26 resultados para DETERMINES

em Helda - Digital Repository of University of Helsinki


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This paper analyzes factors driving the design of stock option plans for Finnish firms. We examine determinants of the scope of plans, exercise price, target group, and dividend protection. The scope is found to be negatively related to Tobin’s Q and positively related to proxies for monitoring costs. The scope is also greater in broad-based plans, and in plans with dividend protection. Prior stock return is found to be negatively related to the size of the premium (out-of-the-moneyness), whereas dividend protection increases the premium. The results also suggest that investment intensity, cash flow, and monitoring costs are associated with the likelihood of granting premium (out-of-the-money) stock options. Furthermore, the likelihood of granting broad-based plans is increasing in institutional ownership and cash flow constraints, and decreasing in firm size. Broad-based plans are also more likely among firms in growth industries. We find support that the likelihood of dividend protection is decreasing in foreign ownership. In addition, firms paying zero-dividends are less likely to include dividend protection, whereas higher unsystematic risk is associated with a greater likelihood of including dividend protection.

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This study examines both theoretically an empirically how well the theories of Norman Holland, David Bleich, Wolfgang Iser and Stanley Fish can explain readers' interpretations of literary texts. The theoretical analysis concentrates on their views on language from the point of view of Wittgenstein's Philosophical Investigations. This analysis shows that many of the assumptions related to language in these theories are problematic. The empirical data show that readers often form very similar interpretations. Thus the study challenges the common assumption that literary interpretations tend to be idiosyncratic. The empirical data consists of freely worded written answers to questions on three short stories. The interpretations were made by 27 Finnish university students. Some of the questions addressed issues that were discussed in large parts of the texts, some referred to issues that were mentioned only in passing or implied. The short stories were "The Witch à la Mode" by D. H. Lawrence, "Rain in the Heart" by Peter Taylor and "The Hitchhiking Game" by Milan Kundera. According to Fish, readers create both the formal features of a text and their interpretation of it according to an interpretive strategy. People who agree form an interpretive community. However, a typical answer usually contains ideas repeated by several readers as well as observations not mentioned by anyone else. Therefore it is very difficult to determine which readers belong to the same interpretive community. Moreover, readers with opposing opinions often seem to pay attention to the same textual features and even acknowledge the possibility of an opposing interpretation; therefore they do not seem to create the formal features of the text in different ways. Iser suggests that an interpretation emerges from the interaction between the text and the reader when the reader determines the implications of the text and in this way fills the "gaps" in the text. Iser believes that the text guides the reader, but as he also believes that meaning is on a level beyond words, he cannot explain how the text directs the reader. The similarity in the interpretations and the fact that the agreement is strongest when related to issues that are discussed broadly in the text do, however, support his assumption that readers are guided by the text. In Bleich's view, all interpretations have personal motives and each person has an idiosyncratic language system. The situation where a person learns a word determines the most important meaning it has for that person. In order to uncover the personal etymologies of words, Bleich asks his readers to associate freely on the basis of a text and note down all the personal memories and feelings that the reading experience evokes. Bleich's theory of the idiosyncratic language system seems to rely on a misconceived notion of the role that ostensive definitions have in language use. The readers' responses show that spontaneous associations to personal life seem to colour the readers' interpretations, but such instances are rather rare. According to Holland, an interpretation reflects the reader's identity theme. Language use is regulated by shared rules, but everyone follows the rules in his or her own way. Words mean different things to different people. The problem with this view is that if there is any basis for language use, it seems to be the shared way of following linguistic rules. Wittgenstein suggests that our understanding of words is related to the shared ways of using words and our understanding of human behaviour. This view seems to give better grounds for understanding similarity and differences in literary interpretations than the theories of Holland, Bleich, Fish and Iser.

