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Journal articles on the topic 'Sonar de varredura lateral'
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Scottá, Fernando Comerlato, Mauro Michelena Andrade, Vicente Oliveira Silva Junior, Natacha Oliveira, Jair Weschenfelder, Eduardo Calixto Bortolin, and José Carlos Nunes. "GEOACOUSTIC PATTERNS OF THE GUAÍBA RIVER BOTTOM AND SUBBOTTOM AND THEIR RELATIONSHIP WITH SEDIMENTARY AND HYDRODYNAMIC PROCESSES." Brazilian Journal of Geophysics 37, no. 1 (March 27, 2019): 105. http://dx.doi.org/10.22564/rbgf.v37i1.1991.
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ABSTRACT. This work aimed at studying the bottom and sub-bottom geoacoustics of the Guaíba River, whose echo patterns are related to hydrodynamic patterns and sedimentary processes. A total of 324 km of seismic transects were surveyed using the Stratabox high-frequency (10 kHz) profiler with concomitant imaging using a side-scan sonar in the northern and central areas of the Guaíba system. The records were interpreted with the aid of complementary data (bathymetry and bottom samples), and maps containing the spatial arrangement of echo-characters were developed. The echo-characters were classified into seven different types according to the presence of sediments controlled by the hydrodynamics of the system or modified by human action. In general, the echoes related to the deposition of fine sediments occurred in deeper areas, the navigation channel or surrounding areas. The echoes in the shallower areas presented strong acoustic reflectivity at sites with lower deposition of fine sediments and predominance of sandy sediments. The occurrence and morphology of asymmetric subaqueous dunes indicated a predominant north-to-south flow and a river behavior.Keywords: shallow geophysics, sedimentology, hydrodynamics, geoprocessing.RESUMO. Este trabalho tem por objetivo o estudo geoacústico de fundo e subfundo do rio Guaíba, cujos padrões de ecos são relacionados aos padrões hidrodinâmicos e aos processos sedimentares atuantes. Foram levantados 324 km de perfis sísmicos em extensão, com o perfilador de alta frequência (10 kHz) Stratabox e concomitante imageamento com Sonar de Varredura Lateral nas áreas Norte e Central do Guaíba. Os registros foram interpretados com o auxílio de dados complementares (batimetria e amostras de fundo) e foram confeccionados mapas com a disposição espacial dos eco-caráteres. Os eco-caráteres foram classificados em sete diferentes tipos, de acordo com a presença de sedimentos controlados pela hidrodinâmica do sistema ou modificados pela ação humana. De uma forma geral, os ecos relacionados à deposição de sedimentos finos ocorrem nas áreas mais profundas, no canal de navegação ou adjacências. Os ecos nas áreas mais rasas apresentam forte refletividade acústica, em locais com menor deposição de sedimentos finos e predomínio de sedimentos arenosos. A ocorrência e morfologia de dunas subaquosas assimétricas indicam um fluxo preponderante no sentido Norte – Sul e um comportamento fluvial do sistema aquático.Palavras-chave: geofísica rasa, sedimentologia, hidrodinâmica, geoprocessamento.
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Cassou, Jean‐Pierre. "Device for processing modulated signals received by a lateral sonar system." Journal of the Acoustical Society of America 84, no. 2 (August 1988): 796. http://dx.doi.org/10.1121/1.396824.
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Burwen, Debby L., Steven J. Fleischman, James D. Miller, and Mark E. Jensen. "Time-based signal characteristics as predictors of fish size and species for a side-looking hydroacoustic application in a river." ICES Journal of Marine Science 60, no. 3 (January 1, 2003): 662–68. http://dx.doi.org/10.1016/s1054-3139(03)00054-7.
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Abstract Side-looking, fixed-location sonar is used to estimate the abundance of migrating chinook salmon Oncorhynchus tshawytscha in the Kenai River, Alaska. For this application, echo-envelope length has previously been shown to predict fish size better than target strength. Using tethered-fish experiments we generalize these findings to other hydroacoustic descriptors based on time measurements, including range-measurement variability and fish lateral movement. These variables are all descriptors of the echo signal through time. Measurements of these attributes were correlated with daily indices of the species composition of unrestrained fish passing the sonar site. We hypothesize that time-based characteristics are superior predictors of fish size because they capitalize on, or are robust to, the factors which compromise amplitude-based measurements with side-looking sonar.
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Pedersen, Geir, Nils Olav Handegard, and Egil Ona. "Lateral-aspect, target-strength measurements of in situ herring (Clupea harengus)." ICES Journal of Marine Science 66, no. 6 (May 8, 2009): 1191–96. http://dx.doi.org/10.1093/icesjms/fsp121.
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Abstract Pedersen, G., Handegard, N. O., and Ona, E. 2009. Lateral-aspect, target-strength measurements of in situ herring (Clupea harengus). – ICES Journal of Marine Science, 66: 1191–1196. Surveys of schooling herring with the new multibeam sonar (Simrad MS70) pose new challenges when converting the echo energy to estimates of biomass. Because the sonar projects horizontally, data and models of lateral-aspect, herring target strength (TS) are needed. In this study, the TS of herring is measured with a horizontally projecting, split-beam echosounder (Simrad EK60). Target-tracking methods are used to estimate swimming angles relative to the horizontal (θ) of individual herring within schools and layers and to evaluate how θ and TS change with depth (z). Measurements of θ and TS are used as inputs for a model describing TS as a function of θ and z. The results indicate that the mean lateral-aspect TS of in situ herring depends on z. Moreover, the mean lateral-aspect TS is more sensitive to z than the mean dorsal-aspect TS predicted by a published model. At z = 50 m, the mean lateral-aspect TS is nearly 2.5 dB higher than the mean dorsal-aspect TS. Conversely, at z = 350 m, the lateral-aspect TS is 5 dB lower. These results suggest that herring swimbladders do not compress uniformly with increasing pressure, but compress dorsoventrally more than laterally.
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Justino, Jeferson De Sousa, Matheus Dos Santos Andrade, Sterllany Vieira Dantas, and Seânia Santos Leal. "Efeito do laser GaAs em portadores de epicondilite lateral desencadeada por DORT." ConScientiae Saúde 13, no. 1 (March 28, 2014): 110–17. http://dx.doi.org/10.5585/conssaude.v13n1.4547.
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Objetivo: Verificar os efeitos da laserterapia de baixa intensidade (LBI) na dor e na funcionalidade do cotovelo. Método: A amostra, de caráter intencional, foi constituída de 12 pessoas distribuídas aleatoriamente em dois grupos, sendo: seis pessoas do grupo de intervenção (GI), que receberam a aplicação do LBI de 904 nm; e seis do grupo placebo (GP), que receberam a aplicação do LBI de 904 nm com o bico da caneta desligado. Realizaram-se sete aplicações do tipo varredura, com intervalo de 24 horas, utilizou-se a dosagem de 3 J/cm², com duração de 12 minutos e 30 segundos. Resultados: Houve redução da dor no GI (P=0,020) em comparação com a do GP (P=0,889), e a funcionalidade do cotovelo no GI aumentou (P=0,002), já no GP agravou-se (P=0,363). Conclusão: Infere-se, com base nos dados, que os efeitos da laserterapia de baixa intensidade são eficazes no tratamento da epicondilite lateral do cotovelo desencadeada por DORT.
