Comparative developmental osteology of the seahorse skeleton reveals heterochrony amongst Hippocampus sp. and progressive caudal fin loss

Background: Seahorses are well known for their highly derived head shape, prehensile tail and armoured body. They belong to the family of teleosts known as Syngnathidae, which also includes the pipefishes, pipehorses and seadragons. Very few studies have investigated the development of the skeleton of seahorses because larvae are extremely difficult to obtain in the wild and breeding in captivity is rarely successful. Here we compare the developmental osteology of Hippocampus reidi over an ontogenetic series spanning the first 93 days after release from the brood pouch to that of a smaller series of Hippocampus; namely H. subelongatus. Results: We compare the osteology in these two species over growth to the published description of the dwarf species, H. zosterae. We show that ossification onset in H. subelongatus is earlier than in H. reidi, despite similar sizes at parturition. Interestingly, the timing of development of the bony skeleton in H. zosterae is similar to that of the larger species, H. subelongatus. Furthermore, we show that the growth rate of all three species is similar up until about 30 days post pouch release. From this stage onwards in the life history, the size of the dwarf species H. zosterae remains relatively constant whilst the other two species continue growing with an accelerated growth phase. Conclusion: This data together with a phylogenetic assessment suggests that there has been a heterochronic shift (a delay) in the timing of ossification in H. reidi and accelerated bonedevelopment in H. zosterae. That is, H. zosterae is not a developmentally truncated dwarf species but rather a smaller version of its larger ancestor, "a proportioned dwarf" species. Furthermore, we show that caudal fin loss is incomplete in Hippocampus seahorses. This study shows that these three species of Hippocampus seahorses have evolved (either directly or indirectly) different osteogenic strategies over the last 20-30 million years of seahorse evolution

Disturbance and habitat factors in a small reserve : home range establishment by black rhinocerous (diceros bicornis minor)

MSc., Faculty of Science, University of the Witwatersrand, 2011Black rhinos are being moved to small protected areas in an attempt to expand their range; and factors commonly found within these small protected areas could influence black rhino ecology. From the literature we understand how biological factors affect rhino resource selection but not in the context of small reserves. This study investigates the home range establishment of black rhinos and those factors commonly associated with small reserves that affect rhino habitat-use as well as weigh the relative importance of each of them. The factors considered were human disturbances such as residences, lodges, roads and fences, slope, elevation, perennial water, burnt areas and vegetation type. Minimum convex polygon, 50% core and 95% local convex hull (LoCoH) was used to generate home ranges from sightings data collected for 17 individuals. The mean 95% LoCoH home range was 3.77 km² (95% CI: 2.92- 4.63, n=17), and is comparatively small in relation to the adaptive kernel home ranges of previous studies. A use-availability resource selection function showed that black rhinos avoided areas close to residences, lodges, camps, and perennial water, and these variables played a bigger role than their selection for thicket vegetation. These factors have a highly significant effect on rhino resource selection, and this effect is magnified due to the density of human disturbances and water points commonly found in small reserves. It is essential that this knowledge be applied in the management of reserves protecting black rhinos

