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Via universitetsbibliotekets databas över doktorsavhandlingar kan du söka publicerade doktorsavhandlingar vid Göteborgs högskola/universitet från 1902 och framåt. Databasen innehåller också information om kommande disputationer.

UB:s databas över doktorsavhandlingar

Kommande disputationer

Microbial communities in anammox and nitrifying biofilms

[2017-09-19] Title: Microbial communities in anammox and nitrifying biofilms Authors: Suarez, Carolina Abstract: Excess of nitrogen in water bodies causes eutrophication. One important source of nitrogen is the effluent from wastewater treatment plants (WWTPs). Nitrogen in wastewater is most commonly removed by nitrification-denitrification. During nitrification-denitrification, aerobic ammonia oxidizing bacteria (AOB) oxidize ammonium to nitrite, which is in turn oxidized to nitrate by their syntrophic partners; aerobic nitrite oxidizing bacteria. Heterotrophic denitrifiers can then convert the nitrate to harmless nitrogen gas. Partial-nitritation anammox (PNA) is an alternative process for nitrogen removal which is today used for treatment of warm and concentrated sidestreams (reject water after anaerobic sludge digestion) at WWTPs, with potential to be used also for the mainstream of wastewater. PNA relies on bacteria capable of anaerobic ammonium oxidation (anammox) using nitrite as electron acceptor. Together with AOB they convert ammonia to nitrogen gas. To increase retention of biomass in bioreactors, bacteria are often grown in biofilms, microbial communities attached to a surface. The overall aim of this thesis was to study nitrifying- and anammox communities in biofilms, using moving bed biofilm reactors as a model system. Reactor performance, microbial community dynamics and biofilm structure of PNA reactors operated a low temperature or low ammonium concentration were studied, showing community stability, but process instabilities. Differences in composition and ribosomal content between reject- and mainstream communities were investigated, showing that both abundance and bacterial activity are important for explaining differences in process rates. Basic question about biofilm ecology were also studied. Here, for the first time, predation of anammox bacteria in biofilms was demonstrated. Furthermore, it was shown how biofilm thickness influences nitrifying communities and biofilm functions, with differences in community composition and ecosystem function. Together these results help to unravel the link between community composition and bioreactor function for anammox and nitrifying biofilms, which can lead to development of new technologies and strategies for N-removal in wastewater.

Fritidshem eller servicehem? En etnografisk studie av fritidshem i tre socioekonomiskt skilda områden

[2017-09-18] Title: Fritidshem eller servicehem? En etnografisk studie av fritidshem i tre socioekonomiskt skilda områden Authors: Andishmand, Catarina Abstract: In recent decades there has been decreased resources and larger groups of children in the leisure-time centres. Statistics show major differences between leisure-time centres in terms of staff education, group size, staffing levels and the number of children enrolled at each leisure-time centre. The overall aim of the thesis is to study social practices in leisure-time centres providing after-school care. Based on Anthony Giddens' theory of structuration, an ethnographic study was conducted of everyday life at leisure-time centres in three socio-economically diverse areas. Fieldwork was conducted at each leisure-time centre over the course of one semester. The study shows how children and adults talk about their neighbourhoods and schools. It also shows the actors notions about the mission of the leisure-time centres, expressed through the actors' talk and interactions, their day-to-day routines and everyday social encounters. In conclusion, the study shows that the geographic location, resources, staff skills, group sizes and children's socio-economic backgrounds together play major roles in the social practices and activities organised at the leisure-time centres. The social changes and developments of recent decades are noticeable in all leisure-time centres. Housing segregation along with freedom of school choice all had consequences for the leisure-time centres. For children attending the same leisure-time centres, the groups become increasingly homogeneous in line with the children's ethnic and socio-economic backgrounds. The results also show that leisure-time centres with large groups of children have reduced opportunities to provide a good learning environment. It becomes evident that the social practices in the leisure-time centres reproduce the contextual conditions, and risk reproducing structural differences in children's lives.

