Agricultural Expansion, Openness to Trade and Deforestation at the Brazilian Amazon: A Spatial Econometric Analysis

The Brazilian Amazon is a large piece of land that hosts only 12% of Brazilian population. Even this low figure and people mostly living in urban areas, the overexploitation of the forest resources driven by economic activities seems to be out-of-control. In the 1970s, abundant government subsidies/incentives for mining, crop and beef production, and gigantic road projects provided infra-structure to the new settlers coming from other parts of the country. For the last decades, frontier regions of Amazon have been a major scene of land conflicts between farmers, squatters, miners, indigenous group and public authorities. Furthermore, from the openness of economy in the 1990s, we also find some evidence that the very attractive demand of international markets for timber, and recently, the attractive international prices of agricultural commodities are determinants that have been also pushing to more deforestation through the conversion of forest to new agricultural areas. The main objective of this paper is to investigate how international trade has affected the dynamics of deforestation in the Brazilian Amazon. The analysis also focuses on the expansion of crop and cattle activities, and other determinants such as gross domestic product, demographic density and roads. To achieve such goal, we combine standard econometrics with the spatial econometrics in order to capture, across the space, the socio-economic interactions among the agents in their interrelated economic system. The data used in this study correspond to a balanced panel for 732 counties from 2000 to 2007 totalizing 6,256 observations. The main findings suggest that the openness to trade indicator used--export plus import over GDP--goes up, the result is more deforestation. We also find that beef cattle and the production of soybeans, sugarcane and cotton are pushing to more deforestation in the region. The extraction of firewood and timber had both a positive and significant in impact on deforestation, as expected. Moreover, as the GDP goes up, it pushes to more deforestation as well. On the other hand, as the square of GDP goes up indicate less deforestation, supporting, to some extent, the environmental Kuznets Curve hypothesis.

Dynamic Bayesian smooth transition autoregressive models applied to hourly electricity load in southern Brazil

Dynamic Bayesian Smooth Transition Autoregressive (DBSTAR) models are proposed for nonlinear autoregressive time series processes as alternative to both the classical Smooth Transition Autoregressive (STAR) models of Chan and Tong (1986) and the Bayesian Simulation STAR (BSTAR) models of Lopes and Salazar (2005). Unlike those, DBSTAR models are sequential polynomial dynamic analytical models suitable for inherently non-stationary time series with non-linear characteristics such as asymmetric cycles. As they are analytical, they also avoid potential computational problems associated with BSTAR models and allow fast sequential estimation of parameters. Two types of DBSTAR models are defined here based on the method adopted to approximate the transition function of their autoregressive components, namely the Taylor and the B-splines DBSTAR models. A harmonic version of those models, that accounted for the cyclical component explicitly in a flexible yet parsimonious way, were applied to the well-known series of annual Canadian lynx trappings and showed improved fitting when compared to both the classical STAR and the BSTAR models. Another application to a long series of hourly electricity loading in southern Brazil, covering the period of the South-African Football World Cup in June 2010, illustrates the short-term forecasting accuracy of fast computing harmonic DBSTAR models that account for various characteristics such as periodic behaviour (both within-the-day and within-the-week) and average temperature

Avaliação de QoS numa arquitectura Diffserv

Estabeleceu−se uma plataforma de teste com um encaminhador que implementa o paradigma Diffserv. O objectivo principal deste trabalho consistiu na implementação de uma plataforma com um encaminhador de tráfego, implementando o Diffserv. Este encaminhador fazia a admissão, classificação e re−classificação de tráfego, segundo algumas regras, encaminhando−o posteriormente de forma independente e consertada. Este encaminhador revelou que é possível fornecer serviços com qualidade recorrendo à implementação de classes de tráfego, cada uma com características específicas, de forma independente e sem interferências

