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Protein Folding Studies on the Ribosomal Protein S6: the Role of Entropy in NucleationLindberg, Magnus January 2005 (has links)
One of the most challenging tasks remaining in the field of biochemistry is the one of understanding how the information within the amino acid sequence of proteins translates into a unique structure. Solving this problem would lead to endless possibilities for application in the medical and biotechnology industry. Many decades ago scientists realized that the process that facilitates the folding of a polypeptide chain could not be random and happen by chance; there needs to be direction in the folding free energy landscape. This landscape is defined by the thermodynamic factors entropy and enthalpy. The contribution made by enthalpy i.e. the contact energies from intra- and intermolecular interactions have been extensively investigated by various mutational studies. The influence of entropy on the other hand, is less well understood. My work focuses on the effect of altering the entropic components of forming the various parts of a known protein scaffold. This is done by genetic engineering in combination with biophysical characterisation and analysis. The results show effects on protein folding rates as well as on the pathway for nucleation and emphasis the ability of the folding landscape to readjust to entropic variations. Proteins are therefore not required to fold along a unique route to their final structure but can do so in several ways. The folding pathways we observe today have hence likely evolved as an adaptation to biological demands.
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Nomadic Writing : Exploring Processes of Writing in Early Childhood EducationHermansson, Carina January 2013 (has links)
This thesis explores how writing is made in two Swedish early childhood classrooms with a focus on how processes of writing are constituted in the writing event and what writings and writers the event offers potentials for. Theoretically, the research project takes its starting point in the assumption that processes of writing are an effect of relations between different elements, where the young writer is only one part of many human and non-human matters that make way for multiple becomings of writing and writers. In this context, the figuration of the nomad thought of Deleuze and Guattari is particularly applicable as it builds on the assumption that everything is always connected, continuously moving. The questions addressed are how the processes of writers, text-like writings and educational writing processes emerge, continue and transform in the writing event, and what writers, text-like writings and educational writing processes the event offers potentials for. The thesis consists of three research articles based on different empirical data. The first article builds on data from the thinking and talking about writing and the writing child in scholarly literature since the 19th century. The second and third articles are based on analyses of ethnographic documentation of six- to seven-year-olds’ writing activities in two early childhood classrooms. The ethnographic strategies of the audio and video recordings, field notes, informal interviews and the collection of children’s text-like writings were carried out over a period of one and a half year during which the children moved from preschool class to their first year of school. The findings of the first article suggest that the image of the ideal writing and the ideal writer has changed over time. However, the image of the young writer training for adult life predominates over time. The main result of the second article shows in specific ways that the mutual production of stabilizing processes of writing and processes of experimentation are vital components for becomings of writers and writing, irrespective of pedagogical framings. The finding of the third article illustrates how the teaching method of creative writing produced over time creates multiple pedagogical trajectories of “doing method” and “doing creativity”. The thesis posits nomadic writing as a way to account for the movement, the connectivity and change in the processes of writing, thus contributing to an understanding of how the processes of writing create potentialities for multiple becomings of writers and writing. / Baksidestext/Blurb How is writing made? How do processes of writing emerge, continue and change in educational writing events? And what kinds of writers and writings can potentially emerge from the writing event? In this thesis Carina Hermansson explores how writing is produced in early childhood education, partly through analyses of the thinking and talking about writing and the writing child provided in scholarly literature since the 19th century, and partly through analyses of ethnographic documentation of six- to seven-year-olds’ writing activities in two early childhood classrooms. The research identifies how the processes of writing are an effect of many elements assembled in the writing event, such as computers, learning outcomes, bodily movements, children and teachers, and experiences based on children’s popular cultures. Hermansson posits nomadic writing as a way to account for the connectivity, the movement and change in the processes of writing, thus contributing to an understanding of how the processes of writing create potentialities for multiple becomings of writers and writing. The findings show that the mutual production of stabilizing processes of writing and processes of experimentation are vital components for becomings of writers and writing, thus offering a way to view early childhood writing classrooms as sites of experimentation. Nomadic Writing: Exploring processes of writing in early childhood education is a book about children’s writing and writing development in a society where media, digital technology and new forms of communication and literacy are conceptualized as important in education. It provides researchers and teachers with a conceptual framework for understanding the dynamic processes of writing. / <p>The online version of the thesis differs slightly from the printed version as research articles have been removed for copyright reasons.</p>
