An unusual new fossil shark (Pisces: Chondrichthyes) from the Late Devonian of South Africa
- Authors: Anderson, M Eric , Long, John A , Gess, Robert W , Hiller, Norton
- Date: 1999
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/73910 , vital:30240 , http://museum.wa.gov.au/sites/default/files/10. Anderson, Long, Gess, Hiller.pdf
- Description: A new stem-group chondrichthyan fish, PlesioselacJllIs macracanthlls gen. et sp. nov., is described from the Late Devonian Witpoort Formation, representing an estuarine lagoon site, near Grahamstown, South Africa. Based on a single, fairly complete specimen, it is distinctive in its a single dorsal fin braced by a large, stout spine with numerous ribs and posterior denticles, apparently no second dorsal or anal fin, an amphistylic jaw suspension, and a distinctive triangular palatoquadrate. It is suggested that the species may represent a high-latitude, Late Devonian relict taxon.
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Anting in Afrotropical birds: a review
- Authors: Craig, Adrian J F K
- Date: 1999
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/447746 , vital:74671 , https://doi.org/10.1080/00306525.1999.9634237
- Description: Passive anting has been recorded from four non-passerine species in Africa, the Rock Kestrel Falco tinnunculus, the African Finfoot Podica senegalensis, the African Hoopoe Upupa epops and the Whitebacked Mousebird Colius colius. Active or passive anting has been recorded from 21 passerine species in 10 families in the wild, and in captive birds in a further 27 species of 3 families. Although such behaviour may have been overlooked or misinterpreted, the rarity of observations implies that in most species anting is likely to be infrequent. In all cases in which the ants have been identified, they were members of the sub-family Formicinae. It appears unlikely that any single functional explanation can account for the observed occurrences of this behaviour.
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Creating a Web-based Spatiotemporal GIS using Java and VRML
- Authors: Clayton, Peter G , Wells, George C , Preston, Michael
- Date: 1999
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/433413 , vital:72968 , https://www.learntechlib.org/p/7417/
- Description: This paper presents our approach towards creating a Web-based Spatiotemporal Geographic Information System, in particular, the creation of the spatial data set and the component interaction. It explores the possibility of rendering Virtual GIS Worlds in near real time across the WWW using a standard Web browser as the user interface. A" proof of concept" Web-based VGIS application was developed to investigate methods for the efficient transfer of high-bandwidth multimedia GIS content over the WWW, as well as providing a suitable development environment for research into Web-based Temporal GIS. This paper describes how VRML and Java were used to provide the visualisation of virtual worlds, interaction with individual objects inside the virtual world, and the query tools for adding, deleting, selecting or manipulating these objects or their associated attribute data.
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Graphicacy as a form of communication
- Authors: Wilmot, P Dianne
- Date: 1999
- Language: English
- Type: Article
- Identifier: vital:6091 , http://hdl.handle.net/10962/d1008613
- Description: Children of today inhabit a multi-dimensional world and in order to communicate effectively in it they need the ability to utilise four forms of communication namely, oracy, literacy, numeracy and graphicacy. Communicating in graphic form requires an ability to both encode and decode spatial information using symbols which requires the utilisation and application of spatial perceptual skills and concepts. The draft Curriculum Framework for General and Further Education and Training identifies graphic literacy as one of the critical outcomes of the new South African curriculum. Spatial information about the environment is most frequently communicated in the graphic mode. Yet if graphicacy is to be recognised as an essential mode of communication and, as such, a vital element in education, then we need to seek ways of developing and introducing an explicit and critical pedagogy in our schools to foster the development of graphic and critical graphic literacy. But first, the skills and concepts integral to graphicacy need to be identified and understood. This article provides a framework for thinking about graphicacy as a form of communication in the General Education and Training (GET) band, the compulsory component of South African education (Grades 1-9).
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Guy Butler (obituary)
- Authors: Wright, Laurence
- Date: 1999
- Language: English
- Type: Article
- Identifier: vital:7052 , http://hdl.handle.net/10962/d1007411
- Description: An obituary focusing on Guy Butler's Shakespearean preoccupations. The 1999/2000 volume of Shakespeare in Southern Africa only appeared in 2001. The Butler obituary was included as a 'stop-press' item as the volume went to print, which accounts for the apparent anomaly between the date of publication and the date of Guy Butler's death.
