1,319 research outputs found

    The automatic detection subsystem

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    Marques, M. M., Lobo, V., Aguiar, A. P., Silva, J. E., de Sousa, J. B., Nunes, M. D. F., Ribeiro, R. A., Bernardino, A., Cruz, G., & Marques, J. S. (2021). An unmanned aircraft system for maritime operations: The automatic detection subsystem. Marine Technology Society Journal, 55(1), 38-49. https://doi.org/10.4031/MTSJ.55.1.4 --- This work was funded by POFC (Programa Operacional Factores de Competitividade) within the National Strategic Reference Framework (QREN) under grant agreement 2013/034063 (SEAGULL, Project Number 34063).This paper addresses the development of an integrated system to support maritime situation awareness based on unmanned aerial vehicles (UAVs), empha-sizing the role of the automatic detection subsystem. One of the main topics of research in the SEAGULL project was the automatic detection of sea vessels from sensors onboard the UAV, to help human operators in the generation of situational awareness of maritime events such as (a) detection and geo-referencing of oil spills or hazardous and noxious substances, (b) tracking systems (e.g., vessels, ship-wrecks, lifeboats, debris), (c) recognizing behavioral patterns (e.g., vessels rendez-vous, high-speed vessels, atypical patterns of navigation), and (d) monitoring environmental parameters and indicators. We describe a system composed of optical sensors, an embedded computer, communication systems, and a vessel detection algorithm that can run in real time in the embedded UAV hardware and provide to human operators vessel detections with low latency, high precision rates (about 99%), and suitable recalls (>50%), which is comparable to other more computationally intensive state-of-the-art approaches. Field test results, including the detection of lifesavers and multiple vessels in red-green-and-blue (RGB) and thermal images, are presented and discussed.publishersversionpublishe

    De novo human angiotensin-converting enzyme 2 decoy NL-CVX1 protects mice from severe disease after severe acute respiratory syndrome Coronavirus 2 infection

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    © The Author(s) 2023. Published by Oxford University Press on behalf of Infectious Diseases Society of America. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited.The emergence of novel variants of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) underscores the need to investigate alternative approaches to prevent infection and treat patients with coronavirus disease 2019. Here, we report the preclinical efficacy of NL-CVX1, a de novo decoy that blocks virus entry into cells by binding with nanomolar affinity and high specificity to the receptor-binding domain of the SARS-CoV-2 spike protein. Using a transgenic mouse model of SARS-CoV-2 infection, we showed that a single prophylactic intranasal dose of NL-CVX1 conferred complete protection from severe disease following SARS-CoV-2 infection. Multiple therapeutic administrations of NL-CVX1 also protected mice from succumbing to infection. Finally, we showed that infected mice treated with NL-CVX1 developed both anti-SARS-CoV-2 antibodies and memory T cells and were protected against reinfection a month after treatment. Overall, these observations suggest NL-CVX1 is a promising therapeutic candidate for preventing and treating severe SARS-CoV-2 infections.This project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreements number 852985.info:eu-repo/semantics/publishedVersio

    De novo human angiotensin - converting enzyme 2 Decoy NL-CVX1 protects mice from severe disease after severe acute respiratory syndrome coronavirus 2 infection

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    The emergence of novel variants of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) underscores the need to investigate alternative approaches to prevent infection and treat patients with coronavirus disease 2019. Here, we report the preclinical efficacy of NL-CVX1, a de novo decoy that blocks virus entry into cells by binding with nanomolar affinity and high specificity to the receptor-binding domain of the SARS-CoV-2 spike protein. Using a transgenic mouse model of SARS-CoV-2 infection, we showed that a single prophylactic intranasal dose of NL-CVX1 conferred complete protection from severe disease following SARS-CoV-2 infection. Multiple therapeutic administrations of NL-CVX1 also protected mice from succumbing to infection. Finally, we showed that infected mice treated with NL-CVX1 developed both anti-SARS-CoV-2 antibodies and memory T cells and were protected against reinfection a month after treatment. Overall, these observations suggest NL-CVX1 is a promising therapeutic candidate for preventing and treating severe SARS-CoV-2 infections.info:eu-repo/semantics/publishedVersio

    Structural monitoring and modeling of the mechanical deformation of three-dimensional printed poly(ε-caprolactone) scaffolds

