Many T=3 plant and insect viruses use a molecular switch in form of order/disorder of a segment of the polypeptide chain to regulate the quasi-equivalent contacts. The structure of a mutant of the T=3 capsid of bacteriophage fr confirms that this virus and other members of the Leviviridae family lack a switch mechanism. The geometric principles underlying the construction of spherical virus capsid do not allow more than 60 protein monomers to from a capsid while maintaining an identical chemical environment. Most virus capsid, however, contain many more protein subunits. Quasi-equivalence explains how the capsid proteins can have slightly different interactions in the virus shell. Quasi-equivalence requires the capsids to be constructed from multiples of 60 subunits, where the T number denotes the multiplicity. The structure of the T=4 Nudaurelia capensis ω Virus shows a molecular switch in form of a C-terminal helix inserted in some contacts between protein dimers. This virus is very similar in structure to the T=3 nodaviruses. In the nodaviruses a five-membered helix bundle, formed by cleaved peptides around the five-fold axes on the inside of the shell, are suggested to aid in membrane translocation of the genomic RNA. In Nudaurelia capensis ω Virus the helix bundle is formed by 10 helices, of which 5 are still covalently attached to the capsid proteins. Bacteriophage HK97 has T=7 quasi-symmetry. A domain that is degraded during maturation and is not present in the structure of the mature virion controls the quasi-equivalence. During maturation covalent bonds are formed between the protein subunits, producing a set of interlocking covalently bound rings, resembling chainmail. Structural studies of complexes between the bacteriophage MS2 and variants of its translational operator are also included in this work. A dimer of the MS2 coat protein binds with sequence specificity to an operator in its genomic RNA, and causes translational repression. Structures of multiple RNA segments with altered sequence at some positions which are required for binding to the capsid protein, has been determined.

This essay aims to study how national tests in the ninth grade are being viewed upon in the Swedish school system. What are the affected people’s thoughts regarding its field of application? For further information about this matter, three different sub studies have taken place. In the first sub study, literature from The Swedish National Agency for Education (SNAE) has been studied and compared to other researches. In the second sub study, pupils who took part in the national tests during the previous year answered a survey about their experiences working with the tests. The third sub study includes interviews with 12 teachers who all work with national tests in the ninth grade. These teachers were asked questions about their experiences working with the national tests. Results from the three sub studies are discussed thoroughly and are being brought together through a neo-rationalistic perspective in the discussion part of the essay. The major conclusion made is that there is a difference between the guidelines given by SNAE and how the affected people within the schools look upon the test system.

This paper is concerned with the problem of constructing A-optimal design for polynomial regression with analytic weight function on the interval [m-a,m+a]. It is shown that the structure of the optimal design depends on a and weight function only, as a close to 0. Moreover, if the weight function is an analytic function a, then a scaled version of optimal support points and weights is analytic functions of a at $a=0$. We make use of a Taylor expansion which coefficients can be determined recursively, for calculating the A-optimal designs.

This paper is devoted to studying the problem of constructing Ds-optimal design for d-th degree polynomial regression with analytic weight function on the interval [m-a,m+a],m,a in R. It is demonstrated that the structure of the optimal design depends on d, a and weight function only, as a close to 0. Moreover, the Taylor polynomials of the scaled versions of the optimal support points and weights can be computed via a recursive formula.

A mixture experiment is an experiment in which the k ingredients are nonnegative and subject to the simplex restriction £Ux_i=1 on the (k-1)-dimensional probability simplex S^{k-1}. This dissertation discusses optimal designs for linear and quadratic log contrast models for experiments with mixtures suggested by Aitchison and Bacon-Shone (1984), where the experimental domain is restricted further as in Chan (1992). In this study, firstly, an essentially complete class of designs under the Kiefer ordering for linear log contrast models with mixture experiments is presented. Based on the completeness result, £X_p-optimal designs for all p, -¡Û<p≤1 including D- and A-optimal are obtained, where the eigenvalues of the design moment matrix are used. By using the approach presented here, we gain insight on how these £X_p-optimal designs behave. Following that, the exact N-point D-optimal designs for linear log contrast models with three and four ingredients are further investigated. The results show that for k=3 and N=3p+q ,1 ≤q≤2, there is an exact N-point D-optimal design supported at the points of S_1 (S_2) with equal weight n/N, 0≤n≤p , and puts the remaining weight (N-3n)/N uniformly on the points of S_2 (S_1) as evenly as possible, where S_1 and S_2 are sets of the supports of the approximate D-optimal designs. When k=4 and N=6p+q , 1 ≤q≤5, an exact N-point design which distributes the weights as evenly as possible among the supports of the approximate D-optimal design is proved to be exact D-optimal. Thirdly, the approximate D_s-optimal designs for discriminating between linear and quadratic log contrast models for experiments with mixtures are derived. It is shown that for a symmetric subspace of the finite dimensional simplex, there is a D_s-optimal design with the nice structure that puts a weight 1/(2^{k-1}) on the centroid of this subspace and the remaining weight is uniformly distributed on the vertices of the experimental domain. Moreover, the D_s-efficiency of the D-optimal design for quadratic model and the design given by Aitchison and Bacon-Shone (1984) are also discussed Finally, we show that an essentially complete class of designs under the Kiefer ordering for the quadratic log contrast model is the set of all designs in the boundary of T or origin of T . Based on the completeness result, numerical £X_p -optimal designs for some p, -¡Û<p≤1 are obtained.

