Cutaneous reparative processes, including wound healing, are highly developed procedures in which a chain of actions occurs to reconstitute the function of the wounded tissue. To prevent a delayed or excessive reparative process it is important to understand how this procedure develops and is maintained. One of the major extracellular matrix components of the skin is the glycosaminoglycan hyaluronan (HA). HA contributes to an extracellular environment, which is permissive for cell motility and proliferation, features that may account for HA’s unique properties observed in scarless foetal wound healing. The molecule is found at high concentration whenever proliferation, regeneration and repair of tissue occur. The aims of the present studies were to analyse the distribution of HA and to investigate its possible role in various cutaneous conditions associated with an impaired reparative process like in scar tissue formation in healing wounds, changed skin characteristics in diabetes mellitus and proliferating activity in basal cell carcinomas. Tissue biopsies were obtained from healthy human skin, type-I diabetic skin and various scar tissues. The samples were analysed in the light microscope with a hyaluronan-binding-probe, antibodies for collagen I, III, PCNA and Ki-67. Ultrastructural analyses were performed on the same tissue samples. In normal skin HA was present mainly in the papillary dermis. In epidermis HA was located in between the keratinocytes in the spinous layer. In the different scar tissues the localization of HA varied, with an HA distribution in mature scar type resembling that in normal skin. In keloids the papillary dermis lacked HA, but the thickened epidermis contained more HA than the other scar types. Ultrastructural studies of keloids revealed an altered collagen structure in the dermal layers, with an abundance of thin collagen fibers in the reticular dermis and thicker collagen fibers in the papillary dermis. Furthermore, the keloids displayed epidermal changes, which involved the basement membrane (BM), exhibiting fewer hemidesmosomes, and an altered shape of desmosomes in the entire enlarged spinous layer. These alterations in epidermis are suggested to influence the hydrodynamic and cell regulatory properties of the wounded skin. In diabetic patients, a reduced HA staining in the basement membrane zone was seen. The staining intensity of HA correlated to the physical properties of the skin reflected by their grades of limited joint mobility (LJM). Furthermore, the HA staining correlated with serum concentration of the HbA1c. In basal cell carcinomas (BCC), HA occurred predominantly in the tumour stroma. The distribution was most intense in the highly developed superficial BCC type, and resembled that of the papillary dermis of normal skin. In contrast, in the infiltrative BCC type, the tumour stroma stained weakly in the infiltrative part of the tumour. Moreover, the surrounding dermal layer was deranged and devoid of HA. The findings suggest that the tumour stroma in superficial BCC causes a slow, well-regulated cell growth in which the tumour cells do not substantially disturb the normal skin function. In the infiltrative BCC type, the tumour cells cause a disintegration of the tumour stroma as well as the normal surrounding dermis, which permits further spreading of the tumour. In fact, the behaviour of the infiltrative BCC tumour, growing beyond its boundaries, resembles that of the keloid. The mapping of the distribution of HA could be a useful tool for prognostic information, for evaluating the degree of progress and for deciding the choice of treatment in various diseases of the skin. In skin malignancies such as BCC it can be used to determine the radicality at the surgical excision of the tumour. Keywords: Hyaluronan, scar tissue, diabetes mellitus, basal cell carcinoma, skin, wound healing

