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  • 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.
191

An empirical investigation into Green IT practices in the North West Provincial Government / Tebogo Lucia Letlonkane

Letlonkane, Tebogo Lucia January 2014 (has links)
Climate change has been a topic for discussion in the IT industry. The IT (information technology) sector has been regarded as one of the contributing sectors towards climate change due to carbon emissions from IT equipment such as computers and servers. Environmental concerns are gaining incremental attention from organisations across the globe. Green IT is seen as part of the solution to this problem and has been defined and discussed by many researchers. The purpose of this study was to investigate Green IT practices that have been adopted in the NWPG (North West Provincial Government). The study focused on the three departments which fall under one central IT section in the department of the provincial treasury. A quantitative study was conducted in Mafikeng and questionnaires were distributed to collect the data and it was found that although end-users in the government sector are aware of Green IT, many still needed a lot of training on Green IT. The research concludes by suggesting strategies that might be adopted to improve IT use in the government sector. / Thesis (M.Com.(Information Systems) North-West University, Mafikeng Campus, 2014
192

Implications of global warming for African climate

James, Rachel Anne January 2014 (has links)
A 2°C increase in global mean temperature (ΔTg) has been widely adopted as a benchmark for dangerous climate change. However, there has been a lack of research into the implications of 2°C, or any other degree of warming, for Africa. In this thesis changes in African temperature and precipitation associated with 1°C, 2°C, 3°C, 4°C, and beyond are investigated for the first time, using output from 350 climate model experiments: a collection of simulations from international modelling centres (CMIP3), two Perturbed Physics Ensembles (PPEs), and a group of five regional models. The models project temperature and precipitation anomalies which increase in magnitude and spatial extent as global temperature rises, including a wet signal in East Africa, and drier conditions for African rainforests. The models consistently show that the evolution of change with global warming is gradual, even at 4°C and beyond; but the amplitude and direction of precipitation change at each ΔTg increment vary between models and between datasets. The PPEs project precipitation signals which are not represented by CMIP3, in particular a large drying (>0.5 mm day-1 °C-1) of western Africa. There are also important differences between global and regional models, especially in southern and West Africa (>1 mm day-1). Analysis of atmospheric circulation responses suggests that the higher resolution projections are no more credible in this case. Some of the variation between models can be understood as the result of untrustworthy simulations, leading to constraints on the PPEs, and casting doubt on the strong drying of west Sahel; but model evaluation is found to be limited by observations in the case of the Congo Basin. The implications of global warming are different depending on which models are consulted. The findings emphasise that caution should be exercised in the application of climate model data to inform mitigation debates.
193

Global warming without global mean precipitation increase?

Salzmann, Marc 19 July 2016 (has links) (PDF)
Global climate models simulate a robust increase of global mean precipitation of about 1.5 to 2% per Kelvin surface warming in response to greenhouse gas (GHG) forcing.Here, it is shown that the sensitivity to aerosol cooling is robust as well, albeit roughly twice as large. This larger sensitivity is consistent with energy budget arguments. At the same time, it is still considerably lower than the 6.5 to 7% K−1 decrease of the water vapor concentration with cooling from anthropogenic aerosol because the water vapor radiative feedback lowers the hydrological sensitivity to anthropogenic forcings. When GHG and aerosol forcings are combined, the climate models with a realistic 20th century warming indicate that the globa lmean precipitation increase due to GHG warming has, until recently, been completely masked by aerosol drying. This explains the apparent lack of sensitivity of the global mean precipitation to the net global warming recently found in observations. As the importance of GHG warming increases in the future, a clear signal will emerge.
194

Quantifying the sustainability of the built environment : model for the determination of the environment impact of the end-of-life phase

Brits, Juane 12 1900 (has links)
Thesis (MScEng)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: See item for abstract / AFRIKAANSE OPSOMMING: Sien item vir opsomming
195

Integrating the effects of climate change and caribou herbivory on vegetation community structure in low Arctic tundra

