447 research outputs found

    On the Performance of LDPC-Coded MIMO Schemes for Underwater Communications Using 5G-like Processing

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    UIDB/EEA/50008/2020This article studies the underwater acoustic (UWA) communications associated with multiple input–multiple output (MIMO), single carrier with frequency-domain equalization (SC-FDE), and with low-density parity-check (LDPC) codes. Low-complexity receivers such as equal gain combining (EGC), maximum ratio combining (MRC), and iterative block—decision feedback equalization (IB-DFE) are studied in the above-described scenarios. Furthermore, due to the low carrier frequencies utilized in UWA communications, the performance of the proposed MIMO scenarios is studied at different levels of channel correlation between antennas. This article shows that the combined schemes tend to achieve good performances while presenting low complexity, even in scenarios with channel correlation between antennas.publishersversionpublishe

    Evaluation of zearalenone in vitro removal by Saccharomyces cerevisiae strains isolated from bovine forage

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    Zearalenone (ZEN) is a mycotoxin that has relatively low acute toxicity. However, it is a potent oestrogen, interfering with the reproductive tract of animals. Among other effects, ZEN decreases animals fertility, and induces fibrosis in the uterus, breast cancer and endometrial carcinoma (Zinedine et al., 2007). Anti-mycotoxin additives (AMA) are defined as a group of products that, when added to animal feed, are capable of adsorbing, inactivating, or neutralizing mycotoxins in the gastrointestinal tract of animals. One example of these products are adsorbents based on yeast cell walls, a safe and beneficial animal feed additive (Abreu et al., 2008). When based on active cells, yeast based products also act as a probiotic, contributing to improve the general animal health because it stimulates their immune system and promotes the integrity of intestinal mucosa (Albino et al., 2006). Strains of Saccharomyces cerevisiae isolated from silage were tested for their ZEN removal capability. Their effect on - and b-zearalenol (-ZOL and b-ZOL) was also tested. Strains were grown on YPD separately supplemented with ZEN, -ZOL and b-ZOL, and their elimination from culture media was quantified over time by HPLC-FL.This study was carried out with grants from CYTED (Acción 109ac0371), CNPq, CAPES-DS and FAPUR/UFRRJ (Brazil). Luís Abrunhosa was supported by grant SFRH/BPD/43922/2008 from Fundação para a Ciência e Tecnologia – FCT, Portugal.. Authors also acknowledge the support of the Society for Applied Microbiology – SfAM

    Extraction and characterization of extracellular polymeric substances from aerobic granular sludge from a full-scale sequencing batch reactor in Portugal

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    Microbiotec'17 - Congress of Microbiology and Biotechnology 2017Background: Aerobic granular sludge (AGS) is a recently developed technology for wastewater treatment. This system is able to manage higher amounts of wastewater and requires less surface area than conventional systems. The granules consist of microorganisms embedded in a self-produced extracellular polymeric substances (EPS) matrix. EPS are high molecular weight polymers, which can be metabolic products of microorganisms (e.g. proteins, polysaccharides, humic substances, nucleic acids) or be due to cell lyses. Accumulation on the cells surface of such EPS forms a protective barrier for the cells from the external environment. This work focus on the extraction and quantification of EPS from AGS from a large scale bioreactor in Portugal, during approximately 4 months. Given the environmental and chemical differences that these granules are subjected to one of the goals was to assess variability in the EPS production and characterize the granules morphology and composition in a large scale environment.The authors thank the company SIMTEJO for supplying the granules, and the financial support of European Social Fund, under Programa Operacional under the project NORTE-08-5369-FSE-000007 and BioTecNorte operation (NORTE-010145-FEDER-000004). This work was also supported by Portuguese Funds from FCT - Fundação para a Ciência e a Tecnologia through the strategic funding of UID/Multi/50016/2013 and UID/BIO/04469/2013 units and COMPETE 2020 (POCI-01-0145-FEDER-006684). C.L. Amorim wishes to acknowledge the research grant from FCT (SFRH/BPD/96481/2013).info:eu-repo/semantics/publishedVersio

    A digital-based integrated methodology for the preventive conservation of cultural heritage: the experience of HeritageCare project

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    A sustainable conservation strategy for cultural heritage protection is not feasible without a systematic documentation, registration and management of the information. The adoption of integrated inspection protocols and regular tracking processes, based on standardized procedures and uniform criteria, are the basis to successfully replace actual curative strategies with proactive conservation approaches. The opportunities brought by the digital tools can offer tremendous advantages in this regard. This paper explores the leading role that digitization is assuming in the context of heritage conservation through the experience of the HeritageCare project - Monitoring and preventive conservation of historic and cultural heritage" (SOE1/P5/P0258). The project has developed a digital-based integrated methodology aimed at providing enhanced tools and services to properly document cultural heritage buildings and engage directly owners in the conservation process of their legacy. The structured digital workflow on which the HeritageCare protocol relies is described in detail, encompassing different levels of information. Finally, the full application of the protocol is presented with reference to one of the most emblematic case studies of the project, the Ducal Palace of Guimaraes, Portugal.- This work was partly financed by FEDER funds through the Competitiveness Factors Operational Programme (COMPETE) and by national funds through the Foundation for Science and Technology (FCT) within the scope of project POCI-01-0145-FEDER-007633

