Regional gravity modelling and geohistory of the Parnaiba Basin (N.E. Brazil)

PhD ThesisThe Parn8.1ba Basin is one of the three large Palaeozoic intracratonic basins found in Brazil, the others being the Amazon and Parana. Parnaiba is an ovalshaped basin situated in NE Brazil and its area is about 600.000 km2 • Gravity data have been collected mainly along accessible roads crossing the Parn81ba Basin and merged with existing data bases of several Brazilian Institutions. The collection of all available geological and geophysical data included several gravity profiles crossing the eastern half of the basin. These profiles are part of a much larger data set forming polygons over a large proportion of the Brazilian territory. The whole gravity network has been internally adjusted and referred to the International Gravity Standardization Net 71. The net has been found precise to ±0.041 mGal. Although the distribution of gravity stations is not ideal, Bouguer and free-Air anomaly maps have been produced, these being the first gravity maps for the whole basin. Contrary to the basin physiography, the Bouguer map unexpectedly shows elongated gravity lows with NE-SW and NNW -SSE directions. These are parallel to the 'l'ransbrasiliano Lineament and subparallel to the Araguaia Fold Belt, respectively. A first attempt at interpreting the gravity anomalies resulted in the proposal of an anomalous, denser zone at lower crustal depths. The tectonic subsidence in the basinal area was estimated through systematic backstripping using 22 boreholes which reached the metamorphic or sedimentary basement. A non-uniform lithospheric stretching model was used as a first approximation for the modelling of the tectonic regime. This procedure was suggested by the presence of several grabenlike structures, as confirmed by shallow seismic sections, exploratory boreholes and gravity maps. Assuming an elastic rheology for the lithosphere, a regional W-E tectonic subsidence profile could be reproduced employing an axisymmetric subsurface load and a flexural ridigity of 0.2 x 1024 N m. Results of the present study are consistent with the apparent bimodality of the flexural ridigity of the continental lithosphere.The Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq): Overseas Research Student (ORS Award): The Departamento de Geofisica of the Observatorio Nacional, Rio de Janeiro

Factors driving the biogeochemical budget of the Amazon River and its statistical modelling Facteurs denext term contrôle du bilan biogéochimique previous termdenext term l'Amazone et modélisation statistique associée

