A multi-proxy paleoecological study that included pollen, microfossil, carbon (C), and nitrogen (N) analyses was conducted at a central Vancouver Island wetland near Courtenay British Columbia to reconstruct the site’s history, C and N accumulation rates, and surrounding vegetation over the last 14,000 years. The paleoecological record shows that the lake that occupies the southeast corner of the wetland today was much larger during the late glacial period. Peat accumulation began through terrestrialization of the site, leading to vegetation and edaphic conditions characteristic of a bog or fen with variable water table depth inferred from testate amoebae and other microfossil remains. C accumulated with maximum and time-weighted mean accumulation rates of 81 and 19 g C/m2/cal yr, respectively. The highest C accumulation occurred during the accumulation of herbaceous peat in the early Holocene, which, given the similarity to other Northern Hemisphere peatlands, suggests a strong climate forcing of C accumulation. N accumulated with a time-weighted mean of 0.55 g N/m2/cal yr. Forest community composition was also affected by the changing climate. Pinus contorta dominated open forests near the site between at least 13,900 and 11,200 cal yr BP. Picea and Abies increased during Younger Dryas cooling (12,900-11,700 cal yr BP). Pseudotsuga menziesii was the most abundant tree species in the area during the early Holocene (11,200-7500 cal yr BP). Around 7000 cal yr BP there was a shift to Tsuga heterophylla dominated forest, which continues to the present. This multi-proxy 14,000-year record provides evidence of the importance of climate and local factors in bog development, C and N accumulation, and vegetation history since the last glaciation. / Graduate / 2019-04-12

Abstract This thesis deals with the Holocene development of palsa mires in continental Europe, especially permafrost dynamics and its consequences on vegetation succession and peat accumulation. Peat deposits of four permafrost mires in boreal and subarctic northeastern European Russia and in northern oroboreal Finland have been studied using plant macrofossil analysis, (AMS) radiocarbon dating, dry bulk density and carbon content measurements. In addition, preliminary results are available from another palsa mire in northeastern European Russia. Modern vegetation has been investigated to support the interpretation of fossil plant assemblages. Earlier literature on vegetation, stratigraphy and dating of permafrost mires in Europe has been reviewed. The vegetation of palsa mires in general is well known. As a rule, palsas are dry ombrotrophic habitats, surrounded by wet flarks of variable trophic levels. There is a lack of information about vegetation in different small-scale habitats within palsa mires, which would have been useful when studying the permafrost-vegetation relationship. Although no functional indicator species of permafrost have been found, permafrost dynamics in peat stratigraphy can often be detected with high degree of probability based on changes in vegetation. Some plant assemblages and vegetation successions are typical on permafrost, while many species rarely grow on or near to permafrost. Relatively sudden changes between dry and wet mire environments and continuously dynamic conditions are good signs of permafrost impact. Also gradual changes towards drier conditions may be caused by permafrost; in these cases the timing of first permafrost aggradation is more difficult to ascertain and can usually be pronounced only in terms of maximum and minimum ages. Changes in peat accumulation rates and even hiatuses in stratigraphy are additional tools to support the interpretation on permafrost history at the studied sites. Dry organic matter and carbon accumulation rates for different developmental stages are calculated for the five studied mires. From earlier studies this information is not available. Accumulation rates in the permafrost environment are very variable: from zero or negative rates in old palsas to as high as 100 gC/m2yr in incipient palsas. On moist plateau palsas, permafrost flarks and in unstable permafrost conditions, accumulation continues at low to moderate rates. Thermokarst processes result in decomposition of former peat deposits with important consequences for the ecosystem carbon balance, especially in plateau palsa mires. Radiocarbon datings are available from 27 permafrost mires in continental Europe; only 5 of these are situated in Russia. Many of the published dates cannot be considered reliable as dating permafrost aggradation. Based on limited material, permafrost started to develop at latest about 3000 BP in mires of northern Russia and 2500 BP in Fennoscandia. Older permafrost formation is suggested for a few sites, but the evidence is insufficient to confirm this interpretation. The oldest preserved palsas are ca. 2500–2000 14C years old. Most of the modern palsas are less than 600 14C years old. Permafrost aggradation follows the major climate development in the Holocene, with formation being most active during the coldest stages. Global warming is expected to greatly affect the Arctic in the near future, which would imply significant changes in ecosystem functioning and carbon balance of permafrost mires. This study contributes to the understanding of the possible impacts of climate change on these ecosystems using paleoecological techniques.

