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22 results on '"J. A. Malan"'

1. The 1.28 GHz MeerKAT Galactic Center Mosaic

Author

I. Heywood, I. Rammala, F. Camilo, W. D. Cotton, F. Yusef-Zadeh, T. D. Abbott, R. M. Adam, G. Adams, M. A. Aldera, K. M. B. Asad, E. F. Bauermeister, T. G. H. Bennett, H. L. Bester, W. A. Bode, D. H. Botha, A. G. Botha, L. R. S. Brederode, S. Buchner, J. P. Burger, T. Cheetham, D. I. L. de Villiers, M. A. Dikgale-Mahlakoana, L. J. du Toit, S. W. P. Esterhuyse, B. L. Fanaroff, S. February, D. J. Fourie, B. S. Frank, R. R. G. Gamatham, M. Geyer, S. Goedhart, M. Gouws, S. C. Gumede, M. J. Hlakola, A. Hokwana, S. W. Hoosen, J. M. G. Horrell, B. Hugo, A. I. Isaacson, G. I. G. Józsa, J. L. Jonas, A. F. Joubert, R. P. M. Julie, F. B. Kapp, J. S. Kenyon, P. P. A. Kotzé, N. Kriek, H. Kriel, V. K. Krishnan, R. Lehmensiek, D. Liebenberg, R. T. Lord, B. M. Lunsky, K. Madisa, L. G. Magnus, O. Mahgoub, A. Makhaba, S. Makhathini, J. A. Malan, J. R. Manley, S. J. Marais, A. Martens, T. Mauch, B. C. Merry, R. P. Millenaar, N. Mnyandu, O. J. Mokone, T. E. Monama, M. C. Mphego, W. S. New, B. Ngcebetsha, K. J. Ngoasheng, M. T. Ockards, N. Oozeer, A. J. Otto, S. S. Passmoor, A. A. Patel, A. Peens-Hough, S. J. Perkins, A. J. T. Ramaila, N. M. R. Ramanujam, Z. R. Ramudzuli, S. M. Ratcliffe, A. Robyntjies, S. Salie, N. Sambu, C. T. G. Schollar, L. C. Schwardt, R. L. Schwartz, M. Serylak, R. Siebrits, S. K. Sirothia, M. Slabber, O. M. Smirnov, L. Sofeya, B. Taljaard, C. Tasse, A. J. Tiplady, O. Toruvanda, S. N. Twum, T. J. van Balla, A. van der Byl, C. van der Merwe, V. Van Tonder, R. Van Wyk, A. J. Venter, M. Venter, B. H. Wallace, M. G. Welz, L. P. Williams, and B. Xaia

Subjects
Space and Planetary Science, Astrophysics::High Energy Astrophysical Phenomena, Astrophysics of Galaxies (astro-ph.GA), FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics - Astrophysics of Galaxies, Astrophysics::Galaxy Astrophysics
Abstract

The inner $\sim$200 pc region of the Galaxy contains a 4 million M$_{\odot}$ supermassive black hole (SMBH), significant quantities of molecular gas, and star formation and cosmic ray energy densities that are roughly two orders of magnitude higher than the corresponding levels in the Galactic disk. At a distance of only 8.2 kpc, the region presents astronomers with a unique opportunity to study a diverse range of energetic astrophysical phenomena, from stellar objects in extreme environments, to the SMBH and star-formation driven feedback processes that are known to influence the evolution of galaxies as a whole. We present a new survey of the Galactic center conducted with the South African MeerKAT radio telescope. Radio imaging offers a view that is unaffected by the large quantities of dust that obscure the region at other wavelengths, and a scene of striking complexity is revealed. We produce total intensity and spectral index mosaics of the region from 20 pointings (144 hours on-target in total), covering 6.5 square degrees with an angular resolution of 4$"$,at a central frequency of 1.28 GHz. Many new features are revealed for the first time due to a combination of MeerKAT's high sensitivity, exceptional $u,v$-plane coverage, and geographical vantage point. We highlight some initial survey results, including new supernova remnant candidates, many new non-thermal filament complexes, and enhanced views of the Radio Arc Bubble, Sgr A and Sgr B regions. This project is a SARAO public legacy survey, and the image products are made available with this article., Comment: 29 pages, 15 figures, 3 tables, accepted for publication in the The Astrophysical Journal. Replacement arXiv version with higher quality figures

Published
2022
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2. A PANORAMA OF BIBLICAL STUDIES

Author

J C Malan

Subjects
Formative assessment, Value (ethics), Syllabus, Biblical studies, Panorama, Interpretation (philosophy), Perspective (graphical), Pedagogy, Relevance (law), Sociology
Abstract

This paper is meant to convey a general idea of the current functioning of Biblical Studies in Southern Africa. By means of approximate figures, a quantitative survey is given of students and teaching staff involved in Biblical Studies and Bible Education at schools, colleges and universities. The inference is drawn that at tertiary level we should be less concerned about an apparent overproduction of teachers for these subjects, but rather focus our attention on the significance and relevance of Biblical Studies in present-day South Africa. The second and main part of the paper is a qualitative survey in which an assessment of university, college and school syllabuses is given. The core syllabus for Biblical Studies at university level, as accepted by the Biblical Studies Society for Southern Africa, is taken as the frame of reference. The paper indicates how university syllabuses correlate with the core syllabus, but also how perspectives such as hermeneutical, historical, systematic and ethical are specially emphasized. Syllabus quotations on the ethical perspective provide a list of very relevant issues. And noteworthy answers to the questionnaire question on life-relatedness are added. School syllabuses are tactfully but critically discussed. In the Biblical Studies syllabus very little attention is given to the prophets and the letters, to the interpretation of Scripture, and to topical issues. Some of the Bible Education syllabuses do include – although inconspicuously placed – a few topical issues. The disappointing conclusion is that the life-relatedness of the Christian message is not taken seriously, except in some tertiary syllabuses. What is encouraging, however, are the questionnaire responses emphasizing our responsibility in respect of – The understanding of the Bible; The implications for daily living, Relationships with God and fellow-men, And the current situation South Africa; The formative value of Biblical Studies.