International audienceThe seasonal and interannual fluctuations of the biogeochemical budget (solutes, suspended matter, isotopes) of the Amazon River basin were analyzed, with a special focus on 44 physicochemical parameters monitored over the period 1982-1984 during the Carbon in the AMazon River Experiment (CAMREX) project. The relevant factors driving this variability were identified and sorted through the implementation of a statistical-regressive model coupled to variance analysis. Basically, the compositional fluctuations in the Amazon River are related (1) to the variable contribution of major tributaries (variable regional source) to the river flow but also (2) to the variable contribution of hydrological sources, (3) to river processes, i.e. in-stream diagenesis and sediment dynamics and (4) to the hydrological budget of the floodplains. Their respective contributions to the variability of chemical signals observed in the stream waters depend on which parameter was investigated but their combination explains on average 85% of the observed variability. The variability related to regional sources was captured by the compared measures of flow discharge and biogeochemical fluxes at the outlet of the major tributaries. The variability of hydrological sources was described by the variable contribution of three runoffs of distinct but constant composition: forwarded direct runoff, delayed floodplain runoff and baseflow. Several methods were tested to depict the seasonal and interannual variations of their individual discharges. Biologically-mediated processes were related to a hydrobiological index IBIO = [O2]-[CO2] which allows tracking the nature of the dominant ecological regime (autotrophy vs. heterotrophy). The alteration of chemical signals related to the intermittent discharge of the floodplains (where specific processes occur such as: gas exchanges at the air-water interface, sorption of dissolved organic matter, chemical weathering, deposition vs. remobilization of sediments, etc.) was simulated by taking into account the default of hydrological balance between inflows and outflows, used as a marker of floodplains discharge. This analysis shows that the chemical baseline observed in the waters of the Amazon River is mostly acquired upstream from the junction of major tributaries with the Amazon main reach. Les fluctuations saisonnières et interannuelles du bilan biogéochimique (solutés, matière particulaire, isotopes) du fleuve Amazone ont été analysées, avec une attention particulière apportée à 44 paramètres physicochimiques mesurés entre 1982 et 1984 dans le cadre du programme CAMREX. Les facteurs exerçant une influence significative sur cette variabilité ont été identifiés et hiérarchisés par le biais d'un modèle statistique couplé à une analyse previous termdenext term variance. Les variations previous termdenext term composition des eaux previous termdenext term l'Amazone sont fondamentalement associées (1) à previous termlanext term contribution variable previous termdenext term ses affluents majeurs (source régionale variable) au débit total, mais aussi (2) à previous termlanext term contribution variable des pôles previous termdenext term mélange hydrologiques, (3) à des processus fluviaux correspondant au régime hydrobiologique et à previous termlanext term dynamique sédimentaire et (4) au bilan hydrologique des plaines d'inondation. Leurs contributions respectives à previous termlanext term variabilité des signaux chimiques observés dans les eaux du fleuve dépendent du paramètre considéré, mais leur combinaison explique en moyenne 85 % previous termde lanext term variabilité observée. previous termLanext term variabilité associée aux contributions régionales variables est appréhendée en procédant aux bilans entrées-sorties des débits et flux biogéochimiques. previous termLanext term variabilité previous termdenext term contribution des pôles previous termdenext term mélange est décrite par previous termlanext term contribution variable previous termdenext term trois écoulements previous termdenext term compositions distinctes mais constantes : l'écoulement direct à expression précoce, l'écoulement local previous termdenext term vidange alluviale à expression différée et l'écoulement previous termdenext term base. Douze méthodes ont été testées afin previous termdenext term décrire les variations saisonnières et interannuelles des débits individuels previous termdenext term chaque pôle previous termdenext term mélange. Les processus contrôlés par le vivant sont appréhendés à partir d'un indice hydrobiologique IBIO = [O2]-[CO2] qui permet previous termdenext term déterminer previous termlanext term nature du régime hydro-écologique dominant (autotrophe vs. hétérotrophe). L'altération des signaux chimiques générée par previous termlanext term vidange intermittente des plaines d'inondation (au niveau desquelles ont lieu des processus spécifiques : échanges gazeux, sorption previous termdenext term matière organique dissoute, érosion chimique, dépôt vs. remise en suspension previous termdenext term sédiments, etc.) est simulée en prenant en compte le défaut previous termdenext term bilan hydrologique entrées-sorties utilisé comme marqueur previous termdenext term débit des plaines d'inondation. Cette analyse montre que le bruit previous termdenext term fond chimique observé dans les eaux du fleuve Amazone est principalement acquis en amont des confluences entre le tronçon fluvial étudié et les principaux affluents qui l'alimentent

Biogeochemistry of the Amazonian Floodplains: Insights from Six End-Member Mixing Models