Abstract The overall aim of this Thesis is to emphasise how Ground Penetrating Radar (GPR) can be used in different glaciological studies: in mapping the inner structure, determining accumulation rates, estimating water contents, mapping drainage channels and superimposed ice. The Thesis also aims to improve current knowledge on Svalbard polythermal glaciers: their hydrothermal properties, drainage and behaviour in the changing climate. Six glaciers were studied: four tidewater glaciers, one ice-field and one valley glacier. The hydrothermal structure of Hansbreen was mapped with GPR at high lateral and vertical resolution. The hydrothermal structure of the glacier is highly variable and complex. In general the temperate ice contains 1-2% water, but water contents of about 4% are associated with englacial water channels or water-filled near surface crevasses or moulins. Hydrothermal properties determined from detailed GPR surveys of Hansbreen, Werenskioldbreen, Nordenskjöldbreen and Kongsvegen show similar structures such as foliations and superimposed ice in the firn-ice transition area, though with different emphasis on each glacier. The overall extent of superimposed ice was difficult to measure accurately because of the limited resolution and the sporadic nature of the reflections. However there is encouraging similarity between GPR and satellite imagery of superimposed ice extent. Hydraulic geometry models of the subglacial hydrology of Hansbreen and Werenskioldbreen suggest that the water pressure is generally close to ice-overburden pressure but varies greatly depending on local conditions. GPR data and data from three ice-cores were used to determine spatial and temporal variation of snow accumulation on a longitudinal profile of Nordenskjöldbreen. Spatial variations of 40-60% in snow accumulation over short distances along the profile were observed. The results indicate a 12% increase in accumulation rate during the late 1980s and 1990s. Hornbreen and Hambergbreen and several surrounding glaciers in southern Svalbard were mapped with GPR together with a DGPS (Differential Global Positioning System) in 2000. The data were compared to glacier surface height and glacier front length data from 1936 and 1901. The results show that the low-lying glaciated valley filled with Hornbreen and Hambergbreen may become a partially inundated ice-free isthmus within the next 100-150 years.

Philosophiae Doctor - PhD / The general image of large-scale commercial farming in South Africa is one of technological dynamism and international competitiveness. However, such a generalisation obscures considerable differentiation in terms of size, scale, capital reproduction strategies and future directions of change between and within farming regions. My study on reproduction, accumulation and differentiation in the large-scale commercial farming sector makes a small contribution towards explaining this substantive diversity, as well as the underlying processes at work, in three different agro-ecological regions of the country. A framework to analyse the strategies of large-scale commercial farmers was derived from volume 1 of Marx’s Capital and interpretations thereof by Marxist scholars, e.g. Ernest Mandel, Henry Bernstein, David Harvey, Ben Fine and Alfredo Saad-Filho. The four strategies or processes are broadly identified as a) expanding the scale or scope of production, in other words, to increase the capital intensity of production and/or geographic size, and/or the number of products, b) expanding the scale or scope of the business by expanding into new enterprises either up or down the value chain, c) increasing economic efficiency, which can be achieved by means of lowering the cost of commodity production, increasing productivity in terms of yield per hectare or per animal through technical and biological efficiency, or by organising workers and tasks to make workers as productive as possible, and d) taking part in political action in order to reduce uncertainties and/or establish preferential access to and control over key resources, markets or policy processes. Data from a questionnaire survey conducted with 141 large-scale commercial farmers in Limpopo, the Western Cape and Northern Cape provinces, as well as semi-structured interviews with 32 farmers in these regions were analysed to determine the most prevalent strategies and assess their outcomes. The outcomes of these strategies varied between and within regions and resulted in the differentiation of capitalist farmers into “accumulators”, “successful reproducers”, “struggling reproducers” and “simple commodity producers”. This approach helps to uncover processes and patterns of agrarian change, and provides a richer, more detailed, understanding of the dynamics of change in the large-scale farming sector of South Africa which can help inform debates on policy optionsfor the sector and for land reform.

