Semiclassical Limits of Extended Racah Coefficients

We explore the geometry and asymptotics of extended Racah coeffecients. The extension is shown to have a simple relationship to the Racah coefficients for the positive discrete unitary representation series of SU(1,1) which is explicitly defined. Moreover, it is found that this extension may be geometrically identified with two types of Lorentzian tetrahedra for which all the faces are timelike. The asymptotic formulae derived for the extension are found to have a similar form to the standard Ponzano-Regge asymptotic formulae for the SU(2) 6j symbol and so should be viable for use in a state sum for three dimensional Lorentzian quantum gravity.Comment: Latex2e - 26 pages, 6 figures. Uses AMS-fonts, AMS-LaTeX, epsf.tex and texdraw. Revised version with improved clarity and additional result

Engaged scholarship at the South African College of Music of the University of Cape Town: An exploratory study of the perceptions and practices of full-time music academic staff

Debates concerning the concept of 'engaged scholarship’ (ES) in terms of university-society connectivity have become part of the discourse within the shifting South African higher education landscape after 1994. Given the legacy of historical inequalities continuing to permeate all spheres of South African society including higher education, the idea of social-justice-centred engaged scholarship forms the main thrust of the narrative in this thesis. Furthermore, with music inherently geared towards societal engagement, and 'engaged scholarship’ included in UCT’s latest Social Responsiveness Policy Framework, this thesis critically examines the ES responses - in terms of their perceptions and practices - of music academics at the SACM in post-1994 South Africa. The opening chapter outlines the largely two-pronged research methodology approach pertaining to the analysis and findings of: (1) literature and documents, and (2) in-depth interviews of a representative sample of full-time SACM music academics. Chapter 2 provides a historical sociology unpacking the ES concept as part of an emergent University Third Mission. With developments largely unfolding at American universities, the first part of Chapter 2 shows the development of ES as essentially following two routes. Firstly the Triple Helix notion of university-industry-government (U-I-G) relations since the mid-20th century, identified by Etzkowitz as a 'Second Academic Transformation’ grafted on an earlier 19th century 'First Academic Transformation’ which began in Germany. Then secondly, in the 1990s a broadened view of scholarship aimed at making universities more relevant to the needs of society (i.e. via U-CS or university-civil society links) proposed by Boyer. With the issue of an emergent University Third Mission also entering the South African higher education discourse after 1994, the second part of Chapter 2 highlights conceptual confusion by considering policy and conference debates on 'community engagement’ (CE), the preferred expression for university-society relations in South Africa. Unfolding developments at UCT however have resulted in a discourse of ES becoming integral to this university’s Social Responsiveness Policy Framework after 2012. Moreover with social justice largely absent from CE discourse and the Triple Helix, Cooper has proposed a Quadruple Helix whereby civil society is added as fourth helix (i.e. resulting in U-I-G-CS). The approach of this study, therefore, explores the concept of a social-justice-centred engagement (outlined in part three of Chapter 2) with which it strongly resonates. Chapter 3 focuses attention on the milieu and ethos of UCT and the SACM, putting SACM music academics, part of an elite historically 'white’ university, in perspective. This highlights the entrenched hegemony of the historically 'white’ European settler institutional culture and 'orphan’ status of music indigenous to Africa at the SACM. Against this backdrop Chapter 4 provides a snapshot of the ES perceptions and practices of SACM music academics derived from the in-depth interviews. Importantly, with music largely absent from ES discourse, including at UCT, the critical analysis of the narratives of music academics form the basis for this thesis creating four music-specific ES categories in this chapter, and a proposed typology of music-specific ES in Chapter 5. In addition, a particularly important finding in Chapter 5 depicts the SACM as probably the most engaged UCT department, mainly displaying elements of the Quadruple Helix (U-I-G-CS), but with this engagement significantly skewed towards largely 'white’ civil society. Moreover, given the historically Eurocentric ethos of the SACM, western classical music has retained its uncontested hegemony (including within the SACM student curriculum) despite the introduction in the 1980s of new streams of non-western classical music, including music indigenous to Africa. With reference to ES, the engagement of the majority of SACM music academics was, furthermore, found overwhelmingly to be with the elite social classes. However, 'black’ academics were significantly more engaged with the 'black’ working class than their 'white’ counterparts. Considering the core findings above, pathways enabling the development of more balanced SACM-society relationships, particularly with the 'black’ working class majority have been proposed in the concluding chapter. A crucial recommendation is the decolonisation of the institutional culture and curriculum of the SACM, thereby restoring the former 'Other’, to 'Self’. These being spaces outside the comfort-zone of most music academics, it is suggested that music-specific ES research, potentially able to shift embedded reasoning, should become integral to the decolonisation process

