Resultados da pesquisa

Catálogo de Publicações - Todos

Filtros
  1. 1

    The genetic architecture of social and asocial learning in Drosophila melanogaster

    Publicação
    por Simões-Henriques, Carla
    "In an ever-changing environment, asocial and social information coexist, and animals need learning abilities to take advantage of both types of information and make informed decisions that increase their Darwinian fitness. Social information is less costly in most functional domains, updates faster, and is more prone to yield more adaptive outcomes in unexperienced animals. Asocial learning, on the other hand, informs the individual about its own preferences, limitations and adaptations, more prone to yield adaptive outcomes in experienced animals. So, asocial and social learning are different at the behavioural ecology level. But whether they rely on a shared domain-general genetic modules or on independent domain-specific genetic modules remains elusive(...)"
    2024 tese de doutoramento Portugal acesso embargado
  2. 2

    Enhancing Lexicographic Work with Terminological Method

    Publicação
    por Salgado, Ana Castro
    Outros Autores: Costa, Rute
    This paper explores the potential impact of terminology science on lexicographers’ daily activities and, consequently, on the quality of dictionaries. With a focus on lexicographic purposes, we aim to demonstrate how terminological methods can enhance the organization, structure, and description of terms in general language dictionaries. Specifically, we differentiate between lexical units and terms, employing a terminology-based methodology to represent and organize knowledge and describe terms in both conceptual and linguistic dimensions. By incorporating these methods, lexicographers can improve the accuracy and clarity of dictionary definitions and explanations. Our study uses examples from the field of Geology, including various related concepts such as <ChronostratigraphicUnit> and <GeochronologicUnit>, sourced from the Dicionário da Língua Portuguesa Contemporânea (DLPC), and updated in the Dicionário da Língua Portuguesa (DLP). Through the application of terminological methods to these concepts, we illustrate their impact on refining lexicographic content. This research contributes to the ongoing discourse on enhancing the scientificity and uniformity of specialized lexicographic content within general language dictionaries, providing insights that can inform future lexicographic practices.
    2024 documento de conferência Portugal acesso aberto
  3. 3

    Next-Generation Solar-Powering

    Publicação
    por Santos, Ivan M.
    Outros Autores: Alexandre, Miguel; Vicente, António T.; Teixeira, Cristina; Almeida, Eva; Fortunato, Elvira et al.
    Escalating environmental and energy supply concerns, coupled with an increasing interest in space exploration, are driving the development of advanced energy harvesting systems and the adoption of cutting-edge photovoltaic (PV) technologies. Photonics allows precise light manipulation in a multitude of ways, empowering PV with the means to tackle the multifaceted challenges inherent to the harsh space environment, with great potential to concomitantly spin off to on-Earth systems, prioritizing efficiency and reliability. This review thus synthesizes the key insights from the latest experimental and simulation R&D outcomes to inform the design and implementation of advanced photonic strategies for various PV applications. The state-of-the-art performance and foreground of photonic-managed thick- (single-junction crystalline silicon, c-Si, and perovskite-on-silicon tandem) and thin-film (hydrogenated amorphous silicon, a-Si:H, and perovskite) PV devices are assessed by comparison with theoretical ideal light-trapping scenarios (single-, double-pass, and Lambertian absorption models), looking also at the potential of photonic coolers as an emergent platform for effective thermal management. Finally, this work examines novel photonic approaches for spectrum modification, emphasizing the relevance of illumination-tailoring for outer space systems.
    2025 recensão Portugal acesso aberto
  4. 4

    Shallow water fish display low phenotypic plasticity to ocean warming and extreme weather events regardless of previous thermal history

