The incompatible behaviour of gold in reduced magmas : a working hypothesis

O ouro apresenta comportamento distinto ao longo da evolução magmática, de acordo com a fO2 do magma. Em condições oxidantes, caracterizadas pela presença de magnetite como a principal fase de óxido de Fe-Ti, a concentração de ouro em rochas plutóinicas diminui com a diferenciação. No entanto, em condições redutoras, caracterizadas pela predominância de ilmenite, a concentração de ouro em rochas plutónicas aumenta com a diferenciação. Neste trabalho, comparam se as estruturas das fases de óxido de Fe-Ti (magnetite e ilmenite) com os possíveis iões de ouro (auroso, Au+; e aurico, Au3+). É formulada a hipótese de sob condições mais oxidantes ocorrer ouro aurico que, devido a ter um raio iónico similar ao ferro ferroso e, até certo ponto, férrico, é facilmente incorporado na magnetite que vai cristalizando, pelo que a magnetite actua como um sumidouro para o ouro e leva à sua progressiva remoção do magma. Sob condições mais redutoras, o único ião de ouro presente é o auroso que, devido ao seu grande raio iónico, não é passível de ser incorporado na ilmenite (nem possivelmente na magnetite). Deste modo, o ouro comporta se como um elemento incompatível e tende a acumular se em fluidos tardios, ficando disponível para levar à formação de mineralizações auríferas

Exergy cost of mineral resources

Mineral deposits are considered as natural capital whose value can be assessed in exergy terms. Historical industry experience provides evidence that exploitation of mineral deposits and the beneficiation of ores are essentially energy intensive. The persisting decline of the grade of the developed deposits demands increasing exergy replacement and processing costs. The results demonstrate how far processed ores and concentrates are from ideal behaviour, and technologies from reversibility conditions. The exploitation of mineral resources of declining quality for mineral commodities imply a long time trend of increasing mass and exergy inputs spent per unit product output, in line with a law of ‘diminishing returns’ on invested exergy

Automatic learning for the classification of chemical reactions and in statistical thermodynamics

