The quantum Hall effect occurs when a conductor carrying a current is placed in a perpendicular magnetic field. If certain conditions are met, such as strong magnetic field and low temperature, the resistivity becomes quantised, taking values of integer or fractional multiples of h/e2. By analysing the movement of electrons in a magnetic field classically and quantum mechanically information about the integer quantum Hall effect and the fractional quantum Hall effect can be gathered, using the two different gauge potentials of Landau gauge and Symmetric gauge. Resistance Metrology is one field of study that the quantum Hall effect has greatly impacted by providing a way to universally maintain the ohm, with significantly less uncertainty than previously. / Den kvantmekaniska hall-effekten uppstår när en strömbärande ledare placeras i ett vinkelrätt magnetfält. Om vissa villkor är uppfyllda, såsom starkt magnetfält och låg temperatur, blir resistiviteten kvantiserad. Given av heltal (integer) eller fraktions-(fractional) multiplar av h/e2. Genom att analysera elektroners rörelse i ett magnetfält klassiskt och kvantmekaniskt fås information om Hall-effekterna; integer quantum Hall effect och fractional quantum Hall effect, med hjälp av de två gauge potentialerna Landau gauge och Symmetrisk gauge. Resistansmetrologi är ett forskningsområde som kvant Hall-effekten har starkt påverkat genom att tillhandahålla ett sätt att universellt upprätthålla ohm-enheten med betydligt mindre osäkerhet än tidigare.

Först ges en beskrivning av undervsiningsfilosofin Investigative Science Learning Environment (ISLE) och research-based assessment instruments (RBAIerna) CLASS och ECLASS, följt av en översättning till svenska av RBAIerna. En analys skedde sedan av hur svaren till påståendena i RBAIerna (pre- vs post-) förväntas ändras om en ISLE-baserad undervisning ges. I analysen försökte jag koppla påståendena till någon eller några av de sex vetenskapliga förmågorna och deras tillhörande bedömningsmatriser, vilka nu är en integrerad komponent i ISLE filosofin, men som ursprungligen utvecklades av Rutgers Physics and Astronomy Education (PAER) group. Jag använde även litteratur om ISLE och textboken "College Physics: Explore and Apply", vilken används i ISLEbaserade kurser, för att analysera påståendena. Resultatet blev att en majoritet av alla påståenden - 72\% av CLASS- och 77\% av ECLASSpåståendena - bör besvaras mer expertlikt efter en ISLE-baserad undervisning än innan. Ett påstående i CLASS, vilket motsvarar 3\% av påståendena i enkäten bedömdes även besvaras mindre expertlikt och resterande kunde jag inte, utifrån min analysmetod förutsäga om de skulle besvaras mindre, lika eller mer expertlikt. Efter analysen och undersökningar av tidigare studier om studenters prestationer på CLASS- och ECLASSenkäterna, formulerades en förutsägelse att en ISLE-baserad undervisning bör leda till att elever svarar mer expertlikt än om de undervisas traditionellt. En pilotstudie av den svenska översättningen genomfördes sedan på elever inom olika utbildningsnivåer mellan gymnasie- och doktorandnivå. Resultatet analyserades och jämfördes med tidigare forskning i andra länder, även om både skillnader och likheter kunde hittas var det svårt att dra några generella slutsatser på grund av få svarande i min studie. / A description of the teaching philosophy Investigative Science Learning Environment (ISLE) and the research-based assessment instruments (RBAIs) CLASS and ECLASS are given, followed by a translation of the RBAIs into Swedish. An analysis is then made of how the answers to the RBAIs (pre- vs. post-) are expected to change if students take an ISLE-based physics course. In the analysis, I tried to connect the statements to one or more of the six scientific abilities and their associated rubrics, which are now a component of the ISLE philosophy but are originally developed by the Rutgers Physics and Astronomy Education (PAER) group. I did also use literature about ISLE and the textbook “College Physics: Explore and Apply” which is used in ISLE based courses, to analyze the statements. I found that that the majority of the statements - 72 \% in CLASS and 77 \% in ECLASS – are expected to be answered in a more expert-like way after an ISLE-based course. One statement in CLASS, which corresponds to 3 \% of the statements in the survey, is expected to be answered in a less expert-like way. For the rest of the statements I could not predict, using my method of analysis, if they would be answered less, equally or more expert-like.  After performing the analysis and examining the existing research literature on student performance on CLASS and ECLASS surveys, a prediction that ISLE-based teaching should lead to more expert-like answers than traditional teaching is formulated. Results from a recent empirical study done in the US, published after my analysis was complete, appear to be in agreement with the prediction that follows from my analysis. A pilot study of the Swedish translations of CLASS and ECLASS was also performed on students at different educational levels, ranging from upper secondary to doctoral level. The results were analyzed and compared to previous research in other countries. Although both differences and similarities could be found, it was not possible to draw any general conclusions due to the small number of respondents in my study.