Evaluating Recommender Systems Qualitatively: A survey and Comparative Analysis

Dissertation presented as the partial requirement for obtaining a Master's degree in Data Science and Advanced Analytics, specialization in Business AnalyticsRecommender systems have improved users' online quality of life by helping them find interesting and valuable items within a large item set. Most recommender system validation research has focused on accuracy metrics, studying the differences between the predicted and actual user ratings. However, recent research has found accuracy to underperform when systems go live, mainly due to accuracy’s inability to validate recommendation lists as a single entity, and shifted to evaluating recommender systems using "beyond-accuracy" metrics, like novelty and diversity. In this dissertation, we summarize and organize the leading research regarding the definitions and objectives of the beyond-accuracy metrics. Such metrics include coverage, diversity, novelty, serendipity, unexpectedness, utility, and fairness. The behaviors and relationships of these metrics are analyzed using four different models, two concerning the items characteristics (item-based) and two regarding the user behaviors (user-based). Furthermore, a new metric is proposed that allows the comparison of different models considering their overall beyond-accuracy performance. Using this metric, a reraking approach is designed to improve the performance of a system, aiming to achieve better recommendations. The impact of the reranking technique on each metric and algorithm is studied, and the accuracy and non-accuracy performance of each system is compared. We realized that, although the reranking technique can increase most beyond-accuracy metrics, the accuracy of that system starts to worsen due to the negative correlation between these two dimensions. We also found that item-based models tend to achieve much lower values of coverage and diversity than userbased models

Processamento e caracterização de extratos fenólicos de macroalgas: uma abordagem sistémica

Mestrado em Biotecnologia MolecularAs políticas industriais do século XXI têm sido pressionadas para uma mudança que torne sustentável o atual paradigma dos mercados e do desenvolvimento económico. A bioeconomia – assente no aproveitamento integral, na valorização e na recirculação das matérias primas utilizadas na indústria, tanto quanto possível de origem biológica - tem sido vista como uma abordagem promissora. A bioprospecção da biomassa para o desenvolvimento de novas aplicações, nomeadamente no isolamento de compostos bioativos, representa uma das linhas de investigação e desenvolvimento (I&D) para a concretização deste objetivo global.A biomassa de origem marinha (e em particular as macroalgas) tem ganho reconhecimento como uma excelente fonte de produtos de valor biotecnológico acrescentado, e a sua exploração constitui a chamada Biotecnologia Azul; para países como Portugal (detentor da 11ª maior zona económica exclusiva do mundo), a valorização estratégica dos mares constitui um importante pilar para o desenvolvimento económico sustentável. Apesar de existirem no mercado produtos derivados de extratos de algas, apenas alguns compostos foram valorizados na sua forma isolada (essencialmente polissacarídeos). Não obstante, os Compostos Fenólicos de Macroalgas (CFMs) – e em especial os florotaninos - são alvo de elevadas expectativas dadas as suas promissoras propriedades biológicas. A valorização destes metabolitos tem ocorrido, contudo, a um ritmo inferior ao expectável, devido à dificuldade em extraí-los de modo sustentável e em caracterizá-los estruturalmente, permanecendo a maioria dos estudos baseada em ensaios espetrofotométricos (pouco específicos). Esta tese propõe, assim, numa primeira fase, uma análise crítica da literatura, de modo a valorizar a informação existente, atualmente dispersa e pouco clara. Como tal, os dados publicados sobre a extração, separação e análise dos CFMs foram compilados e discutidos de forma sistemática. A aplicação de extração assistida por microondas foi revista em maior detalhe, e o uso de cromatografia-espetrometria de massa adequada à análise de florotaninos foi abordada de forma crítica. Nesta secção clarificou-se uma clara deficiência na obtenção e processamento inicial de extratos polares de macroalgas, com o objectivo de estudar os CFMs. A presença de outros metabolitos em quantidades superiores aos de interesse torna-se impeditiva no isolamento e caracterização de CFMs, em contexto académico, e potencia o uso de extratos brutos em vez de frações de valor acrescentado, na indústria. Por isso, numa segunda fase, o problema da co-extração de polissacarídeos com os CFMs é abordado, através do estudo de um processo de adsorção, do qual resultados preliminares são apresentados. Para tal, padrões de compostos modelo (fucoidano e alginato vs. ácido gálico, floroglucinol e catequina) foram usados, e a sua partição entre o solvente e o adsorvente (filtros de celulose vs. celulose microcristalina) avaliada por gravimetria, espetrofotometria e FT-IR. Os dados já obtidos por FT-IR da matriz de celulose após adsorção de uma mistura de polissacarídeos e CFMs revelam que uma maior afinidade da celulose para os polissacarídeos de algas (mantendo a maioria dos CFMs em solução), confirmando o potencial da técnica para uma rápida e eficiente separação destas duas familias.Industrial and economic politics of the XXI century are urging a change towards a more sustainable market and economic development paradigm. Bioeconomy – a paradigm based on integral use, valorization and recirculation of the materials used in industry, as much as possible of biological origin – has been recognized as a potential approach. Bioprospecting biomass for the development of alternatives to current models of human activity, and particularly in the isolation of novel bioactive compounds, is one of the research and development trends towards such global objective. Marine biomass – particularly seaweed - is increasingly considered an excellent source of added-value bio-based assets, and its exploration has given rise to the field of Blue Biotechnology; for countries like Portugal (holding the 11th largest exclusive economic zone), the strategic valorization of the seas constitutes an important part of sustainable economic growth. Despite the existence of some seaweed-derived nutraceuticals and cosmetics in the market, only a few isolated, structurally characterized extractives have been developed so far (essentially polysaccharides used in the food industry). Much potential is, nonetheless, attributed to Seaweed Phenolic Compounds (SPCs) - specially on phlorotannins – due to their diverse, promissing biological properties. However, a gap between the expected potentials of these metabolites and their actual rate of implementation exists, which is mainly a consequence of SPCs being difficult to be sustainably extracted and structurally analyzed. Thus, the majority of the literature in extraction and characterization of SPCs is rather speculative (based on spectrophotometric, non-specific assays. In the first part of this thesis, a critical analysis of the literature is presented, with the goal of making sense of the already existent information, since it is highly dispersed and nuclear. The application of MAE to seaweed bioactives components was deeply dissected, and the use of chromatographic-mass spectrometric setups adequate for the analysis of phlorotannins was critically reviewed. In this part, it could be observed that the problems retarding the study and valorization of SPCs lie on the extraction and initial processing of the polar extracts of seaweed. The presence of other metabolites, more abundant than the target SPCs, impairs a thorough isolation and characterization of these compounds, in an academical context, and promotes the exploration of crude extracts rather than added-value phenolic fractions, in an industrial environment. Thus, in the second part of the thesis, the problem of co-extraction of polysaccharides and SPCs is being addressed by an adsorption-based process, for which preliminar results are here reported. Such experiments were conducted using standard compounds (fucoidan and alginic acid vs. gallic acid phloroglucinol and catechin) to analyze their partition between the solvente and the adsorption matrix (celulose filters vs microcrystaline celulose) by means of gravimetry, spectrophotometry and FT-IR. Data obtained so far from FT-IR of the dried adsorbent after contact with a mixture of polysaccharides-SPCs suggest revealed the higher affinity of celulose for the sugars (with most SPC remaining in solution), confirming the suspected potential of the technique for the separation of these two classes of biomolecules

