Browsing by Issue Date, starting with "2023"
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- Carbon density in boreal forests responds non-linearly to temperature: an example from the Greater Khingan Mountains, northeast ChinaPublication . Liu, Yang; Trancoso, Ralph; Ma, Qin; Ciais, Philippe; Gouvêa, Lidiane; Yue, Chaofang; Assis, Jorge; Blanco, Juan A.Boreal forests play a crucial role in the global carbon (C) cycle and in climate stabilization. To better predict global C budgets, it is important to accurately estimate the size of forest C pools, and to identify the factors affecting them. We used national forest inventory data for the Greater Khingan Mountains, northeast China from 1999 to 2018 and 149 additional field plots to estimate C storage and its changes in forest vegetation, excluding C stored in soils, and to calculate the total C density in forest ecosystems. From 1999 to 2018, the vegetation C storage and density increased by 92.22 Tg and 4.30 Mg C ha-1, respectively, while the mean C sink was 4.61 Tg C yr-1. Carbon storage and density showed the same pattern, with the largest stocks in trees, followed by herbs, shrubs, and then litter. Mean C density was higher in mature forests than in young forests. The maximum C density was recorded in Populus davidiana forests, and was 2.2-times larger than in Betula davurica forests (the minimum). The mean (& PLUSMN; standard error) total C density of forest ecosystems was 111.3 & PLUSMN; 2.9 Mg C ha-1, including C stored in soils. Mean annual temperature (MAT) controlled total C density, as MAT had positive effects when it was lower than the temperature of the inflection point (-2.1 to -4.6 degrees C) and negative effects when it was above the inflection point. The rate of change in the total C density depended on the quantile points of the conditional distribution of total C density. Natural and anthropogenic disturbances had weaker effects on C density than temperature and precipitation. In conclusion, our results indicate that there might be a temperatureinduced pervasive decrease in C storage and an increase in tree mortality across Eastern Asian boreal forests with future climate warming.
- Antimicrobial activity of different nanocellulose films embedded with thyme, cinnamon, and oregano essential oils for active packaging application on raspberriesPublication . Casalini, Sara; Baschetti, Marco G.; Cappelletti, Martina; Guerreiro, Adriana; Gago, Custódia; Nici, Silvia; Antunes, Maria DulceThe study focuses on the antimicrobial activity of nanocellulose films (NFC) embedded with thyme, cinnamon, and oregano essential oils for active packaging application. The activity against model pathogenic bacteria was first tested to obtain each oil's minimum inhibitory concentration (MIC). The tests showed that the surface area of the films and the quantity of essential oil strongly influenced the antimicrobial effect. Then, the different active packaging systems were tested directly on packed raspberries to study their actual commercial packaging conditions. Through 12 days of storage at 1 & DEG;C, it was observed that thyme and oregano essential oils were more effective in maintaining the firmness and reducing the weight loss of the fruits compared to cinnamon essential oil or the control; no significant effect was observed on the other quality parameters that were considered. The essential oils independently proved effective in preventing fungal growth. However, the combined impact of thyme+oregano (NAP_TO) demonstrated the best performance.
- Enhancing anthocyanin extraction from wine lees: a comprehensive ultrasound-assisted optimization studyPublication . Umsza-Guez, Marcelo A.; Vázquez-Espinosa, Mercedes; Chinchilla, Nuria; Aliaño-González, M. J.; Oliveira de Souza, Carolina; Ayena, Kodjovi; Fernández Barbero, Gerardo; Palma, Miguel; Carrera, CeferinoWine lees, an important by-product of the wine industry, pose a major environmental problem due to the enormous quantities of solid-liquid waste that are discarded annually without defined applications. In this study, the optimization of a method based on a Box-Behnken design with surface response has been carried out to obtain extracts with high anthocyanin content and potent antioxidant activity. Six variables have been considered: %EtOH, temperature, amplitude, cycle, pH, and ratio. The developed method exhibited important repeatability properties and intermediate precision, with less than 5% CV being achieved. Furthermore, these novel methods were successfully applied to diverse wine lees samples sourced from Cabernet Sauvignon and Syrah varieties (Vitis vinifera), resulting in extracts enriched with significant anthocyanin content and noteworthy antioxidant activity. Additionally, this study evaluated the influence of grape variety, fermentation type (alcoholic or malolactic), and sample treatment on anthocyanin content and antioxidant activity, providing valuable insights for further research and application in various sectors. The potential applications of these high-quality extracts extend beyond the winemaking industry, holding promise for fields like medicine, pharmaceuticals, and nutraceuticals, thus promoting a circular economy and mitigating environmental contamination.