International audienceThe influence of Amazonian floodplains on the hydrological, sedimentary, and biogeochemical river budget was investigated along the Vargem Grande–Óbidos reach, by applying six mixing models based on variable regional and/or variable hydrological sources. By comparing the output of many different models designed for different purposes, the nature and the magnitude of processes linking water and biogeochemical budgets of the Amazonian floodplains were clarified. This study reveals that most of the chemical baseline of the Amazon River basin is acquired before the studied 2000-km Amazonian reach. However, the tight connection between the hydrograph stage of the river and the chemical signals provides insightful information on the dynamics of its floodplains. The chemical expression of biotic and abiotic processes occurring in the Amazonian floodplains can be particularly perceived during falling waters. It appears delayed in time compared to the maximum extension of submerged area, because the alternating water circulation polarity (filling versus emptying) between the main channel and the adjacent floodplains determines delayed emptying of floodplains during falling waters. It results also in a longer time of residence in the hydrograph network, which strengthens the rate of transformation of transiting materials and solutes. Biotic and biologically mediated processes tend to accentuate changes in river water chemistry initiated upstream, in each subbasin, along river corridors, indicating that processes operating downstream prolong those from upstream (e.g., floodplains of the large tributaries). Conversely, the flood wave propagation tends to lessen the seasonal variability as a result of the water storage in the floodplains, which admixes waters of distinct origins (in time and space). The morphology of floodplains, determining the deposition and the diagenesis of the sediments as well as the variable extension of submerged areas or the chronology of floodplains storage/emptying, appears to be the main factor controlling the floodplains biogeodynamics. By coupling classical end-member mixing models (providing insight on hydrological source) with a variable regional contribution scheme, relevant information on the biogeochemical budget of the Amazonian floodplains can be achieved

Comparação para o fator de atrito no dimensionamento de redes de distribuição utilizando equações explícitas / Comparison for the friction factor in distribution network sizing using explicit equations

Este trabalho tem o objetivo de analisar a influência de equações explícitas para o fator de atrito f da equação universal da perda de carga de Darcy-Weisbach no dimensionamento de redes de distribuição e identificar as equações que mais se aproximam da fórmula de Colebrook-White. A indicação preferencial do uso da equação Darcy-Weisbach para o cálculo da perda de carga no dimensionamento de redes, que, por sua vez, necessita da obtenção do fator de atrito f para o cálculo em cada trecho. A fórmula do fator de atrito de Colebrook-White é a equação mais representativa para a realidade da tubulação, mas é implícita para f. As equações explícitas são aproximações que tentam contornar este problema, mas, muitas vezes, são equações extensas e apresentam erros, o que as tornam opções pouco confiáveis. A análise da situação no dimensionamento de uma rede ramificada e uma rede malhada a partir de cada uma das metodologias de fator de atrito selecionadas apresentaram resultados que permitiram avaliar quais as melhores opções alternativas de equações explícitas para a fórmula implícita de Colebrook-White, de acordo com os valores obtidos do fator f, da perda de carga total das redes e das pressões disponíveis nos nós. Os resultados exibidos indicam que as equações de Sousa-Cunha-Marques e de Zigrang-Silvester apresentam uma maior aproximação a fórmula de Colebrook-White, enquanto que a equação de Swamee-Jain apresenta valores que mais se distancia das outras equações e, apesar disso, a diferença consiste na terceira e quarta casa decimal, o que não a torna inviável para utilização. 

Uso de resfriamento e congelamento para anestesia de cágados Phrynops geoffroanus (Pleurodira: Chelidae) e o estabelecimento da menor temperatura inicial letal

The use of hypothermia for anesthesia and euthanasia in ectothermic individuals has promoted many discussions, especially in the last four decades, and yet it continues today as a method that is prohibited or restricted to certain procedures. Despite this, some studies have shown satisfactory results in obtaining anesthetic plans, raising questions about the real possibility of using this method in research. The aim of the present experiment was to determine the time patterns to generate anesthesia and low incipient lethal temperature in Phrynops geoffroanus through cooling and freezing. Turtles reached the anesthesia grade nine within 30 minutes, making ease handling due to muscle relaxation, and, in 80 minutes, they reached anesthesia grade 11, becoming insensitive. The low incipient lethal temperature (LILT) shows that 1°C is the limit freezing from where the turtle can recover its motor activities while lower temperatures cause death. The low incipient lethal temperature was determined in a 300-minute period independently of the individual's size or weight.O uso de hipotermia para anestesia e eutanásia em indivíduos ectotérmicos tem gerado muitas discussões, especialmente nas últimas quatro décadas, e apesar disso continua hoje como um método que é proibido ou restrito a certos procedimentos.  Alguns estudos têm mostrado resultados satisfatórios na obtenção de planos anestésicos, levantando questionamentos sobre a real possibilidade do uso deste método em pesquisas.  O objetivo do presente experimento foi determinar o padrão de tempo de anestesia e da menor temperatura inicial letal através do resfriamento e congelamento em cágados da espécie Phrynops geoffroanus. Os cágados chegaram ao grau de anestesia nove em 30 minutos, tornando fácil seu manuseio devido ao relaxamento muscular e, em 80 minutos, alcançaram o grau 11 de anestesia tornando-se insensíveis. A menor temperatura inicial letal demonstrou que 1°C é o congelamento limite a partir do qual o cágado pode retomar sua atividade motora, sendo que temperaturas inferiores levam à morte. A menor temperatura inicial letal foi determinada em 300 minutos independentemente do tamanho ou peso do indivíduo