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Fonseca, Erika Toledo da, Cláudia Marinovic de Oliveira, André Luís Rezende Franciolli, and Maria Angélica Miglino. "Características das papilas o dorso da língua de cabras (Capra hircus): estudo por de microscopia eletrônica de varredura e luz." Pesquisa Veterinária Brasileira 31, suppl 1 (December 2011): 67–73. http://dx.doi.org/10.1590/s0100-736x2011001300011.
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A morfologia das papilas linguais da cabra doméstica (Capra hircus) foi estudada por Microscopia Eletrônica de Varredura (MEV) e Microscopia de luz. Papilasfiiliformes, cônicas e lentiformes possuem função mecânica, enquanto que as papilas fungiformes e as valadas possuem função gustativa. As papilasfiiliformes estavam distribuídas por toda a extensão da língua, nas superfícies dorsal e lateral. Possuem um formato cônico com a extremidade pontiaguda direcionada caudalmente. Possuem vários processos secundários, de tamanhos diferentes, com a mesma orientação. A histologia revelou abundante tecido queratinizado. As papilas fungiformes foram observadas nas superfícies dorsal e lateral do ápice e do corpo da língua. Possuem formato semelhante a cogumelos, com epitélio corni[1]icado espesso e botões gustativos distribuídos na superfície. As papilas lentiformes se distribuíam na linha mediana da parte mais dorsal do toro, com projeções elevadas além da superfície da língua. Algumas apresentavam o formato de pirâmide e outras um formato mais achatado. As papilas valadas foram encontradas na superfície lateral da parte mais caudal do toro. Possuem formato arredondado, envolvido por um sulco pouco profundo. Possuem botões gustativos na parede lateral que se abrem no sulco. As papilas cônicas foram observadas no toro da língua e possuem formato alongado, com base larga e ponta romba. Embora as principais características morfológicas e estruturais do epitélio lingual sejam específicas da espécie, o tipo de alimentação e os hábitos alimentares podem influenciar na sua estrutura. Assim, o presente trabalho fornece uma descrição histológica e ultraestrutural da língua de cabras domésticas submetidas à alimentação baseada em gramíneas e ração.
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KAOURI, K., and D. J. ALLWRIGHT. "Determining the probability of correct resolution of the left–right ambiguity in towed array sonar." European Journal of Applied Mathematics 28, no. 5 (December 5, 2016): 716–35. http://dx.doi.org/10.1017/s0956792516000498.
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When a towed sonar array is straight, it has the difficulty that it cannot distinguish a contact on the left from one at the same angle on the right. When the array isnotstraight and its shape known, we calculate the probability that the left–right ambiguity is resolved correctly, using the Neyman–Pearson hypothesis testing framework, assuming a delay-sum beamformer, a single-frequency contact, and Gaussian noise. We also initially consider the noise field to be uncorrelated and show that the evaluation of the probability of correct resolution reduces to evaluating a one-dimensional integral. We find, as expected, that the probability increases, as the signal-to-noise ratio and the lateral deviation of the array from straight increase. For demonstration purposes, we also evaluate the probability of correct resolution for two representative shapes the array might assume in practice. Finally, we consider a more realistic, correlated noise field and we show that the initial assumption of an uncorrelated noise field provides a good approximation when the lateral deviation of the array is sufficiently large.
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Noviadi, Yogi, and Prijantono Astjario. "AKUMULASI TAILING DASAR LAUT DI PERAIRAN TELUK SENUNU DAN SEKITARNYA, SUMBAWA BARAT." JURNAL GEOLOGI KELAUTAN 9, no. 3 (February 16, 2016): 185. http://dx.doi.org/10.32693/jgk.9.3.2011.210.
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Teluk Senunu terletak di pantai selatan Kabupaten Sumbawa Barat, Provinsi Nusa Tenggara Barat. Daerah ini merupakan kawasan pembuangan tailing dari PT Newmont Nusa Tenggara (NNT). Hasil pemeruman di lokasi penyelidikan di sekitar alur pipa tailing memperlihatkan kedalaman dasar laut di sekitar Teluk Senunu bervariasi, pada kedalaman 0 sampai dengan 100 meter dijumpai pada jarak sekitar 3 - 3,25 km dari garis pantai. Keberadaan pipa tailing terluar berada pada kedalaman sekitar 120 meter dari permukaan dasar laut, dan posisi penempatan tailing ini terletak di kawasan Ngarai dengan kedalaman lebih dari 125 meter. Berdasarkan hasil penafsiran data Side Scan Sonar dijumpai adanya 3 jalur pipa tailing yang berada di permukaan dasar laut dengan penyebaran tailing secara lateral melebar sepanjang 1,5 km sejajar dengan tebing Ngarai Senunu.
Kata kunci : tailing, Teluk Senunu, Rekaman Seismik, Side scan sonar
Senunu bay is located on the southern coast of West Sumbawa Regency, West Nusa Tenggara. This area is a tailings disposal area of the ??PT Newmont Nusa Tenggara (NNT). Results of sounding around the tailing pipe shows the depth of the seafloor around the Senunu bay vary, at a depth of 0 to 100 meters was found at a distance of about 3 to 3.25 km from the coastline. The outer pipe of tailings located at a depth of 120 meters from the sealevel, and tailings placement position is located in the gap with a depth of more than 125 meters. Based on the results of Side Scan Sonar data interpretation, the 3 pipelines of tailings on the sea floor with spread laterally along the 1.5 km wide parallel to the canyon cliffs of Senunu.
Key words : tailing, Teluk Senunu, Seismic Record, Side scan sonar
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Parsons, Miles J. G., Iain M. Parnum, and Robert D. McCauley. "Visualizing Samsonfish (Seriola hippos) with a Reson 7125 Seabat multibeam sonar." ICES Journal of Marine Science 70, no. 3 (February 24, 2013): 665–74. http://dx.doi.org/10.1093/icesjms/fst009.
