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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Toxicity and mutagenicity of Upper Danube River sediments determined by chemical fractionation, the <i>Danio rerio</i> embryo assay, the Ames fluctuation test and the H295R assay.

Higley, Eric Bertram 18 November 2009 (has links)
Declines in some fish populations in the Upper Danube River, Germany, have been reported during the past decades despite extensive stocking efforts. Many theories exist for why such declines have occurred including habitat change, dams, invasive species, disease and pollution. One of the factors of concern in the Upper Danube River is pollution because a number of studies have shown that sediments collected from this area were acutely and/or chronically toxic to fish. Although it can be difficult to link bioassay results to direct effects on the population level, bioassays can give us insight into the potential of exposure of wildlife including fish to sediment. In combination with other researchers a large battery of sediment testing on the Upper Danube River is being performed. Testing includes sediment testing of estrogen receptor mediated processes, dioxin-like responses and genotoxic effects. In this study, four sediment extracts from the Upper Danube River in Germany were used with a novel fractionation technique to characterize the sediment extracts and fractions for their ability to disrupt steroidogenesis, for their mutagenic activities and their teratogenic effects. Fractionation of each of the four sediment samples was performed by separating compounds according to their polarity, planarity, and the size of the aromatic ring system in an on-line fractionation procedure on coupled high performance liquid chromatography columns.<p> Mutagenic activity was measured in the raw sediment extracts and all 18 fractions using the Ames fluctuation assay and the Danio rerio embryo assay was used to assess lethal endpoints. Furthermore, disruptions of steroidogenesis were assessed by first establishing methods and a proof of concept of the H295R assay by exposing H295R cells to 7 model chemicals and measuring changes from a control in estradiol, testosterone and aromatase activity. Once methods were established all sediments and their fractions were analyzed using the Assay.<p> Specifically, in the <i>Danio rerio</i> assay, two raw sediment extracts killed 100% of <i>Danio rerio</i> embryos at a concentration of 33.3 mg sediment equivalents (SEQ)/ml, but none of the 18 fractions of these samples produced any measured toxicity at a concentration of 100 mg SEQ/ml. In the Ames fluctuation assay, significant mutagenic activity was measured in raw sediment extracts and in the fractions. Fraction 10 produced a significant mutagenic response in all sediment samples measured only in S9 bio-activated samples. Furthermore, fraction 15 produced a significant mutagenic response in all sediment samples measured only in non bio-activated samples.<p> All raw extracts tested in the H295R assay caused an increase in estradiol production up to 4-fold from controls. Testosterone production increased slightly from controls in only two of the raw extract samples. Of the 18 fractions, fractions 7, 10 and 15 increased estradiol in at least three of the samples studied (Sigmaringen2006, Opfingen2006, Lauchert2006 and Lauchert2004). Furthermore, fraction 7 significantly decreased testosterone production compared to controls in three of the four sediment samples.<p> Taken as a whole, these results show the value of using multiple bioassays and fractionation to characterize sediments that covers a variety of different biological endpoints. This study also demonstrates the usefulness of the H295R assay when combined with a new fraction technique to assess endocrine disrupting chemicals in sediment samples.
22

NEOLITHIC SETTLEMENTS ON BALKAN : A comparative study between Durankulak and Sitagroi

Näslund, Christina January 2009 (has links)
This thesis examines the Neolithic settlements in Durankulak, Danube, north of Bulgaria and Sitagroi in Greek Macedonia at the time when human life went from nomadic and hunting to well organized, agriculture and settled. As a background I present facts about the chronology, I will look for similarities and differences in the climate and the environment of the settlements and then I make a comparison based on the material findings. The facts, analyses and artefacts give a base for understanding the daily life in Durankulak and Sitagroi. By comparing the settlements I will investigate if the Neolithization was a homogenous process on Balkan or if there are differences that indicate external inputs from several directions.
23

