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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.
321

Changes in condition of herring (<em>Clupea harengus</em>) in Swedish coastal waters

Persson, Martin January 2010 (has links)
<p>The condition of the herring (<em>Clupea harengus</em>) in the Baltic Sea has decreased during the past 30-40 years. This decrease could be explained by different factors; (1) change in diet due to changes in zooplankton community, (2) changes in water temperature and salinity, (3) increasing nutrient inputs and (4) competition for food with other species such as sprat (<em>Sprattus sprattus</em>). In this study the change in condition was analysed using the Fulton’s condition index, and by looking at age and sex of the fish as well as the season and locationthe fish was caught, the differences between these factors were presented. Data from the national Swedish contaminant monitoring programme where used from four locations in the Baltic Sea and two locations at the Swedish West coast. The data was analysed using multiple regressions in R Commander. The result show that the condition, and the temporal trends in condition value, varies at different locations, with higher condition values and increasing temporal trends at the Swedish West coast, compared to the Baltic Sea with lower condition values and where three of four locations show decreasing temporal trends. The condition varied between spring and autumn caught herring as well, while age and sex showed less significant differences.</p>
322

Effects of some Endocrine Disruptors on Human and Grey Seal Uterine Cells

Bredhult, Carolina January 2007 (has links)
<p>The effects of environmental contaminants in humans and animals are of great concern. Some contaminants are endocrine disruptors that may interfere with the endogenous hormonal signalling and disturb, for example, reproductive organs and functions.</p><p>Primary uterine myometrial cells originating from women and Baltic grey seals were exposed to some polychlorinated biphenyls (PCBs) and their metabolites. Even though human and Baltic grey seal myometrial cells responded differently to the tested PCBs, the results indicate that PCBs can influence myometrial cell proliferation <i>in vitro</i>.</p><p>The prevalence of uterine leiomyomas was investigated among 257 Baltic grey seals. Leiomyomas were only present in females older than 22 years, at a prevalence of 65%. Proliferation in leiomyoma cells was detected in individuals lacking ovarian proliferation support, suggesting the presence of an exogenous stimulant. By taking into account temporal alterations in the contaminant burden of the seals, PCB exposure was found to be associated with leiomyoma prevalence. In conclusion, PCB exposure may be related to uterine leiomyoma development and proliferation in Baltic grey seals <i>in vivo</i>.</p><p>Human endometrial endothelial cells (HEECs) were exposed to some endocrine disruptors, and the effects of the endocrine disruptors on cell proliferation and viability were studied. All evaluated endocrine disruptors decreased HEEC proliferation and most also decreased HEEC viability. Further studies revealed that the reduction in HEEC proliferation after exposure to o,p’-DDT was associated with differential expression of mRNA involved in proliferation, defence response, and lipid and cholesterol metabolism compared to untreated HEEC. </p><p>In conclusion, these studies suggest that endocrine disruptors affect cultured cells from the female reproductive tract of humans and grey seals, and may have deleterious effects on proliferation, viability, and genes involved in defence response, and lipid or cholesterol metabolism.</p>
323

Brominated natural products at different trophic levels in the Baltic Sea : Identification of polybrominated dioxins, hydroxylated and methoxylated diphenyl ethers