Accumulation and toxicity of cadmium, lead and thallium in duckweed (Lemna minor L.) The toxicity and accumulation of lead, cadmium and thallium in the aquatic plant Lemna minor was investigated, using a modification of the Organisation for Economic Co-operation and Development (OECD) standard growth inhibition test. Plants were cultured in modified Swedish Institute Standard (SIS) at pH 6.5±0.5 under 85 µmol m-2 S-1 at 25°C and exposed to a wide range of lead, cadmium, and thallium concentrations from environmentally realistic to very high concentrations (0.001, 0.01,0.1, 1, 10, 100, 1000 and 10 000 µmol L-1) for seven days. Various physico-biochemical endpoints were measured after seven days of exposure. The concentrations of dissolved lead, cadmium, and thallium remaining in the residual solutions, and accumulation of lead, cadmium and thallium in fronds and roots were assessed using Inductively Couple Plasma – Mass Spectroscopy (ICP-MS). Over the exposure duration, lead, cadmium, and thallium concentrations in solution decreased rapidly and chlorosis was observed in fronds exposed to the three highest lead, cadmium, and thallium concentrations. After seven days of exposure, there were significant decreases in the relative growth rate (RGR), relative frond area (RFA), pigment content (chlorophyll a, b and total carotenoid) and activity of photosystem II (Fv/Fm) at concentrations of 0.1, 1, 10, 100, 1000 and 10 000 µmol L-1Pb, 10, 100, 1000 and 10 000 µmol L-1cd, 0.01,0.1, 1, 10, 100, 1000 and 10 000 µmol L-1TI. However, our results suggested that root elongation based on relative growth rate of L. minor will be an optimal and relevant endpoint in compare to other endpoints. As expected, results demonstrated that root elongation was concluded that root length was most predictive of a dose response model compared to the rest of growth endpoints and physiological and biochemical endpoints when assessing toxicity of lead, cadmium and thallium using L. minor. Toxicity testing for the floating macrophytes should include root elongation measurement which alone will be sufficient to meet sensitivity and variability requirements for toxicity testing. Cellular concentrations of lead, cadmium, and thallium were higher in roots than fronds, whereas more lead, cadmium, and thallium was adsorbed to the extracellular matrix of fronds than roots. The bio - concentration factor (BCF; i.e. lead concentration in plant tissue at day seven relative to residual lead concentration in the growth medium at day seven) indicates that L. minor is a good accumulator of lead, cadmium, and thallium particularly at lower concentration, but the physiological data shows that these metals toxic at concentrations that can be encountered in wastewater treatment facilities. The translocation factor (TF) value was found to be less than 1. Though, lead, cadmium and Thallium was mostly stored in roots, only minor amounts of lead, cadmium and thallium were trans located to fronds.

This thesis examines the corporate appropriation of human right to water and sanitation discourse. David Harvey’s concept of accumulation by dispossession provides the political- economic basis for this analysis while enabling a discussion of water conflicts that looks at neoliberalization strategies beyond the privatization of services. Inspired by Gramsci’s notion of a “war of position”, this thesis investigates the role of corporate appropriation of human right to water and sanitation discourse in legitimating strategies of accumulation by dispossession. Through content and critical discourse analysis of publications of a corporate policy consortium called the 2030 Water Resources Group the investigation concludes that this lobby group simultaneously undermines human rights while actively using key elements of rights discourse to advance its neoliberal water policy objectives.