Au coeur des liens entre Théorie de la Démonstration et Théorie des Types, la correspondance de Curry-Howard fournit des termes de preuves aux aspects calculatoires et équipés de théories équationnelles, i.e. des notions de normalisation et d'équivalence. Cette thèse contribue à étendre son cadre à des formalismes (comme le calcul des séquents) appropriés à des considérations d'ordre logique comme la recherche de preuve, à des systèmes expressifs dépassant la logique propositionnelle comme des théories des types, et aux raisonnements classiques plutôt qu'intuitionistes.<br />La première partie est intitulée Termes de Preuve pour la Logique Intuitioniste Implicationnelle, avec des contributions en déduction naturelle et calcul des séquents, normalisation et élimination des coupures, sémantiques en appel par nom et par valeur. En particulier elle introduit des calculs de termes de preuve pour le calcul des séquents depth-bounded G4 et la déduction naturelle multiplicative. Cette dernière donne lieu à un calcul de substitutions explicites avec affaiblissements et contractions, qui raffine la beta-réduction.<br />La deuxième partie, intitulée Théorie des Types en Calcul des Séquents, développe une théorie des Pure Type Sequent Calculi, équivalents aux Systèmes de Types Purs mais mieux adaptés à la recherche de preuve.<br />La troisième partie, intitulée Vers la Logique Classique, étudie des approches à la Théorie des Types classique. Elle développe un calcul des séquents pour une version classique du Système Fomega. Une approche à la question de l'équivalence de preuves classiques consiste à calculer les représentants canoniques de preuves équivalentes dans le cadre du Calcul des Structures.

This basic study was designed to explore the conceptualization of prejudice as a form of contextually controlled, derived, and arbitrarily applicable relational responding. Basic studies utilizing RFT methodologies have yielded examples of how stimulus functions of one set of stimuli, such as a stereotyped group, can transform the functions of another stimulus, such as an individual. Priming procedures, as contextual cues, have been used to affect prejudicial responding. Stimuli participating in relational frames have been shown to be sensitive to such priming procedures; however, the role of context in the priming of derived relational responses has not yet been established. In the present study, 11 participants were trained to respond to four 3-member equivalence classes, consisting of word-like stimuli, under the contextual control of two background colors. Participants then completed a single-word lexical decision task in which prime/target pairs, consisting of related and unrelated pairs, were presented with and without contextual cues. For participants who successfully completed the training phase, response latencies to identify related pairs were generally shorter than for pairs involving a neutral word. However, response latencies between related pairs and unrelated pairs, consisting only of previously trained stimuli, failed to meet statistically significant differentiation. Responses were also similar between contextually related and contextually unrelated word pairs. The results failed to indicate the presence of a contextually controlled semantic priming effect at a statistically significant level; however, these results do suggest the possible presence of an episodic priming effect.

We present a generic proof methodology to automatically prove correctness of design transformations introduced at the Register-Transfer Level (RTL) to achieve lower power dissipation in hardware systems. We also introduce a new algorithm to reduce switching activity power dissipation in microprocessors. We further apply our technique in a completely different domain of dynamic power management of Systems-on-Chip (SoCs). We demonstrate our methodology on real-life circuits. In this thesis, we address the dual problem of transforming hardware systems at higher levels of abstraction to achieve lower power dissipation, and a reliable way to verify the correctness of the afore-mentioned transformations. The thesis is in three parts. The first part introduces Instruction-driven Slicing, a new algorithm to automatically introduce RTL/System level annotations in microprocessors to achieve lower switching power dissipation. The second part introduces Dedicated Rewriting, a rewriting based generic proof methodology to automatically prove correctness of such high-level transformations for lowering power dissipation. The third part implements dedicated rewriting in the context of dynamically managing power dissipation of mobile and hand-held devices. We first present instruction-driven slicing, a new technique for annotating microprocessor descriptions at the Register Transfer Level in order to achieve lower power dissipation. Our technique automatically annotates existing RTL code to optimize the circuit for lowering power dissipated by switching activity. Our technique can be applied at the architectural level as well, achieving similar power gains. We first demonstrate our technique on architectural and RTL models of a 32-bit OpenRISC pipelined processor (OR1200), showing power gains for the SPEC2000 benchmarks. These annotations achieve reduction in power dissipation by changing the logic of the design. We further extend our technique to an out-of-order superscalar core and demonstrate power gains for the same SPEC2000 benchmarks on architectural and RTL models of PUMA, a fixed point out-of-order PowerPC microprocessor. We next present dedicated rewriting, a novel technique to automatically prove the correctness of low power transformations in hardware systems described at the Register Transfer Level. We guarantee the correctness of any low power transformation by providing a functional equivalence proof of the hardware design before and after the transformation. Dedicated rewriting is a highly automated deductive verification technique specially honed for proving correctness of low power transformations. We provide a notion of equivalence and establish the equivalence proof within our dedicated rewriting system. We demonstrate our technique on a non-trivial case study. We show equivalence of a Verilog RTL implementation of a Viterbi decoder, a component of the DRM System-On-Chip (SoC), before and after the application of multiple low power transformations. We next apply dedicated rewriting to a broader context of holistic power management of SoCs. This in turn creates a self-checking system and will automatically flag conflicting constraints or rules. Our system will manage power constraint rules using dedicated rewriting specially honed for dynamic power management of SoC designs. Together, this provides a common platform and representation to seamlessly cooperate between hardware and software constraints to achieve maximum platform power optimization dynamically during execution. We demonstrate our technique in multiple contexts on an SoC design of the state-of-the-art next generation Intel smartphone platform. Finally, we give a proof of instruction-driven slicing. We first prove that the annotations automatically introduced in the OR1200 processor preserve the original functionality of the machine using the ACL2 theorem prover. Then we establish the same proof within our dedicated rewriting system, and discuss the merits of such a technique and a framework. In the context of today's shrinking hardware and mobile internet devices, lowering power dissipation is a key problem. Verifying the correctness of transformations which achieve that is usually a time-consuming affair. Automatic and reliable methods of verification that are easy to use are extremely important. In this thesis we have presented one such transformation, and a generic framework to prove correctness of that and similar transformations. Our methodology is constructed in a manner that easily and seamlessly fits into the design cycle of creating complicated hardware systems. Our technique is also general enough to be applied in a completely different context of dynamic power management of mobile and hand-held devices. / text