Peritoneopericardial Diaphragmatic Hernia in a Persian Cat

Background: Peritoneopericardial diaphragmatic hernia is a congenital defect characterized by an anomalous communication between the abdominal cavity and pericardial sac, which can lead to displacement of the abdominal viscera into the thoracic cavity. The occurrence in felines is higher among long-haired breeds, mainly the Persian breed, possibly based onan autosomal recessive inheritance. The diagnosis of PPDH is performed by means of chest radiography with or without contrast, in association with other imaging tests such as ultrasonography and echocardiography. Our objective in this study was to report the occurrence and macroscopic changes in a case of peritoneopericardial diaphragmatic hernia in a Persian feline. Case: A 9-year-old male Persian cat weighing 3.4 kg was referred to the HPET-Private Veterinary Clinic, Salvador, Bahia, with an history of weight loss and chronic intermittent vomiting during the preceding 6 months, with lateral decubitus and breathing difficulties. Ultrasonography revealed findings suggestive of an infiltrative process in the stomach and duodenum, enlarged gastric lymph nodes, and some nodular images indicating slight displacement of the liver. Chest radiography revealed a cardiac silhouette with markedly enlarged dimensions associated with a dorsal deviation of the terminal trachea, and echocardiography revealed a small amount of pericardial effusion. The patient showed initial clinical improvement after blood transfusion; however, after 2 days, he exhibited significant clinical worsening and was therefore euthanized with the owner's consent. Post mortem evaluation revealed partial herniation of the liver and gallbladder into the chest cavity through a diaphragmatic hernia ring. The heart was partially surrounded by the left medial lobe of the liver, which was displaced into the pericardial sac. Herniated hepatic lobes had an irregular capsular surface with evident lobulation and tension lipidosis. In the abdominal cavity, the remainder of the liver (right lateral and medial lobes) was observed to be slightly enlarged, with an irregular surface, diffusely reddish with intense evidence of the lobular pattern and white and firm multifocal areas (fibrosis). In the duodenum, close to the pylorus, there was a nodule measuring 2.8 x 2.5 x 1.0 cm, with a whitish and ulcerated surface. When cut, it was soft and exhibited a homogeneous, whitish compact surface.Histopathological examinationshowed marked proliferation of fibrous connective tissue, which for the most part separated the lobes by septa and surrounded the portal space (fibrosis), a marked diffuse chronic inflammatory infiltrate composed of lymphocytes and plasma cells. In addition, marked bile duct hyperplasia and multifocal areas of fatty degeneration (steatosis).Discussion: The diagnosis was based on the association of clinical and pathological findings. Considering the age and clinical signs presented by the patient in this report, as well as the presence of few radiographic signs that were indicative of PPDH, the first differential diagnosis thought was pericardial neoplasia. Peritoneopericardial diaphragmatic hernia in felines is always of congenital origin and may occur asymptomatically depending on the number and involvement of herniated viscera. In this case, the patient's diagnosis of peritoneopericardial hernia was a necropsy finding; the fact that in agreement with previous reports of high rates of incidental diagnoses reinforces the importance of performing necropsy for confirmation or diagnosis of unexpected pathologies. In the present case, peritoneopericardial diaphragmatic hernia in isolation may not have led to severe anemia that culminated in the patient's death. The anatomopathological findings were compatible with biliary cirrhosis and multifocal liver fibrosis, accompanied by the presence of anemia and consequent hypovolemia. Keywords: congenital diaphragmatic hernia, congenital abnormalities, cats. Título: Hérnia Diafragmática Peritoneopericárdica em um Felino da Raça PersaDescritores: hérnia diafragmática congênita, anomalias congênitas, felinos.

