Scattering of a Long Cosmic String by a Rotating Black Hole

The scattering of a straight, infinitely long string by a rotating black hole is considered. We assume that a string is moving with velocity v and that initially the string is parallel to the axis of rotation of the black hole. We demonstrate that as a result of scattering, the string is displaced in the direction perpendicular to the velocity by an amount kappa(v,b), where b is the impact parameter. The late-time solution is represented by a kink and anti-kink, propagating in opposite directions at the speed of light, and leaving behind them the string in a new ``phase''. We present the results of the numerical study of the string scattering and their comparison with the weak-field approximation, valid where the impact parameter is large, b/M >> 1, and also with the scattering by a non-rotating black hole which was studied in earlier works.Comment: 27 pages, 14 figures, to be published in Classical and Quantum Gravit

The integration of intrapreneurship into a performance management model.

This study aimed to investigate the feasibility of using the dynamics of intrapreneurship to develop a new generation performance management model based on the structural dynamics of the Balanced Score Card approach. The literature survey covered entrepreneurship, from which the construct, intrapreneurship, was synthesized. Reconstructive logic and Hermeneutic methodology were used in studying the performance management systems and the Balanced Score Card approach. The dynamics were then integrated into a new approach for the management of performance of intrapreneurial employees in the corporate environment. An unstructured opinion survey followed: a sample of intrapreneurship students evaluated and validated the model’s conceptual feasibility and probable practical value

A near-infrared study of the star forming region RCW 34

We report the results of a near-infrared imaging study of a $7.8 \times 7.8$ arcmin$^2$ region centered on the 6.7 GHz methanol maser associated with the RCW 34 star forming region using the 1.4m IRSF telescope at Sutherland. A total of 1283 objects were detected simultaneously in J, H, and K for an exposure time of 10800 seconds. The J-H, H-K two-colour diagram revealed a strong concentration of more than 700 objects with colours similar to what is expected of reddened classical T Tauri stars. The distribution of the objects on the K {\it vs} J-K colour-magnitude diagram is also suggestive that a significant fraction of the 1283 objects is lower mass pre-main sequence stars. We also present the luminosity function for the subset of about 700 pre-main sequence stars and show that it suggests ongoing star formation activity for about $10^7$ years. An examination of the spatial distribution of the pre-main sequence stars shows that the fainter (older) part of the population is more dispersed over the observed region and the brighter (younger) subset is more concentrated around the position of the O8.5V star. This suggests that the physical effects of the O8.5V star and the two early B-type stars on the remainder of the cloud out of which they formed, could have played a role in the onset of the more recent episode of star formation in RCW 34.Comment: Accepted for publication in The Astronomical Journa

A Numerical Method for General Relativistic Magnetohydrodynamics

This paper describes the development and testing of a general relativistic magnetohydrodynamic (GRMHD) code to study ideal MHD in the fixed background of a Kerr black hole. The code is a direct extension of the hydrodynamic code of Hawley, Smarr, and Wilson, and uses Evans and Hawley constrained transport (CT) to evolve the magnetic fields. Two categories of test cases were undertaken. A one dimensional version of the code (Minkowski metric) was used to verify code performance in the special relativistic limit. The tests include Alfv\'en wave propagation, fast and slow magnetosonic shocks, rarefaction waves, and both relativistic and non-relativistic shock tubes. A series of one- and two-dimensional tests were also carried out in the Kerr metric: magnetized Bondi inflow, a magnetized inflow test due to Gammie, and two-dimensional magnetized constant-$l$ tori that are subject to the magnetorotational instability.Comment: 37 pages, 14 figures, submitted to ApJ. Animations can be viewed at http://www.astro.virginia.edu/~jd5v/grmhd/grmhd.htm

Application of the Cubed-Sphere Grid to Tilted Black-Hole Accretion Disks

In recent work we presented the first results of global general relativistic magnetohydrodynamic (GRMHD) simulations of tilted (or misaligned) accretion disks around rotating black holes. The simulated tilted disks showed dramatic differences from comparable untilted disks, such as asymmetrical accretion onto the hole through opposing "plunging streams" and global precession of the disk powered by a torque provided by the black hole. However, those simulations used a traditional spherical-polar grid that was purposefully underresolved along the pole, which prevented us from assessing the behavior of any jets that may have been associated with the tilted disks. To address this shortcoming we have added a block-structured "cubed-sphere" grid option to the Cosmos++ GRMHD code, which will allow us to simultaneously resolve the disk and polar regions. Here we present our implementation of this grid and the results of a small suite of validation tests intended to demonstrate that the new grid performs as expected. The most important test in this work is a comparison of identical tilted disks, one evolved using our spherical-polar grid and the other with the cubed-sphere grid. We also demonstrate an interesting dependence of the early-time evolution of our disks on their orientation with respect to the grid alignment. This dependence arises from the differing treatment of current sheets within the disks, especially whether they are aligned with symmetry planes of the grid or not.Comment: 15 pages, 11 figures, submitted to Ap

