Papers by Alexandre Navarro
Diálogos, 2017
A Arqueologia é associada, na maioria das vezes, à Pré-História e ao estudo do passado mais remot... more A Arqueologia é associada, na maioria das vezes, à Pré-História e ao estudo do passado mais remoto da Humanidade. No entanto, a Arqueologia estuda a cultura material, que é todo o artefato produzido pelo ser humano. Este artigo discute a possibilidade de uma Arqueologia do Rap, a partir da análise dos materiais utilizados em sua parafernália musical, sobretudo, o microfone. Neste caso, estes instrumentos são mediadores de ação social e também podem ser considerados cultura material.
Circular variables arise in a multitude of data-modelling contexts ranging from robotics to the s... more Circular variables arise in a multitude of data-modelling contexts ranging from robotics to the social sciences, but they have been largely overlooked by the machine learning community. This paper partially redresses this imbalance by extending some standard probabilistic modelling tools to the circular domain. First we introduce a new multivariate distribution over circular variables, called the multivariate Generalised von Mises (mGvM) distribution. This distribution can be constructed by restricting and renormalising a general multivariate Gaussian distribution to the unit hyper-torus. Previously proposed multivariate circular distributions are shown to be special cases of this construction. Second, we introduce a new probabilistic model for circular regression, that is inspired by Gaussian Processes, and a method for probabilistic principal component analysis with circular hidden variables. These models can leverage standard modelling tools (e.g. covariance functions and methods...
Encyclopedia of Global Archaeology
Regional Studies in Marine Science, 2021
This work describes the water circulation of Bahia Santa Elena using velocity fields and hydrogra... more This work describes the water circulation of Bahia Santa Elena using velocity fields and hydrographic data obtained from a ship-mounted Acoustic Doppler Current Profiler and a vertical profiler Conductivity–Temperature–Depth sonde, during two campaigns in August and October of 2019. Data were taken in a cross-bay transect in the main channel of the Bahia Santa Elena during a complete tidal cycle. The hydrographic data obtained during the two sampling campaigns suggest a reverse estuarine circulation; tidally averaged values of density and water velocities revealed a dense outflow at the bottom layer in the bay. This is the first description of an inverse estuary circulation pattern in Costa Rica and the second in Central America. Understanding the hydrographic properties of the bay is crucial for undertaking future research projects on water quality and biological communities.
Brasiliana: Journal for Brazilian Studies
Amazonian ethnography relies on a world created by an anaconda, an ancestral creator. The story t... more Amazonian ethnography relies on a world created by an anaconda, an ancestral creator. The story that myths tell is that the Amazon River is the metaphor of an anaconda; a large, meandering reptile. While the Anaconda sails along the great river, it populates the riverbanks, creating the Indian villages along its margins. This is why the anaconda is a snake-canoe. Amazonian societies are classified by archeology as belonging to the Polychrome Tradition of the Amazon (TPA). This research suggests that stilt villagers in eastern Amazonia, where shamanism played a role in communicating with animals, also shared this myth. The anaconda embodied in ceramic archaeological sites is as a memory of this complex indigenous narrative as it develops across time.
Water, 2021
In recent years, the northwestern part of the North Pacific areas of Costa Rica has undergone rap... more In recent years, the northwestern part of the North Pacific areas of Costa Rica has undergone rapid socioeconomic development. This situation, combined with the scarce available information about the water quality of the Gulf of Papagayo, became the starting point to carry out a study to investigate the spatiotemporal variations of physicochemical and biological parameters of surface waters. Seven samplings were collected during the dry season and the rainy season from October 2016 to February 2018. Water quality parameters such as: temperature, salinity, dissolved oxygen, and chlorophyll a of six analytes: nitrate, nitrite, ammonia, phosphate, silicate and biological oxygen demand were measured. The results showed that phosphate and ammonium levels were lower during the rainy season (<6 µg P-PO4−3 L−1–9.53 µg P-PO4−3 L−1 and <11 µg N-NH4+ L−1–9.57 µg N-NH4+ L−1) than during the dry season (<6 µg P-PO4−3 L−1–13.64 µg P-PO4−3 L−1 and <11 µg N-NH4+ L−1–14.43 µg N-NH4+ L−1)...