Feature binding refers to the fundamental challenge of the brain to integrate sensory information registered by distinct brain regions to form a unified neural representation of a stimulus. While the human cognitive literature has established that attentional processes in a frontoparietal cortical network support feature binding, the neurochemical contributions to this attentional process remain unknown. Using systemic administration of the cholinergic muscarinic receptor antagonist scopolamine and a digging-based rat feature binding task that used both odor and texture stimuli, it was demonstrated that blockade of acetylcholine (ACh) at the muscarinic receptors impaired rats’ ability to feature bind at encoding, and it was proposed that ACh may support the attentional processes necessary for feature binding (Botly & De Rosa, 2007). This series of experiments further investigated a role for ACh and the cholinergic basal forebrain (BF) in feature binding. In Experiment 1, a cross-species experimental design was employed in which rats under the systemic influence of scopolamine and human participants under divided-attention performed comparable feature binding tasks using odor stimuli for rats and coloured-shape visual stimuli for humans. Given the comparable performance impairments demonstrated by both species, Experiment 1 suggested that ACh acting at muscarinic receptors supports the attentional processes necessary for feature binding at encoding. Experiments 2-4 investigated the functional neuroanatomy of feature binding using bilateral quisqualic acid excitotoxic (Experiment 2) and 192 IgG-saporin cholinergic immunotoxic (Experiments 3 and 4) brain lesions that were assessed for completeness using histological and immunohistological analyses. Using the crossmodal digging-based rat feature binding task, Experiment 2 revealed that the nucleus basalis magnocellularis (NBM) of the BF is critically involved in feature binding, and Experiment 3 revealed that cholinergic neurons in the NBM are necessary for feature binding at encoding. Lastly, in Experiment 4, rats performed visual search, the standard test of feature binding in humans, with touchscreen-equipped operant chambers. Here it was also revealed that cholinergic neurons in the NBM of the BF are critical for efficient visual search. Taken together, these behavioural, pharmacological, and brain-lesion findings have provided insights into the neurochemical contributions to the fundamental attentional process of feature binding.

Meltwater reaching the base of the snowpack may either infiltrate the underlying stratum, run off, or refreeze, forming a basal ice layer. Frozen ground underneath a melting snowpack constrains infiltration promoting runoff and refreezing. Compositional changes in chemistry take place for each of these flowpaths as a result of phase change, contact between meltwater and soil, and mixing between meltwater and soil water. Meltwater ion concentrations and infiltration rate into frozen soils both decline rapidly as snowmelt progresses. Their temporal association is highly non-linear and the covariance must be compensated for in order to use time-averaged values to calculate chemical infiltration over a melt event. This temporal covariance is termed �enhanced infiltration� and represents the additional ion load that infiltrates due to the timing of high meltwater ion concentration and infiltration rate. Both theoretical and experimental assessments of the impact of enhanced infiltration showed that it causes a greater ion load to infiltrate leading to relative dilute runoff water. Sensitivity analysis showed that the magnitude of enhanced infiltration is governed by initial snow water equivalent, average melt rate, and meltwater ion concentration factor. Based on alterations in water chemistry due to various effects, including enhanced infiltration, three major flowpaths could be distinguished: overland flow, organic interflow, and mineral interflow. Laboratory experiments were carried out in a temperature-controlled environment to identify compositional changes in water from these flowpaths. Samples of meltwater, runoff, and interflow were filtered and analyzed for major anions and cations. Chemical signatures for each flowpath were determined by normalizing runoff and interflow concentrations using meltwater concentrations. Results showed that changes in ion concentrations were most significant for H⁺, NO₃^�, NH₄⁺, Mg²⁺, and Ca²⁺. Repeated flushes of meltwater through each interflowpath caused a washout of ions. In the field, samples of soil water and ponding water were collected daily from a Rocky Mountain hillslope during snowmelt. Their normalized chemical compositions were compared to the laboratory-identified signatures to evaluate the flowpath. The majority of the flowpaths sampled had chemical signatures, which indicated mineral interflow, only 10% showed unmixed organic interflow.

This dissertation is about reading instruction in six mixed-aged classes, called child schools, with six and seven year old children. The overall questions of this study were: How did the teachers in child schools organise work in general and reading instruction in particular? How did they handle for example the increasing range of variation concerning knowledge and skills that goes together with increasing variation of age? With respect to reading the investigation also examined the content of reading instruction and the extent to which teachers took into account those factors that, according to reading research, are important for the acquisition of reading skills? Overall the research aimed to examine how the reading ability of the pupils developed during their first years at school. Six child schools were included in the study. The data collection extended over three years and contained field studies, interviews with the staff and reading tests with the pupils. Reading theories were used to analyse the form of the reading instruction and Basil Bernstein's theory of visible and invisible pedagogy was used to analyse pedagogical practice in its context. With one exception a visible pedagogy dominated in all the child schools. During lessons designated "my own work" the pupils were allowed to plan their work. This weak framing allowed the pupils to sort themselves into groups of more or less successful learners. In reading instruction, elements of two different models for instruction were combined, e.g. the whole language and the basal reading approach. My conclusion is that this combination is effective in a mixed-age group. Pupils at different competence levels benefit from different approaches. The reading comprehension of the child school pupils did not differ from the levels obtained with comparable pupils in national surveys. The test results, like the learning conditions varied between the schools. In my view the test results were not merely a consequence of the instruction, but also of other circumstances that interacted with the pedagogy.