Should Afrikaans be restandardised

CITATION: Odendaal, G. 2014. Moet Afrikaans geherstandaardiseer word? Tydskrif vir Geesteswetenskappe, 54(4):656-674.The original publication is available at http://www.scielo.org.za/scielo.php?script=sci_issuetoc&pid=0041-475120140004&lng=en&nrm=isoAFRIKAANSE OPSOMMING: Dit word gedoen deur eerstens ’n oorsig te gee oor die redes waarom Standaardafrikaans veral sedert die 1980’s nie as verteenwoordigend van die totale Afrikaanse spraakgemeenskap beskou word nie. Drie redes word hiervoor aangevoer, waaronder die oormatige vernederlandsing van Afrikaans tydens standaardisering, die miskenning van die Engelse invloed op Afrikaans deur middel van anglisismejag, en die miskenning en uitsluiting van ander variëteite van Afrikaans gedurende die standaardiseringsprosesENGLISH ABSTRACT: Given the international tendency towards democracy, the relevance of standard languages, which are undeniably ideological and discriminatory in nature, is increasingly being questioned. In the Afrikaans speech community the legitimacy of Standard Afrikaans has been questioned since the 1980s due to its association with apartheid. In recent times this awareness of the politicisation of Standard Afrikaans has led some Afrikaans linguists to ask the question whether or not Afrikaans should be restandardised. In an attempt to provide an answer to this question, this paper investigates whether or not restandardisation is desirable from a sociolinguistic viewpoint. This is done by giving an overview of why Standard Afrikaans is not seen as being representative of the entire Afrikaans speech community since the 1980s, why it is necessary that the standard be redefined, and lastly, what the restandardisation of Afrikaans would entail in outline. There are various reasons why Afrikaans is not representative of the entire Afrikaans speech community, the first being that standardisers relied heavily on Dutch during the standardisation process. By introducing many Dutch loan words into Afrikaans and relying heavily on the Dutch morphosyntactic pattern, the natural development of Afrikaans was disturbed. This Dutchification of Standard Afrikaans gave the standard an artificial nature which made it difficult for speakers of Afrikaans to learn. As a result of anti-British sentiments after the South African War, the standardisation of Afrikaans was also characterised by opposition against Anglicisms in Afrikaans. An attempt was made to remove as many traces of English influence on Afrikaans as possible, thereby denying the real language contact situation. This anti-English attitude further alienated speakers from the standard and led to diglossia in the Afrikaans speech community. Lastly, the vernacular varieties of Afrikaans, especially those spoken by coloured speakers of Afrikaans, were disregarded during standardisation. Not only was Standard Afrikaans appropriated as a “white man’s” language, but it was also based on Eastern Cape Afrikaans, which was mainly spoken by white speakers of Afrikaans. The stigmatisation of the vernacular varieties of Afrikaans led to discrimination against the speakers of these varieties on a social, educational and economic level. Vernacular speakers were marginalised as they were often excluded from all language domains for higher functions and have difficulty acquiring the standard language. Seeing as standardisation inhibits variation and strives towards uniformity of linguistic form, one could argue that the standard language cannot be representative of the entire speech community. This view on the standard language as a seemingly innocent variety ignores the fact that standardisation is ideologically motivated, as it favours the elite in a given speech community. This elitist situation is, however, no longer tenable in a democratic society. At the same time, one cannot deny that standard languages play an important role in the political, economic and educational life of a speech community. As democratising language planning, restandardisation can play an important role in resolving this tension in the standard language. As deliberate language planning from above and from below, aimed at revising the form and function of a standard language and influencing the linguistic behaviour of a speech community in order to create a democratic standard, restandardisation is aimed at correcting some social injustice or another in the speech community by standardising the language from a broader varietal base, thereby making the standard language more inclusive and empowering all speakers. This implies that Standard Afrikaans should be redefined in order to include all varieties of Afrikaans, as well as lessening the influence of Dutch on Afrikaans and giving recognition to the influence of English on Afrikaans. Although the Dutch burden on Standard Afrikaans has been lifted to a certain extent over the past years, there are Dutchisms in Afrikaans which make the language unnecessarily formal and alienate speakers. The restandardisation of Afrikaans thus entails that Dutch should no longer be used as norm for Afrikaans. Over the years there has also been greater realism with regard to the influence of English on Afrikaans, but there are still many English loans missing in Standard Afrikaans which have been prevalent in the vernacular for many years. The restandardisation of Afrikaans should lead to a greater acceptance of English influence on Afrikaans, as English often has an enriching effect on Afrikaans. Disregard of this influence may alienate speakers to such an extent that they decide to use English because they have difficulty acquiring Standard Afrikaans. Lastly, there has also been an increased acceptance of other varieties of Afrikaans into the standard. However, much still needs to be done, since especially coloured speakers of Afrikaans feel like strangers in their own language. Standard Afrikaans should be broadened to include not only lexical items from the vernacular varieties of Afrikaans, but also give recognition to grammatical differences. Restandardisation would further require that norms be determined in a democratic manner, so that all speakers may have a say in the structure of the standard. In this way, restandardisation can be utilised to reform Standard Afrikaans in order to serve the entire speech community, thereby reflecting the democratic ideals of society.Publishers' Versio

Space matters: the relational power of mobile technologies

The ubiquitous presence of mobile telephony and proliferation of digital networks imply a critical role for these technologies in overcoming the constraints of space in fragmented cities. Academic literature draws from a range of disciplines but fails to address the significance of new technologies for African and South African cities. Debates on technologies and urban spaces reflect a Northern bias and case literature that dwells on the developmental aspects of ICT do not engage with the broader significance with regards to urban change in African cities. This research addresses these gaps by examining the local transformative qualities of mobile telephony in a South African city, Durban. It focuses on the ways in which informal traders active in the city use technology. Actor-network theory was used in the analysis of the field work, uncovering material and human actors, network stabilization processes and agency in determining the transformative potential of this form of digital networking at city and local scales. Findings indicate that appropriation of technology is informed by livelihood strategies. Innovation is enabled when translation extends to appropriation. More in-depth research is needed on how technology is molded and appropriated to suit livelihoods. Throughout the research the spatial dimensions of the relationship between mobile telephony and networks were considered. The network spaces that emerge from actor relations do not correspond with the physical spaces usually considered in policy

