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  • Bosson, Jenny A.
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Pulmonary Medicine.
    Mudway, Ian S.
    Sandström, Thomas
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Pulmonary Medicine.
    Traffic-related Air Pollution, Health, and Allergy: The Role of Nitrogen Dioxide2019In: American Journal of Respiratory and Critical Care Medicine, ISSN 1073-449X, E-ISSN 1535-4970, Vol. 200, no 5, p. 523-524Article in journal (Other academic)
  • Durbeej, Natalie
    et al.
    Sörman, Karolina
    Norén Selinus, Eva
    Lundström, Sebastian
    Lichtenstein, Paul
    Hellner, Clara
    Halldner, Linda
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Child and Adolescent Psychiatry. Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden; Child and Adolescent Psychiatry Research center, BUP Klinisk forskningsenhet, Stockholm, Sweden.
    Trends in childhood and adolescent internalizing symptoms: results from Swedish population based twin cohorts2019In: BMC Psychology, E-ISSN 2050-7283, Vol. 7, article id 50Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Previous research has noted trends of increasing internalizing problems (e.g., symptoms of depression and anxiety), particularly amongst adolescent girls. Cross-cohort comparisons using identical assessments of both anxiety and depression in youth are lacking, however.

    METHODS: In this large twin study, we examined trends in internalizing symptoms in samples of 9 year old children and 15 year old adolescents, gathered from successive birth cohorts from 1998 to 2008 (age 9) and 1994-2001 (age 15). Assessments at age 9 were parent-rated, and at age 15 self- and parent-rated. We examined (i) the relation between birth cohorts and internalizing symptoms using linear regressions, and (ii) whether percentages of participants exceeding scale cut-off scores changed over time, using Cochrane Armitage Trend Tests.

    RESULTS: Among 9 year old children, a significantly increasing percentage of participants (both boys and girls) had scores above cut-off on anxiety symptoms, but not on depressive symptoms. At age 15, a significantly increasing percentage of participants (both boys and girls) had scores above cut-off particularly on self-reported internalizing symptoms. On parent-reported internalizing symptoms, only girls demonstrated a corresponding trend.

    CONCLUSION: In line with previous studies, we found small changes over sequential birth cohorts in frequencies of depression and anxiety symptoms in children. Further, these changes were not exclusive to girls.

  • Public defence: 2019-12-11 09:00 N460
    Rebbling, Anders
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Application of fuel design to mitigate ash-related problemsduring combustion of biomass2019Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The energy supply of today is, through the use of fossil energy carriers,contributing to increased net emissions of greenhouse gases. This hasseveral negative effects on our environment and our climate. In order toreduce the impact of this, and possibly to reverse some of the effects, allrenewable energy sources must be used. Biomass is the renewable energycarrier that has the greatest potential to reduce net greenhouse gasemissions, but the transition from fossil fuels to biofuels is challenging.The combustion of biomass is associated with various technical andenvironmental problems such as slagging, corrosion, and emissions ofparticles, soot, or harmful chemical compounds. Most of these problemsare linked to ash chemical reactions involving alkali metals. Therefore, toreduce the risk of operational and environmental problems, it is importantto understand and control the ash transformation reactions involvingalkali metals.The research presented in this thesis has focused on the development oftools, such as models and indices, for predicting the behaviour of variousbiofuels during combustion, and on the development of the concept of fueldesign and implementation of the same during industrial combustion ofbiomass. The development of easy-to-use tools for predicting problematicash behaviour is crucial in order to make it possible to increase the use ofbiomass as an alternative to fossil fuels. The tools presented here are basedon theoretical and empirical knowledge and can be used to predictchallenges concerning the fuel ash composition and to propose relevantfuel design measures.The purpose of fuel design, as used here, is to broaden the fuel feedstockand to increase the usability of biomass in the global energy system. Thisis achieved through measures to change the ash chemical composition inorder to enhance beneficial properties, or reduce problematic properties,via the use of additives or blending of two or more different fuels.The present thesis extends the foundation of knowledge regarding fuel ashtransformation reactions and their implications for operational problemsthrough in-depth laboratory studies and analyses. Furthermore, thefeasibility of applying this extended knowledge in the medium and largescaleindustrial combustion of biomass is demonstrated and validated. More specifically, a slagging index has been developed using the results ofseveral years of combustion experiments. Fuel designs based on the indexwas demonstrated during normal operation in local and district heatingplants. Furthermore, a model was developed for predicting slaggingproblems that take into account both the chemical composition of the fueland the burner technology.Several studies have also been performed on different fuel designs basedon the same foundation as the index and the model. Additives to supply forexample calcium and sulphur, as well as the clay kaolin, have been used toreduce both technical and environmental problems.The conclusion is that fuel design, based on ash chemistry, is a possiblepath for increased fuel flexibility and a broader feedstock for bioenergy.

  • Savas, Süleyman
    et al.
    School of Information Technology, Halmstad University, Halmstad, Sweden; Department of Computers Science, Lund University, Lund, Sweden.
    Ul-Abdin, Zain
    School of Information Technology, Halmstad University, Halmstad, Sweden.
    Nordström, Tomas
    Umeå University.
    A framework to generate domain-specific manycore architectures from dataflow programs2020In: Microprocessors and microsystems, ISSN 0141-9331, E-ISSN 1872-9436, Vol. 72Article in journal (Refereed)
    Abstract [en]

    In the last 15 years we have seen, as a response to power and thermal limits for current chip technologies, an explosion in the use of multiple and even many computer cores on a single chip. But now, to further improve performance and energy efficiency, when there are potentially hundreds of computing cores on a chip, we see a need for a specialization of individual cores and the development of heterogeneous manycore computer architectures.

    However, developing such heterogeneous architectures is a significant challenge. Therefore, we propose a design method to generate domain specific manycore architectures based on RISC-V instruction set architecture and automate the main steps of this method with software tools. The design method allows generation of manycore architectures with different configurations including core augmentation through instruction extensions and custom accelerators. The method starts from developing applications in a high-level dataflow language and ends by generating synthesizable Verilog code and cycle accurate emulator for the generated architecture.

    We evaluate the design method and the software tools by generating several architectures specialized for two different applications and measure their performance and hardware resource usages. Our results show that the design method can be used to generate specialized manycore architectures targeting applications from different domains. The specialized architectures show at least 3 to 4 times better performance than the general purpose counterparts. In certain cases, replacing general purpose components with specialized components saves hardware resources. Automating the method increases the speed of architecture development and facilitates the design space exploration of manycore architectures.

  • Westergren, Ulrika H.
    et al.
    Umeå University, Faculty of Social Sciences, Department of Informatics.
    Holmström, Jonny
    Umeå University, Faculty of Social Sciences, Department of Informatics.
    Mathiassen, Lars
    Georgia State University, Center for Process Innovation, J. Mack Robinson College of Business, .
    Partnering to create IT-based value: A Contextual Ambidexterity Approach2019In: Information and organization, ISSN 1471-7727, E-ISSN 1873-7919, Vol. 29, no 4, article id 100273Article in journal (Refereed)
    Abstract [en]

    Going beyond the boundary of the firm and traditional notions of how IT contributes to value creation, scholars have started to investigate under what conditions, in what ways, and with which results firms can co-create IT-based value. However, we lack comprehensive insights into how firms can develop such collaborative partnerships and the types of value they create at different stages of the process.Using a qualitative case study, we analyze in detail how a mining company, a manufacturer of mining machinery, and an IT provider developed a joint venture over a ten-year period. Drawing on ambidexterity theory, we show how the three firms successfully built a context that encouraged alignment of interests and allowed the participants to adapt to emerging conditions as they collaborated to create IT-based value. Moreover, we uncover the different types of value they created over the various stages of developing the collaboration. As a result, we contribute to the literature on IT-based value co-creation with insights into how inter-firm collaboration can be developed to create different types of IT-based value. In addition, we advance contextual ambidexterity theory by demonstrating how it applies to developing new partnerships between firms. 

  • Robroek, Suzan JW
    et al.
    Nieboer, Daan
    Järvholm, Bengt
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine.
    Burdorf, Alex
    Educational differences in duration of working life and loss of paid employment: working life expectancy in The Netherlands2019In: Scandinavian Journal of Work, Environment and Health, ISSN 0355-3140, E-ISSN 1795-990X, article id 3843Article in journal (Refereed)
    Abstract [en]

    Objectives: This study aims to provide insight into educational differences in duration of working life by working life expectancy (WLE) and working years lost (WYL) through disability benefits and other non-employment states in the Netherlands.

    Methods: Monthly information on employment status of the Dutch population (N=4 999 947) between 16 and 66 years from 2001‒2015 was used to estimate working life courses and loss of working years for specific non-employment states. Across educational groups, bi-directional transitions between paid employment and non-employment states were calculated. Using a multistate model, the WLE and WYL at age 16, 30, 50 and up to 66 years as statutory retirement age were estimated for each educational group, stratified by gender.

    Results: Low-educated men and women had a 7.3 (men) and 9.9 (women) years lower WLE at age 30 than high-educated men and women. Among low-educated men, 3.4 working years were lost due to disability benefit compared to 0.8 among high-educated men. Low-educated women lost 3.0 working years due to disability benefit compared to 1.4 among high-educated women.

