Many parts of the world, but South Africa specifically, are facing a water crisis, not only because of the scarcity of water, but also the quality of the water that is available. Companies are the primary users of water and can therefore have the most significant impact on saving water. It is thus imperative to determine how companies are measuring, managing, engaging with their stakeholders and disclosing water-related risks in their businesses. This study was conducted on the premise that South African companies have not as yet grasped the seriousness of the water crisis. Thirty JSE-listed companies classified as being water intensive were selected for the study. Their sustainability/integrated/annual reports for 2011 and 2013 were downloaded from the internet and analysed to determine if and how they were mitigating their water-related risks. The Ceres Aqua Gauge™ was used as the framework for this study. It was established during the analysis of the selected companies’ reports that, with the exception of food producers and food retailers, the companies had grasped the seriousness of the water crisis. One area of particular concern that was evident in all the companies was the lack of attention directed towards supply chain water management. Companies need to address water risks in their supply chain, and to also turn the water crisis from a threat into an opportunity. Investors need to engage with and put pressure on companies to improve their water management practices. / Business Management / M. Ph. Accounting Sciences (Management Accounting)

Here I study the “plasma interactions with icy bodies in the solar system”, that is, my quest to understand the fundamental processes that govern such interactions. By using numerical modelling combined with in situ observations, one can infer the internal structure of icy bodies and their plasma environments. After a broad overview of the laws governing space plasmas a more detailed part follows. This contains the method on how to model the interaction between space plasmas and icy bodies. Numerical modelling of space plasmas is applied to the icy bodies Callisto (a satellite of Jupiter), the dwarf planet Ceres (located in the asteroid main belt) and the comet 67P/Churyumov-Gerasimenko. The time-varying magnetic field of Jupiter induces currents inside the electrically conducting moon Callisto. These create magnetic field perturbations thought to be related to conducting subsurface oceans. The flow of plasma in the vicinity of Callisto is greatly affected by these magnetic field perturbations. By using a hybrid plasma solver, the interaction has been modelled when including magnetic induction and agrees well with magnetometer data from flybys (C3 and C9) made by the Galileo spacecraft. The magnetic field configuration allows an inflow of ions onto Callisto’s surface in the central wake. Plasma that hits the surface knocks away matter (sputtering) and creates Callisto’s tenuous atmosphere. A long term study of solar wind protons as seen by the Rosetta spacecraft was conducted as the comet 67P/Churyumov-Gerasimenko approached the Sun. Here, extreme ultraviolet radiation from the Sun ionizes the neutral water of the comet’s coma. Newly produced water ions get picked up by the solar wind flow, and forces the solar wind protons to deflect due to conservation of momentum. This effect of mass-loading increases steadily as the comet draws closer to the Sun. The solar wind is deflected, but does not lose much energy. Hybrid modelling of the solar wind interaction with the coma agrees with the observations; the force acting to deflect the bulk of the solar wind plasma is greater than the force acting to slow it down. Ceres can have high outgassing of water vapour, according to observations by the Herschel Space Observatory in 2012 and 2013. There, two regions were identified as sources of water vapour. As Ceres rotates, so will the source regions. The plasma interaction close to Ceres depends greatly on the source location of water vapour, whereas far from Ceres it does not. On a global scale, Ceres has a comet-like interaction with the solar wind, where the solar wind is perturbed far downstream of Ceres. / Här studerar jag “plasmaväxelverkan med isiga kroppar i solsystemet”, det vill säga, min strävan är att förstå de grundläggande processerna som styr sådana interaktioner. Genom att använda numerisk modellering i kombination med observationer på plats vid himlakropparna kan man förstå sig på deras interna strukturer och rymdmiljöer. Efter en bred översikt över de fysiska lagar som styr ett rymdplasma följer en mer detaljerad del. Denna innehåller metoder för hur man kan modellera växelverkan mellan rymdplasma och isiga kroppar. Numerisk modellering av rymdplasma appliceras på de isiga himlakropparna Callisto (en måne kring Jupiter), dvärgplaneten Ceres (lokaliserad i asteroidbältet mellan Mars och Jupiter) och kometen 67P/Churyumov-Gerasimenko. Det tidsvarierande