A parameter free approach for the calculation of the crystal field splitting of the lowest Russel-Saunders J-multiplet in f-electron systems has been developed and applied to selected compounds. The developed theory is applicable to general symmetries and is based on symmetry constrained density functional theory calculations in the local density or in the generalised gradient approximation. The magnetocrystalline anisotropy of Gd has been analysed. It has been shown that the peculiar orientation of the easy axis of magnetisation is consistent with an S-ground state. Further, the temperature dependence of the easy axis of magnetisation has been investigated and it has been shown that the temperature driven reduction of the effective magnetisation is the principal mechanism responsible for it. A new method has been developed that allows for theoretical studies of the electronic structure and total energy of elements and compounds in an intermediate valence regime. The method combines model and first-principles band structure calculations, therefore being accurate and computationally efficient. It has been applied to Yb metal under pressure obtaining a remarkable agreement with experimental observations for the equation of state and the x-ray absorption spectroscopy.

This thesis is divided into two parts. In the first part we focus mainly on certain aspects of the AdS/CFT correspondence. The AdS/CFT correspondence is a proposed duality between Type IIB superstring theory on AdS5 x S5 and N = 4 supersymmetric Yang-Mills theory. In the BMN limit string states located in the center of AdS5 rotate quickly around the equator of the S5 and correspond, in the dual theory, to operators constructed as long chains of sub-operators. This structure of the operators can be formulated as a spin chain and by using the Bethe ansatz their properties can be obtained by solving a set of Bethe equations. Having infinitely many sub-operators, there are methods for solving the Bethe equations in certain sectors. In paper III finite size corrections to the anomalous dimensions in the SU(2) sector are calculated to leading order. Inspired by the chain structure of the corresponding operators, the theory of string bits treats the strings as a discrete sets of points. This theory suffers from the problem of fermion doubling, a general pathology of fermions on a lattice. In paper II we show how to adjust the theory in order to avoid this problem and, in fact, use the fermion doubling to our advantage. The second part of the thesis studies the low energy behaviour of SU(2) Yang-Mills theory in 4 space-time dimensions. In paper I we perform numerical calculations on an effective action for this theory. We propose the existence of a knotted trajectory within the dynamics of this effective action.

Individual proteins, and small collections of proteins, have been extensively studied for at least two hundred years. Today, more than 350 genomes have been completely sequenced and the proteomes of these genomes have been at least partially mapped. The inventory of protein coding genes is the first step toward understanding the cellular machinery. Recent studies have generated a comprehensive data set for the physical interactions between the proteins of Saccharomyces cerevisiae, in addition to some less extensive proteome interaction maps of higher eukaryotes. Hence, it is now becoming feasible to investigate important questions regarding the evolution of protein-protein networks. For instance, what is the evolutionary relationship between proteins that interact, directly or indirectly? Do interacting proteins co-evolve? Are they often derived from each other? In order to perform such proteome-wide investigations, a top-down view is necessary. This is provided by network (or graph) theory. The proteins of the cell may be viewed as a community of individual molecules which together form a society of proteins (nodes), a network, where the proteins have various kinds of relationships (edges) to each other. There are several different types of protein networks, for instance the two networks studied here, namely metabolic networks and protein-protein interaction networks. The metabolic network is a representation of metabolism, which is defined as the sum of the reactions that take place inside the cell. These reactions often occur through the catalytic activity of enzymes, representing the nodes, connected to each other through substrate/product edges. The indirect interactions of metabolic enzymes are clearly different in nature from the direct physical interactions, which are fundamental to most biological processes, which constitute the edges in protein-protein interaction networks. This thesis describes three investigations into the evolution of metabolic and protein-protein interaction networks. We present a comparative study of the importance of retrograde evolution, the scenario that pathways assemble backward compared to the direction of the pathway, and patchwork evolution, where enzymes evolve from a broad to narrow substrate specificity. Shifting focus toward network topology, a suggested mechanism for the evolution of biological networks, preferential attachment, is investigated in the context of metabolism. Early in the investigation of biological networks it seemed clear that the networks often display a particular, 'scale-free', topology. This topology is characterized by many nodes with few interaction partners and a few nodes (hubs) with a large number of interaction partners. While the second paper describes the evidence for preferential attachment in metabolic networks, the final paper describes the characteristics of the hubs in the physical interaction network of S. cerevisiae.