Uniform electron gases: III. Low-density gases on three-dimensional spheres

By combining variational Monte Carlo (VMC) and complete-basis-set limit Hartree-Fock (HF) calculations, we have obtained near-exact correlation energies for low-density same-spin electrons on a three-dimensional sphere (3-sphere), i.e.~the surface of a four-dimensional ball. In the VMC calculations, we compare the efficacies of two types of one-electron basis functions for these strongly correlated systems, and analyze the energy convergence with respect to the quality of the Jastrow factor. The HF calculations employ spherical Gaussian functions (SGFs) which are the curved-space analogs of cartesian Gaussian functions. At low densities, the electrons become relatively localized into Wigner crystals, and the natural SGF centers are found by solving the Thomson problem (i.e. the minimum-energy arrangement of $n$ point charges) on the 3-sphere for various values of $n$. We have found 11 special values of $n$ whose Thomson sites are equivalent. Three of these are the vertices of four-dimensional Platonic solids --- the hyper-tetrahedron ($n=5$), the hyper-octahedron ($n=8$) and the 24-cell ($n=24$) --- and a fourth is a highly symmetric structure ($n=13$) which has not previously been reported. By calculating the harmonic frequencies of the electrons around their equilibrium positions, we also find the first-order vibrational corrections to the Thomson energy.Comment: 6 pages, 2 figures, accepted for publication in the Journal of Chemical Physic

3. A Ceylon Embassy to Egypt

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Basis functions for electronic structure calculations on spheres

We introduce a new basis function (the spherical gaussian) for electronic structure calculations on spheres of any dimension $D$. We find \alert{general} expressions for the one- and two-electron integrals and propose an efficient computational algorithm incorporating the Cauchy-Schwarz bound. Using numerical calculations for the $D = 2$ case, we show that spherical gaussians are more efficient than spherical harmonics when the electrons are strongly localized.Comment: 11 pages, 1 figure, accepted for publication in the Journal of Chemical Physic

Comparison of lung ultrasound with transpulmonary thermodilution in assessing extra-vascular lung water

Background: Increased extra-vascular lung water (EVLW) is common in critical care and correlates with the severity of acute lung injury, length of intensive care unit stay and mortality. Lung ultrasound (LUS) can assess EVLW by determining the amount of ‘B-lines’: artefacts signifying alveolar-interstitial oedema. This study’s aim was to determine whether EVLW estimation with the help of LUS correlates with the more accurate PiCCO2® cardiac output system utilising transpulmonary thermodilution.Methods: This prospective observational study was undertaken at Universitas Academic Hospital, Bloemfontein. Patients were scanned according to a fixed protocol, followed by transpulmonary thermodilution. The cumulative B-line count was compared with the EVLW index generated by the PiCCO2® system.Results: Four males and six females were enrolled. The mean EVLW index was 9.1 ml/kg/m2 (standard deviation 1.45), and the median cumulative B-line count was 14 (interquartile range 6–25). A positive, but not statistically significant, correlation was found (r = 0.40, p = 0.25) between the B-line count and EVLW index.Conclusion: This study investigated a possible correlation between LUS interpretation and transpulmonary thermodilution in assessing EVLW. Results seem promising, but the small sample could indicate only that LUS might be of use for the assessment of EVLW. Further studies are needed.Keywords: B-lines,critical care, extra-vascular lung water, lung ultrasound, thermodilutio

How players exploit variability and regularity of game actions in female volleyball teams

Variability analysis has been used to understand how competitive constraints shape different behaviours in team sports. In this study, we analysed and compared variability of tactical performance indices in players within complex I at two different competitive levels in volleyball. We also examined whether variability was influenced by set type and period. Eight matches from the 2012 Olympics competition and from the Portuguese national league in the 2014–2015 season were analysed (1496 rallies). Variability of setting conditions, attack zone, attack tempo and block opposition was assessed using Shannon entropy measures. Magnitude-based inferences were used to analyse the practical significance of compared values of selected variables. Results showed differences between elite and national teams for all variables, which were co-adapted to the competitive constraints of set type and set periods. Elite teams exploited system stability in setting conditions and block opposition, but greater unpredictability in zone and tempo of attack. These findings suggest that uncertainty in attacking actions was a key factor that could only be achieved with greater performance stability in other game actions. Data suggested how coaches could help setters develop the capacity to play at faster tempos, diversifying attack zones, especially at critical moments in competition

Mass and low-lying levels of 106,108In from the 106,108Cd(p,nγ) reactions

106In has been studied via the reaction 106Cd(p,nγ)106In in the energy range Ep=7-9 MeV. Inbeam γ-ray excitation functions, γ-γ coincidence measurements, and β+-delayed γ-ray excitation functions have been used to identify thirteen levels in 106In. From this new level scheme the energy separation of the high-spin ground state and the low-spin isomer has been determined to be 28.6±0.5 keV. The threshold energy of the strongest low-lying γ-ray transition yields a mass excess for 106In of -80601±15 keV. Spins for some states are suggested by comparing the excitation functions to Hauser-Feshbach calculations. In-beam γ-ray excitation functions for the 108Cd(p,nγ)108In reaction give a mass excess for the 3+ β+-decaying state in 108In of -84018±12 keV. The systematics of odd-odd In nuclei are discussed in a j-j coupling model

Measurement of the 7Be(p, γ)8B reaction cross section at low energies

The absolute total cross section for the reaction 7Be(p, γ)8B has been measured for Ec.m.=117-1230 keV by detecting the delayed α particles following the 8B β decay. Two independent methods have been used to determine the areal density of the 7Be target. The inferred zero-energy S factor from the present experiment is S17(0)=0.0216±0.0025 keV b. This value reduces the predicted 37Cl solar-neutrino capture rate by ∼25%