magnetiska fältet kring Jupiter inducerar strömmar inuti den elektriskt ledande månen Callisto. Dessa strömmar skapar magnetfältsstörningar som tros vara relaterade till ett elektriskt ledande hav under Callistos yta. Plasmaflödet i närheten av Callisto påverkas i hög grad av dessa magnetfältsstörningar. Genom att använda en hybrid-plasma-lösare har växelverkan modellerats, där effekten av magnetisk induktion har inkluderats. Resultaten stämmer väl överens med magnetfältsdata från förbiflygningarna av Callisto (C3 och C9) som gjordes av den obemannade rymdfarkosten Galileo i dess bana kring Jupiter. Den magnetiska konfigurationen som uppstår möjliggör ett inflöde av laddade joner på Callistos baksida. Plasma som träffar ytan slår bort materia och skapar Callistos tunna atmosfär. En långtidsstudie av solvindsprotoner sett från rymdfarkosten Rosetta utfördes då kometen 67P/Churyumov-Gerasimenko närmade sig solen. Ultraviolett strålning från solen joniserar det neutrala vattnet i kometens koma (kometens atmosfär). Nyligt joniserade vattenmolekyler plockas upp av solvindsflödet och tvingar solvindsprotonernas banor att böjas av, så att rörelsemängden bevaras. Denna effekt ökar stadigt då kometen närmar sig solen. Solvinden böjs av kraftigt, men förlorar inte mycket energi. Hybridmodellering av solvindens växelverkan bekräftar att kraften som verkar på solvinden till störst del får den att böjas av, medan kraften som verkar till att sänka dess fart är mycket lägre. Ceres har enligt observationer av rymdteleskopet Herschel under 2012 och 2013 haft högt utflöde av vattenånga från dess yta. Där har två regioner identifierats som källor för vattenångan. Eftersom Ceres roterar kommer källornas regioner göra det också. Plasmaväxelverkan i närheten av Ceres beror i hög grad på vattenångskällans placeringen, medan det inte gör det långt ifrån Ceres. På global nivå har Ceres en kometliknande växelverkan med solvinden, där störningar i solvinden propagerar långt nedströms från Ceres.

The aim of this study is to compare selected episodes of Ovid's Metamorphoses with three works of modern literature containing the theme of metamorphosis, and to follow their intertextual relations, dependency and innovation of Ovidian themes. On the basis of a comparison of the ancient and the modern text it is examined which motives remain constant during centuries and which, on the contrary, are evolving and shifting their meanings. Through the perspective of the Metamorphoses an attempt is made to interpret the works from a less usual angle. The most significant Ovidian characters that are examined in this study are Teiresias, Daphne, Hyacinth, Orpheus, Ceres, Icarus, Callisto and Io.

Many parts of the world, but South Africa specifically, are facing a water crisis, not only because of the scarcity of water, but also the quality of the water that is available. Companies are the primary users of water and can therefore have the most significant impact on saving water. It is thus imperative to determine how companies are measuring, managing, engaging with their stakeholders and disclosing water-related risks in their businesses. This study was conducted on the premise that South African companies have not as yet grasped the seriousness of the water crisis. Thirty JSE-listed companies classified as being water intensive were selected for the study. Their sustainability/integrated/annual reports for 2011 and 2013 were downloaded from the internet and analysed to determine if and how they were mitigating their water-related risks. The Ceres Aqua Gauge™ was used as the framework for this study. It was established during the analysis of the selected companies’ reports that, with the exception of food producers and food retailers, the companies had grasped the seriousness of the water crisis. One area of particular concern that was evident in all the companies was the lack of attention directed towards supply chain water management. Companies need to address water risks in their supply chain, and to also turn the water crisis from a threat into an opportunity. Investors need to engage with and put pressure on companies to improve their water management practices. / Business Management / M. Ph. Accounting Sciences (Management Accounting)

