• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 5
  • 5
  • Tagged with
  • 14
  • 8
  • 7
  • 7
  • 6
  • 4
  • 4
  • 4
  • 3
  • 3
  • 2
  • 2
  • 2
  • 2
  • 2
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Aquatic health assessment of the Klip River System, Gauteng, South Africa

Mahlangu, Sikhumbuzo Emmanuel 01 July 2014 (has links)
M.Sc. Aquatic Health) / The Klip River runs past heavy urbanization and industrialization as a consequence it is possibly one of the most abused river systems in Gauteng and perhaps the country as a whole. Eight sites were selected along the course of the Klip River for biomonitoring purposes. The sites were selected to represent the upper, middle and lower reaches of the river, while sites representing point source pollution sources were also included. Various biomonitoring techniques have been included to determine the present ecological state of the Klip River. This includes biotic indices to assess the ecological integrity of the fish and invertebrate communities and the habitat. In addition, fish health was assessed using a variety of histological, biomarker and bioaccumulation based assessments. From the results it is evident that the sites on the Klip River represent the three main regions of a river including headwaters, middle reaches and a mature river. These natural changes in river ecology also caused natural variations in the habitat availability and the resultant biotic communities. There were, however, many changes not related to these natural variations but rather the numerous anthropogenic activities present on the river. The most noticeable change has occurred due to alteration in the flow regime. These changes are brought about by the many weirs and bridges in the system, return flow from the numerous settlements and agricultural activities and the various WWTW. These alterations in flow have caused serious erosion of the stream banks and may lead to siltation of the system. It is clear from the results of the sediment particle size analysis that there is an increase in the percentage contribution of medium and very fine sand below site 3. This is a good indication that the increased flow below the Olifantsvlei WWTW is already causing siltation. Ultimately this can lead to loss of riffle habitat within the river. These flow alterations have also caused an alteration to habitat availability and quality and as a result caused a modified invertebrate community. The macroinvertebrate community at all the sites (below site 1) consisted of taxa that are tolerant to pollution. This is also reflected in the poor SASS 5 and ASPT scores observed at the various sites. These tolerant organisms probably occur in the system due to an altered habitat template and a change in water quality. It is important to note that although the values obtained for the water quality variables are within the TWQR that the oxygen saturation at some sites decreased. These sites included the sites below the Olifantsvlei WWTW, after the confluence with the Rietspruit and the last monitoring site. The Fish Health Assessment Index scores were the highest at site 3 and decreased to site 8. This indicated that the fish condition improved from site 3 to site 8. However, there was a large variation in the index scores from the individual specimens. The results of this assessment cannot be compared to other studies as no fish health assessment index has been applied on the Klip River. This study will serve as a baseline assessment for future studies of the fish health of the Klip River. The results of the metal analysis in the fish muscle tissue indicated relatively low levels that correspond to levels measured by Kotze (1999) while still being lower than fish sampled from the polluted Olifants River. It is therefore recommended that further studies be completed on the fish health of the Klip River and that the fish health of specimens in the Klip River is compared to those of the Vaal River to determine the impact of the Klip River system on the Vaal River. As it has become clear that the Rietspruit also influences the water quality of the Klip River it is recommended that further studies be completed on the Rietspruit to determine the cause of the impacts. Because the histological alterations identified may be the result of a range of different biological and/or chemical stressors, it is difficult to assign specific causative agents for the various alterations identified. Based on the selected parameters investigated, the results show that fish in the Klip River appears to be in a relatively healthy condition and the organs seem to be in a functional state. Establishing a histology-based monitoring programme for fish health in the Klip River, by incorporating appropriate sample sizes and various fish species is recommended. Monitoring of biological responses for assessing the significance of pollutants has become a reasonable measurement in biomonitoring, and use of biomarker responses has played a significant role in this aspect. However, no biomarker has been validated as a unique tool to determine the effects of pollutants on organisms. Furthermore, it is necessary to understand how bioaccumulation and biomarkers relate to each other on exposure to specific pollutants and how it varies between species, to interpret the effects of pollutant exposure in both the field and laboratory. The results obtained in this study indicate that there are definite impacts on the entire system, although these have not altered fish biology and functionality to a large extent. However, sample size should be considered when evaluating individual biomarker responses, as a larger sample size will be more representative of the resident fish community’s response to the pollutants and other stressors. It is difficult to assign specific stressors for the various biomarker responses identified. It is recommended that further biomarker studies be undertaken on the Klip River to increase the level of confidence in the results obtained.
2