Published
2020
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3. The MeerKAT Galaxy Cluster Legacy Survey

Author

K. Knowles, W. D. Cotton, L. Rudnick, F. Camilo, S. Goedhart, R. Deane, M. Ramatsoku, M. F. Bietenholz, M. Brüggen, C. Button, H. Chen, J. O. Chibueze, T. E. Clarke, F. de Gasperin, R. Ianjamasimanana, G. I. G. Józsa, M. Hilton, K. C. Kesebonye, K. Kolokythas, R. C. Kraan-Korteweg, G. Lawrie, M. Lochner, S. I. Loubser, P. Marchegiani, N. Mhlahlo, K. Moodley, E. Murphy, B. Namumba, N. Oozeer, V. Parekh, D. S. Pillay, S. S. Passmoor, A. J. T. Ramaila, S. Ranchod, E. Retana-Montenegro, L. Sebokolodi, S. P. Sikhosana, O. Smirnov, K. Thorat, T. Venturi, T. D. Abbott, R. M. Adam, G. Adams, M. A. Aldera, E. F. Bauermeister, T. G. H. Bennett, W. A. Bode, D. H. Botha, A. G. Botha, L. R. S. Brederode, S. Buchner, J. P. Burger, T. Cheetham, D. I. L. de Villiers, M. A. Dikgale-Mahlakoana, L. J. du Toit, S. W. P. Esterhuyse, G. Fadana, B. L. Fanaroff, S. Fataar, A. R. Foley, D. J. Fourie, B. S. Frank, R. R. G. Gamatham, T. G. Gatsi, M. Geyer, M. Gouws, S. C. Gumede, I. Heywood, M. J. Hlakola, A. Hokwana, S. W. Hoosen, D. M. Horn, J. M. G. Horrell, B. V. Hugo, A. R. Isaacson, J. L. Jonas, J. D. B. Jordaan, A. F. Joubert, R. P. M. Julie, F. B. Kapp, V. A. Kasper, J. S. Kenyon, P. P. A. Kotzé, A. G. Kotze, N. Kriek, H. Kriel, V. K. Krishnan, T. W. Kusel, L. S. Legodi, R. Lehmensiek, D. Liebenberg, R. T. Lord, B. M. Lunsky, K. Madisa, L. G. Magnus, J. P. L. Main, A. Makhaba, S. Makhathini, J. A. Malan, J. R. Manley, S. J. Marais, M. D. J. Maree, A. Martens, T. Mauch, K. McAlpine, B. C. Merry, R. P. Millenaar, O. J. Mokone, T. E. Monama, M. C. Mphego, W. S. New, B. Ngcebetsha, K. J. Ngoasheng, M. T. Ockards, A. J. Otto, A. A. Patel, A. Peens-Hough, S. J. Perkins, N. M. Ramanujam, Z. R. Ramudzuli, S. M. Ratcliffe, R. Renil, A. Robyntjies, A. N. Rust, S. Salie, N. Sambu, C. T. G. Schollar, L. C. Schwardt, R. L. Schwartz, M. Serylak, R. Siebrits, S. K. Sirothia, M. Slabber, L. Sofeya, B. Taljaard, C. Tasse, A. J. Tiplady, O. Toruvanda, S. N. Twum, T. J. van Balla, A. van der Byl, C. van der Merwe, C. L. van Dyk, V. Van Tonder, R. Van Wyk, A. J. Venter, M. Venter, M. G. Welz, L. P. Williams, and B. Xaia

Subjects
Physics, Cosmology and Nongalactic Astrophysics (astro-ph.CO), Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Astrophysics - Astrophysics of Galaxies, Galaxy cluster, Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract

MeerKAT's large number of antennas, spanning 8 km with a densely packed 1 km core, create a powerful instrument for wide-area surveys, with high sensitivity over a wide range of angular scales. The MeerKAT Galaxy Cluster Legacy Survey (MGCLS) is a programme of long-track MeerKAT L-band (900-1670 MHz) observations of 115 galaxy clusters, observed for $\sim$6-10 hours each in full polarisation. The first legacy product data release (DR1), made available with this paper, includes the MeerKAT visibilities, basic image cubes at $\sim$8" resolution, and enhanced spectral and polarisation image cubes at $\sim$8" and 15" resolutions. Typical sensitivities for the full-resolution MGCLS image products are $\sim$3-5 {\mu}Jy/beam. The basic cubes are full-field and span 4 deg^2. The enhanced products consist of the inner 1.44 deg^2 field of view, corrected for the primary beam. The survey is fully sensitive to structures up to $\sim$10' scales and the wide bandwidth allows spectral and Faraday rotation mapping. HI mapping at 209 kHz resolution can be done at $0, Comment: 43 pages, 33 figures, 6 tables. Accepted for publication in Astronomy and Astrophysics

Published
2022
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4. THE CHALLENGE TO ORIGINALITY - AS ENCOUNTERED IN THE METHODOLOGY APPROACH OF CHRISTIAN RELIGIOUS EDUCATION COURSES DEVELOPED IN AFRICA

Author

J C Malan

Subjects
Christian Church, Aesthetics, Life style, Originality, media_common.quotation_subject, Indoctrination, Religious education, Sociology, DUAL (cognitive architecture), Content (Freudian dream analysis), Critical research, media_common
Abstract

After Jesus had brought a surprisingly original message, and had stressed the importance of understanding his invitation to a changed life style, the Christian church too often reverted to traditional content teaching and indoctrination. Honest, critical research was rejected and educational developments were ignored. Against such a background the recovering of Christian originality in the Christian Religious Education courses developed in Eastern Africa is to be welcomed. In these courses a life-related method is duly justified and effectively used. Jesus’ message and method were indeed original, in the dual sense of being first and being fresh. This challenge to implementation life-related originality instead of abstract traditionality should definitely be taken seriously in Christian Religious Education. But a similar life-approach should also be propagated in all education.

