| 1. |
- Aasa, Ulrika
(författare)
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Ambulance Work : Relationships between occupational demands, individual characteristics and health-related outcomes
- 2005
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Although musculoskeletal disorders (MSDs) and other health complaints are an occupational problem for ambulance personnel, there is a lack of knowledge regarding work-related factors associated with MSDs and other health complaints. The overall aim of this thesis was to investigate the relationships between occupational demands, individual characteristics and health-related outcomes among ambulance personnel. A random sample of 234 female and 953 male ambulance personnel participated in a national questionnaire survey on work-related factors, and musculoskeletal and other health complaints. Physical demands was associated with activity limitation due to neck-shoulder and low-back complaints among the female personnel. Among the male personnel, physical demands was associated with low-back complaints and activity limitation due to low-back complaints. Psychological demands was significantly associated with neck-shoulder complaints, sleeping problems, headache and stomach symptoms among both female and male ambulance personnel. Worry about work conditions was associated with musculoskeletal disorders and sleeping problems, headache and stomach symptoms. A local sample of 26 ambulance personnel was followed during a 24-hour work shift and for the next two work-free days. Subjective stress- and energy levels, and cortisol levels were measured at regular intervals, and heart rate was registered continuously by electrocardiogram (ECG). Autonomic reactivity to standardized tests before (pre-work) and at the end of the work shift (post-work) was also investigated. For the whole group, baseline values of heart rate were higher pre-work than post-work, but autonomic reactivity did not differ. Increased reactivity to the mental test, modest deviation in heart rate variability (HRV) pattern during the late night hours at work and higher morning cortisol values during work than during leisure time were observed in personnel with many health complaints, but not among their co-workers without or with few complaints. Ambulance personnel with many health complaints also reported higher psychological demands and tended to be more worried about work conditions. Heart rate (HR), lactate level (LL) and perceived exertion (RPE) were investigated in 17 female and 48 male ambulance personnel during a simulated standardized work task “carry a loaded stretcher”. The ambulance personnel had to carry the loaded stretcher (920 N) up and down three flights of stairs twice. The high physiological strain (HR, LL, RPE) for the male, and near or at maximal strain for the female ambulance personnel, implied the importance to identify what kind of physical capacity is most important for ambulance personnel. Therefore, the explained variance of developed fatigue by tests of cardiorespiratory capacity, muscular strength and endurance, and coordination was investigated. The results showed that VO2max and isometric back endurance were important predictors for development of fatigue when carrying a loaded stretcher. The influence of body size on the relationships between maximal strength and functional performance was investigated in a methodological study. The results confirm that the assessment of physical performance could be confounded by the body weight. Therefore, the models for explaining development of fatigue when carrying the loaded stretcher were adjusted for height and weight. Including height in the models significantly increased the explained variance of accumulated lactate among female, but not among male personnel. Lactate levels were higher among short compared to tall female personnel. Weight had no effect on any of the models. In conclusion, the national survey showed that self-reported physical demands was a risk factor of having MSDs, and that self-reported psychological demands and worry about work were important risk factors of having MSDs and other health complaints. Stress monitoring of ambulance personnel during work and leisure time showed that physiological and subjective stress markers did not show any differences between the 24-hour ambulance work shift and leisure time afterwards. However, ambulance personnel with many health complaints had certain physiological changes during the work shift in comparison with the next two work-free days. The physiological and subjective responses during carrying a loaded stretcher, especially among the female ambulance personnel, showed that female and male ambulance personnel could be exposed to internal exposures at different levels when performing the same work task. A better understanding of the relationships between occupational demands and health-related outcomes require further studies on age- and gender matched groups in long-term perspective studies.