    Conclusions: There are large educational inequalities over the course of working life. Among low-educated workers, more working years are lost due to unemployment, no income, and especially disability benefits. The latter reflects large educational inequalities in health and working conditions. The metrics of WLE and WYL provide useful insights into the life-course perspective on working careers.

  • Persson, Kristina
    Naturanimering i sakprosatexter för barn om naturens cykliska processer2019In: Svenskans beskrivning 36: Förhandlingar vid trettiosjätte sammankomsten, Uppsala 25-27 oktober 2017 / [ed] Marco Bianchi, David Håkansson, Björn Melander, Linda Pfister, Maria Westman, Carin Östman, Uppsala: Uppsala universitet , 2019, p. 219-229Conference paper (Refereed)
  • Petrusenko, Nadezda
    Umeå University, Faculty of Social Sciences, Unit of Economic History. Umeå University.
    Grön marknadsföring eller greenwashing?: en diskursiv konstruktion av sopsugssystemet som en miljövänlig produkt på slutet av 1980-talet och början på 1990-talet2019In: 1959 års ekonomiska historia: en festskrift i samband med professor Lena Andersson-Skogs 60-årsdag 2019 / [ed] Helén Strömberg, Umeå: Umeå Universitet , 2019, p. 51-55Chapter in book (Other academic)
  • Saidi, Olfa
    et al.
    Zoghlami, Nada
    Bennett, Kathleen E
    Mosquera, Paola
    Umeå University, Faculty of Medicine, Department of Epidemiology and Global Health.
    Malouche, Dhafer
    Capewell, Simon
    Romdhane, Habiba Ben
    O'Flaherty, Martin
    Explaining income-related inequalities in cardiovascular risk factors in Tunisian adults during the last decade: comparison of sensitivity analysis of logistic regression and Wagstaff decomposition analysis2019In: International Journal for Equity in Health, ISSN 1475-9276, E-ISSN 1475-9276, Vol. 18, article id 177Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: It is important to quantify inequality, explain the contribution of underlying social determinants and to provide evidence to guide health policy. The aim of the study is to explain the income-related inequalities in cardiovascular risk factors in the last decade among Tunisian adults aged between 35 and 70 years old.

    METHODS: We performed the analysis by applying two approaches and compared the results provided by the two methods. The methods were global sensitivity analysis (GSA) using logistic regression models and the Wagstaff decomposition analysis.

    RESULTS: Results provided by the two methods found a higher risk of cardiovascular diseases and diabetes in those with high socio-economic status in 2005. Similar results were observed in 2016. In 2016, the GSA showed that education level occupied the first place on the explanatory list of factors explaining 36.1% of the adult social inequality in high cardiovascular risk, followed by the area of residence (26.2%) and income (15.1%). Based on the Wagstaff decomposition analysis, the area of residence occupied the first place and explained 40.3% followed by income and education level explaining 19.2 and 14.0% respectively. Thus, both methods found similar factors explaining inequalities (income, educational level and regional conditions) but with different rankings of importance.

    CONCLUSIONS: The present study showed substantial income-related inequalities in cardiovascular risk factors and diabetes in Tunisia and provided explanations for this. Results based on two different methods similarly showed that structural disparities on income, educational level and regional conditions should be addressed in order to reduce inequalities.

  • Lico, Angjelo
    et al.
    Umeå University, Faculty of Social Sciences, Department of Informatics.
    Andersson, Johannes
    Umeå University, Faculty of Social Sciences, Department of Informatics.
    Augmented reality inom sjukvården: En studie om utmaningar och möjligheter för AR i sjukvården2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This essay is about the use of Augmented Reality in healthcare, to highlight the challenges and the opportunities that generate from the subject. With the continual development of technology that is introduced to healthcare, it is important to understand the effects that Augmented Reality has on the workers that use it, and the people who are affected by it. This essay is based on a literature review to be able to examine the information that is best suited to contribute to the work. We created a table to present our findings by identifying two perspectives that are affected by the use of AR. The two perspectives are introduced as Care providers and Care recipients, which are the two main signifiers in hospitals and the healthcare environment. The conclusion of this essay will reveal the opportunities and the challenges of Augmented Reality in healthcare and may serve as a suggestion to what the future of Augmented Reality in healthcare can hold.

  • Westerlund, Anna
    et al.
    Umeå University, Faculty of Medicine, Department of Epidemiology and Global Health.
    Nilsen, Per
    Linköpings universitet, Department of Medical and Health Sciences, Division of Community Medicine.
    Sundberg, Linda
    Umeå University, Faculty of Medicine, Department of Epidemiology and Global Health.
    Implementation of Implementation Science Knowledge: The Research-Practice Gap Paradox2019In: Worldviews on Evidence-Based Nursing, ISSN 1545-102X, E-ISSN 1741-6787, Vol. 16, no 5, p. 332-334Article in journal (Refereed)
  • Karlsson, Sofia
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Surgery.
    Saveman, Britt-Inger
    Umeå University, Faculty of Medicine, Department of Nursing.
    Gyllencreutz, Lina
    Umeå University, Faculty of Medicine, Department of Nursing.
    The medical perspective on mining incidents: Interviews with emergency medical service (EMS) personnel2019In: International Journal of Emergency Services, ISSN 2047-0894, E-ISSN 2047-0908, Vol. 8, no 3, p. 236-246Article in journal (Refereed)
    Abstract [en]

    Purpose: The purpose of this paper is to examine emergency medical service (EMS) personnel’s perceptions and experiences of managing underground mining injury incidents.

    Design/methodology/approach: In total, 13 EMS personnel were interviewed according to a semi-structured interview guide. The interviews were transcribed verbatim and analyzed using qualitative content analysis.

    Findings: An underground mining environment was described as unfamiliar and unsafe and, with no guidelines for operational actions in an extreme environment, such as underground mines, the EMS personnel were uncertain of their role. They therefore became passive and relied on the rescue service and mining company during a major incident. However, the medical care was not considered to be different from any other prehospital care, although a mining environment would make the situation more difficult and it would take longer for the mine workers to be placed under definitive care.

    Originality/value: This study complements earlier studies by examining the EMS personnel’s perceptions and experiences of major incidents.

  • Sjödin, Tord
    Umeå University, Faculty of Science and Technology, Department of Mathematics and Mathematical Statistics.
    On Mixtures of Gamma Distributions, Distributions with Hyperbolically Monotone Densities and Generalized Gamma Convolutions (GGC)2019In: Probability and Mathematical Statistics, ISSN 0208-4147Article in journal (Refereed)
    Abstract [en]

    Let Y be a standard Gamma(k) distributed random variable (rv), k > 0, and let X be an independent positive rv. If X has a hyperbolically monotone density of order k (HMk), then Y ·X and Y/X are generalized gamma convolutions (GGC). This extends work by Roynette et al. and Behme and Bondesson. The same conclusion holds with Y replaced by a finite sum of independent gamma variables with sum of shape parameters at most k. Both results are applied to subclasses of GGC.

  • Arumugam, Ashokan
    et al.
    Markström, Jonas
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Section of Physiotherapy.
    Häger, Charlotte
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Section of Physiotherapy.
    A novel test reliably captures hip and knee kinematics and kinetics during unanticipated/anticipated diagonal hops in individuals with anterior cruciate ligament reconstruction2019In: Journal of Biomechanics, ISSN 0021-9290, E-ISSN 1873-2380Article in journal (Refereed)
    Abstract [en]

    Unanticipated land-and-cut maneuvers might emulate lower limb mechanics associated with anterior cruciate ligament (ACL) injury. Reliability studies on landing mechanics of such maneuvers are however lacking. This study investigated feasibility and within-session reliability of landing mechanics of a novel one-leg double-hop test, mimicking a land-and-cut maneuver, in individuals with ACL reconstruction (ACLR). Our test comprised a forward hop followed by a diagonal hop in either of two directions (medial/lateral) under anticipated and unanticipated conditions. Twenty individuals with a unilateral ACLR (aged 24.2 ± 4.2 years, 0.7-10.8 years post-surgery) performed three successful hops/direction per leg. We determined reliability (intraclass correlation coefficient [ICC]) and agreement (standard error of measurement [SEM]) of 3-dimensional hip and knee angles and moments during the deceleration phase of the land-and-cut maneuver (vulnerable for non-contact ACL injuries). Mean success rate for unanticipated hops was 71-77% and for anticipated hops 91-95%. Both limbs demonstrated moderate-excellent reliability (ICC 95% confidence intervals: 0.50-0.99) for almost all hip and knee peak angles and moments in all planes and conditions, with a few exceptions: poor-good reliability for hip and knee frontal and/or transverse plane variables, especially for lateral diagonal hops. The SEMs were ≤5° and ≤0.23 N·m/kg·m for most peak angles and moments, respectively. Our test seems feasible and showed satisfactory reliability for most hip and knee angles and moments; however, low knee abduction and internal rotation angles and moments, and moderate reliability of these moments deserve consideration. The test appears to challenge dynamic knee control and may prove valuable in evaluation during knee rehabilitation.