Published
2019
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5. Inflation of 430-parsec bipolar radio bubbles in the Galactic Centre by an energetic event

Author

Jasper Horrell, M. Serylak, T. D. Abbott, P. P. A. Kotzé, J. P. Burger, L. G. Magnus, A. A. Pate, P. S. Swart, A. Loots, S. Tshongweni, A. van der Byl, S. Buchner, Farhad Yusef-Zadeh, Jason Manley, T. W. Kusel, R. Renil, T. J. van Balla, D. H. Botha, A. R. Foley, N. Mnyandu, O. Mahgoub, A. G. Botha, B. M. Lunsky, L. C. Schwardt, Bruce Merry, A. J. Tiplad, C. J. Hoek, R. Siebrits, Dirk I. L. de Villiers, C. L. van Dyk, T. Cheetham, J. A. Malan, C.G. Van der Merwe, D. M. Horn, S. Salie, T. E. Monama, A. R. Isaacson, I. P. T. Moeng, Kshitij Thorat, E. F. Bauermeister, Roy Booth, F. Kapp, B. L. Fanaroff, Simon Perkins, M. C. Mphego, A. Rust, V. Van Tonder, W. S. New, Oleg Smirnov, S. Gounden, H. Kriel, J. D. B. L. Jordaan, M. A. Dikgale-Mahlakoana, R. T. Lord, L. J. du Toit, B. Ngcebetsha, S. W. P. Esterhuyse, P. Macfarlane, Sharmila Goedhart, D. T. Taylor, Justin L. Jonas, R. van Rooyen, C. Magozore, M. J. Hlakola, Dehann Fourie, Robert Lehmensiek, A. F. Joubert, Fernando Camilo, B. H. Wallace, D. Liebenberg, R. van Wyk, R. R. G. Gamatham, Gyula I. G. Józsa, Nadeem Oozeer, J. S. Kenyon, R. D. Malgas, Robert P. Millenaar, Matthys Maree, A. Hokwana, J. M. Chalmers, C. Tasse, L. P. Williams, R. M. Adam, Z. B. Brits, L. R. S. Brederode, W. D. Cotton, J. P. L. Main, M. G. Welz, B. Hugo, A. Peens-Hough, L. Sofeya, Ian Heywood, S. Ratcliffe, I. P. Theron, S. S. Passmoor, M. A. Aldera, A. J. Otto, S. K. Sirothia, R. P. M. Julie, Galaxies, Etoiles, Physique, Instrumentation (GEPI), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Active galactic nucleus, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Cosmic ray, Context (language use), Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Relativistic particle, 0103 physical sciences, Disc, 010306 general physics, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, ComputingMilieux_MISCELLANEOUS, Physics, [PHYS]Physics [physics], Supermassive black hole, Multidisciplinary, Star formation, Galactic plane, Astrophysics - Astrophysics of Galaxies, 13. Climate action, Astronomy and astrophysics, Astrophysics of Galaxies (astro-ph.GA), [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

The Galactic Centre contains a supermassive black hole with a mass of 4 million suns within an environment that differs markedly from that of the Galactic disk. While the black hole is essentially quiescent in the broader context of active galactic nuclei, X-ray observations have provided evidence for energetic outbursts from its surroundings. Also, while the levels of star formation in the Galactic Centre have been approximately constant over the last few hundred Myr, there is evidence of elevated short-duration bursts, strongly influenced by interaction of the black hole with the enhanced gas density present within the ring-like Central Molecular Zone at Galactic longitude |l| < 0.7 degrees and latitude |b| < 0.2 degrees. The inner 200 pc region is characterized by large amounts of warm molecular gas, a high cosmic ray ionization rate, unusual gas chemistry, enhanced synchrotron emission, and a multitude of radio-emitting magnetised filaments, the origin of which has not been established. Here we report radio imaging that reveals bipolar bubbles spanning 1 degree x 3 degrees (140 parsecs x 430 parsecs), extending above and below the Galactic plane and apparently associated with the Galactic Centre. The structure is edge-brightened and bounded, with symmetry implying creation by an energetic event in the Galactic Centre. We estimate the age of the bubbles to be a few million years, with a total energy of 7 x 10^52 ergs. We postulate that the progenitor event was a major contributor to the increased cosmic-ray density in the Galactic Centre, and is in turn the principal source of the relativistic particles required to power the synchrotron emission of the radio filaments within and in the vicinity of the bubble cavities., 25 pages, 3 figures, 3 tables, authors' version of a Letter published in Nature on 11 September 2019

Published
2019
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6. The 1.28 GHz MeerKAT DEEP2 Image

