| 1. |
- Jacobsson, Amanda, et al.
(author)
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”Ambulanssjukvården behöver genomgripande förändringar”
- 2021
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In: Dagens Medicin. - : Dagens Medicin. - 1402-1943. ; :2021-06-23
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Journal article (pop. science, debate, etc.)abstract
- Debattörer från Ambulance health research network vill se en nationell ledningsstruktur, ökad evidens för vården, akademisk kompetens i ledningsfunktioner samt en nationell utbildnings- och kompetensstandard.
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| 2. |
- Persson, Jonas, 1976-
(author)
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Accurate Finite Difference Methods for Option Pricing
- 2006
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Doctoral thesis (other academic/artistic)abstract
- Stock options are priced numerically using space- and time-adaptive finite difference methods. European options on one and several underlying assets are considered. These are priced with adaptive numerical algorithms including a second order method and a more accurate method. For American options we use the adaptive technique to price options on one stock with and without stochastic volatility. In all these methods emphasis is put on the control of errors to fulfill predefined tolerance levels. The adaptive second order method is compared to an alternative discretization technique using radial basis functions. This method is not adaptive but shows potential in option pricing for one and several underlying assets. A finite difference method and a Monte Carlo method are applied to a new financial contract called Turbo warrant. A comparison of these two methods shows that for the case considered the finite difference method is superior.
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| 3. |
- Struckmann, Wiebke, 1991-
(author)
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The effect of intermittent theta-burst stimulation over the dorsomedial prefrontal cortext on brain activity in depression
- 2021
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Doctoral thesis (other academic/artistic)abstract
- Repetitive transcranial magnetic stimulation is an emerging alternative for treatment-resistant depression, with ongoing developments in stimulation protocols and treatment targets. As such, intermittent theta-burst stimulation (iTBS) delivered over the dorsomedial prefrontal cortex (dmPFC) has shown promise, however establishing a need for neuroimaging studies to further understand the treatment mechanisms. This thesis aims to explore the effects of dmPFC-iTBS on brain activity in depression, using data from a randomized controlled trial and two add-on brain imaging studies with shared methodology. Study I investigated the prefrontal blood oxygenation (oxy-Hb) response during, as well as before and after iTBS sessions at the first, fifth, and final day of treatment. Oxy-Hb was assessed using functional near-infrared spectroscopy (fNIRS). Study II examined patients’ cognitive performance and concurrent prefrontal oxy-Hb before and after a full iTBS treatment course, again using fNIRS. The patient data were also compared to a sample of healthy controls. Study III assessed whether iTBS modulates functional brain activity during an emotional picture anticipation paradigm, using functional magnetic resonance imaging (fMRI). Study IV investigated the functional connectivity of the brain network behind the oxy-Hb response observed in study I. This was done by using the fNIRS optode locations as seeds in a resting-state fMRI analysis before and after a full iTBS treatment course. In summary, brain activity was modulated by iTBS both in an acute and delayed matter. Patients receiving active iTBS had increased prefrontal oxy-Hb levels during the fifth and final iTBS session, suggesting that this modulation was being built up during the treatment course (study I). Resting-state functional connectivity of this prefrontal cortex region to the insula or, when adding oxy-Hb change as a regressor, the posterior parietal cortex was modulated after active, but not sham, iTBS (study IV). Likewise, amygdala activation during exposure to picture stimuli of negative valence was reduced after active, but not sham, iTBS (study III). While patients displayed cognitive deficits compared to healthy controls before treatment start, active iTBS did not alter their cognitive performance or concurrent prefrontal oxy-Hb (study II).
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| 4. |
- Bengtsson, Peder
(author)
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Increasing the value of household appliances by adding a heat pump system
- 2014
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Licentiate thesis (other academic/artistic)abstract
- Historically, domestic tasks such as preparing food and washing and drying clothes and dishes were done by hand. In a modern home many of these chores are taken care of by machines such as washing machines, dishwashers and tumble dryers. When the first such machines came on the market customers were happy that they worked at all! Today, the costs of electricity and customers’ environmental awareness are high, so features such as low electricity, water and detergent use strongly influence which household machine the customer will buy. One way to achieve lower electricity usage for the tumble dryer and the dishwasher is to add a heat pump system.The function of a heat pump system is to extract heat from a lower temperature source (heat source) and reject it to a higher temperature sink (heat sink) at a higher temperature level. Heat pump systems have been used for a long time in refrigerators and freezers, and that industry has driven the development of small, high quality, low price heat pump components. The low price of good quality heat pump components, along with an increased willingness to pay extra for lower electricity usage and environmental impact, make it possible to introduce heat pump systems in other household products.However, there is a high risk of failure with new features. A number of household manufacturers no longer exist because they introduced poorly implemented new features, which resulted in low quality and product performance. A manufacturer must predict whether the future value of a feature is high enough for the customer chain to pay for it. The challenge for the manufacturer is to develop and produce a high-performance heat pump feature in a household product with high quality, predict future willingness to pay for it, and launch it at the right moment in order to succeed.Tumble dryers with heat pump systems have been on the market since 2000. Paper I reports on the development of a transient simulation model of a commercial heat pump tumble dryer. The measured and simulated results were compared with good similarity. The influence of the size of the compressor and the condenser was investigated using the validated simulation model. The results from the simulation model show that increasing the cylinder volume of the compressor by 50% decreases the drying time by 14% without using more electricity. Paper II is a concept study of adding a heat pump system to a dishwasher in order to decrease the total electricity usage. The dishwasher, dishware and water are heated by the condenser, and the evaporator absorbs the heat from a water tank. The majority of the heat transfer to the evaporator occurs when ice is generated in the water tank. An experimental setup and a transient simulation model of a heat pump dishwasher were developed. The simulation results show a 24% reduction in electricity use compared to a conventional dishwasher heated with an electric element. The simulation model was based on an experimental setup that was not optimised. During the study it became apparent that it is possible to decrease electricity usage even more with the next experimental setup.
