During the last deglaciation, Greenland ice core records exhibit multiple, high frequency climate events including the Oldest Dryas, Bølling-Allerød and Younger Dryas, which may be linked to meltwater routing of the Laurentide Ice Sheet (LIS). Previous studies show episodic meltwater input, via the Mississippi River to the Gulf of Mexico (GOM) several thousand years before the onset of the Younger Dryas until ~13.0 kcal (thousand calendar) yrs, when meltwater may have switched to an eastern spillway, reducing thermohaline circulation (THC). Data from laminated Orca Basin in the GOM, constrained by 34 Accelerator Mass Spectrometry (AMS) 14C dates, provide the necessary resolution to assess GOM sea-surface temperature (SST) history and test the meltwater routing hypothesis. Paired Mg/Ca and δ18O data on the Foraminifera species Globigerinoides ruber (pink and white varieties) document the timing of meltwater input and temperature change with decadal resolution. White G. ruber SST results show an early 5°C increase at 17.6-16.0 kcal yrs and several SST decreases, including at 16.0-14.7 kcal yrs during the Oldest Dryas (2°C) and at 12.9-11.7 kcal yrs during the Younger Dryas (2.5°C). While the early deglaciation shows strong similarities to records from Antarctica and Tobago Basin, the late deglaciation displays climate events that coincide with Greenland and Cariaco Basin records, suggesting that GOM SST is linked to both northern and southern hemisphere climate. Isolation of the ice-volume corrected δ18O composition of seawater (δ18OGOM) shows multiple episodes of meltwater at ~16.4-15.7 kcal yrs and ~15.2-13.1 kcal yrs with white G. ruber δ18OGOM values as low as -2.5%0. The raw radiocarbon age of the cessation of meltwater in the GOM (11.375±0.40 14C kcal yrs) is synchronous with large changes in tropical surface water Δ14C, a proxy for THC strength. An early meltwater episode beginning at 16.4 kcal yrs during the Oldest Dryas supports the suggestion of enhanced seasonality in the northern North Atlantic during Greenland stadials. We suggest a corollary to the seasonality hypothesis that in addition to extreme winters during stadials, warm summers allowed for LIS melting, which may have enhanced THC slowdown.

In many areas of India and Australia, groundwater has been and is being withdrawn at rates far beyond the recharge capacity of the aquifer. The resulting depletion of groundwater supplies has a number of adverse social, economic and environmental consequences. These consequences and conflicts have led to a debate over the suitable institutional arrangements to manage common pool groundwater resources in a sustainable manner.

<p>The case study was made in the area of Kiru Valley, Tanzania, in order to study the conflicts over the water in the river Dodumera, and also to understand how the villages Mawemairo, Matufa and Mapea have been affected by the construction of the IFAD irrigation scheme. The aim was to connect the conflicts in the area with a general view of how water can create such conflicts. The method used in the case study was semi-structured interviews. The results from the interviews made with farmers and officials in Kiru Valley was analysed through general theories about water conflicts and theories about governing common-pool resources, such as Ostrom’s eight principles and the theory the Tragedy of the Commons. The analysis was also made through the IFAD poverty reduction strategy programme (PRSP). The conclusion made on the basis of this analysis was that the IFAD project, in Kiru Valley, was in correlation with the PRSP and an attempt to reduce poverty in the two villages Mawemairo and Matufa. The project has been very successful and has contributed to an increase of livelihood and development in the villages. However, the scheme has also affected other villages, such as Mapea. The scheme has contributed to a decrease of water availability in the Dodumera River for Mapea. Nowadays they only rely on rain-fed irrigation. The conflicts have been affected by the scheme, not so much in the quantity of the conflicts but more in the target of the conflicts. Before the construction of the scheme the conflicts was directed at the big-scale farmers, now they are directed at the scheme. On the other hand, the scheme has helped reducing the conflicts between the farmers in Mawemairo and Matufa. There are solutions to conflicts and water scarcity, such as more efficient irrigation techniques and Ostrom’s principles on governing the common-pool resources.</p>

No description available.

<p>I have done a follow up study of the restoration of two rivers, Röälven and Grundan, in order to evaluate the effects of the restoration on the endemic population of trout. Both rivers have been used for timber floating during many years throughout the 20^th century, and because of this, had all obstacles such as rocks and wood parts removed. In 2004-2005 both rivers were restored, and rocks and wood were put back into the rivers. Spawning grounds were created and boulder dams were constructed to promote the streaming water. The result showed that the trout population of both rivers increased after the restoration, but also that the trout population of Röälven increased more than that of Grundan. My conclusion is that the way the restoration is of a river contributes to the result.</p>