This Thesis describes the application of automatic learning methods for a) the classification of organic and metabolic reactions, and b) the mapping of Potential Energy Surfaces(PES). The classification of reactions was approached with two distinct methodologies: a representation of chemical reactions based on NMR data, and a representation of chemical reactions from the reaction equation based on the physico-chemical and topological features of chemical bonds. NMR-based classification of photochemical and enzymatic reactions. Photochemical and metabolic reactions were classified by Kohonen Self-Organizing Maps (Kohonen SOMs) and Random Forests (RFs) taking as input the difference between the 1H NMR spectra of the products and the reactants. The development of such a representation can be applied in automatic analysis of changes in the 1H NMR spectrum of a mixture and their interpretation in terms of the chemical reactions taking place. Examples of possible applications are the monitoring of reaction processes, evaluation of the stability of chemicals, or even the interpretation of metabonomic data. A Kohonen SOM trained with a data set of metabolic reactions catalysed by transferases was able to correctly classify 75% of an independent test set in terms of the EC number subclass. Random Forests improved the correct predictions to 79%. With photochemical reactions classified into 7 groups, an independent test set was classified with 86-93% accuracy. The data set of photochemical reactions was also used to simulate mixtures with two reactions occurring simultaneously. Kohonen SOMs and Feed-Forward Neural Networks (FFNNs) were trained to classify the reactions occurring in a mixture based on the 1H NMR spectra of the products and reactants. Kohonen SOMs allowed the correct assignment of 53-63% of the mixtures (in a test set). Counter-Propagation Neural Networks (CPNNs) gave origin to similar results. The use of supervised learning techniques allowed an improvement in the results. They were improved to 77% of correct assignments when an ensemble of ten FFNNs were used and to 80% when Random Forests were used. This study was performed with NMR data simulated from the molecular structure by the SPINUS program. In the design of one test set, simulated data was combined with experimental data. The results support the proposal of linking databases of chemical reactions to experimental or simulated NMR data for automatic classification of reactions and mixtures of reactions. Genome-scale classification of enzymatic reactions from their reaction equation. The MOLMAP descriptor relies on a Kohonen SOM that defines types of bonds on the basis of their physico-chemical and topological properties. The MOLMAP descriptor of a molecule represents the types of bonds available in that molecule. The MOLMAP descriptor of a reaction is defined as the difference between the MOLMAPs of the products and the reactants, and numerically encodes the pattern of bonds that are broken, changed, and made during a chemical reaction. The automatic perception of chemical similarities between metabolic reactions is required for a variety of applications ranging from the computer validation of classification systems, genome-scale reconstruction (or comparison) of metabolic pathways, to the classification of enzymatic mechanisms. Catalytic functions of proteins are generally described by the EC numbers that are simultaneously employed as identifiers of reactions, enzymes, and enzyme genes, thus linking metabolic and genomic information. Different methods should be available to automatically compare metabolic reactions and for the automatic assignment of EC numbers to reactions still not officially classified. In this study, the genome-scale data set of enzymatic reactions available in the KEGG database was encoded by the MOLMAP descriptors, and was submitted to Kohonen SOMs to compare the resulting map with the official EC number classification, to explore the possibility of predicting EC numbers from the reaction equation, and to assess the internal consistency of the EC classification at the class level. A general agreement with the EC classification was observed, i.e. a relationship between the similarity of MOLMAPs and the similarity of EC numbers. At the same time, MOLMAPs were able to discriminate between EC sub-subclasses. EC numbers could be assigned at the class, subclass, and sub-subclass levels with accuracies up to 92%, 80%, and 70% for independent test sets. The correspondence between chemical similarity of metabolic reactions and their MOLMAP descriptors was applied to the identification of a number of reactions mapped into the same neuron but belonging to different EC classes, which demonstrated the ability of the MOLMAP/SOM approach to verify the internal consistency of classifications in databases of metabolic reactions. RFs were also used to assign the four levels of the EC hierarchy from the reaction equation. EC numbers were correctly assigned in 95%, 90%, 85% and 86% of the cases (for independent test sets) at the class, subclass, sub-subclass and full EC number level,respectively. Experiments for the classification of reactions from the main reactants and products were performed with RFs - EC numbers were assigned at the class, subclass and sub-subclass level with accuracies of 78%, 74% and 63%, respectively. In the course of the experiments with metabolic reactions we suggested that the MOLMAP / SOM concept could be extended to the representation of other levels of metabolic information such as metabolic pathways. Following the MOLMAP idea, the pattern of neurons activated by the reactions of a metabolic pathway is a representation of the reactions involved in that pathway - a descriptor of the metabolic pathway. This reasoning enabled the comparison of different pathways, the automatic classification of pathways, and a classification of organisms based on their biochemical machinery. The three levels of classification (from bonds to metabolic pathways) allowed to map and perceive chemical similarities between metabolic pathways even for pathways of different types of metabolism and pathways that do not share similarities in terms of EC numbers. Mapping of PES by neural networks (NNs). In a first series of experiments, ensembles of Feed-Forward NNs (EnsFFNNs) and Associative Neural Networks (ASNNs) were trained to reproduce PES represented by the Lennard-Jones (LJ) analytical potential function. The accuracy of the method was assessed by comparing the results of molecular dynamics simulations (thermal, structural, and dynamic properties) obtained from the NNs-PES and from the LJ function. The results indicated that for LJ-type potentials, NNs can be trained to generate accurate PES to be used in molecular simulations. EnsFFNNs and ASNNs gave better results than single FFNNs. A remarkable ability of the NNs models to interpolate between distant curves and accurately reproduce potentials to be used in molecular simulations is shown. The purpose of the first study was to systematically analyse the accuracy of different NNs. Our main motivation, however, is reflected in the next study: the mapping of multidimensional PES by NNs to simulate, by Molecular Dynamics or Monte Carlo, the adsorption and self-assembly of solvated organic molecules on noble-metal electrodes. Indeed, for such complex and heterogeneous systems the development of suitable analytical functions that fit quantum mechanical interaction energies is a non-trivial or even impossible task. The data consisted of energy values, from Density Functional Theory (DFT) calculations, at different distances, for several molecular orientations and three electrode adsorption sites. The results indicate that NNs require a data set large enough to cover well the diversity of possible interaction sites, distances, and orientations. NNs trained with such data sets can perform equally well or even better than analytical functions. Therefore, they can be used in molecular simulations, particularly for the ethanol/Au (111) interface which is the case studied in the present Thesis. Once properly trained, the networks are able to produce, as output, any required number of energy points for accurate interpolations