Power Outages, Increasing Block Tariffs and Billing Knowledge

[2017-09-16] Title: Power Outages, Increasing Block Tariffs and Billing Knowledge Authors: Meles, Tensay Hadush Abstract: Preferences for Improved Electricity Services in Developing Countries: Household’s Defensive Behavior and Willingness to Pay Access to electricity has received much attention but its reliability has been given less focus. Thus, uninterrupted power supply remains a critical challenge facing households in low-income developing countries. In this paper, we use data on household defensive expenditures and willingness to pay (WTP) to analyze households’ preference for improved electricity supply. We provide an estimate of average monthly defensive expenditures at different monthly hours of power outages using the generalized propensity score method – a continuous treatment matching. Furthermore, we elicit households’ willingness to pay for improved electricity supply using the contingent valuation method. To this end, we use a field survey data from 1,152 sample households in Addis Ababa, Ethiopia. Our results show that the estimated average monthly defensive expenditures is substantial and vary by the monthly hours of power outages. Also, results from the stated preference study show that households are willing to pay 19%–25% of the existing average monthly bill for improved electricity supply. JEL Classification: C21, D12, L94, N77, Q41, Q51 Keywords: Power outages, defensive behavior, willingness to pay, Ethiopia, generalized propensity score Do Consumers Respond to Marginal Prices of Electricity under Increasing Block Tariff? In developing countries, electric and water utilities commonly use increasing block tariff (IBT) as a tool to encourage resource conservation, recover costs, and subsidize low-income consumers. However, it is not clear whether consumers actually respond to marginal prices under IBT. We empirically analyze whether marginal price in an IBT influences residential electricity demand, by combining administrative monthly electricity bill records with a detailed survey of sample households. Results from a bunching analysis and Arellano-Bond estimator show that prices of electricity do not significantly affect monthly electricity consumption. The finding highlights that consumers do not respond to marginal prices under IBT if electricity price is low or if they are unaware of the pricing schedules and have difficulty in understanding how their bills are computed in such tariff structures. This, in turn, has severe implications for the efficacy of the policy objectives of IBT. JEL Classification: C23, D12, L11, L94, Q21 Keywords: Residential electricity demand, shared connections, increasing block tariff, bunching analysis, panel data Billing Knowledge and Consumption Behavior: Experimental Evidence from Nonlinear Electricity Tariffs Increasing block tariff for electricity services is a popular tariff structure in developing countries with the ambition to promote resource conservation among users with high consumption and to provide subsidy for low-income consumers. However, in a complex pricing structure, such as increasing block tariff (IBT), consumers may not know the marginal price they face and might not fully understand how their bill is computed. Thus, in this study, we investigate whether educating consumers about how their monthly electricity bill is calculated in an IBT structure affects electricity consumption. To evaluate the effect of the treatment, we conduct a field experiment with residential electricity consumers in Ethiopia where electricity price is heavily subsidized and shared connections are common. Using monthly consumption data from the electric meters, we find no statistically significant effect after six months in response to the treatment. Our finding suggests that it is not the lack of billing information that makes residential electricity consumers insensitive to the IBT. Alternative reasons, such as the low electricity price are provided. JEL Classification: C93, D12, D83, H42, L94 Keywords: Billing knowledge, consumer behavior, non-linear electricity price, field experiment ISBN: 978-91-88199-27-0 (PRINTED) 978-91-88199-28-7(PDF) Contact information: Tensay Hadush Meles, Department of Economics, School of Business, Economics and Law, University of Gothenburg, P.O. Box 640, SE 405 30, Gothenburg, Sweden. E-mail: tensay.meles@economics.gu.se

Ordens kraft : Politiska eder i Sverige 1520-1718

[2017-09-14] Title: Ordens kraft : Politiska eder i Sverige 1520-1718 Authors: Nauman, Sari Abstract: Political oaths were widespread in medieval times, but all over Europe their use dwindled in the early modern period, resulting in the institution being dismantled in many states. In previous research, this decay has been explained by pointing to the emergence of the state in this period, through processes such as bureaucratization, nationalization, and confessionalization, and, later, secularization. However, as some oaths are still in use in modern state systems, the swearing of them seems to be compatible with modern – bureaucratized, nationalized, and secularized – states. If nothing else, this indicates that the standard model for explaining changes in European oath-taking must be questioned. The main purpose of this dissertation is to analyse why political oaths were used in Sweden in the sixteenth and seventeenth centuries, as well as to explain why the usages changed. It is argued that oaths were performative means of instilling trust in a political relationship. Trust was accomplished by an oral utterance, during which the swearer claimed the position of a trustworthy subject. The study encompasses not only how the force of oaths was created, but also how uncertainty regarding the subject’s trustworthiness was handled, by examining its usage in coronations, rebellions, wars and political meetings. The dissertation has four conclusions. First, not only the use of oaths but also the oath event itself underwent changes during the period studied, leading to changes in its performative force. Second, the shaping of the oath event depended on the degree of uncertainty in the specific political relationship. Third, while in the sixteenth century oaths were used to establish trust in political relationships, in the seventeenth century they were re-directed to establish control. Fourth, the shift from trust to control reflected the rise of a written political culture. When political relationships shifted from being characterized by presence and personal contact, to being characterized by distance and impersonal delegation, written oaths were better suited to the situation. Ultimately, the written form transformed the action, for the ability of a political oath to instil trust was linked to its orality. What a written oath could do, though, was help establish control.