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Abstract Parsons, M. J. G., Parnum, I. M., and McCauley, R. D. 2013. Visualizing Samsonfish (Seriola hippos) with a Reson 7125 Seabat multibeam sonar – ICES Journal of Marine Science, 70: 665–674. In Western Australia, aggregations of Samsonfish (Seriola hippos) form each summer to spawn in waters west of Rottnest Island. In this study, a Reson 7125 Seabat multibeam sonar (400 kHz) was pole mounted aboard a 21.6 m vessel, conducting acoustic transects to acquire acoustic backscatter simultaneously from a midwater aggregation of S. hippos and the wreck it surrounded. The processed backscatter produced high-resolution visualizations of both the fish and seabed. During a 15 min period, the centroid of the aggregation moved 91 m around the eastern and northeastern side of the wreck and probably exhibited lateral vessel avoidance behaviour from the survey vessel. Additionally, a northeasterly current at the site was inferred from subtle habitat features, suggesting that at the time of the survey the aggregation preferred to remain upcurrent of the wreck. These findings confirmed that the S. hippos aggregations do not necessarily remain directly above the wrecks and do not always remain sedentary. Aggregation acoustic density packing at the survey site was observed at 12.7 ± 2.4 m3 per fish, equivalent to ∼1.6 ± 0.1 body lengths nearest-neighbour distance.
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Novák, Pavel, Radek Roub, Tomáš Hejduk, Tomáš Vybíral, Kateřina K. Hánová, and Filip Urban. "Comparison of the longitudinal and lateral profiles of watercourses using sonar-based methods (ADCP) and hydrological analogy." AUC GEOGRAPHICA 49, no. 2 (November 20, 2014): 111–19. http://dx.doi.org/10.14712/23361980.2014.20.
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Linxian, Liu, Zhang Wendong, Zhang Guojun, Guan Linggang, Xue Chenyang, Zhang Hui, and Xue Nan. "Research on double T-shape MEMS bionic vector hydrophone and its application in obstacle avoidance sonar." Sensor Review 35, no. 1 (January 19, 2015): 76–84. http://dx.doi.org/10.1108/sr-05-2014-642.
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Purpose – The purpose of this paper is to develop a novel MEMS vector hydrophone with the key features of smaller size, better consistency, higher sensitivity and directional reception, and to develop a highly effective and economical obstacle avoidance sonar system. Currently, the typical vector hydrophones are resonant vector hydrophones based on the accelerometer, which greatly increases the volume and constrains the detection sensitivity. Also, because the system is composed of a number of devices, its size is difficult to be reduced. Design/methodology/approach – A novel double T-shape MEMS vector hydrophone is proposed with a fish’s lateral line organs as prototypes. The structure size and layout location of the piezoresistors were determined by simulation analysis, and the double T-shape microstructure was fabricated integrally by MEMS manufacturing technology, after which, the acoustic package of the microstructure was completed and the prototype was produced. Finally, the packaged hydrophone was calibrated in a standing wave field in the first-class national-defense underwater acoustic calibration station of China. Also, the design and test of an obstacle avoidance sonar system based on the vector hydrophone were completed. Findings – The calibration data show that the double T-shape vector hydrophone has a flat frequency response curve, exhibits a sensitivity of −180 dB (1 kHz, 0 dB reference 1 V/uPa) and shows a good directivity pattern in the form of an “8” shape. The test results of the obstacle avoidance sonar system further verify the feasibility of detecting underwater acoustic signals. Research limitations/implications – The next work is to increase the sensitivity by optimizing the microstructure and to realize orientation by organizing array. Practical implications – The hydrophone has the advantages of smaller size, lower cost and directional reception. It can be used to develop highly effective and economical obstacle avoidance sonar system, thus solving the problems of water transport efficiency and traffic safety. The hydrophone has broad application prospects and a huge market potential in the civilian fields. Originality/value – The MEMS technology and innovative bionic microstructure enable the miniaturization and low cost of the hydrophone. The hydrophone is easy to form array and can narrow the array aperture greatly. So, the hydrophone can be widely used in civil sonar systems.
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Bourgeois, Aline, and Didier Jan. "Method of improving the restoration of images supplied by a lateral sonar and a device for implementing same." Journal of the Acoustical Society of America 83, no. 3 (March 1988): 1209–10. http://dx.doi.org/10.1121/1.396031.
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Ortiz-Velázquez, Rogelio Iván, José Guilherme Mendes Pereira Caldas, Patrícia Hatsue Suegama, Marina Magnani, Jorge Arturo Santos-Franco, Rodrigo Mercado-Pimentel, Leonardo Yuji Tanaka, and Maria Cecília Salvadori. "Microscopia de força atômica no estudo da superfície endotelial de bifurcações arteriais cerebrais humanas." Arquivos Brasileiros de Neurocirurgia: Brazilian Neurosurgery 28, no. 01 (March 2009): 01–08. http://dx.doi.org/10.1055/s-0038-1625547.
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Resumo Objetivo: Apresentar o estudo morfológico do endotélio vascular de artérias cerebrais humanas e discutir aplicações e limitações da microscopia de força atômica (AFM) no estudo da patologia vascular. Material e métodos: Foram utilizadas amostras do segmento M1 e da bifurcação da artéria cerebral média, com e sem doença aterosclerótica. Imagens topográficas, obtidas por microscopia eletrônica de varredura (MEV), das amostras fixadas quimicamente e desidratadas mediante ponto crítico foram confrontadas com imagens de amostras não fixadas, obtidas por AFM. Resultados: As células endoteliais nos segmentos retos de M1 e da bifurcação da ACM, sem doença aterosclerótica, são alongadas e alinhadas com o eixo axial do vaso, porém poligonais e sem orientação preferencial na bifurcação aterosclerótica. A bifurcação com aterosclerose apresenta uma monocamada endotelial altamente irregular e corrugada que invagina na luz do vaso e mostra características heterogêneas na superfície da membrana. A resolução das imagens de MEV foi superior àquela obtida nas imagens de AFM a baixa magnificação. Nas imagens de AFM, a parte lateral e as uniões celulares são pouco definidas e a varredura em altas magnificações diminui a resolução. Contudo, é possível determinar a topografia tridimensional da superfície celular, podendo-se, ao mesmo tempo, realizar estudos funcionais. Conclusão: Apesar da combinação única de alta resolução de imagem e operação sob condições próximas às fisiológicas, a AFM em amostras flexíveis apresenta resolução que depende do tipo de cantilever e do grau de hidratação da amostra. Por isso, em amostras vasculares as condições fisiológicas terão de ser estritamente reproduzidas.
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Li, Nansong, Minghui Zhang, and Bo Gao. "Horizontal Correlation of Long-Range Bottom Reverberation in Shallow Sloping Seabed." Journal of Marine Science and Engineering 9, no. 4 (April 13, 2021): 414. http://dx.doi.org/10.3390/jmse9040414.
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The performance of active sonar detection systems is seriously affected by the reverberation at the bottom of the waveguide in shallow water. In order to improve the performance of active sonar detection, it is necessary to understand the horizontal correlation of shallow-water bottom reverberation in active towed-array processing technology. However, the current research on the spatial correlation of reverberation is mainly based on vertical correlation, little work has been done on the horizontal correlation characteristics of long-distance seabed reverberation, and there is no support from sea test data. In this paper, the coupled mode reverberation model is applied to the horizontal correlation, and is studied according to the receiving position, time, and frequency. The simulation results show that, for the long-range bottom reverberation, the lateral correlation is greater than the longitudinal correlation in the horizontal space. By introducing the adiabatic mode solution, the mathematical model of horizontal correlation in the range-dependent waveguide with depth is derived. The numerical results show that the influence of the seabed dip angle on the horizontal correlation should be considered and that the horizontal correlation is affected obviously by the propagation effects of the sloped sea floor. Finally, the experimental data processing and analysis are given and verify the correctness of the algorithm.