Die meting van die verband tussen geslag en konformiteit as groepdinamiese veranderlikes

The original publication is available at http://www.sajip.co.zaThe amount and kind of conformity induced by group pressure depend upon the nature of the situation. The nature of the group and the characteristics of the individual. In this particular study the experimental measurement of conformity developed by Asch and Crutchfield was repeated. Confirmation was found that sex operates as one of the determinants of conformity.Publishers' Versio

Additive Main Effects and Multiplicative Interactions (AMMI) and genotype by environment interaction (GGE) biplot analyses aid selection of high yielding and adapted finger millet varieties

Background and justification: Lack of stable high yielding cultivars is one of the major bottlenecks for production and productivity of finger millets in Ethiopia. Identification of adaptable, stable and high yielding genotypes under varying environmental conditions prior to release as a cultivar is the first and foremost steps for plant breedingr and this has direct bearing on the adoption of the variety, its productivity and total production of the crop.Objective: The major objectives of the present study were to (i) assess the stability and yield performance of advanced finger millet genotypes  evaluated in multiple environments, and (ii) identify stable high yieldingcandidate cultivar (s) for possible release using different statistical tools.Material and methods: A total of 30 advanced finger millet genotypes were evaluated against two standard checks (Gute and Taddese) across four locations (Arsi Negele, Assosa, Bako and Gute) in 2012 and 2013 main cropping seasons. The trial was arranged in a randomized complete block design (RCBD) replicated three times.Summary result and application of the study: Additive Main effect and Multiplicative Interaction (AMMI), Genotype and Genotype by Environment interaction (GGE) biplot analysis and, Eberhart and Russellmodel revealed that Acc. 203544 is stable high yielding (3.16 ton ha-1) with a yield advantage of 13.7% over the best standard check, Gute (2.78 ton ha-1), and thus should be recommended for possible release with wider environmental adaptability. Acc. 242111 (3.08 ton ha-1), Acc. BKFM0051 (3.07 ton ha-1) and Acc.229738 (2.99 ton ha-1) were also high yielding, but showed narrow stability and thus should be recommended for verification and possible release for specific environments.Key words/phrases: Additive main effect and multiplicative interaction (AMMI), Finger millet (Eleusine coracana subsp. coracana), Genotype by Environment Interaction (GEI