Painting from Within - Developing and Evaluating a Manual-based Art therapy for Patients with Depression

[2017-09-13] Title: Painting from Within - Developing and Evaluating a Manual-based Art therapy for Patients with Depression Authors: Blomdahl, Christina Abstract: Aim: The overall aim was to develop and evaluate a manual-based art-therapy programme for patients with depression, and hence, to clarify treatment effects and to describe participants’ experiences of the treatment. The specific aims were: (I) To explore and describe how art therapy works in relation to therapeutic factors, clinical application, and circumstances in the experimental situation, for patients with depression; (II) To explore what experts in the field of art therapy consider to be the main aspects of treatment for patients with depression in clinical practice; (III) To investigate the effects of manual-based Phenomenological Art Therapy in addition to treatment as usual (PATd/TAU) compared with only treatment as usual (TAU) for patients diagnosed with moderate to severe depression; and (IV) To describe and explore the significance of manual-based Phenomenological Art Therapy as experienced by patients diagnosed with moderate to severe depression. Methods: (I) Systematic literature review according to Realist review; (II) Expert survey according to the Delphi technique (Studies I and II were used as a foundation for developing the manual-based Phenomenological Art Therapy for patients with depression (PATd)); to evaluate the effect and experience of PATd, (III) a randomized controlled trial (RCT) with intention-to-treat design was performed; and, thereafter, an interview study with (IV) a Phenomenological approach, according to Reflective Lifeworld Research. Results: (I) eight therapeutic factors were identified: self-exploration, self-expression, communication, understanding and explanation, integration, symbolic thinking, creativity, and sensory stimulation; (II) resulting in four main aspects of art therapy for patients with depression; expression through art-making and verbal communication concerning, depressive thoughts, feelings, life experiences, and physical symptoms. (III) PATd in addition to Treatment As Usual (TAU) showed a significant reduction of depression and an improved return to work compared to participants receiving only TAU. Self-esteem significantly improved, and suicide ideation did not change for either groups. (IV) PATd facilitates meeting oneself in an inner dialogue between the evident and the unaware. The art-making and describing that experience makes oneself and the situation visible, opening up and altering understanding through the inner dialogue. Conclusions: manual-based PATd seems to work as intended, being an effective treatment, and contributes to recovery for patients with moderate to severe depression.

Airborne particulate matter in a Sub-Saharan Africa city: Nairobi, Kenya, and at an Equatorial high altitude site: Mount Kenya

[2017-09-13] Title: Airborne particulate matter in a Sub-Saharan Africa city: Nairobi, Kenya, and at an Equatorial high altitude site: Mount Kenya Authors: Gaita, Samuel Mwaniki Abstract: In Sub-Saharan Africa (SSA), air quality is gravely understudied despite the existing influential factors such a rapid urbanization and population growth that negatively affect the environment. Majority of urban areas in SSA face challenges that include lack of social services, poor infrastructure development, exponential increase of second-hand vehicles and extensive use of biomass-based fuel for energy needs. There is a systemic lack of continuous monitoring of air pollution in most SSA cities and hence it is yet to be seen if SSA will meet the set air quality targets of the sustainable development goals (SDGs) by the year 2030. Although the focus of air quality is on the urban areas, there is a need to monitor atmospheric composition at remote areas in SSA in order to build a baseline level and understand the influence of anthropogenic and natural aerosol sources on regional/global scale. This thesis work sought to study physical and chemical properties of airborne particulate matter (PM) in a typical SSA urban area, Nairobi city, and a high altitude site, Mount Kenya. Results from spatial distribution of black carbon (BC) and PM2.5 (particulate matter less than 2.5 aerodynamic diameter) showed that air quality on the road to the city and within the city is deteriorating. Factor analysis of the PM2.5 results showed that pollution sources were traffic, mineral dust, industrial, combustion, biomass burning, secondary aerosol and aged sea salt. Traffic and mineral dust contributed about 74% of the PM2.5 in Nairobi. Exposure to particulate pollutants was expressed in terms of deposition fractions from the size segregated PM data. The head airways region was found to receive the highest dose (about 86%) compared to the tracheobronchial and pulmonary regions. The reported high PM2.5 and BC concentrations measured along the main street of Nairobi city, indicated the urban population is frequently exposed to elevated pollutants concentrations and thus have high risk factor to respiratory illnesses and lung cancer. Aerosol study from Mount Kenya showed air pollutants are transported from the surrounding and far away sources by local and regional meteorology dynamics. The results from this study provides insight into the air quality issues from pollution sources, exposure to the population and dispersal to remote regions.