The study aims to explain the role of external causes in René Descartes’s (1594–1650) and Benedictus de Spinoza’s (1632–1677) accounts of the mastery of the passions. It consists in three parts: the mind-body union, the passions and their classification, and the mastery of the passions. In the first part I argue that Descartes’s conception of the mind-body union consists in two elements: mind-body interaction and the experience of being one with the body. Spinoza rejects the first element because there cannot be psychophysical laws. He accepts the second element, but goes beyond Descartes, arguing that the mind and body are identical. In the second part I discuss the classifications of the passions in the Passions of the Soul and the Ethics and compare them with the one Spinoza presents in the Short Treatise. I explain that hilaritas is an affect that expresses bodily equilibrium and makes it possible for the mind to be able think in a great many ways. Furthermore, I consider the principles of imagination that along with imitation and the striving to persevere provide a causal explanation for the necessary occurrence of the passions. In the last part I argue that in Descartes the external conditions do not have a significant role in the mastery of the passions. For Spinoza, however, they are necessary. Commentators like Jonathan Bennett fail to see this. Hilaritas requires a diversity of sensual pleasures to occur. As Medea’s case shows, reason is not detached from Nature. Spinoza attempts to form a stronger human nature and to enable as many people as possible to think adequately. His recognition of the need for appropriate external conditions and a society in which ideas can be expressed freely allows him to present an ethics with a practical application, instead of another utopia or fiction.

No description available.

I skolans styrdokument finns uttryckt att undervisningen ska utgå från den enskilda eleven. Många elever upplever idag att så inte är fallet. De senaste åren har elever som är obehöriga att söka till ett nationellt program på gymnasiet ökat i antal. 1998, då de nya behörighetskraven infördes, var siffran 8.6 % i hela landet, 2006 var den 10.5 %. Studiens syfte är att undersöka möjliga faktorer som påverkat ungdomars högstadietid så negativt att de inte har klarat skolans krav. Fokus har lagts på personligt och allmändidaktiskt bemötande. Genom att anta elevperspektivet tar undersökningen till vara elevernas egna upplevelser av högstadietiden. Tidigare forskning inom området påvisar att elevperspektivet blir allt vanligare. I två avhandlingar, som redogörs för i examensarbetet, framförs elevperspektivet och där talas speciellt om två faktorer som är viktiga för eleverna. Det är lärarens elevsyn och huruvida eleverna känner meningsfullhet i skolarbetet. Avhandlingarna visar även att undervisningen bör utgå från elevens vardag och kultur om den ska bli meningsfull och motivera eleverna till fortsatt lärande. Undersökningen tar avstamp i tidigare forskning men försöker belysa ett kunskapsglapp genom att sammanföra två viktiga faktorer i samma studie, personligt och allmändidaktiskt bemötande. Vidare ges ett antal förslag till fortsatt forskning av faktorer och samband som hade fyllt en funktion för det här examensarbetets fortskridande. Undersökningen utfördes på det individuella programmet i en kommun i Mellansverige. Två metoder användes, dels en enkätundersökning i vilken 48 elever deltog och dels intervjuer med 8 elever. Enkätfrågorna är utformade med fokus på personligt och allmändidaktiskt bemötande men även på faktorer som eleverna själva upplever kan ha påverkat deras högstadietid. Intervjuerna har utförts för att fördjupa enkätfrågorna och för att upptäcka eventuella perspektiv som har förbisetts. Enkäternas svarsfrekvens är 98 %. Resultatet visar att en majoritet av eleverna saknar att bli sedda som egna individer och att både det personliga och det allmändidaktiska bemötandet är av stor betydelse för eleverna. Resultatet visar även på vikten av att eleverna behöver känna sig lyssnade på och respekterade. En slutsats i undersökningen är att eleverna upplever sig ha mycket kunskap om sina egna behov. Det är en tydlig motivationsfaktor för eleverna att aktivt få delta i sin utbildning och skolgång.