(Topic 6) Background. An increasing number of health-bots, able to perform diagnosis from a serie... more (Topic 6) Background. An increasing number of health-bots, able to perform diagnosis from a series of questions, are now available to patients. Active Medical Diagnosis describes the iterative process of hypothesis generation and hypothesis testing through which a model-based bot discovers the underlying cause of a patient’s altered state. It is an online process which requires planning of a sequence of questions or tests, and dynamic re-evaluation as new evidence is gathered. Information Gain (IG) is a classic measure to rank the best tests to conduct during Active Diagnosis [7, 8]. As compared to rule-based [6, 11], or reinforcement learning algorithms [1, 9, 4, 2], expert systems based on greedily maximizing the IG [3, 10] produce question sequences close to optimal [3] without expert-crafted policy and without loss of interpretability. However, such an algorithm relies solely on the probabilistic properties of the underlying model and is blind to semantic knowledge. As a result, in patient-facing tools for self-diagnosis, this method may produce sequences characterized by seemingly abrupt changes of context [8], producing poor user experience and affecting the patient’s trust in the system. Using a Bayesian Network (BN) crafted for medical diagnosis from case-history [5], we propose a method for embedding medical evidence over semantic simplices and compute a cost associated with changing contexts. Used in conjunction with greedy maximization, our approach allows clinicians and experts to tune the semantic consistency of question sequences without impacting the computational cost of the algorithm.
Este articulo explora uno de los resultados obtenidos en nuestra tesis de Doctorado que sedestino... more Este articulo explora uno de los resultados obtenidos en nuestra tesis de Doctorado que sedestino al estudio de la distribucion espacial de las serpientes emplumadas representadas enla iconografia de varios edificios del sitio arqueologico de Chichen Itza, Peninsula de Yucatan,Mexico. A traves de la catalogacion de imagenes se confirma que las serpientes emplumadasaparecen en contextos especificos y diferenciados en los dos principales sectores de la Gran Nivelacion del sitio en cuestion. PALABRAS-CLAVE: civilizacion maya, distribucion espacial, serpientes emplumadas, graficas,imagineria.
This article presents the preliminary results of research on the archaeological sites known as es... more This article presents the preliminary results of research on the archaeological sites known as estearias (pile dwellings), referring to piles (tree trunks) put inside the rivers for the construction of the villages in the precolonial period Lowland South America. The estearias studied are located in the south-eastern Amazon, in the present-day Brazilian state of Maranhão. Through analysis of colonial sources and material remnants, this article develops theoretical discussions about who were these peoples and why they inhabited the aquatic environment.
Background: Nowadays, many different techniques have been used to treat cranial cruciate ligament... more Background: Nowadays, many different techniques have been used to treat cranial cruciate ligament rupture (CrCL) in dogs, being the most common ones the tibial tuberosity advancement (TTA) and the tibial plateau leveling osteotomy (TPLO). These procedures promote dynamic stabilization. In other words, they try to stabilize the knee while supporting the limb, decreasing the cranial tibial impulse, which anticipates the function’s return. Among the complications observed in these kind of osteotomy, stand out the osteomyelitis, with 7,3% requency in TPLO and 6,6% in TTA. In these cases, it is necessary to remove all the implants. Most bone infections are from bacterial source, mostly caused by Staphylococcus genus. The aim of this study was to describe 14 cases of osteomyelitis in dogs after CrCL rupture corrective osteotomy. Materials, Methods & Results: This retrospective study evaluated 89 dogs (104 knees) that had undergone any of the CCLR corrective osteotomy during the period of ...
