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The core of stock portfolio diversification is to pick stocks from different correlation clusters when forming portfolios. The result is that the chosen stocks will be only weakly correlated with each other. However, since correlation matrices are high dimensional, it is close to impossible to determine correlation clusters by simply looking at a correlation matrix. It is therefore common to regard industry groups as correlation clusters. In this thesis, we used three visualization methods namely Hierarchical Cluster Trees, Minimum Spanning Trees and neighbor-Net splits graphs to “collapse” correlation matrices’ high dimensional structures onto two-dimensional planes, and then assign stocks into different clusters to create the correlation clusters. We then simulated sets of portfolios where each set contains 1000 portfolios, and stocks in each of the portfolio were picked from the correlation clusters suggested by each of the three visualization methods and industry groups (another way of determine correlation clusters). The mean and variance distribution of each set of 1000 simulated portfolios gives us an indication of how well those clusters were determined. The examinations were conducted on two sets of financial data. The first one is the 30 stocks in the Dow Jones Industrial average which contains relatively small number of stocks and the second one is the ASX 200 which contains relatively larger number of stocks. We found none of the methods studied consistently defined correlation clusters more efficiently than others in out-of-sample testing. The thesis does contribute the finance literature in two ways. Firstly, it introduces the neighbor-Net method as an alternative way to visualize financial data’s underlying structures. Secondly, it used a novel “visualization

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The present Bachelor thesis is written about a rock slide which took place in the southern part of Stockholm in the early 2000s. The studied area is located relatively close to a steeply-dipping fault with NW-SE orientation. The field work was carried out by four students, with me and other student focussing on the rock slide slope and two scan lines N and E of the rock slide. The geological structures, which were assumed to be responsible for the rock slide, have been studied carefully during surface mapping. The data was analysed using two rock mass classifications and stereographic projection. Additionally, a digital elevation map of the area was analysed in terms of slope angle distributions using GIS. It was shown that the orientation of discontinuities at the site coincides with the direction of the cutting work. Thus, the rock slide was unavoidable since the cutting work was carried out subparallel to the fractures main orientation.

A simple, rapid and efficient method for the extraction and purification of chlorophyll-a from plant sources has been developed. And with it, a new method for the ·extraction of chlorophyll in winter, which has been previously problematic, has been developed. The methods are summarized in flow diagrams showing the elimination of carotene and xanthophylls. The chlorophyll-a isolated has been demetallated to obtain pheophytin-a that in tum has been complexed with cobalt(II), copper(II), zinc, nickel(II) and chromium(Ill) ions. The resulting metal pheophytin complexes, chlorophyll-a and pheophytin-a have been fully characterized by ultraviolet-visible and Fourier transform infrared spectroscopies, electrospray ion mass spectrometry and elemental analysis. For the first time, the kinetics of the oxidation of cobalt(II) pheophytin-a by chromium(III) has been followed spectrophotometrically at temperatures ranging from 313 to 333 K. The reaction has been found to be first order in the concentration of the hexaaquachromium(III) cation. The oxidation-reduction mechanism proposed for the reaction is an outer-sphere electron tunnelling mechanism. The ease of demetallation and complexation of chlorophyll-a has highlighted the problem caused by acidity and the presence of these metal ions in soils, on the chlorophyll content of leaves. / Thesis (D.Phil) North-West University, Mafikeng Campus, 2005

AIM: To evaluate the accuracy of current semi-automatic and fully automatic 2D lateral cephalometric analysis programs. MATERIALS AND METHODS: 60 lateral cephalometric radiographs were randomly selected and grouped based their skeletal malocclusions to form 3 equal groups of 20 Class I, 20 Class II and 20 Class III. These radiographs were then analyzed via traditional hand-based analysis. The values obtained from this method of analysis were compared to 4 subsequent methods of analysis. These consisted of semi-automatic analysis using Dolphin Imaging software, semi-automatic analysis using Kodak Orthodontic Imaging software, fully automatic analysis using Kodak Orthodontic Imaging software and fully automatic analysis combined with limited landmark changes using Kodak Orthodontic Imaging software. RESULTS: ICC tests were completed to compare the gold standard hand-based analysis to the 4 subsequent methods. The values obtained from semi-automatic Dolphin and Kodak Orthodontic Imaging software were found to be comparable to hand-based analysis. Whereas, the values obtained from the fully automatic mode of Kodak Orthodontic Imaging software were not found to be comparable to hand-based analysis. CONCLUSIONS: Digital cephalometric programs can be used as an accurate method when performing lateral cephalometric analyses. The fully automatic mode of these programs should only be used as a support to diagnosis and not as a diagnostic tool.

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No description available.

A method is described for the determination of N-nitrosoproline (NOPRO) in cured meat products. NOPRO was extracted with ethyl acetate from a slurry of cured meat and water after the addition of ammonium sulfamate and acid. This nitrosamino acid was converted to the methyl ester and after further purification, it was quantitated and confirmed by gas liquid chromatography and mass spectroscopy. Recoveries of 10 μg from spiked samples averaged about 70%. A capillary column was used to confirm the presence of low levels of MeNOPRO in the extracts. An oscilloscope, utilizing horizontal sweep magnification of the mass spectrometer output, was used to detect the elution of MeNOPRO from the column by monitoring the m/e 30 ion. The presence of 5 nanograms per injection of concentrated cured meat extract could be confirmed. NOPRO was detected in several commercial meat products. Five of six bacon samples analyzed were found to contain NOPRO at levels ranging from 13-46 ppb. A precooked ham slice and a sample of breakfast beef contained 22 and 62 ppb NOPRO, respectively. NOPRO was not detected in a sample of canned chopped ham nor a wiener sample. The detection of NOPRO, a non-volatile nitrosamine, in cured meats suggests that the formation of other non-volatile nitrosamines is possible. To date, only volatile nitrosamines have been analyzed and confirmed by mass spectrometry. The ubiquity of proline and the finding of NOPRO in several different cured meat products suggest that NOPRO could be an indicator of nitrosation in foods. Bacon cured in brines containing 800 and 1600 ppm nitrite contained about 50 and 100 ppm residual nitrite, respectively. Bacons receiving the lower nitrite level contained no NOPRO while the higher nitrite treated bacons contained over 100 ppb NOPRO. Frying of bacon was found to destroy 86 to 100% of NOPRO in the five samples analyzed. NOPRO has been reported to break down during heating to nitrosopyrrolidine (NOPYR). However, the levels of NOPRO determined in raw bacon were not sufficient to produce the amounts of NOPYR reported in fried bacon if the rate of conversion was similar to that previously reported in model studies. / Graduation date: 1974

Graduation date: 1973