Objetivo. Delinear sistema de classificação baseado na distribuição brasileira do Índice de Massa Corporal (IMC) para avaliação do estado nutricional de crianças e adolescentes brasileiros. Método. Foram utilizados o método LMS para o cálculo dos parâmetros da curva do IMC e a função polinomial para modelá-los ao longo das idades. A distribuição saudável do IMC foi delineada a partir dos indivíduos de 2 a 19 anos da Pesquisa Nacional Nutrição e Saúde, realizada em 1989. Os valores críticos para classificação do estado nutricional foram expressos segundo centis ou equivalentes aos valores de IMC 17,5; 25 e 30 kg/m2 no início da idade adulta. A curva brasileira foi calibrada contra a população de referência e comparada outras curvas de referência estrangeiras. Finalmente, a curva brasileira foi empregada para descrever a mudança secular no grupo estudado ao longo de três décadas. Resultados. Os resultados foram apresentados na forma de cinco artigos. No primeiro foram descritos, em intervalos semestrais, os parâmetros L, M e S da curva brasileira e os valores críticos dos centis tradicionalmente empregados e aqueles adulto-equivalentes. No segundo, os parâmetros L, M e S gerados foram comparados à população original. No terceiro, a curva nacional foi comparada, em seus fundamentos, a curvas estrangeiras. No quarto, verificou-se o impacto clínico decorrente do emprego da curva nacional ou das curvas estrangeiras à população brasileira. No quinto, foi descrita a mudança secular da distribuição do IMC e da classificação do estado nutricional de crianças e adolescentes brasileiros ao longo de três décadas. / Objetive. Drawing the Brazilian reference curve Body Mass lndex (BMI) to evaluate the nutritional status from Brazilian children and adolescents. Method. It were used the LMS method to calculate the BMI curve parameters and the polynomial function to model the parameters across age. The BMI healthy distribution was taken from data of individuais from 2 to 19 years of the Pesquisa Nacional Saúde e Nutrição, carried out in 1989. The BMI cutoff values to classify nutritional status were realized as percentiles and as BMI adult-equivalent values to 17.5, 25 and 30 kg/m2 at earty adult age. The Brazilian curve was calibrated against the reference population and compared to others foreign reference curves. Finally, the Brazilian curve was used to describe the secular change of the studied group across three decades. Results. The results were realized in five papers. The first one presents the L, M and S parameters and the BMI cutoffs as percentiles and as adult-equivalents values. At the second, the I, M and S parameters were calibrated according to the source reference population. At the third one, the Brazilian curve was compared, using the basics, to foreign curves. At the fourth, the clinical consequences from employment of the Brazilian and foreign curves to the Brazilian population were measured. At the fifth, the secular changes in BMI distribution and at the nutritional status from Brazilian children and adolescents were described through three decades.

A complexidade de compreensão durante a observação realizada a partir da identificação de um possível quadro de evolução em um sistema climático marcado por uma série temporal longa de uma determinada variável ambiental deve-se ao fato do ambiente sofrer múltiplas interações físico-químicas que naturalmente ocorrem nas escalas global, regional e local. Na intenção de compreender alguns elementos dessa dinâmica foram analisadas algumas hipóteses que podem nos aproximar de possíveis explicações a respeito do contexto que emerge a partir da realidade observada. Neste contexto foi analisada a hipótese de que o ambiente fisicamente alterado pelo homem possa estar influenciado no número de episódios de chuvas nas suas diversas intensidades durante o intervalo de uma hora. A segunda hipótese analisou a possibilidade das alterações em grandes escalas envolvendo às flutuações de temperatura observadas na superfície do mar (TSM) de uma região específica (Niño3.4) localizada no pacífico equatorial possam estar influenciando e/ou intensificando os episódios de chuva em escala local. No entanto, a