Comparative Taxonomic, Taphonomic and Palaeoenvironmental Analysis of 4-2.3 Million Year Old Australopithecine Cave Infills at Sterkfontein.

Student Number : 0001944J - PhD thesis - School of Geography, Archaeoloy nd Environmental Studies and School of Anatomical Science - Faculty of ScienceThe site of Sterkfontein is rich in fossil deposits spanning different time periods from as early as 4 million years to as recent as 116, 000 years. Stratigraphy, taxonomy, taphonomy, archaeology and palaeoenvironmental analysis from various infills have been under constant review as new materials are recovered from the ongoing excavations. It is the recovery of numerous new fossils that prompted a need for a review into earlier hypotheses, interpretations and conclusions arrived at by earlier researchers on the Member 4 and the Jacovec Cavern infills. New data indicates that the two infills, though spanning different time periods, share similarities but also display marked differences in taxonomy, taphonomy and palaeoenvironment. Taxonomically, the most striking difference between the two deposits is the higher frequency of taxa and species diversity within the Member 4 faunal assemblage than in the Jacovec Cavern faunal assemblage. There are nine bovid tribes represented in five subfamilies within Member 4 and six bovid tribes in three subfamilies within Jacovec Cavern. At least five primate species have been recovered from Member 4 while three primate species have been recovered from the Jacovec Cavern. Twelve carnivore species are represented in Member 4 while eleven are represented in Jacovec Cavern. Some categories of other fauna are limited to the Member 4 infill while others are limited to the Jacovec Cavern infill. Taphonomically, both assemblages are characterized by low frequencies of bone modification. These low frequencies are a result of a culmination of various agents of accumulation and varieties and intensities of postdepositional processes that impacted on the original deposited assemblage prior to recovery. The faunal assemblage in Member 4 was accumulated into the cave through a combination of voiding carnivores, “death trap” and natural death within the cave. The Jacovec Cavern fauna on the other hand was accumulated by carnivores, not in the cavern but on the surface above and within the vicinity of the cave entrance. Eventually fluvial action incorporated the surface materials, including faunal remains into the Jacovec Cavern. Palaeoenvironmental reconstruction indicates a correlation of climatic conditions similar to that derived from analysis of terrigenous sediments off the coast of Africa. For Member 4, palaeoenvironmental reconstruction indicates the existence of a mix of forest and open savannah with more emphasis on woodland, while a mosaic of open grassland and dense forest, equivalent to today’s tropical forest in Africa is suggested for the Jacovec Cavern

Regulation of the Pseudomonas aeruginosa amidase operon by transcription antitermination

Previous studies have identified five genes, amiE (amidase structural gene), amiB, amiC (negative regulator gene), amiR (positive regulator gene) and amiS, in the inducible amidase operon of Pseudomonas aeruginosa. The amidase operon is regulated in part by transcription antitermination upstream of the operon at a Rho-independent terminator located between amiE and its promoter. In this study, the induction of amidase expression and the mechanism of transcription antitermination have been investigated. An inducible amidase expression system has, for the first time, been reconstituted in E. coli by making a coordinate expression vector for amiC and amiR. The amiCIR expression vector was also used to restore an amidase inducible phenotype in a Pseudomonas aeruginosa amidase-constitutive mutant and in an amidase amiC-, amiR- negative mutant. A deletion mutation within the amiB gene, previously thought to be involved in amidase induction, led to no change in amidase phenotype. It is now thought that amiB codes for the energy transducing component of an ABC type transporter system. The sequence of amiS, the potential membrane component of the putative ABC transporter has been confirmed. In an attempt to purify AmiR for in vitro studies of the transcription antitermination mechanism, an AmiR overproducing plasmid has been constructed based on a T7 expression system. AmiR has been expressed using this system to about 20% of total cellular protein. Purification of active protein was, however, not achieved due to poor binding to ion exchange columns and aggregation. Identity of the protein was however confirmed by analysis on SDS-polyacrylamide gels, Western blotting using rabbit antisera raised against an MalE-AmiR fusion and by N-terminal sequencing. The transcription antitermination mechanism has been investigated both in vivo and in vitro. Firstly, overexpression of the leader sequence in trans has been shown to reduce the direct AmiR interaction with the leader mRNA. Secondly, by cloning various lengths of the amidase leader region upstream of amiR followed by in vivo competition studies, it has been shown that AmiR mediates transcription antitermination by binding to the leader transcript within a region that runs up to the terminator upstream face. In vitro RNA/protein interaction studies have been carried out. Bandshift studies showed complex formation between 32p labelled leader RNA and a semipurified E. coli extract containing AmiR. The specific nature of the nucleoprotein complex was demonstrated by cold competition experiments. Bandshift experiments using transcripts encompassing different lengths of the leader region identified a 58b region running from +10 to +68 from the transcription start site as the binding region. The precise binding site was not determined. Extensive site directed mutagenesis within the leader region has identified sequences that are critical for the antitermination reaction without any effect on the termination reaction, and other sequences that made the terminator 'leaky' without any apparent effect on antitermination