Author

K. M. B. Asad, T. E. Monama, E. F. Bauermeister, Bruce Merry, O. Toruvanda, S. J. Marais, B. M. Lunsky, L. C. Schwardt, H. Bester, H. Kriel, M. Geyer, S. February, B. H. Wallace, M. Serylak, S. N. Twum, N. Kriek, B. Taljaard, M. A. Dikgale-Mahlakoana, W. S. New, K. Madisa, R. M. Adam, Oleg Smirnov, S. Fataar, R. Millenaar, Z. R. Ramudzuli, S. Gounden, I. P. Theron, K. J. Ngoasheng, Z. B. Brits, J. Horrell, G. Stone, D. H. Botha, T. W. Kusel, B. Xaia, M. J. Hlakola, B. S. Frank, S. W. P. Esterhuyse, Jason Manley, James J. Condon, A. Robyntjies, J. A. Malan, Gyula I. G. Józsa, A. A. Patel, R. R. G. Gamatham, Justin L. Jonas, S. C. Gumede, R. Siebrits, A. J. T. Ramaila, M. T. O. Ockards, Nadeem Oozeer, J. P. Burger, A. Loots, M. A. Aldera, L. G. Magnus, R. P. M. Julie, B. L. Fanaroff, G. Fadana, Robert Lehmensiek, A. J. Otto, A. van der Byl, T. Mauch, T. J. van Balla, S. K. Sirothia, L. Sofeya, P. P. A. Kotzé, N. Mnyandu, M. S. de Villiers, T. Cheetham, J. S. Kenyon, R. Renil, J. M. Chalmers, Ian Heywood, A. M. Matthews, L. Richter, F. Kapp, S. Salie, A. R. Isaacson, I. P. T. Moeng, A. Peens-Hough, R. T. Lord, Dirk I. L. de Villiers, W. D. Cotton, V. A. Kasper, J. P. L. Main, Sharmila Goedhart, B. Hugo, L. P. Williams, C. Tasse, L. R. S. Brederode, A. Martens, M. G. Welz, S. J. Buchner, T. D. Abbott, Simon Perkins, M. C. Mphego, C.G. Van der Merwe, V. Van Tonder, C. T. G. Schollar, L. J. du Toit, Fernando Camilo, O. J. Mokone, A. J. Tiplady, T. G. H. Bennett, and B. Ngcebetsha

Subjects
Physics, 010504 meteorology & atmospheric sciences, Star formation, Image (category theory), Center (category theory), FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, 01 natural sciences, Astrophysics - Astrophysics of Galaxies, Galaxy, Luminosity, law.invention, Radio telescope, Telescope, Space and Planetary Science, law, Astrophysics of Galaxies (astro-ph.GA), 0103 physical sciences, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Luminosity function (astronomy)
Abstract

We present the confusion-limited 1.28 GHz MeerKAT DEEP2 image covering one $\approx 68'$ FWHM primary beam area with $7.6''$ FWHM resolution and $0.55 \pm 0.01$ $\mu$Jy/beam rms noise. Its J2000 center position $\alpha=04^h 13^m 26.4^s$, $\delta=-80^\circ 00' 00''$ was selected to minimize artifacts caused by bright sources. We introduce the new 64-element MeerKAT array and describe commissioning observations to measure the primary beam attenuation pattern, estimate telescope pointing errors, and pinpoint $(u,v)$ coordinate errors caused by offsets in frequency or time. We constructed a 1.4 GHz differential source count by combining a power-law count fit to the DEEP2 confusion $P(D)$ distribution from $0.25$ to $10$ $\mu$Jy with counts of individual DEEP2 sources between $10$ $\mu$Jy and $2.5$ mJy. Most sources fainter than $S \sim 100$ $\mu$Jy are distant star-forming galaxies obeying the FIR/radio correlation, and sources stronger than $0.25$ $\mu$Jy account for $\sim93\%$ of the radio background produced by star-forming galaxies. For the first time, the DEEP2 source count has reached the depth needed to reveal the majority of the star formation history of the universe. A pure luminosity evolution of the 1.4 GHz local luminosity function consistent with the Madau & Dickinson (2014) model for the evolution of star-forming galaxies based on UV and infrared data underpredicts our 1.4 GHz source count in the range $-5 \lesssim \log[S(\mathrm{Jy})] \lesssim -4$., Comment: 20 pages, 18 figures. Accepted for publication in ApJ

Published
2019
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7. Revival of the Magnetar PSR J1622-4950:Observations with MeerKAT, Parkes, XMM-Newton, Swift, Chandra, and NuSTAR