partir dessas possibilidades o objetivo foi a de analisar através do uso de métodos estatísticos, a partir da aplicação de ajustes e correlações lineares, a identificação de tendências positivas ou negativas, no quadro de cada tipo de chuva e, posteriormente, no quadro das variações de TSM, da região Niño3.4. O segundo procedimento adotado avaliou de uma maneira qualitativa a possibilidade de haver correlações positivas entre os dois ajustes lineares analisados. Os resultados indicaram que a variabilidade climática anual da região Niño3.4 durante a série completa (1970-2009) apresentou um quadro de aquecimento (ajuste positivo). Por outro lado, também foi observado o aquecimento da TSM durante séries específicas da série completa identificadas como fase Neutra, ENOS e La Niña. No entanto, a série especifica relativa à fase El Niño apresentou um comportamento inverso, no caso, um resfriamento na TSM durante o período analisado. Neste caso, foi constatado que o aquecimento anual da TSM da região Niño3.4 ocorre em função do aquecimento observado durante as anomalias negativas (La Niña). O quadro dos ajustes lineares de cada tipo de chuva revelou uma diminuição horária na frequência de chuvas muito fracas (nevoeiros e neblinas), de chuvas fracas (chuviscos e garoas) e de chuvas moderadas (tempestades leves oriundas de nimbostratus). Por outro lado, o quadro de ajustes lineares para chuvas mais intensas foram positivas, como no caso, de chuvas fortes (tempestades ordinárias) e muito fortes (tempestades severas). / The complexity of understanding during the observation carried out from the identification of a possible behavior of evolution in a climatic system marked by a series storm long of a determined environmental variable is due to the fact of the environment suffer multiple interactions chemical-physically what naturally take place in the global, regional and local scales. In the intention of understanding some elements of this dynamic one there were analyzed some hypotheses that can bring near us of possible explanations as to the context that surfaces from the observed reality. In this context it was analyzed the hypothesis of which the environment physically altered by the man could be influenced the number of episodes of rains in his several intensities during the interval of an hour. The second hypothesis analyzed the possibility of the alterations in great scales wrapping to the fluctuations of temperature observed in the surface of the sea (TSM) of a specific region (Niño3.4) located in the Pacific Ocean be able to be influencing and / or intensifying the episodes of rain in local scale. However, from these means the objective was it of analyzing through the use of statistical methods, from the application of agreements and linear correlations, the identification of positive or negative tendencies, in the picture of each type of rain and, subsequently, in the picture of the variations of TSM, of the region Niño3.4. The second adopted proceeding valued in a qualitative way the possibility to be positive correlations between two linear analyzed agreements. The results indicated that the climatic annual variability of the region Niño3.4 during the complete series (1970-2009) presented a picture of heating (positive agreement). On the other side, also the heating of the TSM was observed during specific series, of the complete series, identified like phases Neuter, ENOS and La Niña. However, the series specify relative to the phase El Niño he presented a reverse behavior, in the case, a cooling in the TSM during the analyzed period. In this case, it was noted that the annual heating of the TSM of the region Niño3.4 takes place in function of the heating observed during the negative anomalies (La Niña). The picture of the linear agreements of each type of rain revealed a reduction hourly in the frequency of very weak rains (thick fogs and fogs), of weak rains (drizzles and drizzles) and of moderate rains (light originating storms of nimbostratus). On the other side, the picture of linear agreements for more intense rains they were positive, since in the case, of strong rains (ordinary storms) and very strong (severe storms).

