Os estudos realizados em diversas partes do mundo sobre a utilização de pesticidas e os impactos que estes podem causar ao ambiente são uma das ações prioritárias para o desenvolvimento da agricultura, principalmente para aqueles pesticidas que são persistentes ao meio biótico e abiótico, como o inseticida heptacloro, que apesar de seu uso restrito para tratamento de madeira, ainda é muito usado no Brasil clandestinamente para outros fins. A maioria dos estudos realizados até agora sobre biomagnificação envolve o meio terrestre e uma pequena porcentagem desses é direcionada para o meio aquático e tem sido realizada em modelos de campo. O objetivo deste projeto foi determinar a CL50 96 horas para peixes a acumulação, biomagnificação e depuração do heptacloro em um modelo de sistema aquático. Como não existe nenhuma norma que defina o efeito cumulativo através dos níveis tróficos, pretendeu-se com esta pesquisa estimar a biomagnificação e depuração do heptacloro. Este estudo foi realizado em laboratório, em um modelo dividido em compartimentos individualizados, no qual somente as algas (Pseudokirchneriella subcapitata) foram submetidas por um período de 7 dias ao heptacloro, obtendo-se uma concentração final de 0,10 x 10-5µg heptacloro/µg algas, as quais posteriormente serviram de alimento para os microcrustáceos (Daphnia magna) durante 9 dias, que ao final concentraram 0,12 x 10-5 µg heptacloro/µg organismos. Por último, os peixes (Danio rerio) foram alimentados com microcrustáceos, no período de 5 dias, alcançando uma concentração final de 0,62 x 10-8 µg heptacloro/µg organismos. Nos últimos 9 dias, durante o período de depuração, os peixes foram alimentados em dias intercalados com microcrustáceos e ração sem contaminação com o produto, atingindo uma concentração final de 0,25 x 10-8 µg heptacloro/µg organismos. Nos testes realizados com esses três organismos, observou-se que a concentração ficou maior conforme o nível dentro do modelo proposto era mais alto, comprovando assim a hipótese do poder de bioacumulação, biomagnificação e depuração do heptacloro. / The studies carried out in different parts of the world about the pesticides use and the impacts that they can cause to the environment, are one of the priority actions for the agriculture development, mainly for those pesticides that are persistents in the biotic and abiotic environment, such as the heptachlor insecticide, which is still illegally used for others purposes in Brazil, although its use is limited for the wood treatment. The majority of the studies carried out until now about biomagnification involves the terrestrial environment and a small percentage of these studies are directed for the aquatic environment, and this small percentage has been carried out in field models. The aim of this project was to determine the LC50 96 hours for fish, accumulation, biomagnifications, and depuration of heptachlor in an aquatic system model and, as there isn?t any norm that defines the cumulative effect through trophic levels, it was claimed with this research to esteem the heptachlor biomagnification and depuration. This study was carried out in a laboratory, in a model divided in single chambers, in which the algae (Pseudokirchneriella subcapitata were submitted during 7 days to the heptaclhor, getting a final concentration of 0.10 x 10-5µg heptaclhor/µg algae, which was later served as food for the microcrustaceans (Daphnia magna) were submitted during 7 days to the heptaclhor, getting a final concentration of 0.10 x 10-5Mµg heptaclhor/µg algae, which was later served as food for the microcrustaceans (Daphnia magna) were fed with microcrustaceans, in the period of 5 days, reaching a final concentration of 0.62 x 10-8 µg heptaclhor/µg organisms. In the last 9 days, during the period of depuration, the fish were fed in days intercalated with microcrustaceans and ration without contamination with the product, reaching a final concentration of 0.25 x 10-8 µg heptacloro/µg organisms. In tests carried out with these three organisms, it was observed that the concentration was bigger as higher the level inside of the considered model, thus proving the hypothesis of the bioaccumulation, biomagnification, and depuration power of heptachlor.