Effect of U.S. Federal Budget on S&P 500 Index

I propose in this paper to understand and explain how the publication and acceptance of the United States federal budget affects the stock market returns of the largest 500 U.S. companies by market capitalization. It is analyzed the impact of each category of expenditure from the U.S. budget in stock market returns. Further, it was also tested if presidential elections years had any effect on stock prices. It is represented in this study the 2002 to 2012 U.S. budget publications and 10 sectors indexes from the S&P 500 index. I verified that the President’s budget publication does not lead to any significant return to the S&P 500 index, but leads to a positive and significant return on the Consumer Discretionary and Materials sectors and negative and significant return to the Technology sector. The budget acceptance and the presidential elections years had no significant effect in stock market returns in this study. The way how U.S. government spends its money in the U.S. federal budget is represented in each category’s expenditures of the budget, which does not affect any sector of the U.S. economy

CASA DE FÉRIAS: ORIGEM, REFERÊNCIAS, PROJETO.

Um projeto de uma casa de férias. Um trabalho de projeto para atingí-lo. Goios, Barcelos, mais concretamente a Rua de Escavinhos, é o local escolhido pelo cliente para a execução de um projeto. O plano, delineado pelo cliente, visa a construção de uma nova casa de férias de utilização esporádica. Este trabalho, como o título indica: “Uma casa de férias: Origem, Referências, Projeto.”, pretende levar-nos num caminho sobre três pontos de pensamento intelectual e intuitivo do arquiteto. Sendo assim, pretende-se apresentar, durante o trabalho de projeto, o processo que se desenvolveu ao longo da tese, a origem, onde ocorre troca de ideias entre o autor e os proprietários, o confronto das motivações e impulsos pessoais com as condicionantes e mais valias que se foram colocando, desde o programa, o próprio relacionamento com os clientes e a topografia. Numa segunda fase da viagem, encontramos a busca pelas referências, que nos leva à procura no consciente e subconsciente, não só na arquitetura, mas em pinturas e filmes. No final, encontramos o terceiro e último capítulo, o projeto, onde este se mostra desde o início até à constante evolução e desenvolvimento do trabalho realizado nalgumas fases. Desta forma, termina-se este ciclo, que corresponde ao fim do percurso académico, trabalho que se apresenta na presente dissertação, e que tem como objetivo formar e preparar para a prática da arquitetura em contexto real

La violencia sexual intrafamiliar contra Niños, Niñas y Adolescentes: Consideraciones sobre la protección jurídica y el enfrentamiento en Brasil

Anais das IV Jornadas Internacionais de Problemas Latino-Americanos: Lutas, Experiências e Debates na América Latina - ISBN 978-950-793-223-6 - Orgs. Paulo Renato da Silva ; Mario Ayala ; Fabricio Pereira da Silva ; Fernando José MartinsBuscar-se-á estudar a proteção jurídica nacional e internacional dos direitos da criança e do adolescente, a teoria da proteção integral, a violência sexual intrafamiliar contra crianças e ado- lescentes e as políticas públicas de enfrentamento da situação de violência e de efetivação de direi- tos fundamentais durante à infância.PPG – IELA – UNIL

Segmentação de pele em imagens digitais para a detecção automática de conteúdo ofensivo