Machine learning (ML) has become one of the most powerful classes of tools for artificial intelligence, personalized web services and data science problems across fields. Within the field of machine learning itself, there had been quite a number of paradigm shifts caused by the explosion of data size, computing power, modeling tools, and the new ways people collect, share, and make use of data sets. Data privacy, for instance, was much less of a problem before the availability of personal information online that could be used to identify users in anonymized data sets. Images, videos, as well as observations generated over a social networks, often have highly localized structures, that cannot be captured by standard nonparametric models. Moreover, the “common task framework” that is adopted by many sub- disciplines of AI has made it possible for many people to collaboratively and repeated work on the same data set, leading to implicit overfitting on public benchmarks. In addition, data collected in many internet services, e.g., web search and targeted ads, are not iid, but rather feedbacks specific to the deployed algorithm. This thesis presents technical contributions under a number of new mathematical frameworks that are designed to partially address these new paradigms. • Firstly, we consider the problem of statistical learning with privacy constraints. Under Vapnik’s general learning setting and the formalism of differential privacy (DP), we establish simple conditions that characterizes the private learnability, which reveals a mixture of positive and negative insight. We then identify generic methods that reuses existing randomness to effectively solve private learning in practice; and discuss weaker notions of privacy that allows for more favorable privacy-utility tradeoff. • Secondly, we develop a few generalizations of trend filtering, a locally-adaptive nonparametric regression technique that is minimax in 1D, to the multivariate setting and to graphs. We also study specific instances of the problems, e.g., total variation denoising on d-dimensional grids more closely and the results reveal interesting statistical computational trade-offs. • Thirdly, we investigate two problems in sequential interactive learning: a) off- policy evaluation in contextual bandits, that aims to use data collected from one algorithm to evaluate the performance of a different algorithm; b) the problem of adaptive data analysis, that uses randomization to prevent adversarial data analysts from a form of “p-hacking” through multiple steps of sequential data access. In the above problems, we will provide not only performance guarantees of algorithms but also certain notions of optimality. Whenever applicable, careful empirical studies on synthetic and real data are also included.

In this thesis I am going to investigate the trends within e-business, what it is that drive these trends and why these drivers are of such importance. I chose this subject since I have found it very interesting and useful in my career because of the importance it embraces in today’s business world. The aspect of e-commerce has changed a lot lately to in the beginning of the 1990s be about being present on the Internet with a web site, to being about transactions, meaning to buy or sell through digital media at the end of the 1990s, to today be about being used to make profitability – an era that can be called e-business, because it is now that e-business finally gets its big breakthrough and starts to be recognized as a necessity for companies to survive. As long as e-business has existed so have trends in the same matter. What will be the trends of e-business in the future? Impossible to say of course, but by taking today’s major trends into consideration, and to look at what drives these trends might have, will make it possible to get a glimpse of the future of this relatively new business phenomenon called e-business. To get the best result possible of my thesis I have made a wide literature study in the subject by reading and examine accurate literature and articles as well as carried out interviews with different IT-gurus and other persons that is thought to withhold a lot of information about my chosen subject. I have focused on two major trends being customer oriented trends and service digitization. Customer oriented trends are trends which have their focus towards customers such as customer service, offering more product choices and to have integrated solutions. Service digitization is the transformation of paper-based transactions into the new integrated multi-channel processes. The driver I have found of most significance and therefore focused on is customers. Customers are important as drivers since they have adopted a new role in the business process. Customers nowadays have found a way to let their voices to be heard. With the help of blogs, social networks and wikis over the Internet they can express their feelings and suggestions about products as well as companies and have so to say gained a more active role as customers to also taking part of the development. This voice of the customers is highly essential to listen to if you as a company want to survive in a business world where customers get more and more power. After finishing this study I came up with the importance of service, and especially customer service as well of personalization and customization (to personalize the shopping experience for the customer). Another important conclusion is the importance of customers, both as trends to focus on, as well as drivers behind these trends. ii Acknowledgements

