34 resultados para allometric relationship

em Helda - Digital Repository of University of Helsinki


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An important challenge in forest industry is to get the appropriate raw material out from the forests to the wood processing industry. Growth and stem reconstruction simulators are therefore increasingly integrated in industrial conversion simulators, for linking the properties of wooden products to the three-dimensional structure of stems and their growing conditions. Static simulators predict the wood properties from stem dimensions at the end of a growth simulation period, whereas in dynamic approaches, the structural components, e.g. branches, are incremented along with the growth processes. The dynamic approach can be applied to stem reconstruction by predicting the three-dimensional stem structure from external tree variables (i.e. age, height) as a result of growth to the current state. In this study, a dynamic growth simulator, PipeQual, and a stem reconstruction simulator, RetroSTEM, are adapted to Norway spruce (Picea abies [L.] Karst.) to predict the three-dimensional structure of stems (tapers, branchiness, wood basic density) over time such that both simulators can be integrated in a sawing simulator. The parameterisation of the PipeQual and RetroSTEM simulators for Norway spruce relied on the theoretically based description of tree structure developing in the growth process and following certain conservative structural regularities while allowing for plasticity in the crown development. The crown expressed both regularity and plasticity in its development, as the vertical foliage density peaked regularly at about 5 m from the stem apex, varying below that with tree age and dominance position (Study I). Conservative stem structure was characterized in terms of (1) the pipe ratios between foliage mass and branch and stem cross-sectional areas at crown base, (2) the allometric relationship between foliage mass and crown length, (3) mean branch length relative to crown length and (4) form coefficients in branches and stem (Study II). The pipe ratio between branch and stem cross-sectional area at crown base, and mean branch length relative to the crown length may differ in trees before and after canopy closure, but the variation should be further analysed in stands of different ages and densities with varying site fertilities and climates. The predictions of the PipeQual and RetroSTEM simulators were evaluated by comparing the simulated values to measured ones (Study III, IV). Both simulators predicted stem taper and branch diameter at the individual tree level with a small bias. RetroSTEM predictions of wood density were accurate. For focusing on even more accurate predictions of stem diameters and branchiness along the stem, both simulators should be further improved by revising the following aspects in the simulators: the relationship between foliage and stem sapwood area in the upper stem, the error source in branch sizes, the crown base development and the height growth models in RetroSTEM. In Study V, the RetroSTEM simulator was integrated in the InnoSIM sawing simulator, and according to the pilot simulations, this turned out to be an efficient tool for readily producing stand scale information about stem sizes and structure when approximating the available assortments of wood products.

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The aim of this study is to examine the relationship of the Roman villa to its environment. The villa was an important feature of the countryside intended both for agricultural production and for leisure. Manuals of Roman agriculture give instructions on how to select a location for an estate. The ideal location was a moderate slope facing east or south in a healthy area and good neighborhood, near good water resources and fertile soils. A road or a navigable river or the sea was needed for transportation of produce. A market for selling the produce, a town or a village, should have been nearby. The research area is the surroundings of the city of Rome, a key area for the development of the villa. The materials used consist of archaeological settlement sites, literary and epigraphical evidence as well as environmental data. The sites include all settlement sites from the 7th century BC to 5th century AD to examine changes in the tradition of site selection. Geographical Information Systems were used to analyze the data. Six aspects of location were examined: geology, soils, water resources, terrain, visibility/viewability and relationship to roads and habitation centers. Geology was important for finding building materials and the large villas from the 2nd century BC onwards are close to sources of building stones. Fertile soils were sought even in the period of the densest settlement. The area is rich in water, both rainfall and groundwater, and finding a water supply was fairly easy. A certain kind of terrain was sought over very long periods: a small spur or ridge shoulder facing preferably south with an open area in front of the site. The most popular villa resorts are located on the slopes visible from almost the entire Roman region. A visible villa served the social and political aspirations of the owner, whereas being in the villa created a sense of privacy. The area has a very dense road network ensuring good connectivity from almost anywhere in the region. The best visibility/viewability, dense settlement and most burials by roads coincide, creating a good neighborhood. The locations featuring the most qualities cover nearly a quarter of the area and more than half of the settlement sites are located in them. The ideal location was based on centuries of practical experience and rationalized by the literary tradition.