  • Eriksson, Helena P.
    et al.
    Occupational and Environmental Medicine, Sahlgrenska University Hospital, Gothenburg, Sweden; Occupational and Environmental Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
    Forsell, Karl
    Occupational and Environmental Medicine, Norrland University Hospital, Umeå, Sweden; Occupational and Environmental Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
    Andersson, Eva
    Occupational and Environmental Medicine, Sahlgrenska University Hospital, Gothenburg, Sweden; Occupational and Environmental Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
    Mortality from cardiovascular disease in a cohort of Swedish seafarers2019In: International Archives of Occupational and Environmental Health, ISSN 0340-0131, E-ISSN 1432-1246Article in journal (Refereed)
    Abstract [en]

    PURPOSE: The aim of this study was to investigate whether Swedish seafarers have increased mortality from cardiovascular disease compared with the general population.

    METHODS: Register-based longitudinal cohort study of 85,169 Swedish seafarers where all subjects with a minimum of 30 days service registered in the Seafarers' Register 1985-2013 were included. Mortality from coronary heart disease, cerebrovascular disease and total mortality for comparison were analysed by calculating standardised mortality ratios (SMRs), with 95% confidence intervals (CIs). Mortality was further analysed by gender, duty on board, type of vessel, and over time.

    RESULTS: There was no increase in either mortality from cardiovascular disease or total mortality for seafarers, who had worked solely on passenger ferries. Mortality from coronary heart disease and cerebrovascular disease was increased for male seafarers < 46 years old who had worked on different types of vessels, SMR 1.48 (95% CI 1.06-2.01) and SMR 1.93 (95% CI 1.16-3.02), respectively. Analysing the seafarers by duty showed significantly increased SMRs from coronary heart disease in males aged < 46 of the categories "deck crew" and "engine officer/crew (ever)". The total mortality for seafarers who had worked on different types of vessels was increased; males SMR 1.05 (95% CI 1.02-1.09) and females SMR 1.17 (95% CI 1.04-1.30), but decreased over time.

    CONCLUSIONS: No increased mortality on passenger ferries but younger male seafarers on different types of vessels had increased mortality from cardiovascular disease. Reduction of hazardous occupational exposures onboard is important, such as shift work, stress and noise.

  • De Vries, Bouke
    Umeå University, Faculty of Arts, Department of historical, philosophical and religious studies.
    ‘I am your son, mother’: Severe dementia and duties to visit parents who can’t recognise you2019In: Medicine, Health care and Philosophy, ISSN 1386-7423, E-ISSN 1572-8633Article in journal (Refereed)
    Abstract [en]

    It is commonly assumed that many, if not most, adult children have moral duties to visit their parents when they can do so at reasonable cost. However, whether such duties persist when the parents lose the ability to recognise their children, usually due to dementia, is more controversial. Over 40% of respondents in a public survey from the British Alzheimer’s Society said that it was “pointless” to keep up contact at this stage. Insofar as one cannot be morally required to do pointless things, this would suggest that children are relieved of any duties to visit their parents. In what appears to be the only scholarly treatment of this issue, Claudia Mills has defended this view, arguing that our duties to visit our parents require a type of relationship that is lost when parents no longer remember who their children are. This article challenges Mills’ argument. Not only can children be duty-bound to visit parents who have lost the ability to recognise them, I argue that many children do in fact have such duties. As I show, these duties are grounded in any special interests that their parents have in their company; the fact that visiting their parents might allow them to comply with generic duties of sociability; and/or the fact that such visits allow them to express any gratitude that they owe their parents.

  • Pastula, Agnieszka
    et al.
    Marcinkiewicz, Janusz
    Cellular Interactions in the Intestinal Stem Cell Niche2019In: Archivum Immunologiae et Therapiae Experimentalis, ISSN 0004-069X, E-ISSN 1661-4917, Vol. 67, no 1, p. 19-26Article, review/survey (Refereed)
    Abstract [en]

    Epithelial cells are one of the most actively cycling cells in a mammalian organism and therefore are prone to malignant transformation. Already during organogenesis, the connective tissue (mesenchyme) provides instructive signals for the epithelium. In an adult organism, the mesenchyme is believed to provide crucial regulatory signals for the maintenance and regeneration of epithelial cells. Here, we discuss the role of intestinal myofibroblasts, α-smooth muscle actin-positive stromal (mesenchymal) cells, as an important regulatory part of the intestinal stem cell niche. Better understanding of the cross-talk between myofibroblasts and the epithelium in the intestine has implications for advances in regenerative medicine, and improved therapeutic strategies for inflammatory bowel disease, intestinal fibrosis and colorectal cancer.

  • Pastula, Agnieszka
    et al.
    Middelhoff, Moritz
    Brandtner, Anna
    Tobiasch, Moritz
    Höhl, Bettina
    Nuber, Anders H.
    Demir, Ihsan Ekin
    Neupert, Steffi
    Kollmann, Patrick
    Mazzuoli-Weber, Gemma
    Quante, Michael
    Three-Dimensional Gastrointestinal Organoid Culture in Combination with Nerves or Fibroblasts: A Method to Characterize the Gastrointestinal Stem Cell Niche2016In: Stem Cells International, ISSN 1687-9678, article id 3710836Article in journal (Refereed)
    Abstract [en]

    The gastrointestinal epithelium is characterized by a high turnover of cells and intestinal stem cells predominantly reside at the bottom of crypts and their progeny serve to maintain normal intestinal homeostasis. Accumulating evidence demonstrates the pivotal role of a niche surrounding intestinal stem cells in crypts, which consists of cellular and soluble components and creates an environment constantly influencing the fate of stem cells. Here we describe different 3D culture systems to culture gastrointestinal epithelium that should enable us to study the stem cell niche in vitro in the future: organoid culture and multilayered systems such as organotypic cell culture and culture of intestinal tissue fragments ex vivo. These methods mimic the in vivo situation in vitro by creating 3D culture conditions that reflect the physiological situation of intestinal crypts. Modifications of the composition of the culture media as well as coculturing epithelial organoids with previously described cellular components such as myofibroblasts, collagen, and neurons show the impact of the methods applied to investigate niche interactions in vitro. We further present a novel method to isolate labeled nerves from the enteric nervous system using Dclk1-CreGFP mice.

  • Grip, Helena
    et al.
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics. Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Section of Physiotherapy.
    Tengman, Eva
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Section of Physiotherapy.
    Liebermann, Dario G
    Häger, Charlotte
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Section of Physiotherapy.
    Kinematic analyses including finite helical axes of drop jump landings demonstrate decreased knee control long after anterior cruciate ligament injury2019In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 14, no 10, article id e0224261Article in journal (Refereed)
    Abstract [en]

    The purpose was to evaluate the dynamic knee control during a drop jump test following injury of the anterior cruciate ligament injury (ACL) using finite helical axes. Persons injured 17-28 years ago, treated with either physiotherapy (ACLPT, n = 23) or reconstruction and physiotherapy (ACLR, n = 28) and asymptomatic controls (CTRL, n = 22) performed a drop jump test, while kinematics were registered by motion capture. We analysed the Preparation phase (from maximal knee extension during flight until 50 ms post-touchdown) followed by an Action phase (until maximal knee flexion post-touchdown). Range of knee motion (RoM), and the length of each phase (Duration) were computed. The finite knee helical axis was analysed for momentary intervals of ~15° of knee motion by its intersection (ΔAP position) and inclination (ΔAP Inclination) with the knee's Anterior-Posterior (AP) axis. Static knee laxity (KT100) and self-reported knee function (Lysholm score) were also assessed. The results showed that both phases were shorter for the ACL groups compared to controls (CTRL-ACLR: Duration 35±8 ms, p = 0.000, CTRL-ACLPT: 33±9 ms, p = 0.000) and involved less knee flexion (CTRL-ACLR: RoM 6.6±1.9°, p = 0.002, CTRL-ACLR: 7.5 ±2.0°, p = 0.001). Low RoM and Duration correlated significantly with worse knee function according to Lysholm and higher knee laxity according to KT-1000. Three finite helical axes were analysed. The ΔAP position for the first axis was most anterior in ACLPT compared to ACLR (ΔAP position -1, ACLPT-ACLR: 13±3 mm, p = 0.004), with correlations to KT-1000 (rho 0.316, p = 0.008), while the ΔAP inclination for the third axis was smaller in the ACLPT group compared to controls (ΔAP inclination -3 ACLPT-CTRL: -13±5°, p = 0.004) and showed a significant side difference in ACL injured groups during Action (Injured-Non-injured: 8±2.7°, p = 0.006). Small ΔAP inclination -3 correlated with low Lysholm (rho 0.391, p = 0.002) and high KT-1000 (rho -0.450, p = 0.001). Conclusions Compensatory movement strategies seem to be used to protect the injured knee during landing. A decreased ΔAP inclination in injured knees during Action suggests that the dynamic knee control may remain compromised even long after injury.

