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Coming dissertations at Uppsala university

  • Time for Hyperons : Development of Software Tools for Reconstructing Hyperons at PANDA and HADES Author: Jenny Regina Link: Publication date: 2022-01-14 08:19

    The PANDA experiment at FAIR offers unique possibilities for performing hyperon physics. The detector will enable the reconstruction of both hyperon and antihyperon, which will be created together in proton-antiproton collisions. This enables investigations of the strong interaction in the non-perturbative regime. Due to their relatively long-lived nature, the hyperons impose a particular challenge on the track reconstruction and event building. In order to exploit the large expected reaction rates to the fullest, PANDA will utilize a fully software-based event filtering. Therefore, reconstructing hyperons for such a filter requires online track reconstruction that can handle particles created a measurable distance away from the interaction point and, at the same time, operate on free streaming data is needed. Until antiprotons are available at PANDA, a part of the hyperon program can be carried out with the predecessor, PANDA@HADES using a proton beam. 

    In this thesis, investigations of the detector signatures from the decay channels Λ → -, Ξ- → Λπ- and Ω- → Λ K-  produced in      →      reactions are presented. The detector signatures guide the subsequent track reconstruction algorithms. A candidate for online track reconstruction algorithms on free streaming data based on a 4D Cellular Automaton has been developed and is benchmarked. It utilizes information from the PANDA straw tube tracker and is agnostic to the point of origin of the particle. The track reconstruction quality assurance procedure and results from the tracking at different event rates are also presented. Finally, extrapolation algorithms for including hit information from additional detectors in the tracks are outlined. 

    In order to maximize the potential of the predecessor experiment PANDA@HADES, a kinematic fitting procedure has been developed for HADES that combines geometric the decay vertex information of neutral particles and track parameters such as momentum. Benchmark studies on simulated data from the channel p(3.5 GeV)p → ΛK+p are presented as well as tests of the kinematic fit on experimental data from 2007.

  • Stadens gränsplatser : Kungliga Poliskammaren och vardagens omstridda rum i Stockholm, 1776–1835 Author: Tobias Osvald Link: Publication date: 2022-01-14 08:12

    This dissertation explores the interaction between the inhabitants of Stockholm and the constables of the Royal Police Chamber—Sweden’s first police force—during a period in the city’s history that is associated with stagnation from the perspectives of demography and economy. The aim is to understand how space was negotiated and changed over time through everyday interactions and practices. The central question is why certain places in the urban space of Stockholm were contested. 

    The investigation is carried out through three thematic parts. Each part investigates kinds of disorder that exhibited clear elements of spatial contestation: homelessness, pub keeping, and sanitation. Each theme is explored by considering the cases that occurred in 1776–1777, 1804, and 1835. On an empirical level, the dissertation provides new information about the practices exercised in the meeting between Stockholm’s population and its agents of order. On a more abstract level, the dissertation engages critically with and adds to current theoretical perspectives on cities and spatiality. The interaction between the ideas and reality of urban space is clarified. Suggestions are made on possible approaches to studies of cities of comparable size and in a similar period.

    The answer to the central question—why certain places within the urban space of Stockholm were contested—is that they were border or peripheral places. At these places, the ordered city was mainly under threat and negations could occur. Rather than an unchanging city due to stagnation, a dynamic city with micro-geographies that changed in several ways is shown.

    The dissertation exposes previously underexplored depths of the studied time period. Households became smaller and excluded people who took to the city by “rough sleeping”. Pubs and similar drinking establishments became more distinguished from private homes and less mobile in the urban space. The flows of uncleanliness became more controlled and directed away from the public sphere of the streets. A central result is that an urban space consisting of porous boundaries and general transgressions gave way to one of hardened and more stabilized borders. Contestation and negotiations about borders moved where these were placed in Stockholm. Small, everyday geographies shifted and became more well-organized and closed. The boundaries of the city became, over time, clearer and more essential to keep. New border places arose and old ones were reshaped. By analyzing the practices of the city’s inhabitants and police force, it is apparent how an urban space became atomized.

  • Dihte gievrie – det vi möter i respekt : Berättelser om en sydsamisk trumma Author: Åsa Virdi Kroik Link: Publication date: 2022-01-13 09:49

    In 2010, five people made an unusual find: an old gievrie, a South Sami drum. They found it in the landscape near the village of Røyrvik, in the Norwegian part of Saepmie, close to the national border with Sweden. According to Norwegian law, such a find should be reported, and the item handed over to the authorities. But the group left it where it was found. A process then started that led to a three-way agreement between the authorities of Norway, the Sami parliament, and the local Sami association, before the gievrie was handed over to a museum, the Vitenskabsmuseet, in Trondheim. It is still kept there today, in a storeroom, more than eleven years after the discovery. In this dissertation I use Indigenous Research Methodology, an approach that I find corresponds to the methods developed in local Sami centers during recent decades. It is a method where the local Sami people are involved in all parts of the research process from initiation to completion, and where the final outcome must also benefit them.

    Discussions with Sami people in the area and stories told by them reveal that the landscape lives and that the drum, the rock it was found in, and the ancestors connected to them have their own agency – a relational worlsview – meaning that as much as possible about their will must be investigated before any decision can be taken about whether the drum should be moved from its place of discovery. Because of a history of oppression, marginalization, and mistrust, and due to differences in culture, the Sami are hesitant to discuss these matters in public. But, silence is also significant for other reasons, apart from being situated in a subordinated position in relations of power. Not having a language for the issues in concern, not having any answers, culturally significant non-verbal communication instead of spoken language, a will to exclude unwanted participants: these are also reasons and methods. Western education is based on text while Sami training to a great extent is non-spoken and transmitted the same way. These differences keep the two discourses apart.