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This dissertation examined the research-based teacher education at the University of Helsinki from different theoretical and practical perspectives. Five studies focused on these perspectives separately as well as overlappingly. Study I focused on the reflection process of graduating teacher students. The data consisted of essays the students wrote as their last assignment before graduating, where their assignment was to examine their development as researchers during their MA thesis research process. The results indicated that the teacher students had analysed their own development thoroughly during the process and that they had reflected on theoretical as well as practical educational matters. The results also pointed out that, in the students’ opinion, personally conducted research is a significant learning process. -- Study II investigated teacher students’ workplace learning and the integration of theory and practice in teacher education. The students’ interviews focused on their learning of teacher’s work prior to education. The interviewees’ responses concerning their ‘surviving’ in teaching prior to teacher education were categorized into three categories: learning through experiences, school as a teacher learning environment, and case-specific learning. The survey part of the study focused on integration of theory and practice within the education process. The results showed that the students who worked while they studied took advantage of the studies and applied them to work. They set more demanding teaching goals and reflected on their work more theoretically. -- Study III examined practical aspects of the teacher students’ MA thesis research as well as the integration of theory and practice in teacher education. The participants were surveyed using a web-based survey which dealt with the participants’ teacher education experiences. According to the results, most of the students had chosen a practical topic for their MA thesis, one arising from their work environment, and most had chosen a research topic that would develop their own teaching. The results showed that the integration of theory and practice had taken place in much of the course work, but most obviously in the practicum periods, and also in the courses concerning the school subjects. The majority felt that the education had in some way been successful with regards to integration. -- Study IV explored the idea of considering teacher students’ MA thesis research as professional development. Twenty-three teachers were interviewed on the subject of their experiences of conducting research about their own work as teachers. The results of the interviews showed that the reasons for choosing the MA thesis research topic were multiple: practical, theoretical, personal, professional reasons, as well as outside effect. The objectives of the MA thesis research, besides graduating, were actual projects, developing the ability to work as teachers, conducting significant research, and sharing knowledge of the topic. The results indicated that an MA thesis can function as a tool for professional development, for example in finding ways for adjusting teaching, increasing interaction skills, gaining knowledge or improving reflection on theory and/or practice, strengthening self-confidence as a teacher, increasing researching skills or academic writing skills, as well as becoming critical and being able to read scientific and academic literature. -- Study V analysed teachers’ views of the impact of practitioner research. According to the results, the interviewees considered the benefits of practitioner research to be many, affecting teachers, pupils, parents, the working community, and the wider society. Most of the teachers indicated that they intended to continue to conduct research in the future. The results also showed that teachers often reflected personally and collectively, and viewed this as important. -- These five studies point out that MA thesis research is and can be a useful tool for increasing reflection doing with personal and professional development, as well as integrating theory and practice. The studies suggest that more advantage could be taken of the MA thesis research project. More integration of working and studying could and should be made possible for teacher students. This could be done in various ways within teacher education, but the MA thesis should be seen as a pedagogical possibility.

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This thesis examines the mythology in and social reality behind a group of texts from the Nag Hammadi and related literature, to which certain leaders of the early church attached the label, Ophite, i.e., snake people. In the mythology, which essentially draws upon and rewrites the Genesis paradise story, the snake's advice to eat from the tree of knowledge is positive, the creator and his angels are demonic beasts and the true godhead is depicted as an androgynous heavenly projection of Adam and Eve. It will be argued that this unique mythology is attested in certain Coptic texts from the Nag Hammadi and Berlin 8502 Codices (On the Origin of the World, Hypostasis of the Archons, Apocryphon of John, Eugnostos, Sophia of Jesus Christ), as well as in reports by Irenaeus (Adversus Haereses 1.30), Origen (Contra Celsum 6.24-38) and Epiphanius (Panarion 26). It will also be argued that this so-called Ophite evidence is essential for a proper understanding of Sethian Gnosticism, often today considered one of the earliest forms of Gnosticism; there seems to have occurred a Sethianization of Ophite mythology. I propose that we replace the current Sethian Gnostic category by a new one that not only adds texts that draw upon the Ophite mythology alongside these Sethian texts, but also arranges the material in smaller typological units. I also propose we rename this remodelled and expanded Sethian corpus "Classic Gnostic." I have divided the thesis into four parts: (I) Introduction; (II) Myth and Innovation; (III) Ritual; and (IV) Conclusion. In Part I, the sources and previous research on Ophites and Sethians will be examined, and the new Classic Gnostic category will be introduced to provide a framework for the study of the Ophite evidence. Chapters in Part II explore key themes in the mythology of our texts, first by text comparison (to show that certain texts represent the Ophite mythology and that this mythology is different from Sethianism), and then by attempting to unveil social circumstances that may have given rise to such myths. Part III assesses heresiological claims of Ophite rituals, and Part IV is the conclusion.

