6,652 research outputs found
Cholesky decomposition of two-electron integrals in quantum-chemical calculations with perturbative or finite magnetic fields using gauge-including atomic orbitals
No full textA rigorous analysis is carried out concerning the use of Cholesky decomposition (CD) of two-electron integrals in the case of quantum-chemical calculations with finite or perturbative magnetic fields and gauge-including atomic orbitals. We investigate in particular how permutational symmetry can be accounted for in such calculations and how this symmetry can be exploited to reduce the computational requirements. A modified CD procedure is suggested for the finite-field case that roughly halves the memory demands for the storage of the Cholesky vectors. The resulting symmetry of the Cholesky vectors also enables savings in the computational costs. For the derivative two-electron integrals in case of a perturbative magnetic field we derive CD expressions by means of a first-order Taylor expansion of the corresponding finite magnetic-field formulas with the field-free case as reference point. The perturbed Cholesky vectors are shown to be antisymmetric (as already proposed by Burger et al. [J. Chem. Phys. 155, 074105 (2021)]) and the corresponding expressions enable significant savings in the required integral evaluations (by a factor of about four) as well as in the actual construction of the Cholesky vectors (by means of a two-step procedure similar to the one presented by Folkestad et al. [J. Chem. Phys. 150, 194112 (2019)] and Zhang et al. [J. Phys. Chem. A 125, 4258–4265 (2021)]). Numerical examples with cases involving several hundred basis functions verify our suggestions concerning CD in case of finite and perturbative magnetic fields
Die stil avontuur an evaluation of Hendrik Hofmeyr's song-cycle with an emphasis on the poetry of Elisabeth Eybers
No full textIncludes bibliographical references.Forty-six opuses in Hofmeyr's oeuvre are either inspired by or set to Afrikaans texts. This is indicative of his love for the language and of the culture in which he feels most comfortable. Of these works, the Afrikaans song is the most predominant genre which spans his entire compositional career. However, only one cycle, Alleenstryd, has been the subject of extensive academic evaluation (Roos, 2000; May, 2003; Cupido, 2010). For the purposes of this dissertation, I have decided to investigate Die stil avontuur, a cycle based on seven poems by Elisabeth Eybers. Die stil avontuur, commissioned by Lina Spies in celebration of Eybers' ninetieth birthday traces, like Robert Schumann's Frauenlieben und -leben, the life of a woman from the first meeting of her beloved to his death. My motivation for selecting this cycle as the subject for my study, besides considering it a high-point in both Hofmeyr's oeuvre and South African song, is one of identifying a number of correlations between Eybers and Hofmeyr. Both being recipients of international awards for their respective arts, they also both left their birth country in self-imposed exile. Another aspect common to both artists is their struggle to reconcile aspects of their upbringing with their arts
Nederlandse moslims : Van migrant tot burger (met cd-rom)
No full textDe moslims in de Nederlandse samenleving zijn onderwerp van debat, ook onder moslims zelf. De aanslagen van 9-11 en de moord op Van Gogh hebben veel emoties losgemaakt en vragen opgeroepen, vooral over de radicalisering van kleine groepen moslims, hun banden met de islamitische wereld, de rol van imams, de man-vrouw verhoudingen en de integratie van jongeren. Nederlandse moslims: van migrant tot burger gaat over migratie en intergratie, islamitische organisaties en geloofsbeleving, jongerencultuur en het islamdebat. De auteurs bekijken welke rol religieuze en andere waarden spelen en hoe deze veranderen. In kaderteksten wordt ingegaan op specifieke kwesties die vaak met de islam geassocieerd worden. In dertien beschrijvende profielen worden moslim-mannen en -vrouwen die optreden in het publieke debat beschreven. Als aanvulling bevat het boek een cd-rom met geluids- en videofragmenten met onder meer Hirsi Ali en Ali B. Daarnaast krijgt de lezer een kijkje in een moskee. Nederlandse moslims is een prikkelend themaboek, geschreven als leidraad voor iedereen die een genuanceerd oordeel wil vormen in het debat over moslims in Nederland
Author Co-Citation Analysis (ACA): a powerful tool for representing implicit knowledge of scholar knowledge workers