Diskrepansen mellan inställningen gentemot fysik hos elever på gymnasiet i Europa och Nordamerika och arbetsmarknadens krav på kompetens inom naturvetenskapliga ämnen skapar utmaningar inför framtiden. Inställningen gentemot fysik har visat sig förbättras genom användandet av kollaborativt lärande och representationer. Rapporten syftar till att analysera svenska gymnasieelevers kommunikation i relation till deras identitet som fysiker samt hur de använder olika fysikaliska representationer i en kollaborativ kontext. Datan har insamlats genom gruppdiskussioner där elever tre och tre tillsammans löser kontextrika problem. Det visar sig att den matematiska representationen används frekvent och har en stark ställning i samtalen medan andra representationer som grafer och figurer snarare ses som hjälpmedel för lösningen. Den matematiska representationen ger även upphov till att respondenterna positionerar sig i samtalen som experter. Resultaten stärker tidigare forskningsresultat som påvisar matematikrepresentationens frekventa användning. / The discrepancy between the attitudes that students in upper secondary school has towards physics as a subject in Europe and North America and the labor market requirements of competence in science and technology creates challenges for future generations. The attitudes towards physics have shown to improve when different educational approaches of teaching, such as collaboration and the use of multiple representations have been applied. This report aims to analyse students in Swedish upper secondary schools communication in relation to their physics identity, as well as how they use multiple representations in a collaborative context. To analyse these relations, data has been gathered through group discussionss where students are encouraged to solve context-rich problems collaboratively. My findings shows that the mathematical representation is the most frequently used and also have a dominant position in relation to other representations such as graphs and figures, which are seen predominantly as an aid in forming the solution. When the students in the study utilize the mathematical representation they also tend to position themselves as experts. The findings are in line with previous research which have studied how students use multiple representations.

Tsirelson's bound is the upper bound for a Bell inequality which is valid for all quantum mechanical systems. We discuss why Tsirelson's bound was developed by looking at some historical arguments in quantum physics, such as the Einstein-Podolsky-Rosen (EPR) paradox, an argument for the quantum mechanical description of physical reality being incomplete, and local hidden variables. We present the counterargument to those theories, Bell's inequality, which later expanded to include any inequality that a local system fulfills, but that an entangled quantum system can violate. We present the proof of two specific Bell inequalities: the Clauser-Horne-Shimony-Holt (CHSH) inequality and the I3322 inequality. Then the Tsirelson's bound for the CHSH inequality is proven with a simple system of two entangled spin-1/2 particles and with a general argument that is valid for all entangled systems. We give the upper quantum bound for the generalized CHSH inequality, which describes the situation that we have more than two measurement options, by using semidefinite programming. We prove the Tsirelson's bound for the I3322 inequality by using maximally entangled systems and semidefinite programming. Finally, we discuss the upper bounds that are obtained from these different methods. / Tsirelson's gräns är den övre gränsen till en Bell olikhet som är giltig för alla kvantmekaniska system. Vi diskuterar varför Tsirelson's gräns togs fram genom att titta på histroiska argument i kvantfysik, så som Einstein-Podolsky-Rosen (EPR) paradoxen, ett argument som säger att den kvantmekaniska beskrivningen av den fysikaliska verkligheten är offulständig, och lokala gömda variabler. Vi presenterar motargumentet till dessa teorier, Bell's olikheter, som senare generaliserades för att betyda alla olikheter som lokala system uppfyller, men som ett system i kvantsammanflättning kan bryta. Vi presenterar beviset för två specifika Bell olikheter: CHSH olikheten och I3322 olikheten. Sedan bevisas Tsirelson's gräns för CHSH olikheten med ett enkelt system av två sammanflättade spin-1/2 partiklar och ett generellt argument som stämmer för alla sammanflättade system. Vi ger den övre kvant gränsen för den generaliserade Clauser-Horne-Shimony-Holt (CHSH) olikheten, som beskriver situationen då vi har flera valmöjligheter för mätningar, genom att använda semidefinit programmering. Vi bevisar Tsirelson's gräns för I3322 olikheten genom att använda maximalt sammanflättade system och semidefinit programmering. Till slut diskuterar vi de övre gränserna som har erhållits ifrån de olika metoderna.