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| 2. |
- Abedan Kondori, Farid, 1983-
(författare)
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Bring Your Body into Action : Body Gesture Detection, Tracking, and Analysis for Natural Interaction
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Due to the large influx of computers in our daily lives, human-computer interaction has become crucially important. For a long time, focusing on what users need has been critical for designing interaction methods. However, new perspective tends to extend this attitude to encompass how human desires, interests, and ambitions can be met and supported. This implies that the way we interact with computers should be revisited. Centralizing human values rather than user needs is of the utmost importance for providing new interaction techniques. These values drive our decisions and actions, and are essential to what makes us human. This motivated us to introduce new interaction methods that will support human values, particularly human well-being.The aim of this thesis is to design new interaction methods that will empower human to have a healthy, intuitive, and pleasurable interaction with tomorrow’s digital world. In order to achieve this aim, this research is concerned with developing theories and techniques for exploring interaction methods beyond keyboard and mouse, utilizing human body. Therefore, this thesis addresses a very fundamental problem, human motion analysis.Technical contributions of this thesis introduce computer vision-based, marker-less systems to estimate and analyze body motion. The main focus of this research work is on head and hand motion analysis due to the fact that they are the most frequently used body parts for interacting with computers. This thesis gives an insight into the technical challenges and provides new perspectives and robust techniques for solving the problem.
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| 3. |
- Abrahamsson, Jan, 1981-
(författare)
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Beyond Going Global : Essays on business development of International New Ventures past early internationalization
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The notion of International New Ventures, or INVs, emerged in academia in the early-to-mid 1990s and generally refers to entrepreneurial firms that tend to internationalize very early in their life-cycle, and whose expansion into foreign markets occurs much more quickly than predicted by earlier theories of the incremental internationalization process. Previous literature proposes effective networking with market partners and, more recently, internationally viable business model among key distinguishing features of INVs that allow for such early and rapid entry into international markets. Nevertheless, little is yet known regarding how these younger firms develop over time and how they could sustain international growth. With the purpose of filling this gap, this doctoral dissertation scrutinizes business models and business model innovation of INVs beyond their early internationalization, with a particular emphasis on INVs’ external relationships configurations. The dissertation consists of four self-contained essays that represent a methodological mixture of qualitative and quantitative approaches and incorporate longitudinal case studies, surveys and register-based data encompassing nine years of Swedish INVs’ development. The findings highlight the importance of the business model as an initial market entry tool, and of business model innovation as a potential growth vehicle over time. Findings also display that INVs work with a broader range of external partners compared to other firms for innovative purposes, and that INVs have different business model innovation patterns compared to other types of internationalized firms. Moreover, INVs focus more heavily on value capture innovations in their business models as they mature and seek to obtain a more centralized position in their industry ecosystem by re-configuring the parameters of existing external relationships or developing new ones. Overall, this dissertation contributes to the international entrepreneurship and business model literature by explicating how maturing INVs need to operate under different business model configurations as compared to emerging INVs, as the original business model might lack scalability after a certain point in time. Furthermore, the dissertation suggests how INVs can pursue a dynamic business model approach and utilize dynamic capabilities to design business models that put the focal firm more in control of the surrounding ecosystem, and reduce constraints that can limit the value capturing potential and thus the growth and development of INVs.