Author

G C Du Toit, T. D. Abbott, A. J. T. Ramaila, P. S. Swart, P. Ntuli, G. de Bruin, Stephanie Smith, T. E. Monama, C. Stuart, Andrew Jameson, R. Spann, H. Kriel, N. Matthysen, J. Horrell, K. M. B. Asad, D. H. Botha, L. P. Williams, L. D. Mc Nally, R. T. Lord, A. Struthers, W. de Villiers, H. Niehaus, E. F. Bauermeister, John Sarkissian, B. Jordaan, R. Andreas, T. G. H. Bennett, J. P. Conradie, Riana Geschke, I. Wait, B. Ngcebetsha, A. van der Byl, Ben Stappers, A. Robyntjies, J. P. Jansen van Rensburg, N. Mabombo, D. H. Hoorn, A. Nzama, Bruce Merry, L. Sofeya, Sharmila Goedhart, L. R. S. Brederode, M. J. Hlakola, I. Rammala, O. Toruvanda, S. Rakoma, B. L. Fanaroff, A. Rust, A. Martens, M. G. Welz, Y. Padayachee, C. T. G. Schollar, S. J. Marais, B. Xaia, J. P. van Staden, F. Karels, T. Baloyi, B. de Swardt, I. Liebenberg, Vanessa A. Moss, A. L. Walker, C.G. Van der Merwe, W. S. New, E. C. Knox-Davies, R. Millenaar, P. Prozesky, L. J. du Toit, O. J. Mokone, K. Madisa, G. Sethosa, Griffin Foster, T. L. Grobler, Tom Alberts, S. S. Passmoor, F. Joubert, A. A. Patel, D. Koch, Ramesh Karuppusamy, L. Richter, Kshitij Thorat, O. Mahgoub, Jason Manley, C. Sharpe, M. J. Slabber, P. L. van der Merwe, S. Fataar, G. B. Taylor, M. Rasivhaga, P. Sunnylall, MacCalvin Kariseb, Gyula I. G. Józsa, A. R. Foley, N. Marais, M. A. Dikgale, J. P. Burger, C. Olyn, S. Paula, A. J. Otto, S. Ratcliffe, B. Pholoholo, R. Renil, T. Macdonald, Justin L. Jonas, R. van Rooyen, P. Scholz, Oleg Smirnov, B. H. Wallace, Fernando Camilo, A. Peens-Hough, S. Lamoor, F. Obies, L. Marais, T. J. Steyn, M. T. O. Ockards, O. Jacobs, C. Mjikelo, A. J. Tiplady, Roy Booth, D. Liebenberg, R. Strong, T. J. van Balla, P. C. van Niekerk, S. D. Matshawule, V. Van Tonder, C. de Waal, S. K. Sirothia, D. Rosekrans, R. M. Adam, L. Mafhungo, Matthew Bailes, G. Adams, P. P. A. Kotzé, D. M. Horn, S. Salie, M. S. de Villiers, Howard C. Reader, A. R. Isaacson, Dehann Fourie, B. Taljaard, C. de Villiers, A. F. Joubert, M. Serylak, T. Mauch, N. Sambu, Victoria M. Kaspi, C. C. Julius, N. Mnyandu, S. Seranyane, A. Krebs, Simon Johnston, N. Young, L. van den Heever, M. Manzini, R. van Wyk, M. Obrocka, N. Songqumase, T. W. Kusel, M. C. Mphego, J. A. Malan, I. P. T. Moeng, P. Malgas, K. J. Ngoasheng, B. M. Lunsky, L. C. Schwardt, M. Merryfield, W. van Straten, V. Thondikulam, B. Hugo, Nadeem Oozeer, Robert F. Archibald, P. Macfarlane, T. Cheetham, Aris Karastergiou, J. Conradie, D. Steyn, S. C. Gumede, S. Makhathini, S. W. P. Esterhuyse, N. Mkhabela, D. Booisen, R. P. M. Julie, Gianni Bernardi, L. Boyana, N. Kriek, Dirk I. L. de Villiers, T. Baxana, Cyril Tasse, M. Maree, Robert Lehmensiek, R. R. G. Gamatham, S. Zitha, D. E. Baker, K. Montshiwa, C. Magozore, Z. R. Ramudzuli, T. Gatsi, George Hobbs, S. J. Buchner, I. P. Theron, R. Siebrits, John Reynolds, A. Hokwana, F. Kapp, L. G. Magnus, V. A. Kasper, J. P. L. Main, J. van Aardt, David B. Davidson, ZAF, Unité Scientifique de la Station de Nançay (USN), Centre National de la Recherche Scientifique (CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers en région Centre (OSUC), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO), Galaxies, Etoiles, Physique, Instrumentation (GEPI), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Université d'Orléans (UO)-Observatoire des Sciences de l'Univers en région Centre (OSUC), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, PSL Research University (PSL)-Centre National de la Recherche Scientifique (CNRS), and PSL Research University (PSL)-PSL Research University (PSL)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Swift, individual (PSR J16224950) [pulsars], 010504 meteorology & atmospheric sciences, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Magnetosphere, Flux, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Ephemeris, Magnetar, 01 natural sciences, general [pulsars], stars: neutron, stars: magnetars, neutron [stars], Pulsar, pulsars: general, 0103 physical sciences, magnetars [stars], 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, computer.programming_language, High Energy Astrophysical Phenomena (astro-ph.HE), Physics, Quiescent state, Astronomy and Astrophysics, Neutron star, pulsars: individual, Space and Planetary Science, Astrophysics - High Energy Astrophysical Phenomena, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], computer
Abstract

New radio (MeerKAT and Parkes) and X-ray (XMM-Newton, Swift, Chandra, and NuSTAR) observations of PSR J1622-4950 indicate that the magnetar, in a quiescent state since at least early 2015, reactivated between 2017 March 19 and April 5. The radio flux density, while variable, is approximately 100x larger than during its dormant state. The X-ray flux one month after reactivation was at least 800x larger than during quiescence, and has been decaying exponentially on a 111+/-19 day timescale. This high-flux state, together with a radio-derived rotational ephemeris, enabled for the first time the detection of X-ray pulsations for this magnetar. At 5%, the 0.3-6 keV pulsed fraction is comparable to the smallest observed for magnetars. The overall pulsar geometry inferred from polarized radio emission appears to be broadly consistent with that determined 6-8 years earlier. However, rotating vector model fits suggest that we are now seeing radio emission from a different location in the magnetosphere than previously. This indicates a novel way in which radio emission from magnetars can differ from that of ordinary pulsars. The torque on the neutron star is varying rapidly and unsteadily, as is common for magnetars following outburst, having changed by a factor of 7 within six months of reactivation., Comment: Published in ApJ (2018 April 5); 13 pages, 4 figures

Published
2018
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8. Verification measurements of the Karoo Array timing system: a laser radar based time transfer system

Author

E. F. Bauermeister, H. Kriel, R. R. G. Gamatham, Tim Gibbon, G. Adams, F. Kapp, R. Siebrits, T. D. Abbott, J. A. Malan, and J. P. Burger