    Publicação
    por Missionário, Madalena
    Outros Autores: Almeida, Célia; Fernandes, Joana Filipa; Vinagre, Catarina; Madeira, Carolina; Madeira, Diana
    Shallow water environments have long been recognized by scientists as sentinels for climate change. By analysing the impacts of ocean warming and marine heatwaves (MHW) in species from these areas, we can estimate their plasticity and hence vulnerability to thermal challenges. Pomatoschistus microps is a benthic intertidal fish species inhabiting coastal lagoons where temperature fluctuations are common. Here, we tested the effects of “Present” and “Future summer” scenarios (22 °C and 25 °C) and their respective heatwaves (27 °C and 30 °C) versus a “Control” scenario of 19 °C on warm (summer)- and cold (winter)- acclimatized fish. Then, we estimated phenotypic plasticity of critical thermal maximum (CTmax), oxygen consumption and cellular stress responses (CSR). Temperature seasonal variation and body weight (as proxy for body size) effects on fish thermal tolerance were also determined. Fish exposed to higher temperature treatments exhibited higher thermal tolerance, with this pattern being consistent for both warm- and cold-acclimatized fish. However, this difference was subtle (<4.6 %), suggesting a low capacity for acclimation. Nonetheless, warm-acclimatized fish (collected in summer) displayed significantly higher CTmax than cold-acclimatized fish (collected in winter), indicating that CTmax is influenced by seasonal thermal variation. Weight also represents a constraint factor for P. microps thermal tolerance, as heavier animals displayed lower CTmax. No alterations in O2 consumption, neither in CSR biomarkers were detected across temperature treatments, suggesting that fish were otherwise relatively insensitive to thermal fluctuations, independently of thermal history, within the thermal scenarios tested. Overall, the studied population of P. microps seems well adapted to temperature variations in their natural environment, exhibiting a large thermal safety margin (average of 11.02 °C).
    2024 artigo Portugal acesso aberto
  5. 5

    Widespread extracellular electron transfer pathways for charging microbial cytochrome OmcS nanowires via periplasmic cytochromes PpcABCDE

    Publicação
    por Portela, Pilar C.
    Outros Autores: Shipps, Catharine C.; Shen, Cong; Srikanth, Vishok; Salgueiro, Carlos A.; Malvankar, Nikhil S.
    Extracellular electron transfer (EET) via microbial nanowires drives globally-important environmental processes and biotechnological applications for bioenergy, bioremediation, and bioelectronics. Due to highly-redundant and complex EET pathways, it is unclear how microbes wire electrons rapidly (>106s−1) from the inner-membrane through outer-surface nanowires directly to an external environment despite a crowded periplasm and slow (<105s−1) electron diffusion among periplasmic cytochromes. Here, we show that Geobacter sulfurreducens periplasmic cytochromes PpcABCDE inject electrons directly into OmcS nanowires by binding transiently with differing efficiencies, with the least-abundant cytochrome (PpcC) showing the highest efficiency. Remarkably, this defined nanowire-charging pathway is evolutionarily conserved in phylogenetically-diverse bacteria capable of EET. OmcS heme reduction potentials are within 200 mV of each other, with a midpoint 82 mV-higher than reported previously. This could explain efficient EET over micrometres at ultrafast (<200 fs) rates with negligible energy loss. Engineering this minimal nanowire-charging pathway may yield microbial chassis with improved performance.
    2024 artigo Portugal acesso aberto
  6. 6

    Understanding the Potential of Light Absorption in Dots-in-Host Semiconductors

    Publicação
    por Alexandre, Miguel
    Outros Autores: Águas, Hugo; Fortunato, Elvira; Martins, Rodrigo; Mendes, Manuel J.
    The outstanding physical properties of dots-in-host (QD@Host) hetero semiconductors demand detailed methods to fundamentally understand the best routes to optimize their potentialities for different applications. In this work, a 4-band k.p-based method was developed for rock-salt quantum dots (QDs) that describes the complete optical properties of arbitrary QD@Host systems, trailblazing the way for the full optoelectronic analysis of quantum-structured solar cells. Starting with the determination of the QD bandgap and validation against well-established literature results, the electron transition rate is then computed and analyzed against the main system parameters. This is followed by a multiparameter optimization, considering intermediate band solar cells as a promising application, where the best QD configuration was determined, together with the corresponding QD@Host absorption spectrum, in view of attaining the theoretical maximum efficiency (∼50%) of this photovoltaic technology. The results show the creation of pronounced sub-bandgap absorption due to the electronic transitions from/to the quantum-confined states, which enables a much broader exploitation of the sunlight spectrum.
    2024 artigo Portugal acesso aberto
  7. 7

    Transparent nature-based luminescent solar concentrator with NIR emission and integrated thermal sensing