  • Martinez Gunnarsson, Sara
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Främmande växtarter: En studie av vägkanter2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    In Sweden, there are about 2,000 alien species of which 388 are invasive alien species. Invasive alien species are species that compete and create problems for the native species we have in our nature. One of the major drivers of the introduction of alien species is transport. Transport between different geographical areas increases from year to year, making it easier for new alien species to enter the country. The purpose of this work is to investigate the distribution of alien species along roads of different sizes with different amount of traffic, to be able to get an overview of how the number of cars passing a road affects the spread of alien species and whether it differs among roads. Roads of different sizes were inventoried, in the municipalities of Lekeberg and Laxå, Sweden. Two of the roads were highways, 3 middle sized roads and 3 small sized roads. All species in the sample sites were inventoried, including native species. One-way Anova was used to check if there were any significant differences. The result shows that where most alien species were found, least native species could also be found. Other studies have found linkages between paved roads and invasive species, where it was found that paved roads had more alien species than gravel roads. The result of this study showed that most foreign species could be found along the middle roads and least along the small roads. This could be due to the smaller roads having less traffic intensity, which means that there is less chance of alien species entering these roads by cars. The fact that most species were found on the intermediately sized roads compared to the highways may be due to the higher speed and a higher traffic flow. 

  • Jäder, Jonas
    et al.
    Umeå University, Faculty of Science and Technology, Umeå Mathematics Education Research Centre (UMERC). School of Education, Health and Social Studies, Dalarna University, Falun, Sweden.
    Lithner, Johan
    Umeå University, Faculty of Science and Technology, Umeå Mathematics Education Research Centre (UMERC).
    Sidenvall, Johan
    Umeå University, Faculty of Science and Technology, Umeå Mathematics Education Research Centre (UMERC).
    Mathematical problem solving in textbooks from twelve countries2019In: International Journal of Mathematical Education in Science and Technology, ISSN 0020-739X, E-ISSN 1464-5211Article in journal (Refereed)
    Abstract [en]

    A selection of secondary school mathematics textbooks from twelve countries on five continents was analysed to better understand the support they might be in teaching and learning mathematical problem solving. Over 5700 tasks were compared to the information provided earlier in each textbook to determine whether each task could be solved by mimicking available templates or whether a solution had to be constructed without guidance from the textbook. There were similarities between the twelve textbooks in the sense that most tasks could be solved using a template as guidance. A significantly lower proportion of the tasks required a solution to be constructed. This was especially striking in the initial sets of tasks. Textbook descriptions indicating problem solving did not guarantee that a task solution had to be constructed without the support of an available template.

  • Naumburg, Estelle
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Paediatrics. Pediatrics department, Östersund Hospital, Östersund, Sweden.
    Söderström, Lars
    Increased risk of pulmonary hypertension following premature birth2019In: BMC Pediatrics, ISSN 1471-2431, E-ISSN 1471-2431, Vol. 19, no 1, article id 288Article in journal (Refereed)
    Abstract [en]

    Background: Pulmonary hypertension (PAH) among children and adults has been linked to premature birth, even after adjustments for known risk factors such as congenital heart disease and chronic lung disease. The aim of this population-based registry study was to assess the risk of PAH following exposure to premature birth and other factors in the decades when modern neonatal care was introduced and survival rates increased.

    Methods: Data on pulmonary hypertension and perinatal factors were retrieved from population-based governmental and national quality registers. Cases were adults and children over five years of age with pulmonary hypertension born from 1973 to 2010 and individually matched to six controls by birth year and delivery hospital. Conditional multiple logistic regression was performed to assess the risk of pulmonary hypertension following premature birth and to adjust for known confounding factors for the total study population and for time of birth, grouped into five-year intervals.

    Results: In total, 128 cases and 768 controls were included in the study group. Preterm birth was over three times more common among cases (21%) than among controls (6%). The overall adjusted risk of pulmonary hypertension was associated with premature birth, OR = 4.48 (95% CI; 2.10–9.53). Maternal hypertension, several neonatal risk factors and female gender were independently associated with PAH when potential confounders were taken into account. For each five-year period, the risk of PAH following premature birth increased several times for children born in the 2000s and later, OR = 17.08 (95% CI 5.60–52.14).

    Conclusions: Preterm birth, along with other factors, significantly contributes to PAH. PAH following premature birth has increased over the last few decades. Our study indicates that new, yet unknown factors may play a role in the risk of preterm-born infants developing PAH later in life.

  • Public defence: 2019-12-06 13:00 Hörsal B, Unod T9, Umeå
    Holmgren, Klas
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Surgery.
    Permanent stoma after anterior resection for rectal cancer: prevalence and mechanisms2019Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    While sphincter-saving surgery constitutes standard treatment for rectal cancer, anterior resection still harbours a significant risk of a permanent stoma in the long run. Although anastomotic leakage plays a major role in this surgical dilemma, the exact mechanisms are not known, while surveys indicate a stoma-free outcome is essential for a majority of patients. To address this issue, the overall aim of the present thesis was to investigate the permanent stoma prevalence in patients undergoing anterior resection for rectal cancer in Sweden, and to identify plausible mechanisms that impede prospects of a stoma-free outcome.

    In a population-based cohort, chart review of patients who had anterior resection for rectal cancer in the Northern healthcare region in Sweden between 2007 and 2013 showed that 75 out of 316 (24%) patients ended up with a permanent stoma. Of 274 patients (87%) primarily defunctioned with a stoma, 229 underwent stoma closure, 21 (9%) of whom suffered major complications that required return to theatre or worse. A permanent stoma was shown to be more common among patients with anastomotic leakage and an advanced tumour stage.

    A registry-based method to estimate nationwide stoma outcome after anterior resection for rectal cancer was developed, using data from the Swedish Colorectal Cancer Registry and the National Patient Registry. With a chart-reviewed cohort as reference, stoma outcome was assessed with a positive predictive value of 85.1%, and a negative predictive value of 100.0%. In patients operated in Sweden between 2007 and 2013, the registry-based method determined that 942 out of 4768 (19.8%) had a permanent stoma, while stoma rates varied substantially between different healthcare regions.

    In a 1:1 matched case-control study of 82 patients who had curative resection for non-disseminated colorectal cancer, a subgroup analysis of 34 patients with rectal cancer displayed biomarker aberrations in serum measured preoperatively in those with anastomotic leakage. Compared to complication-free controls, 15 proteins related to inflammation were elevated, of which two (C-X-C motif chemokine 6, and C-C motif chemokine 11) remained significant after adjustment for multiple testing.

    Based on a cohort of 4529 patients who had anterior resection, tumour height served as a proxy to determine the extent of mesorectal excision, while long-term stoma outcome was classified using a previously validated registry-based method. Defunctioning stomas significantly decreased chances of a stoma-free outcome, especially in patients undergoing partial mesorectal excision; for these patients, faecal diversion was also least beneficial in terms of reducing anastomotic leakage.

    In conclusion, every fifth patient undergoing anterior resection for rectal cancer in Sweden eventually ends up with a permanent stoma. Although construction of a defunctioning stoma decreases the risk of symptomatic anastomotic leakage, subsequent takedown surgery carries a substantial risk of major complications, while chances of a long-term stoma-free outcome become significantly reduced. To facilitate selective use of faecal diversion, novel markers to identify high-risk anastomoses prior to surgery have been identified, but require validation in larger prospective settings. Anterior resection without a defunctioning stoma should be considered in appropriately informed patients for whom a stoma-free outcome is of importance. In particular, this holds true for patients eligible for partial mesorectal excision, where anastomotic dehiscence is less frequent and the advantageous effects of a defunctioning stoma are limited.

  • Public defence: 2019-12-06 09:00 933, Unod B 9, Umeå
    Farag, Salah I.
    Umeå University, Faculty of Medicine, Department of Molecular Biology (Faculty of Medicine). Umeå University.
    Biogenesis, function and regulation of the type III secretion translocon of Yersinia pseudotuberculosis2019Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Many Gram negative bacteria use type III secretion systems to cross-talk with eukaryotic cells. Type III secretion system assembly and function is tightly regulated. It initiates with assembly of a basal body-like structure, and is followed by a cytoplasmic-located substrate sorting and export platform that first engages with early substrates required for needle assembly. At the needle tip, a translocon is formed upon eukaryotic cell contact to allow the translocation of effector proteins to the host cell. The focus of this thesis is on understanding aspects of biogenesis, regulation and function of the translocon and its interaction with the host cell. Research questions are addressed in enteropathogenic Yersinia pseudotuberculosis model.

    Prioritising the secretion of translocon components before effector proteins is a task given partly to the InvE/MxiC/HrpJ family of proteins. In Yersinia, homology to this protein family is partitioned over two proteins; YopN and TyeA. Certain Yersinia strains naturally produce a single YopN/TyeA polypeptide hybrid. To understand the implications of hybrid formation towards type III secretion control, a series of mutants were engineered to produce only a single hybrid peptide. Using in vitro assays revealed no difference in substrate secretion profiles between parent and mutants. Moreover, no obvious prioritisation of secretion between translocator and effector substrates was observed. Although these in vitro studies indicate that the YopN-TyeA single polypeptide is fully functionally competent, these mutants were attenuated in the mouse infection model. Hence, natural production of YopN and TyeA as a single polypeptide alone is unlikely to confer a fitness advantage to the infecting bacteria and is unlikely to orchestrate hierarchal substrate secretion.

