Call number: LD2668 .T4 1959 P57

Progress in the description of stellar evolution is driven by the collaborative effort of nuclear physics, astrophysics and astronomy. Using those developments, the theory of the origin of elements in the Universe is challenged. This thesis addresses the problem behind the abundance of 44Ti and the origin of 26Al. The mismatch between the predicted abundance of 44Ti as produced by the only sites known to be able to create 44Ti, core collapse supernovae (CCSNe), and the observations, highlight the current uncertainty that exists in the physics of these stars. Several satellite based γ-ray observations of the isotope 44Ti have been reported in recent times and confirm the disagreement. As the amount of this isotope in stellar ejecta is thought to critically depend on the explosion mechanism, the ability to accurately model the observed abundance would be a pivotal step towards validating that theory. The most influential reaction to the amount of 44Ti in supernovae is 44Ti(α, p)47V. Here we report on a direct study of this reaction conducted at the REX-ISOLDE facility, CERN. The experiment was performed at a centre of mass energy 4.15±0.23 MeV, which is, for the first time, well within the Gamow window for core collapse supernovae. The experiment employed a beam of 44Ti extracted from highly irradiated components of the SINQ spallation neutron source of the Paul Scherrer Institute. No yield above background was observed, enabling an upper limit for the rate of this reaction to be determined. This result is below expectation, suggesting that the 44Ti(α, p)47V reaction proceeds more slowly than previously thought. Implications for astrophysical events, and remnant age, are discussed. In Wolf-Rayet and asymptotic giant branch (AGB) stars, the 26gAl(p,γ)27Si reaction is expected to govern the destruction of the cosmic γ-ray emitting nucleus 26Al. The rate of this reaction, however, is highly uncertain due to the unknown properties of several resonances in the temperature regime of hydrogen burning. We present a high-resolution inverse kinematic study of the 26gAl(d, p)27Al reaction as a method for constraining the strengths of key astrophysical resonances in the 26gAl(p,γ)27Si reaction. In particular, the results indicate that the resonance at Er = 127 keV in 27Si determines the entire 26gAl(p, γ)27Si reaction rate over almost the complete temperature range of Wolf-Rayet stars and AGB stars. The measurements of spectroscopic factors for many states in 27Al and a shell model calculation of nuclear properties of rp-resonant states in 27Si also allow for testing the structure model.

Depuis son apparition, le logiciel T-Rex (tree and reticulogram recontruction) est un outil puissant pour la reconstruction et la visualisation d'arbres phylogénétiques et de réticulogrammes. Un réticulogramme est un réseau phylogénétique permettant de représenter les phénomènes d'évolution réticulée tels que l'hybridation, la recombinaison génétique et le transfert latéral de gènes. La reconstruction peut être faite à partir des matrices de distances complètes, des matrices de distances incomplètes et des séquences moléculaires. Dans le but de permettre aux biologistes et aux bioinformaticiens de bénéficier des différentes options, modes de calcul, ainsi que des diverses nouveautés de T-Rex, nous avons développé la version Web de ce logiciel. Dans ce mémoire, nous décrivons les différentes fonctions, méthodes et outils inclus dans T-Rex Web. Nous décrivons aussi les nouveaux programmes ajoutés à T-Rex Web, tels que ClustalW, Calcul de la distance topologique de Robinson et Foulds, et Species Taxonomy. La dernière option permet de générer une matrice de distances d'arbre et de reconstruire des arbres phylogénétiques à partir des listes des lignées des espèces données. La version Web du logiciel T-Rex est disponible à l'adresse URL suivante: www.trex.uqam.ca. ______________________________________________________________________________ MOTS-CLÉS DE L’AUTEUR : T-Rex, arbre phylogénétique, matrice de distance, réticulogramme, interface Web, taxonomie d'espèces.

abstract: Peter N. Schubert in "Hidden Forms in Palestrina's `First Book of Four-Voice Motets'" (Journal of the American Musicological Society, 2007) defines significant blocks of vertical relationships in imitative and non-imitative duos in the thirty-six motets of Palestrina's Motectus festorum totius anni cum communi sanctorum, published in 1564. Schubert describes these blocks of vertical relationships that proceed from duos as modules and organizes them according to categories of construction and function. Palestrina's parody Mass, O Rex glóriæ, reveals the same duos and modules that Schubert discovers in Palestrina's motet of the same name. Palestrina transfers these duos and modules from the motet into the parody Mass, using them as building blocks for points of imitation. The duos, modules, and their motives appear in all but a few places, and are in some cases prominent throughout movements of the Mass, such as the Kyrie. Palestrina manipulates and elaborates these duos and modules according to the character and text of each movement. He borrows them consistently in their original order, which he changes only for reasons of textual meaning or verbal similarity. The module approach to recurring vertical combinations, although a recent application, is valuable for recognizing and treating systematically the duo relationships and their elaboration that are described by late-Renaissance theorists, especially Fray Tomas de Sancte Maria. The identification and analytical interpretation of duos and modules in Palestrina's motet O Rex glóriæ and the parody Mass based on it yields insights not only into his compositional decisions as he adapts material from the motet for its new setting, but also into the potential value of modules as the basis for an analytical approach to the sacred vocal polyphony of the sixteenth century. / Dissertation/Thesis / M.A. Music 2013