Kurrikulumontwikkeling vir volhoubare sportbestuuropleiding in Suid-Afrika

Thesis (PhD (Education )--University of Stellenbosch, 2003.355 leaves printed on single pages, preliminary pages i- xxiii and numbered pages 1-330. Includes bibliography and list of tables. Digitized at 600 dpi grayscale to pdf format (OCR), using a Bizhub 250 Konica Minolta Scanner.ENGLISH ABSTRACT: The sporting environment in South Africa started changing drastically when professional sport increasingly became a reality after years of sporting isolation. As a result of these changes new career opportunities opened up because professionals were required to manage professional sport. These new professional sporting organisations are modelled on economically active businesses that require managers at all levels. Training institutions soon started offering programmes to train these so-called sports managers. Although there are specialists working in the sporting environment, the generic term "sports manager" is used to identify these individuals. The appropriate and sustainable training of sports managers forms the nucleus of the research in this study. Training programmes for sports managers are mostly offered at departments of human movement studies or sports science. This tended to create the impression that these training programmes are merely adapted human movement studies programmes that do not necessarily make provision for the professional sports management industry. The main purpose of this study was to design a curriculum framework for sport management training that is not only practice-oriented, but that also ensures sustainable programmes. To realise this, both an international and a national historical perspective on sport management training were researched. A description of a theoretical curriculum model with specific reference to current trends in education in South Africa was given. Furthermore it endeavoured to establish, from within the sporting industry, the knowledge and skills that are required for a career in sports management. From this information an attempt was made to suggest a curriculum framework so that appropriate and sustainable sports management training programmes can be offered. From a historical survey it became evident that sports management training programmes are in a relatively early development phase. An analysis of international programmes revealed that these programmes focus mainly on the economic and management activities in sports management organisations. Few instances were found where human movement studies constituted a prominent part of the contents of the programmes. However, the opposite was found to be true when South African programmes were reviewed. The majority of these programmes include components of human movement studies/sport science in their contents. Some of the programmes focus specifically on human movement studies/sport science and merely offer introductory modules on aspects of sports management. This study indicates the necessity for sports management training programmes in higher education to fit into specific structures in the South African education framework. New developments centred around the South African Qualifications Authority, the Higher Education Board and more specifically the National Qualifications Framework have been researched and applied to sports management training programmes. To place this study within the perspective of curriculum development, various models and methods of curriculum evaluation were explored. As a result of this a synoptic list was compiled to which sports management programmes may be required to comply. As part of the study a questionnaire review was conducted to indicate sports managers' knowledge and skills requirements in three levels of management. Guidelines were derived from this for generic contents of sports management programmes. It was also indicated that specialist functions exist within the sports management industry and that this phenomenon cannot merely be ignored by academic institutions when curricula are designed. These findings were used to suggest a possible framework for sports management curricula. In the light of a changing environment in South Africa and the development