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| 5. |
- Frick, Andreas, Docent, et al.
(author)
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Habitual caffeine consumption moderates the antidepressant effect of dorsomedial intermittent theta-burst transcranial magnetic stimulation
- 2021
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In: Journal of Psychopharmacology. - : Sage Publications. - 0269-8811 .- 1461-7285. ; 35:12, s. 1536-1541
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Journal article (peer-reviewed)abstract
- Background:Potentiating current antidepressant treatment is much needed. Based on animal studies, caffeine may augment the effects of currently available antidepressants.Objective:Here, we tested whether habitual caffeine consumption moderates the antidepressant effects of repetitive transcranial magnetic stimulation (rTMS) using intermittent theta-burst stimulation (iTBS).Methods:Forty patients with current depressive episodes were randomized to active iTBS (n = 19) or sham treatment (n = 21; shielded side of the coil and weak transcutaneous electrical stimulation) delivered two times per day for 10–15 weekdays. Neuronavigated stimulation was applied to the dorsomedial prefrontal cortex. Symptom improvement was measured using change in self-reported Montgomery-Åsberg Depression Rating Scale (MADRS) scores. Pretreatment habitual caffeine consumption was quantified using self-reports of number of cups of coffee and energy drinks consumed the 2 days before the treatment starts.Results:Habitual caffeine consumption was associated with symptom improvement following active iTBS (r = 0.51, 95% confidence interval (CI): 0.08–0.78, p = 0.025) but not following sham treatment (r = −0.02, 95% CI: −0.45 to 0.42, p = 0.938). A multiple regression analysis corroborated the findings by showing a significant caffeine consumption × treatment group interaction (β = 0.62, p = 0.043), but no main effects of treatment group (β = 0.22, p = 0.140) or caffeine consumption (β = −0.01, p = 0.948). No group differences in pretreatment symptom scores or caffeine consumption were detected (p values > 0.86).Conclusion:Habitual caffeine consumption moderated the antidepressant effect of dorsomedial iTBS, consistent with caffeine improving antidepressant pharmacological treatments in animals. Caffeine is an antagonist of adenosine receptors and may enhance antidepressant effects through downstream dopaminergic targets.
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| 6. |
- Kauppi, Karolina, 1985-
(author)
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Genes to remember : imaging genetics of hippocampus-based memory functions
- 2013
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Doctoral thesis (other academic/artistic)abstract
- In the field of imaging genetics, brain function and structure are used as intermediate phenotypes between genes and cognition/diseases to validate and extend findings from behavioral genetics. In this thesis, three of the strongest candidate genes for episodic memory, KIBRA, BDNF, and APOE, were examined in relation to memory performance and hippocampal/parahippocampal fMRI blood-oxygen level-dependent (BOLD) signal. A common T allele in the KIBRA gene was previously associated with superior memory, and increased hippocampal activation was observed in noncarriers of the T allele which was interpreted as reflecting compensatory recruitment. The results from the first study revealed that both memory performance and hippocampal activation at retrieval was higher in T allele carriers (study I). The BDNF 66Met and APOE ε4 alleles have previously been associated with poorer memory performance, but their relation to brain activation has been inconsistent with reports of both increased and decreased regional brain activation relative to noncarriers. Here, decreased hippocampal/parahippocampal activation was observed in carriers of BDNF 66Met (study II) as well as APOE ε4 (study III) during memory encoding. In addition, there was an additive gene-gene effect of APOE and BDNF on hippocampal and parahippocampal activation (study III). Collectively, the results from these studies on KIBRA, BDNF, and APOE converge on higher medial temporal lobe activation for carriers of a high-memory associated allele, relative to carriers of a low-memory associated allele. In addition, the observed additive effect of APOE and BDNF demonstrate that a larger amount of variance in BOLD signal change can be explained by considering the combined effect of more than one genetic polymorphism. These imaging genetics findings support and extend previous knowledge from behavioral genetics on the role of these memory-related genes.