No description available.

Les institutions de la République romaine (509-27 av. J. C.) prévoyaient théoriquement que les magistratures électives et annuelles ne devaient jamais être vacantes. Ce principe juridique fondamental avait pour conséquence une continuité dans la détention du pouvoir exécutif qui reposait sur le ius, les auspicia et l'imperium. Cependant, il arriva à maintes reprises que les magistratures supérieures - consulat, tribunat militaire à pouvoir consulaire - fussent suspendues en raison soit d'entrave à la tenue des comices électoraux soit de scrupules religieux entraînant l'expiation rituelle et la renouatio auspiciorum. La légitimité et la légalité de la solution à la vacance du pouvoir exécutif reposait alors sur les patres auctores, détenteurs de l'auspicia patrum. Le rite de l'interregnum, procédure juridique archaïque, était l'émanation la plus claire de cette auctoritas patrum, apanage exclusif des sénateurs patriciens. Les vénérables pères, descendants des plus illustres familles de Rome, étaient les seuls à même de remédier à la vacance des magistratures par ce rite qui remontait, d'après la tradition, à l'époque royale latino-sabine et renvoyait au mythe bien connu du démembrement et de l'apothéose de Romulus. Le partage du corps souverain constitue à ce titre un symbole fondamental pour la représentation de l'auctoritas patrum et de la magistrature républicaine dont il serait peut-être vain de rechercher l'historicité. L'objet de cette étude est donc d'analyser la fort ancienne institution de l'interregnum qui, comme bien d'autres, était caractérisée par un passage progressif du sacral au juridique. Le droit public prévoit dans tout système institutionnel des recours d'exception révélant la représentation psychologique du pouvoir souverain. Rome n'échappe pas à la règle voire même elle put, d'une certaine façon, l'inventer.

Bacillus cereus est une bactérie très largement disséminée dans l'environnement. Certaines souches sont à l'origine de toxi-infections alimentaires de type émétique ou diarrhéique. Afin de coloniser l'intestin et induire un syndrome diarrhéique, B. cereus doit s'adapter aux variations d'oxygénation et de potentiel d'oxydoréduction rencontrées, se multiplier et sécréter des toxines. En comparant les capacités métaboliques et les capacités de sécrétion de l'entérotoxine Nhe de quatre souches de B. cereus, nous avons mis en évidence que la L-lactate déshydrogénase A (LdhA) était quelles que soient les conditions de croissance impliquée à la fois dans le métabolisme fermentaire et dans la toxinogénèse de B. cereus. LdhA contribue au maintien du ratio NAD+/NADH intracellulaire et son absence affecte les capacités d'expression de plusieurs gènes d'entérotoxines en anaérobiose et en aérobiose chez la souche F4430/73. Afin de déterminer si l'effet observé sur les toxines était indirect et dépendant du régulateur rédox Rex, un mutant ne synthétisant plus Rex a été construit. La caractérisation de ce mutant a mis en évidence le rôle de Rex dans le métabolisme de B. cereus, dans la réponse au stress oxydant et dans la toxinogénèse. De part sa structure et sa capacité a lié l'ADN, Rex pourrait être un facteur de transcription contrôlant l'expression des gènes codant les entérotoxines. Sa capacité de fixation sur l'ADN est dépendante du ratio NAD+/NADH. Afin de déterminer si LdhA pouvait réguler directement l'expression des gènes des toxines, ldhA a été exprimé chez E. coli et purifiée sous la forme d'une protéine fusion. Les premières expériences de retard sur gel n'ont pas permis de mettre en évidence de fixation sur les régions promotrices de toxines / Bacillus cereus is a widespread bacteria. Some strains are responsible of food-borne classified as emetic and diarrhoel syndromes. To colonize such environment and induce diarrhea, B. cereus must be able to grow in the various oxidoreduction potential and oxygenation conditions encountered in the gastrointestinal tract and to secrete toxins. By comparing the catabolic capacities of four strains of the B. cereus group grown under anoxic and oxic conditions in relation to their capacities for expressing Non hemolytoc enterotoxin (Nhe), we identified Lactate dehydrogenase A (LdhA) as both involved in the fermentative metabolism of B. cereus and toxinogenesis. We showed that disruption of ldhA affected the fermentative capacity of anaerobically grown F4430/73 cells and the expression of several enterotoxin genes under both anaerobiosis and aerobiosis. To determine whether the observed effect in the toxins expression was indirect and dependant of Rex, a rex mutant was built. The characterization of this mutant revealed the role of Rex in the metabolism of B. cereus, oxidative stress and toxins production. Rex could be a transcription factor controlling the expression of genes encoding enterotoxins. Ability of DNA binding is dependant on the ratio of NAD+/NADH. To determine whether LdhA could directly regulate the expression of toxins genes, LdhA was expressed in E. coli and purified as a fusion protein. The first gel retardation experiments have failed to demonstrate fixation of LdhA in the promoter regions of toxins