Magister Public Health - MPH / Background: The factors that underlie teenage pregnancies are complex and multifactorial. The prevailing perception is that teenage pregnancies are increasing in South Africa. However, the empirical extent and trends in teenage births in the Western Cape Province are not well understood. A systematic analysis of routine health information for the data element.Delivery in facility to women under 18 years for the period 1 April 2000 to 31 March 2012 is presented in order to contribute to documenting and understanding how this problem manifests in the Western Cape Province.Objectives:The objectives of the study were to describe the trends in the number of deliveries for women under the age of 18 years in the Western Cape Province for the period 1 April 2000 until 31 March 2012, and to compare the trends within and between districts. A secondary aim was to explore the quality and usefulness of Routine Health Information in the Western Cape Province focusing on the dataset for deliveries for women under the age of 18 years.Methods:The data for the Province extracted from the Sinjani system (the data repository for health information management in the Western Cape Department of Health) was subjected to a trend analysis at the Provincial, District and Sub-District level. The absolute numbers of all deliveries, and deliveries for women under the age of 18 years as well as proportions of deliveries for women under the age of 18 years were compared across districts, years and seasons. Results were discussed with senior managers in the Department of Health as compared to performance indicators presented in workshop settings to triangulate and help interpret findings.Findings The key finding is that both the absolute number of deliveries for women under the age of 18 years and the deliveries for women under the age of 18 years relative to all deliveries have declined steadily since 2007, while 8 absolute numbers of deliveries in 2012 were only slightly higher than in 2000-2001, despite an increase of 19.4% in the total population of the Province between 2002 and 2011. Despite the decline in the number of deliveries for women under the age of 18 years, the number of deliveries remains high. Seasonal increases in numbers of deliveries coincide with school holidays in most districts. The data analysis also revealed challenges with the quality of the data, and that it is not possible to determine the age distribution of deliveries across women under 18 years from the provincial data set. Routinely collected data do not permit analysis or comparison of births at the ward level where significant socio-economic variations are likely to influence fertility.Conclusions and Recommendations:The data did not support widespread perceptions of rapidly increasing teen births. The declining birth rates and relatively stable proportion of under 18 births relative to all births suggest that adding new indicators throughout the entire routine information system is not justified on public health or economic grounds. However, more detailed and disaggregated evidence is needed to inform locally tailored interventions and could be obtained from alternate sources of information such as point prevalence surveys, annual surveys, or data collection at sentinel sites. While teenage birth rates are not increasing, they remain high. It is recommended that additional service delivery models be explored to ensure that sexual reproductive health services are strengthened and delivered in a manner that would be acceptable to young people. Further, it is recommended that programmatic interventions that target the sexual reproductive health choices made by young people be scaled up in partnership with intersectoral partners and communities in order to mitigate against seasonal increases in the number of deliveries for women under 18 years of age.

This study investigates the underlying rationale of environmentally and socially conscious young Swedish consumers for their continued consumption of fast fashion. Furthermore this study assesses influential factors that shape young Swedish consumers’ attitudes and beliefs towards fast fashion. The fast fashion business model is largely based on the exploitation of poor working conditions and lack of environmental protection laws in the production countries. However, consumers are becoming increasingly aware of this dark side of fast fashion and the retailers are addressing their concerns with selective organic clothing collections. In order to gain in debt understanding of young Swedish consumers rationalizations, I applied an inductive research approach based on the philosophy of interpretive social science. More specifically I conducted semi-structured interviews with 12 Swedish participants between the ages of 18 and 25. The findings of this study show that the participants prioritize price, quality and how the clothes look over where they have been produced and under what circumstances. Furthermore, the interviewees indicate a high dependency on the Swedish government to punish misconducts of fast fashion retailers. Greenwashing, the Swedish school system as well as a green trend in contemporary Swedish society seem to shape young consumers attitudes and beliefs towards fast fashion. Future research could investigate how the Swedish government and the Swedish school system can take a more pro-active role in educating their citizens and students about the actual negative impacts caused by the overconsumption of fast and disposable fashion towards society and environment.