Treåringar, kameror och förskola – en serie diffraktiva rörelser

[2017-09-12] Title: Treåringar, kameror och förskola – en serie diffraktiva rörelser Authors: Magnusson, Lena O Abstract: The aim of this thesis is to examine what happens when three-year-olds are given access to digital cameras, and what shape and form children’s photographic capacity takes within the framework of everyday pre-school activities. The notion that young children in pre-school rarely get to use cameras themselves, and that they take part in photographs produced by pre-school educators as part of an ongoing documenting practice rooted in the curriculum is the point of departure. The study has been conducted through an ethnographic approach further strengthened by post-qualitative thinking, where the research material was produced together with children in two different pre-schools. This material includes the children’s intra-actions with the cameras as well as the photographs that emerge during the course of the study. The thesis moves within a posthumanist theoretical framework, with a special focus on new materialism and agential realism, where humans and non-humans are seen as mutual performative agents. The theoretical perspective permeates the entire study, and does not, therefore, only serve as a support for analyses. Through diffractive readings, the results show that children and cameras approach pre-school and its visual events in a manner that is not recognisable in previous experiences of how pre-school and the life of children have formerly been made visible. In this study, the children use the cameras to create resistances and to look back at the educators, as well as to show what relations come into being with materials, peers, places, spaces and knowledge formation. The children, together with the cameras, also make visible the power of the eye to direct and display, where the cameras also come to be an aesthetic tool with the capacity to both see and make visible in everyday life. This, in turn, also brings to light aspects of ethics and leads to the breaking up of more traditional and normative photographic actions and expressions.

Encuadres espaciales en la representación de las identitades étnico-culturales en La teta asustada, Zona Sur y Nosilatiaj. La Belleza.

[2017-09-08] Title: Encuadres espaciales en la representación de las identitades étnico-culturales en La teta asustada, Zona Sur y Nosilatiaj. La Belleza. Authors: Gómez, Leticia Abstract: This dissertation deals with the cinematographic representations of the interrelations between identity and space in a corpus conformed by three films: The Milk of Sorrow by Claudia Llosa (Peru, 2009); Southern District by Carlos Valdivia (Bolivia, 2009) and Beauty by Daniela Seggiaro (Argentina, 2012). The aim of the present work is to examine how ethnic-cultural identities –indigenous and ‘criolla’– are shaped in relation to the represented spaces: landscapes, houses, gardens and the courtyard. In order to study how ethnic-cultural identities are shaped in interaction with the spaces represented in each of the films and to establish how these spaces are constituted through the characters who inhabit them, we have arranged the analysis in three units, each corresponding to a specific space interrelated to certain ethniccultural identities: the landscapes, the houses and the liminal spaces. Drawing on approaches to cultural identity in recent cultural studies and post- /decolonial studies, as well as theories on space, a methodology is elaborated for the study of the spatial framings of the representation of ethnic-cultural identities. Aspects of gender and class will also be taken into consideration when looking into the shaping of identities in relation to space. The analysis demonstrates that the rural, non-urban, landscapes and the images of “the more-thanhuman world" (Abram) and of nature are associated to the indigenous and to migratory trajectories. Moreover, these spaces are represented as the counterpart of the urban, “whitened criollos”. In all the spaces we have analyzed there are traces of the production of identities generated from the interaction between the indigenous and “lo criollo”, spaces with their own qualities, histories and signs that influence the conformation of identities. Through the interdisciplinary approach employed to analyze how spaces are inextricably linked to the production of identity, this dissertation elaborates a model suitable for applying to a larger corpus of films and even to other artistic expressions.