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| 4. |
- Abrahamsson, Pernilla, 1972-
(författare)
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Methodological aspects on microdialysis sampling and measurements
- 2010
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Background: The microdialysis (MD) technique is widely spread and used both experimentally and in clinical practice. The MD technique allows continuous collection of small molecules such as glucose, lactate, pyruvate and glycerol. Samples are often analysed using the CMA 600 analyser, an enzymatic and colorimetric analyser. Data evaluating the performance of the CMA 600 analysis system and associated sample handling are sparse. The aim of this work was to identify sources of variability related to handling of microdialysis samples and sources of error associated with use of the CMA 600 analyser. Further, to develop and compare different application techniques of the microdialysis probes both within an organ and on the surface of an organ. Material and Methods: Papers I and II are mainly in vitro studies with the exception of the No Net Flux calibration method in paper I where a pig model (n=7) was used to examine the true concentration of glucose and urea in subcutaneous tissue. Flow rate, sampling time, vial and caps material and performance of the analyser device (CMA 600) were examined. In papers III and IV normoventilated anaesthetised pigs (n=33) were used. In paper III, heart ischemia was used as intervention to compare microdialysis measurements in the myocardium with corresponding measurements on the heart surface. In paper IV, microdialysis measurements in the liver parenchyma were compared with measurements on the liver surface in association with induced liver ischemia. All animal studies were approved by the Animal Experimental Ethics Committee at Umeå University Sweden. Results: In paper I we succeeded to measure true concentrations of glucose (4.4 mmol/L) and Urea (4.1 mmol/L) in subcutaneous tissue. Paper II showed that for a batch analyse of 24 samples it is preferred to store microdialysis samples in glass vials with crimp caps. For reliable results, samples should be centrifuged before analysis. Paper III showed a new application area for microdialysis sampling from the heart, i.e. surface sampling. The surface probe and myocardial probe (in the myocardium) showed a similar pattern for glucose, lactate and glycerol during baseline, short ischemic and long ischemic interventions. In paper IV, a similar pattern was observed as in paper III, i.e. data obtained from the probe on the liver surface showed no differences compared with data from the probe in liver parenchyma for glucose, lactate and glycerol concentrations during baseline, ischemic and reperfusion interventions. Conclusion: The MD technique is adequate for local metabolic monitoring, but requires methodological considerations before starting a new experimental serie. It is important to consider factors such as flow rate, sampling time and handling of samples in association with the analysis device chosen. The main finding in this thesis is that analyses of glucose, lactate and glycerol in samples from the heart surface and liver surface reflect concentrations sampled from the myocardium and liver parenchyma, respectively.
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| 5. |
- Abramowicz, Konrad, 1983-
(författare)
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Numerical analysis for random processes and fields and related design problems
- 2011
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In this thesis, we study numerical analysis for random processes and fields. We investigate the behavior of the approximation accuracy for specific linear methods based on a finite number of observations. Furthermore, we propose techniques for optimizing performance of the methods for particular classes of random functions. The thesis consists of an introductory survey of the subject and related theory and four papers (A-D).In paper A, we study a Hermite spline approximation of quadratic mean continuous and differentiable random processes with an isolated point singularity. We consider a piecewise polynomial approximation combining two different Hermite interpolation splines for the interval adjacent to the singularity point and for the remaining part. For locally stationary random processes, sequences of sampling designs eliminating asymptotically the effect of the singularity are constructed.In Paper B, we focus on approximation of quadratic mean continuous real-valued random fields by a multivariate piecewise linear interpolator based on a finite number of observations placed on a hyperrectangular grid. We extend the concept of local stationarity to random fields and for the fields from this class, we provide an exact asymptotics for the approximation accuracy. Some asymptotic optimization results are also provided.In Paper C, we investigate numerical approximation of integrals (quadrature) of random functions over the unit hypercube. We study the asymptotics of a stratified Monte Carlo quadrature based on a finite number of randomly chosen observations in strata generated by a hyperrectangular grid. For the locally stationary random fields (introduced in Paper B), we derive exact asymptotic results together with some optimization methods. Moreover, for a certain class of random functions with an isolated singularity, we construct a sequence of designs eliminating the effect of the singularity.In Paper D, we consider a Monte Carlo pricing method for arithmetic Asian options. An estimator is constructed using a piecewise constant approximation of an underlying asset price process. For a wide class of Lévy market models, we provide upper bounds for the discretization error and the variance of the estimator. We construct an algorithm for accurate simulations with controlled discretization and Monte Carlo errors, andobtain the estimates of the option price with a predetermined accuracy at a given confidence level. Additionally, for the Black-Scholes model, we optimize the performance of the estimator by using a suitable variance reduction technique.