As minimelancias foram desenvolvidas para atender a uma demanda por frutos de menor tamanho, mais fáceis de transportar e mais adequadas ao consumo de pequenas famílias. A produção comercial de melancia sob cultivo protegido no Brasil ainda é incipiente. O cultivo vertical, mesmo que dispendioso em razão da demanda de mão-de-obra, facilita as operações nos tratos culturais e permite ganho em produtividade por meio do aumento da densidade de plantas, além de melhorar a qualidade de frutos. Para esse sistema de produção de melancia, pouco se dispõe de informações técnicas. Foram realizados dois experimentos: o primeiro visando determinar a demanda evapotranspirativa, a eficiência de uso da água e os efeitos de cinco níveis de nitrogênio e cinco níveis de potássio em de três relações N: K, na produção e qualidade de frutos; o segundo experimento teve o objetivo de avaliar os efeitos de três tratamentos de fertilizantes em três sistemas de condução de planta e a obtenção das curvas de acúmulo de massa seca e acúmulo de nutrientes. No primeiro ciclo observou-se uma tendência de a relação 1:2 ser mais produtiva e, também, de as doses próximas às mais baixas produzirem mais. Com relação à demanda evapotranspirativa, o maior consumo diário registrado foi de 1,295 L, enquanto o consumo total médio ao final do ciclo foi de 26,48 L planta-1, com eficiência de uso da água de 21,8 L kg-1, melhor que os resultados mais promissores encontrados na literatura. No segundo ciclo, os sistemas de condução de plantas 1 e 3 foram mais precoces em até 22 dias e o sistema de condução 2 proporcionou maior produtividade e maior acúmulo de massa seca para as três soluções nutritivas. Em ordem decrescente, o acúmulo de nutrientes apresentou respectivamente: K > N > Ca > P > Mg > S > Fe > Mn > Zn > B > Cu. O custo de produção de um ciclo nesse sistema foi de R$ 17.538,82, sendo 60,47 % o custo da infra-estrutura física. Baseando-se na menor produção prevista, o preço de mercado não deve ser inferior a R$ 0,77 kg-1 para o produtor cobrir seus custos. / Mini watermelon was developed to supply demand for smaller fruit size, easier to carry and more appropriate to use by small families, as a result it has high added value. Commercial production of watermelon under protected cultivation is still new in Brazil. Vertical growing is costly due to labour cost; however it facilitates cultural practices and allows higher productivity by increasing density of plants, in addition to improving fruit quality. Technical information for this production system is scarce. Two experiments were carried out, the first one determined evapotranspiration demand, water-use efficiency and effects of five levels of nitrogen and potassium with three relations N:K, as well as production and fruit quality. The second experiment evaluated effects of three fertilizers levels in three plant conduction systems and accumulation curves of dry mass and nutrients were fitted. In the first cycle the ratio 1:2 trended to be more productive and lower dosages had high production. In this cycle the maximum daily water consumption was 1295 L, while average total consumption at the end of cycle was 26.64 L/plant and water-use efficiency was 21.9 L/kg, which is upper than the best results obtained in past studies. In the second cycle, one and three types of plant conduction systems were earlier in up to 22 days, and two type of plant conduction system provided higher productivity and greater accumulation of dry mass for three nutrient solutions. In order of importance the accumulation of nutrients presented respectively: K > N > Ca > P > Mg > S > Fe > Mn > Zn > B > Cu. Production cost of one cycle in this system was US$ 11,100.00 with 60.47% of referring to cost of physical infrastructure. Based on lower production predicted, the market price should not be less than US$ 0.49 kg-1, for cover production costs.

Nesta dissertação foram analisados os projetos de divisão territorial do Pará a partir da criação dos estados do Carajás e do Tapajós, os quais estão sobrepostos à fronteira de acumulação, isto é, a territórios onde a acumulação por espoliação é ampliada. Esses movimentos de divisão territorial traduzem, fundamentalmente, os interesses de frações da classe capitalista em se apropriar dos territórios em questão (Sudeste e Oeste paraenses), apropriação que, junto das ideologias geográficas, forma um par indissociável para a expansão geográfica do capital na Amazônia Oriental. / In this dissertation, the projects of the division of the Pará territory based on the creation of the Carajás state and the Tapajós state were studied. These states were created on an accumulation border that is to say territories where the accumulation by spoliation is amplified. These territorial division movements represent, fundamentally, the interests of fractions of the capitalist class in claiming ownership of the territories in question (south-west and west of the Pará), this appropriation has, in geographic ideologies, an inseparable link with the geographic expansion of the capital to the Eastern Amazon.