In an ever-changing world, people are constantly faced with the challenge of simultaneously managing multiple roles in their work as well as their home-sphere. It therefore becomes increasingly important to maintain a balance in these two life spheres. Unfortunately, a gap exists between the positive and negative side of work-home balance as most research focuses on the negative side. Recently, a much needed instrument was develop in the Netherlands, namely the Survey Work-Home Interaction - Nijmegen (SWING), which measures both the direction of influence (work→home and vice versa) and the quality of influence (negative vs. positive). The objectives of this study were to validate the Survey Work-Home Interaction - Nijmegen (SWING) for workers of the earthmoving equipment industry in a South African context, to determine its construct equivalence and bias for different language groups, and to determine differences regarding work-home interaction between different demographic groups. A cross-sectional survey design was used. Random samples (n = 330) were taken of workers in the earthmoving equipment industry across South Africa. The SWING and a biographical questionnaire were administered. Item bias analyses, exploratory factor analysis, Cronbach alpha coefficients, MANOVAs, ANOVAs and T-tests were used to analyse the data. Exploratory factor analysis showed that the SWING consists of four factors, namely Negative Work-Home Interference, Negative Home-Work Interference, Positive Work-Home Interference and Positive Home-Work Interference. All four factors showed acceptable internal consistencies. No evidence was found for uniform or non-uniform bias of the items of the SWING for different language groups. Exploratory factor analysis with target rotations confirmed the construct equivalence of the work-home interface construct. There were also no differences regarding work-home interaction between different demographic groups, except for a practically significant difference (medium effect) between males and females with respect to negative Work-Home Interaction levels. Recommendations were made for further research. / Thesis (M.Com. (Industrial Psychology))--North-West University, Potchefstroom Campus, 2005.

Les systèmes de planification dosimétrique utilisent pour calculer le dépôt de dose dans l'être humain d'une part une description des tissus basée sur l'imagerie scanographique et d'autre part une description de l'interaction du faisceau reposant sur une équivalence eau des tissus, à laquelle peut s'ajouter un facteur de diffusion. Du fait du type de rayonnement et de l'énergie utilisés en scanographie, les nombres CT doivent être convertis en facteurs d'équivalence eau avant d'être utilisés par le système de planification.<br />Une détermination par simulation GEANT4 du facteur d'équivalence eau en fonction des nombres CT est proposée. Les facteurs de 77 tissus humains ont été déterminés pour un faisceau de protons de 135 MeV et de 12C de 290 MeV/A et comparés à ceux rapportés dans la littérature. Aux erreurs de détermination (<1.5%) s'ajoutent les incertitudes liées à l'acquisition des nombres CT, ces dernières pouvant atteindre 2%.<br />Les facteurs d'équivalence eau ont ensuite été utilisés pour convertir les courbes d'énergie déposée obtenues dans un tissu à celles obtenues dans l'eau et inversement. Ces courbes d'énergie déposée recalées ont été comparées aux courbes d'énergie déposée issues de la simulation. Pour les deux faisceaux, un accord en position inférieur à 0.5 mm est atteint. Des différences selon les tissus apparaissent au niveau de l'énergie maximale déposée. Elles peuvent atteindre 3% pour les tissus osseux et le faisceau de protons et varient entre 1.5% et 3.5% pour le faisceau de 12C, quel que soit le tissu. Une amélioration significative des recalages de l'énergie déposée en deux dimensions est obtenue en introduisant un facteur supplémentaire permettant de corriger de la diffusion.