Thesis (MScEng (Industrial Engineering))--University of Stellenbosch, 2011. / ENGLISH ABSTRACT: In terms of its contribution to the agricultural economic activity in Namibia, the small stock industry is the most important sector, second only to the beef industry. This sector makes a significant contribution to the agricultural business in Namibia due to the sector’s exports, its provision of employment, use of natural resources, contribution to GDP and to consumer spending as well as food security. Agricultural activities in Namibia contributed 5.5 percent to Namibia’s GDP, while 70 percent of the population relies on agriculture for employment and day-to-day living. Livestock farming in Namibia is free ranging on natural pastures and therefore produces high-quality meat that is in high demand in both the national and international markets. Small stock production in Namibia is unstable due to the high variability of weather patterns, changes in economic and social environments, unpredictable droughts as well as political and structural changes. Due to the decline in mutton production over the last years, research in the supply economics of the mutton industry in Namibia is important. The purpose of this study is to investigate the relationships between the various price and non-price factors contributing to the supply dynamics within the mutton industry in Namibia. Two hypotheses are tested with the aid of econometric modelling techniques on monthly time series data. The Autoregressive Distributed Lag approach to co-integration was used to determine the long-run and short-run supply response elasticities towards economic and climatology factors. Results showed a significant long-run relationship between the average Namibian mutton producer price and mutton supply. Results revealed that a one percent increase in the mutton producer price leads to a 1.97 percent increase in mutton supply. Beef producer price, a substitute product to mutton, showed a significant negative long-run effect towards mutton production whereas rainfall showed a meaningful positive long-run contribution to mutton supply. These supply shifters towards mutton production also showed significant short-run elasticities. Results further revealed that the system takes nearly two months to recover to the long-run supply equilibrium, should any disturbances occur within the supply system. The study showed that price-related and climatological factors play a major role in the Namibian mutton production industry. Industry stakeholders and policy makers should therefore incorporate these significant relationships between supply shifters and production output into future decisions and marketing policies to secure a healthy, growing and sustainable mutton industry in Namibia. / AFRIKAANSE OPSOMMING: In terme van bydrae tot die landboubedryf in Namibië is die kleinveebedryf die tweede belangrikste sektor, net kleiner as die land se grootveebedryf. Die sektor maak ‘n betekenisvolle bydrae tot die landboubedryf in Namibië deur middel van werkskepping, die gebruik van natuurlike hulpbronne, bydrae tot Bruto Binnelandse Produk, uitvoere, verbruikersbesteding sowel as voedselsekerheid. Landbou-aktiwiteite dra by tot 5,5 persent van die Bruto Binnelandse Produk van ‘n land waar meer as 70 persent van die bevolking afhanklik is van landbou om ‘n bestaan te kan maak. Veeboerdery in Namibië geskied ekstensief op natuurlike veld wat lei tot die produksie van ‘n hoë kwaliteit produk, wat hoog in aanvraag is in plaaslike en internasionale markte. Kleinvee produksie in Namibië is onstabiel as gevolg van fluktuasies in weerpatrone, veranderings in ekonomiese en sosiale omgewings, onvoorspelbare droogtes asook politieke- en struktuurveranderinge. As gevolg van die huidige afname in skaapvleis produksie is navorsing in die aanbodkantekonomie van die skaapvleisbedryf belangrik in Namibië. Die doel van hierdie studie is om die verwantskap te ondersoek tussen verskeie prys en nie-prys faktore wat bydra tot die aanboddinamika van die skaapvleisbedryf. Twee hipoteses word getoets met behulp van ekonometriese modelleringstegnieke op maandelikse tydreeksdata. ‘n Outoregressiewe verspreide sloeringbenadering tot ko-integrasie is gebruik om die langtermyn en korttermyn elastisiteite tussen ekonomiese en klimaatsfaktore vir die aanbod van skaapvleis te bepaal. Resultate dui op ‘n betekenisvolle langtermyn verwantskap tussen die gemiddelde Namibiese produsente prys en skaapvleis produksie. Resultate wys daarop dat ‘n een persent styging in skaapvleis produsente prys ‘n 1,97 persent styging in skaapvleis aanbod het. Die beesvleis produsente prys, ‘n substituut vir skaapvleis, het ‘n beduidende negatiewe effek getoon oor die langtermyn op skaapvleis produksie. Reënval het ‘n beduidende positiewe bydrae getoon ten opsigte van skaapvleis aanbod. Hierdie aanbodsfaktore het betekenisvolle korttermyn elastisiteite getoon. Resultate het ook getoon dat die stelsel twee maande neem om te herstel tot die langtermyn aanbodsewewig, sou daar enige drastiese veranderings in die stelsel plaasvind. Die studie het getoon dat prysverwante en klimaatsfaktore ‘n uiters prominente rol speel met betrekking tot skaapvleisproduksie in Namibië. Bedryfsaandeelhouers en politieke leiers sal hierdie betekenisvolle verwantskappe tussen produksie faktore en aanbod uitset in ag moet neem in toekomstige beplanning en bemarkingsbeleid om ‘n gesonde, groeiende en volhoubare skaapvleisbedryf in Namibië te verseker.

