and adaptive measurements
No full textLatent variables are useful constructs for modeling states that cannot be directly observed, such as skills, attitudes and health states. Tests designed to measure latent scores often take the form of questionnaires. The developer of such a test aims to assemble a set of items that measures a latent state with good precision. A challenge is that the best set of items depends on the respondent’s true latent score, so a test optimized to give good precision for some respondents may be less precise for others. This dissertation explores statistical methods to optimize the measuring instrument through simulation studies and empirical applications to diverse populations. The papers included here evaluate adaptive methods that select items based on current knowledge about the respondent. Paper 1 proposes an adaptive method for selecting one item at a time in a Voting Advice Application. With a test that continuously selects the most informative next item, the respondent can conclude the session without answering all items and still get a result that is sufficiently accurate. The proposed method relies on Item Response Theory and a multidimensional latent construct. In Paper 2, we explored an adaptive model to measure the health states of patients evaluated for symptoms of Parkinson's disease. We compared this adaptive model to optimized static item sets designed for good population-average precision. The Parkinson's dataset consisted of repeated measurements across multiple timepoints, which required a longitudinal approach. In both Papers 1 and 2, the purpose of the methods was to enable more time-efficient versions of tests to increase usage. Papers 3 and 4 evaluate methods for tracking abilities that change over time. Unlike the Parkinson's scenario with a full test repeated at multiple timepoints, here we have only one observation per time point. In these settings, it is common to abandon traditional statistical models and instead rely on computationally inexpensive algorithms. Of these algorithms, the Elo rating system stands out as the most prominent. This rating system, developed to rate chess players, now has widespread use in many competitive sports and also in education. We identified limitations associated with the Elo method, and proposed extensions to remedy these. In Paper 3, we developed a hybrid approach that combines standard Elo with statistical modeling to incorporate group-level information. In Paper 4, we demonstrated that in a closed system in which students improve in ability, and where item difficulties are estimated in real time, the Elo method produces increasingly deflated ability estimates. We proposed a method to quantify and offset this system-level deflation
“I’m a tattoo artist when I go to bed, I’m a tattoo artist when I wake up”
No full textSyftet med studien är att få en fördjupad förståelse för hur tatueringsartister konstruerar sinyrkesidentitet i förhållande till status, deras sociala roller och deras hela identitet. Data har samlats ingenom semistrukturerade kvalitativa intervjuer med tatueringsartister som analyserats genom entematisk analys. Utifrån detta sorterades tatueringsartisternas uttalanden in i teman för att kunnaanalyseras och få en fördjupad förståelse av skapandet av deras yrkesidentitet. Teorier som används istudien är Bourdieus habitus och kapital, Charles Horton Cooleys spegeljag, Strykers symboliskainteraktionism och Stiers yrkesidentitet. Resultatet visar att tatueringsartisters yrkesstatus minskarutifrån fördomar och ekonomiska aspekter i relation till andra yrken, både i dess symboliska ochvolymbemärkelse. Fördomarna och ekonomiska aspekter påverkar yrkesstatusen, men hindrar inteskapandet av tatueringsartisternas yrkesidentitet, utan snarare förstärker den. Resultatet visar även attyrkesidentiteten påverkar många delar av tatueringsartisternas liv samt att yrket är mer än ett jobb. Själva yrkesutövningen kan genom det ses som en form av livsstil.This study aims to deepen the understanding of tattoo artists' construction of work identity in relationto their status, social roles, and entire identity. Semi-structured qualitative interviews facilitate thecollection of data, through which the thematic analysis stems. The analysis then uses Bourdieu'stheory of habitus and capital, Charles Horton Cooley's mirror-self, Stryker's symbolic interactionism,and Stier’s work-identity. Results show a decrease in status because of prejudice and economicaspects, in relation to other occupations, both symbolically and in volume. Despite a lower status, thetattoo artist work-identity persists and sort of thrives off this. Results also show the impact whichwork-identity has on several aspects of the tattoo-artists’ lives. The occupation becomes less thanwork, and more like a lifestyle