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Nomadic writing : exploring processes of writing in early childhood educationHermansson, Carina January 2013 (has links)
This thesis explores how writing is made in two Swedish early childhood classrooms with a focus on how processes of writing are constituted in the writing event and what writings and writers the event offers potentials for. Theoretically, the research project takes its starting point in the assumption that processes of writing are an effect of relations between different elements, where the young writer is only one part of many human and non-human matters that make way for multiple becomings of writing and writers. In this context, the figuration of the nomad thought of Deleuze and Guattari is particularly applicable as it builds on the assumption that everything is always connected, continuously moving. The questions addressed are how the processes of writers, text-like writings and educational writing processes emerge, continue and transform in the writing event, and what writers, text-like writings and educational writing processes the event offers potentials for. The thesis consists of three research articles based on different empirical data. The first article builds on data from the thinking and talking about writing and the writing child in scholarly literature since the 19th century. The second and third articles are based on analyses of ethnographic documentation of six- to seven-year-olds’ writing activities in two early childhood classrooms. The ethnographic strategies of the audio and video recordings, field notes, informal interviews and the collection of children’s text-like writings were carried out over a period of one and a half year during which the children moved from preschool class to their first year of school. The findings of the first article suggest that the image of the ideal writing and the ideal writer has changed over time. However, the image of the young writer training for adult life predominates over time. The main result of the second article shows in specific ways that the mutual production of stabilizing processes of writing and processes of experimentation are vital components for becomings of writers and writing, irrespective of pedagogical framings. The finding of the third article illustrates how the teaching method of creative writing produced over time creates multiple pedagogical trajectories of “doing method” and “doing creativity”. The thesis posits nomadic writing as a way to account for the movement, the connectivity and change in the processes of writing, thus contributing to an understanding of how the processes of writing create potentialities for multiple becomings of writers and writing.
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Influence of lakes and peatlands on groundwater contribution to Boreal streamflow2013 March 1900 (has links)
How much groundwater flows to boreal streams depends on the relative contributions from each landscape unit (forested uplands, lakes, and peatlands) within a catchment along with its hydrogeologic setting. Although there is an understanding of the hydrologic processes that regulate groundwater outputs from individual landscape units to their underlying aquifers (both coarse- and fine-textured) in the boreal forest, less understood is how the topography, typology, and topology (i.e. hydrologic connectivity) of the landscape units regulates groundwater flow to streams. Improved understanding of groundwater-stream interactions in the Boreal Plain of Alberta and Saskatchewan is critical as this region is undergoing substantial environmental change from land cover disturbances for energy and forestry industries and climate change. This thesis determines groundwater-stream interactions during the autumn low-flow period in a 97 km2 glacial outwash sub-catchment of White Gull Creek Research Basin, Boreal Ecosystem Research and Modelling Site, Saskatchewan. The catchment (Pine Fen Creek) is comprised of a large (30 km2) valley-bottom peatland, two lakes, and jack pine (Pinus banksiana) uplands. The pine uplands are important areas of annual groundwater recharge for the catchment. Vertical hydraulic gradients (VHGs) show frequent flow reversals between the lakes and sand aquifer, and spatially diverse VHGs between the peatland and sand aquifer. Groundwater flow nets and lateral hydraulic gradients indicate the stream receives groundwater along its length. Isotopic samples of end members corroborate the hydrometric data. Catchment streamflow response during the 2011 low flow period was not simply the addition of net groundwater inputs from each landscape unit. Instead, the large size, valley-bottom position, and short water ‘memory’ of the peatland were the critical factors in regulation of catchment streamflow during low flow periods. Peatland hydrologic function alternated between a source and sink of runoff (surface and subsurface) to the stream, dependent on the position of the water table; a value of 0.15 m below peat surface was the critical functional tipping point. Given the high percentage of peatlands (21%) within the Boreal Plain, incorporating their runoff threshold is required in parameterizing runoff generation in hydrological models, and thus predicting impacts of peatland degradation and forest clearing on streamflow.