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Le naturalisme finlandais. Une conception entropique du quotidien. Finnish Naturalism. An Entropic Conception of Everyday Life. Nineteenth century naturalism was a strikingly international literary movement. After emerging in France in the 1870s, it spread all over Europe including young, small nations with a relatively recent literary tradition, such as Finland. This thesis surveys the role and influence of French naturalism on the Finnish literature of the 1880s and 1890s. On the basis of a selection of works of six Finnish authors (Juhani Aho, Minna Canth, Kauppis-Heikki, Teuvo Pakkala, Ina Lange and Karl August Tavaststjerna), the study establishes a view of the main features of Finnish naturalism in comparison with that of French authors, such as Zola, Maupassant and Flaubert. The study s methodological framework is genre theory: even though naturalist writers insisted on a transparent description of reality, naturalist texts are firmly rooted in general generic categories with definable relations and constants on which European novels impose variations. By means of two key concepts, entropy and everyday life , this thesis establishes the parameters of the naturalist genre. At the heart of the naturalist novel is a movement in the direction of disintegration and confusion, from order to disorder, from illusion to disillusion. This entropic vision is merged into the representation of everyday life, focusing on socially mediocre characters and discovering their miseries in all their banality and daily grayness. By using Mikhail Bakhtin s idea of literary genres as a means of understanding experience, this thesis suggests that everyday life is an ideological core of naturalist literature that determines not only its thematic but also generic distinctions: with relation to other genres, such as to Balzac s realism, naturalism appears primarily to be a banalization of everyday life. In idyllic genres, everyday life can be represented by means of sublimation, but a naturalist novel establishes a distressing, negative everyday life and thus strives to take a critical view of the modern society. Beside the central themes, the study surveys the generic blends in naturalism. The thesis analyzes how the coalition of naturalism and the melodramatic mode in the work of Minna Canth serves naturalisms ambition to discover the unconscious instincts underlying daily realities, and how the symbolic mode in the work of Juhani Aho duplicates the semantic level of the apparently insignificant, everyday naturalist details. The study compares the naturalist novel to the ideological novel (roman à these) and surveys the central dilemma of naturalism, the confrontation between the optimistic belief in social reform and the pessimistic theory of determinism. The thesis proposes that the naturalist novel s contribution to social reform lies in its shock effect. By means of representing the unpleasant truth the entropy of everyday life it aims to scandalize the reader and make him aware of the harsh realities that might apply also to him.

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This study investigated questions related to half-occlusion processing in human stereoscopic vision: (1) How does the depth location of a half-occluding figure affect the depth localization of adjacent monocular objects? (2) Is three-dimensional slant around vertical axis (geometric effect) affected by half-occlusion constraints? and (3) How the half-occlusion constraints and surface formation processes are manifested in stereoscopic capture? Our results showed that the depth localization of binocular objects affects the depth localization of discrete monocular objects. We also showed that the visual system has a preference for a frontoparallel surface interpretation if the half-occlusion configuration allows multiple interpretation alternatives. When the surface formation was constrained by textures, our results showed that a process of rematching spreading determines the resulting perception and that the spreading can be limited by illusory contours that support the presence of binocularly unmatched figures. The unmatched figures could be present, if the inducing figures producing the illusory surface contained binocular image differences that provided cues for quantitative da Vinci stereopsis. These findings provide evidence of the significant role of half-occlusions in stereoscopic processing.

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Distraction in the workplace is increasingly more common in the information age. Several tasks and sources of information compete for a worker's limited cognitive capacities in human-computer interaction (HCI). In some situations even very brief interruptions can have detrimental effects on memory. Nevertheless, in other situations where persons are continuously interrupted, virtually no interruption costs emerge. This dissertation attempts to reveal the mental conditions and causalities differentiating the two outcomes. The explanation, building on the theory of long-term working memory (LTWM; Ericsson and Kintsch, 1995), focuses on the active, skillful aspects of human cognition that enable the storage of task information beyond the temporary and unstable storage provided by short-term working memory (STWM). Its key postulate is called a retrieval structure an abstract, hierarchical knowledge representation built into long-term memory that can be utilized to encode, update, and retrieve products of cognitive processes carried out during skilled task performance. If certain criteria of practice and task processing are met, LTWM allows for the storage of large representations for long time periods, yet these representations can be accessed with the accuracy, reliability, and speed typical of STWM. The main thesis of the dissertation is that the ability to endure interruptions depends on the efficiency in which LTWM can be recruited for maintaing information. An observational study and a field experiment provide ecological evidence for this thesis. Mobile users were found to be able to carry out heavy interleaving and sequencing of tasks while interacting, and they exhibited several intricate time-sharing strategies to orchestrate interruptions in a way sensitive to both external and internal demands. Interruptions are inevitable, because they arise as natural consequences of the top-down and bottom-up control of multitasking. In this process the function of LTWM is to keep some representations ready for reactivation and others in a more passive state to prevent interference. The psychological reality of the main thesis received confirmatory evidence in a series of laboratory experiments. They indicate that after encoding into LTWM, task representations are safeguarded from interruptions, regardless of their intensity, complexity, or pacing. However, when LTWM cannot be deployed, the problems posed by interference in long-term memory and the limited capacity of the STWM surface. A major contribution of the dissertation is the analysis of when users must resort to poorer maintenance strategies, like temporal cues and STWM-based rehearsal. First, one experiment showed that task orientations can be associated with radically different patterns of retrieval cue encodings. Thus the nature of the processing of the interface determines which features will be available as retrieval cues and which must be maintained by other means. In another study it was demonstrated that if the speed of encoding into LTWM, a skill-dependent parameter, is slower than the processing speed allowed for by the task, interruption costs emerge. Contrary to the predictions of competing theories, these costs turned out to involve intrusions in addition to omissions. Finally, it was learned that in rapid visually oriented interaction, perceptual-procedural expectations guide task resumption, and neither STWM nor LTWM are utilized due to the fact that access is too slow. These findings imply a change in thinking about the design of interfaces. Several novel principles of design are presented, basing on the idea of supporting the deployment of LTWM in the main task.