    The YopB and YopD translocon components form a pore in the host cell plasma membrane to deliver the effectors into the host cell. To better understand how YopD contributes to the biogenesis, function and regulation of the translocon pore, a series of mutants were constructed to disrupt two predicted α-helix motifs, one lying at the N-terminus and the other at the C-terminus. Based upon phenotypes associated with environmental control of Yop synthesis and secretion, effector translocation, evasion of phagocytosis, killing of immune cells and virulence in a mouse infection model, the mutants were grouped into three phenotypic classes. A particularly interesting mutant class maintained full T3SS function in vitro, but were attenuated for virulence in a murine oral-infection model. To better understand the molecular basis for these phenotypic differences, the effectiveness of RAW 264.7 cells to respond to infection by these mutants was scrutinised. Sixteen individual cytokines were profiled with mouse cytokine screen multiplex analysis. Signature cytokine profiles were observed that could again separate the different YopD mutants into distinct categories. The activation and supression of certain cytokines that function as central innate immune response modulators correlated well with the ability of mutant bacteria to modulate programmed cell death and antiphagocytosis pathways. Hence, the biogenesis of sub-optimal translocon pores alters host cell responsiveness and limits the ability of Yersinia to fortify against attack by both early and late arms of the host innate immune response.

    The amount of bacteria now resistant to multiple antibiotics is alarming. By providing insights into a common virulence process, this work may ultimately facilitate the design of novel broad-acting inhibitors of type III secretion, and thereby be useful to treat an array of bacterial infections.

  • Lennelöv, E.
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Section of Medicine.
    Irewall, Tommie
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Section of Medicine.
    Naumburg, Estelle
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Paediatrics.
    Lindberg, A.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Section of Medicine.
    Stenfors, Nikolai
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Section of Medicine.
    The Prevalence of Asthma and Respiratory Symptoms among Cross-Country Skiers in Early Adolescence.2019In: Canadian Respiratory Journal, ISSN 1916-7245, Vol. 2019, article id 1514353Article in journal (Refereed)
    Abstract [en]

    Objective. To determine the prevalence of asthma and respiratory symptoms among Swedish cross-country skiers in early adolescence in comparison to a population-based reference group of similar ages. Methods. A postal questionnaire on asthma, asthma medication, allergy, respiratory symptoms, and physical activity was distributed to Swedish competitive cross-country skiers aged 12–15 years (n = 331) and a population-based reference group (n = 1000). The level of asthma control was measured by the Asthma Control Test. Results. The response rate was 27% (n = 87) among skiers and 29% (n = 292) in the reference group. The prevalence of self-reported asthma (physician-diagnosed asthma and use of asthma medication in the last 12 months) and the prevalence of reported wheezing during the last 12 months were 23% and 25%, respectively, among skiers, which were significantly higher than the values reported in the reference group (12% and 14%). Skiers exercised more hours/week than the reference group. Among adolescents with self-reported asthma, neither the usage of asthma medications nor the level of asthma control according to the Asthma Control Test differed between skiers and the reference group. Conclusions. Adolescent competitive cross-country skiers have an increased prevalence of respiratory symptoms and asthma compared to nonskiers.

  • Eriksson, Martin
    Umeå University, Faculty of Social Sciences, Unit of Economic History.
    Mellan äganderätt och skatteförmåga: 1959 års arvsskattelagstiftning i ekonomisk-historisk belysning2019In: 1959 års ekonomiska historia: en festskrift i samband med professor Lena Andersson-Skogs 60-årsdag 2019 / [ed] Helén Strömberg, Umeå: Enheten för ekonomisk historia, Umeå universitet , 2019, p. 13-17Chapter in book (Other academic)
  • Wallner, Bengt
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences.
    Björ, Ove
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Oncology.
    Andreasson, Anna
    Vieth, Michael
    Schmidt, Peter T.
    Hellstrom, Per M.
    Forsberg, Anna
    Talley, Nicholas J.
    Agreus, Lars
    Z-line alterations and gastroesophageal reflux: an endoscopic population-based prospective cohort study2019In: Scandinavian Journal of Gastroenterology, ISSN 0036-5521, E-ISSN 1502-7708, Vol. 54, no 9, p. 1065-1069Article in journal (Refereed)
    Abstract [en]

    Background and study aims: Barrett's esophagus is a premalignant condition in the distal esophagus associated with esophageal adenocarcinoma. Since gastroesophageal reflux is known to be of etiological importance in both Barrett's esophagus and esophageal adenocarcinoma, we aimed to study which endoscopic alterations at the Z-line can be attributed to a previous history of reflux symptoms. Patients and methods: From 1988, a population cohort in Sweden has been prospectively studied regarding gastrointestinal symptoms, using a validated questionnaire. In 2012, the population was invited to undergo a gastroscopy and participate in the present study. In order to determine which endoscopic alterations that can be attributed to a previous history of gastroesophageal reflux, three different endoscopic definitions of columnar-lined esophagus (CLE) were used: (1) ZAP I, An irregular Z-line with a suspicion of tongue-like protrusions; (2) ZAP II/III, Distinct, obvious tongues of metaplastic columnar epithelium; (3) CLE >= 1 cm, The Prague C/M-classification with a minimum length of 1 cm. Results: A total of 165 community subjects were included in the study. Of these, 40 had CLE >= 1 cm, 99 had ZAP I, and 26 had ZAP II/III. ZAP II/III was associated with an over threefold risk of previous GER symptoms (OR: 3.60, CI: 1.49-8.70). No association was found between gastroesophageal reflux and ZAP I (OR: 2.06, CI: 0.85-5.00), or CLE >= 1 cm (OR: 1.64, CI: 0.77-3.49). Conclusions: In a general community, the only endoscopic alteration to the Z-line definitely linked to longstanding GER symptoms was the presence of obvious tongues of metaplastic columnar epithelium (ZAP II/III).

  • Dong, Xiaowei
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Mendoza-Trejo, Omar
    Morales, Daniel Ortiz
    Lindroos, Ola
    La Hera, Pedro
    Simulation-based comparison between two crane-bunk systems for loading work when considering energy-optimal motion planning2019In: International Journal of Forest Engineering, ISSN 1494-2119, E-ISSN 1913-2220Article in journal (Refereed)
    Abstract [en]

    Performing work for extended periods of time while using the lowest amount of resources is an important aspect for productivity in many industries. In forestry, the productivity of a forwarder is seen as the volume of material it can extract to a roadside landing in a certain amount of time, where the process of loading and unloading logs represents a large part of the work. During this process, the esnergy consumed by the machine is directly related to the speed of the crane. Thus, increasing productivity implies increasing the operating velocity of cranes. But according to current design of forestry cranes, this conversely leads to an undesired increase in consumption of resources (e.g. fuel). A second method is to alter the machine's design, such as rotating the log bunk. This article considers both methods through a simulation-based comparison aiming to evaluate the energy consumption of two crane-bunk systems when loading. The first simulation system considers a forestry crane with a fixed log bunk (forwarder-like crane). The second simulation system takes into account a forestry crane and a rotating log bunk (harwarder-like crane). The analysis presented considers the fundamental mathematics required to analyze the dynamics of forestry cranes and the principles required to plan energy-optimal motions. The simulation results show that energy savings of 43% to 61% can be obtained by determining energy-optimal motions and using a harwarder-like crane architecture.

  • Johansen, Tom
    Umeå University, Faculty of Arts, Department of culture and media studies.
    Maskulinitetsnormer i snowboardvärlden2019Independent thesis Basic level (degree of Bachelor), 180 HE creditsStudent thesis
    Abstract [sv]

    Syftet med denna studie är att undersöka hur maskulinitetsnormer produceras och reproduceras inom snowboardvärlden. Med snowboardvärlden och snowboardindustrin syftar jag på företag, personer, medier och andra som har inflytande inom snowboardbranschen. Genom teorier om maskulinitet och begrepp som genus och normer görs en kritisk kulturanalys av materialet som visar hur maskulinitetsnormer är något som påverkar alla snowboardåkare, oavsett kön. Materialet innefattar en beskrivning av snowboardåkningens historia,  studier av hur snowboardprodukter designas och marknadsförs och hur de både producerar och reproducerar maskulinitetsnormer. I studien visas hur exempelvis snowboardfilmer reproducerar maskulinitetsnormer samt hur den inneboende sexism som finns inom snowboardvärlden är tecken på en rådande hegemonisk maskulinitet. Studien visar även hur kvinnliga snowboardåkare-, snowboardfilmer- och snowboardtillverkare väljer att göra motstånd och förändra snowboardvärlden genom att utmana dessa normer.