    Publicação
    por Correia, Sandra F. H.
    Outros Autores: P. Falcão, Bruno; Figueiredo, Gonçalo; Vaz, Bárbara M. C.; Contieri, Letícia S.; Mesquita, Leonardo M. de Souza et al.
    The engineering of luminescent solar concentrators (LSCs) offers a way to turn windows into energy-generating units while maintaining transparency. Through UV/blue down-shifting materials to the red/near-infrared (NIR) spectral region, the performance of building integrated photovoltaics is maximized without compromising indoor light quality. The most efficient solutions are based on quantum dots, which raise environmental concerns. To address this, natural renewable materials, like bacteriochlorophyll (BChl) from phototrophic bacteria were used to fabricate an LSC prototype dispersed in a styrene-ethylene-butylene-styrene (SEBS) matrix. The LSCs emit in the red/NIR region with an emission quantum yield of ∼7%, demonstrating external photon efficiency and electrical device efficiency values of ∼1.0% and ∼0.04%, respectively. The thermal dependence of the BChl/SEBS emission is used to set two independent thermometric parameters based on the emission and the electrical power generated by the LSC edge-mounted photovoltaic cells with relative sensitivity values up to ∼2% °C−1, which is a remarkable performance. This prototype was scaled up for an active area of 0.1 m2, representing the first large-area LSC using nature-based red/NIR emission centers.
    2025 artigo Portugal acesso aberto
  8. 8

    A Biochemical Deconstruction-Based Strategy to Assist the Characterization of Bacterial Electric Conductive Filaments

    Publicação
    por Silva, Marta A.
    Outros Autores: Fernandes, Ana P.; Turner, David L.; Salgueiro, Carlos A.
    Periplasmic nanowires and electric conductive filaments made of the polymeric assembly of c-type cytochromes from Geobacter sulfurreducens bacterium are crucial for electron storage and/or extracellular electron transfer. The elucidation of the redox properties of each heme is fundamental to the understanding of the electron transfer mechanisms in these systems, which first requires the specific assignment of the heme NMR signals. The high number of hemes and the molecular weight of the nanowires dramatically decrease the spectral resolution and make this assignment extremely complex or unattainable. The nanowire cytochrome GSU1996 (~42 kDa) is composed of four domains (A to D) each containing three c-type heme groups. In this work, the individual domains (A to D), bi-domains (AB, CD) and full-length nanowire were separately produced at natural abundance. Sufficient protein expression was obtained for domains C (~11 kDa/three hemes) and D (~10 kDa/three hemes), as well as for bi-domain CD (~21 kDa/six hemes). Using 2D-NMR experiments, the assignment of the heme proton NMR signals for domains C and D was obtained and then used to guide the assignment of the corresponding signals in the hexaheme bi-domain CD. This new biochemical deconstruction-based procedure, using nanowire GSU1996 as a model, establishes a new strategy to functionally characterize large multiheme cytochromes.
    2023 artigo Portugal acesso aberto
  9. 9

    The influence of flow electrode channel design on flow capacitive deionization performance

    Publicação
    por Saif, H. M.
    Outros Autores: Gebregeorgis, T. H.; Crespo, J. G.; Pawlowski, S.
    Flow capacitive deionization (FCDI) is an emerging desalination technology at which flow electrodes (shear-thinning flowable carbon slurries) are used to remove ions from saline water. The geometry of flow electrode channels, which provide the path and ensure the distribution and mixing of the flow electrodes, is one of the most important aspects to be optimized. This work presents experimental and computational fluid dynamics (CFD) modelling analysis of the influence of the geometry of flow electrode channels on FCDI performance. Flow electrode gaskets (with open, serpentine (short) horizontal and serpentine (long) vertical channels) were 3D printed using a polyethylene terephthalate glycol (PET-G) filament. The FCDI cell with a vertical serpentine flow electrode channel exhibited the poorest performance due to channel blockage by carbon particles, while the best results were achieved with a horizontal serpentine flow electrode channel. CFD simulations aided in understanding this behaviour by showing that the channel geometry strongly affects the local shear rate, and thus the local viscosity of flow electrodes. Thus, it is recommended to design channels that induce flow disturbance aiming for increasing the shear rate and hence reducing flow electrode viscosity, therefore promoting their flowability and reducing clogging chances.
    2024 artigo Portugal acesso aberto
  10. 10

    Editorial

    Publicação
    por Morais, Tânia S.
    Outros Autores: Fernandes, Alexandra R.; Baptista, Pedro V.; Gambino, Dinorah
    2022 editorial Portugal acesso aberto