The Intertropical Convergence Zone (ITCZ) is a feature that results from the ocean-atmosphere interactions in the tropics around the world. The ITCZ is characterized by surface wind convergence, tall storm clouds, and it forms a belt of high time-averaged precipitation around the globe. The ITCZ undergoes seasonal migrations between 5°S and 15°N roughly following the subsolar point on Earth with the seasons, with a mean annual position located slightly above the Equator, between 2° and 5°N. This study tested the hypothesis that there was a northward shift in the median position of the ITCZ in the first decade of the 2000’s relative to the 1900’s. This hypothesis has been posed in the literature given a weakening in the intensity of the Trade Winds observed in the southern Caribbean Sea during the first decade of the 2000’s, with concomitant ecological impacts due to weakening in coastal wind-driven upwelling. The hypothesis was tested by analyzing variations in the monthly latitudinal position of the ITCZ over the Atlantic Ocean relative to the median position computed for the period 1987-2011. The position of the ITCZ was derived from satellite-derived ocean surface wind measurements collected from 1987 to 2011. A Mann-Kendall analysis and a Monte Carlo simulation were used to test for trends in the median cross-basin latitudinal position of the ITCZ. The study included an analysis of regional changes across the tropical central Atlantic (50°W to 15°W), the Western Atlantic (50°W to 30°W), and the Eastern Atlantic (30°W to 15°W) within the tropics. The results show a slight southward trend in the median position of the ITCZ over the central Atlantic and also in the Eastern Atlantic in the first decade of the 2000’s relative to the 1990’s. While this trend is barely significant, it is likely simply due to interannual variation in the average annual position of the ITCZ. The data were also examined for the timing and persistence of a double ITCZ in the Atlantic. The double ITCZ over the Atlantic appeared every year in February or March, with the largest separation between the northern and southern branches of the ITCZ observed in June and July. The possible effects of changes in the average latitudinal position of the ITCZ on the upwelling in the Cariaco Basin (southeastern Caribbean Sea off Venezuela) were also examined. Anomalies of the median of the latitudinal position of the ITCZ in the Atlantic were compared with anomalies of in-situ temperature collected during the 1990’s and the first decade of the 2000’s by the CARIACO Ocean Time-Series program and with anomalies of satellite SST (from the Advanced Very High Resolution Radiometer satellite; AVHRR) from 1995 to 2016. Correlation analysis were performed between anomalies of water temperatures at various depths and anomalies of satellite SST with anomalies of the monthly mean ITCZ position with lags up to 3 months for the time series, and also just for the Cariaco basin upwelling months (December-April). For the whole Cariaco time series there were no significant correlations between the anomalies of the ITCZ position and anomalies in subsurface temperatures in the Cariaco Basin. However, during the upwelling period, the central Atlantic and Western Atlantic ITCZ position anomalies were directly correlated with Cariaco Basin temperature anomalies with no-lag (r = 0.20), and the central and Eastern Atlantic ITCZ position anomalies were inversely correlated with Cariaco Basin temperatures (r ~ -0.22 to -0.28) with ITCZ leading Cariaco temperatures by 3 months. However, these correlations were low, indicating that other factors than the position of ITCZ latitudinal position play bigger role on the Cariaco basin upwelling variability. Interannual variability in oceanographic and meteorological characteristics of the Atlantic Ocean are expected as a result of large-scale changes in other regions of the world, including due to changes such as the El Niño Southern Oscillation (ENSO) and the Atlantic Multidecadal Oscillation (AMO). Six oceanic-atmospheric variables are used to monitor ENSO over the tropical Pacific, while the AMO is determined by monitoring SST over the Atlantic. Correlations with lags of up to ± 6 months were conducted with those climate indices and the anomalies of the median monthly latitudinal position of the ITCZ. Significant direct correlations with ENSO (Multivariate ENSO Index) were seen in the Atlantic and Western Atlantic (r = 0.15), with ENSO leading the position of the ITCZ anomalies by 3 months. This implies that within three months after an El Niño event (warm ENSO anomaly in the Pacific) the ITCZ over the mid-Atlantic and Western Atlantic Ocean tends to shift to a more northerly position. The AMO also had a direct influence on the anomalies of the ITCZ position (r = 0.13) in the Central and the Western Atlantic, with the AMO leading ITCZ anomalies by 1 month (i.e. a warming of the North Atlantic led to a northward shift in the ITCZ one month later). Correlations between AMO and the ITCZ anomalies in the Eastern Atlantic were also direct but with no lag. Although significant, these correlations were low. An inverse correlation (~ -0.35) was found between ENSO and anomalies of water temperature of the Cariaco Basin. ENSO lagged ocean temperature anomalies by 3 to 4 months for both the whole Cariaco time series and for the upwelling months of CARIACO data. Correlations with AMO were direct (~ 0.4); for the whole time series AMO led Cariaco temperature anomalies by 3 months, but for the upwelling months AMO lagged Cariaco temperature anomalies by one month.