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    Three-dimensional (3D) printed poly(ε-caprolactone) (PCL) based scaffolds have being proposed for different tissue engineering applications. This study addresses the design and fabrication of 3D PCL constructs with different struts alignments at 90°, 45° and 90° with offset. The morphology and the mechanical behavior under uniaxial compressive load were assessed at different strain percentages. The combination of a new compressionCT device and micro computed tomography (micro-CT) allowed understanding the influence of pore geometry under controlled compressive strain in the mechanical and structural behavior of PCL constructs. Finite element analysis (FEA) was applied using the micro-CT data to modulate the mechanical response and compare with the conventional uniaxial compression tests. Scanning electron microscopic analysis showed a very high level of reproducibility and a low error comparing with the theoretical values, confirming that the alignment and the dimensional features of the printed struts are reliable. The mechanical tests showed that the 90° architecture presented the highest stiffness. With the compressionCT device was observed that the 90° and 90° with offset architectures presented similar values of porosity at same strain and similar pore size, contrary to the 45° architecture. Thus, pore geometric configurations affected significantly the deformability of the all PCL scaffolds under compression. The prediction of the FEA showed a good agreement to the conventional mechanical tests revealing the areas more affected under compression load. The methodology proposed in this study using 3D printed scaffolds with compressionCT device and FEA is a framework that offers great potential in understanding the mechanical and structural behavior of soft systems for different applications, including for the biomedical engineering field.The author Fernandes E M acknowledges the financial support from the Portuguese Foundation for Science and Technology (FCT) and 'Programa Operacional Potencial Humano-POPH' and 'Fundo Social Europeu-FSE' for the post-doctoral grant (SFRH/BPD/96197/2013).info:eu-repo/semantics/publishedVersio

    Mission and system architecture for an operational network of earth observation satellite nodes

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    Nowadays, constellations and distributed networks of satellites are emerging as clear development trends in the space system market to enable augmentation, enhancement, and possibilities of new applications for future Earth Observation (EO) missions. While the adoption of these satellite architectures is gaining momentum for the attaining of ever more stringent application requirements and stakeholder needs, the efforts to analyze their benefits and suitability, and to assess their impact for future programmes remains as an open challenge to the EO community. In this context, this paper presents the mission and system architecture conceived during the Horizon 2020 ONION project, a European Union research activity that proposes a systematic approach to the optimization of EO space infrastructures. In particular, ONION addressed the design of complementary assets that progressively supplement current programs and took part in the exploration of needs and implementation of architectures for the Copernicus Space Component for EO. Among several use cases considered, the ONION project focused on proposing system architectures to provide improved revisit time, data latency and image resolution for a demanding application scenario of interest: Marine Weather Forecast (MWF). A set of promising system architectures has been subject of a comprehensive assessment, based on mission analysis expertise and detailed simulation for evaluating several key parameters such as revisit time and data latency of each measurement of interest, on-board memory evolution and power budget of each satellite of the constellation, ground station contacts and inter-satellite links. The architectures are built with several heterogeneous satellite nodes distributed in different orbital planes. Each platform can embark different instrument sets, which provide the required measurements for each use case. A detailed mission analysis has then been performed to the selected architecture for the MWF use case, including a refined data flow analysis to optimize system resources; a refined power budget analysis; a delta-V and a fuel budget analysis considering all the possible phases of the mission. This includes from the correction of launcher injection errors and acquisition of nominal satellite position inside the constellation, orbit maintenance to control altitude, collision avoidance to avoid collision with space debris objects and end-of-life (EOL) disposal to comply with EOL guidelines. The relevance of the system architecture selected for the MWF has been evaluated for three use cases of interest (Arctic sea-ice monitoring, maritime fishery pressure and aquaculture, agricultural hydric stress) to show the versatility and the feasibility of the chosen architecture to be adapted for other EO applications.This project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 687490

