Biological aspects of the Permian dicynodont Oudenodon (Therapsida: Dicynodontia) deduced from bone histology and cross-sectional geometry

Main articleBone histology and cross-sectional geometry were used to examine the growth patterns and lifestyle habits of the Late Permian dicynodont, Oudenodon. Several limb bones were analysed, revealing rapidly deposited fibro-lamellar bone, interrupted by annuli or sometimes Lines of Arrested Growth. Peripheral slowly deposited parallel-fibred bone was observed in several elements. It is suggested that the initial growth of Oudenodon was rapid during the favourable growing season, but decreased or sometimes ceased completely during the unfavourable season. Growth was cyclical and may have been sensitive to environmental fluctuations. The slowly forming parallel-fibred bone towards the sub-periosteal surface in several elements indicates a permanent transition to slow growth and may reflect the onset of sexual maturity. Bone cross-sectional geometry results reveal a markedly thick cortex, indicating a possible modification for digging. These cross-sectional geometry values, in conjunction with the limb morphology, suggest that Oudenodon was fossorial.National Research Foundation, South Africa GUN 2061695

In Silico and In Vitro Investigation into the Next Generation of New Psychoactive Substances

New Psychoactive Substances (NPS) were designed to be legal alternatives to existing established recreational drugs. They have fast become a very popular and up until 2016, NPS were legal, cheap and freely accessible via the internet and high street “head shops”. The rapid expansion in the number of these drugs has reached epidemic proportions, whereby hundreds of NPS have been developed and sold within the last five-year period. As NPS are synthesized in clandestine laboratories there is little to no control in the manufacture, dosage and packaging of these drugs. The public health risks posed by these drugs are therefore far-reaching. Fatalities and severe adverse reactions associated with these compounds have become an ongoing challenge to healthcare services, primarily because these drugs have not previously been abused and therefore there is little pharmacological information available regarding NPS. There are a number of different biological receptors that are implicated in the effects of NPS and the mechanism of action for the majority of these drugs is still largely unknown. It is of great importance to try and establish an understanding of how various classes of NPS interact on a molecular level. In this thesis, structure-based and ligand-based in Silico methodologies were employed to gain a better understanding of how NPS may interact with monoamine transporters (MAT). Key findings included both molecular docking studies and a number of robust and predictive QSAR models for the dopamine and serotonin transporters provided insight into how promiscuity of NPS between the different MAT isoforms could arise. In addition, pharmacophore models were generated to identify chemical entities that were structurally dissimilar to known existing NPS that had the potential to interact with the cannabinoid 1 receptor (CB1) and hence were hypothesised could elicit similar biological responses to known potent synthetic cannabinoids. Thirteen of these compounds were identified and carried forward for in vitro and ex vivo analyses, where preliminary results have shown that two compounds activate the CB1 receptor. Further optimisation of these compounds could yield a novel SC scaffold that was previously unseen. Additionally, the compounds identified and the methodology employed in the generation of these new chemical scaffolds could be used to guide Early Warning Systems (EWS) and facilitate law enforcement with respect to emergent NPS

Growth and life habits of the Triassic cynodont Trirachodon, inferred from bone histology

Growth pattern and lifestyle habits of the Triassic non−mammalian cynodont Trirachodon are deduced from bone histol−ogy and cross−sectional geometry. Several skeletal elements of Trirachodon were examined in order to document histological changes during ontogeny, as well as histovariability in the skeleton. The bone histology of all the elements consists of a moderately vascularized, periodically interrupted, fibro−lamellar bone tissue. This suggests that the overall growth of Trirachodon was probably rapid during the favourable season, but decreased or ceased during the unfavourable season. As the environment is thought to have been semi−arid with seasonal rainfall, it is possible that Trirachodon was sensitive to such environmental fluctuations. Some inter−elemental histovariability was noted where the number and prominence of growth rings varied. Limb bone cross−sectional geometry revealed a relatively thick bone wall and sup−ports earlier proposals that Trirachodon was fossorial

Bone microstructure and the evolution of growth patterns in Permo-Triassic therocephalians (Amniota, Therapsida) of South Africa