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Education for a Technological Society. Public School Curriculum Construction, 1945-1952. The subject of my research is the significance of technology in the construction process of the public school curriculum during the years 1945-1952. During the period the war reparation and rebuilding placed demands and actions to rationalise and dramatise industry and agriculture. Thereby the ambitions of building a technological country and the reformation of curriculum took place simultaneously. Fordistian terms of reference, of which the principles were mass production, rationalisation and standardisation, a hierarchical division of labour and partition of assignments, provided a model for the developing curriculum. In the research the curriculum is examined as an artefact, which shapes socio-technically under the influence of social and technical factors. In the perspective of socio-technical construction the artefact is represented by the viewpoints of members of relevant social groups. The groups give meaning to the curriculum artefact, which determines the components of the curriculum. The weakness of the curriculum was its ineffectiveness, which was due to three critical problems. Firstly, the curriculum was to be based on scientific work, which meant the development of schools through experiments and scientific research. Secondly, the civilised conseption in the curriculum was to be composed of theoretical knowledge, as well as practical skills. Practical education was useful for both the individual and society. Thirdly, the curriculum was to be reformed in a way that the individuality of the pupil would be taken into account. It was useful for the society that talents and natural abilities of every pupil were observed and used to direct the pupil to the proper place in the social division of labour, according to the "right man in a right place" principle. The solutions to critical problems formed the instructions of the public school curriculum, which described the nature and content of education. Technology and its development were on essential part of the whole school curriculum process. The quality words connected to the development of technology - progress, rationality and effectiveness - were also suitable qualifiers and reasons for the reform of the curriculum. On the other hand, technology set a point of comparison and demand for the development of all phases of education. The view of technology was not clearly deterministic - it was also possible to shape technological society with the help of education. The public school curriculum process indicates how originally the principles of technological systems were shaped to the language of education and accepted in educational content.

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Haptices and haptemes: A case study of developmental process in touch-based communication of acquired deafblind people This research is the first systematic, longitudinal process and development description of communication using touch and body with an acquired deafblind person. The research consists of observational and analysed written and video materials mainly from two informants´ experiences during period of 14 years. The research describes the adaptation of Social-Haptic methods between a couple, and other informants´ experiences, which have been collated from biographies and through giving national and international courses. When the hearing and sight deteriorates due to having an acquired deafblind condition, communication consists of multi-systematic and adaptive methods. A person`s expressive language, spoken or Sign Language, usually remains unchanged, but the methods of receiving information could change many times during a person s lifetime. Haptices are made from haptemes that determines which regulations are analysed. When defining haptemes the definition, classification and varied meanings of touch were discovered. Haptices include sharing a personal body space, meaning of touch-contact, context and using different communication channels. Communication distances are classified as exact distance, estimated distance and touch distance. Physical distance can be termed as very long, long, medium or very close. Social body space includes the body areas involved in sending and receiving haptices and applying different types of contacts. One or two hands can produce messages by using different hand shapes and orientations. This research classifies how the body can be identified into different areas such as body orientation, varied body postures, body position levels, social actions and which side of the body is used. Spatial body space includes environmental and situational elements. Haptemes of movements are recognised as the direction of movements, change of directions on the body, directions between people, pressure, speed, frequency, size, length, duration, pause, change of rhythm, shape, macro and micro movements. Haptices share multidimensional meanings and emotions. Research describes haptices in different situations enhancing sensory information and functioning also as an independent language. Haptices includes social-haptic confirmation system, social quick messages, body drawing, contact to the people and the environment, guiding and sharing art experiences through movements. Five stages of emotional differentiation were identified as very light, light, medium, heavy and very heavy touch. Haptices give the possibility to share different art, hobby and game experiences. A new communication system development based on the analysis of the research data is classified into different phases. These are experimental initiation, social deconstruction, developing the description of Social-Haptic communication and generalisation of the theory as well as finding and conceptualising the haptices and haptemes. The use and description of haptices is a social innovation, which illustrates the adaptive function of the body and perceptual senses that can be taught to a third party. Keywords: deafblindness, hapteme, haptic, haptices, movement, social-haptic communication, social-haptic confirmation system, tactile, touch