Subjects
Physics, Coordinated Universal Time, Real-time computing, Astrophysics::Instrumentation and Methods for Astrophysics, Atomic clock, law.invention, Radio telescope, Telescope, law, Frequency domain, Astronomical interferometer, Time transfer, Reflectometry, Remote sensing
Abstract

An optical fiber based laser radar time transfer system has been developed for the 64-dish MeerKAT radiointerferometer telescope project to provide accurate atomic time to the receivers of the telescope system. This time transfer system is called the Karoo Array Timing System (KATS). Calibration of the time transfer system is essential to ensure that time is accurately transferred to the digitisers that form part of the receivers. Frequency domain reflectometry via vector network analysers is also used to verify measurements taken using time interval counters. This paper details the progress that is made in the verification measurements of the system in order to ensure that time, accurate to within a few nanoseconds of the Universal Coordinated Time (UTC, is available at the point where radio signals from astronomical sources are received. This capability enables world class transient and timing studies with a compact radio interferometer, which has inherent advantages over large single dish radio-telescopes, in observing the transient sky.

Published
2017
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9. Interpretasie van die metafoor 'saam met Christus gekruisig' (Gal. 2:15-21)

Author

J. J. Janse van Rensburg and J. P. Malan

Subjects
Philosophy, Galatians 2:15-21, lcsh:Practical Theology, Metaphor, Crucified With Christ, Theology, lcsh:Practical religion. The Christian life, Crucifiction, lcsh:BV1-5099, lcsh:BV4485-5099
Abstract

Eerstens word bepaal wat ’n metafoor is en riglyne word neergelê vir die interpretasie van ’n metafoor. Dié riglyne word dan toegepas op die metafoor, saam met Christus gekruisig, in Galasiërs 2:15-21. Die grammaties-historiese eksegetiese metode word gevolg, soos voor- gestel deur De Klerk en Van Rensburg (2005).

Published
2008

10. Engineering and science highlights of the KAT-7 radio telescope

Author

W. New, D. Rosekrans, Nadeem Oozeer, F. Curtolo, M. Fijalkowski, S. Seranyane, A. Rust, J. R. Manley, I. P. Theron, N. Marais, A. C. Schröder, P. A. Woudt, R. T. Lord, Sharmila Goedhart, M. S. de Villiers, R. P. M. Julie, B. L. Fanaroff, Rob Fender, G. Coreejes, L. Sofeya, Claude Carignan, D. S. Shepherd, R. Lehmensiek, L. P. Williams, S. J. Marais, O. J. Mokone, Jonathan T. L. Zwart, R. Springbok, P. Gibbs, I. Liebenberg, P. Prozesky, Vanessa A. Moss, J. Horrell, Justin L. Jonas, R. van Rooyen, D. H. Botha, Roy Booth, A. Martens, L. G. Magnus, M. G. Welz, L. Richter, J. A. Malan, Tom Alberts, A. J. Tiplady, S. Mthembu, M. Madlavana, P. P. A. Kotzé, J. Grobbelaar, L. van den Heever, A. Langman, Venkatasubramani L. Thondikulam, S. Rajan, K. Cloete, S. Tshongweni, A. Peens-Hough, P. C. van Niekerk, N. J. Young, P. Herselman, S. J. Buchner, A. L. Walker, P. Macfarlane, F. Kapp, R. P. Armstrong, R. Spann, A. Dikgale, Kelley M. Hess, L. J. du Toit, M. Wolleben, M. Maree, J. Ludick, S. S. Passmoor, R. Siebrits, S. Blose, T. Cheetham, D. George, R. Renil, G. D. Nicholson, L. C. Schwardt, B. S. Frank, P. S. Swart, A. Loots, S. W. P. Esterhuyse, S. Wakhaba, C. J. T. van der Merwe, C. Magozore, T. W. Kusel, S. Ratcliffe, R. C. Crida, S. C. Gumede, M. Serylak, A. R. Foley, H. Bester, J. D. B. L. Jordaan, L. Marais, D. M. Lucero, S. D. Cross, D. Liebenberg, A. Barta, A. B. Pińska, E. F. Bauermeister, Dehann Fourie, O. Toruvanda, N. Hoek, Research School of Earth Sciences, Australian National University ( ANU ), Estrato Research and Development Ltd, Interdisciplinary Centre for Security, Reliability and Trust [Luxembourg] ( SnT ), Université du Luxembourg ( Uni.lu ), Faculty of Science, Technology and Communication [Luxembourg] ( FSTC ), University of Luxembourg [Luxembourg], Département de Physique [Montréal], Université de Montréal, Department of Paediatric Endocrinology, Royal Victoria Infirmary, Institute of Human Genetics, Centre for Life, Newcastle University [Newcastle], Développement et Communication Chimique chez les Insectes ( DCCI ), Centre National de la Recherche Scientifique ( CNRS ) -Université de Bourgogne ( UB ) -AgroSup Dijon - Institut National Supérieur des Sciences Agronomiques, de l'Alimentation et de l'Environnement, Animal Demography Unit, University of Cape Town, University of Southampton (Southampton, UK), Institute of Physics, University of Silesia, Rapita Systems Ltd [York], Department of Medical Oncology, Royal Melbourne Hospital, Brain and Mind Institute, Ecole Polytechnique Fédérale de Lausanne ( EPFL ), Service d'Explorations fonctionnelles multidisciplinaires [CHU Tenon], CHU Tenon [APHP]-Assistance publique - Hôpitaux de Paris - AP-HP (FRANCE), Service d'urologie [Mondor], Assistance publique - Hôpitaux de Paris (AP-HP)-Hôpital Henri Mondor-Université Paris-Est Créteil Val-de-Marne - Paris 12 ( UPEC UP12 ), OMedical Oncology, Guy's and St Thomas' Hospital [London], Institute of Cardiovascular and Medical Sciences, Electrocardiology Section, University of Glasgow, Glasgow, United Kingdom, Department of Computer and Information Science [Trondheim], Norwegian University of Science and Technology [Trondheim] ( NTNU ), Bordeaux Imaging Center ( BIC ), Université de Bordeaux ( UB ) -Institut François Magendie-Institut National de la Santé et de la Recherche Médicale ( INSERM ) -Centre National de la Recherche Scientifique ( CNRS ), Laboratoire de l'Accélérateur Linéaire ( LAL ), Université Paris-Sud - Paris 11 ( UP11 ) -Institut National de Physique Nucléaire et de Physique des Particules du CNRS ( IN2P3 ) -Centre National de la Recherche Scientifique ( CNRS ), School of Mathematics [Birmingham], University of Birmingham [Birmingham], Institut für Spezielle Botanik und Funktionelle Biodiversität, University of Leipzig, German Aerospace Center ( DLR ), University of the Western Cape, Unité Scientifique de la Station de Nançay ( USN ), Institut national des sciences de l'Univers ( INSU - CNRS ) -Observatoire de Paris-Université d'Orléans ( UO ) -Centre National de la Recherche Scientifique ( CNRS ), Materials Laboratory Rand Afrikaans University, Rand Afrikaans University, Jodrell Bank Centre for Astrophysics, University of Manchester [Manchester], School of Physics & DST-NRF, University of the Witwatersrand, University of the Witwatersrand [Johannesburg] ( WITS ), University of Southampton, Unité Scientifique de la Station de Nançay (USN), Centre National de la Recherche Scientifique (CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers en région Centre (OSUC), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO), Jodrell Bank Centre for Astrophysics (JBCA), University of the Witwatersrand [Johannesburg] (WITS), and Astronomy