MORFOMETRIA CAUDA-CLOACAL PARA SEXAGEM DE Phrynops geoffroanus (SCHWEIGGER, 1812)

In order to study the presence of sexual dimorphism in Phrynops geoffroanus, collections were carried out in the Leite stream in the municipality of Floriano-Piauí. The 22 specimens captured (13 males e 9 female)  were measured and sexed, considering quantitative data (pre-cloacal and post-cloacal distances, length and width of the anal plate) and qualitative data (narrow or wide head and length of the humeral plates). Data were analyzed using the Wilcoxon-Mann-Whitney test (U), Dummy variable (D) and linear regression. The U Test demonstrated that the variables anal plate length (α = 0.177), pre-cloacal distance (α = 0.0004) and post-cloacal distance (α = 0.038) showed significant differences between genders. Through linear regression it was possible to observe that the pre-cloacal and post-cloacal length measurements in males have values twice as high as in females. The Dummy variable resulted in a value of D = 7.14, demonstrating that there is reason to believe in the existence of dimorphic morphological patterns in P. geoffroanus. From the results found, it is possible to conclude that the measurements of anal plate, pre-cloacal and post-cloacal distances are different between males and females in the studied population of P. geoffroanus, confirming sexual dimorphism, however, further studies of different populations are required in order to establish a morphological pattern for the species.Keywords: Morphology; Sexual dimorphism; Turtles.Com intuito de se estudar a presença de dimorfismo sexual em Phrynops geoffroanus, foram realizadas coletas no riacho do Leite no município de Floriano-Piauí. Os 22 espécimes capturados (13 machos e 9 fêmeas) foram biometrados e sexados, sendo considerados os dados quantitativos (distâncias pré cloacal e pós cloacal, comprimento e largura da placa anal) e qualitativos (cabeça estreita ou larga e comprimento das placas umerais). Os dados foram analisados através do teste de Wilcoxon-Mann-Whitney (U), variável de Dummy (D) e regressão linear. O Teste U demonstrou que as variáveis comprimento da placa anal (α= 0,177), distância pré cloacal (α= 0,0004) e pós cloacal (α= 0,038) apresentaram diferenças significativas entre os sexos. Através da regressão linear foi possível observar que as medidas de comprimento pré cloacal e pós cloacal nos machos possuem valores duas vezes maiores que nas fêmeas. A variável de Dummy resultou no valor de D = 7,14, demonstrando que existe razão em acreditar na existência de padrões morfológicos dimórficos em P. geoffroanus. A partir dos resultados encontrados, é possível concluir que as medidas comprimento da placa anal, distâncias pré cloacal e pós cloacal são diferentes entre machos e fêmeas na população de P. geoffroanus estudada, confirmando o dimorfismo sexual, porém, são necessários mais estudos de diferentes populações para que se estabeleça um padrão morfológico para a espécie.Palavras-chave: Dimorfismo sexual, Morfologia, Quelônios

A tomografia computadorizada de tórax como ferramenta auxiliar no diagnóstico de COVID-19 / Computed tomography of the chest as an auxiliary tool in the diagnosis of COVID-19