Water quality in the upper Klip River, Region 5, City of Johannesburg

Kruger, Welna 05 February 2009 (has links)
M.Sc. / The main aim of this study is to determine the water quality of water sampling points situated in Region Five of The City of Johannesburg. The water quality is studied over a three-year period from July 2000 until June 2003; this includes a dry, normal and rainy year. Region Five falls within the Upper Klipriver sub-catchment, which forms part of the Klip river catchment. The physical, chemical and microbiological sampling results are obtained from Rand Water. These results are compared with the water quality guidelines as set by the Department of Water Affairs and Forestry namely for domestic use, recreational use and aquatic ecosystems, as well as the guidelines set by Rand Water. These results of the variables that were selected are depicted visually in the form of graphs. A scientific approach is followed with respect to the water quality results. The significance of the data is statistically evaluated by using the Student’s t-test. The seasons are divided into two groups namely the more dry and cool season (autumn/winter) and the more rainy and hot season (spring/summer). This is done to determine if the seasons have a significant effect on the water quality results in comparison to each other. The water quality results are then discussed with respect to the different sampling sites. Sampling point K9, the stream at Durban Roodepoort Deep mine delivered the most problematic results of the different sampling points studied, and indicated that acid mine drainage was taking place during the sampling period. The other sampling points are less problematic. Point and non-point source pollution are elaborated on, and recommendations are made to improve the water quality at the sampling points selected.
3

High-contrast imaging in the cloud with klipReduce and Findr

Haug-Baltzell, Asher, Males, Jared R., Morzinski, Katie M., Wu, Ya-Lin, Merchant, Nirav, Lyons, Eric, Close, Laird M. 08 August 2016 (has links)
Astronomical data sets are growing ever larger, and the area of high contrast imaging of exoplanets is no exception. With the advent of fast, low-noise detectors operating at 10 to 1000 Hz, huge numbers of images can be taken during a single hours-long observation. High frame rates offer several advantages, such as improved registration, frame selection, and improved speckle calibration. However, advanced image processing algorithms are computationally challenging to apply. Here we describe a parallelized, cloud-based data reduction system developed for the Magellan Adaptive Optics VisAO camera, which is capable of rapidly exploring tens of thousands of parameter sets affecting the Karhunen-Loeve image processing (KLIP) algorithm to produce high-quality direct images of exoplanets. We demonstrate these capabilities with a visible-wavelength high contrast data set of a hydrogen-accreting brown dwarf companion.
4

The ecological integrity of the Klip River and the development of a sensitivity weighted fish index of biotic integrity (SIBI)

Kotze, P. J. 13 October 2008 (has links)
Ph.D. / The primary objective of the study was to determine the ecological integrity of the Klip River. The protocols applied during the study gave a reliable and good reflection of the overall ecological integrity, as well as the state of different components determining the overall integrity. The ecological integrity of the most recent assessment (February 1999) is summarized in Figure 8.2. It was decided to keep the different components determining ecological integrity (physico-chemical, physical, biological) separate and not to combine everything into one score. When expressed separate, such as in the case of Figure 8.2, it is possible to observed deterioration in overall ecological integrity at a site, and it is also evident which of the components are responsible for the degradation. As mentioned previously, biological communities, and thus biotic integrity, are the best indicators of overall ecological integrity, due to the fact that they integrate both water and habitat related stresses over time. Habitat and water quality assessments are indications of the conditions prevailing at the time of sampling, while biota give an indication of the conditions prevailing over the long term. Invertebrates have shorter life cycles, and in many cases have a terrestrial phase, therefore they recolonise quicker than fish may be able to do after a pollution incident. Invertebrates can therefore be seen as indicators of short-term biological integrity, while fish indicate long-term biological integrity of a river. / Prof. G.J. Steyn
5

