Compound distribution models for athletics records
- Authors: Hanly, Erin
- Date: 2013
- Subjects: Athletics , Statistics -- Sports , Forecasting -- Sports
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10105 , http://hdl.handle.net/10948/d1018609
- Description: World records in athletics capture the attention of both the general public and the academic community. Athletics records provide a wealth of quantifiable data, which represent the pinnacle of human ability at the time of the record. This research discusses modelling the progression of athletics world records using a compound distribution model which is found in actuarial statistics. Compound distributions allow for the simultaneous modelling of the frequency of record breaking and of the amount by which the record is improved at each record-breaking performance. A number of assumptions accompany the use of the compound distribution model. This research evaluates the athletics data for adherence to these assumptions, before carrying out distribution-fitting and goodnessof-fit testing. Forecasts of future performance are obtained by means of a simulation method. The forecasts obtained from the compound model are compared to forecasts obtained from non-linear models which have been proposed in literature. This research focuses on short-term forecasts, however, a modification to the compound model which allows for longer-term forecasts is also illustrated.
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- Date Issued: 2013
Uptake of liposomes into bacterial cells
- Authors: Oidu, Benjamin
- Date: 2013
- Subjects: Liposomes , Drug carriers (Pharmacy)
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10165 , http://hdl.handle.net/10948/d1021010
- Description: Liposomes are small phospholipid vesicles that have been widely investigated as drug carriers for the delivery of therapeutic agents. A variety of liposome formulations are presently under clinical trial exploration, while others have already been approved for clinical use. The aim of this study was to optimize liposome uptake into bacterial cells. Both gram-positive and gram-negative bacteria were used in the study as well as Candida albicans.Response surface methodology (RSM) using a central composite design (CCD) model was used to optimize liposomal formulations of carboxyfluorescien (CF) for each of the three microbes, and also the three microbes in combination namely; Staphylococcus aureus (Sa), Escherichia coli (Ec) and Candida albicans (Ca). Percentage of CF encapsulated and CF increase in Uptake were investigated with respect to two independent variables that were, cholesterol (CHOL) and stearylamine (SA) content. Design Expert 8 was used for the purpose of finding the combination of independent variables that would yield an optimal formulation for each microbe and the three microbes in combination. The model selected by the software managed to reasonably correlate the predicted models to the experimental data. Encapsulation of carboxyfluorescien (CF) into a liposome formulation enhanced its uptake by Staphylococcus aureus and Escherichia coli as well as Candida albicans. This was evident in the increase in CF uptake when the uptake rate of free CF was compared with that of liposomal CF.
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- Date Issued: 2013