Net energy exporting countries (NEECs) and net energy importing countries (NEICs) depend on each other for mutual gains. However, NEICs pursue strategic policies to reduce consumption of energy from conventional sources and increase that of renewable energy in order to attain energy security and macro environmental and carbon accountability. On the other hand, NEECs such as Nigeria depend heavily on oil and gas exports to NEICs to generate revenue. As a result of this inter-dependent relationship, this PhD project adopts a dependency theory and strategic issue analysis framework to underpin the study. Accordingly, the study approach is founded on the ideas of pluralism as a social reality and adopted pragmatism as the research approach. Consistent with these approaches, the study was undertaken by analysing both secondary and primary data, including macro-economic statistics of annual time-series dataset (1980-2014) and semi-structured interviews respectively. The quantitative part of the project used Auto Regressive Distributed Lag (ARDL) Bounds testing approach. This method was used to investigate and analyse the effect of renewable energy consumption and carbon emissions reduction on Nigeria’s oil and gas exports. The qualitative part involved interviews with twenty senior government officials in Nigeria from six selected Federal Ministries, Departments and Agencies (MDAs), representatives of civil society groups and academicians, to support the quantitative results and answer certain research questions. The short-run quantitative results and qualitative findings show that renewable energy consumption in developed NEICs affects Nigeria’s oil and gas exports. However, the reverse holds true for emerging NEICs. Both the quantitative results and the qualitative findings show that carbon emissions reduction in developed NEICs affects Nigerian oil and gas exports in the long run. Also, the quantitative results show that renewable energy consumption in developed and emerging NEICs does not affect Nigerian oil and gas exports in the long run. However, the qualitative findings only support the quantitative results for emerging NEICs but do not support those of developed NEICs. Similarly, the qualitative findings indicate that other external and internal factors such as discovery of shale oil and gas; improvement in energy efficient technologies; the use of long-term contract in other NEECs; stringent nature of the Nigerian Content Law and lack of passage of the Petroleum Industry Bill amongst others currently contribute in affecting Nigeria’s oil and gas exports. Moreover, the qualitative findings show that global energy transition has an impact on the Nigeria’s oil and gas revenue, savings made to the Nigerian Sovereign Wealth Fund, budget financing and will continue to affect Nigerian revenue and budget if the economy remains undiversified. Finally, the qualitative findings indicate that global energy transition has negatively affected Foreign Direct Investment flow into Nigerian petroleum industry and discoveries of new oil and gas reserves. These findings have several implications. Firstly, Nigerian oil and gas exports are affected by the carbon emissions control regime, which makes future oil and gas revenues uncertain; thereby putting pressure on budget financing and socio-economic growth and development. On this note, there is the need for Nigeria to take cautionary position in the global climate change debate in order not to adversely affect the country’s economic interest. Secondly, the consumption of energy from renewable sources in both developed and emerging NEICs is an opportunity for Nigeria to export not only its conventional energy but also renewable energy if commercially harnessed. This suggests that Nigerian should also invest heavily in renewable energy production. Thirdly, the major findings of this study provide evidence in support of the relevance of dependency theory and strategic issue analysis framework within the context of energy transition in NEICs on one hand, and Nigerian oil and gas exports to these countries on the other. This implies the need for Nigeria to focus on developing internal market trajectories to increase domestic utilisation of its conventional energy rather than being dependent on external markets for the sale of the nation’s energy resources.