    Efficiency improvement of vehicles using temperature controlled exhaust thermoelectric generators

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    One of the main obstacles for the use of thermoelectric generators (TEGs) in vehicles is the highly variable thermal loads typical of driving cycles. Under these conditions it will be virtually impossible for a conventional heat exchanger to avoid both thermal dilution under low thermal loads and TEG overheating under high thermal loads. The authors have been exploring an original heat exchanger concept able to address the aforementioned problems. It uses a variable conductance thermosiphon-based phase-change buffer between the heat source and the TEGs so that a nearly constant, optimized temperature is obtained regardless of operating conditions. To the best of the authors' knowledge, the thermal control feature of the system is unique among existing TEG concepts. The novelty of the present work is the actual computation of operating pressure and temperature and the corresponding vaporization and condensation rates inside the thermosiphon system during driving cycles along with the assessment of the influence of the volumes and pre-charge pressure on electrical output. The global energy and emission savings were also computed for a typical yearly driving profile. It was observed that indeed the concept has unparalleled potential for improving the efficiency of vehicles using TEGs, with around 6% fuel and CO2 emissions savings using the system. This seems a breakthrough for such light duty applications since the efficiency of conventional (passive) systems is strongly deprecated by thermal dilution under low thermal loads and the need to by-pass high thermal load events to avoid overheating. On the contrary, the present concept allows the control of the hot face temperature of the TEGs even under highly variable thermal load (i.e. driving cycle) environments.This work had the support of Fundacao para a Ciencia e Tecnologia, Project Exhaust2Energy (PTDC/EMS-ENE/3009/2014). MEtRICs - Mechanical Engineering and Resource Sustainability Centre (UID/EMS/04077/2019), sabbatical grant (J. Martins) SFRH/BSAB/142994/2018, Post-doctoral grant (F.P. Brito) SFRH/BPD/89553/2012 and M-ERA.NET Project THERMOSS, financed by FEDER funds through P.O. F.C. - COMPETE and National funds through PIDDAC

    A benchmark for validation of numerical results in sheet metal forming

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    Advances in FE codes for simulation of sheet metal forming processes have enabled its use during pre-production stage of a component. Some of recent developments include improvements and implementation of new material models of mechanical behaviour. However, these developments and corresponding results need to be validated, which means being compared with experimental results. On the other hand, in order that experimental results are a reference data, they need to be tested to repeatability and need to be obtained with such characteristic preferably by different institutions.http://www.sciencedirect.com/science/article/B6TGJ-4CS4NXC-M/1/11b425ff3006b6fcdad85f1f6b4fa57

    Freeform 3D printing using a continuous viscoelastic supporting matrix

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    Embedded bio-printing has fostered significant advances toward the fabrication of soft complex tissue-like constructs, by providing a physical support that allows the freeform shape maintenance within the prescribed spatial arrangement, even under gravity force. Current supporting materials still present major drawbacks for up-scaling embedded 3D bio-printing technology towards tissue-like constructs with clinically relevant dimensions. Herein, we report a a cost-effective and widely available supporting material for embedded bio-printing consisting on a continuous pseudo-plastic matrix of xanthan-gum (XG). This natural polisaccharide exhibits peculiar rheological properties that have enabled the rapid generation of complex volumetric 3D constructs with out of plane features. The freedom of design within the three orthogonal axes through the independent and controlled bio-printing process opens new opportunities to produce on demand large arbitrary shapes for personalized medicine. Additionally, we have demonstrated the versatile functionality of XG as a photocurable gel reservoir to engineer perfused cell-laden hydrogel constructs, addressing other practical biomedical applications such as in vitro models and organ-on-chip platforms.publishe

    Cannabidiol and cannabigerol exert antimicrobial activity without compromising skin microbiota