Therocephalians were a speciose clade of nonmammalian therapsids whose ecological diversity and survivorship of the end-Permian mass extinction offer the potential to investigate the evolution of growth patterns across the clade and their underlying influences on post-extinction body size reductions, or ‘Lilliput effects’. We present a phylogenetic survey of limb bone histology and growth patterns in therocephalians from the Middle Permian through Middle Triassic of the Karoo Basin, South Africa. Histologic sections were prepared from 80 limb bones representing 11 genera of therocephalians. Histologic indicators of skeletal growth, including cortical vascularity (%CV) and mean primary osteon diameters (POD), were evaluated in a phylogenetic framework and assessed for correlations with other biologically significant variables (e.g., size and robusticity). Changes in %CV and POD correlated strongly with evolutionary changes in body size (i.e., smaller-bodied descendants tended to have lower %CV than their larger-bodied ancestors across the tree). Bone wall thickness tended to be high in early therocephalians and lower in the gracile-limbed baurioids, but showed no general correlation with cross-sectional area or degree of vascularity (and, thus, growth). Clade-level patterns, however, deviated from previously studied within-lineage patterns. For example, Moschorhinus, one of few therapsid genera to have survived the extinction boundary, demonstrated higher %CV in the Triassic than in the Permian despite its smaller size in the extinction aftermath. Results support a synergistic model of size reductions for Triassic therocephalians, influenced both by within-lineage heterochronic shifts in survivor taxa (as reported in Moschorhinus and the dicynodont Lystrosaurus) and phylogenetically inferred survival of small-bodied taxa that had evolved short growth durations (e.g., baurioids). These findings mirror the multi-causal Lilliput patterns described in marine faunas, but contrast with skeletochronologic studies that suggest slow, prolonged shell secretion over several years in marine benthos. Applications of phylogenetic comparative methods to new histologic data will continue to improve our understanding of the evolutionary dynamics of growth and body size shifts during mass extinctions and recoveries

The viability of conservation and social forestry outreach nurseries in South Africa