Circular variables arise in a multitude of data-modelling contexts ranging from robotics to the s... more Circular variables arise in a multitude of data-modelling contexts ranging from robotics to the social sciences, but they have been largely overlooked by the machine learning community. This paper partially redresses this imbalance by extending some standard probabilistic modelling tools to the circular domain. First we introduce a new multivariate distribution over circular variables, called the multivariate Generalised von Mises (mGvM) distribution. This distribution can be constructed by restricting and renormalising a general multivariate Gaussian distribution to the unit hyper-torus. Previously proposed multivariate circular distributions are shown to be special cases of this construction. Second, we introduce a new probabilistic model for circular regression, that is inspired by Gaussian Processes, and a method for probabilistic principal component analysis with circular hidden variables. These models can leverage standard modelling tools (e.g. covariance functions and methods...
Este artigo trata de apresentar o Codice de Dresden ao leitor e associa-lo com as representacoes ... more Este artigo trata de apresentar o Codice de Dresden ao leitor e associa-lo com as representacoes de Quetzalcoatl, uma importante divindade do Mexico pre-colonial. Propoe-se que um tema recorrente da referida fonte e o culto de Quetzalcoatl na sua manifestacao guerreira. Sugere-se que o Codice, apesar de ter sido confeccionado durante o Pos-Classico Tardio maia (1250-1525 d.C.), possui um contexto iconografico semelhando ao do Classico (300-800 d.C) o que indica uma continuidade cultural de costumes mais plasmada neste documento.
Este articulo tiene como objetivo presentar algunas evidencias materiales de la existencia de un ... more Este articulo tiene como objetivo presentar algunas evidencias materiales de la existencia de un culto guerrero enfocado en un personaje conocido en la arqueologia de Yucatan: Kukulcan. Primeramente se conceptua la guerra, luego se discute como el tema ha sido trabajado en la literatura cientifica, y, por fin, se analiza la evidencia de un culto guerrero a Kukulcan centrado en el sitio arqueologico de Chichen Itza, cuya actividad se desarrollo mas intensamente durante el Clasico Terminal, ca. 800-1050 d.C.
This article presents the initial results of a research project on "The People of the Waters... more This article presents the initial results of a research project on "The People of the Waters: Ar- chaeological Project about Dwellings on the North Central Portion at Baixada Maranhense." These results relate to the literature on the subject that we are studying, lifting some archaeological sites for excavation and questions about the process of prehistoric occupation in the study area. Keyboards: Archaeology. Prehistory of Maranhao. Dwellings. Settlement Pattern. Resumen: Este articulo presenta los resultados iniciales acerca del proyecto de investigacion "El Pueblo de las Aguas: carta arqueologica de los palafitos de la porcion centro norte de la Baixada Maranhense". Estos resultados dicen respecto al levantamento bibliografico para excavaciones y cuestionamientos acerca del proceso de ocupacion en el area de estudio. Palabras clave: Arqueologia. Pre-historia de Maranhao. Palafitos. Patron de asentamiento.
Quaternary Science Reviews
7600 years vegetation and environmental dynamics in coastal NE Brazil inferred from Lagoa do Form... more 7600 years vegetation and environmental dynamics in coastal NE Brazil inferred from Lagoa do Formoso. First detailed multi-proxy study including pollen, spore, charcoal, chemical and geochemical analysis in Maranhão State. Replacement of mangrove to terrestrial vegetation as consequence of sea-level oscillation and climate changes. Human influence on the environment during the late Holocene probably since the last 2600 years. See article on: https://authors.elsevier.com/c/1d~9d-4PR~R~2
Revista Eletrônica História em Reflexão
O presente artigo explora a Parte Segunda do volume I do Tesouro Descoberto no Máximo Rio Amazona... more O presente artigo explora a Parte Segunda do volume I do Tesouro Descoberto no Máximo Rio Amazonas, crônica escrita pelo jesuíta João Daniel durante os anos finais de sua vida, enquanto esteve preso em Portugal, após a expulsão dos jesuítas da América portuguesa. O texto, de invejável erudição, tanto mais por ter sido escrito de memória, relata todas as “maravilhas” vistas ou ouvidas pelo autor enquanto atuou como missionário no Estado do Maranhão em meados do século XVIII. A crônica combina uma descrição detalhista com uma visão complexa dos modos de vida dos índios. Por isso, discutimos a lógica da existência e das sociabilidades a partir dos elementos da cultura material mais frequentes na obra, a saber, das armas de guerra, instrumentos de casa (utensílios domésticos) e “brasões de nobreza”; observa-se ainda uma interessante contradição no discurso colonial do cronista.
