Browsing by Author "Martins, C."
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- Acoustic maritime rapid environmental assessment 2004 during the MREA'04 sea trialPublication . Jesus, S. M.; Soares, C.; Felisberto, P.; Silva, A.; Farinha, L.; Martins, C.Environmental inversion of acoustic signals for bottom and water column properties is being proposed in the literature as an interesting concept for complementing direct hydrographic and oceanographic measurements for Rapid Environmental Assessment (REA). The acoustic contribution to REA can be cast as the result of the inversion of ocean acoustic properties to be assimilated into ocean circulation models specifically tailored and calibrated to the scale of the area under observation. Traditional ocean tomography systems and methods for their requirements of long and well populated receiving arrays and precise knowledge of the source/receiver geometries are not well adapted to operational Acoustic REA (AREA). The Acoustic Oceanographic Buoy (AOB) was proposed as an innovative concept that responds to the operational requirements of AREA. That concept includes the development of water column and geo-acoustic inversion methods being able to retrieve environmental true properties from signals received on a drifting network of acoustic-oceanographic sensors - the AOBs. An AOB prototype and a preliminary version of the inversion code, was tested at sea during the Maritime Rapid Environmental Assessment 2003 (MREA’03) sea trial and was reported in [1]. On a separate register it should be noted that the characterization of the environment between the source and the receiver also contributes to the identification of the acoustic channel response and therefore provides a basis for fulfilling the objectives of project NUACE1. The present report describes the data sets and results gathered during the MREA’04 sea trial that took place from 29 March to 19 April 2004 off the west coast of Portugal, south of Lisboa (Portugal), with the objectives of testing an improved version of the individual AOB and its functionality in a simple network. The acoustic part of the experiment lasted for four days between April 7 and April 10, 2004 and involved the transmission and reception of pre-coded signals along range-dependent and range-independent acoustic tracks.
- Acoustic monitoring of the oxygen production of a seagrass meadowPublication . Felisberto, P.; Zabel, F.; Martins, C.; Jesus, S. M.This paper discusses the data acquired in the Bay of la Revellata, Calvi, Corsica during October 2011 for the purpose of developing an acoustic system for monitoring the oxygen production of a seagrass meadow. In a range dependent very shallow water area, densely covered by Posidonia Oceanica seagrass , a sound source transmitted chirp signals in 3 different bands (400-800Hz, 1.5-3.5kHz and 6.5-8.5kHz) to 100m distant 3 self-recording hydrophones during a period of one week. Preliminary data analysis shown a possible correlation between the oxygen production and the instantaneous impulse responses observed. Using a simple procedure to estimate the received power allows to obtain figures of variability along time that seem to be highly correlated with oxygen production and show similar trend with oxygen measurements by optodes conducted in the same area. Those preliminary results show that a light acoustic system can potentially be used in a monitoring system to quantify the oxygen production of a seagrass meadow. The calibration of the acoustic method with other oxygen measurements is an ongoing work.
- Acoustic oceanographic buoy (version 1)Publication . Silva, A.; Martins, C.; Jesus, S. M.One of the known impairements in the application of ocean acoustic tomography in operational scenarios has been the size, weight and difficulty of operation of actual ocean going equipment, such as hydrophone arrays and acoustic sources. The Acoustic Oceanographic Buoy - AOB is meant to be, at its final stage, an easy to deploy and easy to maintain autonomous vertical array that puts together in a single system acoustic and non-acoustic sensors, self-storing of geotime and GPS referred data, on the buoy preprocessing capabilities and network seamless integrability and data online transfer via a wireless lan high speed link. These capabilities make the AOB a versatile system for a variety of applications such as ocean tomography, underwater communications, rapid environmental assessment (REA), passive and multistatic sonar and underwater target tracking. The AOB version 1 described in this report was developed between 2003 and 2004 and tested at sea during the MREA’03 and MREA’04 sea trials.
- Acoustic oceanographic buoy (version 2)Publication . Zabel, F.; Martins, C.This report describes an underwater acoustic data acquisition system, which uses a surface buoy and an underwater array of acoustic and non-acoustic sensors. The surface buoy includes a digital storage unit for the acquired data, a communications system for remote monitoring and data transmission, a digital processing unit for pre-processing of acquired data and a battery power supply. A user manual is included as an installation, setup and maintenance guide for the system and its practical applications. The developed hardware and software is described in detail. Detailed schematics and designs can be found in the final section of this document, these can be used to develop the system, perform maintenance, purchase spare parts or perform any type of modifications.