Custos ecológicos : dilemas dacotonicultura em Mato Grosso

Este trabalho discute os dilemas ecológicos do capital aplicado na cotonicultura no estado de Mato Grosso, no Centro-Oeste do Brasil. O modelo tecnológico utilizado é o chamado de "revolução verde", que se inicia com corte raso da mata nativa e depois estabelece culturas dependentes de insumos químicos, que geram erosão, perda de nutrientes do solo e perda de funções ecossistêmicas. A perda da fertilidade natural força o uso cada vez maior de agrotóxicos e fertilizantes. A estagnação da produtividade da terra conjugada com a elevação dos custos do trabalho mecânico e dos insumos aumenta o custo de produção de algodão, gerando dúvidas sobre a capacidade de competição do ramo. É desta forma que se expressam os custos ecológicos na monocultura do algodão no trópico úmido. Este modelo tecnológico não apresenta sinais de evolução rumo a uma nova racionalidade produtiva agroecológica necessária para recuperar a estrutura e a funcionalidade dos ecossistemas naturais locais e a revitalizar os sistemas de cotonicultura da região.This paper discusses the ecological dilemmas of agrarian capital applied in cotton crops in MatoGrosso. The technological model used has generated strong homogenization of the environment, loss of nutrients in the soil and caused ecological imbalance that has pressed the application of capital in the form of pesticides and fertilizers. The stagnation in productivity of land coupled with the rising costs of pest control has raised the price of cotton, creating doubts about the competition ability of this cluster. The ecological costs involved in the cotton monoculture in the humid tropic can make unviable the present model. This model doesn't show signal of evolution to a new productive rationality capable to sustain the structure and function of ecosystems that support the techno-economic projects