Föreliggande uppsats har kritiskt granskat, analyserat och diskuterat Läroplanens teoretiska kunskapssyn. Om analysen håller så anser jag mig ha visat vilka resonemang, utifrån den kognitiva relativismen, som Lpf 94 bygger på. Hur den kognitiva relativismen kommer fram till att kunskap är relativ kan se lite olika ut. Minst tre underliggande teser kan urskiljas vilka alla kan ligga till grund för Lpf 94s kunskapssyn. Dessa är kunskapssociologisk relativism, epistemisk relativism och ontologisk relativism. Alla förnekar de, var för sig, minst ett av tre de nödvändiga villkoren i den traditionella analysen av kunskap, vilken innebär att kunskap är sann berättigad tro. Jag har även presenterat, analyserat samt diskuterat de elementära och logiska motsägelser som följer en relativistisk kunskapssyn. Dessa är av den omfattningen att det kan finnas tillräckliga skäl att förkasta en relativistisk kunskapssyn oavsett vilket relativistiskt resonemang som ligger till grund för Lpf 94s relativa kunskapssyn. Min slutsats är att synen på att teoretisk kunskap är relativ inte håller och bör förkastas, vilket innebär att läroplanen i framtiden bör bygga på en objektiv kunskapssyn.

Modern computing platforms strive to support mobile code without putting system security at stake. These platforms can be viewed as open systems, as the mobile code adds new components to the running system. Establishing that such platforms function correctly can  be divided into two steps. First, it is shown that the system functions correctly regardless of the mobile components that join it, provided that they satisfy certain assumptions. These assumptions can, for instance, restrict the behavior of the component to ensure that the security policy of the platform is not violated. Second, the mobile component is checked to satisfy its assumptions, before it is allowed to join the system. This thesis presents algorithmic verification techniques to support this methodology. In the first two parts, we present techniques for the verification of open systems relative to the given component assumptions. In the third part, a technique for the  quick certification of mobile code is presented for the case where a particular type of program rewriting is used as a means of enforcing the component assumptions.In the first part of this study, we present a framework for the verification of open systems based on explicit state space representation. We propose Extended Modal Transition Systems (EMTS) as a suitable structure for representing the state space of open systems when assumptions on components are written in the modal μ-calculus. EMTSs are based on the Modal Transition Systems (MTS) of Larsen and provide a formalism for graphical specification and facilitate a thorough understanding of the system by visualization. In interactive verification, this state space representation enables proof reuse and aids the user guiding the verification process. We present a construction of state space representations from process algebraic open system descriptions based on a maximal model construction for the modal μ-calculus. The construction is sound and complete for systems with a single unknown component and sound for those without dynamic process reation. We also suggest a tableau-based proof system for establishing temporal properties of open systems represented as EMTS. The proof system is sound in general and complete for prime formulae.The problem of open system correctness  also arises in compositional verification, where the problem of showing a global property of a system is reduced to showing local properties of components. In the second part, we extend an existing  compositional verification framework for Java bytecode programs. The framework employs control flow graphs with procedures to model component implementations and open systems for the purpose of checking control-flow properties. We generalize these models to capture exceptional and multi-threaded behavior. The resulting control flow graphs are specifically tailored to support the compositional verification principle; however, they are sufficiently intuitive and standard to be useful on their own. We describe how the models can be extracted from program code and give preliminary experimental results for our implementation of the extraction of control flow graphs with exceptions. We also discuss further tool support and practical applications of the method.In the third part of the thesis, we develop a technique for the certification of safe mobile code, by adapting the proof-carrying code scheme of Necula to the case of security policies expressed as security automata. In particular, we describe how proofs of policy compliance can  be automatically generated for  programs that include a monitor for the desired policy. A monitor is an entity that observes the execution of a program and terminates the program if a violation to the property is about to occur. One way to implement such a monitor is by rewriting the program to make it self-monitoring. Given a property, we characterize self-monitoring of Java bytecode programs for this property by an annotation scheme with annotations in the style of Floyd-Hoare logics. The annotations generated by this scheme can be extended in a straightforward way to form a correctness proof in the sense of axiomatic semantics of programs. The proof generated in this manner essentially establishes that the program satisfies the property because it contains a monitor for it. The annotations that comprise the proofs are simple and efficiently checkable, thus facilitate certification of mobile code on devices with restricted computing power such as mobile phones. / QC 20100628