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Kaposi's sarcoma herpesvirus (KSHV) is an oncogenic human virus and the causative agent of three human malignancies: Kaposi's sarcoma (KS), Multicentric Castleman's Disease (MCD), and primary effusion lymphoma (PEL). In tumors, KSHV establishes latent infection during which it produces no infectious particles. Latently infected cells can enter the lytic replication cycle, and upon provision of appropriate cellular signals, produce progeny virus. PEL, commonly described in patients with AIDS, represents a diffuse large-cell non-Hodgkin's lymphoma, with median survival time less than six months after diagnosis. As tumor suppressor gene TP53 mutations occur rarely in PEL, the aim of this thesis was to investigate whether non-genotoxic activation of the p53 pathway can eradicate malignant PEL cells. This thesis demonstrates that Nutlin-3, a small-molecule inhibitor of the p53-MDM2 interaction, efficiently restored p53 function in PEL cells, leading to cell cycle arrest and massive apoptosis. Furthermore, we found that KSHV infection activated DNA damage signaling, rendering the cells more sensitive to p53-dependent cell death. We also showed in vivo the therapeutic potential of p53 restoration that led to regression of subcutaneous and intraperitoneal PEL tumor xenografts without adversely affecting normal cells. Importantly, we demonstrated that in a small subset of intraperitoneal PEL tumors, spontaneous induction of viral reactivation dramatically impaired Nutlin-3-induced p53-mediated apoptosis. Accordingly, we found that elevated KSHV lytic transcripts correlated with PEL tumor burden in animals and that inhibition of viral reactivation in vitro restored cytotoxic activity of a small-molecule inhibitor of the p53-MDM2 interaction. Latency provides a unique opportunity for KSHV to escape host immune surveillance and to establish persistent infections. However, to maintain viral reservoirs and spread to other hosts, KSHV must be reactivated from latency and enter into the lytic growth phase. We showed that phosphorylation of nucleolar phosphoprotein nucleophosmin (NPM) by viral cyclin-CDK6 is critical for establishment and maintenance of the KSHV latency. In short, this study provides evidence that the switch between latent phase and lytic replication is a critical step that determines the outcome of viral infection and the pathogenesis of KSHV-induced malignancies. Our data may thus contribute to development of novel targeted therapies for intervention and treatment of KSHV-associated cancers.