The purpose of the present thesis is to study the influence of Proton Exchange on Electric Field assisted Poling of congruent Lithium Niobate and its applications on periodically pat-terned structures. Moreover, the possibility of using Proton Exchange to avoid neighbours domains merging is studied and successfully demonstrated for period shorter than 10μm. Before approaching the poling of periodically patterned LiNbO3 samples, the main charac-teristics of the evolution of the poling of uniform samples in different masking conditions are investigated. It is well known that the kinetics of domains switching is highly dependent on the poling setup and on the quality/type of electrode employed to contact the crystal to the high voltage. We used a thin layer of Titanium both as mask for proton diffusion and as metal electrode for poling experiments. Moreover different masking configurations are pre-sented and characterized. The second part of this work deals with the periodic poling of 0.5mm-thick congruent lith-ium niobate. 9x4 mm2 1-D Ti gratings with 8.66μm and 8.03μm period were first fabricated on the +z side of the crystal and a superficial chemical pattern was reproduced via acid bath. Three different types of samples were obtained and before the poling the metallic mask was removed whereas in one configuration it was left assuring better homogeneity of the in-verted areas. The results we obtained suggest it could be possible to achieve periodically poled congruent lithium niobate gratings with period shorter than 4μm in ~500μm thick samples and hence obtain aspect ratios of more than 250.

The aim of the study was to investigate if PRIMA-1, a drug that reactivate the tumour suppressor gene p53, will have a synergistic effect when used in combination with γ-irradiation in a human small cell lung cancer cell line (U-1690), which show a low-dose hypersensitivity in clonogenic survival experiments. Clonogenic cell survival after incubation with PRIMA-1 alone in concentrations from 0.1 to 30 µM or in combination with γ-irradiation with a 137Cs source was performed. The standard LQ model, and the repairable-conditionally repairable damage model, the RCR model, were fitted to the experimental data. PRIMA-1 showed a time and concentration dependent cytotoxic, and 10 µM killed 60 % of cells during 72 hours incubation. The cells show low-dose hypersensitivity calculated with the RCR model. The combined treatment with 8 µM PRIMA-1 had a synergistic effect with irradiation doses from 2 Gy and above. The overall conclusion is that a combination with PRIMA-1 and irradiation is beneficial to achieve the best effect.

Det är skolans uppgift att utveckla och stimulera både det vardagliga- och vetenskapliga tänkandet hos elever. Utifrån konstruktivismen ska lärande anpassas till det stadium som elever befinner sig i, för att de ska ha möjlighet att konstruera föreställningar och förståelse av omvärlden. Att som lärare ha förståelse för de föreställningar elever har är därav viktigt för att förbättra undervisningen. Syftet med studien är att undersöka samt analysera elevers föreställningar om vad elektricitet är och hur de förklarar fenomenet, i jämförelse med hur läromedel anpassade för eleverna förklarar fenomenet. För att besvara frågeställningarna genomfördes semistrukturerade gruppintervjuer med 12 elever i fem grupper för att ta reda på deras föreställningar. Det genomfördes även en innehållsanalys av två läromedel för att ta reda på vilka begrepp de använder för att beskriva elektricitet. Resultatet visar att eleverna har skilda föreställningar om vad elektricitet är och att de använder många av de mest frekventa begreppen från läromedlen. Dessa begrepp är: batteri, elektricitet, elektron, lampa, sladd samt ström. Av dessa begrepp är det elektron som används i mindre utsträckning hos eleverna.

A small report on modelling an electrolyte flow-battery using the software COMSOL.