  • Olsson, Michelle Astrid
    Umeå University, Faculty of Arts, Department of culture and media studies.
    Kulturkompisar: En kulturanalytisk undersökning om ett kultur- och integrationsprojekt2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Syftet med uppsatsen är att undersöka hur projektet Kulturkompis konstrueras inom ramarna för integrationstänkande och kulturupplevelser. Både utifrån de deltagandes perspektiv och upplevelser men också utifrån verksamhetens interna syn och arbete. Bland annat fokuserar studien på hur maktpositioner, föreställningar och normer produceras och reproduceras. Uppsatsen bygger på fem stycken kvalitativa intervjuer. Frågeställningarna jag sökt svar på är vilka normer om integration, kultur och gemenskap som kommer till uttryck i projektet. Analysen har utgått från konstruktivistiska perspektiv och begrepp som kultur, makt och klass.

  • Norberg, Helena
    et al.
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Pharmacology. Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine.
    Bergdahl, Ellinor
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine.
    Lindmark, Krister
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine.
    Safety and Tolerability of Initiating Maximum-Dose Sacubitril-Valsartan in Patients on Target Dose Renin-Angiotensin System Inhibitors2019In: Cardiovascular Therapeutics, ISSN 1755-5914, Vol. 2019, article id 6745074Article in journal (Refereed)
    Abstract [en]

    Aim. Sacubitril-valsartan has proven beneficial in heart failure with reduced ejection fraction. Guidelines recommend initiating half-dose sacubitril-valsartan before up-titration even to patients already on target dose angiotensin-converting enzyme (ACE) inhibitors or angiotensin receptor blockers (ARB). To reduce the number of titration steps needed in order to simplify for the patient as well as the clinic, we aimed to investigate the safety and tolerability of switching patients on target dose ACE inhibitors or ARBs directly to maximum-dose sacubitril-valsartan. Methods. This prospective cohort study was conducted between April 2016 and November 2017. A total of 66 patients with heart failure and reduced ejection fraction already on guideline-recommended target dose ACE inhibitors or ARBs (equivalent to enalapril 10 mg twice daily) were switched to maximum-dose sacubitril-valsartan (200 mg twice daily). The patients were followed for twelve months. Results. Patients had a mean age of 72 +/- 10 years, mean systolic blood pressure of 121 +/- 17 mmHg, and 92% were male. At 12-month follow-up, nine patients (14%) had discontinued sacubitril-valsartan, four patients (6%) had a dose reduction, and 17 patients (26%) had developed symptomatic hypotension. No angioedema occurred within the 12-month follow-up and there were no hospitalizations or emergency room visits within the first 14 days. Conclusions. Switching directly from target dose ACE inhibitors or ARBs to maximum-dose sacubitril-valsartan was safe and generally well tolerated.

  • Olofsson, Anton
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Evaluering av självlåsande gängor2019Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Thread-locking adhesive is a common component for many manufacturers, due to its protection against vibrations and slipping in screw joints. However, this does not work as desired on stainless steel materials. The purpose of this work is to evaluate if self-locking threads can replace thread locking adhesive to ensure the quality in the screw joints and reduce assembly times.

    In this work, a method for testing the loosening torque has been designed, manufactured and implemented for self-locking threads (SELF-LOCK) and for threads with standard base profile and thread-locking adhesive (Loctite) applied. The design applied to the test consists of a disc of stainless steel with a thickness of 26 mm. The disc is machined with threaded holes for SELF-LOCK threads and threads with standard base profile. The sizes of the holes are M6, M8, M10, M12 and M16. All sizes are applied for both thread locking systems.

    The test is based on investigating the two different thread-locking systems loosening torque in the case of pre-tensioned joints, with a bias of 73% of the yield strength for 8.8 strength class.

    Measuring equipment in this test is a digital spring scale attached to a joint breaker bar. The distance from the screw center to the spring scale attachment to the joint breaker bar is 290 mm.

    All screws are mounted with an axial bearing between the goods and the screw head in order to ignore the screw head friction.

    After analysis of the result, it can be noted that SELF-LOCK threads do not provide higher loosening torques than coarse pitch metric threads with Loctite applied. The difference in percentages falls to an average of 12% higher to Loctite's advantage. However, the comparison analysis shows an advantage for SELF-LOCK where among other things, the assembly time for retrieving and applying Loctite took 23 seconds. Which is the time that can be saved if SELF-LOCK is implemented.

    Although the SELF-LOCK threads did not meet the requirement for loosening torques, I still want to see that this is further investigated due to the fact that the SELF-LOCK system is, among other things, better in environmental and work environment viewpoints, and also in terms of time. This gives great benefits to people who work in production where Loctite is used, but it can also provide economic benefits for the company on a long-term basis. For example, a more economical overview should be included in a wider investigation as well as more tests of mechanical properties such as vibration tests should be carried out.

  • Wang, Xiaolei
    et al.
    Qu, Mingli
    Li, Jing
    Danielson, Patrik
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Ophthalmology. Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB).
    Yang, Lingling
    Zhou, Qingjun
    Induction of Fibroblast Senescence During Mouse Corneal Wound Healing2019In: Investigative Ophthalmology and Visual Science, ISSN 0146-0404, E-ISSN 1552-5783, Vol. 60, no 10, p. 3669-3679Article in journal (Refereed)
    Abstract [en]

    PURPOSE. To investigate the presence and role of fibroblast senescence in the dynamic process of corneal wound healing involving stromal cell apoptosis, proliferation, and differentiation.

    METHODS. An in vivo corneal wound healing model was performed using epithelial debridement in C57BL/6 mice. The corneas were stained using TUNEL, Ki67, and alpha-smooth muscle actin (alpha-SMA) as markers of apoptosis, proliferation, and myofibroblastic differentiation, respectively. Cellular senescence was confirmed by senescence-associated beta-galactosidase (SA-beta-gal) staining and P16(Ink4a) expression. Mitogenic response and gene expression were compared among normal fibroblasts, H2O2-induced senescent fibroblasts, and TGF-beta-induced myofibroblasts in vitro. The senescence was further detected in mouse models of corneal scarring, alkali burn, and penetrating keratoplasty (PKP).

    RESULTS. The apoptosis and proliferation of corneal stromal cells were found to peak at 4 and 24 hours after epithelial debridement. Positive staining of SA-beta-gal was observed clearly in the anterior stromal cells at 3 to 5 days. The senescent cells displayed P16(Ink4a) thorn vimentin+ alpha-SMA+, representing the major origin of activated corneal resident fibroblasts. Compared with normal fibroblasts and TGF-beta-induced myofibroblasts, H2O2-induced senescent fibroblasts showed a nonfibrogenic phenotype, including a reduced response to growth factor basic fibroblast growth factor (bFGF) or platelet-derived growth factor-BB (PDGF-BB), increased matrix metalloproteinase (MMP) 1/3/13 expression, and decreased fibronectin and collagen I expression. Moreover, cellular senescence was commonly found in the mouse corneal scarring, alkali burn, and PKP models.

    CONCLUSIONS. Corneal epithelial debridement induced the senescence of corneal fibroblasts after apoptosis and proliferation. The senescent cells displayed a nonfibrogenic phenotype and may be involved in the self-limitation of corneal fibrosis.

  • Westin, Love
    Umeå University, Faculty of Social Sciences, Umeå School of Business and Economics (USBE), Economics.
    Utilizing short-term noise in non-efficient markets by paired assets: -Introducing the Technical AMH trader2019Independent thesis Advanced level (degree of Master (Two Years)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    In this paper, we present an algorithmic implementation of a pairs trading strategy on the OMXS during the years from 2010 until 2018. In our case, the trading algorithm is based on the Adaptive Market Hypothesis (AMH) theory. Hence, the algorithm scans the market for temporary inefficient behaviour, as defined by AMH. The pairs trading algorithm suggested in the paper revolves around a minimum distance paring method that evaluates different threshold measures. In the paper, we also suggest a new method for the choice of threshold as well as evaluate the efficiency of the strategy by an application on the relatively small Swedish OMXS stock exchange. In this small exchange, other forms of market inefficiency may arise compared with those on a larger international stock exchange. The paper also presents the AMH framework for behaviour in a financial market, a hypothesis that may explain the positive result of the presented application of pairs trading strategy. Hence, this paper connects AMH with the pairs trading strategy. Our result indicates that when we exercise the strategy during a period of trading, in a portfolio consisting of 10 pairs, it generates a positive aggregated return, compared with index, even when we consider a theoretical transaction cost. Furthermore, the strategy outperforms a random naïve trading strategy combined with a low market dependence, measured in correlation. However, even if the strategy is profitable, the return is volatile. This is believed to be an outcome of volatile market reactions to new information in the close chosen substitutes. Such problems with pairing and diversity may be traced back to the small sample of stocks in the example presented in the paper. As such, the algorithm suggested is as a step towards trading based on theoretically motivated algorithmic learning models, in line with trading models developed within the rapidly emerging field of artificial intelligence.

  • de Loisted, André
    Umeå University, Faculty of Arts, Department of historical, philosophical and religious studies.
    Den svenskspråkiga arbetarrörelsen i Finland 1904 – 1906 i tidningen Arbetaren2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
  • Public defence: 2019-12-05 13:00 MA121, Umeå
    Ostovar, Ahmad
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Object Detection and Recognition in Unstructured Outdoor Environments2019Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Computer vision and machine learning based systems are often developed to replace humans in harsh, dangerous, or tedious situations, as well as to reduce the required time to accomplish a task. Another goal is to increase performance by introducing automation to tasks such as inspections in manufacturing applications, sorting timber during harvesting, surveillance, fruit grading, yield prediction, and harvesting operations.Depending on the task, a variety of object detection and recognition algorithms can be applied, including both conventional and deep learning based approaches. Moreover, within the process of developing image analysis algorithms, it is essential to consider environmental challenges, e.g. illumination changes, occlusion, shadows, and divergence in colour, shape, texture, and size of objects.