- The boltzmann equation and equilibrium thermodynamics in Lorentz-violating theoriesPublication . Potting, RobertusIn this work, we adapt the foundations of relativistic kinetic theory and the Boltzmann equation to particles with Lorentz-violating dispersion relations. The latter are taken to be those associated to two commonly considered sets of coefficients in the minimal Standard-Model Extension. We treat both the cases of classical (Maxwell-Boltzmann) and quantum (Fermi-Dirac and Bose-Einstein) statistics. It is shown that with the appropriate definition of the entropy current, Boltzmann's H-theorem continues to hold. We derive the equilibrium solutions and then identify the Lorentz-violating effects for various thermodynamic variables, as well as for Bose-Einstein condensation. Finally, a scenario with nonelastic collisions between multiple species of particles corresponding to chemical or nuclear reactions is considered.
- Two-stage lipid induction in the microalga tetraselmis striata CTP4 upon exposure to different abiotic stressesPublication . Monteiro, Ivo; Schüler, Lisa M.; Santos, Eunice; Pereira, Hugo; Schulze, Peter S.C.; Florindo, Claudia; Varela, João; Barreira, LuísaTetraselmis striata CTP4 is a euryhaline, robust, fast-growing microalga suitable for wastewater treatment and industrial production. Lipid production was induced through a two-stage cultivation strategy: a 1st stage under standard growth-promoting conditions (100 mu mol photons m- 2 s- 1, salinity 36 ppt and 20 degrees C) to achieve high biomass concentration and a 2nd stage of 6 days for lipid induction by the application of abiotic stresses such as nutrient depletion, high light intensity (200 and 400 mu mol photons m- 2 s- 1), high salinity (75 and 100 ppt), and extreme temperatures (5 and 35 degrees C). Although nutrient depletion always resulted in a decrease in biomass productivity, it had also the highest impact on lipid induction. The highest lipid content (43.2%) and lipid productivity (29.2 mg L-1 d-1) were obtained using a combination of nutrient depletion and high light intensity (400 mu mol m- 2 s- 1). The fatty acid profile was mainly composed of C16:0 (palmitic), C18:1 (oleic) and C18:2 (linoleic) acids. The low content of unsaturated fatty acids and absence of C18:3 (linolenic) acid render the oil of this microalga suitable for biodiesel production, a renewable source of energy.
- Dependence and risk management of portfolios of metals and agricultural commodity futuresPublication . Hanif, Waqas; Mensi, Walid; Vo, Xuan Vinh; BenSaïda, Ahmed; Hernandez, Jose Arreola; Kang, Sang HoonThis paper examines the dependence structure and the portfolio allocation characteristics of a main industrial portfolio metals (gold, platinum, palladium, aluminum, silver, copper, zinc, lead, and nickel), and of an agricultural commodities portfolio (wheat, corn, soybeans, coffee, sugar cane, sugar beets, cocoa, cotton, and lumber). Our methodology is based on regular vine copulas and the conditional Value-at-Risk. The motivation to investigate the dependence structure and connectedness between agricultural, and metal commodities is to identify ways in which agricultural and metal commodities can hedge each other and to explore the possibilities of parallel investments. The results indicate that the dependence dynamics of the main metals portfolio are characterized by symmetric features. However, the dependence dynamics of the agricultural commodities portfolio are characterized by symmetric and asymmetric features; symmetric dynamics are predominant. Finally, the metal commodities portfolio is observed to be less risky for financial resource allocation during the global financial crisis.