Feature binding refers to the fundamental challenge of the brain to integrate sensory information registered by distinct brain regions to form a unified neural representation of a stimulus. While the human cognitive literature has established that attentional processes in a frontoparietal cortical network support feature binding, the neurochemical contributions to this attentional process remain unknown. Using systemic administration of the cholinergic muscarinic receptor antagonist scopolamine and a digging-based rat feature binding task that used both odor and texture stimuli, it was demonstrated that blockade of acetylcholine (ACh) at the muscarinic receptors impaired rats’ ability to feature bind at encoding, and it was proposed that ACh may support the attentional processes necessary for feature binding (Botly & De Rosa, 2007). This series of experiments further investigated a role for ACh and the cholinergic basal forebrain (BF) in feature binding. In Experiment 1, a cross-species experimental design was employed in which rats under the systemic influence of scopolamine and human participants under divided-attention performed comparable feature binding tasks using odor stimuli for rats and coloured-shape visual stimuli for humans. Given the comparable performance impairments demonstrated by both species, Experiment 1 suggested that ACh acting at muscarinic receptors supports the attentional processes necessary for feature binding at encoding. Experiments 2-4 investigated the functional neuroanatomy of feature binding using bilateral quisqualic acid excitotoxic (Experiment 2) and 192 IgG-saporin cholinergic immunotoxic (Experiments 3 and 4) brain lesions that were assessed for completeness using histological and immunohistological analyses. Using the crossmodal digging-based rat feature binding task, Experiment 2 revealed that the nucleus basalis magnocellularis (NBM) of the BF is critically involved in feature binding, and Experiment 3 revealed that cholinergic neurons in the NBM are necessary for feature binding at encoding. Lastly, in Experiment 4, rats performed visual search, the standard test of feature binding in humans, with touchscreen-equipped operant chambers. Here it was also revealed that cholinergic neurons in the NBM of the BF are critical for efficient visual search. Taken together, these behavioural, pharmacological, and brain-lesion findings have provided insights into the neurochemical contributions to the fundamental attentional process of feature binding.

‘Animal personality’ refers to individual behavioural differences that are consistent over time and context. Physiological constraints are suggested to underlie this constraint in behavioural plasticity. As energy is required for physiological processes that generate behaviour, energy metabolism could be a proximate explanation for personality. Currently, the most coherent framework linking behaviour, metabolism and life history-traits is still poorly tested empirically, and studies are showing contradicting results. Therefore, I here aim to explore this relationship further by investigating the relationship between basal metabolic rate (BMR) and personality in Red Junglefowl (Gallus gallus). Birds used had known responses in personality assays, and their metabolic rates were measured by determining oxygen consumption in standardized conditions throughout the night using an open respirometry system. BMR was negatively correlated with time spent foraging, and positively correlated with time spent being vigilant. Considering foraging an ‘activity’ (due to its energy-demand), my results support the allocation model, a model that assumes that an animal has a fixed amount of energy, thus that an energetic trade-off occur between competing energy requiring processes such as BMR and activity. Hence, an animal with low BMR has more energy to spend on activity. However, I do not consider vigilance as an energy-demanding activity; hence this relationship cannot be interpreted in this framework. Taken together, my results show a relationship between personality and BMR, although their relationship still needs further investigation to understand the causality and consequences of it.

A two dimensional continuous numerical model based on Discrete Element Method is used to investigate the behaviour of accretionary wedges with different basal frictions. The models are based on elastic-plastic, brittle material and computational granular dynamics, and several characteristics of the influence of the basal friction are analysed. The model results illustrate that the wedge’s deformation and geometry, for example, fracture geometry, the compression force, area loss, displacement, height and length of the accretionary wedge etc., are strongly influenced by the basal friction. In general, the resulting wedge grows steeper, shorter  and higher, and the compression force is larger when shortened  above a larger friction basement.  Especially, when there is no basal friction, several symmetrical wedges will distribute symmetrically in the domain. The distribution of the internal stress when a new accretionary prime is forming is also studied. The results illustrate that when the stress in a certain zone is larger than a critical number, a new thrust will form there.

