Genetically encoded, site-specific incorporation of unnatural amino acids (UAA)into proteins through selective recoding of an amber stop codon provides apowerful route for expressing synthetic proteins in living cells. Recoding of theamber stop codon is achieved by introducing an amber suppressortRNA/synthetase pair orthogonal to the endogenous tRNA complement intocells. Methanosarcina is a methane producing archaea with the unusualcapability of suppressing the stop codon (specifically the amber codon). Bysuppressing the amber codon Methanosarcina facilitate the incorporation of thenon-canonical amino acid pyrrolysine (pyl). The suppressing mechanismoriginates from a evolutionary unique Pyrrolysyl-tRNA synthetase (PylRS) and itsmatching tRNApyl. The PylRS has been further evolved and modified to allowincorporation of a wide range of UAAs. Amber suppression is today used tocontrol and study protein function in living cells. By making a series of wellcontrolledexperiments with HEK293T cells we aimed to develop this techniqueinto a robust and general tool for mammalian cell biology. Specifically we weretesting the incorporation of the unnatural amino acid bicyclononyne (BCN) by aset of known PylRS mutants. Our results suggest the mutant aaRS PylRS “AF” isthe most robust and efficient synthetase for BCN. We have improved ambersuppression by determining which factors leads to a more efficient method andsimultaneously decreasing the cost of the method.

This thesis reviews the theory of group extensions, gerbes and twisted K-theory. Application to anomalies in gauge theory is briefly discussed. The main results are presented in two appended scientific papers. In the first paper we establish, by construction, a criterion for when an infinite dimensional abelian Lie algebra extension corresponds to a Lie group extension. In the second paper we introduce the fractional loop group L_qG, construct highest weight modules for the Lie algebra and discuss an application to twisted K-theory on G. / QC 20101111

The Yang-Mills gauge theories play prominent role in modern high energy physics and the direct non-perturbative calculations present the main challenge in the field.Two dimensional gauge theories provide a nice playground where it is possible to carry out exact computations and at the same time some non-trivial phenomena canbe studied. This thesis is devoted to review and summarize a core portion of the quantum version of this field, accompanying the reader through the technicalities that one can encounter during the first approach to the subject.The thesis starts with a brief introduction to the subject and a brief review of the literature, the first two chapters are then spent on the computation of the partition functions over the simplest surfaces, i.e. disk and cylinder, using different formalisms.In chapter 4 there is presented the generalization of the procedure in order to find the general partition function that can be applied over any orientable surface (not necessarily closed). Interesting observables in this theory are the so called Wilson loops, chapter 5 contains the definition and a presentation of the non-intersecting ones over closed surfaces. In the end some of these encountered formulae have been applied to U(1) and SU(N) groups, i.e. we derived some partition functions of Maxwell theory and quantum chromodynamics over non-trivial surfaces and we gave the tools to explore more complex cases. The appendices contain one a brief review of the mathematics, the other all the step by step computations performed during the proofs.

No description available.

Boreal forest is the largest biome in the world and therefore holds much of the global carbon and has a great root system size which makes it relevant to analyze how common grazing animals affect this environment. Roots have many different roles in the ground and for the plants, where fine roots take up nutrients and circulate biomaterials among other things and coarser roots make up most of the biomass and sequestrate most carbon. Herbivores have been shown to affect plant productivity and remove aboveground biomass through their grazing, and this could have both positive, negative, and neutral effects. The purpose of this study was to examine how the root biomass varies depending on reindeer grazing in boreal forests, and this was done by studying how tree distance, ground depth and grazing reindeer affect root biomass. Fine, coarse, and very coarse roots were sampled in ungrazed and grazed areas in northern Finland. This was done with a distance of 1-3 meters from trees and depths in increments of 0-25 cm. No factors were significant for coarse roots and treatment not affecting them could be explained by some plants being able to survive defoliation or simply not being reduced by reindeer. Distance hardly affected root biomass which other studies also found, and also similar to other studies depth affected fine roots. Grazing was shown to reduce fine and very coarse root biomass. Loss of fine roots can affect microbial activity in the soil and loss of coarser roots can possibly affect the area long-term in different ways.