This work presents a study of suitable approaches for automatic detection of offensive content (pornography) in digital images. Extensive experiments were conducted for skin pixel segmentation, colour spaces and content descriptors. This work focus its efforts on skin pixel segmentation, since this segmentation is the pre-processing stage for almost every content-based offensive image classification methods in the literature. Four skin skin segmentation methods were tested in six colour spaces. Also, a structured image database was built to help improve studies in skin segmentation, with the possibility of adding meta-information to the images in the database, such as illumination conditions and camera standards. With the help of meta information from the image database, experimets involving illumination conditions and skin colour segmentation were also done. Finally, some feature extraction algorithms were implemented in order to apply content-based image retrieval (CBIR) algorithms to classify offensive images.CAPES; UOLO presente trabalho tem como objetivo estudar meios de efetuar a detecção automática de conteúdo ofensivo (pornografia) em imagens digitais. Para tal estudou-se largamente segmentação de pixels de pele, espaços de cor e descritores de conteúdo. Esse trabalho tem um foco maior na segmentação de pele, pois é a etapa primordial nos trabalhos envolvendo detecção de conteúdo ofensivo. Testou-se quatro métodos de segmentação de pixels de pele e foi construído um banco de dados estruturado para o estudo de segmentação de pele, com meios de anotação de imagens para auxiliar na estruturação e no controle das características das imagens do banco. Com o auxílio das metainformações do banco de imagens, foram conduzidos estudos envolvendo as condições de iluminação e a segmentação de pele. Por fim, foi implementado um algoritmo de extração de características em sistemas de classificação pelo conteúdo de imagens (CBIR) para detecção de conteúdo ofensivo

Estrutura do dossel e sazonalidade do índice de área foliar em ambientes de terra firme na Amazônia Central, com uso do LiDAR portátil terrestre