No full textIn the last decade, knowledge has emerged as one of the most important and valuable organizational assets. Gradually this importance caused to emergence of new discipline entitled ―knowledge management‖. However one of the major challenges of knowledge management is conversion implicit or tacit knowledge to explicit knowledge. Thus Making knowledge visible so that it can be better accessed, discussed, valued or generally managed is a long-standing objective in knowledge management. Accordingly in this paper author co- citation analysis (ACA) will be proposed as an efficient technique of knowledge visualization in academia (Scholar knowledge workers)
NMR Chemical Shift Computations at Second-Order M{\o}ller-Plesset Perturbation Theory Using Gauge-Including Atomic Orbitals and Cholesky-Decomposed Two-Electron Integrals
No full textWe report on a formulation and implementation of a scheme to compute NMR
shieldings at second-order Moller-Plesset (MP2) perturbation theory using
gauge-including atomic orbitals (GIAOs) to ensure gauge-origin independence and
Cholesky decomposition (CD) to handle unperturbed as well as perturbed
two-electron integrals. We investigate the accuracy of the CD for the
derivatives of the two-electron integrals with respect to an external magnetic
field as well as for the computed NMR shieldings, before we illustrate the
applicability of our CD based GIAO-MP2 scheme in calculations involving up to
about one hundred atoms and more than one thousand basis functions.Comment: 12 pages, 2 figure
Portfolio of recorded performances and exegesis: Messiaen’s musical language for the jazz pianist - an exploration through performance.
No full textMoving beyond Gunther Schuller’s Third Stream amalgamation of classical and jazz, this study explores whether the musical language of Olivier Messiaen can make a valid contribution to jazz piano performance. Initially, my project sought to answer such questions as: What elements of the musical language of Messiaen already exist in the jazz vocabulary? Am I able to extend this further? What are the timbral structures and pianistic effects within Messiaen’s musical language? What will be the most effective application of Messiaen’s musical language to jazz piano performance? Endeavouring to answer the final question led me to consider such aspects as whether the project should be limited to quoting Messiaen motifs, arranging Messiaen melodies, replacing jazz harmonic structures on standards with examples from Messiaen’s musical language or whether it would be better to approach the research conceptually. The work of Hubert Nuss provided encouraging reassurance that this was not an impossible task. In order to articulate this conception, the initial challenge was to decide how the classical and jazz worlds might meet in a ‘Messiaen’ technique. The approach adopted was similar to that used for undergraduate jazz study, namely, immersion in the piano scores and recordings of Messiaen’s music as well as by live performances. This was followed by the development and assessment of a contrived approach when specific techniques, such as tonal colourings or harmonic structures, were developed through prepared exercises and consciously included in my performance. It was then compared with an intuitive approach when no such precise parameters were established. This submission consists of CD recordings of two public recitals and an exegesis. It documents the development of this Messiaen technique and discusses its application in my performances. It also demonstrates the ways that Messiaen’s musical language can be used within jazz piano performance to provide a colour that distinguishes jazz piano performance in a competitive field.Thesis (M.Mus.) -- University of Adelaide, Elder Conservatorium of Music, 201
Even if only a song, contribute something of lasting value to your nation, Moerdyk's advice, Voortrekker monument will help create unity
No full text"Ons grootste nadeel is dat ons nog nie 'n nasie is nie", het mnr. Gerard Moerdijk, voorsitter van die Pretoriase Universiteitsraad en ontwerper van die Voortrekkermonument, vanaand gesê op die jaarlikse eetmaal van die Kollegetehuis van die Universiteit van Pretoria.At the yearly dinner of the Kollege hostel of the University of Pretoria, Gerard Moerdijk, architect of the Voortrekker monument, expressed his concern over the lack of a unified South African nation
Spinal anaesthesia for brachytherapy for carcinoma of the cervix a comparison of two dose regimes of hypebaric bupivacaine
No full textIncludes abstract.Includes bibliographical references.The main purpose of the study was to help establish the best dose regimen of hyperbaric bupivacaine, when combined with intrathecal fentanyl, for spinal anaesthesia for brachytherapy for carcinoma of the cervix. This procedure is performed as a day case at Groote Schuur Hospital
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