Aerosols affect the global radiation budget which plays an important role in determining the state of the Earth's climate. The heterogeneous distribution of aerosols and the variety in their properties results in high uncertainty in the understanding of aerosols. Aerosols affect the radiation by scattering and absorption (direct effect) or by modifying the cloud properties which in turn affects the radiation (indirect effect). The current work focuses only on the direct radiative effect of aerosols. The change in the top-of-atmosphere (TOA) reflected flux due to the perturbation of aerosols and their properties is called direct aerosol radiative forcing (ARFTOA). Estimation of ARFTOA using aerosol properties is done by solving the radiative transfer equation using a radiative transfer model. However, before using the radiative transfer model, it has to be validated with observations for consistency. This is done to check if the model is able to replicate values close to actual observations. The current work uses the Santa Barbara DISORT Atmospheric Radiative Transfer (SBDART) model. The output radiative fluxes from SBDART are validated by comparing with the Clouds and the Earth's Radiant Energy System (CERES) satellite data. Under clear-skies SBDART agreed with observed fluxes at TOA well within the error limits of satellite observations. In the shortwave solar spectrum (0.25-4 µm) radiation is affected by change in various aerosol properties and also by water vapour and other gas molecules. To study the effect of each of these molecules separately on the aerosol forcing at TOA, SBDART is used. ARFTOA is found to depend on the aerosol loading (aerosol optical depth – AOD), aerosol type (SSA) and the angular distribution of scattered radiation (asymmetry parameter). The role of water vapour relative to the aerosol layer height was also investigated and for different aerosol types and aerosol layer heights, it was found that water vapour can induce a change of ~4 Wm-2 in TOA flux. The relative importance of aerosol scattering versus absorption is evaluated through a parameter called single scattering albedo (SSA) which can be estimated from satellites. SSA defined as the ratio of scattering efficiency to total extinction efficiency, depends on the aerosol composition and wavelength. Aerosols with SSA close to 1 (sea-salt, sulphates) scatter the radiation and cool the atmosphere. Aerosols with SSA < 0.9 (black carbon, dust) absorb radiation and warm the atmosphere. Over high reflective surfaces a small change in SSA can change forcing from negative (cooling) to positive (warming). This makes SSA one of the most important and uncertain aerosol parameters. Currently, the SSA retrievals from the Ozone Monitoring Instrument (OMI) are highly sensitive to sub-pixel cloud contamination and change in aerosol height. Using the sensitivity of OMI to aerosol absorption and the superior cloud masking technique and accurate AOD retrieval of Moderate Resolution Imaging Spectroradiometer (MODIS), an algorithm to retrieve SSA (OMI-MODIS) was developed. The algorithm was performed over global oceans (60S-60N) from 2008-2012. The difference in SSA estimated by OMI-MODIS and that of OMI depended on the aerosol type and aerosol layer height. Aerosol layer height plays an important role in the UV spectrum due to the dominance of Rayleigh scattering. This was verified using SBDART which otherwise would not have been possible using just satellite observations. Both the algorithms were validated with cruise measurements over Arabian Sea and Bay of Bengal. It was seen that when absorbing aerosols (low SSA values) were present closer to the surface, OMI overestimated the value of SSA. On the other hand OMI-MODIS algorithm, which made no assumption on the aerosol type or height, was better constrained than OMI and hence was closer to the cruise measurement The presence of clouds results in a more complex interaction between aerosols and radiation. Aerosols present above clouds are responsible to most of the direct radiative effect in cloudy regions. The ARFTOA depends not only on the aerosol properties but also on the relative position of aerosols with clouds. When absorbing aerosols are present above clouds, the ARFTOA is highly influenced by the albedo of the underlying surface. Recent studies, over regions influenced by biomass burning aerosol, have shown that it is possible to define a ‘critical cloud fraction’ (CCF) at which the aerosol direct radiative forcing switch from a cooling to a warming effect. Similar analysis was done over BoB (6.5-21.5N; 82.5-97.5E) for the years 2008-2011. Aerosol properties were taken from satellite observations. Satellites cannot provide for aerosols present at different heights and hence SBDART was used to calculate the forcing due to aerosols present only above clouds. Unlike previous studies which reported a single value of CCF, over BoB it was found that CCF varied from 0.28 to 0.13 from post-monsoon to winter as a result of shift from less absorbing to moderately absorbing aerosol. This implies that in winter, the absorbing aerosols present above clouds cause warming of the atmosphere even at low cloud fractions leading to lower CCF. The use of multiple satellites in improving the retrieval of SSA has been presented in this thesis. The effect of aerosols present above clouds on the radiative forcing at TOA is shown to be different between Bay of Bengal and Atlantic Ocean. This was due to the change in SSA of aerosols during different seasons. The effect of aerosol height, aerosol type and water vapour on the TOA flux estimation is also studied using a radiative transfer model.