of the professional sports management industry, it is necessary that this framework should continuously be supplemented in a dynamic sporting environment.AFRIKAANSE OPSOMMING: Die sportbedryf het in Suid-Afrika drasties begin verander toe beroepsport na jare van sportisolasie toenemend 'n werklikheid geword het. Uit hierdie veranderinge het daar nuwe beroepsmoontlikhede ontstaan deurdat professionele persone nodig was om professionele sport te bestuur. Hierdie nuwe professionele sportorganisasies is op die lees van ekonomies-aktiewe besighede geskoei wat beteken dat bestuurders op aile vlakke benodig is. Opleidingsinstellings het spoedig begin om programme aan te bied vir die opleiding van hierdie sogenaamde sportbestuurders. Alhoewel daar 'n verskeidenheid spesialiste in die sportomgewing werk, word die generiese term "sportbestuurder" gebruik om hierdie persone te identifiseer. Die toepaslike en volhoubare opleiding van sportbestuurders vorm die kern van ondersoek in hierdie studie. Opleidingsprogramme vir sportbestuuropleiding word meestal in departemente van menslike bewegingskunde of sportwetenskap aangebied, wat die vermoede laat ontstaan het dat hierdie programme slegs aangepaste menslike bewegingskundeprogramme is en nie noodwendig vir die volle spektrum van behoeftes van die professionele sportbestuurbedryf voorsiening maak nie. Die hoofdoel van hierdie studie was die daarstelling van 'n kurrikulumraamwerk vir sportbestuuropleiding wat nie net praktykgerig is nie, maar ook die volhoubaarheid van hierdie programme verseker. Om dit te verwesenlik, is daar gepoog om 'n internasionale en nasionale historiese perspektief oor sportbestuuropleiding daar te stel. 'n Teoretiese kurrikulummodel is beskryf met spesifieke verwysing na huidige onderwystendense in Suid-Afrika. Vervolgens is gepoog om vanuit die sportbedryf te bepaal wat die kennis- en vaardigheidsvereistes is wat die sportbestuurberoep aan individue stel. Uit hierdie gegewens is gepoog om 'n kurrikulumraamwerk te ontwerp ten einde 'n bydrae te maak tot die volhoubare en toepaslike voorsiening van sportbestuuropleiding. Uit 'n historiese oorsig het dit geblyk dat sportbestuuropleidingsprogramme in 'n relatief vroeë ontwikkelingsfase verkeer. Wat uit die ontleding van internasionale programme duidelik geblyk het, is dat hierdie programme veral op die ekonomiese en bestuursaktiwiteite van sportbestuurorganisasies gefokus is. Min gevalle is aangetref waar menslike bewegingskunde 'n prominente deel van die programinhoud uitmaak. Daar is egter bevind dat die teendeel grootliks waar is van programme in Suid-Afrika. Die meerderheid van die programme het wel komponente van menslike bewegingskunde/sportwetenskap as deel van die inhoud. Sommige programme fokus spesifiek op menslike bewegingskunde/sportwetenskap en bied sportbestuuraspekte slegs as inleidende modules aan. Die studie toon aan dat dit noodsaaklik is om sportbestuuropleidingsprogramme in hoër onderwys binne spesifieke strukture in die Suid-Afrikaanse opvoedingsraamwerk in te pas. Ontwikkelinge rondom die Suid-Afrikaanse Kwalifikasie-owerheid, die Hoër Onderwysraad en meer spesifiek die Nasionale Kwalifikasieraamwerk is ondersoek in die lig van moontlike toepassings op sportbestuurprogramme. Om die studie binne die perspektief van kurrikulumontwikkeling te plaas, is ondersoek ingestel na verskillende modelle en metodes van kurrikulumevaluering. Hieruit is 'n oorsiglys waaraan sportbestuurprogramme moontlik beoordeel kan word, saamgestel. 'n Vraelysondersoek is benut ten einde kennis- en vaardigheidsvereistes van sportbestuurders op drie bestuursvlakke aan te toon. Riglyne ten opsigte van generiese inhoude vir sportbestuurprogramme is hieruit verkry. Daar is ook aangetoon dat spesialisfunksies binne die sportbestuurbedryf bestaan en dat hierdie verskynsel tydens kurrikulumontwerp nie sonder meer deur akademiese instellings geignoreer kan word nie. Hierdie bevindinge is gebruik om 'n moontlike raamwerk vir sportbestuurkurrikula voor te stel. In die lig van 'n veranderende samelewing in Suid-Afrika en die ontwikkeling van die professionele sportbestuurbedryf is dit noodsaaklik dat hierdie raamwerk in 'n dinamiese sportomgewing voortdurend aangevul word