The causal relationship between financial development and economic growth is a controversial issue. For developing countries, empirical studies have provided mixed result. This study seeks to empirically explore the relationship and the causal link between financial development and economic growth in two sub-Saharan African countries between 1970 and 2006. The empirical investigation is carried out using time methods and the five most commonly used indicators of financial development in the literature. However, the causal relationship was carried out using two different methods which are the autoregressive distributed lag bounds testing (ARDL) and the vector error correction model (VECM). Using this above methodology the study first found that in both countries there is a positive and long-term relationship between all the indicators of financial development and economic growth which was proxied by the real per capita GDP. With respect to the causality test, the two methods used provide mixed results especially in South Africa. In Cameroon the study found that financial development causes economic growth using the two methods, whereas in South Africa economic growth causes financial development when the VECM method is used, while there is an independence relationship between the two variables in South Africa when using ARDL. / Economics / M.Comm. (Economics)

Esta tese investiga os efeitos agudos da poluição atmosférica no pico de fluxo expiratório (PFE) de escolares com idades entre 6 e 15 anos, residentes em municípios da Amazônia Brasileira. O primeiro artigo avaliou os efeitos do material particulado fino (PM2,5) no PFE de 309 escolares do município de Alta Floresta, Mato Grosso (MT), durante a estação seca de 2006. Modelos de efeitos mistos foram estimados para toda a amostra e estratificados por turno escolar e presença de sintomas de asma. O segundo artigo expõe as estratégias utilizadas para a determinação da função de variância do erro aleatório dos modelos de efeitos mistos. O terceiro artigo analisa os dados do estudo de painel com 234 escolares, realizado na estação seca de 2008 em Tangará da Serra, MT. Avaliou-se os efeitos lineares e com defasagem distribuída (PDLM) do material particulado inalável (PM10), do PM2,5 e do Black Carbon (BC) no PFE de todos os escolares e estratificados por grupos de idade. Nos três artigos, os modelos de efeitos mistos foram ajustados por tendência temporal, temperatura, umidade e características individuais. Os modelos também consideraram o ajuste da autocorrelação residual e da função de variância do erro aleatório. Quanto às exposições, foram avaliados os efeitos das exposições de 5hs, 6hs, 12hs e 24hs, no dia corrente, com defasagens de 1 a 5 dias e das médias móveis de 2 e 3 dias. No que se refere aos resultados de Alta Floresta, os modelos para todas as crianças indicaram reduções no PFE variando de 0,26 l/min (IC95%: 0,49; 0,04) a 0,38 l/min (IC95%: 0,71; 0,04), para cada aumento de 10g/m3 no PM2,5. Não foram observados efeitos significativos da poluição no grupo das crianças asmáticas. A exposição de 24hs apresentou efeito significativo no grupo de alunos da tarde e no grupo dos não asmáticos. A exposição de 0hs a 5:30hs foi significativa tanto para os alunos da manhã quanto para a tarde. Em Tangará da Serra, os resultados mostraram reduções significativas do PFE para aumentos de 10 unidades do poluente, principalmente para as defasagens de 3, 4 e 5 dias. Para o PM10, as reduções variaram de 0,15 (IC95%: 0,29; 0,01) a 0,25 l/min (IC95%: 0,40 ; 0,10). Para o PM2,5, as reduções estiveram entre 0,46 l/min (IC95%: 0,86 to 0,06 ) e 0,54 l/min (IC95%: 0,95; 0,14). E no BC, a redução foi de aproximadamente 