Elite land grabbing in Namibian communal areas and its impact on subsistence farmers’ livelihoods

This brief examines some emerging trends and dynamics in changing power relations in rural Namibian communities due to emerging new elites and the threats to subsistence farmers’ access to communal land and natural resources.Australian Development Cooperatio

Current practices for estimation of strength and deformation properties of weak rock masses for geotechnical applications

A Research Report submitted to the Faculty of Engineering and the Built Environment, University of the Witwatersrand, Johannesburg, in partial fulfillment of the requirements for the degree of Master of Science in Engineering (Rock Engineering) Johannesburg, 2018A weak rock mass comprises a collection of material with diverse characteristics and there is thus no single description for weak rock masses. This report summarises developments made in the understanding of weak rock mass, based on measurable parameters. Available tests predominantly measure the compressional strength of intact rock material. The shear strength is then estimated through existing failure criteria, since it is very difficult to obtain the shear strength of rock directly. Wiid (1981) offered an alternative testing technique, ideal for the measurement of shear strength of very soft to soft rock, in the form of a modified vane shear test and this technique is explored further in this report. Additionally, current modelling practices for rock masses generally consider shear strength criteria. However, unexpected failures in major excavations indicate the importance of damage mechanics and the presence of tensile strains in the rock (mass). Through correlations between measurable parameters, a conceptual model for rock strength, is suggested.MT 201

Repair of prestressed concrete bridges : stress distribution and prestressing losses

Today we are faced with the problem of a growing number of existing prestressed concrete bridge structures that are in need of repair work. With prestressed concrete in particular, it is difficult to anticipate how the stress distribution in an existing structure will be affected by the removal or addition of concrete due to repair work. With the impending implementation of Eurocode in Europe, the development of suitable calculation methods on how to deal with this problem in accordance with the standard scripture, are compelling. This thesis is part of a larger project, which will develop suitable methods for the evaluation of damages on bridges, and suitable repair work, in accordance with Eurocode. This thesis investigates the effect of repair work on a prestressed concrete bridge beam. The repair work constitutes the removal of old and/or damaged concrete and the addition of new concrete to repair the damage. The consequences of the repair work is investigated and presented by looking closely at the stress distribution in the cross section, and the losses in prestressing over a time-period of 100 years from construction. Concrete creep and shrinkage are taken into account, as well as prestressing steel relaxation. The results indicate that quite extensive repair procedures can be carried out without severe consequences to the structure. The time of the repair procedure is the most crutial to the structure, as large changes in stress are obtained when concrete is removed and replaced. The detrimental effects on the structure are more prominent the more extensive the repair procedure is

Cardiopulmonary-cerebral resuscitation

No Abstrac

Integrated Development Planning: an opportunity for planners to enable transformation?

Integrated development planning has become synonymous with post-Apartheid development planning. As a style of strategic planning that departs from the master planning models of the past, the preparation of Integrated Development Plans (IDPs) represents a more flexible model for responding to the many challenges that face local authorities. Furthermore, integrated development planning represents an opportunity to forge a stronger relationship between planning and implementation, something, some would argue, that planners have generally been seen to be weak at achieving in the past. Thus, a number of expectations are identifiable with the preparation of IDPs, not least the need to transform local government. This article interrogates the extent to which integrated development planning has enabled transformation in the post-1994 planning and development arena. It specifically looks at the role of the planner in this regard: has integrated development planning as a methodology, as a product (the IDP) and as an approach to planning, enabled the planning profession to contribute to transformation? This question is considered using research that focussed mainly on KwaZulu-Natal, and seeks to clarify some of the dimensions of the relationship between planning, transformation and integrated development planning.&nbsp

Kalsium vir die behandeling van beenkrampe tydens swangerskap

In an attempt to evaluate the aetiology and therapy of leg cramps during pregnancy. patients at an antenatal clinic were treated with calcium or a placebo. The cramps were also evaluated clinically. It was found that calcium and placebo gave the same results and it is suggested that a study be made of ionised calcium levels during pregnancy.S. Afr. Med. J., 48, 780 (1974)