Student Number : 9713352V - PhD thesis - School of Animal, Plant and Environmental Studies - Faculty of ScienceOver 75 nurseries have been implemented by South African state and non-governmental organisations (NGOs) in conjunction with local stakeholders over the past two decades in attempts to achieve a range of natural resource management (NRM) and social responsibility objectives. Despite occasional successes, numerous projects have failed or struggled to achieve their objectives for prolonged periods. This study aims to identify critical factors influencing the viability of outreach nurseries in South Africa through an evaluation of existing and past projects, and to assess the impact of the projects on the lives of community participants. The central questions of the study are: (i) What factors influence the survival of outreach nurseries? (ii) How did these projects affect the different stakeholders, in particular, community participants? (iii) Are outreach nurseries the best means of achieving conservation and socioeconomic goals? (iv) If so, how can project implementation be improved? Outreach nurseries are defined as decentralised nurseries that are established and managed by one or more community participants with varying degrees of support from implementing organisations. The nurseries included in this study are limited to those with NRM objectives. The key issues affecting the development of outreach projects are reviewed, starting with a brief overview of the evolution of people-centred approaches to NRM. Disentangling the complex inter-related political, socioeconomic and environmental factors influencing the development of even small-scale projects such as outreach nurseries is challenging at both research and implementation levels. A model adapted from Choucri (1999) is presented to facilitate the assessment of projects and the assumptions on which they are based by deconstructing the key dimensions of sustainability: ecology, economic activity, political behaviour, governance and institutional performance. An evaluation of 65 South African outreach nurseries was initially conducted. Biophysical problems such as a lack of water, inadequate infrastructure, poor soils, insufficient space and steep slopes were commonly experienced. Unlike small-scale nurseries in India and other parts of Africa, which are often implemented to meet subsistence needs, South African projects frequently include financial objectives to enable the enterprise to become independent of external funding and generate incomes for community participants. Protracted business difficulties were experienced by 68% of the nurseries. Apart from struggling to develop steady markets, nurseries were often located far from markets and were hampered by inadequate transport, pricing difficulties and limited marketing communications. They were also situated in low-income areas where residents have limited spending power. Few thorough viability studies had been carried out and business management skills were restricted, both amongst community participants and practitioners. Ten outreach nurseries with differing profiles and conservation objectives were then assessed in depth. The achievement of financial and NRM objectives was largely sector dependent. These objectives were usually compatible in greening and conservation rehabilitation programmes, facilitating their attainment. Six nurseries aimed to implement greening activities either through their own efforts at local level or by supplying trees to implementing organisations responsible for regional or national greening programmes. Local level greening initiatives included the planting of trees and ornamentals into school grounds and/or and the surrounding community, the establishment and maintenance of a park, the conservation of remnant patches of indigenous vegetation and encouraging local residents to plant indigenous species. At national level, urban municipalities involved in greening initiatives report an 80% survival rates of transplanted seedlings but high mortalities are frequently experienced in rural areas, mainly due to lack of aftercare and seedlings being eaten by livestock. However, the rate of transplanting of distributed seedlings is frequently unknown. A monitoring plan needs to be designed and implemented in conjunction with recipient organisations, to ascertain whether resources are being effectively used and identify shortcomings. Two nurseries supplied seedlings to gold mining rehabilitation programmes. In total, 580 000 seedlings were transplanted onto 437 ha. of gold mining tailings dams and polluted land between 2002 and 2004. One nursery sold just under 35 000 seedlings to this sector in 2005/6. Initial restoration results have been encouraging, with vegetation on some gold tailings dams establishing so well that a new challenge has arisen: viz. encouraging the neighbouring community to harvest at sustainable levels. A nursery established to supply seedlings to alien plant and wetland rehabilitation programmes closed, but this sector has a similar potential to the gold mining rehabilitation programmes to contribute to biodiversity conservation and enhance ecosystem services whilst contributing to local livelihoods. Both require high volumes of inexpensive, fast growing and resilient seedlings. An endangered species nursery had not yet achieved anticipated conservation returns eight years after its inception, mainly due to an extremely difficult sociopolitical local terrain. Incidents of illegal harvesting of a wild population growing near the project site had declined, but conservation officials were concerned that a general increase in the illegal wildlife trade in South Africa would further pressurize this and other species, for example, those valued for their medicinal properties. Medicinal plant nurseries struggled to simultaneously achieve conservation and socioeconomic objectives. Despite concerted efforts for 6-10 years, none achieved their primary goal at even the scale of the participating group viz. to reduce harvesting levels of wild plant populations. Community participants from two nurseries cultivated medicinal plants at the project site and in their home gardens. Approximately 235 medicinal species were cultivated by 31 participants from one nursery (6-64 species per garden; mean+SE=36.5+2.9), but most people continued to use the same volumes of wild collected material as they had prior to the start of the project. However, six years after the last consistent inputs to the project, several influential traditional healers reported that they still cultivated sufficient volumes to meet their needs, no longer harvested from the wild and seldom purchased plant products from markets. Although this is a promising start, efforts need to be considerably scaled up if regional harvesting levels are to be substantially reduced. Harvesting levels in the other project increased due to beneficiating activities, although practitioners urged the group to harvest leaves rather than bark. A third nursery attained financial viability by marketing its products to the horticultural sector. Traditional healers could not afford the prices asked for plants. The impacts of outreach nurseries on community participants depended largely on whether objectives were achieved, whether costs disproportionately outweighed benefits and the nature of relations between participants and staff from implementing organisations. Although non-monetary benefits were important, almost all community participants aspired to earn financial benefits. However, it took 5-10 years for three nurseries to start generating regular financial returns and only two had generated enough to pay participants consistently. Only 9% of the participants who had been involved in projects from the start derived an income. Costs such as time, money and labour substantially outweighed material benefits. Despite high drop out rates, many people persisted as they strongly wanted the project to succeed and feared forfeiting the effort and resources that they had already invested. Participants from projects that had attained their goals gained self confidence, personal satisfaction and respect within the community. Increased knowledge was highly valued, as was local access to seedlings and, in some projects, enhanced food security. However, many participants felt that they had derived no benefits. Material, social and emotional costs were high, particularly where promised funding and support had not materialised. A rapid-results approach was suggested to boost benefits within a reasonable time frame. There was a distinct differentiation in the nature of social relations between community participants and implementing organisations from different sectors. The forestry sector succeeded in balancing task, group maintenance (sound working relationships) and individual needs in most projects, with community participants actively managing or participating in all but one. A regional conservation agency experienced difficulties in achieving individual and group maintenance needs, but had accomplished task needs. Steps had been taken to address the former. Community participants were actively involved in decision making at the time of the interviews. The national conservation agency had not provided support to outreach nurseries in two different provinces, despite being the primary supporting agency in one instance. A practitioner from an NGO displayed group maintenance attributes such as caring and consideration towards community participants, but neither task nor individual needs were met. Problems here appeared to be due to a lack of development experience. Prolonged restructuring of state organisations negatively affected some projects through high staff turnovers, fluctuating policy environments, and low morale and job uncertainty of staff. The operational styles of individuals and supporting organisations strongly influenced the process, as did the socioeconomic and political environment. Authoritarian personalities or organisations exacerbated conflicts while those that operated in a spirit of cooperation managed to resolve differences. Common causes of conflicts between community participants included scarce resources, perceived distributive injustices, jealousies and lack of, or confusion over, accountability. Conflicts spiraled into violence in two projects, and practitioners were threatened with violence in two. Fostering cooperative relationships and operational environments requires a substantial effort from the outset. Ongoing education for both staff and community participants in effectively managing conflict is vital to improve the productivity and longevity of projects, and can sometimes contribute to improved relations in the wider community. This study has highlighted the constraints of outreach nurseries in contributing to the well-being of local stakeholders, particularly when basic development and business fundamentals are not adhered to. Alternate NRM and income generating strategies need to be evaluated during planning as a nursery may not be the best means of achieving either of these. Although small scale and relatively straightforward compared with many ICDPs, outreach nurseries usually require substantial support, including a range of technical, business, and development services. Implementing organisations need to realistically evaluate potential costs and risks to community participants at the outset and determine whether they have the resources and commitment to provide the levels of support that are likely to be required in a project of this nature. Short-term benefits need to be incorporated into planning, and costs mitigated where possible. Project time frames need to be reconsidered, as practitioners estimate that it takes 5–10 years for nurseries to start meeting objectives, and donors and implementing agencies frequently operate on 2–3-year project cycles. Progress needs to be continuously monitored to enable institutions and community participants to adapt to changing conditions and ensure that the spectrum of objectives are being achieved. Cooperative working environments need to be actively fostered and conflict management skills developed, particularly in difficult sociopolitical terrains