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One of the most important factors determining the development of atherosclerosis is the amount of LDL particles in the circulation. In general, LDL particles are clinically regarded as “bad cholesterol” since these particles get entrapped within the vascular wall, leading to atherosclerosis. Circulating HDL particles are conversely regarded as “good cholesterol” because of their ability to transport cholesterol from peripheral tissues to the liver for secretion as bile salts. Once inside the artery wall LDL particles are engulfed by macrophages, resulting in macrophage foam cells. If the macrophage foam cells are not able to efflux the cholesterol back into the bloodstream, the excessive cholesterol ultimately leads to cell death, and the deposition of cellular debris within the atherosclerotic lesion. The cells ability to secrete cholesterol is mainly dependent on the ABCA1 transporter (ATP-binding cassette transporter A1) which transfers cellular cholesterol to extracellular apoA-I (apolipoprotein A-I) particles, leading to the generation of nascent HDL particles. The process of atherosclerotic plaque development is therefore to a large extent a cellular one, in which the capacity of the macrophages in handling the excessive cholesterol load determines the progression of lesion development. In this work we have studied the cellular mechanisms that regulate the trafficking of LDL-derived cholesterol from endosomal compartments to other parts of the cell. As a basis for the study we have utilized cells from patients with Niemann-Pick type C disease, a genetic disorder resulting from mutations in the NPC1 and NPC2 genes. In these cells, cholesterol is entrapped within the endosomal compartment, and is not available for efflux. By identifying proteins that bypass the cholesterol trafficking defect, we were able to identify the small GTPase Rab8 as an important protein involved in ABCA1 dependent cholesterol efflux. In the study, we show that Rab8 regulates cholesterol efflux in human macrophages by facilitating intracellular cholesterol transport, as well as by regulating the plasma membrane availability of ABCA1. Collectively, these results give new insight in to atherosclerotic lesion development and intracellular cholesterol processing.

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Sprouting of fast-growing broad-leaved trees causes problems in young coniferous stands, under power transmission lines and along roads and railways. Public opinion and the Finnish Forest Certification System oppose the use of chemical herbicides to control sprouting, which means that most areas with problems rely on mechanical cutting. However, cutting is a poor control method for many broad-leaved species because the removal of leaders can stimulate the sprouting of side branches and cut stumps quickly re-sprout. In order to be effective, cutting must be carried out frequently but each cut increases the costs, making this control method increasingly difficult and expensive once begun. As such, alternative methods for sprout control that are both effective and environmentally sound represent a continuing challenge to managers and research biologists. Using biological control agents to prevent sprouting has been given serious consideration recently. Dutch and Canadian researchers have demonstrated the potential of the white-rot fungus Chondrostereum purpureum (Pers. ex Fr.) Pouzar as a control agent of stump sprouting in many hardwoods. These findings have focused the attention of the Finnish forestry community on the utilization of C. purpureum for biocontrol purposes. Primarily, this study sought determines the efficacy of native C. purpureum as an inhibitor of birch stump sprouting in Finland and to clarify its mode of action. Additionally, genotypic variation in Finnish C. purpureum was examined and the environmental risks posed by a biocontrol program using this fungus were assessed. Experimental results of the study demonstrated that C. purpureum clearly affects the sprouting of birch: both the frequency of living stumps and the number of living sprouts per stump were effectively reduced by the treatment. However, the treatment had no effect on the maximum height of new sprouts. There were clear differences among fungal isolates in preventing sprouting and those that possessed high oxidative activities as measured in the laboratory inhibited sprouting most efficiently in the field. The most effective treatment time during the growing season was in early and mid summer (May July). Genetic diversity in Nordic and Baltic populations of C. purpureum was found to be high at the regional scale but locally homogeneous. This natural distribution of diversity means that using local genotypes in biocontrol programs would effectively prevent the introduction of novel genes or genotypes. While a biocontrol program using local strains of C. purpureum would be environmentally neutral, pruned birches that are close to the treatment site would have a high susceptibility to infect by the fungus during the early spring.