The objective of this study was to investigate the structural differences of the canopy and its seasonal variation in four environments of terra firme in the Central Amazon. Structural attributes of the forest canopy were obtained, using a rangefinder LiDAR, which provides the distance to the last return for each of 1,000 pulses per second. The sensor was aimed upwards and held 1m above the forest floor to obtain 150m long forest canopy profiles at a constant walking speed. Each of four different forest types that comprise a toposequence (catena) was profiled, with six replicates (total 900m of transect per type) at monthly intervals for a full year. From the highest to the lowest, the catena compartments were: plateau on well drained clay-loam; upper slope on well drained clay-loam; gentle lower slope on white sand (tall campinarana forest); and seasonally waterlogged riparian zone on white sand (baixio forest). For each 150m transect, the canopy structure profile was represented by a 2D point cloud containing the positions (x, z) of ~ 345,000 LiDAR last-returns. The main features extracted were: (1) top-of-canopy height in each 1m horizontal interval; (2) the mean and standard deviation (roughness) of these 150 maximum heights per transect; (3) canopy openness; (4) vertical profiles of leaf area density (LAD); (5) the fraction of the total leaf area index (LAI) contained in the highest 5m and in the highest 10m of the canopy and in the highest 6m and in highest 11m of the understory; and (6) the average LAI per transect and the LAI of each 1m horizontal interval, the latter used to construct frequency histograms. From the baser of the catena toward the plateau, top-of-canopy height and top-of-canopy roughness both increase. Vertical profiles of the leaf area density are bimodal in all four forest types, with higher concentrations of leaves in the lower understory and in the upper canopy. The upper canopy leaf density mode gradually decreases from the riparian forest toward the plateau, as expected from the increasingly irregular topof-canopy surface. The lower understory´s leaf density is greatest in the waterlogged riparian forest and lowest in the tall white-sand forest. The first 5m of upper canopy (below the highest return at each horizontal transect interval of 1m) contains 54-60% of the leaf area of the forest. The first 10m of upper canopy contain 79-86% of the leaf area. Canopy openness and the LAI (using six transect averages per forest type) do not vary between the four forest types. Over the full year, three significant changes in LAI were detected when all four forest types were lumped (repeated-measures analysis of the 24 transects per month). First, there was an LAI increase of 2.9% from 15/Mar to 15/Aug/2015 (wettest month to first dry month); then a drop of 2.0% from 15/Aug to 15/Oct (two driest months of the 2015 El Niño); and finally there was an LAI increase of 3.7% as precipitation gradually increased from 15/Oct/2015 to 15/Jan/2016. Over the full year (15/Mar/2015- 15/Mar/2016) there was a small but significant increase in the LAI (3% ± 2%). There was no seasonal change of the LAI in the understory (1 to 5/11m above the ground). When lumping all forest types, seasonal amplitude of LAI (between the smallest and largest of the 13 monthly averages) was only 4.8%, indicating that LAI alone should have little influence on the seasonality of the forest canopy photosynthetic capacity, even in a severe El Niño year. However, the frequency histograms of the LAI classes, obtained for 900 intervals of 1m from the six transects of each of the four forest types, had a truncated upper tail in every month, indicating saturation in the detectability of high values of LAI. Therefore, the seasonal variation of LAI was probably underestimated. Saturation may also impede detecting LAI differences between the forest typesO objetivo deste estudo foi investigar as diferenças estruturais do dossel e sua variação sazonal em quatro ambientes de terra firme na Amazônia Central. Foram obtidos atributos estruturais do dossel florestal, utilizando um LiDAR tipo rangefinder, que fornece a distância até o último retorno de cada pulso, na frequência de 1.000 pulsos por segundo. O sensor foi orientado para cima e mantido 1m acima do chão. Foram percorridos mensalmente, em velocidade constante, seis transectos de 150m em cada um de quatro ambientes florestais (total de 900m de transecto por tipologia). Do mais alto para o mais baixo na topossequência, estes foram: platô argiloso e bem drenado; vertente superior argiloso e bem drenado; vertente inferior com areia branca (campinarana); e faixa ripária sazonalmente encharcada sobre areia branca (baixio). O perfil de estrutura de cada transecto foi representado por uma nuvem bidimensional contendo a posição (x, z) de ~345.000 últimos retornos. Os principais atributos extraídos foram: (1) a altura máxima em cada intervalo de 1m horizontal; (2) a média e o desvio padrão (rugosidade) destas 150 alturas máximas por transecto; (3) a abertura do dossel; (4) perfis verticais da densidade de área foliar (LAD); (5) a fração do índice de área foliar (LAI) que é contida nos 5m e nos 10m de dossel superior e nos 6m e 11m de altura no sub-bosque; e (6) o LAI médio de cada transecto e de cada intervalo de 1m horizontal, este último para avaliar histogramas de frequência. Do ambiente ripário em direção ao platô, a altura e a rugosidade do dossel aumentam. O perfil vertical da densidade de área foliar mostrou-se bimodal em todos os ambientes, com uma concentração de folhas no subbosque e outra no dossel superior. A concentração das folhas em uma faixa específica de altura no dossel superior se atenua gradualmente do baixio para o platô, o que é consistente com o aumento de rugosidade. O sub-bosque é mais denso no baixio e menos denso na campinarana alta. Os primeiros 5m de dossel superior (abaixo do retorno mais alto em cada incremento horizontal de 1m) contêm 54-60% da área foliar da floresta. Os primeiros 10m de dossel superior contêm 79-86% da área foliar. A abertura do dossel e o LAI (médias por transecto de 150m) não variam entre os quatro ambientes. Ao longo do ano, ocorreram três mudanças significativas no LAI quando os ambientes foram analisados em conjunto. Primeiro, houve aumento de 2,9% de 15/Mar a 15/Ago/2015 (mês mais chuvoso até o primeiro mês seco); depois houve queda de 2,0% de 15/Ago a 15/Out/2015 (os meses mais secos do El Niño de 2015); e finalmente houve aumento de 3,7% durante a retomada das chuvas no período 15/Out/2015 a 15/Jan/2016. Entre março de 2015 e março de 2016 houve um aumento pequeno, mas significativo do LAI (3% ±2%). Não houve mudança sazonal do LAI no sub-bosque (1 a 6m e 1 a 11m do chão). O conjunto dos 24 transectos dos quatro ambientes, a amplitude temporal do LAI entre a menor e a maior das 13 médias mensais foi apenas 4,8%, indicando que o LAI, sozinho, teria pouca influência sobre a sazonalidade da capacidade fotossintética do dossel, mesmo neste ano de El Niño severo. O histograma de frequências de classes de LAI, obtido para os 900 intervalos de 1m ao longo dos seis transectos de cada ambiente, teve cauda superior truncada em todos os ambientes e todos os meses, indicando saturação na detectabilidade de valores altos de LAI. Portanto, a variação sazonal de LAI foi provavelmente subestimada. Esta saturação também pode impedir a detecção de diferenças LAI entre os ambientes