- Relatório Científico I: Avaliação dos ecossistemas de carbono azul em Portugal continental.Publication . Santos, Rui; Ito, Paula; de los Santos, Carmen B.Por ocasião da Conferência do Oceano das Nações Unidas, que decorreu em Lisboa em junho de 2022, a Fundação Calouste Gulbenkian lançou o projeto Gulbenkian Carbono Azul, em parceria com o Centro de Ciências do Mar (CCMAR) da Universidade do Algarve e a Associação Natureza Portugal em associação com a WWF – World Wide Fund for Nature (ANP|WWF), com o objetivo de investigar as informações disponíveis para mapear os ecossistemas marinhos e costeiros em Portugal continental que têm o potencial de sequestrar dióxido de carbono da atmosfera – os ecossistemas de carbono azul. Esta investigação científica, feita de norte a sul do país, caracteriza os ecossistemas (localização, áreas de distribuição, estado ambiental, reservas e taxas de sequestro de carbono, entre outras características) e propõe medidas adequadas de proteção e restauro.
- Retábulos no mundo português: thesaurusPublication . Lameira, Francisco; del Rio João, MartinaEste volume culmina um trabalho de muitos anos de estudo e inventariação, por parte de Francisco Lameira, em torno da noção de Retábulo, sua definição, tipologias, centros de produção, encomenda, materiais, processos técnicos, periodização e centralidade no universo artístico português, seja no continente europeu, seja nas ilhas atlânticas, no Índico e no Brasil. De todas estas questões se ocupam os autores desta obra duplamente valiosa – pela súmula que apresentam em torno do tema e, sobretudo, pelo magnífico florilégio de imagens, que o documentam visualmente.
- Universities and institutionalization of regional innovation policy in peripheral regions: insights from the smart specialization in PortugalPublication . Pinto, HugoRegional innovation policies are currently influenced by a series of territorial innovation models, with the regional innovation system (RIS) approach being one of the prominent examples. The rationale of smart specialization strategies (S3s) is deeply influenced by the RIS concept and highlights the importance of entrepreneurial discovery and shared governance by different types of actors. Among them, universities are seen as crucial for the success of S3 design and implementation. This article, mixing a policy debate perspective with analysis of recent quantitative and qualitative information about the Portuguese case, highlights relevant aspects for understanding the institutionalization of regional innovation and the role universities have in it as crucial knowledge brokers. The results have implications for regional innovation policies and in particular for the challenges that peripheral regions face.
- Multi-criteria decision process to identify groundwater potential zones using geospatial tools in the Arghandab river basin, AfghanistanPublication . Farahmand, Asadullah; Hussaini, Mohammad Salem; Jawadi, Hussain Ali; Abrunhosa, Manuel; Thomas, Brian F.This study used remote sensing (RS) and geographic information system (GIS) techniques to assess groundwater potential areas by applying two multi-criteria decision-making analyses tools in the Arghandab river basin. Twelve influencing parameters summarizing basin characteristics were gathered and generated using geospatial RS and GIS tools. The analytical hierarchy process (AHP) and analytical network process (ANP) were examined to weigh, ranking, and reclassify raster to produce groundwater potential maps. Two multi-criteria decision models were applied to compare results and suitability in the study area. The results of the AHP analysis delineate five groundwater potential zones (GWPZs) classified as very poor (29%), poor (22%), moderate (17%), high (19%), and very high (14%). On the other hand, the results of the ANP analysis classified GWPZs as very poor (25%), poor (9%), moderate (25%), high (30%), and very high (11%). To validate generated GWPZs maps, a total of 270 well locations data were utilized in the receiver operating characteristic (ROC) curve analysis. ROC model accuracy in training and validation stages is marginally higher for the ANP model (0.810 and 0.823) as compared to the AHP model (0.749 and 0.742). The groundwater potential map delineated in this study offers a preliminary assessment to scientists, public authorities, and policy makers for sustainable management of groundwater resources in the study area.