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| 6. |
- Abramsson, Marianne
(författare)
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Housing Careers in a Changing Welfare State
- 2003
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The departure point of this thesis was changes to the welfare state. These changes began during the recession in the 1970s and were emphasised in the beginning of the 1990s. The housing market was particularly affected, as the state almost completely withdrew its engagement. Questions were raised as to how the development of the welfare state and the subsequent changes have affected different sectors of the housing market (social housing) and the housing careers of different groups.Besides the introduction the thesis consists of five papers, beginning with a review article on the effect of welfare state changes on the social housing stock in some western countries. The social housing sector (housing the lowest income groups) became more residualised as the concentration of low-income households in this sector increased in most countries. At the same time, government interest in this sector decreased.The second, third and fourth papers follow the housing careers of different groups in three Swedish municipalities during the period 1985–1995. Nest-leaving and choice of tenure of the young population, aged 16–24, in the Gävle municipality were studied. A study of two cohorts showed that nest-leaving was postponed during the recession of the early 1990s when unemployment rates were high among young people. A slight increase in moves to co-operative housing was seen during this period. Immigrants in Jönköping, Gävle and Västerås were studied. Results show that the structure of the local housing market as well as time spent in Sweden are important factors in the housing careers of immigrants. In areas with a large share of owner-occupation, immigrants live in this type of housing to a larger extent. A housing career similar to that of the Swedish population is more common among immigrants who have spent a longer time in Sweden. Residential mobility of seniors towards the city centres in the same municipalities showed only a marginal increase in this type of move. However, the characteristics of those moving were those that, to a large extent, characterise the baby boom generation born in the 1940s. As a result, this type of move can be expected to increase as this group retires.Finally, the fifth paper follows the housing career of four cohorts during the development of the welfare state after 1945. The cohorts were born in 1925, 1942, 1955 and 1970, respectively. They were interviewed about the meaning attached to the terms size, tenure and location, important factors in the development of Swedish housing policy. Despite differences in the housing market at the start of their housing careers, with time the cohorts developed similar demands on size, standard and location. Tenure was not cohort-specific but was instead discussed as degrees of freedom found in owner occupation or rental tenure.
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| 7. |
- Achour, Cyrinne, 1991-
(författare)
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Canonical and non-canonical functions of METTL3 in breast cancer
- 2022
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Gene expression is spatially and temporally regulated at multiple levels. N6-methyladenosine (m6A) is the most prevalent internal modification in messenger RNA (mRNA) and long noncoding RNA (lncRNAs). m6A plays important roles in multiple cellular processes including stem cell pluripotency, adipogenesis, spermatogenesis, neurogenesis, circadian rhythm and development by modulating RNA splicing, export, stability, degradation and translation. Although aberrant m6A methylation has been reported in various types of cancer, the underlying molecular functions of METTL3, the solely catalytic subunit of the m6A-methylase complex, has yet to be defined.m6A has been recently identified in nascent pre-mRNA, and more specifically intronic m6A has been linked to exon skipping events. The occurrence of impaired alternative splicing (AS) is frequently found during the development of cancer. We performed transcriptome wide analysis in breast cancer cell lines and explored AS events. Our results define an AS signature for breast tumorigenesis. We found that METTL3 modulates AS directly through m6A deposition at the intron-exon junctions or indirectly by the m6A deposition in transcripts encoding for splicing factors and transcription factors. In particular, we show that MYC mRNA harbours the m6A mark, suggesting that METTL3 regulates AS indirectly via the regulation of MYC expression. Indeed, the targets of MYC overlapped with METTL3-associated AS events. Importantly, five of the AS events identified and validated in vitro, are linked to a worse prognosis in breast cancer patients. Additionally, we show that METTL3 enhances the breast cancer phenotype through a dual mechanism depending on its sub-cellular localization. We find that the canonical nuclear function of METTL3 decorates transcripts that are involved in cell proliferation and migration. We observe that METTL3 is highly expressed in the cytoplasmic compartment of breast cancer cells from patients. Remarkably, we uncover that the cytoplasmic METTL3 interacts with subunits of the exocyst, whose subunit EXOC7 has been linked to cell adhesion, migration and invasion. Notably, we show that breast cancer cell lines depleted of METTL3 display less gelatinase activity and invadopodia formation, supporting the role of METTL3 in cell invasion via exocytosis.m6A is a reversible modification, which can be demethylated by the erasers FTO and ALKBH5. Depletion of FTO has been shown to increase the level of m6A in mRNA, however recent studies have reported that FTO could demethylate N6,2´-O-dimethyladenosine (m6Am), adjacent to the 7-methylguanosine cap on mRNA. In the cellular model of colorectal cancer CRC1, depletion of FTO leads to a cancer stem cell phenotype and confers chemotherapy resistance. By performing m6A-RNA immunoprecipitation followed by sequencing (MeRIP), we show that knockdown of FTO in CRC1 cells does not affect the global level of m6A in mRNA but of m6Am level.