Moisture recycling in forest-agricultural systems : An interdisciplinary view within and across scales
No full textMoisture recycling is a hydrological process that captures the journey of water particles in the atmosphere - starting with terrestrial and oceanic evaporation, continuing with their windborne transport, and ending with precipitation back on land and ocean. Land cover affects the amount of recycled precipitation, and hence the ways we, as humans, use, manage, and govern land concern moisture recycling. Moisture recycling is scarcely managed and governed currently, despite being increasingly recognized as an important process in the biosphere, supporting our society. Moisture recycling is one of the many processes entangling forests and agriculture at various scales, as part of forest-agricultural social-ecological systems. Forests have the potential for securing precipitation for downwind agriculture, although the understanding of this process within the broader forest-agricultural systems remains limited and improving this understanding requires an interdisciplinary approach. As our biophysical understanding of moisture recycling progresses, a question arises: how can we use the knowledge of moisture recycling to guide our activities on land that safeguard forests and agriculture synergistically? The thesis attempts to answer this question by applying a social-ecological systems perspective and an interdisciplinary approach to investigate the interdependence between forests and agriculture through moisture recycling. By applying the forest-agricultural systems context and beyond, the thesis further assesses the need to govern moisture recycling as a mediating process in social-ecological systems. Five papers in this thesis cover different scales of social-ecological processes entangling forests and agriculture. Paper I analyzes moisture recycling at the national scale, to conceptualize its interconnection with forests, agricultural production, and crop trade across countries globally. Paper II focuses on the regional scale dynamics of moisture recycling and the role of forests as moisture sources during heatwaves in Europe. Paper III zooms in on the local scale to detect changes in local forests and shifting cultivation practices as a result of social-ecological pressures on land in the Democratic Republic of Congo. Paper IV complements Paper III with an investigation into the moisture recycling process connecting local forests with local agricultural practices. Finally, Paper V uses a futuring exercise to imagine the governance of moisture recycling as economic goods at diverse scales. Together, these papers suggest that forests support downwind agricultural production through the provision of precipitation within and across scales. This relationship is reciprocal, considering that forests are also influenced by the state of downwind agriculture through social dynamics. Accordingly, moisture recycling unravels a new way of interdependence between forests and agriculture. This thesis advances the moisture recycling knowledge beyond its biophysical aspects, and prompts us to reflect on what governing moisture recycling in the future would entail
Constructing Tawfan al-Aqsa : A Constructivist Analysis of the Framing and Construction of Identity, Norms, and Interests in Hamas’s Foreign Public Discourse (2023–2025)
No full textOn the morning of October 7, 2023, Hamas launched Operation al-Aqsa Flood, a large-scale military attack on Israel. This prompted a significant Israeli military response, and the start fo the longest war in the history of the Israeli-Palestinian conflict was a fact. Shortly after the attack, Hamas spoken statements, by the spokesman of the Qassam Brigades, Abu Obaida, and another by the Head of the Political Bureau, Ismail Haniyeh. These statements marked the start of Hamas’s foreign public discourse during the ongoing Gaza war. This thesis uses framing analysis and identity-construction analysis to examine eight Hamas speeches delivered between October 16, 2023, and the first prolonged ceasefire in January 2025. It explores how Hamas utilized discourse to construct identities and frame norms and interests during the war. Drawing on constructivist theory in International Relations and on theories of strategic identity construction and norm entrepreneurship, the analysis found that Hamas engaged in highly polarized discourse, constructing Israel as the “Other” while also appealing to universal and international law norms. It also employed a notable degree of religious language, including Qur’anic references and intertextual meanings where the war between Israel and Hamas is placed within a scriptural narrative. The thesis hence argues that Hamas acted as a norm entrepreneur, appealing to universal norms to gain greater international legitimacy and esteem among