A metrópole de São Paulo passa por profundas transformações desde a década de 1990. O chamado vetor sudoeste se elaborou como a novacentralidade econômica do país. Esse processo se remete à reprodução do espaço urbano como condição, meio e produto da acumulação de capital. A potência desse fenômeno e dessa condição é relativamente nova. A história da concentração geográfica do capitalna cidade de São Paulo favoreceu sempre a abertura de novas oportunidades de investimentos in loco, mas a intensidade do processo aumenta exponencialmente quando um movimento de concentração começa a dar lugar à centralização geográfica do capital.A partir daí, a concentração se torna, ela mesma, a condição de reposição de novas oportunidades de investimentos na centralidade constituída, numa dinâmica que consome configurações espaciais previamente capitalistas. Trata-se de uma acumulação especificamente urbana. No Brasil, essa dinâmica espacial do capital não foi tão significativa até a década de 1990. A hipótese que explica esse descompasso no caso brasileiro reconhece a prioridade do processo de produção sobre a reprodução do espaço urbano. Isso significa que a urbanização se estendeu no tempo porque pôde se estender no espaço. A urbanização expandida do território brasileiro foi aqui objeto da ação de um Estado comprometido com a realização do capital e assim absorveu lucrativamente os excedentes frequentemente gerados na economia brasileira. Com a crise do Estado desenvolvimentista e com as condições apresentadas nos grandes centros nacionais, o processo de valorização exigiu mais do que se podia conseguir com a manutenção de uma enfraquecida dinâmica expansionista. Aqui o Estado se reorganiza e cria novos instrumentosque o permitem atuar na escala metropolitana. A produção de novas centralidades, como momento da reprodução do espaço urbano, e a centralização geográfica diminuem a importância das dinâmicas expansionistas na realização do capital. A intensificação geográfica do capital, na era das finanças mundializadas, passa a compor o centro das estratégias de acumulação. / The metropolis of São Paulo has undergone profound changes since the 1990s. The so-called southwest vector has established itself as the new economic centre in the country. This process relates to the reproduction of the urban space as a condition, means and product of capital accumulation. The strength of this phenomenon and of this condition is relatively new. The history of the geographical concentration of capital in the city of São Paulo has always privileged new investment opportunitiesin loco, however, whenever the movement of concentration starts to give way to geographic centralization of capital, the process intensifies exponentially. At this point, the concentration itself becomes the condition for the reestablishment of new investment opportunities in the recently instituted centrality: a dynamics that consume previous capitalist spatial configurations. And thisis a specifically urban accumulation. In Brazil, the spatial dynamics of capital had not been significant until the 1990s decade. The hypothesis used to explain the mismatch in the case of Brazil recognizes the priority of the production process over thereproduction of the urban space. That means that the urbanization has extended in time just because it could extend in space. The expanded urbanization of the Brazilian territory has been the result of a state policy committed to capital development, therefore, it has absorbed profitably the surpluses frequently generated in the Brazilian economy. Due to the crisis of developmentalism and the conditions prevailing in the major national centers, the valorization process required more than could be achieved with the maintenance of a weak expansionist dynamics. From this point on, the state reorganizes itself and creates new instruments that permit action at the metropolitan scale. The production of new centers, as a dimension of the reproduction of urban space, as well as the geographical centralization, diminish the importance of the expansionist dynamics for capital. In the age of global finance, the geographical intensification of capital becomes the mainstay of accumulation strategies.