Black Sea Environmental Regime: Challenges And Opportunities

Istemil, Alara 01 July 2004 (has links) (PDF)
This thesis aims to analyze the Black Sea environmental regime, which consists of three main parts. The first part of the study, after a general introduction to the environmental aspect of international politics, puts forward the regime formation in the field of environment and the development of global and regional environmental policy and law for the protection of coastal and marine environments. The second part firstly describes the peculiar characteristics and the environmental problems of the Black Sea. Secondly, it analyzes the disintegrative and integrative motives behind the establishment of the regime. Lastly, the legal, institutional and financial framework of the regime together with the role of international donors in the Region are put forward. The third part identifies the challenges affecting the functioning of the regime as well as the opportunities for the future of the Black Sea. The main concern of this study is to have an insight of the Black Sea environmental regime to see whether the regime has been functioning sustainably to enable the protection of the Black Sea and the recovery of its ecosystem.
24

Lodní doprava na kanálu Rýn - Mohan - Dunaj / Shipping on the Rhine-Main-Danube-Canal

Charousková, Lucie January 2008 (has links)
This paper surveys the inland water transportation on the Rhine-Main-Danube-Canal. Beginning with a consideration of the inland water transportation in Europe in the analysis, it briefly describes the canal's evolution and fundamental terms, which are related to the water-ways. The last part of the first chapter is dedicated to the comparison of several traffic carriers. In the second chapter the two predecessors of the Rhine-Main-Danube-Canal and the motivations to their construction are reviewed. In the more detailed inspection of the formation of the RMD-Canal, the crucial institutions, which are involved in this domain, are described. Besides the corporation "Rhein-Main-Donau AG", the "Deutscher Wasserstraßen- und Schifffahrtsverein Rhein-Main-Donau e.V." and the "Wasser- und Schifffahrtsdirektion Süd" belong to it. The third part of the available paper analyzes the shipping on the RMD-Canal and on the German part of the Danube out of an economic-geographical perception. Regarded are not only differences in shipping on the Rhine, on the canal itself and on the Danube, but also the charges for using the canal and for the locking of ships. Moreover, the RMD-Canal is observed out of the traffic-geographical aspect, whilst also analysing the prognoses in comparison to the reality of the amount of shipping. The present time situation is illustrated by the example of the amount of cargo, which has been transported in the last years. At the end of the paper the problematic passage between Straubing and Vilshofen and the solution of the abolishment of this bottleneck is described.
25

Nákladní říční doprava na Dunaji v Rakousku / Cargo inland waterway transport on the Danube in Austria

Hrančík, Přemek January 2011 (has links)
The introductory part of this thesis focuses on the detailed characteristics of the Danube region, on the Danube itself as well as on the ongoing international cooperation of involved Danubian countries. Next section contains a comprehensive analysis of the cargo inland waterway transport on the Danube in Austria with respect to historical development, present state of commodity transportation as well as with respect to facilities and performance of Austrian ports and accessibility of the Danube for cargo river ships during the year. The final part of this thesis deals with current problems of cargo river carriers on the Austrian part of the Danube and there are possible solutions to these problems as well. Attention is also paid to the importance of cargo inland waterway transport for the whole country.
26

Využitelnost kanálu Dunaj - Odra - Labe pro říční dopravu v zemích střední Evropy / The possibility of usage of the Danube-Oder-Elbe canal for the river transportation within the countries of the central Europe

Zajíčková, Šárka January 2013 (has links)
This thesis analyses potential benefits of Danube-Oder-Elbe canal to the states of the central Europe. In order to do that it is necessary to describe the current importance of inland navigation within these states as well as the condition of the waterways. The main bottlenecks on existing infrastructure are the missing locks. The paper also looks into the development of support of the Danube-Oder-Elbe canal from the first reference in 1700 to the year of 2014. The last part of the work deals with the calculation of estimated direct costs and profits of the construction. Besides the direct there are also indirect expenses, which cover not only the necessary repairs and maintenance, but also external costs. External costs of inland water navigation are estimated to be six times lower than those of road transport. This difference could be a significant competitive advantage of the river transportation.
27