potential allies, while simultaneously maintaining religious elements to preserve legitimacy among its base.Morgonen den 7 oktober 2023 inledde Hamas en omfattande attack mot Israel under namnet Tawfan al-Aqsa Operationen. Som svar på attacken svarade Israel med ett brutalt bombardemang av Gazaremsan och början på det längsta kriget i den israelisk-palestinska konflikten var ett faktum. Kort efter attacken publicerade Hamas officiella uttalanden, från talesmanen för Qassam-brigaderna, Abu Obaida, och från ledaren för organisationens politbyrå, Ismail Haniyeh. Dessa uttalanden markerade början på det som utvecklades till Hamas offentliga utrikesdiskurs under det pågående Gazakriget. Denna uppsats använder gestaltningsanalys samt en analys av identitetskonstruktion för att analysera åtta Hamastal som hölls mellan den 16 oktober 2023 och den första långvariga vapenvilan i januari 2025. Uppsatsen kartlägger hur Hamas, genom sin offentliga utrikesdiskurs konstruerar identiteter och gestaltar normer och intressen under kriget. Med utgångspunkt i konstruktivistisk teori inom internationella relationer och teorier om strategisk identitetskonstruktion och normentreprenörskap fann analysen att Hamas begagnade sig av en starkt polariserad diskurs, där Israel konstruerades som den "Andre" samtidigt som genom gestaltning appelerar till universella och internationella rättsnormer. Hamas använde också en betydande grad av religiöst språk, inklusive Koranreferenser med intertextuella referenser. Uppsatsen argumenterar för att Hamas genom sin offentliga utrikesdiskurs agerat som en normentreprenör, genom att hänvisa till universella normer för att vinna större internationell legitimitet och respekt bland potentiella allierade, samtidigt som religiösa element behölls för att bevara legitimitet bland sina supportrar och bas
Handelsbodens betydelse för landsbygdens utveckling : En studie av fem kunders varuinköp från Håkanbols Handelsbod, Örebro Län, under åren 1903 till 1918 och hur detta speglar den svenska landsbygdens utveckling
No full textUtifrån outforskat bokföringsmaterial från Håkanbols Handelsbod i Örebro län, kopplar denna undersökning samman fem kunders varuinköp med den stora ekonomiska omvandling som Sverige genomgick 1903 till 1918. Landsbygdens ekonomiska transformation från självhushållning till marknadsbaserad varuhandel, i samband med ståndssamhällets upplösning, markerades av införandet av näringsfrihetsförordningen 1864. Ur de fem kundernas varukorgar har fyra nyckelprodukter: Förpackningar, Falukorv, Bröd, samt Kläder, studerats som indikatorer för moderniseringen av samhället. En tydlig ökning av de fyra nyckelprodukterna har påvisats vilket stärker studiens tes att utifrån ett mikrohistoriskt perspektiv skulle handelsbodens varuförsäljning kunna speglar den svenska ekonomiska utvecklingen under början av 1900-talet
Gangsterrappare: Missförstådda poeter eller våldsromantiker? : En kritisk diskursanalys av hur gangsterrappare positioneras och konstrueras i svenska mediesystem
No full textIcke används inte : En kartläggning av negationsanvändning på 1800-talet
No full textDen här uppsatsen undersöker med hjälp av en korpusanalys användningen av negationerna ej, icke och inte i texter från 1800-talet. Syftet är att kartlägga hur amvändningen av negationerna ser ut och hur den förändras från början till slutet av 1800-talet. I uppsatsen undersöks genre, tid och regional faktor som möjliga faktorer som påverkar vilken negation som används mest. Resultatet diskuteras med hjälp av sociolingvistiska teorier
Radiation Protection Perspectives in Emergency Preparedness
No full textWell-established emergency preparedness for radiological and nuclear events is essential for minimizing risks and consequences to public health, safety, and the environment. Such events may give rise to complex exposure scenarios that challenge existing frameworks for risk assessment, medical response, and decision-making, regardless of whether the incident is accidental or deliberate. Effective preparedness therefore requires technical capabilities for dose assessment, an integrated understanding of biological effects, training for relevant exposure scenarios, as well as a clear regulatory and organizational framework for emergency response. In addition to the technical and biological challenges addressed in the papers included in this thesis, emergency preparedness for radiological and nuclear events is strongly shaped by national legislation and regulatory frameworks issued by relevant authorities. The exercise of public authority, legal responsibilities, mandated roles during emergency situations, and coordination between agencies define how preparedness measures are implemented in practice and how response actions are initiated and managed. Radiological and nuclear events are governed by partly overlapping