Área de risco é um conjunto de quinze proposições poéticas que apresenta um estudo sobre a expressão das oposições sensórias geradas na acumulação e/ou repetição de objetos de uso cotidiano. Tendo as ambivalências sensórias entre os corpos dos objetos como foco de pesquisa, o trabalho estabelece relações entre os conceitos de extensão e intensidade, matérias e qualidade. A investigação inclui ainda temas como o da coleção, da trivialidade, da uniformidade, da heterogeneidade, da regularidade e da artesania, A criação de campos sensórios instaura zonas de vizinhança entre seres de natureza diversa, capazes de dissolver as formas cristalizadas e de recriar, por toda parte, uma visão inventora de blocos de sensação. / Risk area is an ensemble of fifteen poetic propositions that present a study on the expression of sensory oppositions created by the accumulation and/or repetition of eveyday objects. Focusing on the sensory ambivalences between the bodies of the objects, the work estabilishes relationships between the concepts of extension and intensity, and matter and quality. The research also includes topics such as collection, trivia, consistency, heterogeneity, regularity and artisanship, The creation if sensory fields introduces zones of proximity between beings of different natures, capable of dissolving the crystalized forms and recreating, everywhere, a vision designing sensations blocks

We present a method for stable buildup of snow on surfaces of arbitrary topology and geometric complexity. This is achieved by tracing quantities of snow, so-called snow packages, through a dynamic wind field. Dual compact level sets are used to represent geometry as well as accumulated snow. The level sets have also proven to be well suited for the internal boundaries for our Navier-Stokes solver, which produces a wind field that changes according to snow buildup. Our method is different from previous work in that all the addition of snow is done by local operations, avoiding computationally expensive global refinement procedures. The main contribution of this work is a dual level set method for particle interaction with level sets.

Previous research has shown a social gradient in health that suggests that better health is found for people in more advantaged positions in society. This research has mainly been focused on the relationship between social position in childhood and health or current position and health. However, little is known about the impact of positions held in between these two time-points. In this paper a potentially lasting health effect of occupational class positions is explored. The study starts with a description of the work-life biographies for people in different current class positions. Then goes on to investigate if the effect of current class is modified when including previous positions during adulthood, as well as how much extra information is gained by utilizing information on individual work histories. An association between accumulated experience of manual working class and self-rated health is found. Also, when controlling for accumulated class experience, the social gradient for current class is no longer significant. Furthermore, even for non-manual employees the odds of reporting less than good self-rated health is increasing with each added year of previous manual experience. This suggests that the social gradient in health is more complex than just a matter of current social position influencing current health, and that the effects would potentially be modified if the full complexity of life-time social positions were taken into account.

The Zambian government, through the Ministry of Agriculture and Cooperatives (MACO), provides maize seed and fertilizers to farmers at heavily subsidised prices under the Farmer Input Support Programme (FISP). MACO’s narrow evaluation of FISP, based on estimated production without quantifying the significant changes in production and other critical socioeconomic factors, fails to adequately highlight and service the benefits of subsidies to intended beneficiaries. Furthermore, MACO estimates of the impact of FISP never consider the question of how much beneficiary farmers would have produced in its absence, leading to potentially misleading assessments. The key question addressed in this study is whether using more rigorous econometric methods that account for heterogeneity in socioeconomic factors between participants and non-participants would still confirm the positive impact of FISP on maize productivity and poverty reduction, hence justifying the huge government expense on the programme. The study utilised cross-sectional data obtained from 497 randomly selected households, collected in 2011 from six provinces of Zambia to assess the causal effect of FISP on beneficiary households’ maize yields and asset accumulation. The data was analysed using well-grounded matching techniques that account for differences in observable characteristics between programme participants and non-participants. The study also tested for possible unobserved selection effects using the Rosenbaum bounds. The results indicated that participating in FISP increased maize yields and assets accumulation and hence might directly or indirectly positively affect beneficiary poverty levels. There were also no influences of unobserved characteristics on the estimated maize yield and asset level differences between participants and non-participants. On average, FISP increased maize yields by about 451 kg per hectare, with an improvement of about 0.5 on the wealth index (score used to rank households according to asset levels). The positive impact on maize yields and asset accumulation on the participating farmers therefore justifies government’s continued implementation of FISP. / Dissertation (MScAgric)--University of Pretoria, 2014. / lk2014 / Agricultural Economics, Extension and Rural Development / MScAgric / Unrestricted