Size comparisons, skeletochronological, and palaeohistological studies have been major contributors in the past decades to expand our knowledge on how dinosaurs, including Tyrannosaurus rex, lived and grew. Historically, size comparisons have been used to establish a relative order of age, and thin sections have been used to study the palaeohistology and skeletochronology, as well as establish growth curves, to construct more quantifiable age determinants. Whenever a new specimen is found or described, it should be placed in context by comparing it to the other known specimens. This study aims to do that for the Naturalis T. rex specimen, RGM 792.000. Comparing the femoral length and circumference data places RGM 792.000 3rd to 6th in size, depending on the literature cited, and so it can be concluded that this T. rex is a, younger, adult. The palaeohistological side of this study aims to reconstruct a more exact age at the time of death as well as a growth curve, using not only thin sections, but also synchrotron radiation computed microtomography. By counting the lines of arrested growth through both methods it can be established that RGM 792.000 was at least 17 years old at the time of death. Additionally, this study demonstrates that the use of synchrotron scans is beneficial to use as a complementary method when studying the skeletochronology and palaeohistology in dinosaurs. / Hur gammal kunde Tyrannosaurus rex bli? Trots sin ikoniska status finns det mycket vi fortfarande inte vet om T. rex men med varje ny upptäckt kommer en ökad förståelse och Naturalis-provet, också kallat RGM 792.000 eller Trix, är inte ett undantag. Genom att jämföra storleken på olika individer, kan vi säga något om deras relativa ålder och tack vare det vet vi att Trix var en ung vuxen. Men för att ta reda på exakt hur gammal en individ av T. rex var, har forskare hittills varit tvugna att göra tvär- och tunnsnitt i ben för att räkna de tillväxtringar som ofta bevaras trots fossilisering. Eftersom dessa metoder delvis förstör fossilen har nya skanningtekniker, såsom synkrotron-mikrotomografi, börjat tillämpats. I denna studie har både tunnsnitt samt synkrotronskanningar analyserats och tillsammans visar de på att Trix var minst 17 år gammal när den dog. De båda metoderna kompletterar varandra och kan med fördel användas tillsammans för att göra en robust åldersbestämning.