The relationship between the leadership, internal quality, and customer satisfaction levels of dealerships in a South African motor vehicle organisation

This research investigates the relationship between the leadership, internal quality, and customer satisfaction levels in the dealerships of a South African motor vehicle organisation. The Service Profit Chain provides the background theory to this relationship, by suggesting that various factors within the service delivery system of an organisation affect the level of customer satisfaction. From the Service Profit Chain, it is established that two of the prevalent factors affecting customer satisfaction, are leadership and internal quality. The Full Range Leadership Development Theory provides the backdrop for analysing the leadership style of each dealership by using the Multifactor Leadership Questionnaire. The Competence Process forms the theoretical construct against which the internal quality of these dealerships is assessed using the Organisation Competence Analysis Questionnaire. Information was gathered, using these two instruments, from a sample of 85 motor vehicle dealerships within South Africa. The customer satisfaction levels at each of these dealerships, is measured by the motor vehicle organisation’s own instrument, known as the Customer Satisfaction Index. Data obtained from each instrument, for the respective dealerships, was then statistically analysed. However, due to the low reliability of the instruments used in this research, the results of this study indicate that there is no relationship between the leadership, internal quality, and customer satisfaction levels within a South African motor vehicle organisation. Therefore we can conclude that the null hypotheses can not be rejected

Tooth replacement patterns in the Early Triassic epicynodont Galesaurus planiceps (Therapsida, Cynodontia)

Sixteen specimens of the Early Triassic cynodont Galesaurus planiceps (including eight that were scanned using micro-computed tomography) representing different ontogenetic stages were assembled to study the dental replacement in the species. The growth series shows that the incisors and postcanines continue to develop and replace, even in the largest (presumably oldest) specimen. In contrast, replacement of the canines ceased with the attainment of skeletal maturity, at a basal skull length of ~90 mm, suggesting that Galesaurus had a finite number of canine replacement cycles. Additionally, the functional canine root morphology of these larger specimens showed a tendency to be open-rooted, a condition not previously reported in Mesozoic theriodonts. An alternating pattern of tooth replacement was documented in the maxillary and mandibular postcanine series. Both postcanine series increased in tooth number as the skull lengthened, with the mandibular postcanine series containing more teeth than the maxillary series. In the maxilla, the first postcanine is consistently the smallest tooth, showing a proportional reduction in size as skull length increased. The longer retention of a tooth in this first locus is a key difference between Galesaurus and Thrinaxodon, in which the mesial-most postcanines are lost after replacement. This difference has contributed to the lengthening of the postcanine series in Galesaurus, as teeth continued to be added to the distal end of the tooth row through ontogeny. Overall, there are considerable differences between Galesaurus and Thrinaxodon relating to the replacement and development of their teeth.Fil: Norton, Luke A.. University of the Witwatersrand; SudáfricaFil: Abdala, Nestor Fernando. University of the Witwatersrand; Sudáfrica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - Tucumán. Unidad Ejecutora Lillo; ArgentinaFil: Rubidge, Bruce S.. University of the Witwatersrand; SudáfricaFil: Botha, Jennifer. Free State University; Sudáfrica. Karoo Palaeontology; Sudáfric