0,014 l/min. Em relação ao PDLM, efeitos mais importantes foram observados nos modelos baseados na exposição do dia corrente até 5 dias passados. O efeito global foi significativo apenas para o PM10, com redução do PFE de 0,31 l/min (IC95%: 0,56; 0,05). Esta abordagem também indicou efeitos defasados significativos para todos os poluentes. Por fim, o estudo apontou as crianças de 6 a 8 anos como grupo mais sensível aos efeitos da poluição. Os achados da tese sugerem que a poluição atmosférica decorrente da queima de biomassa está associada a redução do PFE de crianças e adolescentes com idades entre 6 e 15 anos, residentes na Amazônia Brasileira. / This thesis investigates the acute effects of air pollution on peak expiratory flow (PEF) of schoolchildren between the ages of 6 and 15, living in Brazilian Amazon municipalities. The first article evaluated the effects of fine particulate matter (PM2.5) on PEF of 309 schoolchildren in the municipality of Alta Floresta, Mato Grosso (MT), during the dry season in 2006. Mixed effect models were estimated for the whole sample and stratified by the time of the day children attended school, and also by the presence of asthma symptoms. The second article describes the strategies used to determine the random error variance function of mixed effect models. The third one analyzes the data of the panel study with a sample of 234 schoolchildren carried out in Tangará da Serra, MT, during the dry season in 2008. Linear effects and the ones with distributed lag (PDLM) of inhalable particulate matter (PM10), PM2.5 and Black Carbon (BC) were assessed for the whole sample and stratified by age. In all three articles, the mixed effect models were adjusted by time trend, temperature, humidity and personal characteristics. The models also considered the adjustment of the residual autocorrelation and of the random error variance function. Regarding the exposures, its effects were evaluated in 5hs, 6hs, 12hs and 24hs, on the current day, with lags of 1 to 5 days and moving averages of 2 and 3 days. According to results in Alta Floresta, the models for all the children indicated reductions in the PEF varying from 0.26 l/min (CI95%: 0.49; 0.04) to 0.38 l/min (CI95%: 0.71; 0.04), for each increase of 10g/m3 on PM2.5. Significant effects of pollution were not observed in the group of asthmatic children. The 24-hour exposure presented significant effects in the group of students who attended school in the afternoon and in the group of non-asthmatic ones. The exposure from midnight to 5:30 A.M. was significant both to students who attended school in the morning and the ones who studied in the afternoon. In Tangará da Serra, the results showed significant reductions on the PEF for increases of 10 units of pollutants, mainly for lagged exposures of 3, 4 and 5 days. For PM10, the reductions varied from 0.15 (CI95%: 0.29; 0.01) to 0.25 l/min (CI95%: 0.40; 0.10). For PM2.5, the reductions ranged from 0.46 l/min (CI95%: 0.86 to 0.06) to 0.54 l/min (CI95%:0.95; 0.14). And for BC, the reduction was about 0.014 l/min. In relation to PDLM, more important effects were noticed in models based on the exposure of the current day until 5 past days. The global effect was significant only for PM10, with PEF reduction of 0.31 l/min (CI95%: 0.56; 0.05). This approach also indicated significant lagged effects for all pollutants. In the end, this study observed that the children between 6 and 8 years old were the most vulnerable to pollution effects. These findings in the thesis suggest that air pollution due to biomass burning is associated to PEF reduction in children and teenagers between the ages of 6 and 15, living in the Brazilian Amazon.