Kurrikulumontwikkeling vir volhoubare sportbestuuropleiding in Suid-Afrika

Thesis (PhD (Education )--University of Stellenbosch, 2003.355 leaves printed on single pages, preliminary pages i- xxiii and numbered pages 1-330. Includes bibliography and list of tables. Digitized at 600 dpi grayscale to pdf format (OCR), using a Bizhub 250 Konica Minolta Scanner.ENGLISH ABSTRACT: The sporting environment in South Africa started changing drastically when professional sport increasingly became a reality after years of sporting isolation. As a result of these changes new career opportunities opened up because professionals were required to manage professional sport. These new professional sporting organisations are modelled on economically active businesses that require managers at all levels. Training institutions soon started offering programmes to train these so-called sports managers. Although there are specialists working in the sporting environment, the generic term "sports manager" is used to identify these individuals. The appropriate and sustainable training of sports managers forms the nucleus of the research in this study. Training programmes for sports managers are mostly offered at departments of human movement studies or sports science. This tended to create the impression that these training programmes are merely adapted human movement studies programmes that do not necessarily make provision for the professional sports management industry. The main purpose of this study was to design a curriculum framework for sport management training that is not only practice-oriented, but that also ensures sustainable programmes. To realise this, both an international and a national historical perspective on sport management training were researched. A description of a theoretical curriculum model with specific reference to current trends in education in South Africa was given. Furthermore it endeavoured to establish, from within the sporting industry, the knowledge and skills that are required for a career in sports management. From this information an attempt was made to suggest a curriculum framework so that appropriate and sustainable sports management training programmes can be offered. From a historical survey it became evident that sports management training programmes are in a relatively early development phase. An analysis of international programmes revealed that these programmes focus mainly on the economic and management activities in sports management organisations. Few instances were found where human movement studies constituted a prominent part of the contents of the programmes. However, the opposite was found to be true when South African programmes were reviewed. The majority of these programmes include components of human movement studies/sport science in their contents. Some of the programmes focus specifically on human movement studies/sport science and merely offer introductory modules on aspects of sports management. This study indicates the necessity for sports management training programmes in higher education to fit into specific structures in the South African education framework. New developments centred around the South African Qualifications Authority, the Higher Education Board and more specifically the National Qualifications Framework have been researched and applied to sports management training programmes. To place this study within the perspective of curriculum development, various models and methods of curriculum evaluation were explored. As a result of this a synoptic list was compiled to which sports management programmes may be required to comply. As part of the study a questionnaire review was conducted to indicate sports managers' knowledge and skills requirements in three levels of management. Guidelines were derived from this for generic contents of sports management programmes. It was also indicated that specialist functions exist within the sports management industry and that this phenomenon cannot merely be ignored by academic institutions when curricula are designed. These findings were used to suggest a possible framework for sports management curricula. In the light of a changing environment in South Africa and the development of the professional sports management industry, it is necessary that this framework should continuously be supplemented in a dynamic sporting environment.AFRIKAANSE OPSOMMING: Die sportbedryf het in Suid-Afrika drasties begin verander toe beroepsport na jare van sportisolasie toenemend 'n werklikheid geword het. Uit hierdie veranderinge het daar nuwe beroepsmoontlikhede ontstaan deurdat professionele persone nodig was om professionele sport te bestuur. Hierdie nuwe professionele sportorganisasies is op die lees van ekonomies-aktiewe besighede geskoei wat beteken dat bestuurders op aile vlakke benodig is. Opleidingsinstellings het spoedig begin om programme aan te bied vir die opleiding van hierdie sogenaamde sportbestuurders. Alhoewel daar 'n verskeidenheid spesialiste in die sportomgewing werk, word die generiese term "sportbestuurder" gebruik om hierdie persone te identifiseer. Die toepaslike en volhoubare opleiding van sportbestuurders vorm die kern van ondersoek in hierdie studie. Opleidingsprogramme vir sportbestuuropleiding word meestal in departemente van menslike bewegingskunde of sportwetenskap aangebied, wat die vermoede laat ontstaan het dat hierdie programme slegs aangepaste menslike bewegingskundeprogramme is en nie noodwendig vir die volle spektrum van behoeftes van die professionele sportbestuurbedryf voorsiening maak nie. Die hoofdoel van hierdie studie was die daarstelling van 'n kurrikulumraamwerk vir sportbestuuropleiding wat nie net praktykgerig is nie, maar ook die volhoubaarheid van hierdie programme verseker. Om dit te verwesenlik, is daar gepoog om 'n internasionale en nasionale historiese perspektief oor sportbestuuropleiding daar te stel. 'n Teoretiese kurrikulummodel is beskryf met spesifieke verwysing na huidige onderwystendense in Suid-Afrika. Vervolgens is gepoog om vanuit die sportbedryf te bepaal wat die kennis- en vaardigheidsvereistes is wat die sportbestuurberoep aan individue stel. Uit hierdie gegewens is gepoog om 'n kurrikulumraamwerk te ontwerp ten einde 'n bydrae te maak tot die volhoubare en toepaslike voorsiening van sportbestuuropleiding. Uit 'n historiese oorsig het dit geblyk dat sportbestuuropleidingsprogramme in 'n relatief vroeë ontwikkelingsfase verkeer. Wat uit die ontleding van internasionale programme duidelik geblyk het, is dat hierdie programme veral op die ekonomiese en bestuursaktiwiteite van sportbestuurorganisasies gefokus is. Min gevalle is aangetref waar menslike bewegingskunde 'n prominente deel van die programinhoud uitmaak. Daar is egter bevind dat die teendeel grootliks waar is van programme in Suid-Afrika. Die meerderheid van die programme het wel komponente van menslike bewegingskunde/sportwetenskap as deel van die inhoud. Sommige programme fokus spesifiek op menslike bewegingskunde/sportwetenskap en bied sportbestuuraspekte slegs as inleidende modules aan. Die studie toon aan dat dit noodsaaklik is om sportbestuuropleidingsprogramme in hoër onderwys binne spesifieke strukture in die Suid-Afrikaanse opvoedingsraamwerk in te pas. Ontwikkelinge rondom die Suid-Afrikaanse Kwalifikasie-owerheid, die Hoër Onderwysraad en meer spesifiek die Nasionale Kwalifikasieraamwerk is ondersoek in die lig van moontlike toepassings op sportbestuurprogramme. Om die studie binne die perspektief van kurrikulumontwikkeling te plaas, is ondersoek ingestel na verskillende modelle en metodes van kurrikulumevaluering. Hieruit is 'n oorsiglys waaraan sportbestuurprogramme moontlik beoordeel kan word, saamgestel. 'n Vraelysondersoek is benut ten einde kennis- en vaardigheidsvereistes van sportbestuurders op drie bestuursvlakke aan te toon. Riglyne ten opsigte van generiese inhoude vir sportbestuurprogramme is hieruit verkry. Daar is ook aangetoon dat spesialisfunksies binne die sportbestuurbedryf bestaan en dat hierdie verskynsel tydens kurrikulumontwerp nie sonder meer deur akademiese instellings geignoreer kan word nie. Hierdie bevindinge is gebruik om 'n moontlike raamwerk vir sportbestuurkurrikula voor te stel. In die lig van 'n veranderende samelewing in Suid-Afrika en die ontwikkeling van die professionele sportbestuurbedryf is dit noodsaaklik dat hierdie raamwerk in 'n dinamiese sportomgewing voortdurend aangevul word