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    Cannabidiol (CBD) and cannabigerol (CBG) are two pharmacologically active phytocannabinoids of Cannabis sativa L. Their antimicrobial activity needs further elucidation, particularly for CBG, as reports on this cannabinoid are scarce. We investigated CBD and CBG’s antimicrobial potential, including their ability to inhibit the formation and cause the removal of biofilms. Our results demonstrate that both molecules present activity against planktonic bacteria and biofilms, with both cannabinoids removing mature biofilms at concentrations below the determined minimum inhibitory concentrations. We report for the first time minimum inhibitory and lethal concentrations for Pseudomonas aeruginosa and Escherichia coli (ranging from 400 to 3180 µM), as well as the ability of cannabinoids to inhibit Staphylococci adhesion to keratinocytes, with CBG demonstrating higher activity than CBD. The value of these molecules as preservative ingredients for cosmetics was also assayed, with CBG meeting the USP 51 challenge test criteria for antimicrobial effectiveness. Further, the exact formulation showed no negative impact on skin microbiota. Our results suggest that phytocannabinoids can be promising topical antimicrobial agents when searching for novel therapeutic candidates for different skin conditions. Additional research is needed to clarify phytocannabinoids’ mechanisms of action, aiming to develop practical applications in dermatological use.info:eu-repo/semantics/publishedVersio

    mHealth in urology

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    Introduction: Smartphones are increasingly playing a role in healthcare and previous studies assessing medical applications (apps) have raised concerns about lack of expert involvement and low content accuracy. However, there are no such studies in Urology. We reviewed Urology apps with the aim of assessing the level of participation of healthcare professionals (HCP) and scientific Urology associations in their development. Material and Methods: A systematic search was performed on PubMed, Apple's App Store and Google's Play Store, for Urology apps, available in English. Apps were reviewed by three graders to determine the app's platform, target customer, developer, app type, app category, price and the participation of a HCP or a scientific Urology association in the development. Results: The search yielded 372 apps, of which 150 were specific for Urology. A fifth of all apps had no HCP involvement (20.7%) and only a third had been developed with a scientific Urology association (34.7%). The lowest percentage of HCP (13.4%) and urological association (1.9%) involvement was in apps designed for the general population. Furthermore, there was no contribution from an Urology society in "Electronic Medical Record" nor in "Patient Information" apps. A limitation of the study is that only Android and iOS apps were reviewed. Conclusions: Despite the increasing Mobile Health (mHealth) market, this is the first study that demonstrates the lack of expert participation in the design of Urology apps, particularly in apps designed for the general public. Until clear regulation is enforced, the urological community should help regulate app development. Maintaining a register of certified apps or issuing an official scientific seal of approval could improve overall app quality. We propose that urologists become stakeholders in mHealth, shaping future app design and promoting peer-review app validation

    A atitude do educador de infância e a participação da criança como referenciais de qualidade em educação

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    Neste artigo, fundamentado em dois estudos de caso em jardim de infância, refletiu- -se sobre como e com quais ferramentas de apoio se pode avaliar e promover qualidade e intervenção educativa adequada nos contextos. Selecionou-se um grupo de crianças (entre 3 e 6 anos) e desenvolveram-se estratégias com a finalidade de escutar e compreender o modo como elas participam. Ainda, em diversos tempos da rotina de cada contexto, identificaram-se interações e atitudes do educador, analisando-se o respetivo impacto no nível da participação das crianças. Os resultados revelaram que, quando as crianças desenvolvem um sentimento de pertença ao contexto e lhes são oferecidas oportunidades de participação, mais facilmente se envolvem, revelam bem-estar emocional e motivação para aprender, explorar e participar nos processos de tomada de decisão. A escuta ativa, o questionamento e o encorajamento do diálogo assumem-se, por parte do adulto, competências essenciais para a qualidade da intervenção educativa.This paper, based on two case studies in a kindergarten context, describes a reflection on the most appropriate method and tools for the assessment and promotion of quality and context intervention. A group of children (between 3 and 6 years old) was selected and strategies were developed in order to listen to the children’s voices and understand how they were participating. Moreover, in different routine times within each context, interactions and attitudes of educators were identified, with the corresponding analysis of the impact on children’s participation. The results revealed that when children develop a sense of belonging in the context and they are offered opportunities to participate, they more easily get engaged, reveal emotional wellbeing and motivation to learn, explore and participate in decision-making processes. For the adult, active listening, questioning and encouragement of dialogue appear as essential skills to promote quality in educational intervention.En el presente artículo, basado en dos estudios de caso en un jardín de infancia, se reflexionó sobre cómo y con qué herramientas de apoyo se puede evaluar y promover calidad e intervención educativa apropiada en los contextos. Se seleccionó un grupo de niños (entre los 3 y 6 años de edad) y se desarrollaron estrategias con la finalidad de escuchary comprender el modo como dichos niños participan. Además, en diversos momentos de la rutina de cada contexto, se identificaron interacciones y actitudes del educador, analizando el respectivo impacto en la participación de los infantes. Los resultados revelaron que, cuando los niños desarrollan un sentido de pertenencia al contexto y se les ofrece la oportunidad de participar, más fácilmente se envuelven, revelan bienestar emocional y motivación para aprender, explorar y participar en la toma de decisiones. La escucha activa, el cuestionar y fomentar el diálogo constituyen, para el adulto, competencias esenciales para la calidad de la intervención educativa
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