Gradiometria magnética e radar de penetração no solo aplicados em Estearias de Penalva (MA)

Nesse trabalho são apresentados os métodos geofísicos magnetometria e radar de penetração no solo (GPR) como ferramentas utilizadas na localização de vestígios de ocupações pretéritas no sítio arqueológico Lago da Lontra, localizado no município de Penalva, Estado do Maranhão. Devido à dimensão da área, de cerca de 10.400 m², e do curto período da campanha geofísica foram realizadas medidas magnéticas com gradiômetro em uma malha de amostragem de 2,5 m. As anomalias encontradas evidenciam uma magnetização termo-remanescente proveniente da queima da argila e também de fontes não relacionadas a materiais arqueológicos, tais como pedaços de arreios e ferraduras de montaria, pregos e anzóis, entre outros. Nos locais com magnetização anômala, foram realizados 14 perfis de GPR com uma antena blindada de 400 MHz com o objetivo de localizar e diferenciar com maior precisão as estruturas arqueológicas e as atuais. Os resultados apresentados neste trabalho possibilitaram a verificação e a avaliação da potencialidade de métodos geofísicos como ferramenta auxiliar em estudos arqueológicos, o que foi comprovado pelo sucesso nas indicações dos alvos e pelas posteriores escavações que mostraram a presença de fragmentos cerâmicos e carvão relacionados ao sítio arqueológico.In this work we present the geophysical methods magnetometry and ground penetrating radar (GPR) as tools used in finding traces of preterit occupations at the archaeological site of Otter Lake, located in the municipality of Penalva, state of Maranhão, Brazil. Because of the size of the area, of about 10,400 m², and the short geophysics campaign, magnetic measurements were performed with a gradiometer, in a sampling grid of 2.5 m. The anomalies found show a thermo-remnant magnetization from the burning of clayl, and also from sources not related to archaeological materials, such as pieces of tack and riding horseshoes, nails and hooks, among others. In locations with anomalous magnetization, 14 GPR profiles were obtained with a 400 MHz shielded antenna in order to locate and differentiate more precisely the archaeological and existing structures. The results presented in this work allowed the verification and evaluation of the potential of geophysical methods as an auxiliary tool in archaeological studies, which has been proven by the success of the indications of the targets and the subsequent excavations which revealed the presence of pottery fragments and coal related to the archaeological site

Didactic Sequence for Teaching Exponential Function

This paper presents a methodological proposal for the teaching of exponential function, resulting from the application of a didactic sequence involving exponential function, where evidence of learning and the consolidation and application of mathematical concepts in problem solving were identified and analyzed. The Didactic Engineering of Michèle Artigue (1988) was used as a research methodology. As theoretical contributions that guided and enabled the development of the research, we chose the use of Mathematical Investigation in the classroom; Didactic Sequence in the conception of Zabala (1999); the Articulated Units of Conceptual Reconstruction proposed by Cabral (2017) and assumptions of Vygotsky\u27s theory. A didactic sequence composed of five UARC\u27s was elaborated to work the exponential function, with a view to minimizing the difficulties naturally imposed by the content to be explained. Microgenetic analysis of verbal interactions between teacher and students was used to analyze the results of the application. The results show that the students participating in the experiment showed evidence of learning, recorded during the process, and began to have a good understanding of the concepts and properties related to the topic, in addition to a good performance in carrying out the activities, facts that corroborate the potential of the didactic sequence proposed herein

Gradiometria magnética e GPR aplicados à arqueologia em sítio estuarino em Penalva - MA