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Connectivity and runoff dynamics in heterogeneous drainage basinsPhillips, Ross Wilson 16 March 2011
A drainage basins runoff response can be determined by the connectivity of generated runoff to the stream network and the connectivity of the downstream stream network. The connectivity of a drainage basin modulates its ability to produce streamflow and respond to precipitation events and is a function of the complex and variable storage capacities along the drainage network. An improved means to measure and account for the dynamics of hydrological connectivity at the basin scale is needed to improve prediction of basin scale streamflow. The overall goal of this thesis is to improve the understanding of hydrological connectivity at the basin scale by measuring hydrological connectivity at the Baker Creek Research Basin during 2009. To this end, the objectives are to 1) investigate the dynamics of hydrological connectivity during a typical water year, 2) define the relationship between the contributing stream network and contributing area, 3) investigate how hydrological connectivity influences streamflow, and 4) define how hydrological connectivity influences runoff response to rainfall events. At a 150 km2 subarctic Precambrian Shield catchment where the poorly-drained heterogeneous mosaic of lakes, exposed bedrock, and soil filled areas creates variable contributing areas, hydrological connectivity was measured between April and September 2009 in 10 sub-basins with a particular focus on three representative sub-basins. The three sub-basins, although of similar relative size, vary considerably in the dominant typology and topology of their constituent elements. At a 10 m spatial resolution, saturated areas were mapped using both multispectral satellite imagery and in situ measurements of storage according to land cover. To measure basin scale hydrological connectivity, the drainage network was treated as a graph network with stream reaches being the edges that connect sub-catchment nodes. The overall hydrological connectivity of the stream network was described as the ratio of actively flowing relative to potentially flowing stream reaches, and the hydrological connectivity of the stream network to the outlet was described as the ratio of actively flowing stream reaches that were connected to the outlet relative to the potentially flowing stream reaches. Hydrological connectivity was highest during the spring freshet but the stream network began to disintegrate with its passing. In some drainage basins, large gate keepers were able to maintain connectivity of the stream network downstream during dry periods. The length of the longest stream was found to be proportional to contributing area raised to a power of 0.605, similar to that noted in Hacks Law and modified Hacks Law relationships. The length of the contributing stream network was also found to be proportional to contributing area raised to a power of 0.851. In general, higher daily average streamflows were noted for higher states of connectivity to the outlet although preliminary investigations allude to the existence of hysteresis in these relationships. Elevated levels of hydrological connectivity were also found to yield higher basin runoff ratios but the shape of the characteristic curve for each basin was heavily influenced by key traits of its land cover heterogeneity. The implications of these findings are that accurate prediction of streamflow and runoff response in a heterogeneous drainage basin with dynamic connectivity will require both an account of the presence or absence of connections but also a differentiation of connection type and an incorporation of aspects of local function that control the flow through connections themselves. The improved understanding of causal factors for the variable streamflow response to runoff generation in this environment will serve as a first step towards developing improved streamflow prediction methods in formerly glaciated landscapes, especially in small ungauged basins.
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Transformative power of creative process in learning : defining a path to relational connections with the environmentBlom, Monique R 24 August 2011
This project offers an analysis of how the transformative power of creative process in learning offers humankind relational connections with the natural environment. It supports the recommendation that educational institutions move towards a transformative creative learning process. The paper argues that by teaching children through assumptions of the world as in constant creative becoming humankind will move toward
a more encompassing, coherent story of the universe which allows for the increasing self-actualization of individuals. After offering a theoretical discussion of the transformative power of creativity through the works of Brian Swimme, Edmund OSullivan and Alfred North Whitehead, the author provides descriptive, interpretive and critical narrative accounts of a teaching occasion created by her in which she illustrates her understanding of this transformative power.