Submitted by Irene Nascimento (irene.kessia@ufpe.br) on 2016-04-15T15:44:21Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) DEFESA final.pdf: 1491112 bytes, checksum: 89527843dec44e6b139fde377f1bfe4e (MD5) / Made available in DSpace on 2016-04-15T15:44:21Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) DEFESA final.pdf: 1491112 bytes, checksum: 89527843dec44e6b139fde377f1bfe4e (MD5) Previous issue date: 2015-08-31 / CNPQ / A biomonitoração do ar pode utilizar organismos que têm estreita relação ecofisiológica com a atmosfera e alto grau de acumulação de elementos estáveis e/ou instáveis. Dentro deste tema, as plantas epífitas têm sido amplamente utilizadas como biomonitores, sendo consideradas ferramentas eficientes na avaliação de deposição atmosférica. Contudo, não se tem estudos que evidenciem a eficiência de acumulação de 210Pb na espécie T. recurvata L. Com base nisto, o presente trabalho avaliou a aplicabilidade da Tilandsia recurvata L. para determinação do 210Pb, investigando o potencial de acumulação deste biomonitor em condições laboratoriais e quando exposto em uma região com níveis de radioatividade natural significativos, como é o caso da região de Paulista e Igarassu. Estes municípios estão inseridos na região urano-fosfática do Nordeste brasileiro. As espécies de T. recurvata L. foram coletadas, tratadas e acondicionadas em bolsas de náilon e separadas, posteriormente, para a realização dos dois experimentos. O experimento em laboratório consistiu na avaliação do potencial de acumulação de 210Pb pela T. recurvata L., onde os biomonitores foram acondicionados em recipientes com cúpula transparente e levados à casa de vegetação, e sob condições naturais foram submetidos a níveis controlados de exposição ao radionuclídeo em questão. O outro experimento baseou-se na instalação das espécies em pontos selecionados para monitoração em campo, nos municípios de Paulista e Igarassu. Após o término de exposição, as amostras foram secas em estufa, maceradas, dissolvidas e levadas às análises radioquímicas para determinação de 210Pb. A concentração de atividade de 210Pb para cada amostra foi medida em um detector proporcional de fluxo gasoso. Os resultados obtidos com este trabalho confirmam a importância da espécie Tillandsia recurvata L. como ferramenta para o estudo da biomonitoração do 210Pb, por apresentar respostas mensuráveis, configurando-se a eficácia dessa espécie como bioparâmetro de análise para o diagnóstico de 210Pb atmosférico, além de ser o primeiro resultado de biomonitoração ativa da dispersão de 210Pb, em condições laboratoriais e nas regiões de monitoração. / The air biomonitoring can be carried out using organisms having a close relation ecophysiologic with the atmosphere and a high degree of accumulation of stable and / or unstable elements. Within this theme, the epiphytic plants have been widely used as biomonitors, considering efficient tools in the evaluation of atmospheric deposition. However, do not have studies that show the 210Pb accumulation efficiency in the species T. recurvata L. Based on this, the present study evaluated the applicability of Tilandsia recurvata L. for determining the 210Pb, investigating the potential to accumulate in this biomonitor conditions laboratory and when exposed in a region with significant levels of natural radioactivity, as is the case of Sao Paulo and Igarassu region. These municipalities and are inserted into furan-phosphate region of Northeast Brazil.The T. recurvata L. species were collected, processed and packed in nylon bags and separated later to carry out the two experiments. The laboratory experiment was to evaluate 210Pb accumulation potential by T. recurvata L. where biomonitors were acondicion in containers with transparent dome and taken to a greenhouse and under natural conditions were subjected to controlled levels of exposure to radionuclide in question. The other experiment was based on the installation of samples at selected points for field monitoring in the municipalities of São Paulo and Igarassu. After the end of exposure, the samples were oven dried, macerated, dissolved and brought to radiochemical analysis for determination of 210Pb. The concentration of 210Pb activity for each sample was measured in a gas flow proportional detector. The results of this study confirm the importance of the species Tillandsia recurvata L. as a tool for the study of biomonitoring of 210Pb, by presenting measurable responses, setting the efficacy of these species as bioparameter analysis for diagnosis of atmospheric 210Pb, and be the result of the first active biomonitoring of 210Pb dispersion in laboratory conditions and in the monitoring regions.

>Magister Scientiae - MSc / IP multicast is an efficient mechanism for simultaneously transmitting bulk data to multiple receivers. Many applications can benefit from multicast, such as audio and videoconferencing, multi-player games, multimedia broadcasting, distance education, and data replication. For either technical or policy reasons, IP multicast still has not yet been deployed in today’s Internet. Congestion is one of the most important issues impeding the development and deployment of IP multicast and multicast applications.

This thesis describes wind power plants with focus on specific type of power plant. The trends of wind turbines in the world and in the Czech Republic are briefly described. Part of the thesis is the calculation of wind power plants, according to the selected type, which is located in the site of Prosiměřice in Znojmo. Calculation using RETScreen programme was also used.

The aim of the thesis to explain the functionality of seasonal accumulation with an in-depth view on rock bed accumulator. The computational model is based on the project located in Attenkirchen, Germany. After the technical analysis of the model is carried out an economical review can be realized. To conclude the thesis an evaluation is made comparing an accumulation system with a more traditional one.