5 resultados para generic exponential family duration modeling

em Helda - Digital Repository of University of Helsinki


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Financial time series tend to behave in a manner that is not directly drawn from a normal distribution. Asymmetries and nonlinearities are usually seen and these characteristics need to be taken into account. To make forecasts and predictions of future return and risk is rather complicated. The existing models for predicting risk are of help to a certain degree, but the complexity in financial time series data makes it difficult. The introduction of nonlinearities and asymmetries for the purpose of better models and forecasts regarding both mean and variance is supported by the essays in this dissertation. Linear and nonlinear models are consequently introduced in this dissertation. The advantages of nonlinear models are that they can take into account asymmetries. Asymmetric patterns usually mean that large negative returns appear more often than positive returns of the same magnitude. This goes hand in hand with the fact that negative returns are associated with higher risk than in the case where positive returns of the same magnitude are observed. The reason why these models are of high importance lies in the ability to make the best possible estimations and predictions of future returns and for predicting risk.

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Natural products constitute an important source of new drugs. The bioavailability of the drugs depends on their absorption, distribution, metabolism and elimination. To achieve good bioavailability, the drug must be soluble in water, stable in the gastrointestinal tract and palatable. Binding proteins may improve the solubility of drug compounds, masking unwanted properties, such as bad taste, bitterness or toxicity, transporting or protecting these compounds during processing and storage. The focus of this thesis was to study the interactions, including ligand binding and the effect of pH and temperature, of bovine and reindeer β-lactoglobulin (βLG) with such compounds as retinoids, phenolic compounds as well as with compounds from plant extracts, and to investigate the transport properties of the βLG-ligand complex. To examine the binding interactions of different ligands to βLG, new methods were developed. The fluorescence binding method for the evaluation of ligand binding to βLG was miniaturized from a quartz cell to a 96-well plate. A method of ultrafiltration sampling combined with high-performance liquid chromatography was developed to assess the binding of compounds from extracts. The interactions of phenolic compounds or retinoids and βLG were investigated using the 96-well plate method. The majority of flavones, flavonols, flavanones and isoflavones and all of the retinoids included were shown to bind to bovine and reindeer βLG. Phenolic compounds, contrary to retinol, were not released at acidic pH. Those results suggest that βLG may have more binding sites, probably also on the surface of βLG. An extract from Camellia sinensis (L.) O. Kunze (black tea), Urtica dioica L. (nettle) and Piper nigrum (black pepper) were used to evaluate whether βLG could bind compounds from plant extracts. Piperine from P. nigrum was found to bind tightly and rutin from U. dioica weakly to βLG. No components from C. sinensis bound to βLG in our experiment. The uptake and membrane permeation of bovine and reindeer βLG, free and bound with retinol, palmitic acid and cholesterol, were investigated using Caco-2 cell monolayers. Both bovine and reindeer βLG were able to cross the Caco-2 cell membrane. Free and βLG-bound retinol and palmitic acid were transported equally, whereas cholesterol could not cross the Caco-2 cell monolayer free or bound to βLG. Our results showed that βLG can bind different natural product compounds, but cannot enhance transport of retinol, palmitic acid or cholesterol through Caco-2 cells. Despite this, βLG, as a water-soluble binding protein, may improve the solubility of natural compounds, possibly protecting them from early degradation and transporting some of them through the stomach. Furthermore, it may decrease their bad or bitter taste during oral administration of drugs or in food preparations. βLG can also enhance or decrease the health benefits of herbal teas and food preparations by binding compounds from extracts.