Esta tese investiga os efeitos agudos da poluição atmosférica no pico de fluxo expiratório (PFE) de escolares com idades entre 6 e 15 anos, residentes em municípios da Amazônia Brasileira. O primeiro artigo avaliou os efeitos do material particulado fino (PM2,5) no PFE de 309 escolares do município de Alta Floresta, Mato Grosso (MT), durante a estação seca de 2006. Modelos de efeitos mistos foram estimados para toda a amostra e estratificados por turno escolar e presença de sintomas de asma. O segundo artigo expõe as estratégias utilizadas para a determinação da função de variância do erro aleatório dos modelos de efeitos mistos. O terceiro artigo analisa os dados do estudo de painel com 234 escolares, realizado na estação seca de 2008 em Tangará da Serra, MT. Avaliou-se os efeitos lineares e com defasagem distribuída (PDLM) do material particulado inalável (PM10), do PM2,5 e do Black Carbon (BC) no PFE de todos os escolares e estratificados por grupos de idade. Nos três artigos, os modelos de efeitos mistos foram ajustados por tendência temporal, temperatura, umidade e características individuais. Os modelos também consideraram o ajuste da autocorrelação residual e da função de variância do erro aleatório. Quanto às exposições, foram avaliados os efeitos das exposições de 5hs, 6hs, 12hs e 24hs, no dia corrente, com defasagens de 1 a 5 dias e das médias móveis de 2 e 3 dias. No que se refere aos resultados de Alta Floresta, os modelos para todas as crianças indicaram reduções no PFE variando de 0,26 l/min (IC95%: 0,49; 0,04) a 0,38 l/min (IC95%: 0,71; 0,04), para cada aumento de 10g/m3 no PM2,5. Não foram observados efeitos significativos da poluição no grupo das crianças asmáticas. A exposição de 24hs apresentou efeito significativo no grupo de alunos da tarde e no grupo dos não asmáticos. A exposição de 0hs a 5:30hs foi significativa tanto para os alunos da manhã quanto para a tarde. Em Tangará da Serra, os resultados mostraram reduções significativas do PFE para aumentos de 10 unidades do poluente, principalmente para as defasagens de 3, 4 e 5 dias. Para o PM10, as reduções variaram de 0,15 (IC95%: 0,29; 0,01) a 0,25 l/min (IC95%: 0,40 ; 0,10). Para o PM2,5, as reduções estiveram entre 0,46 l/min (IC95%: 0,86 to 0,06 ) e 0,54 l/min (IC95%: 0,95; 0,14). E no BC, a redução foi de aproximadamente 0,014 l/min. Em relação ao PDLM, efeitos mais importantes foram observados nos modelos baseados na exposição do dia corrente até 5 dias passados. O efeito global foi significativo apenas para o PM10, com redução do PFE de 0,31 l/min (IC95%: 0,56; 0,05). Esta abordagem também indicou efeitos defasados significativos para todos os poluentes. Por fim, o estudo apontou as crianças de 6 a 8 anos como grupo mais sensível aos efeitos da poluição. Os achados da tese sugerem que a poluição atmosférica decorrente da queima de biomassa está associada a redução do PFE de crianças e adolescentes com idades entre 6 e 15 anos, residentes na Amazônia Brasileira. / This thesis investigates the acute effects of air pollution on peak expiratory flow (PEF) of schoolchildren between the ages of 6 and 15, living in Brazilian Amazon municipalities. The first article evaluated the effects of fine particulate matter (PM2.5) on PEF of 309 schoolchildren in the municipality of Alta Floresta, Mato Grosso (MT), during the dry season in 2006. Mixed effect models were estimated for the whole sample and stratified by the time of the day children attended school, and also by the presence of asthma symptoms. The second article describes the strategies used to determine the random error variance function of mixed effect models. The third one analyzes the data of the panel study with a sample of 234 schoolchildren carried out in Tangará da Serra, MT, during the dry season in 2008. Linear effects and the ones with distributed lag (PDLM) of inhalable particulate matter (PM10), PM2.5 and Black Carbon (BC) were assessed for the whole sample and stratified by age. In all three articles, the mixed effect models were adjusted by time trend, temperature, humidity and personal characteristics. The models also considered the adjustment of the