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This thesis deals with students' constructions of mathematical knowledge in the case of fractions from a radical constructivist perspective. Fractions are the first more abstracted mathematics met by students. Even if they have a rich experience of sharing and partitioning things in their everyday life dealing with fractions often give rise to difficulties in school. The thesis consists of two p
The first essay examines the outcome in a competitive private pension market characterised by adverse selection. In addition to using the private pension market, the consumers can save in a bequeathable asset. Assuming two types of agents and using the Coalition Proof Equilibrium with Private Information we show that the outcome in the private pension market may be separating or pooling. A separat
Popular Abstract in Swedish En av de stora vetenskapliga bedrifterna hittills under 2000-talet är onekligen att man efter många års arbete för första gången lyckades kartlägga (sekvensera) samtliga mänskliga gener. Det mänskliga DNA:t är lokaliserat till cellkärnan och i princip så kan man likna en cellkärna med ett kontrollrum fyllt av manualer (DNA) som talar om cellens sammansättning och hur deProteomics is expected to generate new insights into biological processes as well as identify novel biomarkers and therapeutic targets since most biological functions are transmitted through proteins. However, due to the complexity displayed by a proteome and inherent limitations associated with current methodologies, proteomic analyses often result in incomplete coverage and inconsistent measurem
The two nature reserves Benestads backar and Hagestad in Scania, southernmost Sweden, were surveyed for insect diversity during 2011 and 2012. Because current management plans for both reserves include a size expansion to increase the protective status also of adjacent areas, the aim of this survey was to derive a measure of current insect diversity in both reserves. These estimates can then be us
Popular Abstract in Swedish Kärleksdofter och varningsljud i bekämpning av nattfjärilar Jag har studerat hur populationer av skadegörande nattfjärilar kan bekämpas med miljövänliga metoder där djurens egna sinnessystem manipuleras. Liksom många andra insekter kommunicerar nattfjärilar med artspecifika doftsignaler (feromoner) vid parning. Honan avger doften i enstaka nanogram (miljarddels gram!) The impact of olfactory and auditory cues on the mating behaviour in two species of moths, Agrotis segetum (Noctuidae) and Plodia interpunctella (Pyralidae), was investigated to evaluate their potential use in integrated pest management. The flight behaviour of male A. segetum under natural and pheromone-based mating disruption conditions was monitored by harmonic radar. Individual males were equi
Chiral building blocks are needed for the production of drugs and fine chemicals, which requires the use of several synthetic routes to produce a specific enantiomer of interest. One promising approach to introduce chirality into molecules is the stereo-selective whole cell bioreduction of carbonyl compounds or ketones to the corresponding chiral alcohols. The aim of this thesis was to develop ef
The production of ethyl esters (EE) from ethanol and cod-liver oil by an immobilised lipase in supercritical carbon dioxide (SCCO2) is described. This reaction results in a complex mixture of lipid components consisting of triglycerides, diglycerides, monoglycerides and ethyl esters. The primary goal has been to carry out enzymatic reaction and product separation simultaneously, by selectively ext
Popular Abstract in Swedish Avhandlingen kretsar kring centralbankens möjligheter att kontrollera inflationstakten. Under senare tid har mycket forskning ägnats åt att analysera och utvärdera de institutionella förutsättningarna för centralbanker, såväl avseende graden av oberoende som vilka mål penningpolitiken bör inriktas mot; exempelvis direkta inflationsmål versus användandet av indirekta målAfter an introductory chapter, the hypothesis is made in chapter two: that central bank power to control the rate of inflation rests on the bank’s ability to achieve a role as a focal point for inflation. Inflation is a measure of changes in the general price level, the price level is an index of individual prices, and to predict future price levels is thus to predict future prices on individual i