Improving the hydraulic performance of waste stabilization ponds (WSPs) is an important management strategy to not only ensure protection of public health and the environment, but also to maximize the potential reuse of valuable resources found in the treated effluent. To reuse effluent from WSPs, a better understanding of the factors that impact the hydraulic performance of the system is needed. One major factor determining the hydraulic performance of a WSP is sludge accumulation, which alters the volume of the pond. In this study, computational fluid dynamics (CFD) analysis was applied to investigate the impact of sludge layer geometry on hydraulic performance of a facultative pond, typically used in many small communities throughout the developing world. Four waste stabilization pond cases with different sludge volumes and distributions were investigated. Results indicate that sludge distribution and volume have a significant impact on wastewater treatment efficiency and capacity. Although treatment capacity is reduced with accumulation of sludge, the latter may induce a baffling effect which causes the flow to behave closer to that of plug flow reactor and thus increase treatment efficiency. In addition to sludge accumulation and distribution, the impact of water surface level is also investigated through two additional cases. Findings show that an increase in water level while keeping a constant flow rate can result in a significant decrease in the hydraulic performance by reducing the sludge baffling effect, suggesting a careful monitoring of sludge accumulation and water surface level in WSP systems.

Philosophiae Doctor - PhD / Global climate change has resulted in altered rainfall patterns, causing annual losses in maize crop yield due to water deficit stress. Therefore, it is important to produce maize cultivars which are more drought-tolerant. This not an easily accomplished task as plants have a plethora of physical and biochemical adaptation methods. One such mechanism is the drought-induced expression of enzymatic and non-enzymatic proteins which assist plants to resist the effects of water deficit stress. The RD22-like protein subfamily is expressed in response to water deficit stress. Members of the RD22-like subfamily include AtRD22, GmRd22 and BnBDC1 which have been identified in Arabidopsis thaliana, Glycine max and Brassica napus respectively. This study aims at characterising two putative maize RD22-like proteins (designated ZmRd22A and ZmRd22B) by identifying sequence/domain features shared with characterised RD22-like proteins. Semi-quantitative and quantitative PCR techniques were used to examine the spatial and temporal expression patterns of the two putative maize Rd22-like proteins in response to, water deficit stress and exogenously applied abscisic acid in the roots and 2nd youngest leaves of maize seedlings. Using an in silico approach, sequence homology of the two putative maize Rd22- like proteins with AtRD22, GmRD22 and BnBDC1 has been analysed. Online bioinformatic tools were used to compare the characteristics of these Rd22-like proteins with those of the two maize proteins. It was shown that the putative maize RD22-like proteins share domain organisation with the characterised proteins, these common features include a N-terminal hydrophobic signal peptide, followed by a region with a conserved amino acid sequence, a region containing several TxV (x is any amino acid) repeat units and a C-terminal BURP domain-containing the conserved X₅-CH-X₁₀-CH-X₂₃-₂₇-CH-X₂₃-₂₆-CH-X₈-W motif. The putative maize Rd22-like protein appears to be localized in the apoplast, similarly to AtRD22, GmRD22 and BnBDC1. Analysis of the gene's promotor regions reveals cis-acting elements suggestive of induction of gene expression by water deficit stress and abscisic acid (ABA). Semi-quantitative and quantitative real time PCR analysis of the putative maize RD22-like gene revealed that the genes are not expressed in the roots. Exposure to water deficit stress resulted in an increase of ZmRD22A transcript accumulation in the 2nd youngest leaves of maize seedlings. ZmRD22A was shown to be non-responsive to exogenous ABA application. ZmRD22B was highly responsive to exogenous ABA application and responded to water deficit stress to a lesser degree. Transcript accumulation studies in three regions of the 2nd youngest leaves in response to water deficit stress showed that ZmRd22A transcripts accumulate mainly at the base and tips of the leaves. A restricted increase in ZmRD22A transcript accumulation in the middle of the leaves was observed. ZmRD22B showed a similar, but weaker transcript accumulation pattern in response to water deficit stress. However, ZmRD22B showed increased transcript accumulation in the middle region of the leaves. In response to exogenous ABA application, ZmRd22B exhibited high transcript accumulation at the base of the 2nd youngest leaves, with the middle showing higher transcript accumulation than the tip of the leaves. It was concluded that ZmRD22A and ZmRD22B share the domain organisation of characterised RD22-like proteins as well as being responsive to water deficit stress, although only ZmRD22B was shown to be responsive to exogenous ABA application. / National Research Foundation (NRF)