residual autocorrelation and of the random error variance function. Regarding the exposures, its effects were evaluated in 5hs, 6hs, 12hs and 24hs, on the current day, with lags of 1 to 5 days and moving averages of 2 and 3 days. According to results in Alta Floresta, the models for all the children indicated reductions in the PEF varying from 0.26 l/min (CI95%: 0.49; 0.04) to 0.38 l/min (CI95%: 0.71; 0.04), for each increase of 10g/m3 on PM2.5. Significant effects of pollution were not observed in the group of asthmatic children. The 24-hour exposure presented significant effects in the group of students who attended school in the afternoon and in the group of non-asthmatic ones. The exposure from midnight to 5:30 A.M. was significant both to students who attended school in the morning and the ones who studied in the afternoon. In Tangará da Serra, the results showed significant reductions on the PEF for increases of 10 units of pollutants, mainly for lagged exposures of 3, 4 and 5 days. For PM10, the reductions varied from 0.15 (CI95%: 0.29; 0.01) to 0.25 l/min (CI95%: 0.40; 0.10). For PM2.5, the reductions ranged from 0.46 l/min (CI95%: 0.86 to 0.06) to 0.54 l/min (CI95%:0.95; 0.14). And for BC, the reduction was about 0.014 l/min. In relation to PDLM, more important effects were noticed in models based on the exposure of the current day until 5 past days. The global effect was significant only for PM10, with PEF reduction of 0.31 l/min (CI95%: 0.56; 0.05). This approach also indicated significant lagged effects for all pollutants. In the end, this study observed that the children between 6 and 8 years old were the most vulnerable to pollution effects. These findings in the thesis suggest that air pollution due to biomass burning is associated to PEF reduction in children and teenagers between the ages of 6 and 15, living in the Brazilian Amazon.

Submitted by isabela.moljf@hotmail.com (isabela.moljf@hotmail.com) on 2017-06-20T13:47:47Z No. of bitstreams: 1 jeanviniciusmarçal.pdf: 2941702 bytes, checksum: 46f4a5b14de034715ce1e2488e4bd957 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2017-06-29T12:39:39Z (GMT) No. of bitstreams: 1 jeanviniciusmarçal.pdf: 2941702 bytes, checksum: 46f4a5b14de034715ce1e2488e4bd957 (MD5) / Made available in DSpace on 2017-06-29T12:39:39Z (GMT). No. of bitstreams: 1 jeanviniciusmarçal.pdf: 2941702 bytes, checksum: 46f4a5b14de034715ce1e2488e4bd957 (MD5) Previous issue date: 2017-02-16 / Esta dissertação objetivou analisar o mecanismo de transmissão da política monetária para a taxa de juros de varejo na economia brasileira em uma abordagem não linear. O período principal de análise foi de março de 2011 a março de 2016. A estratégia empírica consistiu no emprego da abordagem de política monetária para o repasse e do uso do modelo de cointegração não linear NARDL. Os principais resultados encontrados são que para as taxas de empréstimos analisadas encontrou-se evidência da assimetria de curto e longo prazo no repasse da taxa SELIC. Conclui-se ainda que a transmissão da taxa de juros no Brasil é caracterizada por apresentar o predomínio do sobre repasse. Por fim, ao comparar o período principal com um período anterior, delimitado de janeiro de 2000 a dezembro de 2012, verificou-se a mudança no sinal da assimetria, passando de negativa para positiva no período atual. / This dissertation aims to analyze interest rate pass-through mechanism from SELIC to retail interest rate in the Brazilian economy in a nonlinear framework. The main review period was from March 2011 to March 2016. The empirical strategy consists in the use of monetary policy approach to interest rate pass-through and use of nonlinear cointegration model NARDL. The main results are that exist evidence of short as well as long-term asymmetry in the interest rate pass-through. We can also conclude that the interest rate pass-through is characterized by the predominance of the more complete pass-through. Finally, when comparing the main period with an earlier period, delimited from January 2000 to December 2012, there was a change in the sign of asymmetry, from negative to positive in the current period.