Popular Abstract in Swedish Nya möjligheter att förutsäga sjukdomsutvecklingen vid tidig ledgångsreumatism. I denna avhandling presenteras resultaten från sex studier av patienter med tidig reumatoid artrit (RA) – ledgångsreumatism. Syftet med avhandlingen var att i det tidiga sjukdomsskedet, så snart som möjligt efter diagnos, försöka skaffa information om hur sjukdomen kommer att utvecklas - om Objective: To investigate the role of magnetic resonance imaging (MRI), assessment of bone mineral density (BMD) and antibodies to citrullinated proteins (anti-CCP) in predicting radiologic outcome in patients with early rheumatoid arthritis (RA). Patients: All patients were included in the BARFOT programme (baseline). The patients had rheumatoid arthritis of recent onset with mean disease duratio
Popular Abstract in Swedish Avhandlingen utreder några av konsekvenserna av de institutionella reformer som genomfördes i Sydafrika under 1990-talet, med särskilt fokus på det nya kommunsystemet, enligt vilket varje kommun är skyldig att stimulera lokal ekonomisk utveckling i samarbete med det lokal näringslivet och andra civilsamhälleliga aktörer. Den syftar även till att utveckla den samhällsvet
Drainage of peatlands increases the transport of suspended solids (SS) and the leaching of nutrients to downstream receiving waters. Increased settling of peat and eutrophication of lakes has been noted in many studies downstream from peat mines. Treatment alternatives have therefore been developed since the early 1980s to reduce the environmental impacts of peat mining. New, efficient methods suc
Popular Abstract in Swedish Sammanfattning Teknik är alltid skapad för en förväntad brukare i ett antaget sammanhang. Inom kommersiell luftfart är dessa antaganden när det gäller design tydliga. Såväl besättning som utrustning är certifierad för en viss typ av operationer i enlighet med flygplanets drifthandbok. Trots denna genomtänkta definition av användare i sitt sammanhang händer det ändå attAbstract Technology is always designed for an assumed user in an assumed context. In commercial aviation, these design assumptions are clearly spelt out in that both crew and equipment are certificated for a specific operation as stated in the aircraft flight manual. Despite this well defined user context, the designed-for and the real contexts often differ enough so that adaptations of working p
We present multiple-epoch radial-velocity observations for 104 stars in a field of the intermediate-age open cluster IC 4651 to . Only 13 stars (13%) of the full sample are field stars. From the 44 single member stars we find a mean radial velocity of , and the 12 single red-giant members yield a true radial-velocity dispersion of . Of the 19 giant members, 7 (37%) are spectroscopic binaries with
Background: Subjective Well-Being (SWB) is usually conceptualized in terms of an affective (i.e., judgements of biological emotional reactions and experiences) and a cognitive component (i.e., judgements of life satisfaction in relation to a psychological self-imposed ideal). Recently, researchers have suggested that judgements of harmony in life can replace or at least complement the cognitive co
Purpose: The local depth dose gradient and the displacement correction factor for Farmer-type ionization chambers are quantified for reference dosimetry at shallow depth in single-layer scanned proton fields. Method: Integrated radial profiles as a function of depth (IRPDs) measured at three proton therapy centers were smoothed by polynomial fits. The local relative depth dose gradient at measurem
Increasing CO₂ emission is considered as the main reason for global warming in the world. One of the reasons for producing CO₂ is using of fossil-based materials in the construction projects. This study intends to assess the using bio-based materials instead of fossil-based materials for the thermal insulation layer of the external walls and roofs. Another focus of this project is using green conc
To mitigate dangerous climate change, a transition to a new and sustainable energy system is needed. In this system, solar energy will need to be a key player. Prices of electricity made from solar cells have declined rapidly over the recent decades, making solar energy competitive in more markets. However, further price reductions and new innovations are needed for solar cell technology to fulfil
Importance: Quality of life is not a standard primary outcome in ablation trials, even though symptoms drive the indication.Objective: To assess quality of life with catheter ablation vs antiarrhythmic medication at 12 months in patients with atrial fibrillation.Design, Setting, and Participants: Randomized clinical trial at 4 university hospitals in Sweden and 1 in Finland of 155 patients aged 30
The access to safe and clean drinking water is a major concern throughout the world. Surface water has become the most common source for raw water, when large quantities of groundwater often are inaccessible, and as surface water requires more treatment, simple, cheap and efficient process methods are necessary. Turbidity removal is essential for treatment of surface water and is often carried out
