74 research outputs found

    Carbon Capture and Storage

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    Climate change is one of the main threats to modern society. This phenomenon is associated with an increase in greenhouse gas (GHGs, mainly carbon dioxide—CO2) emissions due to anthropogenic activities. The main causes are the burning of fossil fuels and land use change (deforestation). Climate change impacts are associated with risks to basic needs (health, food security, and clean water), as well as risks to development (jobs, economic growth, and the cost of living). The processes involving CO2 capture and storage are gaining attention in the scientific community as an alternative for decreasing CO2 emissions, reducing its concentration in ambient air. The carbon capture and storage (CCS) methodologies comprise three steps: CO2 capture, CO2 transportation, and CO2 storage. Despite the high research activity within this topic, several technological, economic, and environmental issues as well as safety problems remain to be solved, such as the following needs: increase of CO2 capture efficiency, reduction of process costs, and verification of the environmental sustainability of CO2 storage

    Development and application of statistical methods to support air quality policy decisions

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    Tese de doutoramento. Ciências de Engenharia. Faculdade de Engenharia. Universidade do Porto. 200

    La percepción de camioneros sobre el uso de sustancias psicoactivas en el trabajo: un estudio etnog

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    Objectivos: comprender la experiencia subjetiva de camioneros con respecto al uso de sustancias psicoactivas. Método: se utilizó el método cualitativo de carácter etnográfico. Resultados: los elementos encontrados, como el alto índice de uso de sustancias, corroboran los estudios epidemiológicos sobre el tema, agregando, sin embargo, sentimientos subjetivos y testimonios. Conclusiones: existe una divergencia de opiniones que debilita la categoría en relación con la negociación para mejorar las condiciones de trabajo, mientras que el uso de sustancias ilícitas se considera normal y no se cuestiona por los sujetos.Objective: to understand the subjective experience of truck drivers regarding the use of psychoactive  substances. Method: an ethnographic approach to qualitative research was employed. Results: the discovered elements, such as high levels of substance abuse, corroborate epidemiological research about the theme including, however, subjective feelings and testimonials. Conclusions: there is a divergence of opinions that weakens the category regarding negotiation for better working conditions, while the use of illicit substances is considered normal and is unquestioned by the subjects.Objetivo: compreender a experiência subjetiva de caminhoneiros em relação ao uso de substâncias psicoativas. Método: utilizou-se método qualitativo de caráter etnográfico. Resultados: os elementos encontrados, tais como elevado índice de consumo de substâncias, corroboram estudos epidemiológicos acerca da temática, acrescentando, todavia, sentidos subjetivos e depoimentos. Conclusão: há uma divergência de opiniões que enfraquece a categoria em relação à negociação por melhores condições de trabalho, ao mesmo tempo que o uso de substâncias ilícitas é considerado normal e não é questionado por parte dos participantes

    COMPORTAMENTO DO FOGO EM DIFERENTES PERÍODOS E CONFIGURAÇÕES DE UMA PAISAGEM NO NORDESTE DE PORTUGAL

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    In this study, we discuss the importance of land use, land cover planning and forest stand management in fire hazard reduction, through the analysis of fire behavior in relation to landscape changes in Deilão, northeastern Portugal. Markov chains and cellular automata model were used to project future landscapes whose structures were quantified by landscape metrics. FlamMap model was used to simulate fire behavior. According to landscape metrics from Fragstats, we observe that scenarios and projections in Deilão have a trend towards landscape simplification, which may facilitate the occurrence of larger, more severe fires. The analyses indicate an increased fire hazard trend in the region, largely caused by the continuity of forest cover. To avoid such impacts, forest management and landscape development should be modified in order to reduce the accumulation of combustible materials.Neste trabalho aborda-se a importância do planejamento do uso e ocupação do solo, e do manejo dos sistemas florestais na redução do perigo de incêndio, analisando-se o comportamento do fogo em relação às alterações na paisagem da Deilão, nordeste de Portugal. Foram utilizadas cadeias de Markov e modelos de autômatos celulares como metodologia para projetar a paisagem no futuro. FlamMap foi utilizado para simular o comportamento do fogo. De acordo com as métricas da paisagem obtidas no Fragstats, observou-se que os cenários e projeções em Deilão têm uma tendência à simplificação da paisagem, o que pode facilitar a ocorrência de incêndios maiores e mais graves. A análise dos resultados indicou uma tendência ao aumento do perigo de incêndios na região, em grande parte, ocasionado pela expansão de plantações contínuas de florestas. Para evitar tais impactos, o manejo florestal e ordenamento da paisagem devem ser modificados a fim de se reduzir o acúmulo de materiais combustíveis

    MAMMALS IN PORTUGAL : A data set of terrestrial, volant, and marine mammal occurrences in P ortugal