Evaluation of the impacts of municipal wastewater treatment on the receiving environment : a case study of the Olifantsvlei wastewater treatment plant in the Gauteng Province, South Africa

Mothetha, Matome Lucky 03 1900 (has links)
South Africa is water scarce country with maximum rainfall received in the summer season which lasts for only three months (November, December and January); hence the water resources have to be protected. The municipal wastewater effluents are considered one of the environmental threats that impact the water quality of the streams. This study was conducted to assess the environmental impact that the wastewater effluent has on the Klip River system, the performance of the plant and also to assess the spatial and temporal variations of water quality along the Klip River system.The study focused mainly on historical data over a five period (2009 – 2013) years secondary data which was analysed by Johannesburg Water Ltd (Pty) and primary data were also collected and analysed using the standard methods of laboratory analysis. The standard methods used include Ion selective electrode, gravimetric techniques, iodemetric titration, membrane filtration method; colorimetric method, automated flow injection method and inductively coupled plasma atomic emission spectrometry (ICP – AES). The aim of collecting the primary data during the dry and wet seasons was to verify the secondary data. The data set was further analysed using multivariate techniques such as principal component analysis (PCA), factor analysis (FA) and discriminant analysis (DA) to determine the spatial and temporal variation of water quality. The data set using ten water quality parameters (ammonia, sulphates, Chlorine, Chemical Oxygen Demand, conductivity, Escherichia coli, sodium, nitrates, pH and suspended solids) was grouped into four sampling points (influent, effluent, downstream and upstream points) and four seasons.Discriminant analysis of water quality showed that out of ten water quality parameters analysed, only sulphates was a less significant parameter to discriminate between the sampling points. For the temporal variations, eight water quality parameters (ammonium, Chlorine, Conductivity, sodium, nitrates, pH, sulphates and suspended solids are the most significant parameters to discriminate between the four seasons. PCA/FA results highlighted similarities in terms of water quality loading between summer and winter seasons and between the winter and autumn seasons. Summer and winter seasons had strong positive loading in COD, ammonium, suspended solids and E. coli whereas the autumn and spring seasons had strong positive loading in sodium, chlorine and pH. The study further highlighted that the Olifantsvlei Wastewater Treatment Works (WWTW) is effectively treating the wastewater up to the required standards before discharging them into the Klip River system. This study concludes that the Olifantsvlei WWTW does not contribute significant loads of pollutants into the Klip river system. / Environmental Sciences / M. Sc. (Environmental Science)
6

Biochemical and molecular characterization of heavy metal resistant bacteria isolated from the Klip River, South Africa