Cholera made an unforeseen appearance on the eastern coast of South Africa in the province of KwaZulu-Natal (KZN) in August 2000. Having started from the more urban centres of the coastal region of the province, cholera proceeded unabated to the interior of the province where no community was spared from the scourge. Despite prompt medical intervention, health education and media awareness campaigns, cholera continued to spread throughout KZN. By March 2004, the official statistics of cholera cases in KZN as per the Cholera Database records, stood at 158 895 cases (Dept-KZN Health, 2000). The death toll as reported in the Cholera Database was 575 persons that translated to a percentage case fatality rate of 0.36%; the lowest when compared to the previous epidemics recorded in South African (Kustner et al., 1981; Küstner and du Plessis, G. 1991). An interesting feature of the epidemic was that 99% of the cases recorded by the central and provincial Departments of Health during the height of the epidemic were all from KZN. The question then was, what factors played a role in the cholera epidemic of KZN? This study sought to understand the outbreak and the factors that possibly contributed to the spread of the 2000-2004 cholera epidemic in KZN. The drivers of disease associated with the communities affected by cholera were also explored by analysing the complex and dynamic interaction of their biological, socio economic, and environmental nature over time and space. The nature of the study was such that it called for a multi faceted design to involve not just understanding the societal aspect of the disease but its demographic, ecological and spatial characteristics as well. Thus GIS was used as a research tool to facilitate the comparison of the disease trends and risk factors on a spatial level in order to determine the possible role(s) played by the different environmental and socio-economic drivers. The objective of the study was to investigate the possible role of the natural environment i.e. temperature, rainfall and humidity as the primary factors that influence cholera outbreaks in KZN; on the basis of its uniqueness in climatic conditions as compared to other areas of the Republic of South Africa (RSA). The other socio-economical and demographic factors were considered as factors that enhance the spread of the disease. As such, the exploration of the Cholera Database by use of spreadsheet, statistical correlations and spatial mapping using GIS technology mutually investigated the relationships between the different variables that came up as important factors in the spread of cholera. Results indicated that 52% of the total cholera cases in KZN were reported from DC28 (Uthungulu), making it the focal point of the epidemic. In general, all the age groups were represented in the cholera database though the age groups 15-19 years and 0-4 years featured more prominently in the overall epidemic picture. On average the male to female case ratio was 1:1.5 respectively. The major cholera peak was experienced in 2001 and a minor peak in 2002. Both the peaks appeared during the summer months, which are also characterised by heavy rains. The issues that were statistically proven to be associated with the spread of the disease were related to issues highlighting the inefficiencies in the provision of water and sanitation, which go hand in hand with poverty. Thus poverty was indirectly reflected in the data as an issue that compounded the cholera epidemic. There was no statistical correlation between the incidence of cholera and the climatic variables of rainfall, humidity and temperature. Notwithstanding, there was an overall seasonality revealed by the data, as seen with the cases peaking and waning between the summers and the winters respectively. Furthermore, GIS mapping revealed a concurrence between the incidence of cholera and the climatic variables of rainfall, humidity and maximum temperature. At the spatial level, the characteristics of the epidemic as revealed by the GIS maps and spatial modelling highlighted possible relationships between the incidence of cholera and the various socio-economic and climatic variables (Chapter 6: 6.2.3; 6.2.3). The spatial disease picture displayed a link between climatic seasons and the incidence of cholera. Spatial modelling offered more insight that the statistically supported climatic and socio-economic aspects were indeed important factors in guiding cholera outbreak predictions in the future. The cholera model illustrated this as it selected for areas considered to be at high risk for cholera (Map 34). The results give an altogether holistic portrayal of the cholera epidemic from all perspectives and also supported to the hypothesis that cholera is a function of social and environmental factors. The results from this study further confirm the negative health effects of inadequacies in basic services delivery. The study made use of data resources to understand the relationships between the incidence of cholera and the different demographic, socio-economic and climatic variables implicated in the spread of cholera epidemics (Chapter 3: 3.3.3). It also emphasizes the importance of using reliable data as a management tool to model various scenarios in order to obtain information that could be used in the prediction and management of diseases like cholera at the community level in the future. / Thesis (PhD (Water Resource Management))--University of Pretoria, 2006. / Microbiology and Plant Pathology / unrestricted