Malmvärn, Anna January 2007 (has links)
Over time, the Baltic Sea has been contaminated by increasing discharges of pollutants from human activities. Persistent organic pollutants (POPs) have caused toxic effects in wildlife and excess of nutrients have led to eutrophication. Furthermore, there are indications that certain polyhalogenated compounds similar in structure to man-made POPs are produced by the biota present in this sea. In the late 1990’s both methoxylated polybrominated diphenyl ethers (MeO-PBDEs) and hydroxylated-PBDEs (OH-PBDEs) were identified in fish and seals living in this environment. OH-PBDEs can originate from metabolism of PBDEs, but both OH- and MeO-PBDEs are also known to be natural products in marine environments. Another group of POPs, the polybrominated dibenzo-p-dioxins (PBDDs), are not produced commercially, but are known to be by-products of chemical industry and of the combustion of, e.g., brominated flame retardants (BFRs). In contrast to the OH- and MeO-PBDEs, PBDDs have not previously been shown to be natural products, although certain related compounds have been indicated to have a natural origin. This thesis describes the identification of PBDDs, OH-PBDEs and MeO-PBDEs in algae, blue mussels and fish living in the Baltic Sea. Several of these compounds were also detected in cyanobacteria. Moreover, PBDDs were present in fish, mussels, shrimp and crabs from different regions of the Baltic Sea and from the west coast of Sweden, but not in organisms from freshwater environments. The levels of these compounds in Baltic fish generally exceeded those of their chlorinated analogues. The origin of the PBDDs identified is somewhat unclear, but the high levels present in blue mussels and the pattern of congeners observed indicate natural production. The presence of PBDDs, OH-PBDEs and MeO-PBDEs in fish and shellfish constitutes a potential risk to both humans and wildlife and requires further investigation.
324

Politique étrangère francaise en mer Baltique (1871-1914) : De l'exclusion à l'affirmation / French foreign policy in the Baltic sea area (1871-1914) : From exclusion to assertion

Fraudet, Xavier January 2005 (has links)
This thesis is a contribution to the study of French foreign policy in the time of “old diplomacy” in Northern Europe. Aiming to fill a gap, the object of investigation is French foreign policy in the Baltic area between 1871 and 1914 (from the French defeat during the Franco-Prussian War to the outbreak of the First World War). Particular attention is directed at the assets of the French diplomacy at work in the Baltic Sea: naval military planning, financial loans and culture. Since the period was dominated by the diplomatic isolation that Bismarck had placed France with the aim to prevent her from creating any kind of alliance to embark in a war of revenge against Germany, France carried out a policy of making ententes and alliances in order to break out from this isolation. However, in her attempt to emerge, France was challenged by Germany especially in relations with Denmark and Sweden. Although French foreign policy was able to use the loan as an instrument to secure a success with Russia by establishing a military treaty in 1892, but France did not succeed to attract and influence Sweden in the same way because of the risk of her turning to Germany. Also strongly challenged by Germany in Denmark, French foreign policy could not stop the willingness of Denmark to adopt a policy of neutrality. But, because of her intervention between Russia and Great Britain in the Dogger Bank incident in 1904, French diplomacy succeeded to gain the support of the British fleet in the case of a naval war in the Baltic Sea for operations against the German coast. Bringing together Russia and Great Britain for a naval cooperation in the case of a war in the Baltic Sea was, without any doubt, not only the most audacious and difficult task for French foreign policy, but also a sign of its strong revival. However, this Russo-British naval cooperation could not be converted into practice because of the geographical specificities of the Baltic Sea and the difficulties of naval military planning. Adressing this aspect, this thesis reveals the fundamental mistakes of the naval theoreticians who were defending naval theories based on land military theories and experiences.
325

Effects of some Endocrine Disruptors on Human and Grey Seal Uterine Cells

Bredhult, Carolina January 2007 (has links)
The effects of environmental contaminants in humans and animals are of great concern. Some contaminants are endocrine disruptors that may interfere with the endogenous hormonal signalling and disturb, for example, reproductive organs and functions. Primary uterine myometrial cells originating from women and Baltic grey seals were exposed to some polychlorinated biphenyls (PCBs) and their metabolites. Even though human and Baltic grey seal myometrial cells responded differently to the tested PCBs, the results indicate that PCBs can influence myometrial cell proliferation in vitro. The prevalence of uterine leiomyomas was investigated among 257 Baltic grey seals. Leiomyomas were only present in females older than 22 years, at a prevalence of 65%. Proliferation in leiomyoma cells was detected in individuals lacking ovarian proliferation support, suggesting the presence of an exogenous stimulant. By taking into account temporal alterations in the contaminant burden of the seals, PCB exposure was found to be associated with leiomyoma prevalence. In conclusion, PCB exposure may be related to uterine leiomyoma development and proliferation in Baltic grey seals in vivo. Human endometrial endothelial cells (HEECs) were exposed to some endocrine disruptors, and the effects of the endocrine disruptors on cell proliferation and viability were studied. All evaluated endocrine disruptors decreased HEEC proliferation and most also decreased HEEC viability. Further studies revealed that the reduction in HEEC proliferation after exposure to o,p’-DDT was associated with differential expression of mRNA involved in proliferation, defence response, and lipid and cholesterol metabolism compared to untreated HEEC. In conclusion, these studies suggest that endocrine disruptors affect cultured cells from the female reproductive tract of humans and grey seals, and may have deleterious effects on proliferation, viability, and genes involved in defence response, and lipid or cholesterol metabolism.
326