No description available.

Meltwater reaching the base of the snowpack may either infiltrate the underlying stratum, run off, or refreeze, forming a basal ice layer. Frozen ground underneath a melting snowpack constrains infiltration promoting runoff and refreezing. Compositional changes in chemistry take place for each of these flowpaths as a result of phase change, contact between meltwater and soil, and mixing between meltwater and soil water. Meltwater ion concentrations and infiltration rate into frozen soils both decline rapidly as snowmelt progresses. Their temporal association is highly non-linear and the covariance must be compensated for in order to use time-averaged values to calculate chemical infiltration over a melt event. This temporal covariance is termed �enhanced infiltration� and represents the additional ion load that infiltrates due to the timing of high meltwater ion concentration and infiltration rate. Both theoretical and experimental assessments of the impact of enhanced infiltration showed that it causes a greater ion load to infiltrate leading to relative dilute runoff water. Sensitivity analysis showed that the magnitude of enhanced infiltration is governed by initial snow water equivalent, average melt rate, and meltwater ion concentration factor. Based on alterations in water chemistry due to various effects, including enhanced infiltration, three major flowpaths could be distinguished: overland flow, organic interflow, and mineral interflow. Laboratory experiments were carried out in a temperature-controlled environment to identify compositional changes in water from these flowpaths. Samples of meltwater, runoff, and interflow were filtered and analyzed for major anions and cations. Chemical signatures for each flowpath were determined by normalizing runoff and interflow concentrations using meltwater concentrations. Results showed that changes in ion concentrations were most significant for H⁺, NO₃^�, NH₄⁺, Mg²⁺, and Ca²⁺. Repeated flushes of meltwater through each interflowpath caused a washout of ions. In the field, samples of soil water and ponding water were collected daily from a Rocky Mountain hillslope during snowmelt. Their normalized chemical compositions were compared to the laboratory-identified signatures to evaluate the flowpath. The majority of the flowpaths sampled had chemical signatures, which indicated mineral interflow, only 10% showed unmixed organic interflow.

In this thesis, the learning of probabilistic relationships between stimulus-action pairs is investigated under the probability learning paradigm. The effect of reward is investigated in the first three experiments. Additionally, the effect of context and uncertainty is investigated in the second and third experiments, respectively. The fourth experiment is the replication of the second experiment with a group of Parkinson patients where the effect of dopamine medication on probability learning is studied. In Experiment 1, we replicate the classical probability learning task by comparing monetary and non-monetary reward feedback. Probability learning behavior is observed in both monetary and non-monetary rewarding feedback conditions. However, no significant difference between the monetary and non-monetary feedback conditions is observed. In Experiment 2, a variation of the probability learning task which includes irrelevant contextual information is applied. Probability learning behavior is observed, and a significant effect is found between monetary and non-monetary feedback conditions. In Experiment 3 / a probability learning task similar to that in Experiment 2 is applied, however, in this experiment, stimulus included relevant contextual information. As expected, due to the utilization of the relevant contextual information from the start of the experiment, no significant effect is found for probability learning behavior. The effect of uncertainty observed in this experiment is a replication of the reports in literature. Experiment 4 is identical to Experiment 2 / except that the subject population is a group of dopamine medicated Parkinson patients and a group of age matched controls. This experiment is introduced to test the suggestions in the literature regarding the enhancement effect of dopamine medication in probability learning based on positive feedback conditions. In Experiment 4, probability learning behavior is observed in both groups, but the difference in learning performance between Parkinson patients and controls was not significant, probably due to the low number of subject recruited in the experiment. In addition to these investigations, learning mechanisms are also examined in Experiments 1 and 4. Our results indicate that subjects initially search for patterns which lead to probability learning. At the end of Experiments 1 and 4, upon learning the winning frequencies, subjects change their behavior and demonstrate maximization behavior, which makes them prefer continuously one option over the other.