Structure determination of proteins is vital for the understanding of their function. It often relies on techniques that use intense X-ray pulses to create diffraction patterns of protein crystals, which then contain information on the three-dimensional structure of the crystallised protein. An emerging technique called Single Particle Imaging (SPI) aims to make possible the structure determination without the need for crystallisation of the proteins, by taking diffraction patterns from many individual proteins. Translating the diffraction patterns to spatial geometry is a daunting task that requires sophisticated algorithms which are not always able to determine the structure because of fundamental uncertainties in the recovery process. To improve the structure determination process, one can try to rotate the protein to a known orientation using electric fields before the measurement takes place. However, as a result of how these experiments are performed, the proteins may have water around them during this orientation phase. Using molecular dynamics (MD) on ubiquitin, a small protein found in all eukaryotic cells, it is shown that a layer of water around a protein does not only help to achieve orientation faster (compared to an identical protein without this layer), the water also provides the protein with increased structural stability.

Recently, there has been an increase in the number of proton beam therapy (PBT) centers operating worldwide. For certain cases, proton beams have been shown to provide dosimetric and radiobiological advantages when used for cancer treatment, compared to the regular photon-beam based treatments. Under ideal circumstances, the dose given to the tissues surrounding a target can be reduced with PBT. The risk for side effects following treatment is then expected to decrease. Until present, mainly stationary targets, e.g. targets in the brain, have been treated with PBT. There is currently a growing interest to treat also target volumes in other parts of the body with PBT. However, there are sources of uncertainties, which must be more carefully considered when PBT is used, especially for PBT carried out with scanned proton beams. PBT is more sensitive to anatomical changes, e.g. organ motion or a variable gas content in the intestines, which requires that special precautions are taken prior to treating new tumour sites. In photon beam radiotherapy (RT) of moving targets, the main consequence of organ motion is the loss of sharpness of the dose gradients (dose smearing). When scanned proton beams are used, dose deformation caused by the fluctuations in the proton beam range, due to varying tissue heterogeneities (e.g., the ribs moving in and out of the beam path) and the so-called interplay effect, can be expected to impact the dose distributions in addition to the dose smearing. The dosimetric uncertainties, if not accounted for, may cause the planned and accurately calculated dose distribution to be distorted, compromising the main goal of RT of achieving the maximal local disease control while accepting certain risks for normal tissue complications. Currently there is a lack of clinical follow-up data regarding the outcome of PBT for different tumour sites, in particular for extra-cranial tumour sites in moving organs. On the other hand, the use of photon beams for this kind of cancer treatment is well-stablished. A treatment planning comparison between RT carried out with photons and with protons may provide guidelines for when PBT could be more suitable. New clinical applications of particle beams in cancer therapy can also be transferred from photon-beam treatments, for which there is a vast clinical experience. The evaluation of the different uncertainties influencing RT of different tumour sites carried out with photon- and with proton-beams, will hopefully create an understanding for the feasibility of treating cancers with scanned proton beams instead of photon beams. The comparison of two distinct RT modalities is normally performed by studying the dosimetric values obtained from the dose volume histograms (DVH). However, in dosimetric evaluations, the outcome of the treatments in terms of local disease control and healthy tissue toxicity are not estimated. In this regard, radiobiological models can be an indispensable tool for the prediction of the outcome of cancer treatments performed with different types of ionising radiation. In this thesis, different factors that should be taken into consideration in PBT, for treatments influenced by organ motion and density heterogeneities, were studied and their importance quantified. This thesis consists of three published articles (Articles I, II and III). In these reports, the dosimetric and biological evaluations of photon-beam and scanned proton-beam RT were performed and the results obtained were compared. The studies were made for two tumour sites influenced by organ motion and density changes, gastric cancer (GC) and liver metastases. For the GC cases, the impact of changes in tissue density, resulting from variable gas content (which can be observed inter-fractionally), was also studied. In this thesis, both conventional fractionations (implemented in the planning for GC treatments) and hypofractionated regimens (implemented in the planning for the liver metastases cases) were considered. In this work, it was found that proton therapy provided the possibility to reduce the irradiations of the normal tissue located near the target volumes, compared to photon beam RT. However, the effects of density changes were found to be more pronounced in the plans for PBT. Furthermore, with proton beams, the reduction of the integral dose given to the OARs resulted in reduced risks of treatment-induced secondary malignancies.