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Fernandez, Vicente I., Audrey Maertens, Frank M. Yaul, Jason Dahl, Jeffrey H. Lang, and Michael S. Triantafyllou. "Lateral-Line-Inspired Sensor Arrays for Navigation and Object Identification." Marine Technology Society Journal 45, no. 4 (July 1, 2011): 130–46. http://dx.doi.org/10.4031/mtsj.45.4.20.
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AbstractThe lateral line is a critical component of fish sensory systems, found to affect numerous aspects of behavior, including maneuvering in complex fluid environments with poor visibility. This sensory organ has no analog in modern ocean vehicles, despite its utility and ubiquity in nature, and could fill the gap left by sonar and vision systems in turbid, cluttered environments.To emulate the lateral line and characterize its object-tracking and shape recognition capabilities, a linear array of pressure sensors is used along with analytic models of the fluid in order to determine position, shape, and size of various objects in both passive and active sensing schemes. We find that based on pressure information, tracking a moving cylinder can be effectively achieved via a particle filter. Using principal component analysis, we are also able to reliably distinguish between cylinders of different cross section and identify the critical flow signature information that leads to the shape identification. In a second application, we employ pressure measurements on an artificial fish and an unscented Kalman filter to successfully identify the shape of an arbitrary static cylinder.Based on the experiments, we conclude that a linear pressure sensor array for identifying small objects should have a sensor-to-sensor spacing of less than 0.03 (relative to the length of the sensing body) and resolve pressure differences of at least 10 Pa. These criteria are used in the development of an artificial lateral line adaptable to the curved hull of an underwater vehicle, employing conductive polymer technologies to form a flexible array of small pressure sensors.
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Berne, S., J. M. Augustin, F. Braud, G. Chene, and P. Walker. "Cartographie et interpretation de la dynamique sedimentaire des plates-formes continentales; ameliorations de la technique d'observation par sonar lateral." Bulletin de la Société Géologique de France II, no. 3 (May 1, 1986): 437–46. http://dx.doi.org/10.2113/gssgfbull.ii.3.437.
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Ricaurte, Constanza, Juan Gabriel Domínguez, Gisela Mayo, Carlos Alberto Andrade, Hernán Mauricio Ospina, and Alfredo De Jesús Gutiérrez. "Nota sobre algunos rasgos geomorfológicos de los Bancos de Salmedina." Boletín Científico CIOH, no. 22 (December 1, 2004): 64–76. http://dx.doi.org/10.26640/22159045.129.
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Se describen rasgos geomorfológicos de los Bancos de Salmedina mediante el análisis de la batimetría, videotransectos georeferenciados e imágenes de ecosonda multihaz en modo de 2 sonar lateral. La zona estudiada tiene un área total de 10.5 km de 2 los cuales 4 km correspondieron a las zonas propiamente 2 arrecifales y 0.45 km a lodos finos y lodolitos de origen diapírico. Los Bancos están compuestos por 5 elevaciones que corresponden a: Salmedina, Burbujas, Ygio, Kubina y Ukura. La geomorfología de estas formaciones se encuentra determinada por la influencia del oleaje predominante del noroeste, la actividad diapírica, muy reciente en el Banco Burbujas, representada en la aparente presencia de cráteres, grietas profundas y emanaciones de gas.
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Tenningen, Maria, Gavin J. Macaulay, Guillaume Rieucau, Héctor Peña, and Rolf J. Korneliussen. "Behaviours of Atlantic herring and mackerel in a purse-seine net, observed using multibeam sonar." ICES Journal of Marine Science 74, no. 1 (October 6, 2016): 359–68. http://dx.doi.org/10.1093/icesjms/fsw159.
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To ensure efficient and sustainable purse-seine fisheries, the catch process must be monitored to better understand the reactions of fish to the gear. In this study, we monitored the behaviours of herring (Clupea harengus) and mackerel (Scomber scombrus) schools during purse-seine capture using a multibeam imaging sonar (Simrad MS70, 75–112 kHz) mounted on a research vessel. The fish behaviours differed between species and purse-seine sets. For both species, the acoustic volume backscattering coefficient increased as 0–80% of the seine was hauled aboard, indicating a corresponding increase in fish spatial density. This increase was significantly greater for herring than mackerel. As 0–40% of the seine was hauled aboard the fishing vessel, schools changed their spatial distribution and volume independent of seine hauling, while for some schools, depth and height decreased. The acoustic volume backscattering strength was up to 25 dB higher in the centre of the school than in the edges. The average lateral target strength was estimated for individual fish in the captured herring schools, and the effect of incident angle on the backscattering strength is considered.
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Xie, Yunbo, Catherine G. J. Michielsens, Andrew P. Gray, Fiona J. Martens, and Jacqueline L. Boffey. "Observations of avoidance reactions of migrating salmon to a mobile survey vessel in a riverine environment." Canadian Journal of Fisheries and Aquatic Sciences 65, no. 10 (October 2008): 2178–90. http://dx.doi.org/10.1139/f08-128.
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Detailed avoidance reactions of adult migrating salmon to a mobile survey vessel were successfully observed with side-looking dual-frequency identification sonar (DIDSON) in the lower Fraser River (British Columbia, Canada). Both adult sockeye ( Oncorhynchus nerka ) and pink salmon ( Oncorhynchus gorbuscha ) returning to the river were found to avoid the approaching vessel by initiating lateral movements away from the vessel, making the fish unlikely to be insonified by the downward-looking transducers towed by the vessel. The vessel was found to have an estimated mean interference range of 4 m from its propeller. Analyses of the data concluded that once the vessel and fish were separated by more than 7 m, the vessel no longer affected the normal migration behaviour of the fish.
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Dias, Gilberto Tavares de Macedo, Luiz Henrique P. Fontana, Cleverson Guizan Silva, Rafael Cuellar de Oliveira e. Silva, Uirá Cavalcanti Oliveira, Leonardo da Silva Lima, José Antônio Baptista Neto, and Estefan Monteiro da Fonseca. "GEOMORPHIC AND SEDIMENTARY IMPACTS ON THE CONTINENTAL SHELFAFTER ACCUMULATED DREDGE DISPOSAL FROM RIO DE JANEIRO HARBOR, BRAZIL." Brazilian Journal of Geophysics 37, no. 4 (December 1, 2019): 515. http://dx.doi.org/10.22564/rbgf.v37i4.2024.