Thesis (M.Com. (Economics)) -- University of Limpopo, 2020 / The remarkable increase in FDI flows to developing countries over the last decade has focused attention on whether this source of financing enhances overall development and growth in the economy. To attain foreign direct investment and sustainable economic growth of a country, balanced budget is not only important but necessary. The aim of the study was to examine the nexus between foreign direct investment (FDI) inflows and budget deficit in a panel of five Southern African Development Community (SADC) countries (Malawi, South Africa, Tanzania, Namibia, and Zambia). The study employed the Panel Auto Regressive Distributed Lag (PARDL) model in examining the relationship between budget deficit and FDI. The panel unit root tests results showed different orders of integration (at levels and first-order) giving way to the use of PARDL. Co-integration test results confirmed a long-run relationship in the budget deficit FDI series. In the long run, there is a significant negative relationship between budget deficit and FDI. The speed of adjustment is 36%, implying that the system would converge faster to equilibrium. Furthermore, Granger causality test results indicated a bi-directional causal link on the interest rate – inflation and interest rate – FDI models. However, there is a unidirectional causality running from budget deficit to FDI; interest rate to the budget deficit and FDI to inflation. It is recommended that government should attract more foreign direct investment so as to minimise budget deficit and this could speed up the development of SADC countries. Key Terms: Foreign direct investment, budget deficit, Autoregressive-Distributed Lag, panel data, Granger causality.

(Ph. D. (Agricultural Economics)) -- University of Limpopo, 2021 / The issues regarding the determinants of agricultural production and food supply are currently of great interest in developing countries. This, in turn, has led to the undertaking of this study focusing on the effectiveness of incentives that can be offered within the agricultural sector to boost production. The study aims to model the supply response of key agricultural commodities to price incentives, price risk and non-price incentives. Special focus is given to four major grain crops, namely; maize, wheat, sorghum and barley, which are of strategic interest to South Africa. The emphasis of the study is on two significant aspects of agricultural supply response: First, an attempt is made to determine the level of price risk among the selected grain crops using two distinct price risk measures. Second, the Autoregressive Distributed Lag-Error Correction Model (ARDL-ECM) approach to cointegration is used to estimate the responsiveness of grain producers to price risk, price incentives and non-price incentives. Annual historical time series data of 49 observations for the period 1970 to 2018 is used in the analysis. Data is tested for stationarity using the Augmented Dickey-Fuller test and the Dickey-Fuller Generalised Least Square (DF-GLS) detrending test. The empirical results reveal that grain supply in South Africa is reasonably responsive to price incentives. However, the degree of responsiveness is low and varies among different crops. Depending on the crop, the results show that own price supply elasticities range from about 0.24 to 0.75. Supply elasticities for nonprice factors are much higher, indicating that non-price incentives (i.e. rainfall, fertiliser, technology) are better production drivers than price incentives in South Africa. Thus, instead of regarding price mechanisms as being the only tools to promote agricultural production, it is concluded that further expansion of irrigation facilities and encouraging the adoption of drought-resistant varieties will stimulate grain production. The results underscore the relevance of price risk in determining production output and show that greater price risk leads to reduced production levels, particularly for maize and barley. In light of such evidence, any policy initiatives undertaken to stabilise the grain industry should look into proposing packages (i.e., forward contracts, futures contracts, contract farming) that reduce the negative impacts of price volatility in grain commodity markets