Nitrogen land-sea fluxes in the Baltic Sea catchment : Empirical relationships and budgets

Eriksson Hägg, Hanna January 2010 (has links)
In this thesis empirical relationships and modeling tools are used to describe the relationship between human activities and meso- and large scale riverine N fluxes from land to sea. On a large scale Paper I showed that by only having knowledge about human population size and runoff one can estimate the riverine export of DIN (r2= 0.76). In Paper II we included two other important anthropogenic N inputs, i.e. atmospheric deposition and primary emission (PE) from animals. In most of the catchments the PE from animals were larger than the PE from humans. Hence, development of livestock is important and increased animal protein consumption by humans might increase the riverine N export. Scenario analysis (Paper II) show that climate change is expected to both decrease and increase the riverine N export depending on which part of the catchment is modeled. In the southern and eastern parts of the Baltic Sea catchment there is large potential for N reductions from point sources (Papers III &amp; V). The diffuse sources are more difficult to decrease and a reduction of mineral fertilizer does not always lead to reduced N loadings because the agricultural systems can buffer even a slight surplus (Paper III). There is inertia in the catchments which can be seen in for example in the northern part of the catchment. Here atmospheric N deposition is almost as high as in the southern part but the nitrogen flux from these rivers is not elevated. These northern river catchments have N exports of the same magnitude as the natural background (Paper IV), indicating that the atmospheric N deposition is retained in the system and probably taken up by N limited boreal forests. However, important reductions can be achieved in the agricultural sector by detailed management of the planted land and animal manure. The highest sensitivity is in catchments with high animal density and high specific discharge, primarily draining to Kattegat and Danish Straits (Paper II &amp; IV). / At the time of doctoral dissertation the following publications were unpublished and had a status as follows: Paper 2: Manuscript. Paper 4: Manuscript
327

Determinants of Swedish and German FDI : The case of Baltic and CEE Countries

Cociu, Sergiu, Gustavsson, Thomas January 2007 (has links)
This thesis tries to determine some of the driving force behind Swedish foreign direct in-vestments into the Baltic counties. The analysis is performed in three steps, first we analyze global FDI into transitional economies, and afterwards we look at Swedish FDI and com-pare it with German FDI. The determinants examined are index of economic freedom, R&amp;D intensity, trade balance, wage level and proximity. The analyzed period is form 1995 to 2005. The analysis use data on the following transition countries Latvia, Lithuania, Esto-nia, Poland, Hungary, Czech Republic, Slovak Republic, Slovenia, Croatia, Romania and Bulgaria. The results show that the determinants vary across the countries. The motives of Swedish and German investors differ. Thus, for Swedish investors R&amp;D, economical free-dom and trade balance are the influencing factors, but for Germany only trade balance and wage level are important. The conclusion is that different determinants triggers foreign di-rect investment in transitional economies in different ways.
328

