Aplicação de técnicas de sensoriamento remoto na investigação do controle do posicionamento do Complexo Carbonatítico Seis Lagos e no estudo do depósito (Nb) laterítico associado (Amazonas, Brasil)

The main goals of this study were to identify geological structures that controlled the emplacement of the Seis Lagos Carbonatite Complex and contribute to the knowledge of the associated deposit, through the delimitation of the lateritic crust, the identification of internal structures and hydrothermal zones, where higher concentrations of Nb and REE may occur. Geophysical techniques, analysis of digital terrain elevation and processing techniques of orbital data were employed. The main regional structure has E-W direction and length of about 400 km. The positioning of the SLCC occurred where it is intersected by structures trending NE-SW and NW-SE. The boundaries of the lateritic crust are largely rectilinear, suggesting brittle structures, that may be the walls of the magma conduct, following open faults and fractures, or faults that affect the body after its crystallization. The main structures affecting the deposit have EW or NNW-SSE direction, controlled the formation of valleys and ridges, and karst processes with basin formation; therefore exerted role during laterization. Clayey zones likely related to hydrothermal processes were identified in four structures.Este estudo teve como objetivos principais identificar as estruturas geológicas que controlaram o posicionamento do Complexo Carbonatítico Seis Lagos, localizado no noroeste do Estado do Amazonas, e contribuir para o conhecimento da geologia do depósito associado, através da delimitação da crosta laterítica e identificação de estruturas internas e de zonas de alteração hidrotermal onde maiores concentrações de Nb e ETR podem ocorrer. Foram utilizados os métodos geofísicos aeromagnetometria, aerogamaespectometria e mapas de anomalia Bouger, análise de modelo digital de elevação e técnicas de processamento de dados orbitais. A principal estrutura regional tem direção geral E-W, extensão de cerca de 400 km. O posicionamento do CCSL ocorreu onde ela é intersectada por estruturas de direção NE-SW e NW-SE. Os limites da crosta laterítica são em grande parte retilíneos, sugerindo estruturas rúpteis, sejam estas as paredes do conduto magmático, aberto seguindo falhas e fraturas, ou falhas que afetaram o corpo após sua cristaliza- ção. As principais estruturas afetando o depósito têm direção E-W ou NNW-SSE, controlaram a formação de vales e cristas, a atuação de processos cársticos com formação de bacias; exerceram, portanto, papel relevante durante o processo de lateritização. Zonas ricas em argilas indicativas de alteração hidrotermal foram identificadas em quatro estruturas

Large expert-curated database for benchmarking document similarity detection in biomedical literature search

Document recommendation systems for locating relevant literature have mostly relied on methods developed a decade ago. This is largely due to the lack of a large offline gold-standard benchmark of relevant documents that cover a variety of research fields such that newly developed literature search techniques can be compared, improved and translated into practice. To overcome this bottleneck, we have established the RElevant LIterature SearcH consortium consisting of more than 1500 scientists from 84 countries, who have collectively annotated the relevance of over 180 000 PubMed-listed articles with regard to their respective seed (input) article/s. The majority of annotations were contributed by highly experienced, original authors of the seed articles. The collected data cover 76% of all unique PubMed Medical Subject Headings descriptors. No systematic biases were observed across different experience levels, research fields or time spent on annotations. More importantly, annotations of the same document pairs contributed by different scientists were highly concordant. We further show that the three representative baseline methods used to generate recommended articles for evaluation (Okapi Best Matching 25, Term Frequency-Inverse Document Frequency and PubMed Related Articles) had similar overall performances. Additionally, we found that these methods each tend to produce distinct collections of recommended articles, suggesting that a hybrid method may be required to completely capture all relevant articles. The established database server located at https://relishdb.ict.griffith.edu.au is freely available for the downloading of annotation data and the blind testing of new methods. We expect that this benchmark will be useful for stimulating the development of new powerful techniques for title and title/abstract-based search engines for relevant articles in biomedical research.Peer reviewe

Large expert-curated database for benchmarking document similarity detection in biomedical literature search

Document recommendation systems for locating relevant literature have mostly relied on methods developed a decade ago. This is largely due to the lack of a large offline gold-standard benchmark of relevant documents that cover a variety of research fields such that newly developed literature search techniques can be compared, improved and translated into practice. To overcome this bottleneck, we have established the RElevant LIterature SearcH consortium consisting of more than 1500 scientists from 84 countries, who have collectively annotated the relevance of over 180 000 PubMed-listed articles with regard to their respective seed (input) article/s. The majority of annotations were contributed by highly experienced, original authors of the seed articles. The collected data cover 76% of all unique PubMed Medical Subject Headings descriptors. No systematic biases were observed across different experience levels, research fields or time spent on annotations. More importantly, annotations of the same document pairs contributed by different scientists were highly concordant. We further show that the three representative baseline methods used to generate recommended articles for evaluation (Okapi Best Matching 25, Term Frequency-Inverse Document Frequency and PubMed Related Articles) had similar overall performances. Additionally, we found that these methods each tend to produce distinct collections of recommended articles, suggesting that a hybrid method may be required to completely capture all relevant articles. The established database server located at https://relishdb.ict.griffith.edu.au is freely available for the downloading of annotation data and the blind testing of new methods. We expect that this benchmark will be useful for stimulating the development of new powerful techniques for title and title/abstract-based search engines for relevant articles in biomedical science. © The Author(s) 2019. Published by Oxford University Press