In this thesis I present three papers on the Economics of the base metals industry. The thesis studies production, trading, and investment in the base metals industry, and thus explains some phenomena of the industry in an international context. Using the features of the base metals industry such as the practices in production and trading, physical properties, geology of the deposits and so on, we build theoretical models to simulate the behavior of the industry. In Chapter One, we study the determinants and the trend of base metals prices over time by an equilibrium model of supply and demand. Because the different types of natural resources exhibit different patterns of price changes in history, we particularly simulate the long run equilibrium to study the impacts of the determinants for base metals prices. The Cobb-Douglass production function on the supply side allows substitution among production factors. The demand function for base metals from the economy is also derived. In the long run, equilibrium of aggregate supply and demand determines the systematic price trend. We show how trends of base metals prices depend on technological progress, resource scarcity, natural resource tax, and the interest rate. Assuming constant returns to scale in base metals production, the price elasticity of the supply of base metals is relatively small. Interestingly, a high natural resource tax leads to a high price but low rate of price change over time. On the supply side, the decline of base metals relative prices can thus be explained by the inverse supply functions. On the demand side, the relative price is also declining over time as we see the implications of the inverse demand functions and our numerical illustrations. By solving the equilibrium condition, we show that the economic rent of base metals minerals in reserve may decline over time, or even not be valuable in future. The price elasticities of supply and demand are calculated and decomposed into specific effects. These are systematic components of base metal price changes in the world market. Chapter Two deals with the fluctuations in the prices of base metals. We consider the price in the short run as an equilibrium of trade. If the long run equilibrium regulates the prices and sets them in a stabilization, then the fluctuations in price are caused by the trade and speculative activities. By simulating speculative activities and optimizing the utility of agents in international exchanges, we show that the price fluctuations are the response to risk preferences of agents and the scale of international exchanges. We find out the critical point of production investment, which depends on the market demand, profitability of the metal industry, and the distribution of base metal minerals in nature. In the specific case of the industry versus the market condition when the uncertain production is above the critical point, the price of base metal fluctuates more or less according to the number of producer offers in base metal exchanges, the speculative activities, and risk preferences of agents. In contrast, if the investment level of the base metals industry in uncertain production is below the critical point, the effects of base metal exchanges scale to the price are in the reverse direction. The comparative statics inequalities are derived to clarify the responses of the price to the risk preferences of agents and scale of the international exchanges. Hence, the non-systematic changes of base metals prices in international exchanges are explained. Chapter Three studies the impact of the industrial and commercial processes on investment decisions in the base metals industry. The investment decisions of investors in the primary capital market and the stock price in the secondary capital market reflect properties of the base metals industry in capital markets. We present a model of investments, which is a two stage game that incorporates Hall-Jorgenson neoclassical investment analysis and properties of the base metals industry. The paper presents a set of explanatory parameters for the properties of base metal stocks and analyzes the investment decisions. We define the industry factor and explain the empirical observations on the beta coefficient of base metal stocks. The relationships between stock prices and base metals prices are clarified using the geology of base metals deposits. The results show that there is a strong impact of the industry factor on the volatility of base metal stock prices. Economies of scale in the mining industry lead to different effects of tax policy and output prices on investment decisions. We support conclusions of the model by evidence in the base metals industry. There are policy implications that are derived from the equations of the optimal investment. Key words : Base Metals, Price Fluctuations, Price Trends, Risk Aversion, Metals Industry, LME, International Exchange, Metal Stocks, Investment.

The thesis will be aimed on problematics of the social politics, concretely on comparison of the Czech republic pension system and Finland pension system. Aim of the theoretical part of thesis will be to explain and clarify problematics of social politics with focus on pension systems. Diploma thesis will also contain strict preview of the pension system from the political view, because pension system is influenced by the political decisions a lot. Aim of the practical part of thesis will be pointing out between pension systems, reveal their pros and cons and finding appropriate implications, if there are some for Czech pension system and suggest possible improvements to the future. Basic hypothesis of this thesis will be then tested on this comparative analysis. Conclusion of this thesis should reveal answer to the question, if there are some principles and mechanisms, Czech republic can be inspired from Finland and if it is appropriate to implicate these principles to the Czech system.