Zamin, Tara 07 June 2013 (has links)
Arctic tundra vegetation communities are rapidly responding to climate warming with increases in aboveground biomass, particularly in deciduous shrubs. This increased shrub density has the potential to dramatically alter the functioning of tundra ecosystems through its effects on permafrost degradation and nutrient cycling, and to cause positive feedbacks to global climate change through its impacts on carbon balance and albedo. Experimental evidence indicates that tundra plant growth is most strongly limited by soil nutrient availability, which is projected to increase with warming. Therefore research to date into the mechanisms driving tundra 'shrub expansion' has taken a 'bottom-up' perspective, overlooking the potential role of herbivory in mediating plant-soil interactions. In this thesis, I integrate the impacts of climate warming and caribou browsing on tundra vegetation community structure, and specifically investigate if increases in soil fertility with warming might lead to changes in vegetation biomass and chemistry that could fundamentally alter herbivore-nutrient cycling feedbacks, shifting the role of caribou browsing from restricting shrub growth to facilitating it. Using experimental greenhouses, nutrient addition plots, and caribou exclosures at Daring Lake Research Station in the central Canadian low Arctic, I showed that warming increased soil nutrient availability and plant biomass, and that caribou browsing restricted tundra shrub growth under present conditions. Plant and soil nutrient pool responses to warming demonstrated that increased growing season temperatures enhanced tundra plant growth both by increasing soil nutrient availability and by inferred increases in the rate of photosynthesis, however that the former process was comparatively more limiting. Species- and plant part-specific changes in biomass and chemistry with warming and fertilization clearly indicated the rate and magnitude of change in soil fertility substantially alters plant community structure. Nonetheless, since plant nutrient concentrations decreased with warming and plant responses to browsing were independent of soil fertility, I did not find evidence for a shift from caribou decelerating to accelerating nutrient cycling with warming. Altogether this research indicates effective conservation and management of Rangifer populations is critical to understanding how climate change will affect tundra vegetation trajectories and ultimately tundra ecosystem carbon balances. / Thesis (Ph.D, Biology) -- Queen's University, 2013-06-07 15:13:21.698
196

Influence of warming on microbial ecosystems

Fussmann, Katarina E. 10 February 2017 (has links)
No description available.
197

Potential for Climate Induced Methane Hydrate Dissociation

MacWilliams, Graham 01 January 2018 (has links)
Methane hydrates are frozen deposits of methane and water found in high pressure or low temperature sediments. When these deposits destabilize, large quantities of methane can be emitted into the atmosphere. This is significant to climate change because methane has 25 times more greenhouse gas potential than Carbon Dioxide. Worldwide, it is estimated there are between 2500 and 10000 gigatons of methane stored in hydrate deposits. This represents more carbon than all fossil fuels on Earth. It is estimated that between 200 and 2000 gigatons of methane are stored in hydrates in Arctic waters acutely vulnerable to greenhouse warming. Over the last decade, researchers have identified instances of hydrate destabilization that have already begun. To gain insight into the potential climatic effects widespread hydrate dissociation would have, researchers have examined hydrate dissociation during the Paleocene Eocene Thermal Maximum 55 million years ago as a geologic precedent. In this period, large-scale hydrate dissociation contributed to 5-8 degree Celsius warming worldwide. If such a climatic shift were to transpire today, impacts on society would be enormous. There is currently a debate in the scientific community as to whether the risk of methane hydrate dissociation is relevant to the present generation. One side argues that not enough methane could be emitted into the atmosphere from today’s hydrate sources to have a meaningful impact on climate warming, where the other side contends that more than enough methane could be emitted from present day hydrate deposits to cause significant impacts to the global greenhouse effect. Given the information currently known about hydrates, it is reasonable to conclude there is a moderate risk of widespread destabilization that could impact global climate change in the coming decades. Significant acceleration of the conversion to alternative energies and implementation of geoengineering strategies should be considered.
198