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ABSTRACT.Marine dredging is a subaquatic excavation activity executed around the globe for various purposes by many industries. The negative impacts ofdredged material discharge on benthic ecosystems are diverse. Researches on the results of dredging on estuarine geomorphology and its sedimentary regime areusual. Still, the results of dumping dredged material off the coast, in the Brazilian continental shelf, are not easily found in the literature. The present research evaluatedthe geomorphic disturbance resulted from discharging dredged material from Rio de Janeiro Harbor in the inner Rio de Janeiro continental shelf. Grain size analysisof the dredged and dumped sediments was compared to the inner shelf original seabed sediments. The geomorphological impact was evaluated through bathymetricand high resolution seismic and side scan sonar imagery methods. Obtained data revealed significant geomorphologic changes on the offshore bottom caused by theaccumulation of compacted mud from the dredge site underlying the recent soft mud bottom of the harbor area. Besides the morphological sea bottom disturbance,sediment accumulation, and local grain size characteristics exhibited significant change, potentially impacting the surrounding benthic environment.Keywords: Guanabara Bay, seafloor geomorphology, marine sediments, marine pollution.RESUMO.A dragagem marinha é uma atividade de escavação subaquática executada em todo o mundo por muitas indústrias para diferentes fins. Os impactosnegativos do descarte de material dragado nos ecossistemas bentônicos são diversos. Pesquisas sobre os resultados da dragagem na geomorfologia estuarina e o seuregime sedimentar são frequentes. Ainda assim, os resultados do despejo de material dragado ao longo da costa, na plataforma continental brasileira, não são facilmenteencontrados na literatura. A presente pesquisa avaliou o distúrbio geomórfico resultante do descarte de material dragado do Porto do Rio de Janeiro na plataformacontinental interna do Rio de Janeiro. A granulometria dos sedimentos dragados e descartados foi comparada com os sedimentos originais do fundo marinho naplataforma interna. O impacto geomorfológico foi avaliado através de métodos batimétricos, sísmica de alta resolução e imageamento por sonar de varredura lateral.Os dados obtidos revelaram mudanças geomorfológicas significativas no fundo causadas pelo acúmulo de lama compactada do local dragado, subjacente ao fundode lama mole recente da área do porto. Além do distúrbio morfológico do fundo marinho, o acúmulo de sedimentos e as características locais de tamanho de grãoapresentaram mudança significativa, potencialmente impactando o ambiente bentônico circundante.Palavras-chave: Baía de Guanabara, geomorfologia submarina, sedimentos marinhos, poluição marinha.
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Bocage, Ana Luiza Du, Mariana Albuquerque de Souza, Silvia Teresinha Sfoggia Miotto, and Vania Gonçalves-Esteves. "PALINOTAXONOMIA DE ESPÉCIES DE ACACIA (LEGUMINOSAE-MIMOSOIDEAE) NO SEMI-ÁRIDO BRASILEIRO." Rodriguésia 59, no. 3 (July 2008): 587–96. http://dx.doi.org/10.1590/2175-7860200859312.
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RESUMO (Palinotaxonomia de espécies do gênero Acacia (Leguminosae-Mimosoideae) no semi-árido brasileiro) Foi realizado o estudo palinológico de 12 espécies de Acacia: A. farnesiana (Acacia subg. Acacia) e A. bahiensis, A. globosa, A. kallunkiae, A. langsdorffii, A. martiusiana, A. monacantha, A. piauhiensis, A. polyphylla, A. riparia, A. tenuifolia e A. velutina (Acacia subg. Aculeiferum). Os grãos de pólen foram acetolisados, medidos, descritos e ilustrados sob microscópio de luz e eletrônico de varredura. Os grãos de pólen em Acacia são reunidos em políades calimadas, médias ou grandes, de contorno esferoidal, em vista frontal e elíptico, em vista lateral, com 16 grãos de pólen, organizados de forma regular, com oito grãos de pólen em cada face, 4-porados. Em A. farnesiana, são observados 24-32 grãos de pólen organizados de forma irregular, 3-sulcados. Os grãos de pólen da políade são pequenos, subquadrados na face distal e piramidal, quando em vista equatorial. A sexina é granulada ou rugulada, na maioria das espécies. Conclui-se que as espécies não podem ser separadas através das suas características palinológicas, com exceção de A. farnesiana.
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Peterson, Diana Coomes, Kiran Nataraj, and Jeffrey Wenstrup. "Glycinergic Inhibition Creates a Form of Auditory Spectral Integration in Nuclei of the Lateral Lemniscus." Journal of Neurophysiology 102, no. 2 (August 2009): 1004–16. http://dx.doi.org/10.1152/jn.00040.2009.
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For analyses of complex sounds, many neurons integrate information across different spectral elements via suppressive effects that are distant from the neurons' excitatory tuning. In the mustached bat, suppression evoked by sounds within the first sonar harmonic (23–30 kHz) or in the subsonar band (<23 kHz) alters responsiveness to the higher best frequencies of many neurons. This study examined features and mechanisms associated with low-frequency (LF) suppression among neurons of the lateral lemniscal nuclei (NLL). We obtained extracellular recordings from neurons in the intermediate and ventral nuclei of the lateral lemniscus, observing different forms of LF suppression related to the two above-cited frequency bands. To understand the mechanisms underlying this suppression in NLL neurons, we examined the roles of glycinergic and GABAergic input through local microiontophoretic application of strychnine, an antagonist to glycine receptors (GlyRs), or bicuculline, an antagonist to γ-aminobutyric acid type A receptors (GABAARs). With blockade of GABAARs, neurons showed an increase in firing rate to best frequency (BF) and/or LF tones but retained LF suppression of BF sounds. For neurons that displayed LF suppression tuned to 23–30 kHz, the suppression was eliminated or nearly eliminated by GlyR blockade. In contrast, GABAAR blockade did not eliminate nor had any consistent effect on suppression tuned to these frequencies. We conclude that LF suppression tuned in the 23- to 30-kHz range results from neuronal inhibition within the NLL via glycinergic inputs. For neurons displaying suppression tuned <23 kHz, neither GlyR nor GABAR blockade altered LF suppression. We conclude that such suppression originates at a lower auditory level, perhaps a result of cochlear mechanisms. These findings demonstrate that neuronal interactions within NLL create a particular form of LF suppression that contributes to the analysis of complex acoustic signals.
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Silva, Iran José Oliveira da, Helen Jamil Khoury, Márcia Rosana Leite de Lemos, Paulo José de Almeida Filho, and Maria Inês Calil Cury Guimarães. "Estudo do efeito do uso de colimador na sonda gama utilizada em cirurgia radioguiada." Radiologia Brasileira 39, no. 6 (December 2006): 429–34. http://dx.doi.org/10.1590/s0100-39842006000600011.