Chihomvu, Patience January 2014 (has links)
M. Tech. (Department of Biotechnology, Faculty of Engineering and Technology) Vaal University of Technology / The Klip River has suffered severe anthropogenic effects from industrial, agricultural, mining and domestic activities. As a result harmful contaminants such as heavy metals have accumulated in the river, causing microorganisms inhabiting the environment to develop mechanisms to protect them from the harmful effects of the contaminants. The current study deals with the isolation and characterization of heavy metal resistant bacteria isolated from the Klip River Catchment. Water and sediment samples were collected from 6 sites of the Klip River, and the Vaal Barrage (control). In-situ parameters, such as pH, turbidity, salinity, conductivity, temperature and dissolved oxygen were determined. Lead, iron, cadmium, nickel, zinc and copper concentrations of water were determined by atomic absorption spectroscopy. For bacterial analysis sediment and water samples were collected in sterile glass jars and bottles respectively. Heavy metal resistant bacterial isolates were screened on heavy metal constituted Luria Bertani (LB) agar. Biochemical profiles of the isolates were constructed using the API 20E® strips, antibiotic susceptibility tests were done and growth studies were carried out using spectrophotometric methods. The isolates were identified using 16SrDNA sequencing and alignment. A partial sequence of the copper resistance gene pcoA was amplified from strains Lysinibacillus sp. KR25 [KJ935917], and Escherichia coli KR29 [KJ935918]. The pcoR gene was amplified from E. coli (KR29) and the partial sequence for the chromate resistance gene chrB, was amplified from Pseudomonas sp. KR23 [KJ935916]. The gene fragments were then sequenced and translated into protein sequences. The partial protein sequences were aligned with existing copper and chromate resistance proteins in the Genbank and phylogenetic analysis was carried out. The physico-chemical properties of the translated proteins were predicted using the bioinformatics tool Expasy ProtParam Program. A homology modelling method was used for the prediction of secondary structures using SOPMA software, 3D-protein modelling was carried out using I-TASSER. Validation of the 3D structures produced was performed using Ramachandran plot analysis using MolProbity, C-score and TM-scores. Plasmid isolation was also carried out for both the wild type strains and cured derivatives and their plasmid profiles were analysed using gel electrophoresis to ascertain the presence of plasmids in the isolates. The cured derivatives were also plated on heavy metal constituted media. Antibiotic disc diffusion tests were also carried out to ascertain whether the antibiotic resistance determinants were present on the plasmid or the chromosome. The uppermost part of the Klip River had the lowest pH and thus the highest levels of heavy metal concentrations were recorded in the water samples. Turbidity, salinity and specific conductivity increased measurably at Site 4 (Henley on Klip Weir). Sixteen isolates exhibiting high iron and lead resistance (4 mM) were selected for further studies. Antibiotic susceptibility tests revealed that the isolates exhibited multi-tolerances to drugs such as Ampicillin (10 μg/ml), Amoxcyllin (10 μg/ml), Cephalothin acid (30 μg/ml), Cotrimoxazole (25 μg/ml), Neomycin (30 μg/ml), Streptomycin (10 μg/ml), Tetracycline (30 μg/ml), Tobramycin (10 μg/ml) and Vancomycin (30 μg/ml). Growth studies illustrated the effect of heavy metals on the isolates growth patterns. Cadmium and chromium inhibited the growth of most of the microorganisms. The following strains had high mean specific growth rates; KR01, KR17, and KR25, therefore these isolates have great potential for bioremediative applications. Using 16SrDNA sequencing the isolates were identified as KR01 (Aeromonas hydrophila), KR02 (Bacillus sp.), KR04 (Bacillus megaterium), KR06 (Bacillus subtilis), KR07 (Pseudomonas sp), KR17 (Proteus penneri), KR18 (Shewanella), KR19 (Aeromonas sp.), KR22 (Proteus sp.), KR23 (Pseudomonas sp.), KR25 (Lysinibacillus sp.), KR29 (Escherichia coli), KR44 (Bacillus licheniformis) and KR48 (Arthrobacter sp.). Three heavy metal resistance genes were detected from three isolates. The pcoA gene was amplified from strains Lysinibacillus sp KR25, and Escherichia coli KR29; pcoR gene from E. coli KR29 and the chrB gene, from Pseudomonas sp. KR23. The genes encoding for heavy metal resistance and antibiotic resistance were found to be located on the chromosome for both Pseudomonas sp. (KR23) and E.coli (KR29). For Lysinibacillus (KR25) the heavy metal resistance determinants are suspected to be located on a mobile genetic element which was not detected using gel electrophoresis. The translated protein sequence for pcoA_25 showed 82% homology with the copper resistant protein form Cronobacter turicensis [YP003212800.1]. Sequence comparisons between the pcoR partial protein sequence found in E. coli KR29 showed 100% homology with 36 amino acids (which was 20% of the query cover) from a transcriptional regulatory protein pcoR found in E. coli [WP014641166.1]. For the chrB partial protein sequence detected in Pseudomonas sp. (KR23), 97% of the query sequence showed 99% homology to a vitamin B12 transporter btuB in Stenotrophus sp. RIT309.
7

