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Dichloro-diphenyl-trichlorethane (DDT) is a chemical used in malaria control through indoor residual spraying (IRS) and has saved numerous lives in the past six decades. DDT use is restricted/banned under the Stockholm Convention on Persistent Organic Pollutants. Passive air sampling using polyurethane foam was conducted in South Africa to evaluate the presence and trends of DDT and its metabolites. Three sampling sites were used, namely, Barberspan Nature Reserve (rural agricultural), Vanderbijlpark (urban industrial) and Molopo Nature Reserve (isolated nature reserve). Sampling was conducted for a period of one year in 2008. Back trajectories from the three sampling sites were generated using HYSPILT to determine the sources of DDT metabolites to the sampling areas. Forward trajectories were also generated to determine the movement, distribution, and fate of DDT from the areas under Indoor residual spray of DDT for malaria control in South Africa and Swaziland. Chemical analysis was conducted by the RECETOX (Mazaryk University) in the Czech Republic. DDT metabolites (o,p’-DDE, p’p’-DDE, o.p’-DDD, p,p’-DDD, o,p’-DDT p,p’-DDT) were analysed using a GC-ECD (HP 5890). Vanderbijlpark had the highest concentrations of DDT metabolites throughout the year. Barberspan had the second highest concentration and Molopo the least. Seasonal changes in concentration were much the same at the three sites. %p,p’-DDT of ΣDDT is consistent with IRS spraying months in South Africa and Swaziland. A combinations of backward and forward trajectories, together with the temporal pattern of change of the %p,p’-DDT of ΣDDT support the deduction that DDT sampled from the three study sites (to some degree) came from IRS areas in South Africa and Swaziland. The presence of DDT in Molopo Nature Reserve and Barberspan is evidence of long-range transportation over dry semi-desert areas. Back-trajectories indicate the possible source of DDT were the IRS areas in the provinces of Limpopo, Mpumalanga, and KwaZulu-Natal. Some air masses to the sampling sites came from the sprayed areas. The forward trajectories also revealed that the DDT sprayed during IRS could undergo LRT. The DDT metabolites were able to travel to neighbouring countries such as Mozambique, Namibia, Zimbabwe and Botswana. / MSc (Environmental Sciences), North-West University, Potchefstroom Campus, 2013

Dichloro-diphenyl-trichlorethane (DDT) is a chemical used in malaria control through indoor residual spraying (IRS) and has saved numerous lives in the past six decades. DDT use is restricted/banned under the Stockholm Convention on Persistent Organic Pollutants. Passive air sampling using polyurethane foam was conducted in South Africa to evaluate the presence and trends of DDT and its metabolites. Three sampling sites were used, namely, Barberspan Nature Reserve (rural agricultural), Vanderbijlpark (urban industrial) and Molopo Nature Reserve (isolated nature reserve). Sampling was conducted for a period of one year in 2008. Back trajectories from the three sampling sites were generated using HYSPILT to determine the sources of DDT metabolites to the sampling areas. Forward trajectories were also generated to determine the movement, distribution, and fate of DDT from the areas under Indoor residual spray of DDT for malaria control in South Africa and Swaziland. Chemical analysis was conducted by the RECETOX (Mazaryk University) in the Czech Republic. DDT metabolites (o,p’-DDE, p’p’-DDE, o.p’-DDD, p,p’-DDD, o,p’-DDT p,p’-DDT) were analysed using a GC-ECD (HP 5890). Vanderbijlpark had the highest concentrations of DDT metabolites throughout the year. Barberspan had the second highest concentration and Molopo the least. Seasonal changes in concentration were much the same at the three sites. %p,p’-DDT of ΣDDT is consistent with IRS spraying months in South Africa and Swaziland. A combinations of backward and forward trajectories, together with the temporal pattern of change of the %p,p’-DDT of ΣDDT support the deduction that DDT sampled from the three study sites (to some degree) came from IRS areas in South Africa and Swaziland. The presence of DDT in Molopo Nature Reserve and Barberspan is evidence of long-range transportation over dry semi-desert areas. Back-trajectories indicate the possible source of DDT were the IRS areas in the provinces of Limpopo, Mpumalanga, and KwaZulu-Natal. Some air masses to the sampling sites came from the sprayed areas. The forward trajectories also revealed that the DDT sprayed during IRS could undergo LRT. The DDT metabolites were able to travel to neighbouring countries such as Mozambique, Namibia, Zimbabwe and Botswana. / MSc (Environmental Sciences), North-West University, Potchefstroom Campus, 2013

Wind is a fluctuating source of energy and, therefore, it can cause several technical impacts. These can be tackled by forecasting wind speed and thus wind power. The introduction of several statistical models in this field of research has brought to light promising results for improving wind speed predictions. However, there is not converging evidence on which is the optimal method. Over the last three decades, significant research has been carried out in the field of short-term forecasting using statistical models though less work focuses on longer timescales. The first part of this work concentrated on long-term wind speed variability over the UK. Two subsets have been used for assessing the variability of wind speed in the UK on both temporal and spatial coverage over a period representative of the expected lifespan of a wind farm. Two wind indices are presented with a calculated standard deviation of 4% . This value reveals that such changes in the average UK wind power capacity factor is equal to 7%. A parallel line of the research reported herein aimed to develop a novel statistical forecasting model for generating monthly mean wind speed predictions. It utilised long-term historic wind speed records from surface stations as well as reanalysis data. The methodology employed a SARIMAX model that incorporated monthly autocorrelation of wind speed and seasonality, and also included exogenous inputs. Four different cases were examined, each of which incorporated different independent variables. The results disclosed a strong association between the independent variables and wind speed showing correlations up to 0.72. Depending on each case, this relationship occurred from 4- up to 12-month lags. The inter comparison revealed an improvement in the forecasting accuracy of the proposed model compared to a similar model that did not take into account exogenous variables. This finding demonstrates the indisputable potential of using a SARIMAX for long-term wind speed forecasting.