Study project (MBA)--University of Stellenbosch, 2002. / ENGLISH ABSTRACT: The one factor in the current business environment that provides an organisation with a competitive advantage, is human capital. It can make the difference between success and failure. In an organisation like Rex Mining it is especially important for a strong human capital base to meet the challenges that the marginal diamond mines present. It is not a question of finance. Human capital development is determined by the people management practices in an organisation, things they already do. The difference between building and breaking down human capital is just a matter of quality and appropriateness of these practices. The measurement of the ability of an organisation to develop human capital was always problematic because of the nature of it. Buckingham and Coffman developed an easy and valid measuring instrument to help organisations measure this very important factor. The questionnaire they developed now makes it possible for every organisation to make a determination of where it stands in terms of its ability to develop human capital. An investment in human capital will always give a return on the investment. The size of the return will be determined by the time and energy spend on the investment by the organisation. This investment does not depreciate. An investment in human capital will ensure optimal productivity, efficiency and effectiveness in the organisation and that targets will be reached and exceeded. Healthy people management practices are the basis upon which the development of human capital rests. In a changing South Africa different demands are made upon organisations in terms of their human capital. Each individual has his own goals and career plans and if the organisation cannot satisfy those demands the employee will offer his services to the employer that can satisfy his needs. / AFRIKAANSE OPSOMMING: Menslike kapitaal is in die hedendaaqse sakewêreld die een faktor wat aan 'n organisasie die kompeterende voordeel gee. Dit kan die verskil tussen sukses en mislukking bepaal. In 'n organisasie soos Rex Mining is dit juis belangrik dat menslike kapitaal sterk moet wees ten einde die geweldige uitdagings wat die marginale diamantmyne stel, die hoof te kan bied. Dit is ook nie 'n kwessie van finansies nie. Menslike kapitaalontwikkeling word bepaal deur die mensebestuurspraktyke in 'n organisasie, dinge wat elke organisasie reeds doen. Dit is net die kwaliteit en toepaslikheid van hierdie praktyke wat die verskil maak tussen die opbou en afbreek van menslike kapitaal. Die meting van die vermoë van 'n organisasie om menslike kapitaal te ontwikkel, was altyd problematies vanweë die aard daarvan. Buckingham en Coffman het egter 'n baie maklike en geldige meetinstrument daargestelom organisasies te help om hierdie baie belangrike faktor te meet. Die vraelys wat hulle ontwikkel het, maak dit nou moontlik vir elke organisasie om 'n bepaling te maak ten opsigte van die organisasie se vermoë om sy menslike kapitaal te ontwikkel. 'n Belegging in menslike kapitaal sal altyd 'n opbrengs lewer. Die grootte van die opbrengs sal afhang van die hoeveelheid tyd en energie wat die organisasie bestee het aan die belegging. Hierdie belegging verloor ook nooit sy waarde nie. 'n Belegging in die menslike kapitaal van 'n organisasie sal verseker dat produktiwiteit, effektiwiteit en doeltreffendheid optimaal sal wees en dat die organisasie altyd doelwitte sal behaal en oorskry. Gesonde mensebestuurspraktyke is die basis waarop die hele ontwikkeling van menslike kapitaal berus. In die veranderende Suid-Afrika word nuwe vereistes aan organisasies gestel in terme van hulle menslike kapitaal. Elke individu het sy eie doelwitte en loopbaanplanne en as die organisasie waar hy of sy werk, nie hieraan kan voldoen nie, sal die werknemer sy dienste aan 'n werkgewer bied wat wel sy behoeftes kan bevredig.

O texto da tragédia grega Édipo Rei de Sófocles, do século V a.C., permite até os dias de hoje inúmeros estudos sobre seu mito, face a tamanha riqueza existente em seu mitologema. Pressuposto a tantas pesquisas existentes, elaboramos uma visão inerente aos estudos realizados, compondo uma dissertação comparativa, revisitando o texto de Sófocles e incluindo uma nova ótica sobre a tragédia do rei de Tebas. Porém, antes de mergulharmos na essência do mito, procuramos entender a tragédia grega e seu período de existência. Da mesma forma, investigamos o homem Sófocles, artista e poeta na sociedade em que viveu, e suas relações sociais e políticas com seu amigo e estrategista Péricles. Ponto imprescindível da dissertação é a constatação de que Sófocles fundiu em um só personagem feminino a figura das duas esposas de Laio, condensadas em Jocasta. Tornada mãe e esposa de Édipo, o personagem de Jocasta aumentou profundamente o efeito dramático desejado pelo autor grego, criando um dos maiores textos trágicos da antiguidade que chegaram até hoje. Sem perder a essência do texto sofocliano, decodificamos o mito em suas diversas vertentes, situamos as condições sociais nas relações da mulher no século V a.C., e, assim, estabelecemos as relações que envolveram Édipo e Jocasta no conjunto poético da tragédia reelaborada por Sófocles. / The text of the Greek tragedy Oedipus Rex, by Sophocles, 5th century BC, allows us, until the present days, to make innumerous studies about its myth, due to the immense richness of its mythologem. Considering so many existing researches, we have elaborated a vision inherent to the studies already done, writing a comparative dissertation, revisiting Sophoclestext and throwing some new light upon the tragedy of the King of Thebes. However, before plunging into the essence of the myth, we have tried to understand the Greek tragedy and its existing context. In the same way, we have investigated the man Sophocles, artist and poet in the society he lived in, and his social and political relationship with his friend and strategist Pericles. The essential point of the dissertation is the thesis that Sophocles has melted, in a single feminine character, the profiles of the two wives of Laius, condensed in Jocasta. Transformed into mother and wife of Edipo, the character Jocasta deeply increased the dramatic effect desired by the Greek author, creating one of the greatest tragic text of antiquity that have arrived to present days. Without losing the essence of the sophoclean text, we have decoded the myth in its various aspects, contextualized the social conditions of the womens relations in the 5th century BC, and, finally, we have established the relations that involved Edipo and Jocasta in the poetic set of the tragedy re-elaborated by Sophocles.