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Strawberries (Fragaria sp.) are adapted to diverse environmental conditions from the tropics to about 70ºN, so different responses to environmental conditions can be found. Most genotypes of garden strawberry (F. x ananassa Duch.) and woodland strawberry (F. vesca L.) are short-day (SD) plants that are induced to flowering by photoperiods under a critical limit, but also various photoperiod x temperature interactions can be found. In addition, continuously flowering everbearing (EB) genotypes are found. In addition to flowering, axillary bud differentiation in strawberry is regulated by photoperiod. In SD conditions, axillary buds differentiate to rosette-like structures called "branch crowns", whereas in long-day conditions (LD) they form runners, branches with 2 long internodes followed by a daughter plant (leaf rosette). The number of crown branches determines the yield of the plant, since inflorescences are formed from the apical meristems of the crown. Although axillary bud differentiation is an important developmental process in strawberries, its environmental and hormonal regulation has not been characterized in detail. Moreover, the genetic mechanisms underlying axillary bud differentiation and regulation of flowering time in these species are almost completely unresolved. These topics have been studied in this thesis in order to enhance strawberry research, cultivation and breeding. The results showed that 8-12 SD cycles suppressed runner initiation from the axillary buds of the garden strawberry cv. Korona with the concomitant induction of crown branching, and 3 weeks of SD was sufficient for the induction of flowering in the main crown. Furthermore, a second SD treatment given a few weeks after the first SD period can be used to induce flowering in the primary branch crowns and to induce the formation of secondary branches. Thus, artificial SD treatments effectively stimulate crown branching, providing one means for the increase of cropping (yield) potential in strawberry. It was also shown by growth regulation applications, quantitave hormone analysis and gene expression analysis that gibberellin (GA) is one of the key signals involved in the photoperiod control of shoot differentiation. The results indicate that photoperiod controls GA activity specifically in axillary buds, thereby determining bud fate. It was further shown that chemical control of GA biosynthesis by prohexadione-calcium can be utilized to prevent excessive runner formation and induce crown branching in strawberry fields. Moreover, ProCa increased berry yield up to 50%, showing that it is an easier and more applicable alternative to artificial SD treatments for controlling strawberry crown development and yield. Finally, flowering gene pathways in Fragaria were explored by searching for homologs of 118 Arabidopsis thaliana flowering-time genes. In total, 66 gene homologs were identified, and they distributed to all known flowering pathways, suggesting the presence of these pathways also in strawberry. Expression analysis of selected genes revealed that the mRNA of putative floral identity gene APETALA1 accumulated in the shoot apex of the EB genotype after the induction of flowering, whereas it was absent in vegetative SD genotype, indicating the usefulness of this gene product as the marker of floral initiation. The present data enables the further exploration of strawberry flowering pathways with genetic transformation, gene mapping and transcriptomics methods.

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This thesis examines protein behaviours that occur during cereal fermentations. The focus is on the prolamin degradation in sourdoughs. The thesis also looks at what happens to the oat globulins during an oat bran acidification process. The cereal prolamins are unique proteins in many respects. The wheat prolamins (glutenins and gliadins) are responsible for the formation of the gluten that provides the viscoelastic properties to wheat doughs whereas the rye prolamins (secalins) are unable to develop gluten-like structures. In addition, many baking technological features, such as flavour, shelf-life and dough properties are affected by the protein degradation that might occur during processing. On the other hand, the prolamins contain protein structures that are harmful to gluten sensitive people. It is thus evident that the degradation of the prolamins in sourdough processes may be approached from various aspects. This thesis describes some of these approaches. Four different cereal fermentations were carried out. Wheat sourdough (WSD) and rye sourdough (RSD) fermentations represented traditional sourdoughs. A germinated-wheat sourdough (GWSD) was a novel sourdough type that was prepared using germinated wheat grains that had high and diverse proteolytic activities. The oat bran fermentation (OBF) represented a fermentation system that lacked functional cereal proteases. The high molecular weight glutenins and rye secalins were degraded during the WSD and RSD fermentations, respectively. It was noteworthy that in WSD only a very limited degradation of the gliadins occurred. The gliadins were, however, hydrolysed very extensively during the GWSD fermentation. No protein degradation was observable in the OBF system. Instead the acidification altered the solubility of the oat globulins and this finally led to their aggregation. This thesis confirms that the endogenous proteases of cereals hydrolyse cereal prolamins in sourdoughs. The thesis also shows that the proteolytic activity of the used cereal raw material determines the extent of proteolysis that occurs in sourdough. This means that bakers may adjust the protein degradation in their sourdoughs by selecting the raw material based on its proteolytic activity. The thesis also demonstrates that by using germinated grains, with high and diverse proteolytic activity in sourdough preparations, the prolamins can be extensively degraded. Whether such highly proteolytic food technology could be used to manufacture new gluten-free cereal-based products for gluten sensitive people remains to be solved.