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Democratic Legitimacy and the Politics of Rights is a research in normative political theory, based on comparative analysis of contemporary democratic theories, classified roughly as conventional liberal, deliberative democratic and radical democratic. Its focus is on the conceptual relationship between alternative sources of democratic legitimacy: democratic inclusion and liberal rights. The relationship between rights and democracy is studied through the following questions: are rights to be seen as external constraints to democracy or as objects of democratic decision making processes? Are individual rights threatened by public participation in politics; do constitutionally protected rights limit the inclusiveness of democratic processes? Are liberal values such as individuality, autonomy and liberty; and democratic values such as equality, inclusion and popular sovereignty mutually conflictual or supportive? Analyzing feminist critique of liberal discourse, the dissertation also raises the question about Enlightenment ideals in current political debates: are the universal norms of liberal democracy inherently dependent on the rationalist grand narratives of modernity and incompatible with the ideal of diversity? Part I of the thesis introduces the sources of democratic legitimacy as presented in the alternative democratic models. Part II analyses how the relationship between rights and democracy is theorized in them. Part III contains arguments by feminists and radical democrats against the tenets of universalist liberal democratic models and responds to that critique by partly endorsing, partly rejecting it. The central argument promoted in the thesis is that while the deconstruction of modern rationalism indicates that rights are political constructions as opposed to externally given moral constraints to politics, this insight does not delegitimize the politics of universal rights as an inherent part of democratic institutions. The research indicates that democracy and universal individual rights are mutually interdependent rather than oppositional; and that democracy is more dependent on an unconditional protection of universal individual rights when it is conceived as inclusive, participatory and plural; as opposed to robust majoritarian rule. The central concepts are: liberalism, democracy, legitimacy, deliberation, inclusion, equality, diversity, conflict, public sphere, rights, individualism, universalism and contextuality. The authors discussed are e.g. John Rawls, Jürgen Habermas, Seyla Benhabib, Iris Young, Chantal Mouffe and Stephen Holmes. The research focuses on contemporary political theory, but the more classical work of John S. Mill, Benjamin Constant, Isaiah Berlin and Hannah Arendt is also included.