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Poetics of Awakenings. Genres and Intertexts in Arvid Järnefelt s Novels Isänmaa, Maaemon lapsia and Veneh ojalaiset This doctoral dissertation focuses on Arvid Järnefelt s (1961 1932) novels Isänmaa (1893), Maaemon lapsia (1905) and Veneh ojalaiset (1909). The study applies the genre theory and concepts Alastair Fowler has introduced in his Kinds of Literature (1982). Fowler s theory of the novel is developed further and applied to Finnish realist novels. The generic analysis is supplemented by intertextual analysis, which is mainly based on the idea of specific intertextual relations as presented by Kiril Taranovsky. Generic and intertextual analyses form the basis for hermeneutic interpretation, in which attention is paid to the fact that the novels are written by the designated writer in specific historical and cultural circumstances. Instead of the author s intention , the study focuses on the realised intention , in other words the novels as they are published. Järnefelt s first novel Isänmaa is understood to be a classical Bidungsroman that depicts the socialisation of a young male protagonist. From an intertextual point of view, the novel appears to be a novel of conversion, too, due to the biblical allusions concealed in the depiction of the events. Furthermore, Isänmaa is seen to stand in an intertextual relation to Hegel s, Snellman s and Topelius s writings. Maaemon lapsia is argued to be a thesis novel, which persuades the reader to adopt a certain ideological and political stance, namely Henry George s view on the private ownership of land. The novel is modulated by the generic repertoires of fairy tale and tragedy. The mythical frame of the novel supports the thesis novel, as it gives universal validity to the particular events depicted in the novel. Maaemon lapsia also comments on the contemporary political debate on the relations between Finland and Russia by presenting the relationship as analogous to the relationship between tenant farmer and landowner. Veneh ojalaiset exhibits a wide range of genres. Comic, tragic and mythical mode is combined with, for example, family novel, romance, conversion novel and revolutionary novel. From a rhetorical viewpoint, the novel is an apology, which accuses society of generating criminality by means of unjust laws and procedures. The novel discusses the question of resistance to evil by using the themes of Faust and Job, as well as by confronting the philosophies of Epictetus and Nietzsche. The novel is a thesis novel, which disputes the possibility of violent revolution as a way to a better society and recommends passive resistance for an individual living in an unjust society. The poetics of Järnefelt s novels is regarded as the poetics of conversion, as all the novels in focus depict the protagonist s awakening to see the society in a new light, be it a patriotic vision of the reality or a conception of the unfairness of society.

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How toddlers with special needs adjust to the daycare setting A multiple case study of how the relationships with adults and children are built The aim in this study is to describe how toddlers with special needs adjust to daycare. The emotional well-being and involvement in daycare activities of toddlers are especially investigated in this study. The relationship and how it is built between an adult and a child, a child and a child is examined. The daycare is examined through the socio-cultural theory as a pedagogical institution, where the child adapts by participating in social and cultural activities with the others. The development of the child is the result of the experiences that are gained through the constant relationship between the child, the family and social context. By the attachment theory the inner self-regulation, that allows the child safely adapt to new situations, develops most in the relationship between the child under 3years of age and the attending adult. The relationships between toddlers in daycare are usually built by the coincidental encounters in play and daily activities. In these relationships, the toddler gets the information of themselves and the other children. The complexity of the rules in the setting that organize the social action is challenging for the children and they need constant support from the adults. The participants of the study were five toddlers with special needs. When applying to daycare they were less than three years old and they got the specialist statement for their special needs, and the reference for daycare. The children were observed by recording their attending in the daycare once in the 3-4 months from the first day in daycare. Approximately 15 hours of material that was analysed with the Transana-program. The qualitative material was analysed by first collecting a descriptive model that explains and theorises the phenomenon. By the summery of the narrative it is placed a hypothesis that is tested by quantitative methods using correlations and variance analyses and general linear modeling that is used to count the differences between repeated measures and connections between different variables. The results of the study are built theoretically for the consistent conception between the theory and the findings in research. The toddlers in the study were all dependent on the support given by the adults in all the situations in the daycare. They could not associate with the other children without the support of the adults and their involvement in activities was low. The engagement of an adult in interaction was necessary for the children’s involvement in activities, and the co-operation with the other children. The engagement of teachers was statistically significantly higher than the engagement of other professions.