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Exurban Development: Mapping, Locating Factors, and Ecological Impact Analysis using GIS and Remote SensingShrestha, Namrata 31 August 2012 (has links)
Anthropogenic disturbance in a landscape can take various forms, including residential development, which has substantial impact on the world’s ecosystems. Exurban development, characterized by low density residential development outside urban areas, was and continues to be one of the fastest growing forms of residential development in North America. It has disproportionately large ecological impacts relative to its footprint, yet is mostly overlooked in scientific studies. Specifically, a lack of spatially explicit (disaggregate) data on exurban development at regional level has contributed to a very limited understanding of this interspersed low density development.
The main goal of this dissertation is to provide an increased understanding of exurban development in terms of its location, locating factors, and conservation and ecological implications at regional level, especially to enable incorporation of exurban information in the decision making processes. For this I asked four specific questions in this dissertation: (i) Where exactly is exurban development? (ii) What are the most likely factors that influence exurban development location? (iii) How does current and future development conflict with conservation goals? And (iv) What is the extent of the exurban development’s ecological impacts? Using a heterogeneous landscape, the County of Peterborough (Ontario, Canada), as the case study this dissertation undertook a number of separate yet related analyses that collectively provided the improved understanding of exurban development. The investigation of traditionally used surrogates for development, like roads and census data, and a more direct remote sensing method, using moderate resolution SPOT/HRVIR imagery, provided insights and contributed to development of spatially explicit data on exurban development. The evaluation of several commonly hypothesized locating factors in relation to exurban development revealed some of the major influences on the location of this development, especially in the context of Ontario. This research contributed to our understanding of the future risks of land conversion and identification of potential conflict areas between development and conservation plans in the study area. Lastly, examining the ecological impact of exurban development including associated roads, in terms of functions such as barrier effects and landscape connectivity, highlighted the importance of these seldom included anthropogenic disturbances in land and conservation planning.
The contributions of this research to the existing body of knowledge are threefold. First, this dissertation reveals the limitations associated with existing methods used to map exurban development and presents a relatively easy, effective, automated and operational method to delineate exurban built areas at regional level using GIS and remote sensing. Second, the analyses conducted in this dissertation repeatedly highlights the importance of incorporating fine level details on exurban development in land and conservation planning as well as ecological impact assessments and presents methods and tools that can systematically and scientifically integrate this information in decision making framework. Third, this study conducted one of a kind, comprehensive and spatially explicit study on exurban development in Canada, where there is near absence of such research. With the rarely available exurban built footprint data delineated for the study area, this study not only identified the potential locating factors, future conversion risk, and conflict areas between development and conservation plans, but also quantified ecological impact in terms of landscape function, namely barrier effects and landscape connectivity, using a relatively novel circuit theoretic approach that can directly inform land and conservation decision planning process.
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Horizontale und vertikale Konnektivität in Fließgewässern und Seen : ökologische Funktionen und anthropogene Überformung / Horizontal and vertical connectivity in rivers and lakes : ecological functions and anthropogenic transformationPusch, Martin January 2012 (has links)
Gewässer werden traditionellerweise als abgeschlossene Ökosysteme gesehen, und insbeson¬dere das Zirkulieren von Wasser und Nährstoffen im Pelagial von Seen wird als Beispiel dafür angeführt. Allerdings wurden in der jüngeren Vergangenheit wichtige Verknüpfungen des Freiwasserkörpers von Gewässern aufgezeigt, die einerseits mit dem Benthal und andererseits mit dem Litoral, der terrestrischen Uferzone und ihrem Einzugsgebiet bestehen.