This research presents the results of the application of geophysical methods noninvasive, in order to indicate possible sites of deposition of materials in archaeological survey at a site located in the municipality of estuarine Penalva in the state of Maranhão. The methods used were Magnetometry and Ground Penetrating Radar (GPR). The magnetic measurements were used to indicate the locations for excavation. The GPR was used to confirm the anomalies generated by the magnetic method, providing fewer errors when the magnetic anomalies are not caused by archaeological features. Were 14 profiles performed GPR using an antenna 400 MHz and 1664 magnetic measurements using the magnetometer. During the archaeological survey conducted, based on the geophysical anomalies provided by the team led by archaeologists Deusdedit Carneiro Leite Filho and Luiz Fernando Tavares Marques made five excavations at the site, which allowed them to rescue several ceramic pieces. The results presented in this study allowed us to verify and evaluate the potential of geophysical prospecting method to assist in archaeological studies.CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível SuperiorEsta pesquisa apresenta os resultados da aplicação de métodos geofísicos não invasivos, visando a indicação de possíveis locais de deposição de materiais, no levantamento arqueológicos em um sítio estuarino localizado no município de Penalva, no estado do Maranhão. Os métodos utilizados foram Magnetometria e Radar de Penetração no Solo (GPR). As medidas magnéticas foram utilizadas para indicar os locais para escavação. O GPR foi utilizado para confirmar as anomalias geradas pelo método magnético, proporcionando a diminuição de erros quando as anomalias magnéticas não são provenientes de feições arqueológicas. Foram realizados 14 perfis de GPR, utilizando uma antena de 400 MHz e 1664 medidas magnéticas, utilizando o magnetômetro. Durante o levantamento arqueológico realizado, baseando-se nas anomalias fornecidas pela geofísica, a equipe liderada pelos arqueólogos Deusdédit Carneiro Leite Filho e Fernando Luiz Tavares Marques realizou cinco escavações no sítio, o que lhes permitiu o resgate de várias peças cerâmicas. Os resultados apresentados nesta pesquisa permitiram verificar e avaliar a potencialidade da prospecção geofísica como método auxiliar em estudos arqueológicos

Evaluation of the contamination of the subsurface and groundwater by monoaromatic hydrocarbons in an eastern Amazonian town in northern Brazil

Dean of Research and Graduate Studies - PROPESP/Federal University of Pará - UFPA (Brazil), Amazon Foundation for Studiesand Research - FAPESPA (Brazil).Federal University of Pará. Coastal Studies Institute. Laboratory of Cartography, Geoprocessing and Modeling. Bragança, PA, Brazil.Federal University of Pará. Coastal Studies Institute. Laboratory of Cartography, Geoprocessing and Modeling. Bragança, PA, Brazil.Federal Rural University of Amazonia - Parauapebas University Campus. Study Group in Geosciences, Engineering and Environment. Parauapebas, PA, Brazil.Ministério da Saúde. Secretaria de Ciência, Tecnologia, Inovação e Insumos Estratégicos. Instituto Evandro Chagas. Laboratório de Toxicologia. Ananindeua, PA, Brasil.Ministério da Saúde. Secretaria de Ciência, Tecnologia, Inovação e Insumos Estratégicos. Instituto Evandro Chagas. Laboratório de Toxicologia. Ananindeua, PA, Brasil.Federal Institute of Education, Science and Technology. Bragança, PA, Brazil.Federal University of Pará. Coastal Studies Institute. Laboratory of Cartography, Geoprocessing and Modeling. Bragança, PA, Brazil.The present study evaluated the contamination by monoaromatic hydrocarbons (BTEX: benzene, toluene, ethylbenzene, and xylene) of the subsurface of gas stations and adjacent residences in the Amazonian town of Bragança, in northern Brazil. We combined the ground penetrating radar (GPR) geophysical tool, to detect possible plumes of contamination by BTEX, with gas chromatography (GC) and mass spectrometry (MS), which were used to diagnose the presence of BTEX in water samples obtained from boreholes located within the study area. The GPR identifed low-amplitude refections in the vadose zone of two gas stations, whose attenuation near the surface was due to the low permittivity recorded in the radargrams, which may have been caused by the reduced permittivity of the hydrocarbons (gas vapor) in comparison with water. The GC–MS identifed benzene, toluene, ethylbenzene and/or xylene in 13 water samples (19.7% of the samples collected). Only three of the samples contained two contaminants, invariably toluene and xylene, whereas all the others contained only a single BTEX. Toluene and xylene were the BTEX compounds found most frequently in the samples. However, none of the samples collected in the study exceeded the threshold established by Brazilian legislation for BTEXs in drinking water. The integrated application of GPR and CG-MS produced satisfactory results for the diagnosis of the contamination of the subsurface of the gas stations surveyed in the present stud