<p>I denna uppsats undersöks om terminspriset på el är snedvridet jämfört med det framtida spotpriset. Undersökningen har fokuserats på elmarknaden och den prissättning som sker på den Nordiska elbörsen, Nord Pool. Först presenteras en teori om varför det finns en derivatamarknad och vilken betydelse den har. Vidare så förklaras vad som menas med spot- respektive terminspris och därefter förklaras hur de förhåller sig till varandra utifrån ekonomisk teori. Sedan introduceras hur marknaden fungerar på Nord Pool och hur prissättningen sker av spot- och terminspriset. Detta följs upp med hur det går till rent praktiskt att handla med ett terminskontrakt i form av ett futureskontrakt. Olika ekonometriska tester kommer sedan att utföras för att se på variablernas underliggande trender och slutligen undersöks huruvida futurespriset är en snedvriden skattning av framtida spotpris. Datamaterialet som har använts är veckovisa observationer från vecka 1, 1996 till vecka 41, 2007. Resultatet visar på att futurespriset är en snedvriden skattning av framtida spotpris då futurespriset i genomsnitt visade sig vara högre än framtida spotpris.</p>

Phenotypic plasticity is the ability of a genotype to express different phenotypes in different environments. Despite its common occurrence, few have investigated differences in plasticity between populations, the selection pressures responsible for it, and costs and constraints associated with it. In this thesis, I investigated this by studying local adaptation and phenotypic plasticity in populations of the common frog Rana temporaria, inhibiting islands with different pool types (temporary, permanent or both). The tadpoles develop in these pools, and have to finish metamorphosis before the pool dries out. I found that the tadpoles were locally adapted both in development time and in phenotypic plasticity of development time. Tadpoles from islands with temporary pools had a genetically shorter development time than tadpoles from islands with permanent pools. The population differentiation in development time, estimated as QST, was larger than the population differentiation in neutral molecular markers (FST), which suggest that divergent selection among the populations is responsible for the differentiation. Moreover, tadpoles from islands with more variation in pool drying regimes had higher phenotypic plasticity in development time than tadpoles from islands with only one pool type present. Interestingly, increased migration among populations did not select for increased plasticity, rather it was the local environmental variation that was important. This adaptation has occurred over a short time scale, as the islands are less than 300 generations old. In temporary pools, it is adaptive to finish development before the pool dries out. This could be achieved by entering the metamorphosis at a smaller size, as a smaller size takes shorter time to reach. However, I found that there is a minimum threshold size below which tadpoles’ cannot enter metamorphosis, and that there had been no evolution of this threshold size in populations living in temporary environments. That suggests that this developmental threshold is tightly linked to physiological constraints in the developmental process. Despite their expected importance as constrains on the evolution of plasticity, costs of plasticity are often not found in nature.  However, theories of why they are absent have not been tested empirically. In this thesis, I show that fitness costs of phenotypic plasticity are only found in populations with genotypes expressing high levels of phenotypic plasticity, while in populations with low-plastic genotypes, I find costs of not being plastic. This suggests that costs of plasticity increase with increased level of plasticity in the population, and that might be a reason why costs of plasticity are hard to detect.

No description available.

I denna uppsats undersöks om terminspriset på el är snedvridet jämfört med det framtida spotpriset. Undersökningen har fokuserats på elmarknaden och den prissättning som sker på den Nordiska elbörsen, Nord Pool. Först presenteras en teori om varför det finns en derivatamarknad och vilken betydelse den har. Vidare så förklaras vad som menas med spot- respektive terminspris och därefter förklaras hur de förhåller sig till varandra utifrån ekonomisk teori. Sedan introduceras hur marknaden fungerar på Nord Pool och hur prissättningen sker av spot- och terminspriset. Detta följs upp med hur det går till rent praktiskt att handla med ett terminskontrakt i form av ett futureskontrakt. Olika ekonometriska tester kommer sedan att utföras för att se på variablernas underliggande trender och slutligen undersöks huruvida futurespriset är en snedvriden skattning av framtida spotpris. Datamaterialet som har använts är veckovisa observationer från vecka 1, 1996 till vecka 41, 2007. Resultatet visar på att futurespriset är en snedvriden skattning av framtida spotpris då futurespriset i genomsnitt visade sig vara högre än framtida spotpris.

<p>Theories of ambition have taught us that higher offices are valuable commodities to certain politicians, and under the right circumstances, the benefits of running for an office outweigh the associated risks. Yet some ambitious politicians emerge as candidates while others do not. In this dissertation, I present a Theory of Strategic Candidacy Decisions to explain how primary elections unfold. With new comprehensive data on the timing of candidacy decisions, I test several hypotheses regarding the determinants of electoral and fundraising success, the timing of strategic candidacy decisions, the interactions of prospective officeholders, and the impact of strategic retirements on primary races for the United States Senate. Using both qualitative and quantitative tools, including event history techniques to capture the complex dynamics of primaries, I find that potential candidates interact with one another and the unique political context within each race and emerge from the pool of potential candidates in systematic ways. In the end, the strategic behavior of ambitious politicians has implications for the slate of candidates available to the electorate and ultimately, on the quality of representation between legislators and constituents.</p> / Dissertation