Геонаслеђе Средњег и Доњег Подунавља у Србији: инвентар, геоконзервација и геотуризам / Geonasleđe Srednjeg i Donjeg Podunavlja u Srbiji: inventar, geokonzervacija i geoturizam / Geoheritage of the Middle and Lower Danube in Serbia: inventory, geoconservation and geotourism

Tomić Nemanja 07 July 2016 (has links)
<p>Геотуризам представља релативно нов феномен у свету и често се помиње&nbsp;као туризам специјалних интересовања, који подржава и промовише објекте&nbsp;<br />природног али и културног наслеђа.&nbsp; На територији Подунавља у Србији налазе се&nbsp;<br />бројни геолошки и геоморфолошки облици као и палеонтолошки остаци мамута који &nbsp;представљају јединствено богатсво и као такви представљају идеалне ресурсе за развој туризма. У оквиру ове студије биће предложен инвентар геолокалитета овог &nbsp;простора са посебним освртом на мере геоконзервације.&nbsp; Један од главних циљева је такође и модификација постојећих и креирање нових метода за туристичко вредновање геолокалитета. Помоћу ових метода и&nbsp; уз анкетно истраживање, главни циљ јесте утврђивање&nbsp; најатрактивнијих подручја и&nbsp; геолокалитета за развој геотуризма Средњег и Доњег Подунавља у Србији&nbsp; као&nbsp;и утврђивање&nbsp; основних карактеристика и преференција потенцијалног тржишта&nbsp;геотуризма Србије.</p> / <p>Geoturizam predstavlja relativno nov fenomen u svetu i često se pominje&nbsp;kao turizam specijalnih interesovanja, koji podržava i promoviše objekte&nbsp;<br />prirodnog ali i kulturnog nasleđa.&nbsp; Na teritoriji Podunavlja u Srbiji nalaze se&nbsp;<br />brojni geološki i geomorfološki oblici kao i paleontološki ostaci mamuta koji &nbsp;predstavljaju jedinstveno bogatsvo i kao takvi predstavljaju idealne resurse za razvoj turizma. U okviru ove studije biće predložen inventar geolokaliteta ovog &nbsp;prostora sa posebnim osvrtom na mere geokonzervacije.&nbsp; Jedan od glavnih ciljeva je takođe i modifikacija postojećih i kreiranje novih metoda za turističko vrednovanje geolokaliteta. Pomoću ovih metoda i&nbsp; uz anketno istraživanje, glavni cilj jeste utvrđivanje&nbsp; najatraktivnijih područja i&nbsp; geolokaliteta za razvoj geoturizma Srednjeg i Donjeg Podunavlja u Srbiji&nbsp; kao&nbsp;i utvrđivanje&nbsp; osnovnih karakteristika i preferencija potencijalnog tržišta&nbsp;geoturizma Srbije.</p> / <p>Geotourism represents a relatively&nbsp; new phenomena in the world and it is often referred to as special interest tourism&nbsp; which enhances and promotes natural and cultural heritage.&nbsp; The Danube River territory in Serbia has many geological and geomorphological features and sites as well as paleontological remains of&nbsp; mammoths which represent unique values and as such, they are ideal for tourism development. This study will suggest an inventory of geosites in this area with a special focus on geoconservation measures. One of the main goals is also&nbsp; the modification of existing and the creation of new methods for geosite evaluation. By using these methods, along with a detailed survey research and analysis, the main&nbsp; goal is to determine the most attractive areas and geosites for geotourism development&nbsp; on the territory of the Middle and Lower Danube in Serbia and also to determine the&nbsp; basic characteristics and preferences of the potential geotourism market of Serbia</p>
28

Distribucija lipofilnih organskih polutanata u heterogenom multikomponentnom rečnom sistemu / Distribution of lipophilic organic pollutants in a river heterogeneous multicomponent system