- Acoustic oceanographic buoy telemetry system: an ‘advanced’ sonobuoy that meets acoustic rapid environmental assessment requirementsPublication . Silva, A.; Zabel, F.; Martins, C.The Acoustic Oceanographic Buoy (AOB) Telemetry System has been designed to meet acoustic rapid environmental assessment requirements. It uses a standard institute of Electrical and Electronics Engineers 802.11 wireless local area network (WLAN) to integrate the air radio network (RaN) and a hydrophone array and acoustic source to integrate the underwater acoustic network (AcN). It offers advantages including local data storage, dedicated signal processing, and global positioning system (GPS) timing and localization. The AOB can also be integrated with other similar systems, due to its WLAN transceivers, to form a flexible network and perform on-line high speed data transmissions. The AOB is a reusable system that requires less maintenance and can also work as a salt-water plug-and-play system at sea as it is designed to operate in free drifting mode. The AOB is also suitable for performing distributed digital signal processing tasks due to its digital signal processor facility.
- Analog 16-hydrophone vertical line array for the acoustic - oceanographic buoy - AOBPublication . Zabel, F.; Martins, C.; Silva, A.This report contains the user guide and the system reference for the analog 16-hydrophone AOB vertical line array. The array is a 67.5m long cable with 16 4m-spaced hydrophones and 17 digital thermistor sensors, distributed along its length. Each module has a dedicated preamplifier to increase signal strength at the hydrophone output and drive a balanced line to transmit the signal to the surface buoy's electronics. The thermistor sensors are digital devices that transmit the temperatures values through a 1-wire digital serial bus. This report presents the system user guide and the system reference guide. The user guide has instructions for system deployment, everyday usage and maintenance. The system reference guide is intended for specialized technicians for system repairing and/or upgrade.
- Design of a UAN node capable of high-data rate transmission dual-link multinode underwater commuinication access point allows transmission of large amounts of data to shorePublication . Zabel, F.; Martins, C.; Silva, A.In recent years, underwater acoustic networks have become one of the most challenging topics in ocean acoustics.
- Dietary nitrogen and fish welfarePublication . Conceição, L. E. C.; Aragão, C.; Dias, J.; Costas, B.; Terova, G.; Martins, C.; Tort, L.Little research has been done in optimizing the nitrogenous fraction of the fish diets in order to minimize welfare problems. The purpose of this review is to give an overview on how amino acid (AA) metabolism may be affected when fish are under stress and the possible effects on fish welfare when sub-optimal dietary nitrogen formulations are used to feed fish. In addition, it intends to evaluate the current possibilities, and future prospects, of using improved dietary nitrogen formulations to help fish coping with predictable stressful periods. Both metabolomic and genomic evidence show that stressful husbandry conditions affect AA metabolism in fish and may bring an increase in the requirement of indispensable AA. Supplementation in arginine and leucine, but also eventually in lysine, methionine, threonine and glutamine, may have an important role in enhancing the innate immune system. Tryptophan, as precursor for serotonin, modulates aggressive behaviour and feed intake in fish. Bioactive peptides may bring important advances in immunocompetence, disease control and other aspects of welfare of cultured fish. Fishmeal replacement may reduce immune competence, and the full nutritional potential of plant-protein ingredients is attained only after the removal or inactivation of some antinutritional factors. This review shows that AA metabolism is affected when fish are under stress, and this together with sub-optimal dietary nitrogen formulations may affect fish welfare. Furthermore, improved dietary nitrogen formulations may help fish coping with predictable stressful events.
- O impacto da formação comunitária em SBV-DAE na sobrevivência à PCR. O que sabemos do mundo e de Portugal?Publication . Mourão, C.; Martins, C.; Vicente, L.; Cartaxo, V.Paragem cardiorrespiratória (PCR) extra-hospitalar representa um problema de saúde pública em todo o mundo, pela elevada incidência, baixa sobrevida e imprevisibilidade. O cidadão comum é crucial na possibilidade de iniciar a reanimação cardiopulmonar (RCP). O seu sucesso depende do reconhecimento precoce de PCR, rápido reporte à emergência pré-hospitalar, início atempado da RCP, com compressões e ventilações de elevada qualidade; desfibrilhação precoce com recurso ao Desfibrilhador Automático Externo (DAE) e transporte célere para o hospital de referência. A American Heart Association (AHA) recomendou a necessidade de reporte dos outcomes da PCR. A formação na comunidade para os cidadãos revela-se o pilar de uma efetiva RCP e do aumento da taxa de sobrevida da vítima de PCR.Assim, torna-se lícito colocar as seguintes questões: O que se sabe de PCR e RCP no mundo? E em Portugal? Haverá impacto da formação em Suporte Básico de Vida (SBV-DAE) na população em geral?
- Maritime rapid environmental assessment - Blue Planet'2007. Acoustic oceanographic buoys data reportPublication . Jesus, S. M.; Zabel, F.; Martins, C.Among the existing panoply of instrumentation for Rapid Environmental Assessment (REA), underwater unmanned vehicles, satellite remote sensing and oceanographic drifters attract particular attention. In the last years, there has been a growing interest in coupling purely oceanographic surveys and acoustic measurements, in order to provide a final environmental image that is not only oceanographically consistent but also acoustically coherent for the area and period of interest. Thus, the usage of remote acoustic equipment is becoming an integrand part of the REA equipment list. One of the major characteristics of REA equipment is its unique capability for remote, often unsupervised, operation and compactness.
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