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Cyclosporine is an immunosuppressant drug with a narrow therapeutic index and large variability in pharmacokinetics. To improve cyclosporine dose individualization in children, we used population pharmacokinetic modeling to study the effects of developmental, clinical, and genetic factors on cyclosporine pharmacokinetics in altogether 176 subjects (age range: 0.36–20.2 years) before and up to 16 years after renal transplantation. Pre-transplantation test doses of cyclosporine were given intravenously (3 mg/kg) and orally (10 mg/kg), on separate occasions, followed by blood sampling for 24 hours (n=175). After transplantation, in a total of 137 patients, cyclosporine concentration was quantified at trough, two hours post-dose, or with dose-interval curves. One-hundred-four of the studied patients were genotyped for 17 putatively functionally significant sequence variations in the ABCB1, SLCO1B1, ABCC2, CYP3A4, CYP3A5, and NR1I2 genes. Pharmacokinetic modeling was performed with the nonlinear mixed effects modeling computer program, NONMEM. A 3-compartment population pharmacokinetic model with first order absorption without lag-time was used to describe the data. The most important covariate affecting systemic clearance and distribution volume was allometrically scaled body weight i.e. body weight**3/4 for clearance and absolute body weight for volume of distribution. The clearance adjusted by absolute body weight declined with age and pre-pubertal children (< 8 years) had an approximately 25% higher clearance/body weight (L/h/kg) than did older children. Adjustment of clearance for allometric body weight removed its relationship to age after the first year of life. This finding is consistent with a gradual reduction in relative liver size towards adult values, and a relatively constant CYP3A content in the liver from about 6–12 months of age to adulthood. The other significant covariates affecting cyclosporine clearance and volume of distribution were hematocrit, plasma cholesterol, and serum creatinine, explaining up to 20%–30% of inter-individual differences before transplantation. After transplantation, their predictive role was smaller, as the variations in hematocrit, plasma cholesterol, and serum creatinine were also smaller. Before transplantation, no clinical or demographic covariates were found to affect oral bioavailability, and no systematic age-related changes in oral bioavailability were observed. After transplantation, older children receiving cyclosporine twice daily as the gelatine capsule microemulsion formulation had an about 1.25–1.3 times higher bioavailability than did the younger children receiving the liquid microemulsion formulation thrice daily. Moreover, cyclosporine oral bioavailability increased over 1.5-fold in the first month after transplantation, returning thereafter gradually to its initial value in 1–1.5 years. The largest cyclosporine doses were administered in the first 3–6 months after transplantation, and thereafter the single doses of cyclosporine were often smaller than 3 mg/kg. Thus, the results suggest that cyclosporine displays dose-dependent, saturable pre-systemic metabolism even at low single doses, whereas complete saturation of CYP3A4 and MDR1 (P-glycoprotein) renders cyclosporine pharmacokinetics dose-linear at higher doses. No significant associations were found between genetic polymorphisms and cyclosporine pharmacokinetics before transplantation in the whole population for which genetic data was available (n=104). However, in children older than eight years (n=22), heterozygous and homozygous carriers of the ABCB1 c.2677T or c.1236T alleles had an about 1.3 times or 1.6 times higher oral bioavailability, respectively, than did non-carriers. After transplantation, none of the ABCB1 SNPs or any other SNPs were found to be associated with cyclosporine clearance or oral bioavailability in the whole population, in the patients older than eight years, or in the patients younger than eight years. In the whole population, in those patients carrying the NR1I2 g.-25385C–g.-24381A–g.-205_-200GAGAAG–g.7635G–g.8055C haplotype, however, the bioavailability of cyclosporine was about one tenth lower, per allele, than in non-carriers. This effect was significant also in a subgroup of patients older than eight years. Furthermore, in patients carrying the NR1I2 g.-25385C–g.-24381A–g.-205_-200GAGAAG–g.7635G–g.8055T haplotype, the bioavailability was almost one fifth higher, per allele, than in non-carriers. It may be possible to improve individualization of cyclosporine dosing in children by accounting for the effects of developmental factors (body weight, liver size), time after transplantation, and cyclosporine dosing frequency/formulation. Further studies are required on the predictive value of genotyping for individualization of cyclosporine dosing in children.

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There is considerable evidence that children in modern society are losing
their contact with nature and, more precisely, with green plants. Is this also the case in Finland, a northern country famous for its forests and wild nature? This study examines the relationship of 9- to 10-year-old Finnish schoolchildren with the green environment and plants. The data were gathered by a questionnaire
comprising structured and open-ended questions. The focus of the research was on two comparisons: first, on the nature and child relationship in rural and urban neighborhoods and, second, among boys and girls. Participants in the study amounted to a total of 76 children, 42 in the Helsinki suburb area and 34 in Paltamo. The results suggested that the children in rural surroundings had closer contact with nature than their urban associates. For example, the children of Paltamo reported to know the trees better, and considered human beings to be part of nature more often (100% vs. 76% of the pupils in Helsinki, P = 0,003). Similarly, the results showed that girls in the study (N = 48) were more interested in plants than boys (N = 28). For the girls, the beauty and joy of plants was important, whereas the boys appreciated plants as the source of life. After the pre-questioning, the children of Helsinki participated in an in-class horticultural intervention and 10 days later, answered a similar questionnaire again. The results of the open-ended questions revealed that equally to children in other Western countries, Finnish children may also be in danger of losing their direct contact with the natural environment. It was common to pass free time in organized sports such as hockey or football (boys), or by just walking and talking with friends (girls). Rural children told that they still built huts, pick berries, and climb trees, whereas urban children played in parks and city groves. The results suggest that it is essential to research
further the children’s own experiences if we are to understand, and subsequently, to enhance, the crucial role of the green environment in their lives. Horticultural interventions can be effective starting points to add to children’s knowledge, affection, and interest toward greenery, but it is highly recommended that they take place outdoors rather than indoors.