Dadurch hat in den vergangen Jahren die horizontale und vertikale Konnektivität der Gewässerökosysteme erhöhtes wissenschaftliches Interesse auf sich gezogen, und damit auch die ökologischen Funktionen des Gewässergrunds (Benthal) und der Uferzonen (Litoral). Aus der neu beschriebenen Konnektivität innerhalb und zwischen diesen Lebensräumen ergeben sich weitreichende Konsequenzen für unser Bild von der Funktionalität der Gewässer.
In der vorliegenden Habilitationsschrift wird am Beispiel von Fließgewässern und Seen des nordostdeutschen Flachlandes eine Reihe von internen und externen funktionalen Verknüpfungen in den horizontalen und vertikalen räumlichen Dimensionen aufgezeigt. Die zugrunde liegenden Untersuchungen umfassten zumeist sowohl abiotische als auch biologische Variablen, und umfassten thematisch, methodisch und hinsichtlich der Untersuchungsgewässer ein breites Spektrum. Dabei wurden in Labor- und Feldexperimenten sowie durch quantitative Feldmes¬sungen ökologischer Schlüsselprozesse wie Nährstoffretention, Kohlenstoffumsatz, extrazellu¬läre Enzymaktivität und Ressourcenweitergabe in Nahrungsnetzen (mittels Stabilisotopen¬methode) untersucht.
In Bezug auf Fließgewässer wurden dadurch wesentliche Erkenntnisse hinsichtlich der Wirkung einer durch Konnekticität geprägten Hydromorphologie auf die die aquatische Biodiversität und die benthisch-pelagische Kopplung erbracht, die wiederum einen Schlüsselprozess darstellt für die Retention von in der fließenden Welle transportierten Stoffen, und damit letztlich für die Produktivität eines Flussabschnitts.
Das Litoral von Seen wurde in Mitteleuropa jahrzehntelang kaum untersucht, so dass die durchgeführten Untersuchungen zur Gemeinschaftsstruktur, Habitatpräferenzen und Nahrungs¬netzverknüpfungen des eulitoralen Makrozoobenthos grundlegend neue Erkenntnisse erbrach¬ten, die auch unmittelbar in Ansätze zur ökologischen Bewertung von Seeufern gemäß EG-Wasserrahmenrichtlinie eingehen.
Es konnte somit gezeigt werden, dass die Intensität sowohl die internen als auch der externen ökologischen Konnektivität durch die Hydrologie und Morphologie der Gewässer sowie durch die Verfügbarkeit von Nährstoffen wesentlich beeinflusst wird, die auf diese Weise vielfach die ökologische Funktionalität der Gewässer prägen. Dabei trägt die vertikale oder horizontale Konnektivität zur Stabilisierung der beteiligten Ökosysteme bei, indem sie den Austausch ermöglicht von Pflanzennährstoffen, von Biomasse sowie von migrierenden Organismen, wodurch Phasen des Ressourcenmangels überbrückt werden.
Diese Ergebnisse können im Rahmen der Bewirtschaftung von Gewässern dahingehend genutzt werden, dass die Gewährleistung horizontaler und vertikaler Konnektivität in der Regel mit räumlich komplexeren, diverseren, zeitlich und strukturell resilienteren sowie leistungsfähi¬geren Ökosystemen einhergeht, die somit intensiver und sicherer nachhaltig genutzt werden können.
Die Nutzung einer kleinen Auswahl von Ökosystemleistungen der Flüsse und Seen durch den Menschen hat oftmals zu einer starken Reduktion der ökologischen Konnektivität, und in der Folge zu starken Verlusten bei anderen Ökosystemleistungen geführt. Die Ergebnisse der dargestellten Forschungen zeigen auch, dass die Entwicklung und Implementierung von Strategien zum integrierten Management von komplexen sozial-ökologischen Systemen wesentlich unterstützt werden kann, wenn die horizontale und vertikale Konnektivität gezielt entwickelt wird. / Surface waters are seen traditionally as closed ecosystems, and the recirculation of water and nutrients in the pelagic zone of lakes is cited as an example fort his. However, recently important linkages have been demonstrated between the pelagic zone on one side, and the benthic and the littoral zones, the terrestrial shore area and the catchment on the other side.