Audiovizuální performance v kontextu digitálního prostředí / Audiovisual performance in the context of digital environment

Kořínek, Tomáš January 2016 (has links)
The goal of this thesis is to describe the influence of technological development on the ways in which the moving image is created and to introduce forms that this medium attains in the area of live audio-visual performances. The theoretical study approaches this topic as a historical overview of technical image, focusing on its connections with music. It thus observes specific creative processes of the avant-garde film and music video and subsequently puts them into the context of current types of moving picture created as a result of software codes. Based on the definitions of digital media's key principles, a theoretical basis is set up and then applied to the description of contemporary forms of audio-visual performances. These principles are also used for the definition of the features of software tools, numeric representations of which make it possible to work with any type of an image as with a set of mathematical functions. The main result of this thesis is thus a presentation of creative possibilities of today's image, which has - thanks to digital devices - disengaged itself from its previous technical limitation and become a fully dynamic element that can be created and modified in real time.
8

An evaluation of the cumulative surface water pollution within the consolidated main reef area, Roodepoort, South Africa

Muruven, Dean Nalandhren 08 1900 (has links)
Surface water pollution is prevalent in numerous areas of central Roodepoort mainly due to gold mining activities. The surface water quality for the Bosmontspruit, Russell’s Stream and the New Canada Dam was assessed from October 2010 to March 2011. Physical, chemical and biological characteristics of the water were determined for 8 monitoring points and the results obtained were compared with the In-stream water quality guidelines for the Klip River catchment and the South African Water Quality Guidelines. A trend noticed throughout the sampling period was the non-compliance in the levels of total dissolved solids (TDS) and dissolved oxygen. The results indicated that concentrations of iron, aluminium, nickel, manganese and potassium were above the limit across the Bosmontspruit and Russell’s stream. There was also significant evidence of excessive faecal coliform and ammonium pollution in the Bosmontspruit. During the monitoring period it was noted that water from these streams were utilised for crop irrigation, bathing, livestock and human consumption and may pose a health hazard due to poor water quality. / Environmental Sciences / M.Sc. (Environmental Science)
9

Modelový animovaný klip pro projektovou výuku výtvarné a hudební výchovy na 2. stupni ZŠ\nl(prakticko-teoretická práce) / Model animated clip for project teaching of Arts and Music at secondary basic schools(practical-theoretical thesis)

MÁŠOVÁ, Anna January 2015 (has links)
This diploma thesis deals with animated clip and its application in teaching process, in particular in arts and music classes at secondary basic school, by means of project methodology. The theoretical part, besides project method, which is the center point of this work, also focuses on history of animated film, together with animated clip and its asset. Subsequently, the final section of the practical part applies the findings of the theoretical part. The final section of this diploma thesis is a model animated clip Adebars Reise "The Flight of a Stork" and a draft for the project education in arts and music education at secondary basic school, on the topic of animated clip.
10

An evaluation of the cumulative surface water pollution within the consolidated main reef area, Roodepoort, South Africa

Muruven, Dean Nalandhren 08 1900 (has links)
Surface water pollution is prevalent in numerous areas of central Roodepoort mainly due to gold mining activities. The surface water quality for the Bosmontspruit, Russell’s Stream and the New Canada Dam was assessed from October 2010 to March 2011. Physical, chemical and biological characteristics of the water were determined for 8 monitoring points and the results obtained were compared with the In-stream water quality guidelines for the Klip River catchment and the South African Water Quality Guidelines. A trend noticed throughout the sampling period was the non-compliance in the levels of total dissolved solids (TDS) and dissolved oxygen. The results indicated that concentrations of iron, aluminium, nickel, manganese and potassium were above the limit across the Bosmontspruit and Russell’s stream. There was also significant evidence of excessive faecal coliform and ammonium pollution in the Bosmontspruit. During the monitoring period it was noted that water from these streams were utilised for crop irrigation, bathing, livestock and human consumption and may pose a health hazard due to poor water quality. / Environmental Sciences / M.Sc. (Environmental Science)

Page generated in 0.0214 seconds