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Individual movement is very versatile and inevitable in ecology. In this thesis, I investigate two kinds of movement body condition dependent dispersal and small-range foraging movements resulting in quasi-local competition and their causes and consequences on the individual, population and metapopulation level. Body condition dependent dispersal is a widely evident but barely understood phenomenon. In nature, diverse relationships between body condition and dispersal are observed. I develop the first models that study the evolution of dispersal strategies that depend on individual body condition. In a patchy environment where patches differ in environmental conditions, individuals born in rich (e.g. nutritious) patches are on average stronger than their conspecifics that are born in poorer patches. Body condition (strength) determines competitive ability such that stronger individuals win competition with higher probability than weak individuals. Individuals compete for patches such that kin competition selects for dispersal. I determine the evolutionarily stable strategy (ESS) for different ecological scenarios. My models offer explanations for both dispersal of strong individuals and dispersal of weak individuals. Moreover, I find that within-family dispersal behaviour is not always reflected on the population level. This supports the fact that no consistent pattern is detected in data on body condition dependent dispersal. It also encourages the refining of empirical investigations. Quasi-local competition defines interactions between adjacent populations where one population negatively affects the growth of the other population. I model a metapopulation in a homogeneous environment where adults of different subpopulations compete for resources by spending part of their foraging time in the neighbouring patches, while their juveniles only feed on the resource in their natal patch. I show that spatial patterns (different population densities in the patches) are stable only if one age class depletes the resource very much but mainly the other age group depends on it.

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Planar curves arise naturally as interfaces between two regions of the plane. An important part of statistical physics is the study of lattice models. This thesis is about the interfaces of 2D lattice models. The scaling limit is an infinite system limit which is taken by letting the lattice mesh decrease to zero. At criticality, the scaling limit of an interface is one of the SLE curves (Schramm-Loewner evolution), introduced by Oded Schramm. This family of random curves is parametrized by a real variable, which determines the universality class of the model. The first and the second paper of this thesis study properties of SLEs. They contain two different methods to study the whole SLE curve, which is, in fact, the most interesting object from the statistical physics point of view. These methods are applied to study two symmetries of SLE: reversibility and duality. The first paper uses an algebraic method and a representation of the Virasoro algebra to find common martingales to different processes, and that way, to confirm the symmetries for polynomial expected values of natural SLE data. In the second paper, a recursion is obtained for the same kind of expected values. The recursion is based on stationarity of the law of the whole SLE curve under a SLE induced flow. The third paper deals with one of the most central questions of the field and provides a framework of estimates for describing 2D scaling limits by SLE curves. In particular, it is shown that a weak estimate on the probability of an annulus crossing implies that a random curve arising from a statistical physics model will have scaling limits and those will be well-described by Loewner evolutions with random driving forces.

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This thesis studies optimisation problems related to modern large-scale distributed systems, such as wireless sensor networks and wireless ad-hoc networks. The concrete tasks that we use as motivating examples are the following: (i) maximising the lifetime of a battery-powered wireless sensor network, (ii) maximising the capacity of a wireless communication network, and (iii) minimising the number of sensors in a surveillance application. A sensor node consumes energy both when it is transmitting or forwarding data, and when it is performing measurements. Hence task (i), lifetime maximisation, can be approached from two different perspectives. First, we can seek for optimal data flows that make the most out of the energy resources available in the network; such optimisation problems are examples of so-called max-min linear programs. Second, we can conserve energy by putting redundant sensors into sleep mode; we arrive at the sleep scheduling problem, in which the objective is to find an optimal schedule that determines when each sensor node is asleep and when it is awake. In a wireless network simultaneous radio transmissions may interfere with each other. Task (ii), capacity maximisation, therefore gives rise to another scheduling problem, the activity scheduling problem, in which the objective is to find a minimum-length conflict-free schedule that satisfies the data transmission requirements of all wireless communication links. Task (iii), minimising the number of sensors, is related to the classical graph problem of finding a minimum dominating set. However, if we are not only interested in detecting an intruder but also locating the intruder, it is not sufficient to solve the dominating set problem; formulations such as minimum-size identifying codes and locating dominating codes are more appropriate. This thesis presents approximation algorithms for each of these optimisation problems, i.e., for max-min linear programs, sleep scheduling, activity scheduling, identifying codes, and locating dominating codes. Two complementary approaches are taken. The main focus is on local algorithms, which are constant-time distributed algorithms. The contributions include local approximation algorithms for max-min linear programs, sleep scheduling, and activity scheduling. In the case of max-min linear programs, tight upper and lower bounds are proved for the best possible approximation ratio that can be achieved by any local algorithm. The second approach is the study of centralised polynomial-time algorithms in local graphs these are geometric graphs whose structure exhibits spatial locality. Among other contributions, it is shown that while identifying codes and locating dominating codes are hard to approximate in general graphs, they admit a polynomial-time approximation scheme in local graphs.