Subjects
Cryogenic system, radio continuum: general, FOS: Physical sciences, 01 natural sciences, law.invention, Radio telescope, Telescope, Pulsar, law, 0103 physical sciences, Very-long-baseline interferometry, Aerospace engineering, Open architecture, instrumentation: interferometers, 010303 astronomy & astrophysics, Instrumentation and Methods for Astrophysics (astro-ph.IM), [ SDU.ASTR ] Sciences of the Universe [physics]/Astrophysics [astro-ph], Physics, Protocol data unit, 010308 nuclear & particles physics, business.industry, Astronomy, Astronomy and Astrophysics, [SDU.ASTR.IM]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Instrumentation and Methods for Astrophysic [astro-ph.IM], Space and Planetary Science, business, Astrophysics - Instrumentation and Methods for Astrophysics, radio lines: general, [ SDU ] Sciences of the Universe [physics]
Abstract

The construction of the seven-dish Karoo Array Telescope (KAT-7) array in the Karoo region of the Northern Cape in South Africa was intended primarily as an engineering prototype for technologies and techniques applicable to the MeerKAT telescope. This paper looks at the main engineering and scientific highlights from this effort, and discusses their applicability to both MeerKAT and other next-generation radio telescopes. In particular, we found that the composite dish surface works well, but it becomes complicated to fabricate for a dish lacking circular symmetry; the Stirling cycle cryogenic system with ion pump to achieve vacuum works but demands much higher maintenance than an equivalent Gifford-McMahon cycle system; the ROACH (Reconfigurable Open Architecture Computing Hardware)-based correlator with SPEAD (Streaming Protocol for Exchanging Astronomical Data) protocol data transfer works very well and KATCP (Karoo Array Telescope Control Protocol) control protocol has proven very flexible and convenient. KAT-7 has also been used for scientific observations where it has a niche in mapping low surface-brightness continuum sources, some extended H I haloes and OH masers in star-forming regions. It can also be used to monitor continuum source variability, observe pulsars, and make Very Long Baseline Interferometry observations.

Published
2016
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12. A critical review of hypopharyngeal carcinomas--1975-1985

Author

J F, Malan, S L, Sellars, and D, Kranold

Subjects
Male, Hypopharyngeal Neoplasms, Treatment Outcome, Carcinoma, Squamous Cell, Humans, Female, Life Tables, Middle Aged, Combined Modality Therapy
Abstract

Seventy-seven patients with hypopharyngeal carcinomas who presented to Groote Schuur Hospital between 1975 and 1985 are reviewed. Of these patients 76.6%, mostly with pyriform fossa tumours, had advanced disease. The overall 5-year survival was poor (10.5%) despite combined radiotherapy and surgery in many. Local tumour control remains poor and a split course of radiotherapy offers no solution.

Published
1993

13. Ostrich (Struthio camelus) immobilisation using carfentanil and xylazine and reversal with yohimbine and naltrexone

Author

J P, Raath, S K, Quandt, and J H, Malan

Subjects
Birds, Fentanyl, Xylazine, Immobilization, Animals, Yohimbine, Naltrexone
Abstract

Ostriches (Struthio camelus) (n = 20) were immobilised from a helicopter by darting with a total dose of 3 mg carfentanil and 150 mg xylazine. An initial excitement phase was displayed, commencing on average at 2.67 min (S.D. 0.72) after darting, and the average time to recumbency was 4.97 min (S.D. 1.05). The average heart and respiration rates prior to reversal were 121.2 (S.D. 19.96) and 13.7 (S.D. 5.96) min-1 respectively. Reversal was achieved by the intravenous injection of yohimbine at approximately 0.125 mg kg-1 and 300 mg of naltrexone, and was uneventful. Further investigations need to be done to establish the most appropriate dosage rates for these preparations in ostriches.