Brborić Maja 02 October 2020 (has links)
<p>U doktorskoj disertaciji evaluirani su rezultati kvantifikovanih koncentracionih nivoa lipofilnih perzistentnih i emergentnih organskih polutanata u uzorcima sedimenta kolektovanih sa deset reprezentativnih lokaliteta u srednjem Podunavlju. Na osnovu sprovedenih laboratorijskih i terenskih istraživanja definisan je prostorni trend jedinjenja na ispitivanom području. Primenom multivarijantnih tehnika eksperimentalni rezultati su uspešno modelovani statističkim metodama koje su izdiferencirale izvore kontaminacije za ukupan set ispitivanih polutanata. Prikazana je procena uticaja kontaminiranog sedimenta na akvatične organizme i humanu populaciju prema stepenu kancerogenosti jedinjenja. Predstavljeni su različiti scenariji izloženosti ingestijom i dermalnim kontaktom, u zavisnosti od vremena ekspozicije i izložene površine potencijalnih receptora, različitog uzrasta i pola. Po prvi put u istraživanom području, implementirana je ex-situ ravnotežna metodologija pasivnog uzorkovanja primenom sorpcionog medijuma od silikonske gume testirane pri različitim masenim odnosima polimer-uzorak sedimenta. Primenjenom metodom uspešno su dobijene slobodno rastvorene koncentracije lipofilnh kontaminanata u pornoj vodi sedimenta, kao prediktora za određivanje biodostupnosti jedinjenja.</p> / <p>The doctoral dissertation evaluated the results of quantified concentration levels of lipophilic persistent and emergent organic pollutants in sediment samples collected from ten representative localities in the central Danube region. Based on the conducted laboratory and field research, the spatial distribution of compounds in the studied area was defined. Using multivariate techniques, the experimental results were successfully modeled by statistical methods that differentiated the sources of contamination for the total set of tested pollutants. A risk assessment of contaminated sediment on aquatic organisms and the human population according to carcinogenicity of the tested compounds is presented in thesis. Different exposure scenarios of ingestion and dermal contact, depending on the time exposure and exposed surface skin of potential receptors, of different ages and sex, are presented. For the first time in the study area, an ex-situ equilibrium passive sampling methodology was implemented using silicone rubber sorption medium tested at different polymer-sample sediment mass ratios. Using the method, the freely dissolved concentrations of lipophilic contaminants in pore water were successfully obtained as predictors for determining the bioavailability of the compounds.</p>
29

Une pratique sociale à l’épreuve de la conservation de la nature. Incertitudes et controverses environnementales autour de la dégradation de la pêche dans la Réserve de la Biosphère du Delta du Danube. / A social practice face to nature conservation policies : controversies and uncertainties around fish degradation and conservation practices in the Danube Delta Biosphere Reserve