legal and organizational frameworks, which may complicate emergency preparedness and response. Radiological events are mainly handled within civil emergency preparedness structures, whereas nuclear events may require additional legal mechanisms related to national security and governmental decision-making. Moreover, the nature of the scenario, whether accidental or deliberate, may require involvement of law enforcement and other security actors, extending the scope of emergency response beyond radiation-related considerations alone. The overall aim of this licentiate thesis is to contribute to improved emergency preparedness for large-scale radiological and nuclear events by integrating technical, biological, and organizational perspectives. This aim is addressed through two complementary studies: one investigating the applicability of a biological dosimetry technique for exposure to mixed radiation fields, representative of those expected in nuclear emergency scenarios, and one assessing the consequences of a radiological dispersal scenario in an urban environment, with particular focus on the geographical distribution of radioactive contamination under varying local urban conditions. Together, these studies are placed within a broader framework of emergency preparedness, with particular attention to the Swedish regulatory and organizational context governing radiological and nuclear emergencies. The results show that both radiological emergency scenarios and nuclear-related exposure situations involve considerable complexity in terms of exposure patterns and dose assessment. The biological dosimetry study indicates that gene expression–based methods can provide useful information for retrospective dose assessment following mixed radiation exposures, supporting their potential application in large-scale triage situations. The radiological dispersal study shows that local conditions, such as urban landscape and meteorological factors, strongly influence the spatial distribution of radioactive contamination and potential population exposure. In large-scale emergency scenarios, the geographical extent of contamination can therefore have a significant impact on the selection of individuals for further medical examination. The findings of this thesis emphasise the importance of integrating technical assessments, biological dosimetry, and regulatory considerations in radiological and nuclear emergency preparedness. By addressing both consequence assessment and retrospective dose estimation, the work contributes knowledge that can support planning, decision-making, and prioritization of resources during large-scale emergency situations. The results may therefore provide analytical support to authorities and organizations involved in preparedness and response to radiological and nuclear emergencies
Spectral Geometry and Magnetic Fields on Quantum Graphs
No full textWe are interested in spectral geometry: the connection between the spectrum of certain operators and the geometry of the domain, as well as inverse problems: determining an operator from its spectrum. In this thesis two papers dedicated to Schrödinger operators on metric graphs are presented. A metric graph (similar to a discrete graph) consists of a set of vertices and a set of edges. But each edge is viewed as a real interval of some length. This gives a metric space structure. The (magnetic) Schrödinger operators on are self-adjoint operators acting on functions that are defined on the graph. Specifically they act as differential operators where are real valued functions. We view as an (electric) potential and as a magnetic potential on . Any Schrödinger operator on a metric graph is determined by the potentials and the vertex conditions describing the domain. The first paper gives an interpretation of the Colin de Verdière parameter in the context of metric graphs. The original Colin de Verdière parameter for discrete graphs is a number that gives topological information about the graph, such as whether the graph is planar or not. It is defined as the maximal multiplicity of the second eigenvalue for a class of matrices, associated with the graph, called Colin de Verdière matrices. The second paper is about Ambarzumian type theorems for metric graphs. These are theorems that show that a certain exceptional operator, in a family of operators, is uniquely determined by its spectrum. E.g. any Schrödinger operator with non-zero electric potential will have different spectrum than a Laplacian (i.e. an operator with potential equal to 0), provided the vertex conditions are standard. In the article it is shown how some Ambarzumian type theorems can be generalized to not only include the electric potential, but also a magnetic potential. This is the first time magnetic potential has been included in an Ambarzumian type theorem.