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| 7. |
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| 8. |
- Persson, Tomas, Lektor, 1970-
(author)
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De naturvetenskapliga ämnesspråken : De naturvetenskapliga uppgifterna i och elevers resultat från TIMSS 2011 år 8
- 2016
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Doctoral thesis (other academic/artistic)abstract
- This thesis examines the scientific language in different subjects by analysing all grade 8 science items from TIMSS 2011, using four characteristic meaning dimensions of scientific language – Packing, Precision and Presentation of information, and the level of Personification in a text. The results, as well as results from established readability measures, are correlated with test performances of different student groups. The TIMSS vocabulary is compared with three Swedish corpora where low frequency words are identified and further analysed.The thesis challenges the notion that there is a single scientific language, as results show that the language use varies between subjects. Physics uses more words, biology shows higher Packing and lower Precision, while physics shows the opposite pattern. Items are generally low in Personification but physics has higher levels, earth science lower. Chemistry often presents information in more complex ways.The use of meaning dimensions manages to connect the language use in science items to student performance, while established measures do not. For each subject, one or more of the meaning dimensions shows significant correlations with small to medium effect sizes. Higher Packing is positively correlated with students’ results in earth science, negatively correlated in physics, and has no significant correlations in biology or chemistry. Students’ performances decrease when placing items in everyday contexts, and skilled readers are aided by higher precision, while less-skilled seem unaffected. Many meaning dimensions that influence low performers’ results do not influence those of high performers, and vice versa.The vocabulary of TIMSS and school textbooks are closely matched, but compared with more general written Swedish and a more limited vocabulary, the coverage drops significantly. Of the low frequency words 78% are nouns, where also most compound–, extra long– and made-up words are found. These categories and nominalisations are more common in biology and, except for made-up words, rare in chemistry. Abstract and generalizing nouns are frequent in biology and earth science, concrete nouns in chemistry and physics.
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| 9. |
- Pudas, Sara, 1983-
(author)
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Brain characteristics of memory decline and stability in aging : Contributions from longitudinal observations
- 2013
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Doctoral thesis (other academic/artistic)abstract
- Aging is typically associated with declining mental abilities, most prominent for some forms of memory. There are, however, large inter-individual differences within the older population. Some people experience rapid decline whereas others seem almost spared from any adverse effects of aging. This thesis examined the neural underpinnings of such individual differences by using longitudinal observations of episodic memory change across 15-20 years, combined with structural and functional magnetic resonance imaging of the brain. Study I found significant correlations between volume and activity of the hippocampus (HC), and memory change over a 6-year period. That is, individuals with decline in HC function also had declining memory. In contrast, Study II showed that successfully aged individuals, who maintained high memory scores over 15-20 years, had preserved HC function compared to age-matched elderly with average memory change. The successful agers had HC activity levels comparable to those of young individuals, as well as higher frontal activity. Study III revealed that individual differences in memory ability and brain activity of elderly reflect both differential age-related changes, and individual differences in memory ability that are present already in midlife, when age effects are minimal. Specifically, memory scores obtained 15-20 years earlier reliably predicted brain activity in memory-relevant regions such as the frontal cortex and HC. This observation challenges results from previous cross-sectional aging studies that did not consider individual differences in cognitive ability from youth. Collectively the three studies implicate HC and frontal cortex function behind heterogeneity in cognitive aging, both substantiating and qualifying previous results from cross-sectional studies. More generally, the findings highlight the importance of longitudinal estimates of cognitive change for fully understanding the mechanisms of neurocognitive aging.
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| 10. |
- Solares Canal, Carmen, 1987-
(author)
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The impact of criminal and externalizing behaviors on aging : Long-term associations with health and dementia
- 2024
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Doctoral thesis (other academic/artistic)abstract
- Previous studies have shown that criminal and other externalizing behaviors are associated with several adverse outcomes, but very little is known about the impact of these behaviors beyond middle adulthood. Few studies have explored how a life-course background of criminal and externalizing behaviors influence aging and more specifically, whether it is associated with the onset and development of different neurodegenerative, mental, and physical health disorders when aging. The overarching aim of this dissertation is to advance the knowledge about the long-term influence that criminal and other externalizing behaviors along the lifespan may have on health and neurodegeneration while individuals age. This aim was explored throughout three studies: Study I, a systematic review and meta-analysis performed to investigate the prevalence of several mental and physical health problems of older offenders; Study II, a Swedish population-based register study which examined how the severity of the criminal background associated with dementia and mild cognitive impairment (MCI), and how several life-course factors influenced these associations and; Study III, a multi-generation cohort study investigating whether externalizing behaviors and dementia co-aggregate in families. The main findings suggest that older adults with criminal and externalizing behavioral backgrounds, and overall, those with a severe criminal history, exhibit an increased liability to develop physical and mental health problems as well as MCI and dementia when aging. This increased risk is influenced by life-course health and psychosocial problems as well as genetic and familial environmental factors. In general, findings from this thesis point towards a better understanding of the aging process of individuals with this background, and to further the scientific knowledge about the influence of life-course adverse behaviors on aging. This knowledge may promote the development of preventive and interventive strategies for individuals with a criminal and externalizing behavioral background.
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