La dengue est actuellement un problème de santé publique majeur en Colombie avec un fardeau sanitaire et économique important. Les facteurs environnementaux sont connus pour influencer le risque de dengue ; cependant, la forme, l'ampleur et le moment de ces relations ne sont pas clairement établis. L'ampleur et le moment des épidémies de dengue varient selon le lieu. Cette thèse a examiné les composantes temporelles des séries chronologiques hebdomadaires de cas de dengue dans les municipalités de Villavicencio, Castilla la Nueva et Puerto Lopez en Colombie de 2014 à 2019. Il a procédé à l'estimation de la forme et de l'ampleur des associations entre les cas hebdomadaires de dengue et cinq facteurs météorologiques, mesurés chaque semaine, pour chacune des municipalités à l'aide du cadre des modèles non linéaires à décalage distribué avec une distribution binomiale négative. Il a finalement comparé les associations dans les trois municipalités (urbaines, périurbaines et rurales) pour observer si les associations trouvées étaient cohérentes entre les municipalités. Les résultats ont montré que Castilla la Nueva (périurbain) avait la fréquence d'épidémies la plus élevée, avec quatre pics distincts, tandis que Puerto Lopez (rural) en avait le moins. L'ampleur du nombre d'infections était la plus élevée à Villavicencio (urbain), probablement parce qu'elle était la plus peuplée des trois. Les trois municipalités avaient toutes deux une tendance qui dépendait des pics et des creux des flambées de dengue et toutes avaient une composante saisonnière distincte. L'association avec la température, les précipitations, l'humidité relative, la vitesse du vent et la pression de surface à travers les décalages n'était pas linéaire. La non-linéarité a été présentée par un comportement en forme de dôme simple à multiple, dépendant de la municipalité. L'ampleur du risque relatif associé à chaque facteur environnemental dépendait également de la municipalité. Cette thèse propose la création d'un tableau de bord de prévisions utilisant des modèles non linéaires à décalage distribué pour chaque commune comme outil d’aide aux politiques et programmes de lutte contre la dengue. / Dengue is presently a major public health issue in Colombia with significant health and economic burden. Environmental factors are known to influence dengue risk; however the shape, strength and timing of these relationships are not clearly established. The scale and timing of dengue outbreaks vary according to location. This thesis examined the temporal components of weekly dengue cases time series in Villavicencio, Castilla la Nueva and Puerto Lopez municipalities of Colombia from 2014 to 2019. It proceeded to estimate the shape and magnitude of the associations between weekly dengue cases and five meteorological factors, measured weekly, for each of the municipalities using the Distributed lag non-linear models framework with negative binomial distribution. It finally compared the associations across the three municipalities (urban, peri urban, and rural) to observe whether the associations found were consistent across municipalities. The results showed that Castilla la Nueva (peri-urban) had the highest frequency of epidemics, with four distinct peaks, while Puerto Lopez (rural) had the fewest. The magnitude of the number of infections was greatest in Villavicencio (urban), likely as a result of it being the most populated among the three. All three municipalities both had a trend which was dependent on the peaks and troughs of dengue outbreaks and all had a distinct seasonal component. The association with temperature, precipitation, relative humidity, wind speed and surface pressure across lags were non-linear. The non-linearity was exhibited by single to multiple dome-shaped behaviour dependent on the municipality. The magnitude of the relative risk associated with each environmental factor was also dependent on the municipality. This thesis suggest the creation of a dashboard of forecasts of distributed lag non-linear models for each municipality as a policy and program aid, in the fight against dengue.

外人直接投資（foreign direct investment, FDI）在經濟理論中是相當熱門的議題，它代表了讓地主國（host country）國資本累積、技術進步在短時間內快速增加的可能，因此許多國家往往會採取某些吸引外資的政策，再搭配國內制度或是貿易政策的改變，以追求經濟成長。然而，外來直接投資對地主國可能產生的所得重分配的影響，本文即是對此做一深入探討，並以台灣製造業資料來研究外來直接投資是否會擴大工資不均等的情形。 研究期間從1981～2004年共24年，依產業特性將製造業分為十大類，分別採取兩種不同的迴歸模型，包括自我迴歸落遲分配模型（auto regressive distributed lag model, ARDL model）與縱橫資料（panel data）迴歸模型等。實證模型上由生產理論出發，選擇作為解釋工資不均等的變數包括外人直接投資比例、出口比例、進口比例及產出成長率等四個變數。由實證結果得到以下結論： （1）就個別產業來看，FDI對台灣製造業工資不均等的影響並不一致，反應出產業特性不同，FDI所扮演的角色也不盡相同。其中FDI會惡化皮革與毛皮製造業的工資不均等情形，減輕橡膠及塑膠製品製造業與非金屬製品製造業的工資不均等情形，對其他製造業則是無明顯影響。 （2）就整體製造業的情形來看， FDI對工資的不均等的淨效果為正，但效果不大；出口、產出成長率有輕微使工資不均等擴大的情形，而進口則是可輕微縮減工資不均等的狀況。 （3）若是將十大製造業依產品特性區分為「民生」、「化學」、「機械」電子等三大工業，則可以發現FDI對民生工業有明顯擴大工資不均等的情形，在其他兩大工業則是無顯著影響。