In this project, we compute the Hagedorn temperature in N=4 supersymmetric Yang-Mills theory and in pure Yang-Mills theory by determining the temperature at which the partition function becomes non-analytic. The gauge group is taken to be either SU(N) or O(N) in the large N limit. We derive the partition function with combinatorics, counting the single-trace operators (and thereby the gauge invariant states) allowed by the theory. Then we determine the single-particle partition functions associated with fermions, bosons, and gluons, whose contributions make up the full partition function. These single-particle functions are derived independently using two different approaches (both producing the same result), where the first method relies on the state-operator correspondence of conformal field theories, and the second relies on the spin representations of the particles. We also derive the partition function on a compact space by integrating over the gauge group manifold. By using random matrix theory and standard large N methods, the integral simplifies. The resulting Hagedorn temperature matches that derived from combinatorics. We compute the precise temperature in two theories.

No description available.

This thesis defends a novel interpretation of the normative foundations of Hegel's mature social and political philosophy. It argues that autonomous agency is grounded in a drive to comprehend ourselves, which gives us an aim to which we are inescapably committed as agents. It argues that this aim ultimately makes it rational to cultivate and act out of a feeling of “ethical love”, which is a positive evaluative attitude towards the goods of other individuals that, in turn, implies a commitment to the social and political institutions Hegel outlines in his theory of Sittlichkeit, or ethical life. Ethical love is the ultimate way in which individuals make themselves comprehensible to themselves; ethical life is the way in which they express that love. It is for this reason that acting autonomously ultimately requires participating in such institutions. I suggest that this interpretation avoids some of the shortcomings of alternative approaches to this matter. Chapter 1 introduces the notion of autonomous agency as underpinned by a drive towards self-comprehension. In chapter 2, I argue that this drive operates both with respect to our individual identities (our “characters”) and developmentally, over time, in that agents characterised by this drive are led ultimately to conceive of themselves as “persons”, in Hegel's technical sense: as agents who are rationally compelled to recognise others. In chapters 3 and 4, I show that there is a tension between these two aspects of our identities, and that Hegel's theory of objective mind is effectively the working out of this tension.

Central to Realism's framing of the international are its conception of the inside/outside structure of political form and the idea of a state of nature. This thesis provides a materialist critique of these conceptions. Its starting point is that the Marxist criticism of Realism has fallen short because Marxism in IR has constructed no theory of the political and as a result it has been unable to answer Realism's perception of the ‘tragic' and unchanging nature of international political existence. To remedy this deficiency, the thesis both establishes an alternative understanding of Marx for IR and draws upon Adorno's extension and deepening of Marxian critical theory. The argument next elaborates a reading of Marx's theory of capital that reveals a considerable degree of hitherto unappreciated thematic congruence with Realism's understanding of the international as a timeless scene of entrapment. It then mobilises Adorno's philosophical anthropology to explain this similarity, focusing on the critical accounts of abstraction in both Marx and Adorno. Finally, it uses these theoretical elements to address the question of political form directly, taking up specific aspects of Carl Schmitt's, Giorgio Agamben's and Walter Benjamin's thinking concerning sovereignty and the exception and reading them through the frame of Adorno's critique of the concept. The result is a critical theory of political form that: (i) can explain, without conceding to, the Realist conceptions both of the necessary inside/outside structure of the political and of the international as a timeless state of nature; and (ii) can demonstrate an instrinsic theoretical connection between the global nature of capital and the bounded and delimited form of the political in a way that has not been achieved before in IR.

Syftet med detta arbete är att försöka komma fram till hur elever som läser tekniskt och naturvetenskapligt program på gymnasiet uppfattar ämnet fysik. En enkät ligger till grund för undersökningen. Enligt eleverna blir ämnet tråkigt när det är för mycket teori och muntlig undervisning. Däremot blir ämnet intressantare när eleverna får ägna sig åt laborationer och experiment. En viktig faktor för både undervisningen och trivseln i klassrummet är läraren. Resultatet av undervisningen påverkas också positivt om eleverna har roligt när de undervisas. Överlag är fysikämnet intressant enligt eleverna och det finns ett tydligt intresse för att få förståelse för olika fenomen samtidigt som flertalet elever ser valet av gymnasieprogram som en framtidsinvestering.