    Dynamic culturing of cartilage tissue: the significance of hydrostatic pressure

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    Human articular cartilage functions under a wide range of mechanical loads in synovial joints, where hydrostatic pressure (HP) is the prevalent actuating force. We hypothesized that the formation of engineered cartilage can be augmented by applying such physiologic stimuli to chondrogenic cells or stem cells, cultured in hydrogels, using custom-designed HP bioreactors. To test this hypothesis, we investigated the effects of distinct HP regimens on cartilage formation in vitro by either human nasal chondrocytes (HNCs) or human adipose stem cells (hASCs) encapsulated in gellan gum (GG) hydrogels. To this end, we varied the frequency of low HP, by applying pulsatile hydrostatic pressure or a steady hydrostatic pressure load to HNC-GG constructs over a period of 3 weeks, and evaluated their effects on cartilage tissue-engineering outcomes. HNCs (10 · 106 cells/ mL) were encapsulated in GG hydrogels (1.5%) and cultured in a chondrogenic medium under three regimens for 3 weeks: (1) 0.4MPa Pulsatile HP; (2) 0.4MPa Steady HP; and (3) Static. Subsequently, we applied the pulsatile regimen to hASC-GG constructs and varied the amplitude of loading, by generating both low (0.4 MPa) and physiologic (5 MPa) HP levels. hASCs (10x106 cells/mL) were encapsulated in GG hydrogels (1.5%) and cultured in a chondrogenic medium under three regimens for 4 weeks: (1) 0.4MPa Pulsatile HP; (2) 5MPa Pulsatile HP; and (3) Static. In the HNC study, the best tissue development was achieved by the pulsatile HP regimen, whereas in the hASC study, greater chondrogenic differentiation and matrix deposition were obtained for physiologic loading, as evidenced by gene expression of aggrecan, collagen type II, and sox-9; metachromatic staining of cartilage extracellular matrix; and immunolocalization of collagens. We thus propose that both HNCs and hASCs detect and respond to physical forces, thus resembling joint loading, by enhancing cartilage tissue development in a frequency- and amplitude-dependant manner.Fundação para a Ciência e a Tecnologia (FCT) - SFRH/BD/42316/200

    Priority questions for biodiversity conservation in the Mediterranean biome: Heterogeneous perspectives across continents and stakeholders

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    International audienceThe identification of research questions with high relevance for biodiversity conservation is an important step towards designing more effective policies and management actions, and to better allocate funding among alternative conservation options. However, the identification of priority questions may be influenced by regional differences in biodiversity threats and social contexts, and to variations in the perceptions and interests of different stakeholders. Here we describe the results of a prioritization exercise involving six types of stakeholders from the Mediterranean biome, which includes several biodiversity hotspots spread across five regions of the planet (Europe, Africa, North and South America, and Australia). We found great heterogeneity across regions and stakeholder types in the priority topics identified and disagreement among the priorities of research scientists and other stakeholders. However, governance, climate change, and public participation issues were key topics in most regions. We conclude that the identification of research priorities should be targeted in a way that integrates the spectrum of stakeholder interests, potential funding sources and regional needs, and that further development of interdisciplinary studies is required. The key questions identified here provide a basis to identify priorities for research funding aligned with biodiversity conservation needs in this biome

    The Dimorphos ejecta plume properties revealed by LICIACube

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    The Double Asteroid Redirection Test (DART) had an impact with Dimorphos (a satellite of the asteroid Didymos) on 26 September 20221. Ground-based observations showed that the Didymos system brightened by a factor of 8.3 after the impact because of ejecta, returning to the pre-impact brightness 23.7 days afterwards2. Hubble Space Telescope observations made from 15 minutes after impact to 18.5 days after, with a spatial resolution of 2.1 kilometres per pixel, showed a complex evolution of the ejecta3, consistent with other asteroid impact events. The momentum enhancement factor, determined using the measured binary period change4, ranges between 2.2 and 4.9, depending on the assumptions about the mass and density of Dimorphos5. Here we report observations from the LUKE and LEIA instruments on the LICIACube cube satellite, which was deployed 15 days in advance of the impact of DART. Data were taken from 71 seconds before the impact until 320 seconds afterwards. The ejecta plume was a cone with an aperture angle of 140 ± 4 degrees. The inner region of the plume was blue, becoming redder with increasing distance from Dimorphos. The ejecta plume exhibited a complex and inhomogeneous structure, characterized by filaments, dust grains and single or clustered boulders. The ejecta velocities ranged from a few tens of metres per second to about 500 metres per second.This work was supported by the Italian Space Agency (ASI) in the LICIACube project (ASI-INAF agreement AC no. 2019-31-HH.0) and by the DART mission, NASA contract 80MSFC20D0004. M.Z. acknowledges Caltech and the Jet Propulsion Laboratory for granting the University of Bologna a licence to an executable version of MONTE Project Edition software. M.Z. is grateful to D. Lubey, M. Smith, D. Mages, C. Hollenberg and S. Bhaskaran of NASA/JPL for the discussions and suggestions regarding the operational navigation of LICIACube. G.P. acknowledges financial support from the Centre national d’études spatiales (CNES, France). A.C.B. acknowledges funding by the NEO-MAPP project (grant agreement 870377, EC H2020-SPACE-2019) and by the Ministerio de Ciencia Innovación (PGC 2018) RTI2018-099464-B-I00. F.F. acknowledges funding from the Swiss National Science Foundation (SNSF) Ambizione (grant no. 193346). J.-Y.L. acknowledges the support from the NASA DART Participating Scientist Program (grant no. 80NSSC21K1131). S.D.R. and M.J. acknowledge support from the Swiss National Science Foundation (project no. 200021_207359)
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