    The goal of this thesis is to address these challenges to support development of autonomous agricultural and forestry systems with enhanced performance and reduced need for human involvement.This thesis provides algorithms and techniques based on adaptive image segmentation for tree detection in forest environment and also yellow pepper recognition in greenhouses. For segmentation, seed point generation and a region growing method was used to detect trees. An algorithm based on reinforcement learning was developed to detect yellow peppers. RGB and depth data was integrated and used in classifiers to detect trees, bushes, stones, and humans in forest environments. Another part of the thesis describe deep learning based approaches to detect stumps and classify the level of rot based on images.

    Another major contribution of this thesis is a method using infrared images to detect humans in forest environments. To detect humans, one shape-dependent and one shape-independent method were proposed.

    Algorithms to recognize the intention of humans based on hand gestures were also developed. 3D hand gestures were recognized by first detecting and tracking hands in a sequence of depth images, and then utilizing optical flow constraint equations.

    The thesis also presents methods to answer human queries about objects and their spatial relation in images. The solution was developed by merging a deep learning based method for object detection and recognition with natural language processing techniques.

  • Strömberg, Helén
    Umeå University, Faculty of Social Sciences, Unit of Economic History.
    Barnmorskekrisen–ett nytt fenomen?2019In: 1959 års ekonomiska historia: en festskrift i samband med professor Lena Andersson-Skogs 60-årsdag 2019 / [ed] Helén Strömberg, Umeå: Enheten för ekonomisk historia, Umeå universitet , 2019, 21, p. 18-22Chapter in book (Other academic)
  • Stange, Eduard F.
    et al.
    Schröder, Björn
    Umeå University, Faculty of Medicine, Department of Molecular Biology (Faculty of Medicine). Umeå University, Faculty of Medicine, Molecular Infection Medicine Sweden (MIMS).
    Microbiota and mucosal defense in IBD: an update2019In: Expert Review of Gastroenterology & Hepatology, ISSN 1747-4124, E-ISSN 1747-4132, Vol. 13, no 10, p. 963-976Article in journal (Refereed)
    Abstract [en]

    Introduction: Inflammatory bowel diseases (IBD) are on the rise worldwide. This review covers the current concepts of the etiology of Crohn?s disease and ulcerative colitis by focusing on an unbalanced interaction between the intestinal microbiota and the mucosal barrier. Understanding these issues is of paramount importance for the development of targeted therapies aiming at the disease cause.

    Area covered: Gut microbiota alterations and a dysfunctional intestinal mucosa are associated with IBD. Here we focus on specific defense structures of the mucosal barrier, namely antimicrobial peptides and the mucus layer, which keep the gut microbiota at a distance under healthy conditions and are defective in IBD.

    Expert commentary: The microbiology of both forms of IBD is different but characterized by a reduced bacterial diversity and richness. Abundance of certain bacterial species is altered, and the compositional changes are related to disease activity. In IBD the mucus layer above the epithelium is contaminated by bacteria and the immune reaction is dominated by the antibacterial response. Human genetics suggest that many of the basic deficiencies in the mucosal response, due to Paneth cell, defensin and mucus defects, are primary. Nutrition may also be important but so far there is no therapy targeting the mucosal barrier.

  • Frykholm, Erik
    et al.
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Section of Physiotherapy.
    Pereira Lima, Vanessa
    Selander, Hanna-Vega
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Section of Physiotherapy.
    Nyberg, Andre
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Section of Physiotherapy.
    Janaudis-Ferreira, Tania
    Physiological and Symptomatic Responses to Arm versus Leg Activities in People with Chronic Obstructive Pulmonary Disease: A Systematic Review and Meta-Analysis2019In: COPD: Journal of Chronic Obstructive Pulmonary Disease, ISSN 1541-2555, E-ISSN 1541-2563Article in journal (Refereed)
    Abstract [en]

    While the mechanisms underlying exercise limitations and symptoms during leg activities have been investigated in detail, knowledge of potential differences between leg and arm activities are not well understood and results from individual studies are contradictory. Thus, the aim of the present study was to synthesize physiological and symptomatic responses during activities involving the arms relative to activities involving the legs in people with Chronic Obstructive Pulmonary Disease (COPD). Any study with a cross-sectional comparison of acute physiological (cardiorespiratory, metabolic) and symptomatic responses to activities performed with the arms versus the legs were included. Studies were sub-grouped based on the type of activity performed (cycle ergometer, resistance exercises, or functional test/activities). Eighteen studies with 423 individuals with COPD were included. Leg cycle ergometer resulted in greater tidal volume (137?mL), minute ventilation (4.8?L/min), and oxygen consumption (164?mL/min) than arm cycle ergometer, while symptomatic responses were similar. Resistance exercises resulted in similar physiological and symptomatic responses irrespective of whether the legs or the arms were involved while studies on functional activities report different results depending on the type and intensity of the activity performed. With the exception of cycle ergometer activities, physiological and symptomatic responses do not seem to depend on whether the arms or the legs are used, but rather seem to be task and intensity dependent. These novel findings suggest, for example, that strategies used to increase exercise tolerance should not be dependent on whether the arms or the legs are used, but rather the intensity of specific activity performed.

  • Bohman, Magnus
    Spänningsfält i brytningstid: svensk agrarhistoria under 1950-talet2019Chapter in book (Other (popular science, discussion, etc.))
  • Jörgensen, Hans
    Umeå University, Faculty of Social Sciences, Unit of Economic History.
    Jan Rydström och händelserna runt Öst-ekonomiska byråns bildande 19592019In: 1959 års ekonomiska historia: en festskrift i samband med professor Lena Andersson-Skogs 60-årsdag 2019, Umeå: Enheten för ekonomisk historia, Umeå universitet , 2019, p. 24-30Chapter in book (Other academic)
  • Silander, Isak
    et al.
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Hausmaninger, Thomas
    Umeå University, Faculty of Science and Technology, Department of Physics. National Metrology Institute VTT MIKES, Finland.
    Forssén, Clayton
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Zelan, Martin
    Axner, Ove
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Gas equilibration gas modulation refractometry for assessment of pressure with sub-ppm precision2019In: Journal of Vacuum Science and Technology B: Nanotechnology and Microelectronics, ISSN 2166-2746, E-ISSN 2166-2754, Vol. 37, no 4, article id 042901Article in journal (Refereed)
    Abstract [en]

    Gas modulation refractometry (GAMOR) is a methodology that, by performing repeated reference assessments with the measurement cavity being evacuated while the reference cavity is held at a constant pressure, can mitigate drifts in dual Fabry-Perot cavity based refractometry. A novel realization of GAMOR, referred to as gas equilibration GAMOR, that outperforms the original realization of GAMOR, here referred to as single cavity modulated GAMOR (SCM-GAMOR), is presented. In this, the reference measurements are carried out by equalizing the pressures in the two cavities, whereby the time it takes to reach adequate conditions for the reference measurements has been reduced. This implies that a larger fraction of the measurement cycle can be devoted to data acquisition, which reduces white noise and improves on its short-term characteristics. The presented realization also encompasses a new cavity design with improved temperature stabilization and assessment. This has contributed to improved long-term characteristics of the GAMOR methodology. The system was characterized with respect to a dead weight pressure balance. It was found that the system shows a significantly improved precision with respect to SCM-GAMOR for all integration times. For a pressure of 4303 Pa, it can provide a response for short integration times (up to 10 min) of 1.5 mPa (cycle)1/2, while for longer integration times (up to 18 h), it shows an integration time-independent Allan deviation of 1mPa (corresponding to a precision, defined as twice the Allan deviation, of 0.5 ppm), exceeding the original SCM-GAMOR system by a factor of 2 and 8, respectively. When used for low pressures, it can provide a precision in the sub-mPa region; for the case with an evacuated measurement cavity, the system provided, for up to 40 measurement cycles (ca. 1.5 h), a white noise of 0.7 mPa (cycle)1/2, and a minimum Allan deviation of 0.15mPa. It shows a purely linear response in the 2.8-10.1 kPa range. This implies that the system can be used for the transfer of calibration over large pressure ranges with exceptional low uncertainty.

