329 research outputs found

    State of the art nano materials

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    ABSTRACT: The special issue of ANM2017 is a collection of papers from the 9th series ANM (Advanced Nano Materials) conference, which was held at the University of Aveiro, Portugal, from 19-21 July 2017. State of the art results were discussed by eminent researchers on a wide range of subjects including nanomaterials, graphene materials, polymer nanocomposites, magnetic materials, spintronics materials, hydrogen energy, nanoelectronics and solar energy materials. We thank all the reviewers for their detailed reviews which immensely helped the authors to improve the quality of their papers. Advanced Nano Materials, ANM (https://www.advancednanomaterials-conference.com/) is an annual conference at the University of Aveiro, Portugal and we invite all our colleagues working in the field of energy materials to attend the next ANM.info:eu-repo/semantics/publishedVersio

    State of the art energy materials

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    ABSTRACT: The special issue of AEM2017 is a collection of papers from the second series of AEM (Advanced Energy Materials) conference, which was held at the University of Surrey, England, from 11-13 September 2017. State of the art results were discussed by eminent researchers on a wide range of subjects including battery, fuel cells, catalysis, carbon materials, photovoltaics, biofuels, polymer-based hydrogen storage, hydrogen production by various methods, crystalline porous materials for hydrogen storage. We thank all the reviewers for their detailed reviews which immensely helped the authors to improve the quality of their papers. Advanced Energy Materials, AEM (www.advanced-energymaterialsconference.com) is an annual conference and we invite all our colleagues working in the field of energy materials to attend the next AEM.info:eu-repo/semantics/publishedVersio

    Novel precoded relay-assisted algorithm for cellular systems

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    Cooperative schemes are promising solutions for cellular wireless systems to improve system fairness, extend coverage and increase capacity. The use of relays is of significant interest to allow radio access in situations where a direct path is not available or has poor quality. A data precoded relay-assisted scheme is proposed for a system cooperating with 2 relays, each equipped with either a single antenna or 2-antenna array. However, because of the half-duplex constraint at the relays, relaying-assisted transmission would require the use of a higher order constellation than in the case when a continuous link is available from the BS to the UT. This would imply a penalty in the power efficiency. The simple precoding scheme proposed exploits the relation between QPSK and 16-QAM, by alternately transmitting through the 2 relays, achieving full diversity, while significantly reducing power penalty. Analysis of the pairwise error probability of the proposed algorithm with a single antenna in each relay is derived and confirmed with numerical results. We show the performance improvements of the precoded scheme, relatively to equivalent distributed SFBC scheme employing 16-QAM, for several channel quality scenarios. Copyright © 2010 Sara Teodoro, et al.European project CODIVPortuguese project CADWINPortuguese project AGILEFC

    General dissipation coefficient in low-temperature warm inflation

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    In generic particle physics models, the inflaton field is coupled to other bosonic and fermionic fields that acquire large masses during inflation and may decay into light degrees of freedom. This leads to dissipative effects that modify the inflationary dynamics and may generate a nearly-thermal radiation bath, such that inflation occurs in a warm rather than supercooled environment. In this work, we perform a numerical computation and obtain expressions for the associated dissipation coefficient in supersymmetric models, focusing on the regime where the radiation temperature is below the heavy mass threshold. The dissipation coefficient receives contributions from the decay of both on-shell and off-shell degrees of freedom, which are dominant for small and large couplings, respectively, taking into account the light field multiplicities. In particular, we find that the contribution from on-shell decays, although Boltzmann-suppressed, can be much larger than that of virtual modes, which is bounded by the validity of a perturbative analysis. This result opens up new possibilities for realizations of warm inflation in supersymmetric field theories.Comment: 25 pages, 13 figures; revised version with new results added; published in JCA

    Structure and diversity of shallow soft-bottom benthic macrofauna in the Gulf of Lions (NW Mediterranean).

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    14 páginas, 10 figuras, 4 tablas.Samples of soft-sediment macrobenthos from 92 sites between 10 and 50 m depth were used to assess (1) the main soft-bottom macrofauna communities in the Gulf of Lions, (2) the different components of the diversity of benthic macrofauna in this area, and (3) the relevance of the use of major taxonomic groups as surrogates for the analysis of the structure and diversity of total macrofauna. Three main communities were identified by cluster analysis and associated procedures. These communities corresponded well to the assemblages recently identified on the basis of polychaete composition. The a-diversity indices were in accordance with those reported for similar communities in the Mediterranean. Conversely, the b-diversity value was higher than the few other data available in the literature for marine soft-bottom macrofauna. The total number of species in the studied area estimated by the ‘‘total species accumulation curve’’ (TS) method was 2,319, which was only 10% higher than the number obtained by extrapolation of the species–area curve. The similarity matrix based on polychaetes correlated best with the one based on total macrofauna. Polychaetes and crustaceans were also the best surrogates of total macrofauna when assessing a-diversity (except in the case of D*). Conversely, molluscs were the best surrogates of total macrofauna b-diversity. Our results show that the choice of an optimal surrogate for total benthic macrofauna depends on the characteristic of the benthic macrofauna to be studied. Moreover, this choice is also dependent on the environment to be studiedThis work is part of the PhD thesis of Ce´line Labrune. It was carried out within the EC Network of Excellence MARBEF. Ce´line Labrune was supported by the SYSCOLAG project run by the Re´gion Languedoc-Roussillon.Peer reviewe

