Filetype
In this thesis, I present both theoretical and empirical work where we have studied how humans and animals use information in situations where they need to continually update their information on the density of a resource. We have found that the amount of information, and the way the information is presented, are important factors for how well decisions are adapted to current circumstances. In an
The intention of this work was to establish alternative purification methods to obtain highly purified caveolae from various tissues. In order to isolate caveolae, sufficiently pure plasma membranes are needed. A method is presented for the isolation of plasma membranes from lung tissue using a combination of conventional polyethylene glycol/dextran two-phase partitioning and affinity partitioning
In this thesis, electron transport in mesoscopic semiconductor nanostructures, in particular so-called electron billiards or quantum dots, is studied. The thesis can be divided into two areas: the linear response regime of transport, and the nonlinear response regime of transport. The classical and quantum mechanical electron dynamics are studied for triangular and square-shaped electron billiard
Movement and dispersal are important determinants of the spatial distribution and persistence of animal populations in a heterogeneous environment. I studied the small-scale movement pattern of a soil-living insect, Protaphorura armata (Collembola) by using a video-equipment. I added chemical cues, food and conspecifics to their environment and evaluated the effects of external cues on the movemen
Elastic scattering and the Lorenz-Mie (LM) theory in particular is used for the characterization of sub-micron- and micron-sized droplets of organic fuels in sprays and aerosols. Calculations on the Lorenz- Mie theory show that backward-sideward scattered visible radiation can be used for unambiguous detection of ensembles of homogeneous droplets of organic substances with diameters around 1 micro
The legislative limits for NOX emissions in the exhaust gas from heavy-duty diesel engines will be decreased in the European Union from today 3.5 g/kWh (Euro IV) to 2.0 g/kWh in 2008 (Euro V). In the USA and Japan a similar trend can be seen. Accordingly, the development of an exhaust aftertreatment system for heavy-duty trucks seems unavoidable. In this work, an 11 l diesel engine rig has been bu
The fermentative performance of bacteria, yeasts, and filamentous fungi was investigated in a pentose (xylose)-rich lignocellulosic hydrolyzate. The filamentous fungus Fusarium oxysporum and the xylose-fermenting yeast Pichia stipitis were found to be very sensitive to the inhibiting hydrolyzate. Recombinant xylose-utilizing Saccharomyces cerevisiae showed very poor ethanol formation from xylose;
In fantasy literature, the setting is as important to the story as are characters and plot; but although many fantasy scholars have pointed this out, there is very little criticism that explores the role of the setting in fantasy. The aim of this study is to use a topofocal (place-focused) perspective to examine four aspects of the fantasy setting, including the way in which settings function in t
During tumor progression a strong immunosuppression is developed and is believed to be the major reason why immunotherapy fails. This suppression is induced in response to factors produced from tumor cells, but can also be induced after immunotherapy. NO has been shown to play a major role in this suppression both in patients with gliomas and colon carcinomas. The aim of this thesis is to clarify
To measure the importance of early neurodevelopmental disturbance for schizophrenia, early trauma and dysmorphogenesis (i.e. obstetric complications (OCs), minor physical anomalies (MPAs), head circumference (HC) and dermatoglyphic characteristics) were studied in relationship to adult neurodysfunction (i.e. neurological abnormality (NA), neurocognitive dysfunction (NCGD), tardive dyskinesia (TD)
Microorganisms in forest ecosystems normally recycle nitrogen (N), such that gaseous losses and leaching are limited. Mobilization of organic N, including microbial N, and immobilization of inorganic N, especially NH4+, are the quantitatively most important N transformation processes. Various factors influence their rates, e.g. the amount of carbon and nitrogen, temperature, moisture, and the micr
The biosynthesis of chlorophylls is an important process in nature. The green pigments play a fundamental role in absorbing and transferring solar energy to the photosynthetic apparatus. This thesis elucidates the role and function of the enzyme magnesium chelatase, which catalyses the insertion of magnesium (II) into protoporphyrin IX and is the first committed enzyme of the chlorophyll biosynthe
There are many examples of complex networks in science. It can be genetic regulation in living cells, computers on the Internet, or social and economic networks. In this context, Boolean networks provide simplistic models that are relatively easy to handle using computer simulations and mathematical methods. A good understanding of Boolean networks may form a foundation to investigations of more c
Epilepsy is a syndrome characterized by recurring attacks of sudden, excessive and synchronous discharge in populations of cerebral neurons. Kindling is an animal model for complex partial epilepsy, and is particularly useful for studies on the development of the abnormal excitability underlying the generation and spread of epileptic seizures. Here we have used the kindling model to investigate me
A comparison of essential oils from leaves of Eucalyptus camaldulensis Dehn. obtained by hydrodistillation (HD) and supercritical carbon dioxide (SC-CO2) extraction is presented. Selected major components of the oils showed a predominance of higher molecular weight components in the SC-CO2 extracts than in those obtained by HD. Physico chemical properties such as molecular weight, vapour pressure
The aim of the thesis is to contribute to knowledge of (1) psychosocial illness in the population, (2) the prevalence and nature of psychosocial illness encountered in primary health care, and (3) encountered among persons with long-term illness. The data collected include the results of a questionnaire given to a population-based sample of 13 000 persons (20-84 years), a questionnaire given to ge
The serotonergic vascular control was investigated by in vitro pharmacology in the human uterine and umbilical arteries. The localisation of immunoreactive (IR) neuropeptide Y (NPY) and the influence of NPY on the adrenergic vascular effects in the human uterine artery were also studied. NPY-IR nerve fibres were observed predominantly at the media-adventitial border of the uterine artery. About 50
This thesis concerns clean and adsorbate covered metal surfaces and surface alloys. These systems have been studied using theoretical and experimental methods. In the first part of the thesis, the different techniques that have been utilized in this work are presented, and the included publications are summarized. The second part of the thesis consists of seven original publications. In the first
Modern communication systems strive to achieve reliable and efficient information transmission and storage with affordable complexity. Hence, efficient low-complexity channel codes providing low probabilities for erroneous receptions are needed. Interpreting codes as graphs and graphs as codes opens new perspectives for constructing such channel codes. Low-density parity-check (LDPC) codes are one