Förekomsten av hypotermi vid rutinbarnanestesi

Andreas, Persson January 2016 (has links)
Background:  Children going through surgery are likely to develop hypothermia caused by anesthesia, which can have severer consequences both peri and postoperatively. With increased understanding and knowledge regarding the correct methods for prevention, hypothermia caused by anesthesia in children can be reduced. This in turn, will lead to better and safer care. Aim: To describe the presence of hypothermia in children undergoing anesthesia. Also, this study will look at how the nurse anesthetists’ different interventions to preserve heat affect the occurrence of hypothermia. Methods: A descriptive retrospective study was performed. Medical records were reviewed to collect data. Results: The result showed that despite interventions to preserve heat were implemented, hypothermia caused by anesthesia still occurred during surgery. Gender, age and type of operation were factors that did not correlate with the presence of hypothermia. The length of surgery was shown to have some negative correlation with presence of hypothermia. Nursing interventions to preserve heat had no significant association with hypothermia. Conclusions: Nurse anesthetist used different combinations of interventions to preserve heat and reduce the risk for hypothermia in children. The majority of children obtained three or more different interventions aimed to preserve heat. Despite this, several children developed hypothermia during surgery. By increasing the nurse anesthetists’ knowledge and awareness regarding hypothermia caused by anesthesia, it can lead to improvement in providing safe care and reduce the number of cases where hypothermia occurs. Continued similar studies could lead to more person-centered care with personalized policies and amend the methods used regarding hypothermia caused by anesthesia. / Bakgrund: Barn som opereras löper stor risk att drabbas av anestesiinducerad hypotermi. Anestesiinducerad hypotermi kan leda till allvarliga konsekvenser både peri- och postoperativt för barnet.  Med ökad förståelse, kunskap och rätt metoder kan anestesiinducerad hypotermi reduceras och öka förutsättningar till en säker vård. Syfte: Att beskriva förekomsten av hypotermi vid rutinbarnanestesi. Ett annat syfte är att studera hur anestesisjuksköterskans olika värmebevarande omvårdnadsåtgärder associeras med uppkomsten av hypotermi. Metodbeskrivning: En deskriptiv retrospektiv journalgranskningsstudie genomfördes och 147 journaler granskades. Resultat: Studiens resultat påvisade att anestesiinducerad hypotermi förekom under operationsperioden även om värmebevarande åtgärder användes. Kön, ålder och typ av operation var inte associerade med förekomst av hypotermi. Operationstiden visade sig ha en svag negativ korrelation med förekomsten av hypotermi. Värmebevarande omvårdnadsåtgärder hade ingen signifikant association med hypotermi. Slutsats: Anestesisjuksköterskan använde olika kombinationer av värmebevarande åtgärder för att minska risken för utveckling av hypotermi hos patienterna. Majoriteten av barnen erhöll tre eller fler värmebevarande åtgärder. Trots det hade flera barn hypotermi under operationen. Att försöka öka kunskapen och medvetenheten hos anestesisjuksköterskan om anestesiinducerad hypotermi, dess risker och konsekvenser samt förebyggande åtgärder kan om möjligt leda till ökade förutsättningar för en säker vård och minskat antal patientfall där oavsiktlig hypotermi förekommer. Fortsatta liknande studier inom forskningen skulle möjligt kunna leda till mer personcentrerad vård med individanpassade riktlinjer, metoder, handlingsplaner gällande anestesiinducerad hypotermi.
199

Effect of temperature on the interactions between beet cyst nematodes (Heterodera schachtii and Heterodera betae) and sugar beet

Vandenbossche, Bart 11 May 2016 (has links)
No description available.
200

The role of herbivores in mediating responses of tundra ecosystems to climate change

Kaarlejärvi, Elina January 2014 (has links)
The Arctic areas are warming more rapidly than other parts of the world. Increasing temperatures are predicted to result in shrubification, higher productivity, declining species diversity and new species invasions to the tundra. Changes in species diversity and plant community composition are likely to alter ecosystem functions with potential consequences for human population also at lower latitudes. Thus, in order to better predict the effects of the rapid arctic warming, we need knowledge on how plant communities respond to a warmer climate. Here, I investigate the effects of climate warming on tundra plant communities and focus on the role of mammalian herbivores in mediating these responses. I examined the role of herbivores by incorporating herbivore manipulations to short- and long-term warming experiments as well as along altitudinal gradients. I measured how individual plants and plant communities respond to warming with and without herbivores. Results of my PhD Thesis illustrate several ways how herbivores modify the responses of plants to warming. I found that herbivores (reindeer, hare, voles, lemmings) may prevent lowland forbs from invading open tundra.  Herbivores might also protect small tundra forbs from being outcompeted by taller and denser vegetation under climate warming. Thus, different herbivore pressures may lead to differing plant abundances and distribution shifts in different areas. Furthermore, my results show that high herbivore pressure can reverse the effects of long-term climate warming very rapidly, even in one year. This finding suggests that well-planned targeted reindeer grazing episodes could potentially be used as a conservation tool to keep selected tundra habitats open. Sudden cessation of grazing may initiate rapid changes in plant community, especially if it coincides with warm temperatures. Taken together, I show that herbivores counteract the effects of climate warming by slowing down or preventing vegetation changes in tundra. Therefore, it is important to consider mammalian herbivores when predicting tundra plant community responses to changing climate.

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