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Honeybees, Apis mellifera Linnaeus (Hymenoptera: Apidae), of equatorial Africa
- Authors: Radloff, Sarah E , Hepburn, H Randall
- Date: 1999
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/451885 , vital:75083 , https://hdl.handle.net/10520/AJA10213589_364
- Description: Morphometric and flight dimensional characters of worker honeybees, Apis mellifera Linnaeus, from equatorial Gabon were analysed by multivariate methods to characterize the population. A single morphocluster and a single flight dimension cluster were obtained. When these bees were grouped together with those of other countries of the region, again a single morphoduster and flight cluster were obtained. All of the outlier samples were previously designated as Apis mellifera adansonii Latreille and completely surround the Gabon samples, establishing the same subspecies membership for the latter. The bees of Gabon are morphometrically more homogeneous than in any other area of Africa.
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Lack of a response of the sub-tropical rodent (Saccostomus campestris) to a secondary plant compound, 6-methoxybenzoxazolinone—consequences for reproductive strategy
- Authors: White, Rehema M , Bernard, Ric T F
- Date: 1999
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/447273 , vital:74601 , https://www.ajol.info/index.php/az/article/view/154795
- Description: A potential strategy for southern African small mammals to maximise reproductive success is to cue breeding activity to rainfall and subsequent vegetative growth via a secondary plant compound such as 6-methoxybenzoxazolinone (6MBOA). This study investigated whether the sub-tropical rodent Saccostomus campestris utilised this compound to enhance reproductive activity. 6MBOA or control vehicle were injected into adult females and into peri-pubertal females under long day (LD) and short day (SD) photoperiods (adults n= 6 to 8: peri-pubertals n= 5 to 10/treatment). There was no significant effect of 6MBOA or photoperiod on uterine or ovarian masses nor on ovarian development in sacrificed animals, nor on age at vaginal opening of peri-pubertals It was concluded that 6MBOA is not a major stimulant of reproduction in this species. Rather, we propose that seasonal breeding occurs in response to multiple environmental cues. This reproductive strategy and omnivory permit.
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The Virtual Remote Control-An Extensible, Virtual Reality, User Interface Device
- Authors: Rorke, Michael , Bangay, Shaun D
- Date: 1999
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/432743 , vital:72896 , https://www.cs.ru.ac.za/research/Groups/vrsig/pastprojects/013interaction/paper02.pdf
- Description: Immersive virtual reality (VR) places the user inside of the computing envi-ronment, blurring the distinction between the environment itself and the user interface to access that environment non-obvious. This lack of distinction between environment and interface makes it difficult to place menus and other interface elements where the user is both able to access them easily and where they do not obscure large parts of the users field of view. We propose a system called the 'Virtual Remote Control' (VRC). The VRC con-sists of a physical device (a small touchpad tracked using a Polhemus In-sideTrak magnetic tracker) which the user is able to hold and for which there is a representation in the virtual environment. The VRC is represented in the environment by a virtual menu. The user is able to make selections from the virtual menu by moving their finger around the touch pad part of the VRC and 'tapping' on the required action. Additionally, the user is able to select an object for the action to be applied on, by 'pointing' the representa-tion of the VRC at the object-as one would point a remote control at a Hi-fi of TV set.
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Thermoregulatory capabilities of the woodland dormouse, Graphiurus murinus
- Authors: Whittington-Jones, Craig A , Brown, C R
- Date: 1999
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/447349 , vital:74613 , https://doi.org/10.1080/02541858.1999.11448485
- Description: The woodland dormouse, Graphiurus murinus, in common with many other small rodents, enters torpor under conditions of food deprivation and low temperatures. Its thermoregulatory capabilities under more favourable conditions, however, have not been investigated. We measured metabolism and thermoregulation in woodland dormice acclimated to long-day length, moderate temperature and abundant food over a temperature range (Ta) of approximately 5–37°C. The thermal neutral zone for this species lay between 29 and 35°C. Estimated resting metabolic rate (RMR) within this range averaged 21.10 ± 3.28 J g-1 h-1.
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