Mitroi Tisseyre, Veronica 25 February 2013 (has links)
Cette thèse présente les mutations d’une pratique sociale qui repose sur l’interaction directe avec l’environnement – la pêche, dans l’espace du delta du Danube, territoire doté d’une remarquable richesse écologique et engagé, après 1990, dans une double transition socio-économique et écologique qui implique une redéfinition radicale des pratiques d’appropriation des ressources naturelles. Caractérisée par une multiplication des acteurs, des savoirs et des actions, la création d’une Réserve de Biosphère du Delta du Danube met à l’épreuve l’existence même de la pratique de pêche et l’interaction des habitants avec les ressources désormais « naturelles » du delta. A travers une analyse des dispositifs de réglementation des droits de pêche expérimentés dans la Réserve au cours des 20 dernières années, cette thèse présente la dégradation de la pêche comme un espace d'incertitude où les « êtres de la pêche » : acteurs sociaux et poissons, sont redéfinis, expliqués, apprivoisés, mobilisés dans la définition de nouvelles formes d'interaction entre les acteurs sociaux et des ressources naturelles. Dans un contexte de persistance des pratiques de pêche illégales, les indicateurs utilisés dans la formulation des droits de pêche ont une faible capacité à faire évoluer les pratiques. L'approche développée dans cette thèse est clairement confrontée à la manière dominante de penser et de faire dans les politiques de conservation, orientées vers une plus grande rationalisation et la formulation de chaînes logiques entre des indicateurs, des droits et des résultats attendus. Nous montrons les limites de cette approche, qui devrait avoir comme préoccupation première de dépasser la distinction entre « ceux qui savent » et « ceux qui pêchent », en facilitant l’émergence des accords collectifs sur la définition des acteurs, des ressources et de leur état écologique. Nous montrons que dans le monde de la pêche artisanale, la réussite des dispositifs de gestion de la pêche dépend de leur capacité à prendre en considération les savoirs, les pratiques et les capacités critiques des acteurs locaux, développés au cours d’une longue appropriation des ressources. / In the last two decades, different fishing rights systems have been experimented in the Danube Delta Biosphere Reserve fisheries in order to orient natural resources exploitation practices towards the conservation of biodiversity. Overfishing is considered as one of the main threats to conservation in this ecologically fragile area, since 1989, when the communist productivist model was replaced by conservationist policies. Characterized by the multiplication of actors and knowledge production, the creation of the Biosphere Reserve of Danube Delta is challenging the continuity of fishing practices. Based on an analysis of the fishing rights systems experienced in the reserve, this work presents the degradation of fisheries as an area of uncertainty where social actors and fishing resources are redefined, explained, tamed and mobilized in the definition of new forms of ecological interactions between actors and resources. Indicators and proofs of sustainable fisheries are built on the ground, while experimenting different fishing rights systems. In a context of persisting illegal fishing practices and persistent controversies, fishing rights do not legitimate the introduction of more restrictive measures, and have a week capacity of changing practices. The approach developed in this thesis tries to go beyond the classical distinction between knowledge producers and nature users, by considering knowledge production, rights definition and social practices over nature as interconnected elements of the same process of nature appropriation. The perspective developed in this work is clearly confronted to the dominant way of thinking and doing in conservation policies, oriented towards a greater rationalization and the pre-formulation of a logical chain between measures, effects and outcomes. We show the limits of this approach, which should be primarily concerned by overcoming the distinction between "those who know" and "those who fish", facilitating the emergence of collective agreements on the definition of resources and their ecological status. We show that in the world of artisanal fisheries, the success of fisheries management incentives depends on their ability to take into account the diversity of knowledge, practices and critical capacities that local actors developed through resources appropriation practices.
30

Les eaux du delta du Danube : approche géographique par télédétection satellitaire / Geographical approach of Danube Delta waters through satellite remote sensing