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| 8. |
- Adamo, Hanibal Hani, 1984-
(författare)
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TINT Tumor Indicating Normal Tissue : new field of diagnostic biomarkers for prostate cancer
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Background: Prostate cancer is the most common cancer in Sweden. Due its highly variable behavior, multifocal nature, and insufficient diagnostic methods, prostate cancer is difficult to diagnose and prognosticate. Some patients have an aggressive lethal disease, but the majority of prostate cancer patients have slow-growing, non-lethal disease with long expected survival without treatment. Current diagnostic methods―serum levels of prostate-specific antigen (PSA) and histological grading of biopsied prostate tissue―often do not give the information required to be able to safely differentiate indolent tumors from potentially lethal ones. Many prostate cancers are difficult to detect by imaging, so tissue biopsy cannot be safely guided towards the tumor, and particularly not towards the most aggressive forms. To overcome this problem, multiple needle biopsies are taken from the organ, but biopsies are small and they sample less than 1% of the whole prostate. In this thesis, we explore the non-malignant prostate tissue adjacent to tumors, which is always sampled in biopsies, and we study adaptive changes in this tissue, which may provide new diagnostic and prognostic markers for prostate cancer. We have therefore proposed that this type of tissue should be termed TINT (Tumor Instructed/indicating Normal Tissue). Methods: In our studies, we used orthotopic rat prostate cancer models with tumors of different aggressiveness. We also used clinical materials from patients diagnosed with prostate cancer at transurethral resection (1975‒1990); the majority of these men were followed with watchful waiting. Analyses were performed with whole-genome expression array, quantitative real-time PCR, immunohistochemistry, and western blotting. Results: Using the animal model, we found that the presence of a tumor induces changes in gene expression in the surrounding tumor-bearing organ (TINT). The gene signature of TINT was linked to processes such as extracellular matrix organization, immune responses, and inflammation. We also showed that some of these adaptive TINT changes appear to be related to the aggressiveness and metastatic potential of the growing tumor, such as increases in macrophages, in mast cells, in vascular densities, and in vascular cell-proliferation. Some of these findings were confirmed by our observations in patient samples. We found that high staining of the extracellular matrix component hyaluronan in the stroma of the non-malignant prostate tissue was prognostic for short cancer-specific survival. We also found that an elevated proportion of C/EBP-beta positive epithelial cells in non-malignant (TINT) prostate tissue was associated with a good prognosis. Conclusions: Using animal experiments and patient samples, we showed that the presence of prostate cancer induces changes in the tumor-bearing organ, alterations associated with tumor aggressiveness, and that grading of these changes in TINT can be used to predict outcome in prostate cancer patients.