Therby, the horizontal and vertical connectivity of aquatic ecosystems has attracted intense scientific interest, and together with this the ecological functions of the bottom zone (benthic zone) and of the shore zone (littoral zone), too. From this newly described connectivity far-reaching consequences arise for our picture of the functionality of surface waters.
In this habilitation thesis a number of internal and external functional linkages are depicted in the horizontal and vertical spatial dimensions, as exemplified by running waters and lakes of the north-east German lowlands. The underlying studies mostly comprised both abiotic and biotic variables, and a broad range of topics, methods and studied surface waters. Thereby, experiments in the lab and the field, as well as quantitative field measurements were used to investigate ecological key processes as nutrient retention, carbon dynamics, extracellular enzyme activity, and resource transfer in food webs (using stabile isotope technique).
In respect to running waters this resulted in substantial insights into the effects of a hydromorphology exhibiting intense connectivity on aquatic biodiversity and benthic-pelagic coupling, which represents a key process for the retention of transported matter, and thus for the productivity of a river section.
The littoral zone of lakes has hardly been studied in Central Europe for several decades. Thus, the results on community structure, habitat preference and food web linkages of eulittoral macrozoobenthos enabled fundamentally new insights, which can directly be used within approaches for the ecological assessment of lake shores according to the EU Water Framework Directive.
Research results show that the development and implementation of strategies for an integrated management of complex social-ecological systems may be substantially underpinned by targeted development of horizontal and vertical connectivity.
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Identifying Calcium-Binding Sites and Predicting Disulfide ConnectivityDeng, Hai 06 August 2007 (has links)
Most questions in proteomics require complex answers. Yet graph theory, supervised learning, and statistical model have decomposed complex questions into simple questions with simple answers. The expertise in the field of protein study often address tasks that demand answers as complex as the questions. Such complex answers may consist of multiple factors that must be weighed against each other to arrive at a globally satisfactory and consistent solution to the question. In the prediction of calcium binding in proteins, we construct a global oxygen contact graph of a protein, then apply a graph algorithm to find oxygen clusters with the fixed size of four, finally employ a geometry algorithm to judge if the oxygen clusters are calcium-binding sites or not. Additionally, we can predict the locations of those sites. Furthermore, we construct a global oxygen contact graph including oxygen-bonded carbon atoms of a protein, then apply a graph algorithm to find local biggest oxygen clusters, finally design another geometric filter to exclude the non-calcium binding oxygen clusters. In addition, we apply observed chemical properties as a chemical filter to recognize some non-calcium binding oxygen clusters. In order to explore the characteristics of calcium-binding sites in proteins, we conduct a statistic survey on four datasets derived from 1994 to 2005 about the geometric parameters and chemical properties of calcium-binding sites. In the prediction of disulfide bond connectivity, we analyze protein sequences to predict the folding of proteins relative to the cystines using nearest neighboring methods. we extend a new pattern-wise method to all available template proteins, and find global pattern of pairing cysteines with a new descriptor of cysteine separation profile on protein secondary structure.
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Transformative power of creative process in learning : defining a path to relational connections with the environmentBlom, Monique R 24 August 2011 (has links)
This project offers an analysis of how the transformative power of creative process in learning offers humankind relational connections with the natural environment. It supports the recommendation that educational institutions move towards a transformative creative learning process. The paper argues that by teaching children through assumptions of the world as in constant creative becoming humankind will move toward
a more encompassing, coherent story of the universe which allows for the increasing self-actualization of individuals. After offering a theoretical discussion of the transformative power of creativity through the works of Brian Swimme, Edmund OSullivan and Alfred North Whitehead, the author provides descriptive, interpretive and critical narrative accounts of a teaching occasion created by her in which she illustrates her understanding of this transformative power.
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