  • Larsson, Sara Marie
    et al.
    Hillarp, Andreas
    Hellstrom-Westas, Lena
    Domellöf, Magnus
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Paediatrics.
    Lundahl, Tom
    Andersson, Ola
    When age really matters: ferritin reference intervals during infancy revisited2019In: Scandinavian Journal of Clinical and Laboratory Investigation, ISSN 0036-5513, E-ISSN 1502-7686Article in journal (Refereed)
    Abstract [en]

    Infants are at risk for iron deficiency. Despite research advances, assessing iron stores during infancy remains a challenge to the clinician. Ferritin is the first-choice laboratory marker for measuring iron stores but it is today still unclear how to evaluate reference intervals among infants. We have studied Swedish infants (n = 456), born at term after normal pregnancies. Ferritin was measured at birth (umbilical cord sample), 48-72 h, 4 months and 12 months. Lower and upper reference interval limits were constructed as the 2.5th and 97.5th percentiles. By a large study population, we were able to use more stringent measures to avoid interference from the acute phase response than previous reports on ferritin reference intervals. When we used mathematical transformation we furthermore avoided potential information loss in precision and confirmed earlier reports of sex differences. At the lower reference interval limits there were small differences between sexes. For the higher limits, the differences were more pronounced in the older infant. At 0-3 d of age we observed a difference between the sexes of only 5% at the upper limits. The differences peaked at 12 months, where the boys' upper 97.5th percentile was 56% compared to girls.

  • Kleijberg, Max
    et al.
    Ahlberg, Beth Maina
    Macdonald, Alastair
    Lindqvist, Olav
    Umeå University, Faculty of Medicine, Department of Nursing. Department of Learning, Informatics, Management and Ethics, Karolinska Institutet, Stockholm, Sweden.
    Tishelman, Carol
    Navigating power dynamics in engaging communities in end-of-life issues?: Lessons learned from developing community-based intergenerational arts initiatives about death and loss2019In: Death Studies, ISSN 0748-1187, E-ISSN 1091-7683Article in journal (Refereed)
    Abstract [en]

    Lack of community engagement in end-of-life issues and age-segregation in Swedish society motivated us to develop Studio DöBra, a community-based intergenerational arts initiative to support community engagement in end-of-life issues and develop intergenerational meeting places. Representatives from several community organizations formed a project group with first author MK, to develop Studio DöBra. Based on analysis of exploratory interviews with professionals involved in other, similar initiatives and data from Studio DöBra development, we discuss challenges related to power dynamics in developing initiatives to engage communities in end-of-life issues, and how these can inform the development of similar initiatives.

  • Holmberg, Marc
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Life Time BoM: BoM-effektivisering ur ett Lean-perspektiv.2019Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Beskrivning och analys av ett effektiviseringsprojekt på Sanminas fabrik i Örnsköldsvik. Projektet ska effektivisera BoM-hanteringsprocessen primärt genom tre förändringar. 1: Införa en BoM istället för flera. 2: Datorstöd istället för manuell hante-ring. 3: En konform hantering för alla projekt. Analysen av projektet grundas påLean-principer. Centrala begrepp som Lean och BoM beskrivs. En kvalitativ studiegenomförs med en fokusgrupp bestående av komponentingenjörer. Resultatet fråndenna ligger till grund för analysen. Ny metodik tolkas som effektivare än gammalmetodik på alla tre relevanta punkter. Ny metodik löser dock inte alla de bristersom finns i den gamla processen. Detta då de verktyg avsedda för interna processerinte har större inverkan på externa problem. Förändringarna tolkas som ett steg moten mer Lean BoM-hanteringsprocess. Fullständig analys kommer kunna genomförasnär ny metodik är implementerad. Diskussion kring tolkning av data och osäkerhet i analys av densamma. Detta då datan är kvalitativ.

  • Skulason, Skuli
    et al.
    Parsons, Kevin J.
    Svanback, Richard
    Räsänen, Katja
    Ferguson, Moira M.
    Adams, Colin E.
    Amundsen, Per-Arne
    Bartels, Pia
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Bean, Colin W.
    Boughman, Janette W.
    Englund, Göran
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Gudbrandsson, Johannes
    Hooker, Oliver E.
    Hudson, Alan G.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Kahilainen, Kimmo K.
    Knudsen, Rune
    Kristjansson, Bjarni K.
    Leblanc, Camille A-L.
    Jonsson, Zophonias
    Öhlund, Gunnar
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Smith, Carl
    Snorrason, Sigurdur S.
    A way forward with eco evo devo: an extended theory of resource polymorphism with postglacial fishes as model systems2019In: Biological Reviews, ISSN 1464-7931, E-ISSN 1469-185X, Vol. 94, no 5, p. 1786-1808Article, review/survey (Refereed)
    Abstract [en]

    A major goal of evolutionary science is to understand how biological diversity is generated and altered. Despite considerable advances, we still have limited insight into how phenotypic variation arises and is sorted by natural selection. Here we argue that an integrated view, which merges ecology, evolution and developmental biology (eco evo devo) on an equal footing, is needed to understand the multifaceted role of the environment in simultaneously determining the development of the phenotype and the nature of the selective environment, and how organisms in turn affect the environment through eco evo and eco devo feedbacks. To illustrate the usefulness of an integrated eco evo devo perspective, we connect it with the theory of resource polymorphism (i.e. the phenotypic and genetic diversification that occurs in response to variation in available resources). In so doing, we highlight fishes from recently glaciated freshwater systems as exceptionally well‐suited model systems for testing predictions of an eco evo devo framework in studies of diversification. Studies on these fishes show that intraspecific diversity can evolve rapidly, and that this process is jointly facilitated by (i) the availability of diverse environments promoting divergent natural selection; (ii) dynamic developmental processes sensitive to environmental and genetic signals; and (iii) eco evo and eco devo feedbacks influencing the selective and developmental environments of the phenotype. We highlight empirical examples and present a conceptual model for the generation of resource polymorphism – emphasizing eco evo devo, and identify current gaps in knowledge.

  • Bottone, Anna
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Analyzing microplastics in soils: Evaluating canola oil extractions2019Independent thesis Advanced level (degree of Master (Two Years)), 40 credits / 60 HE creditsStudent thesis
    Abstract [en]

    Small fragments of artificial polymers (microplastics, MPs) has been reported for multiple environmental matrices from our planet. The omnipresent existence of these microplastics even in remote polar areas have raised concern about their potential environmental impacts and created a need for effective and standardized analytical methods targeting their detection in environmental samples. So far, no methods have been developed for detecting microplastics in organic-rich soils. In this master thesis, I evaluate two analytical methods (both based on canola oil extractions) targeting microplastics in two contrasting soil matrices; one mineral rich (sandy mineral soil from a Podzol) and the other by organic matter (sample from a Histosol). I hypothesize that the detection of microplastic has a bias that depends on specific plastic particle properties (size, polymer type and morphology) as well as on the organic content of soil samples. My results show that the recovery of added plastics is strongly dependent on particle size and diminishes with decreasing microplastics length. This result was repeated by both extraction approaches.  Polymer shape and soil characteristics (organic matter content) affect MPs recovery if oil extractions are conducted without pre-treatment (oxidation) step. Here, fibers proved most difficult to detect and low recoveries suggested that the method was not applicable to organic rich samples. The addition of a pretreatment step including oxidation with sodium hypochlorite improved recoveries for organic rich samples and removed the effect of soil type and polymer shape. Hence, the use of a pretreatment is essential to extract MPs from organic-rich soils, but it also decreases the overall recovery for all type of studied polymers and mostly fibers. My study suggests that there is a substantial bias when detecting MPs in soils that is causing a general underestimation, especially for small, fibrous particles in organic rich soils.

  • Norman, Jim
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    PEER TO PEER SYSTEM FOR COLLABORATIVE WORK Using version control and fixed merge pattern to ensure eventual consistency2019Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Th‘is paper addresses the possibility of using version control and fi€xed merge pa‹ttern to ensure eventual consistency for collaborative work tools. Where the version control is upheld by a vector clock and used to detect conflƒicts. Which in turn are solved by rolling back to the last common version before using fi€xed merge patt‹ern to create a new common version. In the fixed merge patt‹ern a score system is used to lose as li‹ttle work as possible. ‘This is then tested against a leader node solution for the collaborative work tools. Which upli‰fts a FIFO consistency to sequential consistency by forcing all updates to go through the leader. The test used is a speed test to see if it is a viable solution or not to use when dealing with weak network connection. Since it would require less messages to be sent over the network compared to a leader node solution.

  • Strömberg, Helén
    Umeå University, Faculty of Social Sciences, Unit of Economic History.
    1959 års ekonomiska historia: en festskrift i samband med professor Lena Andersson-Skogs 60-årsdag 20192019Collection (editor) (Other academic)
  • Landfors, Kristoffer
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    DETECTION AND RESOLUTION OF VSI-DDOS ATTACKS FOR CONTAINERIZED CLOUDS2019Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Very Short Intermi‹ent Distributed Denial of Service (VSI-DDoS) a‹ttack is a new form of DDoS a‹ttacks with potential to bypass many of the security measures used today and still severely damage the quality of service of web applications in cloud systems. Th‘e att‹acks consists of short bursts of legitimate packets which exploits vulnerabilities in the targeted system. With the growing popularity of using containers instead of Virtual Machines in clouds, this project presents an approach for detecting these a‹ttacks in a container based cloud system. Th‘e approach uses signal processing in the form of Discrete Wavelet Transform (DWT) and recurrent neural networks (RNN) called Long Short Term Memory (LSTM) to detect a‹ttacks. Several experiments have been carried out to evaluate the performance of the proposed approach in a controlled testbed environment and it is shown to perform well with competing approaches.