Improvements in total hip arthroplasty - did they work? Evaluation of different concepts and the consequences of wear

[2017-09-07] Title: Improvements in total hip arthroplasty - did they work? Evaluation of different concepts and the consequences of wear Authors: Johanson, Per-Erik Abstract: Today, total hip arthroplasty (THA) is one of the safest and most efficient surgical treatments. New materials, surgical techniques and design concepts intended to improve THA have not always been successful. Thorough preclinical and early clinical investigations can detect some aspects of under-performing, while continuing surveillance is recommended to detect and analyze reasons for any later appearing flaws. In this thesis, several ways to monitor and assess THA performance are explored and carried out, using survival analysis in registry studies, radiostereometry (RSA), radiology and clinical outcome. In Paper I, a study using the Nordic Arthroplasty Register Association (NARA) registry shows that HRA had an almost 3-fold increased early non-septic revision risk and that risk factors were found to be female sex, certain HRA designs and units having performed few HRA procedures. Papers II and III contain comparisons of highly cross-linked polyethylene (XLPE) and conventional polyethylene (PE). XLPE had a considerably lower wear rate up to 10 years but showed no obvious improvements regarding implant fixation, BMD or clinical outcome. In the NARA registry, in 2 of 4 studied cup designs the XLPE version had a lower risk of revision for aseptic loosening compared to the PE version. Paper IV describes that stem subsidence and retrotorsion measured with RSA at 2 years predicted later aseptic stem failure in an unfavorably altered, previously well-functioning cemented femoral stem. In Paper V and VI, a novel approach to measure articulation wear with RSA in radiodense hip arthroplasty articulations was presented and evaluated. Subsequently, a comparison between ceramic-on-ceramic (COC) and metal-on-conventional PE uncemented THA displayed a considerably lower wear rate, smaller periacetabular bone lesions and a relatively high squeaking rate, the latter with unknown long-term consequences, in the COC hips. Implant fixation, heterotopic ossification and clinical outcome did not differ between articulation types. In conclusion, it was confirmed that implant surveillance can be done with RSA, also in radiodense THA. Early migration predicts later aseptic implant failure. Prolonged surveillance can confirm long-term material and design performance, verify or contradict anticipated advantages as well as detect unanticipated long-term complications.

Grammar and grammaticalization in Manda: An analysis of the wider TAM domain in a Tanzanian Bantu language

[2017-09-07] Title: Grammar and grammaticalization in Manda: An analysis of the wider TAM domain in a Tanzanian Bantu language Authors: Bernander, Rasmus Abstract: This dissertation offers a grammatical description and analysis of Manda (N.11), a Bantu language spoken along Lake Nyasa (Lake Malawi) in southern Tanzania. The study focuses on the “wider” TAM domain, i.e. on how tense, aspect, mood but also modality and negation are expressed in the language, offering a description of the form and function of the various markers employed. In addition, this work sets out to unravel the historical background of these markers and the diachronic processes of change - particularly grammaticalization - through which they have evolved. As Manda is a basically undescribed language, the thesis also includes a brief socio-historical account - focusing on the issues of contact - as well as a grammar sketch describing the fundamentals of the language. This study draws on a combination of methods consisting of both more prototypical field work as well as methods facilitating grammatical reconstruction. The vast bulk of the Manda data have been collected in the field. Hypotheses of change – but also of retention – are based on the synchronic variation found in this data, in comparison to the data of existing older sources as well as from neighboring languages. Furthermore, the Manda data has been compared to Proto-Bantu reconstructions and cross-Bantu as well as cross-linguistic generalizations on functional and formal change. The study shows that Manda in many ways adheres to the general traits of an (Eastern) Bantu language. Fundamentally, the language is highly agglutinative, with e.g. an elaborate noun class system and a rich set of both prefixes and affixes on the verbal word, marking nominal indexation, derivations as well as TAM. With regard to TAM, the study argues that much of the synthetic linguistic material found in Manda can be traced to Proto-Bantu and thus most likely is inherited. In contrast, many innovations and indications of ongoing change are displayed in the periphrastic constructions of the language. These include a set of auxiliary constructions used for expressing aspect, modality but also (non-standard) negation, a borrowed persistive marker and two particles being employed as standard negators.

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