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There is considerable evidence that children in modern society are losing
their contact with nature and, more precisely, with green plants. Is this also the case in Finland, a northern country famous for its forests and wild nature? This study examines the relationship of 9- to 10-year-old Finnish schoolchildren with the green environment and plants. The data were gathered by a questionnaire
comprising structured and open-ended questions. The focus of the research was on two comparisons: first, on the nature and child relationship in rural and urban neighborhoods and, second, among boys and girls. Participants in the study amounted to a total of 76 children, 42 in the Helsinki suburb area and 34 in Paltamo. The results suggested that the children in rural surroundings had closer contact with nature than their urban associates. For example, the children of Paltamo reported to know the trees better, and considered human beings to be part of nature more often (100% vs. 76% of the pupils in Helsinki, P = 0,003). Similarly, the results showed that girls in the study (N = 48) were more interested in plants than boys (N = 28). For the girls, the beauty and joy of plants was important, whereas the boys appreciated plants as the source of life. After the pre-questioning, the children of Helsinki participated in an in-class horticultural intervention and 10 days later, answered a similar questionnaire again. The results of the open-ended questions revealed that equally to children in other Western countries, Finnish children may also be in danger of losing their direct contact with the natural environment. It was common to pass free time in organized sports such as hockey or football (boys), or by just walking and talking with friends (girls). Rural children told that they still built huts, pick berries, and climb trees, whereas urban children played in parks and city groves. The results suggest that it is essential to research
further the children’s own experiences if we are to understand, and subsequently, to enhance, the crucial role of the green environment in their lives. Horticultural interventions can be effective starting points to add to children’s knowledge, affection, and interest toward greenery, but it is highly recommended that they take place outdoors rather than indoors.

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There is considerable evidence that children in modern society are losing
their contact with nature and, more precisely, with green plants. Is this also the case in Finland, a northern country famous for its forests and wild nature? This study examines the relationship of 9- to 10-year-old Finnish schoolchildren with the green environment and plants. The data were gathered by a questionnaire
comprising structured and open-ended questions. The focus of the research was on two comparisons: first, on the nature and child relationship in rural and urban neighborhoods and, second, among boys and girls. Participants in the study amounted to a total of 76 children, 42 in the Helsinki suburb area and 34 in Paltamo. The results suggested that the children in rural surroundings had closer contact with nature than their urban associates. For example, the children of Paltamo reported to know the trees better, and considered human beings to be part of nature more often (100% vs. 76% of the pupils in Helsinki, P = 0,003). Similarly, the results showed that girls in the study (N = 48) were more interested in plants than boys (N = 28). For the girls, the beauty and joy of plants was important, whereas the boys appreciated plants as the source of life. After the pre-questioning, the children of Helsinki participated in an in-class horticultural intervention and 10 days later, answered a similar questionnaire again. The results of the open-ended questions revealed that equally to children in other Western countries, Finnish children may also be in danger of losing their direct contact with the natural environment. It was common to pass free time in organized sports such as hockey or football (boys), or by just walking and talking with friends (girls). Rural children told that they still built huts, pick berries, and climb trees, whereas urban children played in parks and city groves. The results suggest that it is essential to research
further the children’s own experiences if we are to understand, and subsequently, to enhance, the crucial role of the green environment in their lives. Horticultural interventions can be effective starting points to add to children’s knowledge, affection, and interest toward greenery, but it is highly recommended that they take place outdoors rather than indoors.