In the present thesis, the reaction mechanisms of several di-zinc hydrolases have been explored using quantum chemical modeling of the enzyme active sites. The studied enzymes are phosphotriesterase (PTE), aminopeptidase from Aeromonas proteolytica (AAP), glyoxalase II (GlxII), and alkaline phosphatase (AP). All of them contain a binuclear divalent zinc core in the active site. The density functional theory (DFT) method B3LYP functional was employed in the investigations. The potential energy surfaces (PESs) for various reaction pathways have been mapped and the involved transition states and intermediates have been characterized. The hydrolyses of different types of substrates were examined, including phosphate esters (PTE and AP) and the substrates containing carbonyl group (AAP and GlxII). The roles of zinc ions and individual active-site residues were analyzed and general features of di-zinc enzymes have been characterized. The bridging hydroxide stabilized by two zinc ions has been confirmed to be capable of the nucleophile in the hydrolysis reactions. PTE, AAP, and GlxII all employ the bridging hydroxide as the direct nucleophile. Furthermore, it is shown that either one of or both zinc ions provide the main catalytic power by stabilizing the negative charge developing during the reaction and thereby lowering the barriers. In the cases of GlxII and AP, one of zinc ions also contributes to the catalysis by stabilizing the leaving group. These features perfectly satisfy the two requisites for the hydrolysis, i.e. sufficient nucleophilicity and stabilization of charge. A competing mechanism, in which the bridging hydroxide acts as a base, was shown to have significantly higher barrier in the case of PTE. For phosphate hydrolysis reactions, it is important to characterize the nature of the transition states involved in the reactions. Associative mechanisms were observed for both PTE and AP. The former uses a step-wise associative pathway via a penta-coordinated intermediate, while the latter proceeds through a concerted associative path via penta-coordinated transition states. Finally, with PTE as a test case, systematic evaluation of the computational performance of the quantum chemical modeling approach has been performed. This assessment, coupled with other results of this thesis, provide an effective demonstration of the usefulness and powerfulness of quantum chemical active-site modeling in the exploration of enzyme reaction mechanisms and in the characterization of the transition states involved. / QC 20100715 / Quantum Chemical Modeling of Binuclear Zinc Enzymes

The aim of this thesis was to investigate carbon based molecular materials at first principles levels. Special attention has been paid to simulations of X-ray spectroscopies, including near edge X-ray absorption fine structure (NEXAFS), X-ray photoelectron, and X-ray emission spectroscopy, which can provide detailed information about core, occupied and unoccupied molecular orbitals of the systems under investigation. Theoretical calculations have helped to assign fine spectral structures in high resolution NEXAFS spectra of five azabenzenes (pyridine, pyrazine, pyrimidine, pyridazine and s-triazine), and to identify different local chemical environments among them. With the help of NEXAFS, the characters of important chemical bonds that might be responsible for the unique magnetic properties of the tetracyanoethylene compound has been revealed. Calculations have demonstrated that X-ray spectroscopies are powerful tools for isomer identification and structure determination of fullerenes and endohedral metallofullerenes. A joint experimental and theoretical study on metallofullerene Gd@C82 has firmly determined its equilibrium structure, in which the gadolinium atom lies above the hexagon on the C2 axis. It is found that the gadolinium atom could oscillate around its equilibrium position and that its oscillation amplitude increases with increasing temperature. In this thesis, several new computational schemes for large-scale systems have been proposed. Parallel implementation of a central insertion scheme (CIS) has been realized, which allows to effectively calculate electronic structures of very large systems, up to 150,000 electrons, at hybrid density functional theory levels. In comparison with traditional computational methods, CIS provides results with the same high accuracy but requires only a fraction of computational time. One of its applications is to calculate electronic structures of nanodiamond clusters varying from 0.76 nm (29 carbons) to 7.3 nm (20,959 carbons) in diameter, which enabled to resolve the long-standing debate about the validity of the quantum confinement model for nanodiamonds. Electronic structures and X-ray spectroscopies of a series of single-walled carbon nanotubes (SWCNTs) with different diameters and lengths have been calculated, which have made it possible to interpret the existing experimental results. / QC 20100727