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OBJETIVO: O objetivo deste trabalho consiste em estudar a influência da resolução espacial da sonda gama Europrobe que é utilizada em cirurgia radioguiada. MATERIAIS E MÉTODOS: Na técnica de cirurgia radioguiada, após a injeção de um radiotraçador no tumor primário, é utilizada uma sonda detectora de radiação gama a fim de determinar a localização do linfonodo sentinela. Para simular a região dos pontos de injeção do radiotraçador e o linfonodo sentinela, duas fontes de Tc-99m, com 20,42 MBq e 0,70 MBq, foram posicionadas no interior de um recipiente preenchido com água. Em seguida, com a janela de entrada da sonda coberta com um colimador, realizou-se varredura sobre a superfície da água. Assim, foi possível registrar a taxa de contagens variando-se a distância lateral da sonda em relação às duas fontes, as quais foram separadas por uma distância variando entre 30 mm e 60 mm. RESULTADOS: Os resultados mostraram que o uso do colimador contribui para melhorar a resolução espacial da sonda, permitindo a identificação do linfonodo sentinela distante até 30 mm do ponto de injeção. CONCLUSÃO: Esse estudo permite concluir que a sonda Europrobe, quando utilizada com capa colimadora com orifício central de 3,5 mm de diâmetro, é capaz de identificar o linfonodo sentinela posicionado a até 30 mm de distância em relação à região do ponto de injeção do radiotraçador.
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Patel, Ruben, and Egil Ona. "Measuring herring densities with one real and several phantom research vessels." ICES Journal of Marine Science 66, no. 6 (May 8, 2009): 1264–69. http://dx.doi.org/10.1093/icesjms/fsp128.
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Abstract Patel, R., and Ona, E. 2009. Measuring herring densities with one real and several phantom research vessels. – ICES Journal of Marine Science 66: 1264–1269. Vessel-induced avoidance can potentially cause a large bias in acoustic estimates of schooling, pelagic-fish biomass. This paper presents a method for quantifying this uncertainty. Volume-backscattering strength (Sv) from a horizontally projecting, multibeam sonar (Simrad MS70) is resampled to form synthetic, vertical, echosounder beams to the side of the survey vessel. These data are analysed as if they were collected from phantom vessels surveying parallel transects at fixed ranges from the real vessel. The nautical-area-backscattering coefficients (sA) from the synthetic echograms are compared with those measured by conventional 70 and 120 kHz echosounders (Simrad EK60) on the real vessel. Data collected in 2006 from schools of Norwegian spring-spawning herring are used to illustrate the method and explore its limitations. Potential effects of vessel-induced avoidance are evaluated by comparing the mean sA values observed from the phantom vessels with those observed from the real vessel. The technique also allows direct estimates of the mean lateral-aspect target strength of in situ herring.
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Santos-Mallet, Jacenir Reis dos, Margareth Cardozo-de-Almeida, Shenia Corrêa Novo, and Teresa Cristina Monte Gonçalves. "Morfologia Externa de Triatoma carcavalloi Jurberg, Rocha & Lent (Hemiptera: Reduviidae: Triatominae) Através da Microscopia Ótica e Microscopia Eletrônica de Varredura." EntomoBrasilis 1, no. 2 (July 23, 2008): 37–42. http://dx.doi.org/10.12741/ebrasilis.v1i2.28.
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Resumo. Triatoma carcavalloi Jurberg, Rocha & Lent é uma espécie com distribuição geográfica restrita ao Estado do Rio Grande do Sul, hábitos silvestres, vivendo em simpatria com Triatoma rubrovaria (Blanchard) e Triatoma circummaculata (Stal). Diferenças morfo-estruturais na região cefálica de adultos foram ilustradas. Na análise morfológica das antenas de T. carcavalloi foi verificado em machos e fêmeas a ocorrência de 14 tricobótrias no terceiro e quarto segmento antenal. Na cabeça a presença de 1+1 manchas pós-ocelares. Nos fêmures das pernas de ambos os sexos foi encontrado um par muito pequeno de dentículos subapicais. As fossetas esponjosas foram encontradas somente nos machos, nas tíbias das pernas anteriores e medianas. O estudo do rostro é importante para a caracterização da subfamília Triatominae, assim como o sulco estridulatório e a búcula. A búcula possui borda grossa, superfície granular e forma de “U”. O rostro é similar em ambos os sexos. A placa apical tem forma de diamante na lamela inferior e forma digitiforme na lamela superior. No ápice do rostro duas fendas laterais 1+1 foram observadas. O sulco estridulatório desta espécie tem a forma de "V" e é mais largo nas fêmeas do que nos machos. Esta é a primeira descrição morfológica destas estruturas em adultos de T. carcavalloi usando a microscopia eletrônica de varredura. Estes resultados relacionados aos estudos morfológicos realizados em T. carcavalloi evidenciam a importância destas estruturas para caracterização específica.
External Morphology of Triatoma carcavalloi Jurberg, Rocha & Lent (Hemiptera: Reduviidae: Triatominae) by Optical and Scanning Electron Microscopy
Abstract. Triatoma carcavalloi Jurberg, Rocha & Lent is specie with restricted geographic distribution to the State of Rio Grande do Sul, rupestrial habits, living currently in simpatry with Triatoma rubrovaria (Blanchard) and Triatoma circummaculata (Stal). Morpho-structural differences in the cephalic region of the adults had also been illustrated. In the morphological analysis of the antennas of T. carcavalloi it was verified the occurrence in both, male and females, more than 14 trichobotrium, in the third and fourth antennal articles. In the head the presence of 1+1 post-ocelares spots. In the legs, a pair of sub-apical dentices in femures of both male and female was found. Spongy fossette had been found only in the males, in the tibias of the previous and medium legs. The study of rostrum is important to the characterization of the subfamily Triatominae, as well as the stridulatory sulcus and buccula. The buccula possess a thick edge, granular surface and “U” shape. The rostrum is similar in both sexes. The apical plate has a diamond shaped inferior lamella and the superior one has a digit form. In the apex of the rostrum two lateral rifts 1+1 are observed. The stridulatory sulcus of these specie is "V" shaped and is more larger in the females than in males. This is the first morphologic description of these structures in the adults of T. carcavalloi using the scanning electronic microscopy. The results related to the morphological studies carried out in T. carcavalloi, showed evidences that some structures are important for the specific characterization.
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Li, Yingping, and Ben Hewett. "Measurement of seawater average velocity using water bottom multiples from vertical seismic profile surveys." Interpretation 4, no. 4 (November 1, 2016): SQ13—SQ22. http://dx.doi.org/10.1190/int-2016-0022.1.