Revista de Arqueologia
Os muiraquitãs são artefatos confeccionados, em geral, por nefrita verde, associados, especialmen... more Os muiraquitãs são artefatos confeccionados, em geral, por nefrita verde, associados, especialmente, às culturas arqueológicas das áreas de confluência dos rios Tapajós-Nhamundá-Trombetas. Estes objetos são vinculados à Tradição Inciso-Ponteada e aos falantes dos grupos Karib. Este artigo debruça-se nos dois muiraquitãs encontrados nas estearias do Lago Cajari, Baixada Maranhense, pelo geógrafo Raimundo Lopes entre 1919 e 1940, hoje desaparecidos por causa do incêndio que destruiu o Museu Nacional (RJ) em 2018. A partir da descrição tecnológica das peças, da análise simbólica e da evidência etno-histórica, conclui-se que os muiraquitãs das estearias foram importados do Baixo Amazonas, através de trocas entre grupos vizinhos, indicando uma circulação de bens de prestígio e certa interação social a partir do simbolismo destas pedras verdes.
Acta Hispanica, 2020
Este artículo presenta los resultados preliminares de una investigación sobre los sitios arqueoló... more Este artículo presenta los resultados preliminares de una investigación sobre los sitios arqueológicos conocidos en portugués como estearias, nombre que procede de los troncos de árboles colocados dentro de los ríos y usados para la construcción de aldeas en las tierras bajas de Sudamérica durante el periodo precolonial. Las estearias estudiadas están ubicadas en el sureste amazónico, en el actual Estado brasileño de Maranhão. A través del análisis de las fuentes coloniales y de los vestigios materiales, este artículo discute quiénes eran estos pueblos y por qué habitaban sobre el medio acuático. Palabras clave: cultura material, América precolombina, palafitos, etnohistoria. Abstract: This article presents the preliminary results of research on the archaeological sites known as estearias (pile dwellings), referring to piles (tree trunks) put inside the rivers for the construction of the villages in the precolonial period Lowland South America. The estearias studied are located in t...
Revista de Arqueologia, 2020
Os muiraquitãs são artefatos confeccionados, em geral, por nefrita verde, associados, especialmen... more Os muiraquitãs são artefatos confeccionados, em geral, por nefrita verde, associados, especialmente, às culturas arqueológicas das áreas de confluência dos rios Tapajós-Nhamundá-Trombetas. Estes objetos são vinculados à Tradição Inciso-Ponteada e aos falantes dos grupos Karib. Este artigo debruça-se nos dois muiraquitãs encontrados nas estearias do Lago Cajari, Baixada Maranhense, pelo geógrafo Raimundo Lopes entre 1919 e 1940, hoje desaparecidos por causa do incêndio que destruiu o Museu Nacional (RJ) em 2018. A partir da descrição tecnológica das peças, da análise simbólica e da evidência etno-histórica, conclui-se que os muiraquitãs das estearias foram importados do Baixo Amazonas, através de trocas entre grupos vizinhos, indicando uma circulação de bens de prestígio e certa interação social a partir do simbolismo destas pedras verdes.
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Papers by Alexandre Navarro