Digging the compromise: investigating the link between limb bone histology and fossoriality in the aardvark (Orycteropus afer)

Bone microstructure has long been known as a powerful tool to investigate lifestyle-related biomechanical constraints, and many studies have focused on identifying such constraints in the limb bones of aquatic or arboreal mammals in recent years. The limb bone microstructure of fossorial mammals, however, has not been extensively described. Furthermore, so far, studies on this subject have always focused on the bone histology of small burrowers, such as subterranean rodents or true moles. Physiological constraints associated with digging, however, are known to be strongly influenced by body size, and larger burrowers are likely to exhibit a histological profile more conspicuously influenced by fossorial activity. Here, we describe for the first time the limb bone histology of the aardvark (Orycteropus afer), the largest extant burrowing mammal. The general pattern is very similar for all six sampled limb bones (i.e., humerus, radius, ulna, femur, tibia, and fibula). Most of the cortex at midshaft is comprised of compacted coarse cancellous bone (CCCB), an endosteal tissue formed in the metaphyses through the compaction of bony trabeculae. Conversely, the periosteal bone is highly resorbed in all sections, and is reduced to a thin outer layer, suggesting a pattern of strong cortical drift. This pattern contrasts with that of most large mammals, in which cortical bone is of mostly periosteal origin, and CCCB, being a very compliant bone tissue type, is usually resorbed or remodeled during ontogeny. The link between histology and muscle attachment sites, as well as the influence of the semi-arid environment and ant-eating habits of the aardvark on its bone microstructure, are discussed. We hypothesize that the unusual histological profile of the aardvark is likely the outcome of physiological constraints due to both extensive digging behavior and strong metabolic restrictions. Adaptations to fossoriality are thus the result of a physiological compromise between limited food availability, an environment with high temperature variability, and the need for biomechanical resistance during digging. These results highlight the difficulties of deciphering all factors potentially involved in bone formation in fossorial mammals. Even though the formation and maintaining of CCCB through ontogeny in the aardvark cannot be unambiguously linked with its fossorial habits, a high amount of CCCB has been observed in the limb bones of other large burrowing mammals. The inclusion of such large burrowers in future histological studies is thus likely to improve our understanding of the functional link between bone growth and fossorial lifestyle in an evolutionary context

Exploring the feasibility of using mobile phones to improve the management of clients with cervical cancer precursor lesions

Abstract Background Cancer screening programs hold much potential for reducing the cervical cancer disease burden in developing countries. The aim of this study was to determine the feasibility of mobile health (mHealth) phone technology to improve management and follow-up of clients with cervical cancer precursor lesions. Methods A sequential mixed methods design was employed for this study. Quantitative data was collected using a cross-sectional survey of 364 women eligible for a Pap smear at public sector health services in Cape Town, South Africa. Information was collected on socio-demographic status; cell phone ownership and patterns of use; knowledge of cervical cancer prevention; and interest in Pap smear results and appointment reminders via SMS-text messages. Descriptive statistics, crude bivariate comparisons and logistic regression models were employed to analyze survey results. Qualitative data was collected through 10 in-depth interviews with primary health care providers and managers involved in cervical cancer screening. Four focus group discussions with 27 women attending a tertiary level colposcopy clinic were also conducted. Themes related to loss of mobile phones, privacy and confidentiality, interest in receiving SMS-text messages, text language and clinic-based management of a SMS system are discussed. Thematic analyses of qualitative data complemented quantitative findings. Results Phone ownership amongst surveyed women was 98% with phones mostly used for calls and short message service (SMS) functions. Over half (58%) of women reported loss/theft of mobile phones. Overall, there was interest in SMS interventions for receiving Pap smear results and appointment reminders. Reasons for interest, articulated by both providers and clients, included convenience, cost and time-saving benefits and benefits of not taking time off work. However, concerns were expressed around confidentiality of SMS messages, loss/theft of mobile phones, receiving negative results via SMS and accessibility/clarity of language used to convey messages. Responsibility for the management of a clinic-based SMS system was also raised. Conclusions Results indicated interest and potential for mHealth interventions in improving follow-up and management of clients with abnormal Pap smears. Health system and privacy issues will need to be addressed for mHealth to achieve this potential. Next steps include piloting of specific SMS messages to test feasibility and acceptability in this setting