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Previous diagnoses of surface seismic velocity models with vertical seismic profile (VSP) data in the Gulf of Mexico have indicated that shallow velocities were poorly constrained by VSP due to ringing caused by multiple casing strings. This ringing also hampered direct measurement of the seawater average velocity (SWAV) at a rig site with direct arrivals of a zero-offset VSP (ZVSP). We have directly measured the SWAV at a rig site with a known water depth by using differential times between primary water bottom multiples (WBMs) and direct first arrivals acquired in a marine VSP survey. We developed a procedure to process ZVSP-WBM signals for SWAV measurement. This WBM method is successfully applied to VSP data recorded at 27 rig sites in the deep-water environments of North and South America. Our results suggest that VSP processors should implement this method and add the SWAV measurement in their future velocity survey reports. We have estimated water bottom depths using differential times. We found that the estimated water depths are comparable with those acquired from sonar measurements by autonomous underwater vehicles, but with large uncertainties. The WBM method is extended by using data from a vertical incidence VSP to measure a profile of the SWAV along the path of a deviated well and evaluate possible lateral variations of SWAV. This method can potentially be applied to a time-lapse VSP to monitor temporal variations of SWAV. We also evaluated the application scope and limitations of the WBM method.
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Novak, Ana, Andrej Šmuc, Sašo Poglajen, Bogomir Celarc, and Marko Vrabec. "Sound Velocity in a Thin Shallowly Submerged Terrestrial-Marine Quaternary Succession (Northern Adriatic Sea)." Water 12, no. 2 (February 18, 2020): 560. http://dx.doi.org/10.3390/w12020560.
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Estimating sound velocity in seabed sediment of shallow near-shore areas submerged after the Last Glacial Maximum is often difficult due to the heterogeneous sedimentary composition resulting from sea-level changes affecting the sedimentary environments. The complex sedimentary architecture and heterogeneity greatly impact lateral and horizontal velocity variations. Existing sound velocity studies are mainly focused on the surficial parts of the seabed sediments, whereas the deeper and often more heterogeneous sections are usually neglected. We present an example of a submerged alluvial plain in the northern Adriatic where we were able to investigate the entire Quaternary sedimentary succession from the seafloor down to the sediment base on the bedrock. We used an extensive dataset of vintage borehole litho-sedimentological descriptions covering the entire thickness of the Quaternary sedimentary succession. We correlated the dataset with sub-bottom sonar profiles in order to determine the average sound velocities through various sediment types. The sound velocities of clay-dominated successions average around 1530 m/s, while the values of silt-dominated successions extend between 1550 and 1590 m/s. The maximum sound velocity of approximately 1730 m/s was determined at a location containing sandy sediment, while the minimum sound velocity of approximately 1250 m/s was calculated for gas-charged sediments. We show that, in shallow areas with thin Quaternary successions, the main factor influencing average sound velocity is the predominant sediment type (i.e. grain size), whereas the overburden influence is negligible. Where present in the sedimentary column, gas substantially reduces sound velocity. Our work provides a reference for sound velocities in submerged, thin (less than 20 m thick), terrestrial-marine Quaternary successions located in shallow (a few tens of meters deep) near-shore settings, which represent a large part of the present-day coastal environments.
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Júnior, Paulo Veronez, Alex Cardoso Bastos, Bruno Furtado Pizzin, Reginaldo Dalmaschio Gava, Valéria da Silva Quaresma, and Cleverson Guizan Silva. "Sonar de varredura lateral e sísmica de alta resolução aplicados no estudo de ecofácies na baía de Vitória - ES." Revista Brasileira de Geofísica 27, no. 3 (September 2009). http://dx.doi.org/10.1590/s0102-261x2009000300009.
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Lessa, Guilherme, and Kalina Dias. "Distribuição espacial das litofácies de fundo da Baía de Todos os Santos." Quaternary and Environmental Geosciences 1, no. 2 (December 31, 2009). http://dx.doi.org/10.5380/abequa.v1i2.14376.
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Os estudos das fácies sedimentares superficiais da Baía de Todos os Santos (BTS) foram iniciados há mais de 30 anos, tendo sempre privilegiado as características texturais dos sedimentos. O mapeamento das fácies foi elaborado para diferentes setores, e as classificações texturais não são padronizadas. Este trabalho tem o objetivo de reavaliar a distribuição, padronizar a classificação e gerar um mapa único das fácies texturais na BTS. Além da digitalização e georreferenciamento dos mapas anteriores, o trabalho alia ainda registros de sonar de varredura lateral e amostras adicionais de sedimentos de fundo coletadas para a classificação de fácies sísmicas e melhor delineamento dos limites texturais. O mapeamento final indica a existência de onze fácies texturais, refina espacialmente o mapeamento em áreas com baixa densidade de amostras (resultando, por exemplo, na inclusão de uma fácies recifal) e indica a progradação, de aproximadamente 3 km, da fácies lamosa responsável pela colmatação atual da BTS.
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Quaresma, V. S., G. T. M. Dias, and J. A. Baptista Neto. "Caracterização da ocorrência de padrões de sonar de varredura lateral e sísmica de alta freqüência (3,5 e 7,0 kHz) na porção sul da Baía de Guanabara - RJ." Revista Brasileira de Geofísica 18, no. 2 (August 2000). http://dx.doi.org/10.1590/s0102-261x2000000200008.
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Finco, Jessica, and Jarbas Bonetti. "Caracterização da geodiversidade da plataforma continental interna a noroeste da Ilha do Arvoredo – SC através de dados geoacústicos e sedimentológicos." Brazilian Journal of Aquatic Science and Technology 24, no. 2 (September 24, 2020). http://dx.doi.org/10.14210/bjast.v24n1.14100.
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A caracterização da geodiversidade marinha consiste no mapeamento dos fatores abióticos que controlam, em ampla escala, a variabilidade dos fundos oceânicos. Neste contexto, o presente estudo tem como objetivo caracterizar a geodiversidade da plataforma continental interna a noroeste da Ilha do Arvoredo – SC. Para tal, foram utilizadas amostras sedimentares e dados geoacústicos adquiridos com um interferômetro EdgeTech 4600, o qual forneceu informações batimétricas, de retroespalhamento e de sonar de varredura lateral. Cada dado foi processado separadamente e a sua integração possibilitou a elaboração de um mapa síntese da geodiversidade local. Os resultados mostraram que a geomorfologia da área caracteriza-se pela presença de um canal em forma de “V”, sobre o qual ocorrem três depressões, além da existência de dois afloramentos rochosos, um emerso e outro não. Dentre as feições encontradas, destaca-se a ocorrência de um banco de rodolitos situado a partir dos 8m de profundidade e que recobre cerca de 825.000m². Também foram identificadas marcas onduladas na extremidade sul da área, sugerindo possível aumento da hidrodinâmica neste setor. Quanto à composição de fundo, observou-se a presença de altas concentrações de carbonato biodetrítico sobre o banco de rodolitos e concentrações consideravelmente mais baixas na plataforma arenosa adjacente ao costão NW (noroeste) da Ilha do Arvoredo (entre 0 e 8m de profundidade). Após a eliminação do carbonato biodetrítico das amostras, foi caracterizada a ocorrência de areia fina recobrindo a plataforma arenosa e areia média na área onde ocorrem rodolitos. A interferometria se mostrou uma técnica com boa aplicabilidade no levantamento de dados da plataforma continental interna visando a caracterização da geodiversidade local.