Objetivo: Avaliar a eficácia da Tomografia Computadorizada (TC) de tórax como ferramenta auxiliar no diagnóstico de COVID-19.Métodos: É um coorte realizado em pacientes com sintomas respiratórios compatíveis com SARS-CoV-2 que realizaram TC de tórax em uma clínica privada e, posteriormente, realizaram exames para COVID-19 entre 29 de abril de 2020 e 10 de maio de 2020. Dentre os 513 pacientes do estudo, apenas 132 participaram da casuística final por respeitarem os critérios de inclusão: pacientes maiores de 18 anos, assinatura do Termo de Consentimento Livre e Esclarecido, sob a suspeita de COVID-19. Foram excluídos aqueles que não realizaram exames comprobatórios ou não contactados pelos pesquisadores. Os pacientes foram contactados por via telefônica para coleta de idade, alterações pulmonares na TC e resultado do exame comprobatório realizado.Resultados: A casuística final foi de 132 pacientes (média de idade 47,8 ± 14,7 anos). A TC evidenciou o padrão em vidro fosco em até 25% do pulmão de 32,7% dos pacientes. O valor preditivo positivo dos intervalos percentuais de acometimento pulmonar (0-10%, 10-25%, 25-50%, 50-100%) foi de, respectivamente, 20%, 53,91%, 82,85%, 95,71%. Dos exames comprobatórios de COVID-19, o mais solicitado foi o Teste Rápido (52), o PCR (51) e as Sorologias pelo método ELISA (36). A positividade dos exames foi de: teste rápido em 67,31%; PCR em 82,25%; as sorologias em 86,11%.Conclusões: A TC de tórax pode ser uma ferramenta útil no diagnóstico de COVID-19 no Brasil. Porém, o resultado negativo não descarta o diagnóstico, necessitando de mais informações disponíveis

Estrutura e composição florística em área de floresta ombrófila densa sob manejo florestal

The purpose of this work is to deliver the phytosociology and floristicity of a fragment of Dense Ombrophilous Forest under forest management in the region of Portel, Pará. Four clusters were sampled, divided into secondary and terciarias plots totaling 80 sampling units of 0,4 hectares each. In which all tree individuals with diameter at breast height (DAP), at 1,30 m from ground level, above 10 cm were measured, in addition to performing phytothegic recognition and elaborating the calculations of the paramemers of equability and floristic similarity. A total of 1621 individuals were recorded, distributed in 35 families and 146 species. The families Fabaceae, Lecythidaceae and Sapotaceae were the ones with the highest IVIF and the highest representativeness of individuals. The species Eschweilera coriacea (DC.) S.A.Mori, Licania macrophylla Benth., Vouacapoua americana Aubl were the ones with the highest IVI. The mean Shannon variety index among the plots was 3,82 and the Pielou Equability index was 0,84, noting that the region has a high floristic variety and has great potential for forest management activities.O propósito do presente trabalho é determinar a fitossociologia e florística de um fragmento de Floresta Ombrófila Densa sob manejo florestal na região de Portel, Pará. Foram amostrados 4 conglomerados, divididos em parcelas secundárias e terciarias totalizando 80 unidades amostrais de 0,4 hectares cada. Nestas foram medidos todos os indivíduos arbóreos com diâmetro a altura do peito (DAP), a 1,30 m do nível do solo, acima de 10 cm além de determinar a fitossociologia e realizar os cálculos dos parâmetros de equabilidade e similaridade florística. Foram registrados 1621 indivíduos, distribuídos em 35 famílias e 146 espécies. As famílias Fabaceae, Lecythidaceae e Sapotaceae foram as que obtiveram os maiores índices do valor de importância familiar e a maior representatividade de indivíduos. As espécies Eschweilera coriacea, Licania macrophylla., Vouacapoua americana foram as que tiveram os maiores IVI. A média do índice de variedade de Shannon entre as parcelas foi de 3,82 e o da equabilidade de Pielou 0,84 constatando que a região apresenta alta diversidade florística além de apresentar grande potencialidade para as atividades do manejo florestal