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| 9. |
- Addario, Barbara, 1974-
(författare)
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Alpha-actinin - an amazing journey through time and species
- 2011
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In eukaryotes, the actin cytoskeleton plays an important role in a large variety of cellular events. Its reorganization is regulated by a plethora of actin-modulating proteins, such as α-actinin. α-actinin is a ubiquitous actin-binding protein that belongs to the spectrin superfamily. This family, besides α-actinin, includes spectrin, dystrophin and utrophin. Phylogenetic analyses have indicated that the family members arose after several intragene duplications and rearrangements of a common ancestral α-actinin isoform. Up to the invertebrate-vertebrate bifurcation, organisms seemed to have a single, calcium-dependent α‑actinin. After the split, invertebrates have kept this single isoform, in contrast to vertebrates that acquired four distinct isoforms. Of the four vertebrate α-actinin isoforms, the two present in non-muscle cells are typically calcium sensitive while the two muscle isoforms are calcium insensitive. α-actinin in higher organisms is characterized by the presence of three distinct structural domains: a highly conserved N-terminal actin-binding domain, a central rod domain with four spectrin repeats and a calcium-binding C terminus with EF-hand motifs. In some primitive organisms, such as protozoa and fungi, the rod domain of α-actinin contains only one or two spectrin repeats. With the completion of an ever increasing number of genomes, new and atypical α‑actinin sequences had been available that have not been characterized yet. To obtain a firmer understanding of the evolutionary history of α-actinin, the main objective of this study was to identify, purify and biochemically characterize atypical α‑actinin or α‑actinin-like proteins of the parasite Entamoeba histolytica and of the fungus Schizosaccharomyces pombe. Our results show that both isoforms, despite the much shorter rod domain, are able to bind and cross-link actin filaments and therefore can be considered genuine α-actinins.
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| 10. |
- Adenling, Elinor, 1973-
(författare)
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Att bli miljömedveten : Perspektiv på miljöhandbokens textvärld
- 2007
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This dissertation is the study of environmental consciousness as a discursive educational project. The empirical material consist of 18 environmental handbooks that have been published in Sweden during the years 1976-2007 of which 13 appeared between 1988 and 1995. The research work uses the basic assumptions of discourse analysis, namely that language is an important factor in the construction and development of social norms and values. Three areas recieve close attention: questions relating to the form and content of the handbooks, questions relating to the social circumstances in which the handbooks were produced and questions relating to the overall educational significance of the handbooks. In the first instance, the handbooks are examined in the light of three different contextual stories. They can be read as part of wider discussions of environmentally-concsious life-styles, as a development of earlier Swedish discussions about domesticity, health, thrift and consumption, and, finally they can be read as an expression of a narrative about a dominant aspect of modernity – science. The second part of the research work comprises an examination of the handbooks in terms of their audience and educational purpose. What kind of individual is to be shaped by these handbooks? What is anticipated as the desired or ideal environmentalist? Discourse analysis suggests that, collectively, the handbooks project an image of somone who displays qualities of motivation, investigation and judgement. They should be motivated to begin a process of change in their lives, to encourage others to do the same, and to adopt the environmental problems as their own personal problems. The second quality pursued in the handbooks is of someone who should take an active stance towards the environment as a pervasive element in their way of life. They should, therefore, adopt an investigative attitude to the surrounding world, cultivate certain cognitive properties such as watchfulness, thoughtfulness and being suspicious, and constantly ask questions about their surroundings with a view to understanding how actions in their private world has an effect on the wider world. And thirdly, the ideal environmentalist citizen should be someone who demonstrates judgement in balancing polarities and resolving the claims of different standpoints. They should give attention to separating right from wrong, wisdom from madness and, above all, to finding a way of linking their own efforts to what is worth striving for and what is worth avoiding or neglecting. In summary, the subjects identified in the handbooks are expected to avoid extreme positions, to place their own expectations about sustainability on a suitable level, and to be prepared for failure and feelings of guilt. The final part of the investigation – interpreting the wider significance of the handbooks – uses a pluralistic model of analysis which takes its departure from three concepts – ecological modernisation, governmentality and the risk society. Using these orientations, the extent of the discursive educational project of the environmental handbooks is highlighted. If the handbooks are regarded as modernist prescriptions, they are texts which highlights slow and careful change taking place within the present power structure of society. If they are regarded as texts that offer a governmentality prescription, they can be read as texts which promote the transformation of everyday micropractices. And if they are regarded as prescriptions for a risk society, they are texts which enable readers to come to terms with confusion and powerlessness in a complex and risky social context. One main result is that the environmental handbooks display interesting similarities, worthy of futher exploration, supported by a broadened empirical base.
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