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"Nondestructive testing of submerged engineering structures by lateral sonar (In French)." International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts 23, no. 5 (October 1986): 188. http://dx.doi.org/10.1016/0148-9062(86)90153-1.
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LIBERTI, Edson Aparecido, Ii-Sei WATANABE, Rogério Albuquerque AZEREDO, Ana Maria MINARELLI, James Lindolph Roosevelt LEMOS, and Edmir MATSON. "Efeitos od laser CO2 na mandíbula de ratos: Estudo através da microscopia eletrônica de varredura." Revista de Odontologia da Universidade de São Paulo 11, suppl 1 (1997). http://dx.doi.org/10.1590/s0103-06631997000500011.
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A face lateral do corpo da mandíbula de ratos foi irradiada pelo laser CO2 com disparos contínuos de 10watts de potência. Após três meses, o sulco formado pela irradiação apresentou, em uma grande extensão, material fundido com diversas fraturas. Após sete meses, o periósteo neoformado recobriu amplas áreas da incisão, que apresentou ainda material carbonizado. Um ano após a incisão, o periósteo neoformado estava composto por fibras colágenas, que formaram feixes espessos, transversais à incisão, ou malhas regulares, que recobriram a incisão. Ainda nessa fase, resquícios de material carbonizado foram verificados, caracterizando um retardo na regeneração óssea
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Greenhall, J., V. K. Chillara, D. N. Sinha, and C. Pantea. "On the Bandwidth and Beam Profile Characteristics of a Simple Low-Frequency Collimated Ultrasound Beam Source." Journal of Vibration and Acoustics 143, no. 6 (May 4, 2021). http://dx.doi.org/10.1115/1.4050851.
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Abstract We numerically investigate the bandwidth and collimation characteristics of ultrasound beams generated by a simple collimated ultrasound beam source that consists of a piezoelectric disk operated near its radial mode resonances. We simulate the ultrasound beam generated in a fluid medium as a function of the excitation frequency for two cases: (1) free piezoelectric disk that corresponds to zero-traction along the lateral edge and (2) fixed piezoelectric disk that corresponds to zero-displacement along the lateral edge. We present and discuss the physical mechanism underpinning the frequency-dependent collimation and bandwidth properties of the ultrasound beams. We observe that the collimated beam generated by the free disk repeatedly lengthens/shortens and also extends/retracts sidelobes with increasing frequency. Alternatively, fixing the piezoelectric disk results in a consistent beam profile shape across a broad range of frequencies. This facilitates generating broadband signals such as a Gaussian pulse or chirp, which are common in ultrasound imaging. Thus, the fixed piezoelectric disk finds application as a collimated ultrasound beam source in a wide range of applications including medical ultrasound imaging, scanning acoustic microscopy, sonar detection, and other nondestructive ultrasound inspection techniques.
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Claudia Pirrotta, Maria Serafina Barbano, Daniela Pantosti, and Paolo Marco De Martini. "Evidence of active tectonics in the Augusta Basin (eastern Sicily, Italy) by Chirp sub-bottom sonar investigation." Annals of Geophysics 56, no. 5 (January 13, 2014). http://dx.doi.org/10.4401/ag-6371.
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<p>A Chirp sub-bottom sonar investigation was performed in the 150 km<sup>2</sup> wideAugustaBasin, located in the eastern Sicily Ionian coast, a region repeatedly hit by strong earthquakes in historical time, with the end of identifying possible evidence of active tectonics. Seismostratigraphy shows two main reflectors: R1, formed between 60 ka and 19 ka BP, and R2 that is the top of the Holocene deposits. Morphobathymetry reveals two marine abrasion surfaces, Ms1 and Ms2 that are related to the 35 ka and 25 ka BP marine high stills, respectively. This study highlights that R1 and the onlapping Holocene sediments are affected by normal and probably strike-slip faulting. A set of NE-SW striking normal faults represents the oldest system, because they dislocate R1 but not the Holocene deposit. NNW-SSE striking extensional faults show more recent activity since they displace Ms2, the Holocene sequence and cause seafloor up-warping. NE-SW normal faults produce asymmetric basins where the Holocene deposits form wedged bodies. ENE-WSW left-lateral faults dissect a paleo-island, Ms2 and the NNW-SSE fault system. Moreover, seismically induced slumps involving the Holocene sediments, are found at the foot of some fault scarps. The presence of slumped bodies and active faults indicates ongoing deformation in the basin. Identified active faults are consistent with the main regional Malta Escarpment fault system, of which they can be considered as the incipient westernmost extension. This study supports the hypothesis that the Malta Escarpment is active and can be responsible for the regional seismicity.</p>
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Pichone, Alinie, Gabriela Campos, Maurilo Leite Jr, and Carlos Perez Gomes. "High ankle-brachial index predicts cardiovascular events and mortality in hemodialysis patients with severe secondary hyperparathyroidism." Brazilian Journal of Nephrology, May 12, 2021. http://dx.doi.org/10.1590/2175-8239-jbn-2020-0218.
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Abstract Introduction: Vascular calcification related to severe secondary hyperparathyroidism (SHPT) is an important cause of cardiovascular and bone complications, leading to high morbidity and mortality in patients with chronic kidney disease (CKD) undergoing hemodialysis (HD). The present study aimed to analyze whether ankle-brachial index (ABI), a non-invasive diagnostic tool, is able to predict cardiovascular outcomes in this population. Methods: We selected 88 adult patients on HD for at least 6 months, with serum iPTH>1,000pg/mL. We collected clinical data, biochemical and hormonal parameters, and ABI (sonar-Doppler). Calcification was assessed by lateral radiography of the abdomen and by simple vascular calcification score (SVCS). This cohort was monitored prospectively between 2012 and 2019 for cardiovascular outcomes (death, myocardial infarction (MI), stroke, and calciphylaxis) to estimate the accuracy of ABI in this setting. Results: The baseline values were: iPTH: 1770±689pg/mL, P: 5.8±1.2 mg/dL, corrected Ca: 9.7±0.8mg/dL, 25(OH)vit D: 25.1±10.9ng/mL. Sixty-five percent of patients had ABI>1.3 (ranging from 0.6 to 3.2); 66% had SVCS≥3, and 45% aortic calcification (Kauppila≥8). The prospective evaluation (51.6±24.0 months), provided the following cardiovascular outcomes: 11% of deaths, 17% of nonfatal MI, one stroke, and 3% of calciphylaxis. After adjustments, patients with ABI≥1.6 had 8.9-fold higher risk of cardiovascular events (p=0.035), and ABI≥1.8 had 12.2-fold higher risk of cardiovascular mortality (p=0.019). Conclusion: The presence of vascular calcifications and arterial stiffness was highly prevalent in our population. We suggest that ABI, a simple and cost-effective diagnostic tool, could be used at an outpatient basis to predict cardiovascular events in patients with severe SHPT undergoing HD.