Published
1992

14. Plants of the Olympic Coastal Forests: ancient knowledge of materials and medicines and future heritage

Author

D R, Forlines, T, Tavenner, J C, Malan, and J J, Karchesy

Subjects
Flavonoids, Washington, Plants, Medicinal, Phenols, Polymers, Indians, North American, Polyphenols, Phytotherapy
Abstract

The indigenous people of the west coast of Washington State's Olympic Peninsula have used a wide variety of forest plants for centuries to make materials and medicines. The late David Forlines shared at least eight generations of the knowledge of uses of these plants for materials and medicines with us in hopes that this information might be used 'to help science catch up with the old people.' Dyes, paints and adhesives were some of the materials made. The medicines were often administered as teas, but in some cases, fresh plant material was required. Some parallels were found to European and Chinese uses of similar species. Plants from the family Rosaceae had the greatest number of medicinal uses, but several other plant families known to contain polyphenols were also encountered. The role of polyphenols in the use of these plants is difficult to estimate because in many cases the plants have not been studied chemically. A preliminary screening indicated that many of the plants were rich in procyanidins and associated compounds.

Published
1992

15. Mastoid surgery at the Red Cross War Memorial Children's Hospital 1986-1988

Author

C. A. J. Prescott and J. F. Malan

Subjects
medicine.medical_specialty, Mastoiditis, Mastoides, Open cavity, Chronic Suppurative Otitis Media, Temporalis fascia, Otitis Media, Suppurative, Mastoid, Medicine, Humans, Mastoid surgery, Child, Cholesteatoma, Ear Diseases, biology, business.industry, Age Factors, Infant, General Medicine, medicine.disease, biology.organism_classification, Surgery, Otorhinolaryngology, El Niño, Child, Preschool, Acute Disease, Chronic Disease, business
Abstract

Eighty-three children between ages 0–12 years had mastoid surgery in the three year period 1986–88. The indications were acute mastoiditis (30 children), uncontrolled chronic suppurative otitis media (CSOM) (24 children), cholesteatoma (22 children) and a miscellaneous group (7 children). Forty-seven per cent of those with acute mastoiditis were under one year but the 27 per cent with cholesteatoma as the precipitating cause were 4–12 years. Twenty-three per cent had significant complications. Typmano-mastoid surgery was employed to resolve uncontrolled CSOM. Children were between 2–12 years and 62 per cent were below the 25th centile for weight. Seventy-nine per cent of the tympanic membrane grafts were successful. The children with cholesteatoma were between 3–12 years and 76 per cent were below the 25th centile for weight. Eight of them only presented after the onset of acute mastoiditis. One child had a definite congenital cholesteatoma. Only one had a pars flaccida origin of the cholesteatoma sac and only eight an origin from the postero-superior pars tensa. All had open cavity surgery. When the cavity was lined by temporalis fascia, healing was improved markedly.

Published
1991

16. Water management challenges at Mushandike irrigation scheme in Runde catchment, Zimbabwe

Author

J. A. Malanco, H. Makurira, E. Kaseke, and W. Gumindoga

Subjects
Environmental sciences, GE1-350, Geology, QE1-996.5
Abstract

Mushandike Irrigation Scheme, constructed in 1939, is located in Masvingo District and is one of the oldest irrigation schemes in Zimbabwe. Since 2002, the scheme has experienced severe water shortages resulting in poor crop yields. The low crop yields have led to loss of income to the smallholder farmers who constitute the irrigation scheme leading to water conflicts. The water stress at the scheme has been largely attributed to climate change and the uncontrolled expansion of the land under irrigation which is currently about 1000 ha against a design area of 613 ha. This study sought to determine the actual causes of water shortage at Mushandike Irrigation Scheme. Hydro-climatic data was analysed to establish if the Mushandike River system generates enough water to guarantee the calculated annual yield of the dam. Irrigation demands and efficiencies were compared against water availability and dam releases to establish if there is any deficit. The Spearman's Rank Correlation results of 0.196 for rainfall and 0.48 for evaporation confirmed positive but insignificant long-term changes in hydro-climatic conditions in the catchment. Water budgets established that the yield of the dam of 9.2 × 106 m3 year−1 is sufficient to support the expanded area of 1000 ha provided in-field water management efficiencies are adopted. The study concludes that water shortages currently experienced at the scheme are a result of inefficient water management (e.g. over-abstraction from the dam beyond the firm yield, adoption of inefficient irrigation methods and high channel losses in the canal system) and are not related to hydro-climatic conditions. The study also sees no value in considering inter-basin water transfer to cushion the losses being experienced at the scheme.

Published
2018
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20. Genetic incompatibility between Boophilus decoloratus (Koch, 1844) and Boophilus microplus (Canestrini, 1888) and hybrid sterility of Australian and South African Boophilus microplus (Acarina: Ixodidae)

Author

A M, Spickett and J R, Malan

Subjects
Male, Ticks, Infertility, Animals, Hybridization, Genetic, Female
Abstract

Virgin females of both Boophilus decoloratus and Boophilus microplus, when mated with males of the other species, subsequently produced sterile eggs. Counts of spermiophore capsules in female seminal receptacles showed that the males of both species will mate with the females of both species and that B. microplus males show a slightly greater, but statistically insignificant, mating capacity than B. decoloratus males. South African B. microplus females, when mated with an Australian strain of B. microplus males, produced a 62% yield of viable hybrid progeny while the reciprocal cross produced only a 1,82% hatch of non-viable larvae. The hybrids were sterile when interbred and no hatch resulted when the Fl males were backcrossed with parent females. The reciprocal backcross of hybrid Fl females to parent males resulted in a low percentage hatch of non-viable larvae.

Published
1978

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