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Generation of Ultrashort Pulses – From Femtoseconds to Attoseconds

Electronic dynamics takes place on the attosecond timescale and can thus only be studied using a tool with attosecond temporal resolution. High harmonic generation (HHG) provides coherent attosecond pulses in the extreme ultraviolet spectral region. The work presented in this thesis focuses on generating and characterizing ultrashort femtosecond pulses and using them for HHG, together with a gatin

The ins and outs of SMIM1 and its relationship to the expression of Vel blood group antigen

Background: Vel blood group expression is dependent on Small Integral Membrane Protein 1 (SMIM1), a recently discovered erythroid protein. SMIM1 consists of 78 amino acids (aa) and shows only limited homology to other human proteins but is evolutionarily conserved, indicating its importance. The protein has a predicted transmembrane domain but the direction of insertion into the red blood cell (RB

Adsorption, desorption, and redox reactions at iron oxide nanoparticle surfaces

Soils play a critical role in the carbon (C) cycle by regulating the atmospheric carbon dioxide (CO2) levels, and correspondingly the Earth’s climate. However, there are still countless questions of how biological and geochemical soil processes affect the C cycle. To be able to predict future implications on the Earth’s climate, we need to understand these processes. Globally, soils store more C tIron oxide nanoparticles are involved in several important biogeochemical processes. The interfaces between aqueous solutions and iron oxide nanoparticle surfaces are found everywhere in nature, and the chemical and microbial processes occurring at these complex interfaces control e.g. nutrient and contaminant availability and transport. Recently, it has been shown that certain ectomycorrhizal (EC

Observations on Cooperation

We study environments in which agents are randomly matched to play a Prisoner’s Dilemma, and each player observes a few of the partner’s past actions against previous opponents. We depart from the existing related literature by allowing a small fraction of the population to be commitment types. The presence of committed agents destabilizes previously proposed mechanisms for sustaining cooperation.

Efficient Adaptive MCMC Through Precision Estimation

The performance of Markov chain Monte Carlo (MCMC) algorithms like the Metropolis Hastings Random Walk (MHRW) is highly dependent on the choice of scaling matrix for the proposal distributions. A popular choice of scaling matrix in adaptive MCMC methods is to use the empirical covariance matrix (ECM) of previous samples. However, this choice is problematic if the dimension of the target distributi

Latent Gaussian random field mixture models

For many problems in geostatistics, land cover classification, and brain imaging the classical Gaussian process models are unsuitable due to sudden, discontinuous, changes in the data. To handle data of this type, we introduce a new model class that combines discrete Markov random fields (MRFs) with Gaussian Markov random fields. The model is defined as a mixture of several, possibly multivariate,

Level set Cox processes

The log-Gaussian Cox process (LGCP) is a popular point process for modeling noninteracting spatial point patterns. This paper extends the LGCP model to handle data exhibiting fundamentally different behaviors in different subregions of the spatial domain. The aim of the analyst might be either to identify and classify these regions, to perform kriging, or to derive some properties of the parameter

Nya perspektiv på genomströmning i nätbaserade utbildningar

Enligt HSVs rapport ”Kartläggning av distansverksamheten vid universitet ochhögskolor” från 2011 är genomströmningen i landets distansutbildningar betydligt lägre än motsvarande för campusutbildningar. I detta paper kommer jag att belysa fenomenet genomströmning genom att rikta blicken mot MOOCs, en annan typ av nätbaserade kurser än de som vanligtvis diskuteras i sammanhanget. MOOCs erbjuder en m

Developing a method for driving the solar control mechanism selection

A method was developed, which drives the selection of appropriate solar control mechanisms based on theanalysis of overheating due to solar heat gains. The aim of the method is to maintain adequate thermalcomfort levels in highly glazed spaces. Two thermal comfort models, Predicted Mean Vote and AdaptiveModel, were chosen to set the thermal comfort boundaries included in the method. Moreover, in o

Modeling of a solar dryer for fruit preservation in developing countries

About 25,3 % of the Mozambican population is suffering from undernourishment even though a sufficient amount of food and specifically fruits are produced. Post-harvest losses are estimated to 25 % to 40 % and part of the production is not even harvested due to a short season. A solution has to be found to improve fruit preservation and allow the population to consume what is harvested later. Dryin