International Telemetering Conference Proceedings / October 21, 2002 / Town & Country Hotel and Conference Center, San Diego, California / For the past thirty years, many people around the world have been engaged in studies to determine how long tape will last. We have learned how to extend the life of tapes but no one has come up with a method for predicting the life of a tape. This paper will summarize the present-day recommended practices for tape care and storage and will also describe the most common tape problems and how to overcome them. The most common problem with playing an old tape is finding a machine to play it. Machine obsolescence is probably a bigger problem than tape degradation.

Macrodiversity system is a communication architecture where base stations (BS) act as distributed nodes of a multiple-input multiple-output (MIMO) antennas. It has many promising features that can improve system performance from a network perspective, such as improving the weak signals of users affected by shadow fading, or users at the cell-edge. They also allow multiple users to share the same resource in time and frequency, improving the overall user capacity. Traditionally, evaluating the link quality of resource-sharing users requires instantaneous channel state information (CSI). However, finding compatible users to share resource in macrodiversity systems is a challenging task. For macrodiversity systems, instantaneous CSI could be passed to the backhaul processing unit (BPU) through the network backhaul. This creates a delay in the signal, and makes instantaneous CSI a less accurate reflection of the channel environment at the time. Passing instantaneous CSI of all users also creates a significant amount of network overheads, reducing the overall efficiency of the network. Compared to MIMO systems with co-located antennas, macrodiversity systems cover a larger geographical area and more users. For this reason, the number of user selection combinations can become extremely large, making scheduling decisions in real time an even more challenging task. These problems limit the realisation of the user capacity potential of macrodiversity systems. This thesis presents a low complexity method of resource allocation for up-link macrodiversity systems. In particular, it uses long-term power to estimate the link quality of resource-sharing users. Using long-term power bypasses the issue of channel estimation error introduced by the network delay, and it also reduces the communication overhead on the network backhaul. In this thesis, we use Symbol-Error Rate (SER) as the measure for link quality. Using the method developed by Basnayaka [1], we are able to estimate SER of resource-sharing users using long-term power. Using the SER estimation method, we further proposed a user compatibility check (UCC), which evaluates the compatibility of users sharing the same resource. Users are only considered compatible with each other if all of them meet a pre-defined SER threshold. We attempt to reduce the complexity of user selection by using heuristic solution-finding methods. In our research, we found that greedy algorithms have the least complexity. We propose four low-complexity user selection algorithms based on a greedy algorithm. These algorithms are simulated under different environment parameters. We evaluate the system performance in terms of utilisation and complexity. Utilisation refers to the percentage of allocated users compared to the theoretical user capacity. Complexity refers to the number of SER calculations required to find a resource allocation solution. From the simulation results, we observed that with the proposed user selection algorithms, we can achieve moderately high utilisation with much lower complexity, compared to finding user selections via an exhaustive search method. Out of the proposed user selection algorithms, the Priority Order with Sequential Removal (PO+SR) and the First-Fit (FF) algorithm have the best overall performance, in terms of the trade-off between utilisation performance, and complexity performance. The final choice of the algorithm will depend on the processing power and the system performance requirement of the macrodiversity system.

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This communication study investigated characteristics of evidence that influenced memory and beliefs about juvenile delinquency across multiple time periods. Four hypotheses were proposed: (H1) vivid evidence is more memorable than nonvivid evidence, (H2) story evidence is more memorable than statistical evidence, (H3) vivid evidence is more persuasive than nonvivid evidence after 48 hours, but not after one week, and (H4) story evidence is more persuasive than statistical evidence after 1 week, but not after 48 hours. A 2 x 2 x 3 factorial design with an offset control was employed, using evidence (story or statistical), vividness (vivid or nonvivid), and time (immediate, or 48 hour delay, or 1 week delay) as independent variables, and recognition memory and judgment of belief as dependent variables. Four written messages, reflecting a complete crossing of evidence and vividness, were used as different types of evidence to attempt to persuade beliefs. A total of 280 undergraduate college students participated in the experiment. Hypotheses 1 and 2 were supported by main effects for vividness and evidence, and by a significant ordinal two-way interaction between vividness and evidence such that vivid story was the most memorable form of evidence. The two-way interactions used to test Hypotheses 3 and 4 were nonsignificant. A main effect for evidence related to Hypothesis 4 indicated that statistical evidence was more persuasive than story evidence at the delayed time periods. Thus, Hypotheses 3 and 4 were not supported. Alternative explanations were discussed to account for the persuasiveness of statistical evidence and the lack of persuasiveness of story evidence at the delayed time periods. Limitations of the study were noted, such as the small amount of experimental variance accounted for in some of the findings, and the limited generalizability of the findings. Finally, several suggestions for future research, including reconceptualizing evidence as a multidimensional construct, were presented.

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No description available.