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    Mammals are threatened worldwide, with 26% of all species being includedin the IUCN threatened categories. This overall pattern is primarily associatedwith habitat loss or degradation, and human persecution for terrestrial mam-mals, and pollution, open net fishing, climate change, and prey depletion formarine mammals. Mammals play a key role in maintaining ecosystems func-tionality and resilience, and therefore information on their distribution is cru-cial to delineate and support conservation actions. MAMMALS INPORTUGAL is a publicly available data set compiling unpublishedgeoreferenced occurrence records of 92 terrestrial, volant, and marine mam-mals in mainland Portugal and archipelagos of the Azores and Madeira thatincludes 105,026 data entries between 1873 and 2021 (72% of the data occur-ring in 2000 and 2021). The methods used to collect the data were: live obser-vations/captures (43%), sign surveys (35%), camera trapping (16%),bioacoustics surveys (4%) and radiotracking, and inquiries that represent lessthan 1% of the records. The data set includes 13 types of records: (1) burrowsjsoil moundsjtunnel, (2) capture, (3) colony, (4) dead animaljhairjskullsjjaws, (5) genetic confirmation, (6) inquiries, (7) observation of live animal (8),observation in shelters, (9) photo trappingjvideo, (10) predators dietjpelletsjpine cones/nuts, (11) scatjtrackjditch, (12) telemetry and (13) vocalizationjecholocation. The spatial uncertainty of most records ranges between 0 and100 m (76%). Rodentia (n=31,573) has the highest number of records followedby Chiroptera (n=18,857), Carnivora (n=18,594), Lagomorpha (n=17,496),Cetartiodactyla (n=11,568) and Eulipotyphla (n=7008). The data setincludes records of species classified by the IUCN as threatened(e.g.,Oryctolagus cuniculus[n=12,159],Monachus monachus[n=1,512],andLynx pardinus[n=197]). We believe that this data set may stimulate thepublication of other European countries data sets that would certainly contrib-ute to ecology and conservation-related research, and therefore assisting onthe development of more accurate and tailored conservation managementstrategies for each species. There are no copyright restrictions; please cite thisdata paper when the data are used in publications.info:eu-repo/semantics/publishedVersio

    Geographic patterns of tree dispersal modes in Amazonia and their ecological correlates

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    Aim: To investigate the geographic patterns and ecological correlates in the geographic distribution of the most common tree dispersal modes in Amazonia (endozoochory, synzoochory, anemochory and hydrochory). We examined if the proportional abundance of these dispersal modes could be explained by the availability of dispersal agents (disperser-availability hypothesis) and/or the availability of resources for constructing zoochorous fruits (resource-availability hypothesis). Time period: Tree-inventory plots established between 1934 and 2019. Major taxa studied: Trees with a diameter at breast height (DBH) ≥ 9.55 cm. Location: Amazonia, here defined as the lowland rain forests of the Amazon River basin and the Guiana Shield. Methods: We assigned dispersal modes to a total of 5433 species and morphospecies within 1877 tree-inventory plots across terra-firme, seasonally flooded, and permanently flooded forests. We investigated geographic patterns in the proportional abundance of dispersal modes. We performed an abundance-weighted mean pairwise distance (MPD) test and fit generalized linear models (GLMs) to explain the geographic distribution of dispersal modes. Results: Anemochory was significantly, positively associated with mean annual wind speed, and hydrochory was significantly higher in flooded forests. Dispersal modes did not consistently show significant associations with the availability of resources for constructing zoochorous fruits. A lower dissimilarity in dispersal modes, resulting from a higher dominance of endozoochory, occurred in terra-firme forests (excluding podzols) compared to flooded forests. Main conclusions: The disperser-availability hypothesis was well supported for abiotic dispersal modes (anemochory and hydrochory). The availability of resources for constructing zoochorous fruits seems an unlikely explanation for the distribution of dispersal modes in Amazonia. The association between frugivores and the proportional abundance of zoochory requires further research, as tree recruitment not only depends on dispersal vectors but also on conditions that favour or limit seedling recruitment across forest types

    Mapping density, diversity and species-richness of the Amazon tree flora

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    Using 2.046 botanically-inventoried tree plots across the largest tropical forest on Earth, we mapped tree species-diversity and tree species-richness at 0.1-degree resolution, and investigated drivers for diversity and richness. Using only location, stratified by forest type, as predictor, our spatial model, to the best of our knowledge, provides the most accurate map of tree diversity in Amazonia to date, explaining approximately 70% of the tree diversity and species-richness. Large soil-forest combinations determine a significant percentage of the variation in tree species-richness and tree alpha-diversity in Amazonian forest-plots. We suggest that the size and fragmentation of these systems drive their large-scale diversity patterns and hence local diversity. A model not using location but cumulative water deficit, tree density, and temperature seasonality explains 47% of the tree species-richness in the terra-firme forest in Amazonia. Over large areas across Amazonia, residuals of this relationship are small and poorly spatially structured, suggesting that much of the residual variation may be local. The Guyana Shield area has consistently negative residuals, showing that this area has lower tree species-richness than expected by our models. We provide extensive plot meta-data, including tree density, tree alpha-diversity and tree species-richness results and gridded maps at 0.1-degree resolution

    Pervasive gaps in Amazonian ecological research

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    Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear un derstanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5–7 vast areas of the tropics remain understudied.8–11 In the American tropics, Amazonia stands out as the world’s most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepre sented in biodiversity databases.13–15 To worsen this situation, human-induced modifications16,17 may elim inate pieces of the Amazon’s biodiversity puzzle before we can use them to understand how ecological com munities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple or ganism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region’s vulnerability to environmental change. 15%–18% of the most ne glected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lostinfo:eu-repo/semantics/publishedVersio
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