    Warming up for Planck

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    The recent Planck results and future releases on the horizon present a key opportunity to address a fundamental question in inflationary cosmology of whether primordial density perturbations have a quantum or thermal origin, i.e. whether particle production may have significant effects during inflation. Warm inflation provides a natural arena to address this issue, with interactions between the scalar inflaton and other degrees of freedom leading to dissipative entropy production and associated thermal fluctuations. In this context, we present relations between CMB observables that can be directly tested against observational data. In particular, we show that the presence of a thermal bath warmer than the Hubble scale during inflation decreases the tensor-to-scalar ratio with respect to the conventional prediction in supercooled inflation, yielding r<8ntr< 8|n_t|, where ntn_t is the tensor spectral index. Focusing on supersymmetric models at low temperatures, we determine consistency relations between the observables characterizing the spectrum of adiabatic scalar and tensor modes, both for generic potentials and particular canonical examples, and which we compare with the WMAP and Planck results. Finally, we include the possibility of producing the observed baryon asymmetry during inflation through dissipative effects, thereby generating baryon isocurvature modes that can be easily accommodated by the Planck data.Comment: 14 pages, 10 figures. Published in JCA

    Bioaccessibility of antioxidants and fatty acids from Fucus spiralis

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    Fucus spiralis is an edible brown seaweed (SW) found in the Portuguese Coast. It has been reported to have high antioxidant activity, which may elicit a potential use for the food industry. However, little information is available on how the SW behaves during the digestive process and how the freeze-drying process might affect the bioaccessibility of the di erent compounds. Therefore, antioxidant activity, total polyphenols, lipid, and fatty acid contents were measured before and after in vitro simulation of the human digestive process, both in fresh and freeze-dry SW. F. spiralis had a lipid content of 3.49 +- 0.3% of dry weight (DW), which is a usual amount described for this SW genus. The total lipid bioaccessibility was 12.1 +- 0.1%. The major omega-3 fatty acid detected was eicosapentaenoic acid, 7.5 +- 0.1%, with a bioaccessibility percentage of 13.0 +- 1.0%. Four different methods—total phenolic content (TPC), ferric reducing antioxidant power (FRAP), oxygen radical absorbance capacity (ORAC), and 1,1-diphenyl-2-picryl-hydrazyl (DPPH)—were used to assess the antioxidant activity of F. spiralis. The bioaccessibility of the antioxidants studied, ranged between 42.7% and 59.5%, except the bioaccessibility of polyphenols in freeze-dried SW (23.0% +- 1.0%), suggesting that the freeze-drying process reduces the bioaccessibility of these compounds.info:eu-repo/semantics/publishedVersio

    A framework for cooperative engineering

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    This paper discusses a framework for Cooperative Engineering (CE) and itsprototype implementation. Cooperative Engineering concerns the application ofConcurrent Engineering techniques to the design and development of products and oftheir manufacturing systems by a network of companies coming together exclusively forthat purpose. CE is a common practice in many industries such as automotive, aerospace,shipbuilding, defence, and pharmaceutical. This framework provides a formal model forCE. This is done in the context of distributed hybrid systems (DHS), a modelling andcontrol framework for networked systems introduced recently by the control andcomputer science communities

    Biomedical applications of human cathelicidin

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    [Excerpt] Antimicrobial peptides (AMPs) are good candidates to treat burn wounds, a major cause of morbidity, impaired life quality and resources consumption in developed countries. Tuberculosis (TB), a disease caused by the human pathogen Mycobacterium tuberculosis, represents the second world’s deadliest infectious disease, affecting around 9 million people worldwide in 2013. Of those, about 1.1 million died from the disease. The potential of cathelicin, a human AMP, in the treatment of mycobacteriosis and wound regeneration was assessed in pre-clinical trials. (...

    Fish communities in the lower Tagus inland wetlands: from anthropogenic pressures to conservation management

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    Inland wetlands are important biodiversity hotspots and amongst the most impacted ecosystems worldwide. Conservation management and restauration actions in wetlands are thus urgently needed to reverse trends in species loss and habitat degradation, particularly in regions harbouring already endangered endemic species. Inland wetlands may play an important role in supporting endemic endangered fishes in the Lower Tagus basin, where anthropogenic pressures have been increasing, but there is a lack of studies on fish communities, and few areas are identified as inland wetlands. Here, we aim to identify small inland wetlands in the Lower Tagus River and their potential role in supporting fish species, constituting the first study to identify and evaluate the most important fish communities. Inland wetlands were identified through the usage of remote sensing techniques and the calculation of a Normalized Difference Water Index (NDWI) with Sentinel-2 imagery for the Lower Tagus region. From a total of 486 locations identified, 31 were recognized as wetlands as having potential to host fish communities, with 11 being selected for sampling after in loco assessment. Fish sampling was conducted between 6 May and 11 June 2021. Furthermore, for each wetland, we evaluated anthropogenic stressors and land use changes between 2007 and 2018, using national land use data (i.e., Carta de Uso e Ocupação do Solo). A total of 7727 fishes from eight non-native and five native species were captured. Overall, fish communities were dominated by non-native species (97% catches), but both European eel (Anguilla anguilla) and Lisbon arched-mouth nase (Iberochondrostoma olisiponense), which are globally classified as critically endangered (CR), were found in at least two wetlands. Our results suggest that, over the last 10 years, intensive agriculture decreased (on average ≈ 3%) in the areas surrounding these wetlands, being replaced by extensive agriculture or natural uses. Despite non-native fish prevalence, some wetlands may act as refuge habitats for CR fish species. These results are important for guiding the restoration of inland wetlands and promoting conservation management actions to help reverse fish diversity loss.info:eu-repo/semantics/publishedVersio
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