Güttler, Fábio Nór 10 December 2012 (has links)
Classiquement étudié par différentes disciplines scientifiques, le domaine de l'eau est au cœur des préoccupations environnementales contemporaines. En Europe, l'évaluation et le suivi de l'état écologique des "masses d'eau" sont désormais exigés par la législation communautaire, la directive cadre sur l'eau (DCE - 2000/60/CE) fixant des objectifs pour leur préservation ou leur restauration le cas échéant. Dans ce contexte, des expériences d'utilisation de l'imagerie satellitaire en appui au suivi écologique des eaux se sont succédées en Europe, notamment pour les masses d'eau côtières et pour les grands lacs. Malgré cela, la précision spatiale de l'imagerie utilisée pour ce type de suivi ne permet pas l'observation fine de secteurs littoraux très proches de la côte ou de lacs avec une surface réduite (par ex. inférieure à 5 km²). Pour ces espaces aquatiques particuliers, pourtant très nombreux, l'utilisation de la télédétection satellitaire est moins sollicitée. Cette recherche doctorale a été réalisée sur une zone littorale réunissant plusieurs de ces espaces aquatiques peu investigués par la télédétection satellitaire. Situé à la frontière orientale de l'Europe et à distance égale du pôle nord et de la ligne de l'équateur, le delta du Danube, en tant qu'espace naturel remarquable, bénéficie de différents statuts de protection (réserve de biosphère, site RAMSAR, patrimoine mondial naturel de l'UNESCO). Ceux-ci s'expliquent en grande partie par la forte diversité d'espaces aquatiques aussi bien sur la plaine deltaïque que sur la zone côtière adjacente (bras de fleuve, chenaux, lacs, baies, golfes, marais, îles-barrières). Ce continuum hétérogène, constituant l'hydrosystème du delta du Danube, et son prolongement en mer côtière, sont l'objet principal de ce doctorat. La notion d'échelle occupe une place centrale dans notre démarche d'analyse puisque l'on est à l'intersection de deux grands systèmes (le bassin versant du Danube et la mer Noire) dont les étendues sont de deux ordres de grandeurs plus vastes que celle du delta ; la dimension temporelle est aussi fondamentale dans la mesure où les processus de morphogénèse et de remaniement (naturels et anthropiques) se font fortement ressentir et se traduisent par une mobilité importante des formes de relief ainsi que des éléments de l'hydrographie deltaïque. Au delà des évolutions sur le moyen et long terme, la variabilité spatio-temporelle contemporaine des eaux au pas de temps intra-annuel (saisonnier et intra-saisonnier), jusque-là peu étudiée, a également été appréhendée dans cette thèse. Par son côté exploratoire, la mise en place d'une chaîne de traitements d'images satellitaires adaptée à l'étude des eaux deltaïques représente, en soi, l'objectif méthodologique principal de ce doctorat. Dans cette voie, différents lots d'images ont été mobilisés : en fonction des fluctuations du niveau d'eau du Danube, nous avons retenu la période 2006-2009, étudiée à travers un total de 85 images satellitaires, dont 52 à moyenne résolution spatiale (MERIS) et 33 à haute résolution spatiale (ALOS AVNIR-2, SPOT HRVIR, Landsat TM et ETM+) ; à ce premier lot s'ajoute une soixantaine de prises de vue "historiques" couvrant la période comprise entre 1972 et 2005 (capteurs de la série Landsat MSS, TM et ETM+), ainsi que, pour la période plus récente, cinq images Landsat TM de 2010 et 2011. Trois procédés distincts mais complémentaires ont été mis en œuvre pour traiter cet ensemble hétérogène d'images. L'analyse intégrée des résultats obtenus avec des données hydrologiques et météo-océanographiques nous a permis d'apporter des nouveaux éléments de compréhension sur le fonctionnement actuel et passé du delta du Danube. / The Danube River and its contributors cross nineteen European countries before reaching the West coast of the Black Sea. In the context of the Black Sea drainage basin, the Danube River is the most important source of liquid and solid discharges. The fluvial-marine contact zone is quite large because Danube splits up itself into multiple distributaries across a wide deltaic plain (4,142 km²) shared among Romania and Ukraine. Vast areas of compact reedbeds usually surround the three hundred freshwater lakes of the delta. Many of these shallow lakes are connected to channels or canals providing turbid water from the Danube, while others depend on flood events to be supplied by the turbid waters coming from the river. Important seasonal growth of floating and submerged macrophytes also occurs in the majority of the lakes. Thus, Danube Delta presents a complex hydrosystem which has been greatly modified since the first navigation works in the nineteenth century. Since the beginning of the nineties, the Danube Delta became a Biosphere Reserve (MAB-UNESCO), a RAMSAR site and was included on the list of the World Natural Heritage (UNESCO). Analyzing spatial patterns in complex environments, like Danube Delta and its coastal zone, requires non traditional approaches. Remote sensing multi-sensor techniques offer reliable advantages to observe and understand intricate processes operating on different space-time scales and especially in large areas with difficult and sometimes restricted access (e.g. Biosphere Reserve core areas). The main methodological objective of this thesis was to create a procedure for processing heterogeneous optical satellite images. By studying the Danube Delta area (hydrosystems principally) through different space-time scales, we worked with several types of high and moderate spatial resolution images. Based on Danube water levels, we analyzed 85 satellite images from the period 2006-2009 (52 medium resolution images - MERIS and 33 high resolution images - ALOS AVNIR-2, SPOT HVIR, Landsat TM / ETM+). This main satellite data set was completed with more than sixty "historical" images (1972-2005) acquired with the Landsat sensors (MSS, TM and ETM+). Three distinct, but complementary, approaches were used to process the satellite images. The integrated analysis of the satellite results with hydrological and meteo-oceanographical data series enabled us to bring new elements of explanation about the past and present dynamics of Danube Delta.

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