Health and Safety Awareness among Employees in State Corporations: The Case Of Kenya Revenue Authority

A Project Report Submitted to the Chandaria School of Business in Partial Fulfillment of the Requirement for the Degree of Executive Masters in Organizational Development (EMOD)The purpose of the study was to determine the level of health and safety awareness among employees at Kenya Revenue Authority (KRA). The specific objectives of the research were to: determine existing occupational health and safety laws, policies and procedures; determine existing occupational health and safety equipment and facilities; and establish the staff preparedness and management in case of occupational health and safety incidents. Descriptive research design was employed focusing on quantitative and qualitative characteristics and status of Occupational Health and Safety (OHS) Policy and management. The target population consisted of all permanent employees working for KRA at the organization’s headquarters (HQs). This study employed the stratified sampling technique to select a cross section of staff at different departments. The sample size of the study was 280 employees (respondents) sampled from all departments at KRA. Primary data was collected primarily using questionnaire that contained both open and closed ended questions. Data collected was first cleaned, sorted and matched, coded and analyzed using the Statistical Package for Social Scientist (SPSS) to obtain descriptive statistics such as means, percentages and frequencies were used to describe the data. The study revealed that there were no significant gaps between policies and actual control of workplace risks at KRA and that, there exists legal requirements that required KRA to put in place mechanisms that ensure employee health and safety. The study shows that KRA managers had the primary responsibility of managing employee safety and health and that the organization provided safety bulletin boards that were used for posting required safety posters and notifications. The study revealed that departments in the organization developed and maintained Emergency Evacuation and Operations Plan (EEOP) that would be used in cases of emergency and employees were trained on departmental emergency plan. The organization provided strategic locations where first aid kits were availed and there designated personnel assigned at different floors who had been trained on first aid and cardiopulmonary resuscitation (CPR). The study shows that organizational culture at KRA encouraged interpretation, improvisation and unique action of employees and the effectiveness of policies in light of management practices and employees’ beliefs were regularly examined. The management support of safety in the organization enhanced subordinate perceptions of the health and safety levels at work and the key determinant of employees’ successful coping was driven by their perception of how much they could control the outcomes of their work environment. It can be concluded that all employees at KRA have been engaged in training on employee health and safety procedures thus placing the organization in a better place in case an emergency occurs. The management support of the OHS indicates the importance of the OHS to employees and the organization in general thus enhancing the implementation of the same. It can be concluded from the study results that KRA as an organization are well versed and trained on OHS. The study recommends KRA to ensure that its OHS program addresses the general requirements specified by OHS legislation as well as outline the objectives and scope of the organization’s OHS program and demonstrate management’s commitment to providing a safe workplace. The study also recommends KRA to ensure that its OHS plan is adjusted to fit the specific risks associated with its business. The organization should also obtain clear verbal and written agreement from all staff that they understand their OHS responsibilities - including OHS policies and procedures - in order to create a “safety culture” among all levels of staff

USING MICROCT TO VISUALIZE NANOFLUID DROPLET SORPTION PROFILES IN UNSATURATED POROUS MEDIA

ABSTRACT Liquid droplet sorption in unsaturated porous media is an important process for a wide range of applications. However, visualizing droplet sorption is difficult due to the opaque nature of porous media used in most of the applications. In this study, microCT is used to characterize the sorption profiles of single/multiple nanofuid droplets in PMMA powder beds. The microCT scan results reveal that the region of the powder bed saturated with nanofluid has a substantially higher gray scale value than that in the unsaturated region, thus enabling the visualization of the sorption profile. It also shows that nanoparticles enhance the visualization of the sorption profiles as they tend to accumulate and stay near the wetting front even after water evaporation