Ridged sea ice modelling in climate applications

Mårtensson, Sebastian January 2013 (has links)
This work aims to increase our understanding of the nature of large scale features of sea ice from a dynamics point of view.Sea ice plays an important part in the exchange of heat and humidity between sea and air and thus is an important component of the climate system. Its physical presence also directly impacts the various forms of life such as diatoms, polar bears and humans alike.The dynamics of sea ice affect both weather and climate, through the large scale drift in the Arctic from the Siberian coast towards Fram Strait, through creation of cracks in the ice called leads or polynyas, and through ridging and other mechanical deformations of ice floes.In this work, we have focused on modelling of ridged ice for a number of reasons. Direct observations of the internal ice state is very difficult to perform and in general, observations of sea ice are either sparse or of limited information density. Ridged ice can be seen as the memory of high ice stress events, giving us a view on these highly dynamic events. Ridging is of major importance for the ice thickness distribution, as the thickest ice can only be formed through mechanical processes. Further, ridged ice is of direct interest for anyone conducting shipping through seasonal or perennial ice covered seas as it can form impenetrable barriers or in extreme even cases crush a ship caught within the ice pack. To this end, a multi-category sea ice model, the HELsinki Multi category Ice model (HELMI), was implemented into the Rossby Centre Ocean model (RCO). HELMI has explicit formulations for ridged and rafted ice, as well as sub-grid scale ice thickness distribution (a feature shared with other multi category models) and an ice strength based on energetics. These features give RCO better representation of sub-grid scale physics and gives us the possibility to study the deformed ice in detail. In paper I we look at the change in behaviour in the Arctic as the ice becomes more mobile, leading to a slight increase in modelled ridged ice volume in the central Arctic, despite a general trend of a decreasing ice cover.Paper II takes us to the Baltic Sea and the possibilities of modelling ridge ice concentration with a statistical model.In Paper III we investigate how the diminishing ice cover in future scenarios affects the biological activity in the Baltic Sea.Finally Paper IV investigates how the ice stress and the internal ice force can be interpreted in terms of ice compression on the ship scale. / <p>At the time of the doctoral defence the following paper was unpublished and had a status as follows: Paper 4: Manuscript</p>
329

Grave fra Østersøområdet i Boreal og tidlig Atlantisk tid : et multiregionalt studie / Early Mesolithic burials from the area around the Baltic Sea : a multiregional study

Frydendal Nielsen, Katrine January 2012 (has links)
The aim of this paper is to examine if any homogeneity or heterogeneity can be traced in burials from Preboreal, Boreal and Early Atlantic period, in the area of the Baltic Sea. Furthermore, the paper will deal with the Early Mesolithic burials based on theoretical perspectives on rituals, materiality and agency.To enable the purpose of identifying the homogeneity or heterogeneity of the data, relational multi-varied Correspondence Analysis of the individuals and their artifact variations, body position, burial type etc. have been applied.The data used in this study contain information from 41 sites including 171 graves with 194 individuals from nine different countries (Denmark, Finland, Germany, Latvia, Lithuania, Norway Poland, Russia and Sweden). The study is based on the work Mesolithische Bestattungen in Europa. Ein Beitrag zur vergleichenden Gräberkunde. Teil I-II of Judith M. Grünberg from 2000, however some new sites and graves have been added.This study is expected to contribute new contextual interpretations of the Early Mesolithic burials of the area of the Baltic Sea.
330

Changes in condition of herring (Clupea harengus) in Swedish coastal waters

Persson, Martin January 2010 (has links)
The condition of the herring (Clupea harengus) in the Baltic Sea has decreased during the past 30-40 years. This decrease could be explained by different factors; (1) change in diet due to changes in zooplankton community, (2) changes in water temperature and salinity, (3) increasing nutrient inputs and (4) competition for food with other species such as sprat (Sprattus sprattus). In this study the change in condition was analysed using the Fulton’s condition index, and by looking at age and sex of the fish as well as the season and locationthe fish was caught, the differences between these factors were presented. Data from the national Swedish contaminant monitoring programme where used from four locations in the Baltic Sea and two locations at the Swedish West coast. The data was analysed using multiple regressions in R Commander. The result show that the condition, and the temporal trends in condition value, varies at different locations, with higher condition values and increasing temporal trends at the Swedish West coast, compared to the Baltic Sea with lower condition values and where three of four locations show decreasing temporal trends. The condition varied between spring and autumn caught herring as well, while age and sex showed less significant differences.

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